Changsha, China
Changsha, China

Central South University located in Changsha, a historic and cultural city in Hunan province, central south of the People's Republic of China. CSU was established in April 2000 on the basis of the amalgamation of the three former individual universities, namely Central South University of Mining and Technology , Hunan Medical University and Changsha Railway University . Wikipedia.

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Chen S.,Central South University | Wang G.,Central South University
Future Generation Computer Systems | Year: 2016

Mobile Social Networks (MSNs) facilitate connections between mobile devices, and are capable of providing an effective mobile computing environment for users to access, share, and distribute information. However, MSNs are virtual social spaces, the available information may not be trustworthy to all. Therefore, trust inference plays a critical role for establishing social links between mobile users. In MSNs, users' transactions will more and more be complemented with group contact. Hence, future usage patterns of mobile devices will involve more group contacts. In this paper, we describe the implicit social behavioral graph, i.e., ego-i graph which is formed by users' contacts, and present an algorithm for initiating ego-i graph. We rate these relationships to form a dynamic contact rank, which enables users to evaluate the trust values between users within the context of MSNs. We, then, calculate group-based trust values according to the level of contacts, interaction evolution, and users' attributes. Based on group-based trust, we obtain a cluster trust by the aggregation of inter group-based trust values. Due to the unique nature of MSNs, we discuss the propagation of cluster trust values for global MSNs. Finally, we evaluate the performance of our trust model through simulations, and the results demonstrate the effectiveness of group-based behavioural relationships in MSNs' information sharing system. © 2014 Elsevier B.V. All rights reserved.

Nie X.-W.,Central South University
Scripta Materialia | Year: 2011

Recently, Aufrecht et al. (Scripta Mater. 62 (2010) 227) published a paper investigating the previously proposed polytypic phase transformation C14 NbCr 2 to C15 NbCr 2. In their analysis, they considered that the phase transformation does not occur for high-purity alloys, and the conditions and small amounts of atmospheric contaminations induce the formation of an η-carbide-type phase. However, I point out here that previous experimental results do not agree well with their analysis. Aufrecht et al. also do not adequately acknowledge earlier work on this topic, and their experiments are not strict enough. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Objective To compare death rates from road traffic injuries in China in 2002-2007 when derived from police-reported data versus death registration data. Methods In China, police-recorded data are obtained from police records by means of a standardized, closed-ended data collection form; these data are published in the China statistical yearbook of communication and transportation. Official death registration data, on the other hand, are obtained from death certificates completed by physicians and are published in the China health statistics yearbook. We searched both sources for data on road traffic deaths in 2002-2007, used the χ2 test to compare the mortality rates obtained, and performed linear regression to look for statistically significant trends in road traffic mortality over the period. Findings For 2002-2007, the rate of death from road traffic injuries based on death registration data was about twice as high as the rate reported by the police. Linear regression showed a significant decrease of 27% (95% confidence interval, CI: 35-19) in the death rate over the period according to police sources but no significant change according to death registration data. Conclusion The widely-cited recent drop in road traffic mortality in China, based on police-reported data, may not reflect a genuine decrease. The quality of the data obtained from police reports, which drives decision-making by the Government of China and international organizations, needs to be investigated, monitored and improved.

Liu D.,Central South University | Cong W.L.,Kansas State University | Pei Z.J.,Kansas State University | Tang Y.,Guangdong University of Technology
International Journal of Machine Tools and Manufacture | Year: 2012

Knowing cutting force in rotary ultrasonic machining (RUM) can help optimizing input variables. RUM of brittle materials has been investigated both experimentally and theoretically. However, there are no reports on cutting force models for RUM of brittle materials. This paper presents a mechanistic model for cutting force in RUM of brittle materials. Assuming that brittle fracture is the primary mechanism of material removal in RUM of brittle materials, the cutting force model is developed step by step. On the basis of this mechanistic model, relationships between cutting force and input variables (such as spindle speed, feed rate, ultrasonic vibration amplitude, abrasive size, and abrasive concentration) are predicted. Experiments are conducted for model verification and experimental results agree well with model predictions. © 2011 Elsevier Ltd. Allrightsreserved.

Liu D.,Central South University | Tang Y.,Guangdong University of Technology | Tang Y.,Kansas State University | Cong W.L.,Kansas State University
Composite Structures | Year: 2012

Composite laminates (CFRP, GFRP, and fiber metal composite laminates) are attractive for many applications (such as aerospace and aircraft structural components) due to their superior properties. Usually, mechanical drilling operation is an important final machining process for components made of composite laminates. However, composite laminates are regarded as hard-to-machine materials, which results in low drilling efficiency and undesirable drilling-induced delamination. Therefore, it is desirable to improve the cost-effectiveness of currently-available drilling processes and to develop more advanced drilling processes for composite laminates. Such improvement and development will benefit from a comprehensive literature review on drilling of composite laminates. This review paper summarizes an up-to-date progress in mechanical drilling of composite laminates reported in the literature. It covers drilling operations (including conventional drilling, grinding drilling, vibration-assisted twist drilling, and high speed drilling), drill bit geometry and materials, drilling-induced delamination and its suppressing approaches, thrust force, and tool wear. It is intended to help readers to obtain a comprehensive view on mechanical drilling of composite laminates. © 2011 Elsevier Ltd.

Wang Y.,Central South University | Cai Z.,Central South University | Zhang Q.,University of Essex
Information Sciences | Year: 2012

Differential evolution (DE) is a class of simple yet powerful evolutionary algorithms for global numerical optimization. Binomial crossover and exponential crossover are two commonly used crossover operators in current popular DE. It is noteworthy that these two operators can only generate a vertex of a hyper-rectangle defined by the mutant and target vectors. Therefore, the search ability of DE may be limited. Orthogonal crossover (OX) operators, which are based on orthogonal design, can make a systematic and rational search in a region defined by the parent solutions. In this paper, we have suggested a framework for using an OX in DE variants and proposed OXDE, a combination of DE/rand/1/bin and OX. Extensive experiments have been carried out to study OXDE and to demonstrate that our framework can also be used for improving the performance of other DE variants. © 2011 Elsevier Inc. All rights reserved.

Selmi C.,University of California at Davis | Selmi C.,Humanitas Clinical and Research Center | Lu Q.,Central South University | Humble M.C.,National Health Research Institute
Journal of Autoimmunity | Year: 2012

The higher concordant occurrence of autoimmune diseases in monozygotic twins compared to dizygotic or sibling pairs supports the role for genetic susceptibility. For most conditions, however, concordance rates are considerably below 100% and lead to the estimate of the weight of genetics coined "heritability" In the group of autoimmune diseases heritability ranges between 0.008 and 1 with median values of approximately 0.60. A complementary term coined "environmentability" represents the environmental influence on individual phenotype, and can include dietary habits, chemicals, or hygienic conditions. Genome-wide association data in complex diseases confirmed a role for the environment in disease etiology as significantly associated polymorphisms were found only in subgroups of patients and controls. Environmental links to autoimmunity range from anecdotal associations or case series to largely investigated experimental and epidemiological studies. A bibliographic analysis reveals that the number of publications dedicated to environmental factors in autoimmunity has grown on average by 7% every year since 1997. The National Institute of Environmental Health Sciences (NIEHS) convened an expert panel workshop to review the body of literature examining the role of the environment in the development of autoimmune disease and to identify conclusions, confidences, and critical knowledge gaps in this area. The results of the workshop discussion are summarized in the articles found in this issue of the Journal of Autoimmunity. © 2012 Elsevier Ltd.

Khan Md.A.,Luzhou Medical College | Khan Md.A.,Central South University | Chen H.-C.,Central South University | Fu J.,Luzhou Medical College
Tumor Biology | Year: 2013

Twist, the basic helix-loop-helix transcription factor, is involved in the process of epithelial to mesenchymal transitions (EMTs), which play an essential role in cancer metastasis. Overexpression of Twist or its promoter methylation is a common scenario in metastatic carcinomas. Twist is activated by a variety of signal transduction pathways, including Akt, signal transducer and activator of transcription 3, mitogen-activated protein kinase, Ras, and Wnt signaling. Activated Twist upregulates N-cadherin and downregulates E-cadherin, which are the hallmarks of EMT. Moreover, Twist plays an important role in some physiological processes involved in metastasis, like angiogenesis, invadopodia, extravasation, and chromosomal instability. Twist also protects cancer cells from apoptotic cell death. In addition, Twist is responsible for the stemness of cancer cells and the generation of drug resistance. Recently, targeting Twist has gained significant interests in cancer therapeutics. The inactivation of Twist by small RNA technology or chemotherapeutic approach has been proved successful. Moreover, several inhibitors which are antagonistic to the upstream or downstream molecules of Twist signaling pathways have also been identified. Development of potential treatment strategies by targeting Twist has a great promise in cancer therapeutics. © 2013 International Society of Oncology and BioMarkers (ISOBM).

Liao J.,Central South University | Chang C.,University of California at Davis | Wu H.,Central South University | Lu Q.,Central South University
Autoimmunity Reviews | Year: 2015

Systemic lupus erythematosus (SLE) is a female predominant autoimmune disease characterized by multi-organ disorders. The pathogenesis of SLE is complex. Corticosteroids and immunosuppressive drugs are widely used to treat patients with SLE. However, these indiscriminate suppressors of the immune-mediated inflammatory aberration treat SLE at the cost of considerable adverse effects. Undoubtedly, there is a need for safer and more effective treatments for SLE. Cell-based therapies, although very much in their infancy, are of increasing interest in the treatment of SLE due to their potential for long-term suppression or a possible cure of the disease. Several immunoregulatory cell types, including regulatory T cells, mesenchymal stem cells, B-cells and natural killer cells, have recently been developed as novel products for tolerance-promoting therapies. Here, we provide a brief overview of current research of new cell-based therapeutic approaches that have undergone pre-clinical or clinical trials in the treatment of SLE. © 2014 Elsevier B.V..

Zheng Z.Q.,Central South University | Liu W.Q.,Shanghai University | Liao Z.Q.,Central South University | Ringer S.P.,University of Sydney | Sha G.,University of Sydney
Acta Materialia | Year: 2013

An Al-3.5Cu-0.4Mg alloy with 0.2 wt.% Ge added exhibited an enhanced age-hardening response as indicated by 50% reduction in peak ageing time and 25% increase in the peak hardness during ageing at 200 C. The clustering and partitioning behaviours of solutes in the alloy during ageing were investigated in detail using atom probe tomography. For the first time, two types of solute clusters, i.e. MgGe-rich clusters and Cu-rich clusters, are found to form in the alloy microalloyed with Ge, and they have different formation kinetics. In the as-quenched state, these small MgGe-rich clusters, rapidly formed in a high number density, did not produce an additional strengthening effect above the strength of an as-quenched Al-3.5Cu-0.4Mg base alloy. They assisted the subsequent formation of fine MgGe-rich needles during ageing. These fine needles serve as a major strengthening component and are responsible for an accelerated age-hardening response of the alloy. By contrast, the later formed Cu-rich clusters assisted the formation of strengthening θ′ precipitates (θ′ platelets and elongated θII′ precipitates) in the alloy. The effective stimulation of forming fine MgGe-rich needles by Ge addition makes the alloy possess a high strength after a prolonged ageing. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

He Y.,Yunnan Nationalities University | Shen R.,Central South University
Journal of the American Chemical Society | Year: 2013

In this paper we present a new paradigm for designing hydrogelators that exhibit sharp phase transitions in response to a series of disparate stimuli, including oxidation-reduction reactions (redox), guest-host interactions, and pH changes. We have serendipitously discovered that ferrocenoyl phenylalanine (Fc-F) monomers aggregate in water via a rapid self-assembly mechanism to form stable, multistimuli hydrogels. In comparison to other known mono- and multiresponsive gelators, Fc-F is unique because of its small size, economy of gel-forming components, and exceptionally simple molecular structure. Density functional theory (DFT) ab initio calculations suggest gel formation initially involves an antiparallel, noncovalent dimerization step wherein the ferrocenoyl moiety of one axe-like monomer conjoins with the phenyl group of the second monomer via a π-π stacking interaction to form brick-like dimers. This stacking creates a cavity in which the carboxylic acid groups of each monomer mutually interact via hydrogen bond formation, which affords additional stability to the dimer. On the basis of structural analysis via optical and electrical measurements and additional DFT calculations, we propose a possible stepwise hierachical assembly mechanism for fibril formation. Insights into the self-assembly pathway of Fc-F should prove useful for understanding gelation processes of more complex systems. We expect that Fc-F will serve as a helpful archetypical template for others to use when designing new, stimuli specific hydrogelation agents. © 2013 American Chemical Society.

Wen H.-L.,Central South University | Wen H.-L.,Sichuan Academy of Medical science | Liang Z.-S.,Central South University | Zhang R.,The Seventh Peoples Hospital of Chengdu | Yang K.,Central South University
Cardiovascular Diabetology | Year: 2013

Aims: Given the importance of inflammation in the onset and progression of diabetic cardiomyopathy, we investigated the potential protective effects of triptolide, an anti-inflammatory agent, in streptozotocin-induced diabetic rat model and in H9c2 rat cardiac cells exposed to high glucose. Methods and results: Diabetic rats were treated with triptolide (100, 200, or 400 μg/kg/day respectively) for 6 weeks. At the end of this study, after cardiac function measurements were performed, rats were sacrificed and their hearts were harvested for further histologic and molecular biologic analysis. Enhanced activity and expression of nuclear factor-kappaB (NF-κB) p65 in diabetic hearts were associated with increased inflammatory response, as demonstrated by increased pro-inflammatory cytokines, cell adhesion molecules and invading inflammatory cells, as well as increased fibrosis, in line with impaired left ventricular function. Triptolide attenuated these morpho-functional alterations. Furthermore, triptolide (20 ng/ml) also attenuated high glucose-induced inflammation in H9c2 rat cardiac cells. Conclusion: Our data demonstrate that anti-inflammatory effects of triptolide involving the NF-κB signaling pathway can improve left ventricular function under diabetic conditions, suggesting triptolide treatment might be beneficial in diabetic cardiomyopathy. © 2013 Wen et al.; licensee BioMed Central Ltd.

Bao J.,Central South University | Yuan C.,University of Swansea
Infinite Dimensional Analysis, Quantum Probability and Related Topics | Year: 2014

In this note, we discuss strong convergence of exponential integrator scheme based on spatial and time discretization for a class of neutral stochastic partial differential equations driven by α-stable processes. © 2014 World Scientific Publishing Company.

Wang Y.,Central South University | Cai Z.,Central South University | Zhang Q.,University of Essex
IEEE Transactions on Evolutionary Computation | Year: 2011

Trial vector generation strategies and control parameters have a significant influence on the performance of differential evolution (DE). This paper studies whether the performance of DE can be improved by combining several effective trial vector generation strategies with some suitable control parameter settings. A novel method, called composite DE (CoDE), has been proposed in this paper. This method uses three trial vector generation strategies and three control parameter settings. It randomly combines them to generate trial vectors. CoDE has been tested on all the CEC2005 contest test instances. Experimental results show that CoDE is very competitive. © 2010 IEEE.

Peng Z.,Central South University | Peng Z.,Michigan Technological University | Hwang J.-Y.,Michigan Technological University
International Materials Reviews | Year: 2015

Microwave heating has been extensively explored in various fields of materials processing. This technology exhibits unique characteristics including volumetric and selective heating, which eventually lead to many exceptional advantages over conventional processing methods including both energy and cost savings, improved product quality, faster processing and greater ecofriendliness, making microwave heating appropriate for applications in metallurgy. This paper presents a critical review on the use of microwave energy in metallurgy, with emphasis on both fundamentals of microwave heating and recent experimental efforts on extractive metallurgy via pyrometallurgical and/or hydrometallurgical routes. Applications to metallurgical processes for extraction of various metals, including heavy metals (Fe, Ni, Co, Cu, Pb and Zn), light metals (Al and Mg), rare metals (Ti, Mo, W and Re) and precious metals (Au, Ag and Pt), are reviewed and discussed. © 2015 Institute of Materials, Minerals and Mining and ASM International.

Liu F.,Central South University | Chen D.-D.,Shanghai Institute of Diabetes | Sun X.,Shanghai University | Xie H.-H.,Shanghai Institute of Diabetes | And 3 more authors.
Diabetes | Year: 2014

Impaired angiogenesis and its induced refractory wound lesions are common complications of diabetes. Hydrogen sulfide (H2S) has been reported to have proangiogenic effects. We hypothesize that H2S improves diabetic wound healing by restoring endothelial progenitor cell (EPC) function in type 2 diabetes. db/db Mice were treated with sodium hydrosulfide (NaHS), 4-hydroxythiobenzamide group (HTB), or saline for 18 days. db/+ Mice were treated with DL-propargylglycine (PAG) or saline for 18 days. Plasma H 2S levels were significantly decreased in db/db mice and restored in the NaHS and HTB mice compared with the diabetic control group. Wound-closure rates were significantly faster in the NaHS and HTB groups than in the db/db group, in which the PAG group had slower wound-closure rates. Wound skin capillary densities were enhanced in the NaHS and HTB groups. EPC functions were significantly preserved in the NaHS and HTB groups but were decreased in the PAG group. Meanwhile, EPC functions of the db/+ mice were significantly reduced after in vitro PAG treatment or cystathionine-γ-lyase (CSE) silencing; EPC functions of db/db mice were significantly improved after in vitro NaHS treatment. The expressions of Ang-1 in wound skin tissue and in EPCs were upregulated in the NaHS and HTB groups compared with db/db controls, but were downregulated by in vivo PAG and in vitro siCSE treatment compared with normal controls. Diabetic EPC tube formation capacity was significantly inhibited by Ang-1 small interfering RNA before NaHS treatment compared with db/db EPCs treated with NaHS only. Taken together, these results show that H2S improves wound healing by restoration of EPC functions and activation of Ang-1 in type 2 diabetic mice. © 2014 by the American Diabetes Association.

Xu H.-Z.,The University of Oklahoma Health Sciences Center | Xu H.-Z.,Central South University | Le Y.-Z.,The University of Oklahoma Health Sciences Center | Le Y.-Z.,Dean A Mcgee Eye Institute
Investigative Ophthalmology and Visual Science | Year: 2011

PURPOSE. The outer blood-retina barrier (BRB) separates the neural retina from the choroidal vasculature, which is responsible for approximately 80% of blood supplies in the eye. To determine the significance of outer BRB breakdown in diabetic retinopathy, the outer BRB-specific leakage of macromolecules in diabetic and ischemic rodents was investigated. METHODS. Diabetes and ischemia were induced in rodents by streptozotocin and oxygen-induced retinopathy, respectively. Diabetic and ischemic rodents were injected intravenously with fluorescein isothiocyanate (FITC)-dextran. The outer BRB-specific leakage in diabetic and ischemic rodents was visualized by fluorescent microscopy. RESULTS. A microscopic imaging assay was developed to examine outer BRB breakdown. The outer BRB-specific leakage of fluorescent macromolecules was visualized in diabetic and ischemic rodents. Substantial leakages of macromolecules through the outer BRB in diabetic and ischemic rodents were detected with this assay. The number of severe outer BRB leakage sites is inversely proportional to the size of macromolecules. Significant depletion of occludin in the RPE of ischemic and diabetic rodents was also observed. CONCLUSIONS. For the first time, a microscopic imaging assay for directly visualizing macromolecules leaked through the outer BRB in rodents was developed. Using this assay, the authors demonstrated the significance of outer BRB breakdown in diabetes and ischemia, which will have implications to the understanding, diagnosis, and treatment of diabetic macular edema and other ocular diseases with outer BRB defects. The microscopic imaging assay established in this study will likely be very useful to the development of drugs for macular edema. © 2011 The Association for Research in Vision and Ophthalmology, Inc.

Chen H.,Central South University | Chen H.,Hunan University of Humanities, Science and Technology | Zhang Z.,Central South University
BMC Medical Genomics | Year: 2013

Background: The identification of microRNA-disease associations is critical for understanding the molecular mechanisms of diseases. However, experimental determination of associations between microRNAs and diseases remains challenging. Meanwhile, target diseases need to be revealed for some new microRNAs without any known target disease association information as new microRNAs are discovered each year. Therefore, computational methods for microRNA-disease association prediction have gained a lot of research interest. Methods. Herein, based on the assumption that functionally related microRNAs tend to be associated with phenotypically similar diseases, three inference methods were presented for microRNA-disease association prediction, namely MBSI (microRNA-based similarity inference), PBSI (phenotype-based similarity inference) and NetCBI (network-consistency-based inference). Global network similarity measure was used in the three methods to predict new microRNA-disease associations. Results. We tested the three methods on 242 known microRNA-disease associations by leave-one-out cross-validation for prediction evaluation, and achieved AUC values of 74.83%, 54.02% and 80.66%, respectively. The best-performed method NetCBI was then chosen for novel microRNA-disease association prediction. Some associations strongly predicted by NetCBI were confirmed by the publicly accessible databases, which indicated the usefulness of this method. The newly predicted associations were publicly released to facilitate future studies. Moreover, NetCBI was especially applicable to predicting target diseases for microRNAs whose target association information was not available. Conclusions: The encouraging results suggest that our method NetCBI can not only provide help in identifying novel microRNA-disease associations but also guide biological experiments for scientific research. © 2013 Chen and Zhang; licensee BioMed Central Ltd.

Wua J.,Central South University | Wua J.,University of Macau | Lian Z.,Central South University
Computers and Industrial Engineering | Year: 2013

We consider an M/G/1 retrial queue with negative customers and priority under Bernoulli vacation schedule subject to the server breakdowns and repairs. Arrivals of both positive customers and negative customers are two independent Poisson processes. Positive customers receive service immediately if the server is idle upon their arrivals. Otherwise, they may either with probability p join the priority queue or with complementary probability-p enter a retrial orbit. A breakdown at the busy server is represented by the arrival of a negative customer which causes the the customer being in service to be lost. The server takes Bernoulli vacation after a service or a repair completion. It is assumed that the server has arbitrary repair time and vacation time distributions. With the help of Lyapunov functions we have obtained the necessary and sufficient condition for ergodicity of embedded Markov chain. By applying the supplementary variables method, we obtain the steady-state solutions for both queueing measures and reliability quantities. Moreover, we investigate the stochastic decomposition law. Besides, some special cases of interest are discussed. Finally, the effects of various parameters on the system performance are analyzed numerically. © 2012 Elsevier Ltd. All rights reserved.

Chen H.,Central South University | Chen H.,Hunan University of Humanities, Science and Technology | Zhang Z.,Central South University
PLoS ONE | Year: 2013

Computational prediction of interactions between drugs and their target proteins is of great importance for drug discovery and design. The difficulties of developing computational methods for the prediction of such potential interactions lie in the rarity of known drug-protein interactions and no experimentally verified negative drug-target interaction sample. Furthermore, target proteins need also to be predicted for some new drugs without any known target interaction information. In this paper, a semi-supervised learning method NetCBP is presented to address this problem by using labeled and unlabeled interaction information. Assuming coherent interactions between the drugs ranked by their relevance to a query drug, and the target proteins ranked by their relevance to the hidden target proteins of the query drug, we formulate a learning framework maximizing the rank coherence with respect to the known drug-target interactions. When applied to four classes of important drug-target interaction networks, our method improves previous methods in terms of cross-validation and some strongly predicted interactions are confirmed by the publicly accessible drug target databases, which indicates the usefulness of our method. Finally, a comprehensive prediction of drug-target interactions enables us to suggest many new potential drug-target interactions for further studies. © 2013 Chen, Zhang.

Liang Y.,Central South University | Xie P.,Zhuhai Chromap Institute of Herbal Medicine Research | Chau F.,Hong Kong Polytechnic University
Journal of Separation Science | Year: 2010

Development of chromatographic fingerprint (CF) and related chemometric methods and their applications to quality control of traditional Chinese medicines (TCMs) were discussed. CF is essentially a kind of quality control method for TCMs (or Chinese herbal medicines). Also, it is a quality-relevant-data high-throughput and integral tool to explore chemically the complexity of TCMs. With the help of chemometrics, some difficulties in evaluation and analysis of CFs, such as calculation of information content, peak alignment, pattern analysis, deconvolution of overlapping peaks, etc. could be well solved. To further explore TCMs synergic quality, intensive study of CF coupled with chemometrics will create the possibility to achieve the aim to reveal the working mechanisms of TCMs and to further control and strengthen TCMs' intrinsic quality in a comprehensive manner. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

News Article | October 23, 2015

Sheets of graphene and other materials that are virtually two-dimensional hold great promise for electronic, optical, and other high-tech applications. But the biggest limitation in unleashing this potential has been figuring out how to make these materials in the form of anything larger than tiny flakes. Now researchers at MIT and elsewhere may have found a way to do so. The group has determined a way to make large sheets of one such material, called molybdenum telluride, or MoTe . The team says their method is also likely to work for many similar 2-D materials, and could make widespread applications feasible. The findings have been published in the Journal of the American Chemical Society by a team including MIT postdoc Lin Zhou; professors Mildred Dresselhaus, Jing Kong, and Tomás Palacios; and eight others at MIT, the China University of Petroleum, Central South University in China, the National Tsing-hua University in Taiwan, and Saitama University and Tohoku University in Japan. “This material has a similar bandgap to silicon” — a characteristic needed in order to make transistors and solar cells — “and in single-layer form it has a direct bandgap,” Zhou says, which allows better light emission. “It also has strong absorption for solar radiation,” which is key to making practical solar cells, she says. Molybdenum telluride can exist in two different forms; one is metallic, meaning it conducts electricity well, and the other is a natural semiconductor, lending itself to applications in electronics. Controlling how the material is made allows the researchers to create whichever form is needed for a particular use. The new method is based on chemical vapor deposition (CVD), and makes it possible to create sheets of any thickness, and of a size limited only by the dimensions of the CVD chamber used for deposition. One challenge the team had to overcome was that the atoms of molybdenum telluride are very weakly bound to each other, so the tendency of the two precursor materials to form molybdenum telluride is low. “This makes it more challenging to make, compared to other similar materials,” Zhou says. The researchers were able to overcome this by using several stages of deposition, beginning with a layer of pure molybdenum. “This method makes it easy, because you only need to control one material,” Zhou says. This step is followed by oxidation of that layer; this material is then removed and powdered tellurium is added, vaporized in a carrier gas of hydrogen and argon, at a temperature of 700 degrees Celsius. The use of hydrogen in the process, the team found, is crucial to producing a uniform MoTe film. The material should be immediately usable to create electronic devices including field-effect transistors, which the team has already demonstrated in the lab. “Our process can grow sheets that have a very large area, are very homogeneous, and have high quality,” Zhou says. The team now aims to explore adapting this process to create large sheets of other promising thin materials: “2-D materials are a big family with different properties,” Zhou says. She and her colleagues will examine whether versions of the process can work with other compounds. Molybdenum telluride also lends itself to applications in spintronics, Zhou says, an emerging technology based on the spins of electrons rather than their charge, as in conventional electronics. Physicist Ado Jorio of the Federal University of Minas Gerais, Brazil, who was not involved in this work, says, “What is most impressive is that this group has been able to consecutively develop new formulae to produce almost any low-dimensional material they want, always scalable with the highest quality worldwide.” And Vincent Meunier, a physicist at Rensselaer Polytechnic Institute who was also not associated in this research, adds, “One of the many advantages of the proposed approach stems from its simplicity. The consequences of this development are likely to be numerous, as it provides a versatile and scalable technique to develop macroscopic amounts of atomically thin films, thereby surmounting major roadblocks faced by layered-materials based research so far.” The work was supported by the National Science Foundation, the Office of Naval Research, and the International Postdoctoral Exchange Fellowship Program.

News Article | December 12, 2016

DALLAS, Dec. 12, 2016 - UT Southwestern Medical Center researchers have found that intermittent fasting inhibits the development and progression of the most common type of childhood leukemia. This strategy was not effective, however, in another type of blood cancer that commonly strikes adults. "This study using mouse models indicates that the effects of fasting on blood cancers are type-dependent and provides a platform for identifying new targets for leukemia treatments," said Dr. Chengcheng "Alec" Zhang, Associate Professor of Physiology at UT Southwestern and senior author of the study, published online today by Nature Medicine. "We also identified a mechanism responsible for the differing response to the fasting treatment," he added. The researchers found that fasting both inhibits the initiation and reverses the progression of two subtypes of acute lymphoblastic leukemia, or ALL - B-cell ALL and T-cell ALL. The same method did not work with acute myeloid leukemia (AML), the type that is more common in adults. ALL, the most common type of leukemia found in children, can occur at any age. Current ALL treatments are effective about 90 percent of the time in children, but far less often in adults, said Dr. Zhang, who also holds the Hortense L. and Morton H. Sanger Professorship in Oncology and is a Michael L. Rosenberg Scholar in Medical Research. The two types of leukemia arise from different bone marrow-derived blood cells, he explained. ALL affects B cells and T cells, two types of the immune system's disease-fighting white blood cells. AML targets other types of white blood cells such as macrophages and granulocytes, among other cells. In both ALL and AML, the cancerous cells remain immature yet proliferate uncontrollably. Those cells fail to work well and displace healthy blood cells, leading to anemia and infection. They may also infiltrate into tissues and thus cause problems. The researchers created several mouse models of acute leukemia and tried various dietary restriction plans. They used green or yellow florescent proteins to mark the cancer cells so they could trace them and determine if their levels rose or fell in response to the fasting treatment, Dr. Zhang explained. "Strikingly, we found that in models of ALL, a regimen consisting of six cycles of one day of fasting followed by one day of feeding completely inhibited cancer development," he said. At the end of seven weeks, the fasted mice had virtually no detectible cancerous cells compared to an average of nearly 68 percent of cells found to be cancerous in the test areas of the non-fasted mice. Compared to mice that ate normally, the rodents on alternate-day fasting had dramatic reductions in the percentage of cancerous cells in the bone marrow and the spleen as well as reduced numbers of white blood cells, he said. The spleen filters blood. "In addition, following the fasting treatment, the spleens and lymph nodes in the fasted ALL model mice were similar in size to those in normal mice. Although initially cancerous, the few fluorescent cells that remained in the fasted mice after seven weeks appeared to behave like normal cells," he said. "Mice in the ALL model group that ate normally died within 59 days, while 75 percent of the fasted mice survived more than 120 days without signs of leukemia." Fasting is known to reduce the level of leptin, a cell signaling molecule created by fat tissue. In addition, previous studies have shown weakened activity by leptin receptors in human patients with ALL. For those reasons, the researchers studied both leptin levels and leptin receptors in the mouse models. They found that mice with ALL showed reduced leptin receptor activity that then increased with intermittent fasting, he said. "We found that fasting decreased the levels of leptin circulating in the bloodstream as well as decreased the leptin levels in the bone marrow. These effects became more pronounced with repeated cycles of fasting. After fasting, the rate at which the leptin levels recovered seemed to correspond to the rate at which the cancerous ALL cells were cleared from the blood," he added. Interestingly, AML was associated with higher levels of leptin receptors that were unaffected by fasting, which could help explain why the fasting treatment was ineffective against that form of leukemia. It also suggests a mechanism - the leptin receptor pathway - by which fasting exerts its effects in ALL, he said. "It will be important to determine whether ALL cells can become resistant to the effects of fasting," he said. "It also will be interesting to investigate whether we can find alternative ways that mimic fasting to block ALL development." Given that the study did not involve drug treatments, just fasting, researchers are discussing with clinicians whether the tested regimen might be able to move forward quickly to human clinical trials Current or former UT Southwestern coauthors in Physiology involved in this research include: co-lead authors Instructor Dr. Zhigang Lu and postdoctoral researcher Dr. Jingjing Xie; senior research associate Dr. Guojin Wu; research scientist Dr. Jinhui Shen, now in Biophysics; and former Instructor Dr. Xunlei Kang. Other UTSW researchers include Dr. Robert Collins, Professor of Internal Medicine; Dr. Weina Chen, Associate Professor of Pathology; Dr. Min Luo, research scientist, Harold C. Simmons Comprehensive Cancer Center; Dr. Lily Jun-Shen Huang, Associate Professor of Cell Biology; Dr. James Amatruda, Associate Professor of Pediatrics, Internal Medicine, and Molecular Biology; Dr. Tamra Slone, Assistant Professor of Pediatrics; Dr. Naomi Winick, Professor of Pediatrics; and Dr. Philipp Scherer, Professor of Internal Medicine and Cell Biology. Dr. Collins holds the Sydney and J.L. Huffines Distinguished Chair in Cancer Research in Honor of Eugene Frenkel, M.D., and the H. Lloyd and Willye V. Skaggs Professorship in Medical Research; Dr. Amatruda holds the Nearburg Family Professorship in Pediatric Oncology Research and is a Horchow Family Scholar in Pediatrics; Dr. Winick holds the Lowe Foundation Professorship in Pediatric Neuro-Oncology; and Dr. Scherer holds the Gifford O. Touchstone, Jr. and Randolph G. Touchstone Distinguished Chair in Diabetes Research. Researchers from Central South University School of Xiangya Medicine, China, also participated. The research was supported by the National Institutes of Health; the National Heart, Lung, and Blood Institute; Leukemia & Lymphoma Society awards; and the Cancer Prevention and Research Institute of Texas (CPRIT). UTSouthwestern's Harold C. Simmons Comprehensive Cancer Center is the only NCI-designated Comprehensive Cancer Center in North Texas and one of just 47 NCI-designated Comprehensive Cancer Centers in the nation. Simmons Cancer Center includes 13 major cancer care programs and its education and training programs support and develop the next generation of cancer researchers and clinicians. Simmons Cancer Center is among only 30 U.S. cancer research centers to be designated by the National Cancer Institute as a National Clinical Trials Network Lead Academic Participating Site. UT Southwestern, one of the premier academic medical centers in the nation, integrates pioneering biomedical research with exceptional clinical care and education. The institution's faculty includes many distinguished members, including six who have been awarded Nobel Prizes since 1985. The faculty of almost 2,800 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide medical care in about 80 specialties to more than 100,000 hospitalized patients and oversee approximately 2.2 million outpatient visits a year.

Chai L.,Central South University | Wang Y.,Central South University | Zhao N.,Central South University | Zhao N.,Hunan Institute of Engineering | And 2 more authors.
Water Research | Year: 2013

A novel adsorbent of sulfate-doped Fe3O4/Al2O3 nanoparticles with magnetic separability was developed for fluoride removal from drinking water. The nanosized adsorbent was characterized and its performance in fluoride removal was evaluated. Kinetic data reveal that the fluoride adsorption was rapid in the beginning followed by a slower adsorption process, nearly 90% adsorption can be achieved within 20min and only 10-15% additional removal occurred in the following 8h. The fluoride adsorption isotherm was well described by Elovich model. The calculated adsorption capacity of this nanoadsorbent for fluoride by two-site Langmuir model was 70.4mg/g at pH 7.0. Moreover, this nanoadsorbent performed well over a considerable wide pH range of 4-10, and the fluoride removal efficiencies reached up to 90% and 70% throughout the pH range of 4-10 with initial fluoride concentrations of 10mg/L and 50mg/L, respectively. The observed sulfate-fluoride displacement and decreased sulfur content on the adsorbent surface reveal that anion exchange process was an important mechanism for fluoride adsorption by the sulfate-doped Fe3O4/Al2O3 nanoparticles. Moreover, a shift of the pH of zero point charge (pHPZC) of the nanoparticles and surface analysis based on X-ray photoelectron spectroscopy (XPS) suggest the formation of inner-sphere fluoride complex at the aluminum center as another adsorption mechanism. With the exception of PO4 3-, other co-existing anions (NO3 -, Cl- and SO4 2-) did not evidently inhibit fluoride removal by the nanoparticles. Findings of this study demonstrate the potential utility of the nanoparticles as an effective adsorbent for fluoride removal from drinking water. © 2013 Elsevier Ltd.

Wang S.,Georgia Regents University | Dong Z.,Georgia Regents University | Dong Z.,Central South University
American Journal of Physiology - Renal Physiology | Year: 2013

Cilia, membraneenclosed organelles protruding from the apical side of cells, can be divided into two classes: motile and primary cilia. During the past decades, motile cilia have been intensively studied. However, it was not until the 1990s that people began to realize the importance of primary cilia as cellular-specific sensors, particularly in kidney tubular epithelial cells. Furthermore, accumulating evidence indicates that primary cilia may be involved in the regulation of cell proliferation, differentiation, apoptosis, and planar cell polarity. Many signaling pathways, such as Wnt, Notch, Hedgehog, and mammalian target of rapamycin, have been located to the primary cilia. Thus primary cilia have been regarded as a hub that integrates signals from the extracellular environment. More importantly, dysfunction of this organelle may contribute to the pathogenesis of a large spectrum of human genetic diseases, named ciliopathies. The significance of primary cilia in acquired human diseases such as hypertension and diabetes has gradually drawn attention. Interestingly, recent reports disclosed that cilia length varies during kidney injury, and shortening of cilia enhances the sensitivity of epithelial cells to injury cues. This review briefly summarizes the current status of cilia research and explores the potential mechanisms of cilia-length changes during kidney injury as well as provides some thoughts to allure more insightful ideas and promotes the further study of primary cilia in the context of kidney injury. © 2013 by the American Physiological Society.

Patil M.,Georgia Regents University | Pabla N.,Georgia Regents University | Pabla N.,St Jude Childrens Research Hospital | Dong Z.,Georgia Regents University | Dong Z.,Central South University
Cellular and Molecular Life Sciences | Year: 2013

Originally identified as a mediator of DNA damage response (DDR), checkpoint kinase 1 (Chk1) has a broader role in checkpoint activation in DDR and normal cell cycle regulation. Chk1 activation involves phosphorylation at conserved sites. However, recent work has identified a splice variant of Chk1, which may regulate Chk1 in both DDR and normal cell cycle via molecular interaction. Upon activation, Chk1 phosphorylates a variety of substrate proteins, resulting in the activation of DNA damage checkpoints, cell cycle arrest, DNA repair, and/or cell death. Chk1 and its related signaling may be an effective therapeutic target in diseases such as cancer. © 2013 Springer Basel.

Liu J.,Central South University | Tang S.,Central South University | Lu Y.,Central South University | Cai G.,Central South University | And 3 more authors.
Energy and Environmental Science | Year: 2013

We report a simple and effective carbon-free nanocoating strategy for large-scale synthesis of Mo2N nanolayer coated MoO2 hollow nanostructures. This strategy only involves commercial MoO3 powders reacted with reduced gas. The carbon-free nanocoating of Mo2N is highly effective in improving the electrochemical properties of MoO2, promising advanced batteries with high specific capacity up to 815 mA h g -1, long cycle-life (e.g., >100 cycles) and high rate capability compared with the carbon nanocoating commonly used in electrode materials. The present nitride-nanocoating strategy is facile but effective, and therefore it is very promising for large-scale industrial production. It may be extended to prepare other metal oxides with nitride coating nanolayers to enhance their performances as electrode materials. © 2013 The Royal Society of Chemistry.

Tang C.,Central South University | Dong Z.,Central South University | Dong Z.,Georgia Regents University
Kidney International | Year: 2015

Epigenetic mechanisms have been implicated in the pathogenesis of renal diseases, including acute kidney injury (AKI). Mar et al. now unravel the acetylation and methylation at histones that are associated with the transcription of key genes in AKI. Notably, histone modifications display a remarkable heterogeneity in ischemic and endotoxic AKI. Targeting epigenetic programs may offer novel strategies to protect kidneys from AKI and enhance kidney repair and recovery.

Miura H.,University of Electro - Communications | Maruoka T.,University of Electro - Communications | Yang X.,Central South University | Jonas J.J.,McGill University
Scripta Materialia | Year: 2012

A Mg-Al-Zn alloy was multi-directionally forged at room temperature to cumulative strains of ΣΔ = 2.0. The coarse initial grains were gradually subdivided into ultrafine ones by mechanical twins. A small pass strain of Δ = 0.1 was employed and generations of twins effectively suppressed the development of sharp textures, enabling severe plastic deformation at ambient temperature. Tensile testing revealed an excellent balance of mechanical properties: 480 MPa yield stress, 525 MPa ultimate tensile strength and 5% plastic strain to fracture. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Li Y.,Central South University | Li Y.,University of Illinois at Urbana - Champaign | Liao S.,Central South University | Liu G.,Central South University
International Journal of Electrical Power and Energy Systems | Year: 2015

A 100 kW regenerative Brayton heat engine driven by the hybrid of fossil fuel and solar energy was considered for optimization based on multiple criteria. A thermodynamic model of such hybrid system was developed so that the power output, thermal efficiency and dimensionless thermo-economic performance with the imperfect performance of parabolic dish solar collector, the external irreversibility of Brayton heat engine and conductive thermal bridging loss could be obtained. Evolutionary algorithm based on NSGA-II (Elitist Non-dominated Sorting Genetic Algorithm) was employed to optimize triple-objective and dual-objective functions, where the temperatures of hot reservoir, cold reservoir and working fluid, the effectiveness of hot-side heat exchanger, cold-side heat exchanger and regenerator were considered as design variables. Using decision makings, including Shannon Entropy, LINMAP and TOPSIS methods, the final optimal solutions were selected from Pareto frontier obtained by NSGA-II. The results show that there exists an appropriate working fluid temperature to cause optimal solution under each given condition. The comparisons of triple-objective and dual-objective optimization with single-objective optimization indicate that multi-objective optimization can yield the more suitable results due to the lower deviation index from the ideal solution. In the analysis of triple-objective optimization, an expected result is obtained that the optimal values of the power out, efficiency and dimensionless thermo-economic performance of solar-dish Brayton system (68.65 kW, 0.2331 and 0.3077) are 22.6%, 34.9% and 18.4% respectively less than that of convectional Brayton heat engine. Finally, a range of functional relationship between the optimized objectives in Pareto frontier is fitted to provide more detailed insight into the optimal design of solar-dish Brayton system. © 2014 Elsevier Ltd. All rights reserved.

Wang L.-P.,Central South University | Wang L.-P.,CAS Institute of Physics | Chen L.-M.,Central South University
Materials Characterization | Year: 2012

Pure monoclinic and tetragonal LaVO 4:Eu nanocrystals with various morphologies were successfully synthesized by a hydrothermal method in the presence of ethylenediaminetetraacetic acid [EDTA or H 4L, where L 4- = (CH 2COO) 2 N (CH 2) 2 N(CH 2COO) 2 4-]. It was found that tuning the pH of the growth solution was a crucial step for the synthesis of LaVO 4:Eu nanocrystals with controllable crystal structure and morphology. When the pH value was lower than 2.5, urchin-like monoclinic LaVO 4:Eu nanostructures were obtained. Increasing the pH value can induce the phase transformation from monazite to zircon type accompanied with the morphology transformation: urchin-like → bundle → nanorod/nanowire. In addition, the concentration of EDTA also played an important role in determining the aspect ratio of tetragonal LaVO 4:Eu nanorods. The possible mechanism responsible for the phase control and morphology evolution of the LaVO 4:Eu nanocrystals was discussed. Their luminescent properties were systematically studied. It demonstrated that the phase transformation from monazite to zircon type and the increase in the aspect ratio of LaVO 4:Eu nanorods resulted in a remarkable improvement of the luminescent properties. © 2012 Elsevier Inc. All rights reserved.

Yang J.,Central South University | Yan D.,CAS Changchun Institute of Applied Chemistry | Jones T.S.,University of Warwick
Chemical Reviews | Year: 2015

Molecular template growth (MTG) is a newly developed method for fabricating high-quality organic semiconductor thin films with controllable morphologies, molecular orientations, electronic structures, and interface properties to produce high-performance organic electronic and optoelectronic devices. There are several MTG methods with different molecular template materials and growth behaviors, including multiphenyl- and multithiophene-based MTG, and perylene-derivative MTG. Extensive research works have also revealed that Individualized methods for fabricating high-quality organic semiconductor thin films with controllable thin-film properties can be developed on the basis of specific understandings of the growth behaviors of organic semiconductor molecules and the desired device structures.

Wan P.,Shanghai JiaoTong University | Yu X.,Central South University | Xia Q.,Shanghai JiaoTong University
Liver Transplantation | Year: 2014

Living donor liver transplantation (LDLT) has emerged as an alternative to deceased donor liver transplantation (DDLT) because of the increasing number of patients waiting for liver transplantation (LT). However, whether it can achieve operative outcomes similar to those achieved with DDLT for adult patients remains controversial. We conducted this meta-analysis to compare the operative outcomes of LDLT and DDLT recipients. A literature search was performed to identify clinical controlled studies comparing LDLT and DDLT that were published before October 2013. Four perioperative outcomes [duration of the recipient operation (DRO), red blood cell (RBC) transfusion requirement, length of the hospital stay, and cold ischemia time (CIT)] and 5 postoperative complication outcomes (biliary complications, vascular complications, intra-abdominal bleeding, perioperative death, and retransplantation) were the main outcomes assessed. Nineteen studies with a total of 5450 patients were included in the meta-analysis. In comparison with DDLT, LDLT was associated with a significantly longer DRO and a shorter CIT. We found that biliary complications [odds ratio (OR)=3.08, 95% confidence interval (CI)=1.97-4.81, P<0.001], vascular complications (OR=2.16, 95% CI=1.32-3.54, P=0.002), and retransplantation (OR=1.76, 95% CI=1.09-2.83, P=0.02) occurred more frequently for LDLT recipients, and the subgroup analysis indicated that the biliary complication rate decreased dramatically with greater LDLT experience. No significant difference was observed in RBC transfusion requirements, the lengths of hospital stays, intra-abdominal bleeding rates, or perioperative mortality between LDLT and DDLT recipients. In conclusion, LDLT is associated with a higher rate of surgical complications after transplantation. A reduction of postoperative complication rates can be achieved as centers gain greater experience with LDLT. However, LDLT is still an excellent alternative to DDLT because it facilitates access to LT. © 2014 American Association for the Study of Liver Diseases.

Tang Y.-L.,Emory University | Xiang X.-J.,Central South University | Wang X.-Y.,Central South University | Cubells J.F.,Emory University | And 2 more authors.
Bulletin of the World Health Organization | Year: 2013

In China, alcohol consumption is increasing faster than anywhere else in the world. A steady increase in alcohol production has also been observed in the country, together with a rise in alcohol-related harm. Despite these trends, China's policies on the sale and consumption of alcoholic beverages are weak compared with those of other countries in Asia. Weakest of all are its policies on taxation, drink driving laws, alcohol sale to minors and marketing licenses. The authors of this descriptive paper draw attention to the urgent need for public health professionals and government officials in China to prioritize population surveillance, research and interventions designed to reduce alcohol use disorders. They describe China's current alcohol policies and recent trends in alcohol-related harm and highlight the need for health officials to conduct a thorough policy review from a public health perspective, using as a model the World Health Organization's global strategy to reduce the harmful use of alcohol.

Cao S.,Yancheng Institute of Technology | Jiang X.,Central South University | Chen J.,Yancheng Institute of Technology
Journal of Inorganic Biochemistry | Year: 2010

The impact of Zn2+ ion on interactions of flavonols galangin (Gal), kaempferol (Kae), quercetin (Que) and myricetin (Myr) with bovine serum albumin (BSA) in aqueous solution were studied by fluorescence quenching technique. The results exhibited that Zn2+ ion affected significantly the interactions and the effect was distinct for the flavonol bearing different number of B-ring hydroxyl. Each flavonol can quench the fluorescence of BSA, displaying a quenching extent of Myr > Que > Kae > Gal, which is in good agreement with the number variation of the B-ring hydroxyl. The presence of Zn2+ ion promoted the quenching for the flavonols, exhibiting an extent of Que > Myr > Kae > Gal. The values of Ka for Kae, Que and Myr decreased whereas KSV and kq for Gal, Kae and Que increased with the number of B-ring hydroxyl. The type of BSA fluorescence quenching for Gal, Kae and Que hardly changed but the preference of static quenching increased. The values of KSV and kq for Myr remarkably decreased and the fluorescence quenching of BSA alternatively occurred via both static and dynamic type instead of only one (static or dynamic). The results suggest the key role of the B-ring hydroxyl and the distinct effect of its number in the interactions. Each flavonol may capture the BSA-bound ZnII in the solution, forming ZnII-flavonol complex that is possibly responsible for BSA fluorescence quenching. The B-ring hydroxyl could establish hydrogen bonds with BSA in the absence of Zn2+ and act as donors for chelating in the presence of Zn2+. The formation of dinuclear ZnII-Myr complex together with the hydrogen bonds between the free B-ring hydroxyl and BSA may contribute to the exceptional behavior of Myr. © 2009 Elsevier Inc. All rights reserved.

Liu L.,Anyang University, China | Li S.,Anyang University, China | Deng D.,Anyang University, China | Xia N.,Central South University
Analyst | Year: 2012

In this paper, we report a simple, sensitive and selective colorimetric visualization of dopamine (DA) using dithiobis(succinimidylpropionate) (DSP)-modified gold nanoparticles (AuNPs) as probes and ferric ions as cross-linkers. Via the standard amine coupling reaction between the amino groups of DA and activated carboxyl groups of DSP, DA molecules can be assembled onto the surface of DSP-AuNPs. Accordingly, Fe3+ ions induce a change of DSP-AuNPs in color and UV-vis absorbance by coordinating to the catechol groups of the anchored DA. The pH dependence and mechanism of this method are discussed. A detection limit of 2 nM was obtained, which is lower than those achievable with currently used chromatographic and electrochemical techniques. The feasibility for the detection of DA in artificial cerebrospinal fluid has been demonstrated. © 2012 The Royal Society of Chemistry.

Zhan M.,Central South University | Brooks C.,Georgia Regents University | Liu F.,Central South University | Sun L.,Central South University | And 2 more authors.
Kidney International | Year: 2013

Mitochondria are a class of dynamic organelles that constantly undergo fission and fusion. Mitochondrial dynamics is governed by a complex molecular machinery and finely tuned by regulatory proteins. During cell injury or stress, the dynamics is shifted to fission, resulting in mitochondrial fragmentation, which contributes to mitochondrial damage and consequent cell injury and death. Emerging evidence has suggested a role of mitochondrial fragmentation in the pathogenesis of renal diseases including acute kidney injury and diabetic nephropathy. A better understanding of the regulation of mitochondrial dynamics and its pathogenic changes may unveil novel therapeutic strategies. © 2013 International Society of Nephrology.

Cao J.,Central South University | Cao J.,Hunan Institute of Engineering | Chen H.,Central South University
Mathematical and Computer Modelling | Year: 2012

In this paper, we study certain impulsive functional fractional differential equations with nonlinear boundary conditions. By means of monotone iterative method coupled with lower and upper solutions, some new sufficient conditions for the existence of solutions are established. © 2011.

Wu Y.-L.,Guangdong General Hospital and Guangdong Academy of Medical science | Zhou C.,Shanghai Pulmonary Hospital | Hu C.-P.,Central South University | Feng J.,Jiangsu Provincial Tumor Hospital | And 11 more authors.
The Lancet Oncology | Year: 2014

Background: Afatinib-an oral irreversible ErbB family blocker-improves progression-free survival compared with pemetrexed and cisplatin for first-line treatment of patients with EGFR mutation-positive advanced non-small-cell lung cancer (NSCLC). We compared afatinib with gemcitabine and cisplatin-a chemotherapy regimen widely used in Asia-for first-line treatment of Asian patients with EGFR mutation-positive advanced NSCLC. Methods: This open-label, randomised phase 3 trial was done at 36 centres in China, Thailand, and South Korea. After central testing for EGFR mutations, treatment-naive patients (stage IIIB or IV cancer [American Joint Committee on Cancer version 6], performance status 0-1) were randomly assigned (2:1) to receive either oral afatinib (40 mg per day) or intravenous gemcitabine 1000 mg/m2 on day 1 and day 8 plus cisplatin 75 mg/m2 on day 1 of a 3-week schedule for up to six cycles. Randomisation was done centrally with a random number-generating system and an interactive internet and voice-response system. Randomisation was stratified by EGFR mutation (Leu858Arg, exon 19 deletions, or other; block size three). Clinicians and patients were not masked to treatment assignment, but the independent central imaging review group were. Treatment continued until disease progression, intolerable toxic effects, or withdrawal of consent. The primary endpoint was progression-free survival assessed by independent central review (intention-to-treat population). This study is registered with, NCT01121393. Findings: 910 patients were screened and 364 were randomly assigned (242 to afatinib, 122 to gemcitabine and cisplatin). Median progression-free survival was significantly longer in the afatinib group (11·0 months, 95% CI 9·7-13·7) than in the gemcitabine and cisplatin group (5·6 months, 5·1-6·7; hazard ratio 0·28, 95% CI 0·20-0·39; p<0·0001). The most common treatment-related grade 3 or 4 adverse events in the afatinib group were rash or acne (35 [14·6%] of 239 patients), diarrhoea (13 [5·4%]), and stomatitis or mucositis (13 [5·4%]), compared with neutropenia (30 [26·5%] of 113 patients), vomiting (22 [19·5%]), and leucopenia (17 [15·0%]) in the gemcitabine and cisplatin group. Treatment-related serious adverse events occurred in 15 (6·3%) patients in the afatinib group and nine (8·0%) patients in the gemcitabine and cisplatin group. Interpretation: First-line afatinib significantly improves progression-free survival with a tolerable and manageable safety profile in Asian patients with EGFR mutation-positive advanced lung NSCLC. Afatinib should be considered as a first-line treatment option for this patient population. Funding: Boehringer Ingelheim. © 2014 Elsevier Ltd.

Hu Z.-Y.,CAS Shanghai Institute of Materia Medica | Yu Q.,Shanghai JiaoTong University | Pei Q.,Central South University | Guo C.,Shanghai JiaoTong University
Clinical Cancer Research | Year: 2010

Purpose: A previous meta-analysis showed that the association between the UGT1A1*28 genotype and irinotecan-induced neutropenia was influenced by irinotecan dose and that the risk of neutropenia was similar at low doses for patients with all genotypes. However, the sample sizes for the low- and high-dose groups were small. Because additional studies have now been reported, an updated and refined metaanalysis is needed. Experimental Design: Meta-analyses were done to assess the relationship between UGT1A1*28 and neutropenia. The association between UGT1A1*28 and the relative extent of glucuronidation (REG) of SN-38 was also examined. The studies included were stratified into different dose groups. Results: A total of 1,998 patients were included for the analysis of neutropenia and 581 patients were included for REG. The risk of neutropenia at low doses was significantly higher among patients with a UGT1A1*28/*28 genotype than among those carrying the UGT1A1*1 allele(s) [relative risk (RR), 2.43; 95% confidence interval, 1.34-4.39; P = 0.003]. In addition, the RR of neutropenia at low doses was comparable with that at medium doses (2.43 versus 2.00). The RR of neutropenia at high doses was significantly higher than that at low and medium doses (7.22 versus 2.04). We found the weighted mean difference of REG (UGT1A1*1/ *1 or UGT1A1*1/*28 versus UGT1A1*28/*28) increased with increasing dose of irinotecan. Conclusions: In conclusion, the UGT1A1*28/*28 genotype was associated with an increased risk of neutropenia not only at medium or high doses of irinotecan but also at low doses. The dose-dependent manner of SN-38 glucuronidation explained why the association between UGT1A1*28 and neutropenia was dose dependent. ©2010 AACR.

Wei Q.,Georgia Regents University | Dong Z.,Georgia Regents University | Dong Z.,Central South University
Kidney International | Year: 2014

Histone deacetylases (HDACs) have been implicated in the pathogenesis of kidney diseases including diabetic nephropathy (DN); however, the mechanism is poorly understood. Wang et al. unravel the changes in expression of various HDACs in DN and demonstrate that HDAC4 specifically contributes to podocyte injury in DN. HDAC4 deacetylates STAT1 to suppress autophagy, an essential cellular process for the function and viability of podocytes. The development of HDAC isoform-specific inhibitors may provide efficacious therapeutics for DN and related renal diseases.

Lu Y.,Shanghai JiaoTong University | Hu X.-B.,Central South University
Oncology Reports | Year: 2014

Complement system activation contributes to various immune and inflammatory diseases, as well as cancers. However, the role of complement activation in the proliferation of cancer cells is not clear. In the present study, we investigated the consequences of complement activation on the proliferation of breast cancer cells and its possible mechanisms. We focused our study on the potential roles of the anaphylatoxins C3a and C5a in the proliferation of human breast cancer, as two important immune mediators generated after complement activation. Our study revealed that C5a stimulation, but not C3a, enhanced the proliferation of human breast cancer cells in vitro. Moreover, the expression of response gene to complement 32 (RGC-32) was pronounced in breast cancer cells in response to C5a stimulation. Notably, blockade of the C5a receptor markedly reduced the expression of RGC-32 and the proliferation of breast cancer cells stimulated by C5a. Meanwhile, silencing of RGC-32 expression reduced the proliferation of breast cancer cells induced by C5a treatment. Further investigation revealed that Akt activation was involved in C5a-induced RGC-32 expression and breast cancer cell proliferation. In conclusion, the present study indicates that C5a may promote the proliferation of breast cancer cells through Akt1 activation of the RGC-32 gene.

Yang X.,Central South University | Miura H.,University of Electro - Communications | Sakai T.,University of Electro - Communications
Materials and Design | Year: 2013

The microstructural development in a AZ31 magnesium alloy during cold multi-directional forging followed by annealing is investigated in a wide range of cumulative strains up to 5. The kinetics of recrystallization is accelerated accompanying with increase in the Johnson-Mehl-Avrami-Kolmogorov slope from 2.6 to 4.7 as well as an appearance of a linear Johnson-Mehl-Avrami-Kolmogorov relationship. The grain size evolved after annealing decreases with repeated multi-directional forging and approaches around 1 lm in high strain. A strong initial texture is broken gradually with repeated multi-directional forging and almost disappears at severe high strain of 5. These can be because various variants of deformation twins and their intersections introduced by multi-directional forging are homogeneously developed in high density by repeated changing of the loading directions during multi-directional forging. The annealing process and the mechanisms occurring after cold multi-directional forging are discussed comparing with those after hot multi-directional forging. © 2012 Elsevier Ltd.

Lu P.-J.,Central South University | Lei M.,Beijing University of Posts and Telecommunications | Liu J.,Central South University
CrystEngComm | Year: 2014

A facile and effective method has been reported to synthesize graphene-encapsulated α-MoO3 nanoribbons by a self-assembly process between negatively charged graphene oxide and positively charged MoO3 nanoribbons. Compared to the structures of MoO3 nanobelts grown on graphene or other hybrids of MoO3 composited with carbon or non-carbon, this unique hybrid architecture of the graphene-encapsulated MoO3 nanoribbons exhibits not only a high specific capacity (up to 823 mAh g-1 after 70 cycles at 200 mA g -1), but also an excellent cycling performance (with more than 754 mAh g-1 after 200 cycles at 1000 mA g-1) as well as a greatly-enhanced high-rate capability (displaying a high discharge capacity of 710 mAh g-1 after 30 cycles at 3000 mA g-1), thus showing great potential as an anode material for lithium ion batteries. This journal is © the Partner Organisations 2014.

News Article | December 20, 2016

JUPITER, FL - Dec. 20, 2016 - Scientists from the Florida campus of The Scripps Research Institute (TSRI) have developed an efficient process to rapidly discover new "enediyne natural products" from soil microbes that could be further developed into extremely potent anticancer drugs. The study highlights microbial natural products as abundant sources of new drug leads. The researchers' discovery process involves prioritizing the microbes from the TSRI strain collection and focusing on the ones that are genetically predisposed to produce specific families of natural products. The scientists say this process saves time and resources in comparison to the traditional approaches used to identify these rare molecules. The study, led by TSRI Professor Ben Shen, was published today in the journal mBio. Shen and his colleagues uncovered a new family of enediyne natural products, called tiancimycins, (TNMs) which kill selected cancer cells more rapidly and completely in comparison to toxic molecules used in FDA-approved antibody-drug conjugates (ADCs)-- monoclonal antibodies attached to cytotoxic drugs that target only cancer cells. The scientists also discovered several new producers of C-1027, an antitumor antibiotic currently in clinical development, which can produce C-1027 at much higher levels. It has been more than a decade since Shen first reported on the C-1027 enediyne biosynthetic machinery, and he speculated then that the knowledge obtained from studying biosynthesis of C-1027, and other enediynes, could be used for the discovery of novel enediyne natural products. "The enediynes represent one of the most fascinating families of natural products for their extraordinary biological activities," Shen said. "By surveying 3,400 strains from the TSRI collection, we were able to identify 81 strains that harbor genes encoding enediynes. With what we know, we can predict novel structural insights that can be exploited to radically accelerate enediyne-based drug discovery and development." "The work described by the Shen group is an excellent example of what can be achieved by coupling state of the art genomic analyses of potential biosynthetic clusters and modern physicochemical techniques," said David J. Newman, retired chief of the National Cancer Institute's Natural Products Branch. "As a result of their work, the potential number of enediynes has significantly increased." Shen's method of strain prioritization and genome mining means a far more efficient use of resources involved in the discovery process, targeting only those strains that look to produce the most important natural compounds. "This study shows that the potential to rapidly discover new enediyne natural products from a large strain collection is within our reach," said TSRI Research Associate Xiaohui Yan, one of four first authors of the study. "We also show the feasibility of manipulating tiancimycin biosynthesis in vivo, which means that sufficient quantities of these precious natural products can be reliably produced by microbial fermentation for drug development and eventual commercialization." In addition to Shen and Yan, first authors of the study, "Strain Prioritization and Genome Mining for Enediyne Natural Products," include TSRI's Huiming Ge, Tingting Huang and Hindra. Other authors include Dong Yang, Qihui Teng, Ivana Crnovči?, Xiuling Li, Jeffrey D. Rudolf, Jeremy R. Lohman and Christoph Rader of TSRI; Yannick Gansemans and Filip Van Nieuwerburgh of Ghent University, Belgium; Yanwen Duan, Xiangcheng Zhu and Yong Huang of Xiangya International Academy of Translational Medicine, Central South University, China; Li-Xing Zhao and Yi Jiang of Yunnan University, China. The study was supported in part by the Chinese Ministry of Education (111 Project B08034), National High Technology Joint Research Program of China (grant 2011ZX09401-001), National High Technology Research and Development Program of China (grant 2012AA02A705), the National Institutes of Health (grants CA78747 and GM115575), the German Research Foundation and the Arnold and Mabel Beckman Foundation. The Scripps Research Institute (TSRI) is one of the world's largest independent, not-for-profit organizations focusing on research in the biomedical sciences. TSRI is internationally recognized for its contributions to science and health, including its role in laying the foundation for new treatments for cancer, rheumatoid arthritis, hemophilia, and other diseases. An institution that evolved from the Scripps Metabolic Clinic founded by philanthropist Ellen Browning Scripps in 1924, the institute now employs more than 2,500 people on its campuses in La Jolla, CA, and Jupiter, FL, where its renowned scientists--including two Nobel laureates and 20 members of the National Academy of Science, Engineering or Medicine--work toward their next discoveries. The institute's graduate program, which awards PhD degrees in biology and chemistry, ranks among the top ten of its kind in the nation. For more information, see http://www. .

Zhou S.,Central South University | Zhou S.,University of South China
Langmuir | Year: 2010

A classical free energy density functional, which is isomorphic to a usual effective hard sphere model + mean field approximation for tail contribution, is proposed for treatment of real fluids in inhomogeneous states. In the framework of the classical density functional theory (DFT), the present functional is applied to two representative model fluids, namely, a Lennard-Jones fluid and a hard core attractive Yukawa fluid, subject to influence of various external fields. A comprehensive comparison with simulation results and a detailed analysis show that the present functional holds simultaneously all of the desirable properties inherent in an excellent functional, such as high accuracy, computational simplicity, consistency with a hard wall sum rule, nonrecourse to use of adjustable parameter(s) and weighted densities, reproduction of bulk second-order direct correlation function (DCF) in bulk limit, and applicability to subcritical fluid phenomena. © 2010 American Chemical Society.

Bao R.,Central South University | Yi J.,Kunming University of Science and Technology
International Journal of Refractory Metals and Hard Materials | Year: 2014

In this paper, the densification and microstructural evolution of microwave fabricated WC-8Co composites were studied. Experimental results showed that shrinkage rate increased at 1275-1325 C. The shape of most WC grains was turned into truncated trigonal prism at 1300 C for 5 min. The apparent activation energy of WC coarsening in microwave prepared alloy was 84.48 Kcal/mol, which was much lower than that in vacuum sintering. Finally, the local liquid phase sintering mechanism of microwave sintered WC-Co cemented carbide based on the hot spots formation was proposed. © 2013 Elsevier Ltd.

Ye H.,Central South University | Jiang Z.-P.,New York University | Jiang Z.-P.,Beihang University | Gui W.,Central South University | Yang C.,Central South University
Automatica | Year: 2012

This paper investigates the problem of decentralized stabilization via saturated delayed feedback. First, a new class of saturated delayed feedback controllers is proposed for a class of single-input feedforward nonlinear systems. Then, this design scheme is generalized for the setting of decentralized feedforward systems using saturated time-delayed feedback. The stability analysis for the closed-loop decentralized systems is rather simple based on the proposed feedback structure. © 2011 Elsevier Ltd. All rights reserved.

Liu H.,Central South University | Tian H.-Q.,Central South University | Chen C.,Monash University | Li Y.-f.,Central South University
Renewable Energy | Year: 2010

Accurate forecasting of wind speed and wind power is important for the safety of renewable energy utilization. Compared with physical methods, statistical methods are usually simpler and more suitable for small farms. Based on the methods of wavelet and classical time series analysis, a new short-term forecasting method is proposed. Simulation upon actual time data shows that: (1) the mean relative error in multi-step forecasting based on the proposed method is small, which is better than classical time series method and BP network method; (2) the proposed method is robust in dealing with jumping data; and (3) the proposed method is applicable to both wind speed and wind power forecasting. © 2009 Elsevier Ltd. All rights reserved.

Zhou S.,Central South University | Zhou S.,University of South China
Journal of Chemical Physics | Year: 2010

A local self-consistent Ornstein-Zernike (OZ) integral equation theory (IET) is proposed to provide a rapid route for obtaining thermodynamic and structural information for any thermodynamically stable or metastable state points in the bulk phase diagram without recourse to traditional thermodynamic integration, and extensive NVT -Monte Carlo simulations are performed on a recently proposed honeycomb potential in three dimensions to test the theory's reliability. The simulated quantities include radial distribution function (rdf) and excess internal energy, pressure, excess chemical potential, and excess Helmholtz free energy. It is demonstrated that (i) the theory reproduces the rdf very satisfactorily only if the bulk state does not enter deep into a two phases coexistence region; (ii) the excess internal energy is the only one of the four thermodynamic quantities investigated amenable to the most accurate prediction by the present theory, and the simulated pressure is somewhat overestimated by the theoretical calculations, but the deviation tends to vanish along with rising of the temperature; (iii) using the structural functions from the present local self-consistent OZ IET, a previously derived local expression, due to the present author, achieves even a higher accuracy in calculating for the excess chemical potential than the exact virial pressure formula for the pressure, and the resulting excess Helmholtz free energy is in surprisingly same with the simulation results due to offset of the errors. Based on the above observations, it is suggested that it may be a good procedure to integrate the theoretical excess internal energy along the isochors to get the excess Helmholtz free energy, which is then fitted to a polynomial to be used for calculation of all of other thermodynamic quantities in the framework of the OZ IET. © 2010 American Institute of Physics.

Zhou S.,Central South University | Zhou S.,University of South China
Journal of Chemical Physics | Year: 2010

A new free energy density functional is advanced for general nonhard sphere potentials characterized by a repulsive core with a singular point at zero separation. The present functional is characterized by several features. (i) It does not involve with dividing the potentials into hard-sphere-like contribution and tail contribution in sharp contrast with usual effective hard sphere model+mean field approximation for tail contribution. (ii) It has no recourse to the use of weighted density and is computationally modest; it also does not resort to an equation of state and/or an excess Helmholtz free energy of bulk fluid over a range of density as input. Consequently, all of input information can be obtained by numerical solution of a bulk Ornstein-Zernike integral equation theory (OZ IET). Correspondingly, despite the use of bulk second-order direct correlation function (DCF) as input, the functional is applicable to the subcritical region. (iii) There is no any adjustable parameter associated with the present functional, and an effective hard sphere diameter entering the functional can be determined self-consistently and analytically once the input information, i.e., the second-order DCF and pressure of the coexistence bulk fluid, are obtained by the OZ IET. The present functional is applied to a core-softened fluid subject to varying external fields, and the density distributions predicted by the present functional are more self-consistent with available simulation results than a previous third-order+second-order perturbation density functional theory. © 2010 American Institute of Physics.

Hou M.,University of South China | Hou M.,Central South University | Han X.,University of South China
IEEE Transactions on Neural Networks | Year: 2010

It is well known that single hidden layer feedforward networks with radial basis function (RBF) kernels are universal approximators when all the parameters of the networks are obtained through all kinds of algorithms. However, as observed in most neural network implementations, tuning all the parameters of the network may cause learning complicated, poor generalization, overtraining and unstable. Unlike conventional neural network theories, this brief gives a constructive proof for the fact that a decay RBF neural network with n+1 hidden neurons can interpolate n+1 multivariate samples with zero error. Then we prove that the given decay RBFs can uniformly approximate any continuous multivariate functions with arbitrary precision without training. The faster convergence and better generalization performance than conventional RBF algorithm, BP algorithm, extreme learning machine and support vector machines are shown by means of two numerical experiments. © 2006 IEEE.

Tao H.,Central South University | Guo S.,Hunan Normal University | Ge T.,Fudan University | Kendrick K.M.,Babraham Institute | And 4 more authors.
Molecular Psychiatry | Year: 2013

It is increasingly recognized that we need a better understanding of how mental disorders such as depression alter the brain's functional connections to improve both early diagnosis and therapy. A new holistic approach has been used to investigate functional connectivity changes in the brains of patients suffering from major depression using resting-state functional magnetic resonance imaging (fMRI) data. A canonical template of connectivity in 90 different brain regions was constructed from healthy control subjects and this identified a six-community structure with each network corresponding to a different functional system. This template was compared with functional networks derived from fMRI scans of both first-episode and longer-term, drug resistant, patients suffering from severe depression. The greatest change in both groups of depressed patients was uncoupling of the so-called hate circuit involving the superior frontal gyrus, insula and putamen. Other major changes occurred in circuits related to risk and action responses, reward and emotion, attention and memory processing. A voxel-based morphometry analysis was also carried out but this revealed no evidence in the depressed patients for altered gray or white matter densities in the regions showing altered functional connectivity. This is the first evidence for the involvement of the hate circuit in depression and suggests a potential reappraisal of the key neural circuitry involved. We have hypothesized that this may reflect reduced cognitive control over negative feelings toward both self and others. © 2013 Macmillan Publishers Limited.

Liu H.,Central South University | Tian H.-Q.,Central South University | Chen C.,Monash University | Li Y.-F.,Central South University
International Journal of Electrical Power and Energy Systems | Year: 2013

Wind speed series show unsteady and nonlinear phenomena. The accurate forecast of wind speed is important for the safety of renewable energy utilization. Compared to the prediction models which use single algorithms, hybrid models always have higher accuracy. Based on the theories of Wavelet, classical time series analysis, genetic algorithm, particle swarm optimization and artificial neural networks, two hybrid forecasting frameworks [the Wavelet-Genetic Algorithm (GA)-Multilayer Perceptron (MLP) and the Wavelet-Particle Swarm Optimization (PSO)-Multilayer Perceptron (MLP)] are proposed to predict non-stationary wind speeds. Comparisons of forecasting performance using different algorithm combinations are provided to investigate the contribution of different components in those two hybrid frameworks. The results based on three experimental cases show that: (1) both of the two proposed hybrid forecasting frameworks are suitable for the diverse accuracy requirements in wind speed predictions, which can be applied to wind power systems; and (2) in both of the two hybrid frameworks, the contribution of the GA and the PSO components in improving the MLP are not statistically significant while that of the Wavelet component is statistically significant. © 2013 Elsevier Ltd. All rights reserved.

She S.,CAS Wuhan Institute of Rock and Soil Mechanics | Dong L.,Central South University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

This paper presents the statistics and analysis of academic papers published by Chinese authors in recent 30 years in rock mechanics and geotechnical engineering journals published in Chinese and English. The statistics and analysis also include academic papers citations in the key databases such as EI and SCI. The paper tries to summarize and analyze the situation and development of rock mechanics and geotechnical engineering in China in the last 30 years, especially in the last 10 years. The developments are mainly focused on rock strength and deformation theories, rock fracture and damage mechanics, rock dynamics and constitutive relationships, rock nonlinearity and rock multifield coupling, rock reinforcement and stability analysis. Finally, ten challenging issues are proposed in the field of rock mechanics and rock engineering.

Wu H.-N.,Beihang University | Wang J.-W.,Beihang University | Li H.-X.,City University of Hong Kong | Li H.-X.,Central South University
Automatica | Year: 2012

This paper investigates the problem of designing a distributed H∞ fuzzy controller with constraint for a class of nonlinear spatially distributed processes modeled by first-order hyperbolic partial differential equations (PDEs). The purpose of this paper is to design a distributed fuzzy state feedback controller such that the closed-loop PDE system is exponentially stable with a prescribed H∞ performance of disturbance attenuation, while the control constraint is respected. Initially, a TakagiSugeno (TS) hyperbolic PDE model is proposed to accurately represent the nonlinear PDE system. Then, based on the TS fuzzy PDE model, a distributed H∞ fuzzy controller design with constraint is developed in terms of a set of coupled differential/algebraic linear matrix inequalities (D/ALMIs) in space. Furthermore, a suboptimal distributed H∞ fuzzy controller with constraint is proposed to minimize the level of attenuation. The finite difference method in space and the existing linear matrix inequality (LMI) optimization techniques are employed to approximately solve the suboptimal fuzzy control design problem. Finally, the proposed design method is applied to the distributed control of a nonlinear system described by two coupled first-order hyperbolic PDEs to illustrate its effectiveness. © 2012 Elsevier Ltd. All rights reserved.

Gao J.,Beihang University | Yang Z.,Central South University | Li X.,Beihang University
Journal of Computational Physics | Year: 2012

In the implementation of spectral difference (SD) method, the conserved variables at the flux points are calculated from the solution points using extrapolation or interpolation schemes. The errors incurred in using extrapolation and interpolation would result in instability. On the other hand, the difference between the left and right conserved variables at the edge interface will introduce dissipation to the SD method when applying a Riemann solver to compute the flux at the element interface. In this paper, an optimization of the extrapolation and interpolation schemes for the fourth order SD method on quadrilateral element is carried out in the wavenumber space through minimizing their dispersion error over a selected band of wavenumbers. The optimized coefficients of the extrapolation and interpolation are presented. And the dispersion error of the original and optimized schemes is plotted and compared. An improvement of the dispersion error over the resolvable wavenumber range of SD method is obtained. The stability of the optimized fourth order SD scheme is analyzed. It is found that the stability of the 4th order scheme with Chebyshev-Gauss-Lobatto flux points, which is originally weakly unstable, has been improved through the optimization. The weak instability is eliminated completely if an additional second order filter is applied on selected flux points. One and two dimensional linear wave propagation analyses are carried out for the optimized scheme. It is found that in the resolvable wavenumber range the new SD scheme is less dispersive and less dissipative than the original scheme, and the new scheme is less anisotropic for 2D wave propagation. The optimized SD solver is validated with four computational aeroacoustics (CAA) workshop benchmark problems. The numerical results with optimized schemes agree much better with the analytical data than those with the original schemes. © 2012 Elsevier Inc.

Muzhou H.,University of South China | Muzhou H.,Central South University | Xuli H.,University of South China
Applied Soft Computing Journal | Year: 2011

For the multidimensional continuous function, using constructive feedforward wavelet RBF neural network, we prove that a wavelet RBF neural network with n + 1 hidden neurons can interpolate n + 1 multidimensional samples with zero error. Then we prove they can uniformly approximate any continuous multidimensional function with arbitrary precision. This method can avoid the defects of conventional neural networks using learning algorithm in practice. The correctness and effectiveness are verified through four numeric experiments. © 2010 Elsevier B.V. All rights reserved.

Zhang X.,Kunming University of Science and Technology | Tang X.,Central South University
Advanced Nonlinear Studies | Year: 2013

In this paper, some existence theorems are obtained for non-constant periodic solutions of second order Hamiltonian system involving the p-Laplacian by using the linking method. Our results generalize and improve several known results in the literature.

Gudehus G.,Karlsruhe Institute of Technology | Jiang Y.,Central South University | Liu M.,University of Tübingen
Granular Matter | Year: 2011

The recently published theory named Granular Solid Hydrodynamics (GSH) is outlined, supported and quantified with arguments from physics as well as soil mechanics. Seismodynamic equilibria serve to introduce a granular temperature T g and a related entropy s g, both with gradients. The evolution equations of GSH are first presented without gradients, parameters are proposed as functions of T g and estimated. Constant stretching leads to nearly hypoplastic relations for a certain range of T g . Cyclic deformations lead to pulsating T g and to asymptotic cycles of stress and density. State cycles are also attained with additionally imposed isochoric deformations (ratcheting). Similar attractors can be obtained with elastoplastic or hypoplastic relations with hidden variables. GSH is then presented with gradients and boundary conditions. Consequences for stabilization and destabilization are outlined by means of the total energy and with driven attractors. Conclusions and an outlook indicate that GSH is going to become a powerful unified concept. © 2010 Springer-Verlag.

Chen M.-S.,Central South University | Chen M.-S.,State Key Laboratory of High Performance Complex Manufacturing | Lin Y.C.,Central South University | Lin Y.C.,State Key Laboratory of High Performance Complex Manufacturing
International Journal of Plasticity | Year: 2013

Large forgings are the essential parts of some nuclear, electrical power generation, rolling mill equipments. Generally, they are directly obtained by forging the large ingots containing some void defects. In this study, the evolution mechanisms for the spherical or spheroidal voids during hot working are investigated by the numerical simulations and experiments. The effects of the initial void size, aspect ratio and positions on the void evolution were discussed. The results show that the closure process of voids can be divided into two stages. i.e.; when the deformation degree is relatively small, the void retains spheroidal. However, the void will not be spheroidal when the deformation degree is relatively large. The changes of void aspect ratio are slightly affected by the void size, but greatly by the initial aspect ratio and position of voids. It also suggests that the strain and stress fields around voids are the key factors influencing the evolution of void aspect ratio. The increase of effective strain contributes to the changes of void aspect ratio. Considering the effects of stress and strain fields on the void evolution, a void aspect ratio evaluation index, which is defined as a function of the stress deviator, effective strain and effective stress, is proposed to describe the changes of void aspect ratio. Based on the results from finite element simulation, a theoretical model is established to predict the changes of void aspect ratio in large forgings during hot working. A good agreement between experimental and simulated results indicates that the proposed void aspect ratio evaluation index and theoretical model can give an accurate description of the void evolution. © 2013 Elsevier Ltd. All rights reserved.

Liu H.,Central South University | Liu Y.,Tsinghua University | Li J.,Tsinghua University
Physical Chemistry Chemical Physics | Year: 2010

Ionic liquids (IL) are widely used in electrochemistry due to their excellent properties such as good ionic conductivity, wide electrochemical potential window, high viscosity, high thermal stability, wide liquid range and tunable solvent properties. In electrochemistry, the performance of an electrochemical system is dependent on the properties of the interface at the IL/electrode. This review presents the surface electrochemistry in ILs, and the interfacial structures of IL/electrode and heterogeneous electron-transfer kinetics are detailed. Finally, the updated researches on the electrochemical applications of ILs such as electrode deposition, electrosynthesis, electrocatalysis, electrochemical biosensing, electrochemical capacitor and lithium batteries are demonstrated. © 2010 the Owner Societies.

Yang X.,Hunan Normal University | Xua D.,Hunan Normal University | Zhang H.,Central South University
Journal of Computational Physics | Year: 2013

In this paper, we study a novel numerical scheme for the fourth order partial integro-differential equation with a weakly singular kernel. In the time direction, a Crank-Nicolson time-stepping is used to approximate the differential term and the product trapezoidal method is employed to treat the integral term, and the quasi-wavelets numerical method for space discretization. Our interest in the present paper is a continuation of the investigation in Yang et al. [33], where we study discretization in time by using the forward Euler scheme. The comparisons of present results with the previous ones show that the present scheme is more stable and efficient for numerically solving the fourth order partial integrodifferential equation with a weakly singular kernel. We also tested the method proposed on several one and two dimensional problems with very promising results. Besides, in order to demonstrate the power of the quasi-wavelets method in comparison with standard discretization methods we also consider the high-frequency oscillation problems with the integro-differential term. ©2012 Elsevier Inc.

Xiao Z.,University of Nebraska - Lincoln | Bi C.,University of Nebraska - Lincoln | Shao Y.,University of Nebraska - Lincoln | Dong Q.,University of Nebraska - Lincoln | And 6 more authors.
Energy and Environmental Science | Year: 2014

We report on an interdiffusion method to fabricate pin-hole free perovskite films using a low temperature (<105 °C) solution process. A high efficiency of 15.4%, with a fill factor of ∼80%, was achieved for the devices under one sun illumination. The interdiffusion method results in high device yield, with an efficiency of above 14.5% for more than 85% of the devices. This journal is © the Partner Organisations 2014.

Huang Y.,Central South University | Veronis G.,Louisiana State University | Min C.,Shenzhen University
Optics Express | Year: 2015

We design a non-parity-Time-symmetric plasmonic waveguidecavity system, consisting of two metal-dielectric-metal stub resonators side coupled to a metal-dielectric-metal waveguide, to form an exceptional point, and realize unidirectional reflectionless propagation at the optical communication wavelength. The contrast ratio between the forward and backward reflection almost reaches unity. We show that the presence of material loss in the metal is critical for the realization of the unidirectional reflectionlessness in this plasmonic system. We investigate the realized exceptional point, as well as the associated physical effects of level repulsion, crossing and phase transition. We also show that, by periodically cascading the unidirectional reflectionless plasmonic waveguide-cavity system, we can design a wavelength-scale unidirectional plasmonic waveguide perfect absorber. Our results could be potentially important for developing a new generation of highly compact unidirectional integrated nanoplasmonic devices. © 2015 Optical Society of America.

Huang Y.,Central South University | Min C.,Shenzhen University | Dastmalchi P.,Louisiana State University | Veronis G.,Louisiana State University
Optics Express | Year: 2015

We introduce slow-light enhanced subwavelength scale refractive index sensors which consist of a plasmonic metal-dielectric-metal (MDM) waveguide based slow-light system sandwiched between two conventional MDM waveguides. We first consider a MDM waveguide with small width structrue for comparison, and then consider two MDM waveguide based slow light systems: a MDM waveguide side-coupled to arrays of stub resonators system and a MDM waveguide side-coupled to arrays of double-stub resonators system. We find that, as the group velocity decreases, the sensitivity of the effective index of the waveguide mode to variations of the refractive index of the fluid filling the sensors as well as the sensitivities of the reflection and transmission coefficients of the waveguide mode increase. The sensing characteristics of the slow-light waveguide based sensor structures are systematically analyzed. We show that the slowlight enhanced sensors lead to not only 3.9 and 3.5 times enhancements in the refractive index sensitivity, and therefore in the minimum detectable refractive index change, but also to 2 and 3 times reductions in the required sensing length, respectively, compared to a sensor using a MDM waveguide with small width structure. © 2015 Optical Society of America.

Yang Y.,Guangdong Ocean University | Li M.,Central South University
International Journal of Thermal Sciences | Year: 2014

A composite-medium line-source model has been recently developed for modeling short-time thermal processes of borehole ground heat exchangers. The composite-medium line-source model is attractive for applications where the short-term or high-frequency responses of borehole ground heat exchangers are important. In this paper, the short-time performance of this analytical model is examined in depth by comparing it with a two-dimensional finite volume model. The numerical model can address the heat capacity of circulating water by using a novel time-varying boundary condition on the inner walls of the U-shaped tube, in addition to the heat capacities of U-shaped tube and grouting material. Both the numerical and the analytical composite-medium models are validated using an independent sandbox experiment. Comparisons between the two models are also made for different parameters, including heating rate, the spacing of the U-tube legs, thermal properties, and borehole radius. Overall, the composite-medium line-source model gives the virtually same results as the numerical model except for the first several minutes: the analytical solution overestimates temperature responses during the first 3 min, which is caused by the line-source assumption ignoring the heat capacities of the fluid and the U-shaped pipe. © 2014 Elsevier Masson SAS. All rights reserved.

Zhang Z.,Hunan Normal University | Lin J.,Central South University
Asian Journal of Animal and Veterinary Advances | Year: 2012

The main purpose of this study was to examine the effects of Achyranthes bidentata Polysaccharides (ABP) on physical fatigue. One hundred and forty four mice were randomly divided into 4 groups: one control group and three ABP treatment groups. The control group was given isotonic sodium chloride solution and the treatment groups were given different doses of ABP (50, 100, 200 mg kg-1) by giving once a day for 28 days. After 28 days, the forced swimming test was performed and the biochemical parameters related to fatigue were examined. The results suggested that ABP had clear anti-physical fatigue effects which could extend the exhaustive swimming time of the mice, as well as increases the liver glycogen and muscle glycogen contents and decreases the blood lactic acid and blood urea nitrogen contents. © 2012 Academic Journals Inc.

Xie Z.,Central South University | Chang C.,Thomas Jefferson University | Zhou Z.,Central South University
Clinical Reviews in Allergy and Immunology | Year: 2014

Autoimmune type 1 diabetes is characterized by selective destruction of insulin-secreting beta cells in the pancreas of genetically susceptible individuals. The mechanisms underlying the development of type 1 diabetes are not fully understood. However, a widely accepted point is that type 1 diabetes is caused by a combination of genetic and environmental factors. Although most type 1 diabetes patients do not have a family history, genetic susceptibility does play a vital role in beta cell autoimmunity and destruction. Human leukocyte antigen (HLA) regions are the strongest genetic determinants, which can contribute 40–50 % of the genetic risk to type 1 diabetes. Other genes, including INS also contribute to disease risk. The mechanisms of the susceptible genes in type 1 diabetes may relate to their respective roles in antigen presentation, beta cell autoimmunity, immune tolerance, and autoreactive T cell response. Environmental susceptibility factors also contribute to the risk of developing type 1 diabetes. From an epigenetic standpoint, the pathologic mechanisms involved in the development of type 1 diabetes may include DNA methylation, histone modification, microRNA, and molecular mimicry. These mechanisms may act through regulating of gene expression, thereby affecting the immune system response toward islet beta cells. One of the characteristics of type 1 diabetes is the recognition of islet autoantigens by autoreactive CD4+ and CD8+ T cells and autoantibodies. Autoantibodies against islet autoantigens are involved in autoantigen processing and presentation by HLA molecules. This review will mainly focus on the molecular mechanism by which genetic, epigenetic, and environmental factors contribute to the risk of type 1 diabetes. © 2014, Springer Science+Business Media New York.

Chai W.,University of Virginia | Zhang X.,University of Virginia | Zhang X.,Central South University | Barrett E.J.,University of Virginia | Liu Z.,University of Virginia
Diabetes | Year: 2014

Glucagon-like peptide 1 (GLP-1) acutely recruits muscle microvasculature, increases muscle delivery of insulin, and enhances muscle use of glucose, independent of its effect on insulin secretion. To examine whether GLP-1 modulates muscle microvascular and metabolic insulin responses in the setting of insulin resistance, we assessed muscle microvascular blood volume (MBV), flow velocity, and blood flow in control insulin-sensitive rats and rats made insulin-resistant acutely (systemic lipid infusion) or chronically (high-fat diet [HFD]) before and after a euglycemic-hyperinsulinemic clamp (3 mU/kg/min) with or without superimposed systemic GLP-1 infusion. Insulin significantly recruited muscle microvasculature and addition of GLP-1 further expanded muscle MBV and increased insulin-mediated glucose disposal. GLP-1 infusion potently recruited muscle microvasculature in the presence of either acute or chronic insulin resistance by increasing muscle MBV. This was associated with an increased muscle delivery of insulin and muscle interstitial oxygen saturation. Muscle insulin sensitivity was completely restored in the presence of systemic lipid infusion and significantly improved in rats fed an HFD. We conclude that GLP-1 infusion potently expands muscle mi-crovascular surface area and improves insulin's metabolic action in the insulin-resistant states. This may contribute to improved glycemic control seen in diabetic patients receiving incretin-based therapy. © 2014 by the American Diabetes Association.

Tan Y.,Shanxi Medical University | Zhang H.,Shanxi Medical University | Xiao E.-H.,Central South University
Clinical Radiology | Year: 2013

Aim: To evaluate the dynamic computed tomography (CT), magnetic resonance imaging (MRI), and clinicopathological characteristics of perivascular epithelioid cell tumours (PEComas), thus improving the diagnosis of the tumour. Materials and methods: A retrospective analysis was undertaken of the dynamic CT, MRI, and clinicopathological characteristics of 32 PEComas diagnosed at histopathology during the period 1 January 2005 to 1 March 2012 at two hospitals. Results: The age of the patients ranged from 14-80 years (mean 43.3 years). There were more women in this group (19/32). Solitary tumours were identified in kidney (n = 16), liver (n = 7), gynaecological organs (n = 2), retroperitoneal soft tissue (n = 2), lung (n = 2), palate (n = 1), left groin (n = 1). One patient had multiple tumours in the liver, kidney, and retroperitoneal soft tissue. Dynamic CT (32 cases) and MRI (15 cases) demonstrated tumours that were of low density or hypointense on T1-weighted imaging (WI) and hyperintense on T2WI; some were isodense with fat (CT: 10/32; MRI: 6/15). The tumours usually had well-defined borders and were of a regular shape (CT: 26/32; MRI: 12/15). Tumour diameters ranged from 1.5-18 cm (mean 5.1 cm). Most tumours (CT: 21/32, MRI: 10/15) enhanced heterogeneously and significantly on arterial and venous phases. Tumours appeared slightly hypodense on delayed CT imaging, although some (6/32) had delayed enhancement. The expression rate of HMB-45 (human melanoma black monoclonal antibody) was 100% (32/32). Histological classification in 22 cases (22/32) was epithelioid angiomyolipoma (AML), three (3/32) were clear cell "sugar" tumours (CCSTs), two (2/32) were lymphangioleiomyomatosis (LAM), and two (2/32) were clear cell myomelanocytic tumours of the falciform ligament/ligamentum teres (CCMMT). Three tumours did not have a specific classification. Conclusion: Knowledge of dynamic CT, MRI, and clinicopathological characteristics could help improve the diagnosis of PEComa. © 2012 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Zhang L.,Shandong University of Technology | Li T.,Shandong University of Technology | Xu X.,Central South University
Knowledge-Based Systems | Year: 2014

Group decision making with consensus requirement is the process of reaching group consensus, ranking the feasible alternatives and selecting the best one. In this paper, we develop a methodology for fuzzy group decision making with group consensus. Firstly, each expert makes his/her judgement on each alternative with respect to multiple criteria by the intuitionistic fuzzy sets, the group preference vectors for each alternative are calculated by the formula. Secondly, the similarity measure between two intuitionistic fuzzy sets is defined to compute each expert's decision deviation, a threshold value is used to determine the decision deviation whether be acceptable. Then, based on the expert's group consensus decision information, the group matrix is obtained by weighted similarity measure. Using the ordered weight operator, the order of the alternatives is got and the best one can be easily selected. Finally, we apply our method to facility location selection problem and the other group consensus example in [3] to verify our methodology's feasibility and effectiveness. © 2013 Elsevier B.V. All rights reserved.

Zhou H.,Central South University | Ying H.,Wayne State University
IEEE Transactions on Fuzzy Systems | Year: 2013

Type-2 (T2) fuzzy controllers are emerging as the related T2 fuzzy logic, and algorithms have recently been advancing rapidly. At present, a T2 fuzzy controller is viewed and used as a black-box function generator that produces a desired nonlinear mapping between the input and output of the controller (we call the mapping analytical structure). The mathematical expression of the analytical structure, however, is not explicitly known to the controller designer. This is in sharp contrast with the analytical structure of a conventional controller, which is not only always explicitly known, but serves as a starting point for system analysis and design. Obviously, the knowledge of a T2 fuzzy controller's analytical structure can have significant benefits. They include 1) understanding more precisely how the controller works in the same sense as we understand how a conventional controller (e.g., the PID controller) functions; 2) making T2 fuzzy control more acceptable to safety-critical fields such as biomedicine; 3) taking advantage of the well-developed nonlinear control theory to develop better analysis and design methods for T2 control systems (e.g., less conservative system stability criteria); and 4) permitting rigorous comparative exploration on differences between the T2 and type-1 (T1) fuzzy controllers and their relative merits and pitfalls (e.g., performance and structural complexity). In this paper, we develop an innovative technique which is capable of deriving the analytical structure for a wide class of interval T2 Mamdani fuzzy controllers. The configuration of the controllers is typical and is substantially more general than the related efforts in the literature. It uses any number and types of interval T2 input fuzzy sets, any number and types of general or interval T2 output fuzzy sets, arbitrary fuzzy rules, Zadeh and operator, Karnik-Mendel center-of-sets type reducer, and the centroid defuzzifier. We show in detail how the derivation method works in a general setting and provide the analytical structure of an example T2 controller as well. In addition, we utilize the method to prove that a subset of the T2 fuzzy controllers are the sum of two nonlinear PI (or PD) controllers, each of which has a variable proportional gain and a variable integral gain (or derivative gain) plus a variable offset if and only if the input fuzzy sets are piecewise linear (e.g., triangular and/or trapezoidal). The sum of the two nonlinear PI (or PD) controllers is a new discovery relative to the current literature. © 1993-2012 IEEE.

Zeng H.-B.,Hunan University of Technology | He Y.,Wuhan University | Wu M.,Wuhan University | She J.,Central South University | She J.,Tokyo University of Technology
IEEE Transactions on Automatic Control | Year: 2015

The free-weighting matrix and integral-inequality methods are widely used to derive delay-dependent criteria for the stability analysis of time-varying-delay systems because they avoid both the use of a model transformation and the technique of bounding cross terms. This technical note presents a new integral inequality, called a free-matrix-based integral inequality, that further reduces the conservativeness in those methods. It includes well-known integral inequalities as special cases. Using it to investigate the stability of systems with time-varying delays yields less conservative delay-dependent stability criteria, which are given in terms of linear matrix inequalities. Two numerical examples demonstrate the effectiveness and superiority of the method. © 1963-2012 IEEE.

Liu X.,Central South University | Wu S.,Wuhan University of Technology
Construction and Building Materials | Year: 2011

The mechanical and electrical properties of graphite and carbon fiber modified asphalt concrete were measured in this paper through the indirect tensile test. The experimental results indicate that the mechanical properties of asphalt mixture are influenced by the addition of conductive component like graphite and carbon fiber, When the graphite content increased from 0 to 22 vol.%, Marshall stability decreased from 12.8 kN to 9.43 kN and residual stability from 91.1% to 87.2%. Rutting dynamic stability decreased from 3318 times/mm to 2619 times/mm. After adding the carbon fiber, when the carbon fiber content increased from 0 to 2 vol.%, their Marshall stability and residual stability increased from 12.8 kN to 13.5 kN and residual stability from 91.1% to 92.7%. Rutting dynamic stability increased from 3318 times/mm to 3403 times/mm. When modified through combination effect of graphite and carbon fiber mixed fillers, the mechanical performance and electrical property were improved greatly, their Marshall stability and residual stability has increased from 9.43 kN to 12.1 kN and residual stability from 87.2% to 89.2%. Rutting dynamic stability increased from 2619 times/mm to 3292 times/mm. Furthermore, the resilient modulus is influenced by the addition of graphite, the value of resilient modulus is as much as that of the original, it is 90% when graphite is 30 vol.% and is 70% when graphite is 45 vol.%. The electrical resistance increases reversibly with increasing tensile strain either under dynamic indirect tensile testing or static indirect tensile testing, graphite and carbon fiber modified asphalt concretes are effective for the self-monitoring of strain. It is foreseen that the strain-stress self monitoring is valuable for weighing, traffic monitoring, border monitoring and structural vibration control. © 2010 Elsevier Ltd. All rights reserved.

Mao X.,Central South University | Tay G.H.,The Prince Charles Hospital | Godbolt D.B.,The Prince Charles and Holy Spirit Hospital | Crawford R.W.,The Prince Charles Hospital | Crawford R.W.,Queensland University of Technology
Journal of Arthroplasty | Year: 2012

The incidence of pseudotumor formation has been reported to be 1% in patients with metal-on-metal resurfacing arthroplasties. This complication is not exclusive to these patients. We report a case of pseudotumor formation secondary to femoral head-neck corrosion after a metal-on-polyethylene uncemented total hip arthroplasty. © 2012 Elsevier Inc.

Liu G.P.,University of South Wales | Liu G.P.,Central South University
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2010

This brief studies the predictive controller design of networked systems with communication delay and data loss. A networked predictive control scheme is employed to compensate for communication delay and data loss actively rather than passively. Based on analysis of the closed-loop networked predictive control systems, a design strategy of the predictive controller is proposed. The designed predictive controller can achieve the desired control performance and also guarantee the system stability. A numerical example demonstrates the compensation for communication delay and data loss in networked systems using the proposed predictive controller design strategy. © 2010 IEEE.

Liang R.,Tsinghua University | Liang R.,Central South University | Cao H.,Tsinghua University | Qian D.,Central South University
Chemical Communications | Year: 2011

MoO 3 nanowires synthesized using a biomolecule-assisted hydrothermal approach showed excellent adsorption ability for the removal of RhB and were also shown to be excellent pseudocapacitor materials. © 2011 The Royal Society of Chemistry.

Li T.,Central South University | Yang M.,Central South University | Li H.,University of Jinan
Journal of Electroanalytical Chemistry | Year: 2011

The synergistic effect between graphene sheet (GS) and cobalt hexacyanoferrate nanoparticle (CoNP) was investigated, and showed that the electroactivity of CoNP was greatly enhanced in the presence of GS due to great electron-transfer ability of GS. A label-free electrochemical immunosensor for the sensitive detection of prostate specific antigen (PSA) was fabricated. Molecule 1-pyrenebutanoic acid, succinimidyl ester (PBSE) was adsorbed onto GS and the colloidal solution containing GS-CoNP-PBSE was added onto glassy carbon electrode surface to form stable thin film with high electroactivity. After anti-PSA antibody was conjugated onto PBSE, the modified electrode could be used as an amperometric immunosensor for the detection of PSA. The specific antibody-antigen immunocomplex formed on the electrode resulted in the decrease of amperometric signal of the electrode. The amperometric signal decreased linearly with PSA concentration in the range of 0.02-2 ng/mL with a low detection limit of 0.01 ng/mL. The immunosensor has the advantages of high sensitivity, good selectivity and stability, and could become a promising technique for cancer marker detection. © 2011 Elsevier B.V. All rights reserved.

Wu J.,Central South University | Yin X.,Sun Yat Sen University
Computers and Mathematics with Applications | Year: 2011

This paper deals with an M/G/1 retrial queue with negative customers and non-exhaustive random vacations subject to the server breakdowns and repairs. Arrivals of both positive customers and negative customers are two independent Poisson processes. A breakdown at the busy server is represented by the arrival of a negative customer which causes the customer being in service to be lost. The server takes a vacation of random length after an exponential time when the server is up. We develop a new method to discuss the stable condition by finding absorb distribution and using the stable condition of a classical M/G/1 queue. By applying the supplementary variable method, we obtain the steady-state solutions for both queueing measures and reliability quantities. Moreover, we investigate the stochastic decomposition law. We also analyse the busy period of the system. Some special cases of interest are discussed and some known results have been derived. Finally, an application to cellular mobile networks is provided and the effects of various parameters on the system performance are analysed numerically. © 2011 Elsevier Ltd. All rights reserved.

He Y.,Central South University | Zhang Y.,Central South University | Wu M.,Central South University | She J.-H.,Tokyo University of Technology
International Journal of Robust and Nonlinear Control | Year: 2010

This paper is concerned with delay-dependent exponential stability for stochastic Markovian jump systems with nonlinearity and time-varying delay. An improved exponential stability criterion for stochastic Markovian jump systems with nonlinearity and time-varying delay is proposed without ignoring any terms by considering the relationship among the time-varying delay, its upper bound and their difference, and using both Itô's differential formula and Lyapunov stability theory. A numerical example is given to illustrate the effectiveness and the benefits of the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.

Liao F.,Central South University | Liao F.,Xiangnan University | Tang X.H.,Central South University | Zhang J.,Central South University
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2015

This paper is concerned with the following elliptic system:(Formula presented.),where V and W are 1-periodic in x, and W(x,s,t) is super-quadratic in (Formula presented.) for some a, b > 0. By using a generalized linking theorem established by Li and Szulkin, we are able to obtain the existence of nontrivial solutions under some more generic assumptions on the nonlinearity. © 2014, Springer Basel.

Yang X.,Hunan Normal University | Zhang H.,Central South University | Xu D.,Hunan Normal University
Journal of Computational Physics | Year: 2014

The aim of this paper is to develop a novel numerical techniques for the solution of the two-dimensional fractional sub-diffusion equation. The proposed technique is based on orthogonal spline collocation (OSC) method in space and a finite difference method (FDM) in time. Stability and convergence of the proposed method are rigorously discussed and theoretically proven. We present the results of numerical experiments in one and two space variables, which confirm the predicted convergence rates and exhibit optimal accuracy in various norms. © 2013 Elsevier Inc.

Wu M.,Central South University | Zhou L.,Central South University | She J.,Central South University | She J.,Tokyo University of Technology
IEEE Transactions on Automatic Control | Year: 2011

This technical note deals with the problem of designing a robust observer-based repetitive-control system that provides a given H ∞ disturbance attenuation performance for a class of plants with time-varying structured uncertainties. A continuous-discrete two-dimensional model is built that accurately describes the features of repetitive control, thereby enabling the control and learning actions to be preferentially adjusted. A sufficient condition for the repetitive-control system to have a disturbance-attenuation bound in the H∞ setting is given in terms of a linear matrix inequality (LMI). It yields the parameters of the repetitive controller and the state observer. Finally, a numerical example demonstrates the effectiveness of the method, whose main advantage is the easy, preferential adjustment of control and learning through the tuning of two parameters in the LMI-based condition. © 2006 IEEE.

Jiang X.,Central South University | Jiang X.,University of Tennessee at Knoxville | Ma Z.J.,University of Tennessee at Knoxville | Ren W.-X.,Central South University
Computer-Aided Civil and Infrastructure Engineering | Year: 2012

A new method for cracks detection in beams is proposed by using the slope of the mode shape to detect cracks, and by introducing the angle coefficients of complex continuous wavelet transform. This study is aimed at detecting the location of the nonpropagating transverse crack. A series of beams with cracks that are simulated by rotational springs with equivalent stiffness are analyzed. The mode shape and the slope of this lumped crack model are calculated. Through complex continuous wavelet transform of the slope of the mode shape using Complex Gaus1 wavelet (CGau1), the locations of cracks are detected from the modulus line and the angle line of wavelet coefficients. By comparison, the singularity is much more apparent from the angle line of complex continuous wavelet transform. This demonstrates that the proposed method outperforms the existing method of wavelet transform of the mode shape with real wavelets. Also, this method can detect cracks in beams with different boundary conditions. The influence of crack locations and crack depth on crack detection is discussed. Finally, the noise effect is studied. Through the multiscale analysis, the locations of cracks may be detected from the angle of wavelet coefficients. © 2011 Computer-Aided Civil and Infrastructure Engineering.

Liu T.,Tsinghua University | Zhao C.,Central South University
Soil Dynamics and Earthquake Engineering | Year: 2013

Since the generalized transfer matrix method overcomes the intrinsic instability of the Thomson-Haskell transfer matrix method for both high frequencies and/or thick layers, it can produce stable and accurate solutions for the dynamic analysis of viscoelastic media as well as anisotropic media. This paper extends the generalized transfer matrix method to the dynamic analysis of multilayered poroelastic media. Main improvements include the presentation of the concisely explicit general solutions for the dynamic analysis of multilayered poroelastic media and the derivation of an analytical inversion of 8×8 order layer matrix corresponding to the general solutions. The explicit solutions are valid for the dynamic analysis of one-dimensional, two-dimensional and three-dimensional poroelastic medium problems. In addition, an efficient recursive scheme is proposed for accurate determination of the equivalent interface sources for multilayered poroelastic media due to excitation by a source at an arbitrary depth. For the dynamic analysis of multilayered poroelastic media, the generalized transfer matrix method recursively transfers both the interface stiffness matrix and equivalent source starting from the bottom half space to the top layer, without resort to the numerical solution of the assembled global equations as the exact stiffness matrix method does. While keeping the simplicity of the Thomson-Haskell transfer matrix method, the generalized transfer matrix method is both accurate and stable. The related numerical examples have demonstrated that the generalized transfer matrix method is an alternative approach to conducting the dynamic analysis of multilayered poroelastic media. © 2012 Elsevier Ltd.

Tong J.,Thomas Jefferson University | Tong J.,Central South University | Huang C.,Thomas Jefferson University | Bi F.,Thomas Jefferson University | And 6 more authors.
EMBO Journal | Year: 2013

Mutation of Tar DNA-binding protein 43 (TDP-43) is linked to amyotrophic lateral sclerosis. Although astrocytes have important roles in neuron function and survival, their potential contribution to TDP-43 pathogenesis is unclear. Here, we created novel lines of transgenic rats that express a mutant form of human TDP-43 (M337V substitution) restricted to astrocytes. Selective expression of mutant TDP-43 in astrocytes caused a progressive loss of motor neurons and the denervation atrophy of skeletal muscles, resulting in progressive paralysis. The spinal cord of transgenic rats also exhibited a progressive depletion of the astroglial glutamate transporters GLT-1 and GLAST. Astrocytic expression of mutant TDP-43 led to activation of astrocytes and microglia, with an induction of the neurotoxic factor Lcn2 in reactive astrocytes that was independent of TDP-43 expression. These results indicate that mutant TDP-43 in astrocytes is sufficient to cause non-cell-autonomous death of motor neurons. This motor neuron death likely involves deficiency in neuroprotective genes and induction of neurotoxic genes in astrocytes. © 2013 European Molecular Biology Organization.

Irfan I.,University of Rochester | James Turinske A.,University of Wisconsin - Oshkosh | Bao Z.,Stanford University | Gao Y.,University of Rochester | Gao Y.,Central South University
Applied Physics Letters | Year: 2012

We report substantial work function (WF) recovery of air exposed molybdenum oxide thin films with vacuum annealing. We observed a sharp reduction in the MoO x WF (from 6.8 eV to 5.6 eV) as well as a very thin layer of oxygen rich adsorbate on the MoO x film after an hour of air exposure. The WF of the exposed MoO x film started to gradually recover with increasing annealing temperature in vacuum, and the saturation in the WF recovery was observed at 450 °C with WF ∼6.4 eV. We further studied the interface formation between the annealed MoO x and copper phthalocyanine (CuPc). The highest occupied molecular orbital (HOMO) level of CuPc was observed to be almost pinned to the Fermi level, strongly suggesting the possibility of efficient hole injection with the vacuum annealed MoO x film. © 2012 American Institute of Physics.

Wang K.,Tsinghua University | Zheng Z.,Tsinghua University | Li Y.,Tsinghua University | Liu K.,Central South University | Shang J.,Central South University
IEEE Transactions on Industrial Electronics | Year: 2013

The five-level active neutral-point (NP)-clamped (ANPC) converter is a newly emerging topology which can overcome the drawbacks of traditional NP-clamped and flying-capacitor multilevel converters. This paper presents a comprehensive theoretical analysis of the NP potential balancing issue and demonstrates that the NP potential can be naturally balanced under ideal and steady conditions. An NP potential balancing method based on zero-sequence voltage injection is presented. By calculating the average NP currents of all key zero-sequence voltages, the most appropriate zero-sequence voltage is selected to generate the demanded NP current, which can also limit the switching frequency of the series-connected insulated-gate bipolar transistors to the fundamental frequency. A three-phase five-level ANPC inverter prototype is built up, and both steady and dynamic experimental results are presented to verify the validity of this method. © 2012 IEEE.

Lu X.-F.,Jiangnan University | Lu X.-F.,Central South University | Xiao P.,Central South University
Carbon | Year: 2013

Silicon carbide nanofibers (SiCNFs) used as the second reinforcements of carbon/carbon composites were grown radially on the carbon fiber surface. The microstructure of SiCNFs and their effects on the microstructure and flexural properties of C/C composites were investigated. Results show that there are many defects such as twin crystals and stacking faults in SiCNFs which were grown by catalytic chemical vapor deposition. During the same process, the skin region of carbon fiber has changed. Several SiC layers are formed and the arrangement of the graphite layers around SiC layers is more orderly. In the next chemical vapor infiltration, due to the induction of SiCNFs, the middle textural pyrocarbon were formed firstly and then is the high textural pyrocarbon. The existence of SiCNFs also contributes to the three-phase interface between pyrocarbon, SiCNFs and carbon fibers, resulting in a good bond between carbon fiber and matrix. Those structural changes lead the better flexural properties of SiCNF-C/C composites compared with C/C composites. © 2013 Elsevier Ltd.

Wang Z.Q.,Xiangtan University | Wang Z.Q.,Central South University | Zhou N.J.,Central South University | Guo J.,Central South University | Wang X.Y.,Central South University
Energy | Year: 2012

The paper presented a working fluid selection and parametric optimization using a multi-objective optimization model by simulated annealing algorithm. The screening criteria considered included heat exchanger area per unit power output (A/W net) and heat recovery efficiency (F{cyrillic}). The independent parameters are the evaporation and condensation pressures, working fluid and cooling water velocities in tubes. A comparison of optimized results for 13 working fluids shows that boiling temperature of working fluids will greatly affect the optimal evaporating pressure. R123 is the best choice for the temperature range of 100-180°C and R141b is the optimal working fluid when the temperature higher than 180°C. When the exhaust temperature ranges from 100°C to 220°C, the optimal pinch point at evaporator is about 15°C. Economic characteristic of system decreases rapidly with heat source temperature decrease. When the heat source temperature is lower than 100°C, ORC technology is uneconomical. © 2012 Elsevier Ltd.

Chen C.,Xiangtan University | Zhang J.,Central South University
International Journal of Geomechanics | Year: 2013

Developing reliable and versatile constitutive models for geomaterials has been a challenging task for nonlinear finite-element analysis of geotechnical engineering systems.This paper is mainly concerned with the elastoplastic constitutive relationship of unbound granular materials under various stress paths. The fuzzy set plasticity theory has been developed to account for the nonlinear soil stress-strain behavior. The theory in many ways resembles the bounding surface plasticity, where the plastic modulus is a function of the distance between the current and image stress states in the stress space. Based on the concept of fuzzy set theory in mathematics, a membership function whose value ranges from 1 and 0 is introduced to specify the plastic modulus at a given stress state. Hollow cylinder and cubical test results on Hostun sand from the CASE database were selected to assess the fuzzy set plasticity model. The numerical results showed that the fuzzy set model is capable of mimicking and simulating the nonlinear behavior of loose sands under various loading paths. © 2012 American Society of Civil Engineers.

Zhou N.,Central South University | Wang X.,Central South University | Chen Z.,Central South University | Wang Z.,Central South University | Wang Z.,Xiangtan University
Energy | Year: 2013

An experimental system for heat recovery from low-temperature flue gas based on Organic Rankine Cycle (ORC) was constructed. In the system, R123 was selected as working fluid, a scroll expander was used to produce work, and fin tubes heat exchanger was designed as evaporator. Low-temperature flue gas produced by an liquefied petroleum gas (LPG) stove was used as the heat source to simulate industrial flue gas, and its temperature can be controlled in the range of 90-220°C. Relationships between output performance of the system and the evaporating pressure, temperature of the heat source as well as the superheat degree of the working fluid were investigated. The results show that the cycle efficiency, the output power of the expander and its exergetic efficiency increase whilst the heat recovery efficiency decreases with the increment of the evaporating pressure at a certain temperature of the heat source. The influence of the superheat degree of the working fluid on the system output parameters is slight. Under the present experimental conditions, the maximum output power of the expander is 645W, and the cycle efficiency and the heat recovery efficiency are 8.5% and 22%, respectively. © 2013 Elsevier Ltd.

Liu Z.,Central South University | Deng D.,Central South University | De Schutter G.,Ghent University
Construction and Building Materials | Year: 2014

Due to several similarities in deterioration behavior between concrete and other porous materials, sulfate salt weathering is regularly considered to be the degradation mechanism causing the concrete deterioration in evaporation zone of partially buried concrete elements in the sulfate environment. This issue has received increasing attention in recent years. However, according to an extensive literatures review on long term field and laboratory tests in this paper, the experimental results are clearly illogical and contradict with the classic theory of salt weathering of porous materials, such as (1) the sulfate crystals cannot be identified by means of micro-analysis methods in the damaged concrete as direct evidences for sulfate crystallization in concrete; (2) concrete is susceptible to deterioration in a high RH environment; (3) a mere change of cement compositions shows significant influence on concrete damage, however concrete damage is immune to pore structure change; and (4) the damaged concrete part does not contain the highest salt content, and so on. Instead, the experimental results support that the chemical sulfate attack should be still the mechanism causing the concrete deterioration. Therefore, an adequate understanding of deterioration mechanism of concrete in the evaporation zone of partially buried concrete elements is quite urgent. In this paper, several issues aimed at the contradictions deduced from field and laboratory tests are proposed to attempt to seek the truth of sulfate salt weathering of concrete. © 2014 Elsevier Ltd. All rights reserved.

Liu X.,Japan International Center for Materials Nanoarchitectonics | Liu X.,Central South University | Ma R.,Japan International Center for Materials Nanoarchitectonics | Bando Y.,Japan International Center for Materials Nanoarchitectonics | Sasaki T.,Japan International Center for Materials Nanoarchitectonics
Advanced Functional Materials | Year: 2014

A low-cost oil bath synthetic route is presented to produce uniform and highly crystalline layered cobalt hydroxide nanocones (NCs) intercalated with dodecyl sulfate anions (C12H25OSO3-, DS-). A new exfoliating procedure, by gradually unravelling/ unzipping these NCs through heat treatment in formamide-water binary solution, is developed to prepare unilamellar nanosheets. Moreover, the NCs can be readily modified with various inorganic or organic anions via a conventional anion-exchange process at ambient temperature. The exchanged product, for example, NO3--intercalated NCs, can be more easily and rapidly transformed into cobalt oxides (e.g., Co3O4 and CoO) than the original DS--intercalated form while retaining a conical feature. Both the cobalt hydroxide NCs and exfoliated nanosheets are electrochemically redoxable, exhibiting a Faradaic pseudocapacitive behavior. The magnetic measurements further reveal both antiferromagnetic behaviors for transformed Co3O4 and CoO NCs. Their Néel temperature values are lower than those of bulk oxides due to finite size and geometric confinement effect. The peculiar conical feature of NCs with a hollow interior and tunable layer spacing, as well as exfoliated unilamellar nanosheets with all surface area exposed, may show promise for potential applications in electrochemical energy storage and magnetic devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cao H.,Nantong University | Cao H.,Central South University | Chen X.,Central South University | Jassbi A.R.,Shiraz University of Medical Sciences | And 2 more authors.
Biotechnology Advances | Year: 2015

The bioactive flavonoids are considered as the most important phytochemicals in food, which exert a wide range of biological benefits for human being. Microbial biotransformation strategies for production of flavonoids have attracted considerable interest because they allow yielding novel flavonoids, which do not exist in nature. In this review, we summarize the existing knowledge on the production and biotransformation of flavonoids by various microbes. The main reactions during microbial biotransformation are hydroxylation, dehydroxylation, O-methylation, O-demethylation, glycosylation, deglycosylation, dehydrogenation, hydrogenation, C ring cleavage of the benzo-γ-pyrone system, cyclization, and carbonyl reduction. Cunninghamella, Penicillium, and Aspergillus strains are very popular to biotransform flavonoids and they can perform almost all the reactions with excellent yields. Aspergillus niger is one of the most applied microorganisms in the flavonoids' biotransformation; for example, A. niger can transfer flavanone to flavan-4-ol, 2'-hydroxydihydrochalcone, flavone, 3-hydroxyflavone, 6-hydroxyflavanone, and 4'-hydroxyflavanone. The hydroxylation of flavones by microbes usually happens on the ortho position of hydroxyl group on the A ring and C-4' position of the B ring and microbes commonly hydroxylate flavonols at the C-8 position. The microorganisms tend to hydroxylate flavanones at the C-5, 6, and 4' positions; however, for prenylated flavanones, dihydroxylation often takes place on the C4α=C5α double bond on the prenyl group (the side chain of A ring). Isoflavones are usually hydroxylated at the C-3' position of the B ring by microorganisms. The microbes convert flavonoids to their 7-O-glycosides and 3-O-glycosides (when flavonoids have a hydroxyl moiety at the C-3 position). The demethylation of multimethoxyl flavonoids by microbes tends to happen at the C-3' and C-4' positions of the B ring. Multimethoxyl flavanones and isoflavone are demethylated at the C-7 and C-4' positions. The O-methylation of flavonols happens at the C-3' and C-4' and microorganisms O-methylate flavones at the C-6 position and the O-methylation of flavanones, usually took place on the hydroxyl groups of the A ring. The prenyl flavanones were cyclized at the prenyl side chain to form a new five-member ring attached to the A ring. Chalcones were regioselectively cyclized to flavanones. Hydrogenation of flavonoids was only reported on transformation of chalcones to dihydrochalcones. The dehydrogenation of flavanoids to flavonoids was not comprehensively studied. © 2014 Elsevier Inc.

Tan Y.,Central South University | Tan Y.,University of Birmingham | Liu Y.,Central South University | Grover L.,University of Birmingham
Cement and Concrete Research | Year: 2014

Magnesium oxychloride cement (MOC) has been used in civil engineering for more than 100 years, but its application has been limited by its poor water resistance. This property, however, could be exploited in the formulation of a resorbable orthopaedic biomaterial. In this study, H3PO4 was added to control the degradation process of MOC to provide a predictable and clinically appropriate resorption time. The effects of H3PO 4 on the phases, microstructures, mechanical properties, hydration and degradation of MOC have been evaluated. The results revealed that the crystalline phases in MOC before and after adding H3PO4 were the same, but that the needle-like phase 5 (5 Mg(OH)2· MgCl2·8H2O) crystals were formed more extensively in MOC with H3PO4 than that in MOC without H 3PO4. Furthermore, the addition of H3PO 4 was shown to retard the hydration process. H3PO 4 did significantly improve the water resistance of MOC though its addition resulting in a reduction in compressive strength. © 2013 Elsevier Ltd.

Liu X.,Japan International Center for Materials Nanoarchitectonics | Liu X.,Central South University | Ma R.,Japan International Center for Materials Nanoarchitectonics | Bando Y.,Japan International Center for Materials Nanoarchitectonics | Sasaki T.,Japan International Center for Materials Nanoarchitectonics
Angewandte Chemie - International Edition | Year: 2010

Layered cobalt hydroxide nanocones intercalated with dodecyl sulfate (DS) ions (see scheme; OH- blue, Co green dots, DS ions red) could be synthesized by the microwave-assisted rolling of lamellar structures. The cones could be exfoliated into cobalt hydroxide nanosheets and converted into CoOOH and Co3O4 nanocones. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li X.,Central South University | Atkinson M.A.,University of Florida
Pediatric Diabetes | Year: 2015

Increasing evidence, both functional and morphological, supports the concept of increased intestinal permeability as an intrinsic characteristic of type 1 diabetes (T1D) in both humans and animal models of the disease. Often referred to as a 'leaky gut', its mechanistic impact on the pathogenesis of T1D remains unclear. Hypotheses that this defect influences immune responses against antigens (both self and non-self) predominate, yet others argue hyperglycemia and insulitis may contribute to increased gut permeability in T1D. To address these complicated issues, we herein review the many conceptual role(s) for a leaky gut in the pathogenesis of T1D and suggest ways that if true, therapeutic interventions aimed at the gut-pancreas axis may prove promising for future therapeutic interventions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Liu G.,University of Birmingham | Zhang D.,Central South University | Meggs C.,University of Birmingham | Button T.W.,University of Birmingham
Scripta Materialia | Year: 2010

Porous Al2O3-ZrO2 composites with homogeneous and long-range ordered channels were produced by an ice template method. An increase of the initial solids loading from 40 to 70 wt.% caused the final porosity to decrease from 74% to 35%, while the compressive strength increased from 15 to 81 MPa. The sample obtained from the 80 wt.% suspension was not porous, and a critical velocity model is employed to explain this phenomenon. © 2009 Acta Materialia Inc.

Zhao Y.,Central South University | Yang L.,Central South University | Wang X.,Rutgers University | Zhou Z.,Central South University
Diabetes/Metabolism Research and Reviews | Year: 2014

Summary: Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic agents that are widely used in clinical practice to improve glycemic control and protect β-cell function in patients with type 2 diabetes. DPP-4 is also known as lymphocyte cell surface protein CD26 and plays an important role in T-cell immunity. Autoimmune diabetes, a T-cell mediated organ-specific disease, is initiated by the imbalance between pathogenic and regulatory T-lymphocytes. DPP-4 inhibitors can suppress pathogenic effects of Th1 and Th17 cells and up-regulate Th2 cells and regulatory T cells, which play a critical role in ameliorating autoimmune diabetes. This provides a basis for the potential use of DPP-4 inhibitors in the treatment of autoimmune diabetes. Recent studies suggest that DPP-4 inhibitors improve β-cell function and attenuate autoimmunity in type 1 diabetic mouse models. However, there are few clinical studies on the treatment of autoimmune diabetes with DPP-4 inhibitors. Further studies are warranted to confirm the therapeutic effects of DPP-4 inhibitors on autoimmune diabetes in humans. © 2014 John Wiley & Sons, Ltd.

Ma Q.,Harbin Institute of Technology | Liu S.J.,Harbin Institute of Technology | Liu S.J.,Central South University
Electrochimica Acta | Year: 2011

Anatase nanotube arrays were grown by anodization with high crystallinity and a well ordered nanotubular structure. Nanotubes were stable to 800 °C, and this enhanced thermal stability of anatase nanotube arrays (without Ti support) was related to the induced tensile strain/stress inside the nanotube wall. The anatase-to-rutile phase transformation of titania nanotube arrays induces a tensile stress inside the nanotube wall that increases the critical nucleation size of rutile phase, as opposed to a compressive stress usually occurred on the surface of titania thin films or nanoparticles. © 2011 Elsevier Ltd. All rights reserved.

Zhan L.,Central South University | Lin J.,Imperial College London | Dean T.A.,University of Birmingham
International Journal of Machine Tools and Manufacture | Year: 2011

About twenty years ago, the process of Creep Age Forming (CAF) was invented, and since then has been developed for the manufacture of heat treatable aluminium alloy panel components particularly, it has been successfully used for aircraft wing panels. Significant research work has been carried out in recent years and process applications have been expanded. This paper contains a review of recent research and development of this novel forming process. It covers process applications in the aircraft industry and scientific research, including the development of forming tools, experimental studies, materials and process modelling and springback prediction. Some potential future applications and challenges for deeper understanding of this novel process are also discussed. © 2010 Elsevier Ltd. All rights reserved.

Yang M.-G.,Central South University | Li C.-Y.,T.Y. Lin International Engineering Consulting China Co. | Chen Z.-Q.,Hunan University
Engineering Structures | Year: 2013

Non-linear hysteresis is a complicated mechanical characteristic for magneto-rheological (MR) damper. In this paper, a new simple non-linear hysteretic model for MR damper is proposed to represent the hysteretic behavior. First, the force-displacement and force-velocity loops under a range of currents, amplitudes and frequencies are obtained by mechanical behavior test of a RD1097 type MR damper. Then the model's parameters are identified by the non-linear least square method from test data and fitted by the polynomials as functions of the supplied current. Finally, the accuracy and the effectiveness of the model are demonstrated by the RMS errors comparison between the reconstructed hysteretic curves and the experimental ones, and further are verified by seismic response reduction experiment under three excitations including the sinusoidal wave, the Pingsheng Bridge earthquake wave and the El-Centro wave. The results show that the proposed model has higher accuracy than some of existing models with explicit functions and is easier to be identified than those models with non-linear differential equations. Therefore, the proposed model can be effectively applied to simulation analysis in engineering control subjected to frequency-fixed or random excitations. © 2013 Elsevier Ltd.

Zhang L.,Central South University | Zhang L.,Guangzhou First Peoples Hospital | Zhao J.,Central South University
Neuropsychiatric Disease and Treatment | Year: 2014

Accumulating evidence suggests that neuroinflammation affecting microglia plays an important role in the etiology of schizophrenia, and appropriate control of microglial activation may be a promising therapeutic strategy for schizophrenia. Minocycline, a second-generation tetracycline that inhibits microglial activation, has been shown to have a neuroprotective effect in various models of neurodegenerative disease, including anti-inflammatory, antioxidant, and antiapoptotic properties, and an ability to modulate glutamate-induced excitotoxicity. Given that these mechanisms overlap with neuropathologic pathways, minocycline may have a potential role in the adjuvant treatment of schizophrenia, and improve its negative symptoms. Here, we review the relevant studies of minocycline, ranging from preclinical research to human clinical trials. © 2014 Zhang and Zhao.

Xiao J.,Shanghai Normal University | Xiao J.,University of Würzburg | Kai G.,Shanghai Normal University | Yamamoto K.,Okayama Prefectural University | Chen X.,Central South University
Critical Reviews in Food Science and Nutrition | Year: 2013

The dietary polyphenols as α-glucosidases inhibitors have attracted great interest among researchers. The aim of this review is to give an overview of the research reports on the structure-activity relationship of dietary polyphenols inhibiting α-glucosidases. The molecular structures that influence the inhibition are the following: (1) The hydroxylation and galloylation of flavonoids including catechins improve the inhibitory activity. (2) The glycosylation of hyroxyl group and hydrogenation of the C2=C3 double bond on flavonoids weaken the inhibition. (3) However, cyaniding glycosides show higher inhibition against than cyanidin. Proanthocyanidins oligomers exhibit a stronger inhibitory activity than their polymers. (4) The hydroxylation on B ring and the glycosylation of stilbenes reduce the inhibitory activity. (5) Caffeoylquinic acids display strong inhibition against α-glucosidases. However, hydroxycinnamic acid, ferulic acid, and gallic acid hardly inhibited α-glucosidases. (6) The coupled galloyl structures attached to C-3 and C-6 of the 4C1 glucose core of ellagitanin gave basic inhibitory activity. (7) The mono-glycosylation of chalcones slightly lowers the inhibition. However, the diglycosylation of chalcones significantly decreased the activity. © 2013 Copyright Taylor and Francis Group, LLC.

Xiao J.,Shanghai Normal University | Kai G.,Shanghai Normal University | Chen X.,Central South University
Nanotoxicology | Year: 2012

Recently, investigations of biological toxicity of cadmium QDs and their toxic interaction with plasma proteins have attracted great interest. In this work, flavonoids were studied for the affinities for human serum albumin (HSA) in the presence and absence of CdTe G-QDs by fluorescence quenching method. CdTe G-QDs obviously enhanced the binding affinities of kaempferol, genistein and biochanin A by 3.78 to 154.88 times depending on the QDs concentration. However, the affinity of kaempferide for HSA was slightly weakened in the presence of G-QDs. The non-methylated flavonoids were more sensitive to G-QDs than their methylated forms. The affinities of kaempferide and kaempferol for HSA at first were slightly improved and then obviously decreased with increasing G-QDs concentration. For genistein, the affinities for HSA decreased with increasing G-QDs concentration. However, the G-QDs concentration showed no obvious effect on the affinity of biochanin A. The binding affinities of flavonoids for HSA improved with increasing QDs size.

Liu Z.,Central South University | Liu B.,University of Waterloo | Ding J.,Central South University | Liu J.,University of Waterloo
Analytical and Bioanalytical Chemistry | Year: 2014

In the past few years, graphene oxide (GO) has emerged as a unique platform for developing DNA-based biosensors, given the DNA adsorption and fluorescence-quenching properties of GO. Adsorbed DNA probes can be desorbed from the GO surface in the presence of target analytes, producing a fluorescence signal. In addition to this initial design, many other strategies have been reported, including the use of aptamers, molecular beacons, and DNAzymes as probes, label-free detection, utilization of the intrinsic fluorescence of GO, and the application of covalently linked DNA probes. The potential applications of DNA-functionalized GO range from environmental monitoring and cell imaging to biomedical diagnosis. In this review, we first summarize the fundamental surface interactions between DNA and GO and the related fluorescencequenching mechanism. Following that, the various sensor design strategies are critically compared. Problems that must be overcome before this technology can reach its full potential are described, and a few future directions are also discussed. © Springer-Verlag 2014.

Zhou W.,Central South University | Jimmy Huang P.-J.,University of Waterloo | Ding J.,Central South University | Liu J.,Central South University | Liu J.,University of Waterloo
Analyst | Year: 2014

Aptamers are single-stranded nucleic acids that selectively bind to target molecules. Most aptamers are obtained through a combinatorial biology technique called SELEX. Since aptamers can be isolated to bind to almost any molecule of choice, can be readily modified at arbitrary positions and they possess predictable secondary structures, this platform technology shows great promise in biosensor development. Over the past two decades, more than one thousand papers have been published on aptamer-based biosensors. Given this progress, the application of aptamer technology in biomedical diagnosis is still in a quite preliminary stage. Most previous work involves only a few model aptamers to demonstrate the sensing concept with limited biomedical impact. This Critical Review aims to summarize progress that might enable practical applications of aptamers for biological samples. First, general sensing strategies based on the unique properties of aptamers are summarized. Each strategy can be coupled to various signaling methods. Among these, a few detection methods including fluorescence lifetime, flow cytometry, upconverting nanoparticles, nanoflare technology, magnetic resonance imaging, electronic aptamer-based sensors, and lateral flow devices have been discussed in more detail since they are more likely to work in a complex sample matrix. The current limitations of this field include the lack of high quality aptamers for clinically important targets. In addition, the aptamer technology has to be extensively tested in a clinical sample matrix to establish reliability and accuracy. Future directions are also speculated to overcome these challenges. © the Partner Organisations 2014.

Li M.,Central South University | Wu X.,Central South University | Wang J.,Central South University | Pan Y.,Central South University | Pan Y.,Georgia State University
BMC Bioinformatics | Year: 2012

Background: Identification of protein complexes and functional modules from protein-protein interaction (PPI) networks is crucial to understanding the principles of cellular organization and predicting protein functions. In the past few years, many computational methods have been proposed. However, most of them considered the PPI networks as static graphs and overlooked the dynamics inherent within these networks. Moreover, few of them can distinguish between protein complexes and functional modules.Results: In this paper, a new framework is proposed to distinguish between protein complexes and functional modules by integrating gene expression data into protein-protein interaction (PPI) data. A series of time-sequenced subnetworks (TSNs) is constructed according to the time that the interactions were activated. The algorithm TSN-PCD was then developed to identify protein complexes from these TSNs. As protein complexes are significantly related to functional modules, a new algorithm DFM-CIN is proposed to discover functional modules based on the identified complexes. The experimental results show that the combination of temporal gene expression data with PPI data contributes to identifying protein complexes more precisely. A quantitative comparison based on f-measure reveals that our algorithm TSN-PCD outperforms the other previous protein complex discovery algorithms. Furthermore, we evaluate the identified functional modules by using " Biological Process" annotated in GO (Gene Ontology). The validation shows that the identified functional modules are statistically significant in terms of " Biological Process" . More importantly, the relationship between protein complexes and functional modules are studied.Conclusions: The proposed framework based on the integration of PPI data and gene expression data makes it possible to identify protein complexes and functional modules more effectively. Moveover, the proposed new framework and algorithms can distinguish between protein complexes and functional modules. Our findings suggest that functional modules are closely related to protein complexes and a functional module may consist of one or multiple protein complexes. The program is available at © 2012 Li et al.; licensee BioMed Central Ltd.

Xie Y.,Central South University | Xiao J.,Shanghai Normal University | Kai G.,Shanghai Normal University | Chen X.,Central South University
Integrative Biology | Year: 2012

Diabetes is characterized by an elevated level of glucose in the blood. This glucose can form covalent adducts with plasma proteins through a non-enzymatic process known as glycation. It has been suggested that the increasing glycation can influence the ability of plasma proteins to bind to small molecules. Herein, the difference between healthy human plasma proteins (HPP) and type II diabetes plasma proteins (TPP) in binding small molecules was investigated. TPP showed about 1-10 times lower affinities for polyphenols than HPP. The values of lgKa(HPP) are positive proportional to the values of lgKa(TPP) with excellent linear relationship. The glycation of HPP decreased the affinities for HPP by about 1.17 to 16.6 times. The difference between HPP-polyphenol interaction and TPP-polyphenol interaction was bigger for the more lipophilic polyphenols. The affinities for TPP or HPP slightly decreased with increasing hydrogen bond donor numbers of polyphenols and hardly changed with hydrogen bond acceptor numbers. © 2012 The Royal Society of Chemistry.

Liu S.,Hunan University of Technology | Huang C.,Central South University
Buildings | Year: 2016

The unique architectural style of traditional "Yinzi" dwellings inWestern Hunan, China, needs to be protected and their natural ventilation of patio space should also be promoted. Therefore, this study aimed at finding out the natural ventilation values and limitations of "Yinzi" dwellings as well as designing an optimum ventilation strategy for such dwellings. In this work, the thermal environment of a typical "Yinzi" dwelling was tested. The two patios and living room space of "Yinzi" dwellings was selected for a quantitative analysis, and CFD software was adopted to simulate the stack effect of different patio proportions under the same static wind environment conditions. In addition, an orthogonal experiment is combined with CFD simulation to explore the best proportion and position of patio of "Yinzi" dwellings. A final optimum ventilation strategy is provided for the "Yinzi" dwellings, which can significantly promote the natural stack effect of "Yinzi" dwellings in summer. © 2016 by the authors.

Xiao J.,Shanghai Normal University | Ni X.,Fudan University | Kai G.,Shanghai Normal University | Chen X.,Central South University
Critical Reviews in Food Science and Nutrition | Year: 2013

The inhibitory effects of dietary polyphenols against α-amylase have attracted great interest among researchers. The aim of this review is to give an overview of the research reports on the structure-activity relationship of polyphenols inhibiting α-amylase. The molecular structures that influence the inhibition are the following: (1) The hydroxylation of flavonoids improved the inhibitory effect on α-amylase; (2) Presence of an unsaturated 2,3-bond in conjugation with a 4-carbonyl group has been associated with stronger inhibition; (3) The glycosylation of flavonoids decreased the inhibitory effect on α-amylase depending on the conjugation site and the class of sugar moiety; (4) The methylation and methoxylation of flavonoids obviously weakened the inhibitory effect; (5) The galloylated catechins have higher inhibition than nongalloylated catechins; the catechol-type catechins were stronger than the pyrogallol-type catechins; the inhibition activities of the catechins with 2,3-trans structure were higher than those of the catechins with 2,3-cis structure; (6) Cyanidin-3-glucoside showed higher inhibition against than cyanidin and cyanidin-3-galactoside and cyanidin-3,5-diglucoside had no inhibitory activity; (7) Ellagitannins with β-galloyl groups at glucose C-1 positions have higher inhibitory effect than the α-galloyl and nongalloyl compounds and the molecular weight of ellagitannins is not an important element. © 2013 Copyright Taylor and Francis Group, LLC.

Zeng H.-B.,Central South University | Zeng H.-B.,Hunan University of Technology | He Y.,Central South University | Wu M.,Central South University | Zhang C.-F.,Hunan University of Technology
IEEE Transactions on Neural Networks | Year: 2011

This paper is concerned with the problem of stability of neural networks with time-varying delays. A novel LyapunovKrasovskii functional decomposing the delays in all integral terms is proposed. By exploiting all possible information and considering independent upper bounds of the delay derivative in various delay intervals, some new generalized delay-dependent stability criteria are established, which are different from the existing ones and improve upon previous results. Numerical examples are finally given to demonstrate the effectiveness and the merits of the proposed method. © 2011 IEEE.

Zeng H.-B.,Central South University | He Y.,Central South University | Wu M.,Central South University | Xiao S.-P.,Hunan University of Technology
International Journal of Robust and Nonlinear Control | Year: 2011

This paper investigates the problem of absolute stability and stabilization for networked control systems (NCSs) with the controlled plant being Lurie systems (Lurie NCSs), in which the network-induced delays are assumed to be time-varying and bounded. By considering the relationship between the network-induced delay and its upper bound, an improved stability criterion for networked control system is proposed. Furthermore, the resulting condition is extended to design a state feedback controller by employing an improved cone complementary linearization (ICCL) algorithm. A numerical example is worked out to illustrate the effectiveness and the benefits of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.

Ko K.S.,Ewha Womans University | Peng J.,Central South University | Yang H.,University of Southern California
Current Opinion in Gastroenterology | Year: 2013

PURPOSE OF REVIEW: Even though recent accumulated data can help to understand fundamental molecular mechanisms of progression of cholangiocarcinoma (CCA), its incidence and mortality still keep increasing worldwide with poor prognosis. As appropriate animal disease models are critical to fill the gap between the findings from in vitro and the applications to human diseases, lack of effective and patient-like CCA animal models may contribute to limits of controlling progression of CCA. This review is focusing to provide the information about recently developed CCA animal models. RECENT FINDINGS: Recent advancements in cell and molecular biology make it possible to mimic the pathogenicity of human CCA using various animal models. In this review, several up-to-date techniques and the examples to induce CCA in animal models (xenograft and orthotopic models, carcinogen-induced CCA model, genetically engineered mouse model for CCA) with resemblance of human CCA are discussed. SUMMARY: Not only establishing animal models relevant to CCA is beneficial for its early diagnosis and therapy but also well suited experimental CCA models will guide the development of applicable treatment strategy for the hard-to-cure CCA. © 2013 Wolters Kluwer Health | Lippincott Williams &Wilkins.

Li X.-F.,Central South University | Yu Z.-W.,Central South University | Zhang H.,Zhejiang University of Technology
Journal of Constructional Steel Research | Year: 2011

Free vibration of shear beams is studied when rotational motion is taken into account, while classical shear beams do not consider rotational motion. From a single governing equation of Timoshenko beams, we analytically derive Rayleigh beams and shear beams as two limiting cases of the ratio of reduced shear stiffness to bending stiffness being sufficiently large and small, respectively. Emphasis is placed on the analysis of free vibration of nonclassical shear beams without damping effect. Under the condition of general end restraints, a characteristic equation for nonclassical shear beams with finite rotational inertia is derived in explicit form. A condition that the nonclassical shear beams reduce to the classical ones is found, and classical shear beams may be understood as nonclassical ones with infinite large rotational inertia. Nonclassical natural frequencies and mode shapes are calculated for a standing shear beam on an elastic foundation. Previous results of pinned-free, and free-free shear beams can be taken as special cases of the present analysis. The effects of finite rotational inertia, material properties, geometrical conditions and end restraints on the natural frequencies of shear beams are discussed. © 2011 Elsevier Ltd. All rights reserved.

Mannoor K.,University of Maryland, Baltimore | Xu Y.,Central South University | Chen C.,University of Maryland, Baltimore
Autoimmunity | Year: 2013

A substantial proportion of circulating antibodies in healthy individuals exhibit self-reactivity. These antibodies, referred to as natural autoantibodies, are thought to arise naturally without actual antigen stimulation as they are present in human cord blood and in mice housed in germfree conditions and fed an antigen-free diet. Natural autoantibodies are mainly of the IgM class, unmutated, and typically polyreactive. They provide critical early protection against pathogens, and play important roles in maintenance of homeostasis and modulation of innate and adaptive immune responses, thereby conferring protection from rampant autoimmune and inflammatory injuries. In this review, we summarize current information regarding the properties of natural autoantibodies and the B cells that produce them, their roles in immunity and autoimmunity, their mechanisms of action, and their therapeutic potential. © Informa UK, Ltd.

Li M.,Central South University | Zheng R.,Central South University | Zhang H.,Central South University | Wang J.,Central South University | And 2 more authors.
Methods | Year: 2014

Identification of essential proteins is very important for understanding the minimal requirements for cellular life and also necessary for a series of practical applications, such as drug design. With the advances in high throughput technologies, a large number of protein-protein interactions are available, which makes it possible to detect proteins' essentialities from the network level. Considering that most species already have a number of known essential proteins, we proposed a new priori knowledge-based scheme to discover new essential proteins from protein interaction networks. Based on the new scheme, two essential protein discovery algorithms, CPPK and CEPPK, were developed. CPPK predicts new essential proteins based on network topology and CEPPK detects new essential proteins by integrating network topology and gene expressions. The performances of CPPK and CEPPK were validated based on the protein interaction network of Saccharomyces cerevisiae. The experimental results showed that the priori knowledge of known essential proteins was effective for improving the predicted precision. The predicted precisions of CPPK and CEPPK clearly exceeded that of the other 10 previously proposed essential protein discovery methods: Degree Centrality (DC), Betweenness Centrality (BC), Closeness Centrality (CC), Subgraph Centrality (SC), Eigenvector Centrality (EC), Information Centrality (IC), Bottle Neck (BN), Density of Maximum Neighborhood Component (DMNC), Local Average Connectivity-based method (LAC), and Network Centrality (NC). Especially, CPPK achieved 40% improvement in precision over BC, CC, SC, EC, and BN, and CEPPK performed even better. CEPPK was also compared to four other methods (EPC, ORFL, PeC, and CoEWC) which were not node centralities and CEPPK was showed to achieve the best results. © 2014 Elsevier Inc.

Wu F.,Georgia Institute of Technology | Wu F.,Central South University | Lee J.T.,Georgia Institute of Technology | Nitta N.,Georgia Institute of Technology | And 4 more authors.
Advanced Materials | Year: 2015

(Graph Presented). Lithium Iodide (LiI) is reported as a promising electrolyte additive for lithium-sulfur batteries. It induces formation of Li-ion-permeable protective coatings on both positive and negative electrodes, which prevent the dissolution of polysulfides on the cathode and reduction of polysulfides on the anode. In addition to enhancing the cell cycle stability, LiI addition also decreases the cell overpotential and voltage hysteresis. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

Wang J.,Central South University | Peng X.,Central South University | Li M.,Central South University | Pan Y.,Central South University | Pan Y.,Georgia State University
Proteomics | Year: 2013

In recent years, researchers have tried to inject dynamic information into static protein interaction networks (PINs). The paper first proposes a three-sigma method to identify active time points of each protein in a cellular cycle, where three-sigma principle is used to compute an active threshold for each gene according to the characteristics of its expression curve. Then a dynamic protein interaction network (DPIN) is constructed, which includes the dynamic changes of protein interactions. To validate the efficiency of DPIN, MCL, CPM, and core attachment algorithms are applied on two different DPINs, the static PIN and the time course PIN (TC-PIN) to detect protein complexes. The performance of each algorithm on DPINs outperforms those on other networks in terms of matching with known complexes, sensitivity, specificity, f-measure, and accuracy. Furthermore, the statistics of three-sigma principle show that 23-45% proteins are active at a time point and most proteins are active in about half of cellular cycle. In addition, we find 94% essential proteins are in the group of proteins that are active at equal or great than 12 timepoints of GSE4987, which indicates the potential existence of feedback mechanisms that can stabilize the expression level of essential proteins and might provide a new insight for predicting essential proteins from dynamic protein networks. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhao Y.,Hunan University of Technology | Chen H.,Central South University | Huang L.,Hunan University of Technology
Computers and Mathematics with Applications | Year: 2012

In this paper, the existence of positive solutions for the nonlinear Caputo fractional functional differential equation in the form D0+qy(t)+r(t)f( yt)=0,∀t∈(0,1),q∈(n-1,n],y( i)(0)=0, 0≤i≤n-3,αy( n-2)(t)-βy( n-1)(t)=η(t), t∈[-τ,0],γy( n-2)(t)+δy( n-1)(t)= ξ(t),t∈[1,1+a] is studied. By constructing a special cone and using Krasnosel'skii's fixed point theorem, various results on the existence of at least one or two positive solutions to the fractional functional differential equation are established. The main results improve and generalize the existing results. © 2011 Elsevier Ltd. All rights reserved.

Xiang S.,Central South University | Brunner H.,Memorial University of Newfoundland | Brunner H.,Hong Kong Baptist University
BIT Numerical Mathematics | Year: 2013

In this paper, we introduce efficient methods for the approximation of solutions to weakly singular Volterra integral equations of the second kind with highly oscillatory Bessel kernels. Based on the asymptotic analysis of the solution, we derive corresponding convergence rates in terms of the frequency for the Filon method, and for piecewise constant and linear collocation methods. We also present asymptotic schemes for large values of the frequency. These schemes possess the property that the numerical solutions become more accurate as the frequency increases. © 2013 Springer Science+Business Media Dordrecht.

Wang J.,Central South University | Li M.,Central South University | Chen J.,Texas A&M University | Pan Y.,Georgia State University
IEEE/ACM Transactions on Computational Biology and Bioinformatics | Year: 2011

As advances in the technologies of predicting protein interactions, huge data sets portrayed as networks have been available. Identification of functional modules from such networks is crucial for understanding principles of cellular organization and functions. However, protein interaction data produced by high-throughput experiments are generally associated with high false positives, which makes it difficult to identify functional modules accurately. In this paper, we propose a fast hierarchical clustering algorithm HC-PIN based on the local metric of edge clustering value which can be used both in the unweighted network and in the weighted network. The proposed algorithm HC-PIN is applied to the yeast protein interaction network, and the identified modules are validated by all the three types of Gene Ontology (GO) Terms: Biological Process, Molecular Function, and Cellular Component. The experimental results show that HC-PIN is not only robust to false positives, but also can discover the functional modules with low density. The identified modules are statistically significant in terms of three types of GO annotations. Moreover, HC-PIN can uncover the hierarchical organization of functional modules with the variation of its parameter's value, which is approximatively corresponding to the hierarchical structure of GO annotations. Compared to other previous competing algorithms, our algorithm HC-PIN is faster and more accurate. © 2011 IEEE.

Wang J.,Central South University | Li M.,Central South University | Wang H.,Central South University | Pan Y.,Georgia State University
IEEE/ACM Transactions on Computational Biology and Bioinformatics | Year: 2012

Identification of essential proteins is key to understanding the minimal requirements for cellular life and important for drug design. The rapid increase of available protein-protein interaction (PPI) data has made it possible to detect protein essentiality on network level. A series of centrality measures have been proposed to discover essential proteins based on network topology. However, most of them tended to focus only on the location of single protein, but ignored the relevance between interactions and protein essentiality. In this paper, a new centrality measure for identifying essential proteins based on edge clustering coefficient, named as NC, is proposed. Different from previous centrality measures, NC considers both the centrality of a node and the relationship between it and its neighbors. For each interaction in the network, we calculate its edge clustering coefficient. A node's essentiality is determined by the sum of the edge clustering coefficients of interactions connecting it and its neighbors. The new centrality measure NC takes into account the modular nature of protein essentiality. NC is applied to three different types of yeast protein-protein interaction networks, which are obtained from the DIP database, the MIPS database and the BioGRID database, respectively. The experimental results on the three different networks show that the number of essential proteins discovered by NC universally exceeds that discovered by the six other centrality measures: DC, BC, CC, SC, EC, and IC. Moreover, the essential proteins discovered by NC show significant cluster effect. © 2012 IEEE.

Luo Y.-B.,University of Western Australia | Luo Y.-B.,Central South University | Mastaglia F.L.,University of Western Australia | Mastaglia F.L.,Murdoch University
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2015

Dermatomyositis, polymyositis and immune-mediated necrotising myopathy are major forms of idiopathic inflammatory myopathy. We review here recent developments in understanding the pathology and pathogenesis of these diseases, and characterisation of autoantibody biomarkers. Dermatomyositis is traditionally considered to be due to a complement-mediated microangiopathy but the factors responsible for complement activation remain uncertain. Recent studies have emphasised the importance of the type I interferon pathway in the pathogenesis of the disease and have identified autoantibodies with specificities for different clinical subgroups of patients. Polymyositis is characterised by a cytotoxic T cell response targeting as yet unidentified muscle antigens presented by MHC Class I molecules, and can occur in isolation but is more often part of a multi-systemic overlap syndrome. The immune-mediated necrotising myopathies are heterogeneous and are distinguished from polymyositis by the sparseness of inflammatory infiltrates and recognition of an association with specific autoantibodies such as anti-SRP and anti-HMGCR in many cases. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis. © 2014 Elsevier B.V.

Li Q.,University of Maryland, Baltimore | Li Q.,Central South University | Shu Y.,University of Maryland, Baltimore
Pharmaceutical Research | Year: 2014

Purpose: Previous research has led to the recognition of a cGMP signaling pathway governing drug transport. This study is to investigate whether inhibitors of phosphodiesterase type 5 (PDE5), which increase intracellular cGMP levels, modulate the cytotoxicity and uptake of anti-cancer drugs in cancer cells. Methods: The experiments were conducted with and without PDE5 inhibitors: dipyridamole, vardenafil, and/or sildenafil. The cytotoxicity of doxorubicin, cisplatin and oxaliplatin was determined in multiple cancer cell lines derived from different tissues. The cellular uptake of structurally diverse compounds was further examined in lung cancer cells with and without various endocytotic inhibitors. The tumor accumulation and the anti-tumor effect of trastuzumab were examined in a lung cancer xenograft mouse model. Results: Dipyridamole could modulate the cytotoxicity of doxorubicin, cisplatin, and oxaliplatin in cancer cells. Particularly, PDE5 inhibitors increased cellular uptake of structurally diverse compounds into lung cancer cells both in vitro and in vivo. The effect of vardenafil on drug uptake could be blocked by endocytotic inhibitors. The growth of lung cancer xenograft in nude mice was significantly suppressed by addition of vardenafil to trastuzumab treatment. Conclusion: PDE5 inhibitors may increase the efficacy of anti-cancer drugs by increasing endocytosis-mediated cellular drug uptake, and thus serve as adjuvant therapy for certain cancers such as lung cancer. © 2013 Springer Science+Business Media New York.

Liu S.,Central South University | Tao Y.,Central South University | Tao Y.,Key Laboratory of Carcinogenesis and Cancer Invasion | Tao Y.,Key Laboratory of Carcinogenesis
Biological Reviews | Year: 2013

The dynamic interplay between chromatin modification (e.g. DNA methylation) and RNA polymerase II (Pol II) plays a critical role in gene transcription during stem cell development, establishment, and maintenance and in the cellular response to extracellular stimuli such as those that cause DNA damage. Pol II is recruited to the promoter-proximal regions of numerous inactive genes at high conentrations in a process called Pol II stalling. This is a key process prior to gene activation and it involves many interacting factors. Chromatin modification including nucleosome position is dependent on chromatin structure. Stalled genes create a particular structural conformation of chromatin, which acts as a target for chromatin modification. In this way, Pol II stalling may be regarded as a type of signal for chromatin modification in these regions during the dynamic transition between stalled and activated genes. © 2012 Cambridge Philosophical Society.

Xie H.,Central South University | Xie H.,Southern Medical University | Xie H.,Johns Hopkins Hospital | Xie H.,Merck And Co. | Xie H.,Johns Hopkins University
Nature medicine | Year: 2014

Osteogenesis during bone modeling and remodeling is coupled with angiogenesis. A recent study showed that a specific vessel subtype, strongly positive for CD31 and endomucin (CD31(hi)Emcn(hi)), couples angiogenesis and osteogenesis. Here, we found that platelet-derived growth factor-BB (PDGF-BB) secreted by preosteoclasts induces CD31(hi)Emcn(hi) vessel formation during bone modeling and remodeling. Mice with depletion of PDGF-BB in the tartrate-resistant acid phosphatase-positive cell lineage show significantly lower trabecular and cortical bone mass, serum and bone marrow PDGF-BB concentrations, and fewer CD31(hi)Emcn(hi) vessels compared to wild-type mice. In the ovariectomy (OVX)-induced osteoporotic mouse model, serum and bone marrow levels of PDGF-BB and numbers of CD31(hi)Emcn(hi) vessels are significantly lower compared to sham-operated controls. Treatment with exogenous PDGF-BB or inhibition of cathepsin K to increase the number of preosteoclasts, and thus the endogenous levels of PDGF-BB, increases CD31(hi)Emcn(hi) vessel number and stimulates bone formation in OVX mice. Thus, pharmacotherapies that increase PDGF-BB secretion from preosteoclasts offer a new therapeutic target for treating osteoporosis by promoting angiogenesis and thus bone formation.

Qu F.,Central South University | Qu F.,Qufu Normal University | Zhang Y.,Central South University | Rasooly A.,Office of Science and Engineering | Yang M.,Central South University
Analytical Chemistry | Year: 2014

To increase the loading of glucose oxidase (GOx) and simplify glucose biosensor fabrication, hydrogel prepared from ferrocene (Fc) modified amino acid phenylalanine (Phe, F) was utilized for the incorporation of GOx. The synthesized hydrogel displays good biocompatibility and contains a significant number of Fc moieties, which can be considered as an ideal matrix to immobilize enzymes for the preparation of mediator-based biosensors. The hydrogel was studied by scanning electron microscopy, which indicated that it was composed of nanofibers with a diameter of around 50-100 nm and length extended to 1 mm. With the addition of GOx into the hydrogel and by directly dropping the resulting biocomposite onto the electrode surface, a glucose biosensor, that displays good performance due to improved enzyme loading and efficient electron transfer, can be simply constructed. The favorable network structure and good biocompatibility of the hydrogel could effectively avoid enzyme leakage and maintain the bioactivity of the enzymes, which resulted in good stability of the biosensor. The biosensor was utilized for the detection of glucose in blood samples with results comparable to those obtained from the hospital. The hydrogel as a functional component of an amperometric biosensor has implications for future development of biosensors and for clinical applications. © 2014 American Chemical Society.

Zhang H.,Central South University | Ma Z.,Samsung
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2014

The latest High Efficiency Video Coding (HEVC) standard only requires 50% bit-rate of the H.264/AVC at the same perceptual quality, but with a significant encoder complexity increase. Hence, it is necessary and inevitable to develop fast HEVC encoding algorithms for its potential market adoption. In this paper, we propose a fast intra mode decision for the HEVC encoder. The overall fast intra mode decision algorithm consists of both micro- and macro-level schemes. At the micro-level, we propose the Hadamard cost-based progressive rough mode search (pRMS) to selectively check the potential modes instead of traversing all candidates (i.e., up to 35 in HEVC). Fewer effective candidates will be chosen by the pRMS for the subsequent rate-distortion optimized quantization (RDOQ) to derive the rate-distortion (R-D) optimal mode. An early RDOQ skip method is also introduced to further the complexity reduction. At the macro-level, we introduce the early coding unit (CU) split termination if the estimated R-D cost [through aggregated R-D costs of (partial) sub-CUs] is already larger than the R-D cost of the current CU. On average, the proposed fast intra mode decision provides about 2.5×speedup (without any platform or source code level optimization) with just a 1.0% Bjontegaard delta rate (BD-rate) increase using the HEVC common test condition. Moreover, our proposed solution also demonstrates the state-of-the-art performance in comparison with other works. © 2013 IEEE.

Zhang C.,Central South University | Zhang C.,Henan Polytechnic University | Si S.,Central South University | Yang Z.,Henan Polytechnic University
Biosensors and Bioelectronics | Year: 2015

Combining the surface modification and molecular imprinting technique, a novel photoelectrochemical sensing platform with excellent photochemical catalysis and molecular recognition capabilities was established for the detection of uric acid based on the magnetic immobilization of Fe3O4@C nanoparticles onto magnetic glassy carbon electrode (MGCE) and modification of molecularly imprinted TiO2 film on Fe3O4@C. The developed biosensor was highly sensitive to uric acid in solutions, with a linear range from 0.3 to 34μM and a limit of detection of 0.02μM. Furthermore, the biosensor exhibited outstanding selectivity while used in coexisting systems containing various interferents with high concentration. The practical application of the biosensor was also realized for the selective detection of uric acid in spiked samples. The study made a successful attempt in the development of highly selective and sensitive photoelectrochemical biosensor for urine monitoring. © 2014 Elsevier B.V.

Yang Z.,Henan Polytechnic University | Zhang C.,Henan Polytechnic University | Zhang C.,Central South University
Sensors and Actuators, B: Chemical | Year: 2013

Single-enzyme nanoparticles (SENs) with excellent activity and stability were successfully fabricated via the surface modification and in situ aqueous polymerization of separate urease molecule. A novel piezoelectric biosensor was developed for urea determination based on SENs immobilization onto nanoporous alumina membranes prepared by electrical anodization. The process of SENs immobilization was optimized and the performance of the developed urea biosensor was evaluated. The high selectivity, shorter response time (12 s), wider linear range (0.08 μM-1 mM) and lower limit of detection (LOD, 0.05 μM) were observed for the present biosensor. Moreover, a stability study showed a very high stability over time for the frequency response of the biosensor with separated porous alumina/SENs electrode, testifying for the protective nature of the nanoporous alumina membranes and the interest of SENs. The clinical analysis of the urea biosensor confirmed the feasibility of urea determination in urine sample. © 2013 Elsevier B.V.

Yu G.,Shandong Institute of Business and Technology | Feng L.,Central South University
Match | Year: 2013

The connective eccentricity index of a graph G is defined as ξce(G) = ∑ /v ε V (G) d(ν)/ ε(v), where ε(v) and d(ν) denote the eccentricity and the degree of the vertex ν, respectively. In this paper we derive upper or lower bounds for the connective eccentricity index in terms of some graph invariants such as the radius, independence number, vertex connectivity, minimum degree, maximum degree etc. Moreover, we investigate the maximal and the minimal values of connective eccentricity index among all n-vertex graphs with fixed number of pendent vertices and characterize the extremal graphs. In addition, we study the cactus on n vertices with k cycles having the maximal connective eccentricity index.

Zhang H.,Central South University | Ma Z.,Samsung
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Emerging High Efficiency Video Coding (HEVC) video coding standard promises the significant compression performance improvement compared to the H.264/AVC. However it comes with the tremendous encoding complexity increase. Thus, it is very useful and necessary to develop fast algorithms for HEVC, so as to reduce the encoder complexity. In this paper, we propose a fast intra prediction scheme for HEVC to reduce the prediction mode search for each prediction unit. For all available test sequences provided by the JCT-VC, it demonstrates 38% encoding time reduction for all intra case with BD-RATE increase about 2.9%. Several sub-algorithms are developed and integrated for complexity reduction. First, we applied the Hadamard transform on 2:1 downsampled prediction residual to derive the sum of absolute Hadamard transformed difference (SATD) for rough mode decision, where a progressive search process is then used to reduce effective mode candidates for fully rate-distortion optimized quantization (RDOQ). Finally, an early termination based on SATD cost and mode distances is also included in RDOQ process to further complexity reduction. Extensive simulation results demonstrate that our proposed method is quite efficient for intra mode prediction speed-up. Our proposal is complementary to other separated works on fast coding unit, prediction unit, and transform unit decision. We expect more encoder complexity reduction by combing our solution and other fast algorithms. © 2012 Springer-Verlag.

Cao D.-S.,Central South University | Xu Q.-S.,Central South University | Hu Q.-N.,Wuhan University | Liang Y.-Z.,Central South University
Bioinformatics | Year: 2013

Motivation: Molecular representation for small molecules has been routinely used in QSAR/SAR, virtual screening, database search, ranking, drug ADME/T prediction and other drug discovery processes. To facilitate extensive studies of drug molecules, we developed a freely available, open-source python package called chemoinformatics in python (ChemoPy) for calculating the commonly used structural and physicochemical features. It computes 16 drug feature groups composed of 19 descriptors that include 1135 descriptor values. In addition, it provides seven types of molecular fingerprint systems for drug molecules, including topological fingerprints, electro-topological state (E-state) fingerprints, MACCS keys, FP4 keys, atom pairs fingerprints, topological torsion fingerprints and Morgan/circular fingerprints. By applying a semi-empirical quantum chemistry program MOPAC, ChemoPy can also compute a large number of 3D molecular descriptors conveniently. © 2013 The Author.

Ala-Korpela M.,Central South University | Ala-Korpela M.,University of Oulu | Kangas A.J.,University of Oulu | Inouye M.,Walter and Eliza Hall Institute of Medical Research | Inouye M.,University of Melbourne
Trends in Genetics | Year: 2011

Following the widespread use of genome-wide association studies to elucidate the genetic architectures of complex phenotypes, there has been a push to augment existing observational studies with additional layers of molecular information. The resulting high-dimensional data have led the emergence of research in integrative systems biology. Here, we examine recent progress in characterizing biological networks as well as the corresponding conceptual and analytical challenges. Using examples from metabolomics, we contend that integrative systems biology should prompt a re-examination of conventional phenotypic measures where heterogeneous or correlated phenotypes can be fine-mapped. Although still in its infancy, it is apparent that the large-scale characterization of molecular systems will transform our understanding of phenotype, biology and pathogenesis. © 2011 Elsevier Ltd.

Zhang H.,Central South University | Ma Z.,Samsung
Proceedings - IEEE International Symposium on Circuits and Systems | Year: 2013

The emerging High-Efficiency Video Coding video coding standard has shown the significant coding performance improvement compared to the H.264/AVC with the cost of huge complexity increase. Hence, HEVC fast encoding algorithms are highly demanded for real-time applications. In this paper, we propose several early termination schemes for fast intra prediction in HEVC. More specifically, variation of coding mode costs are used to terminate current coding unit (CU) mode decision as well as TU size selection, where the CU costs are derived at the rough mode decision phase using Hadamard transform. Neighboring modes' costs are also used to skip full rate-distortion optimized quantization (RDOQ). For all available test sequences provided by the JCT-VC, it demonstrates about 32% encoding time reduction for All Intra configuration with BD-RATE increase about 1.1%. Our proposal is complementary to some of other fast intra prediction methods such as fast rough mode decision. We expect more encoder speedup by integrating our method with other published works. © 2013 IEEE.

Baker S.P.,Johns Hopkins University | Hu G.,Central South University | Wilcox H.C.,Johns Hopkins University | Baker T.D.,Johns Hopkins University
American Journal of Preventive Medicine | Year: 2013

Background: Recently, suicide exceeded motor vehicle crashes as the leading cause of injury death in the U.S. However, details of this change in suicide methods and the relationship to individual demographics, such as age and societal influences, have not been reported. Purpose: To determine the characteristics of the changes in suicide rates between 2000 and 2010. Methods: Data came from CDC's Web-Based Injury Statistics Query and Reporting System (WISQARS™). Line charts were plotted to reveal changes in suicide rates by firearm, poisoning, and hanging/suffocation (ICD-10 codes: X72-X74, X60-X69, and X70). The measure of change used is the percentage change in suicide rate between 2000 and 2010. Results: The overall suicide rate increased from 10.4 to 12.1 per 100,000 population between 2000 and 2010, a 16% increase. The majority of the increase was attributable to suicide by hanging/suffocation (52%) and by poisoning (19%). Subgroup analysis showed: (1) suicide by hanging/suffocation increased by 104% among those aged 45-59 years and rose steadily in all age groups except those aged ≥70 years; (2) the largest increase in suicide by poisoning (85%) occurred among those aged 60-69 years; and (3) suicide by firearm decreased by 24% among those aged 15-24 years but increased by 22% among those aged 45-59 years. The case fatality rates for suicide by hanging/suffocation during 2000-2010 ranged from 69% to 84%, close to those for suicide by firearm. Analyses were conducted in 2012. Conclusions: Substantial increases in suicide by hanging/suffocation and poisoning merit attention from policymakers and call for innovations and changes in suicide prevention approaches. © 2013 American Journal of Preventive Medicine.

Kanekura T.,Kagoshima University | Chen X.,Central South University
Journal of Dermatological Science | Year: 2010

CD147/basigin, a transmembrane protein belonging to the immunoglobulin super family, was originally cloned as a carrier of Lewis X carbohydrate antigen. CD147 is strongly related to cancer progression; it is highly expressed by various cancer cells including malignant melanoma (MM) cells and it plays important roles in tumor invasiveness, metastasis, cellular proliferation, and in vascular endothelial growth factor (VEGF) production, tumor cell glycolysis, and multi-drug resistance (MDR). CD147 on cancer cells induces matrix metalloproteinase expression by neighboring fibroblasts, leading to tumor cell invasion. In a nude mouse model of pulmonary metastasis from MM, the metastatic potential of CD147-expressing MM cells injected into the tail vein is abolished by CD147 silencing. CD147 enhances cellular proliferation and VEGF production by MM cells; it promotes tumor cell glycolysis by facilitating lactate transport in combination with monocarboxylate transporters, resulting in tumor progression. CD147 is responsible for the MDR phenotype via P-glycoprotein expression. These findings strongly suggest CD147 as a possible therapeutic target for overcoming metastasis and MDR, major obstacles to the effective treatment of malignant cancers. © 2009 Japanese Society for Investigative Dermatology.

Meng F.,Qingdao Technological University | Tan C.,Central South University | Zhang Q.,Beijing Institute of Technology
Knowledge-Based Systems | Year: 2013

The Shapley function is a very effective tool to measure the importance of elements, which can reflect the interactive characteristics among them. In this study we use the Shapley function to propose an induced generalized interval-valued intuitionistic fuzzy hybrid Shapley averaging (IG-IVIFHSA) operator. This operator does not only globally consider the importance of elements and their ordered positions, but also overall reflect the interaction among them and among their ordered positions. It is worth pointing out that most of the existing hybrid aggregation operators are special cases of our operator. Meantime, some important cases are considered, and some desirable properties are studied. Furthermore, the models for the optimal fuzzy measures on attribute set and ordered set are established, respectively. Moreover, an approach to multi-attribute decision making under interval-valued intuitionistic fuzzy environment is developed. Finally, two numerical examples are given to verify the developed method and demonstrate its practicality and feasibility. © 2013 Elsevier B.V. All rights reserved.

Peng H.,Central South University | Xie H.,University of Texas at Austin | Goodenough J.B.,University of Texas at Austin
Journal of Power Sources | Year: 2012

Substitution of B for Ti in Li1+xTi2-xB x(PO4)3 introduces x mobile Li+ ions per formula unit in the solid-station range 0 < x ≤ 0.2. The B 2O3 is also an aid to sintering dense ceramics with more uniform particle size. With x = 0.2, the room-temperature Li+-ion conductivity is σLi = 2.0 × 10-4 S cm -1 with a motional activation energy of 0.48 eV. For x > 0.2, an intergranular B2O3-rich second phase impedes intergranular Li+-ion transport. © 2011 Elsevier B.V. All rights reserved.

Meng F.,Central South University | Meng F.,Qingdao Technological University | Chen X.,Central South University | Zhang Q.,Beijing Institute of Technology
Information Sciences | Year: 2014

In this paper, a new class of fuzzy sets called linguistic hesitant fuzzy sets (LHFSs) is defined, which can address the qualitative preferences of experts as well as reflect their hesitancy, uncertainty and inconsistency. Based on the defined operational laws of LHFSs and the order relationship, two linguistic hesitant fuzzy hybrid aggregation operators are defined: the generalized linguistic hesitant fuzzy hybrid weighted averaging (GLHFHWA) operator and the generalized linguistic hesitant fuzzy hybrid geometric mean (GLHFHGM) operator. Furthermore, to address the situation in which the elements in a set are interdependent, the generalized linguistic hesitant fuzzy hybrid Shapley weighted averaging (GLHFHSWA) operator and the generalized linguistic hesitant fuzzy hybrid Shapley geometric mean (GLHFHSGM) operator are presented, which are extensions of the GLHFHWA and GLHFHGM operators. Models designed to obtain the optimal fuzzy measures and additive measures on an attribute set and on an ordered set are, respectively, constructed. Then, an approach to linguistic hesitant fuzzy multi-attribute decision analysis is developed. Finally, two numerical examples are provided to demonstrate the practicality and efficiency of the proposed procedure. © 2014 Elsevier Inc. All rights reserved.

Xu Q.,Central South University | Xu Q.,Brown University | Hesthaven J.S.,Brown University
Journal of Computational Physics | Year: 2013

We propose stable multi-domain spectral penalty methods suitable for solving fractional partial differential equations with fractional derivatives of any order. First, a high order discretization is proposed to approximate fractional derivatives of any order on any given grids based on orthogonal polynomials. The approximation order is analyzed and verified through numerical examples. Based on the discrete fractional derivative, we introduce stable multi-domain spectral penalty methods for solving fractional advection and diffusion equations. The equations are discretized in each sub-domain separately and the global schemes are obtained by weakly imposed boundary and interface conditions through a penalty term. Stability of the schemes are analyzed and numerical examples based on both uniform and nonuniform grids are considered to highlight the flexibility and high accuracy of the proposed schemes. © 2013 Elsevier Inc.

Wu Y.,Central South University | Wang J.,University of New South Wales | Hu D.,National University of Defense Technology
IEEE Transactions on Signal Processing | Year: 2014

Integration of inertial navigation system (INS) and global navigation satellite system (GNSS) is usually implemented in engineering applications by way of Kalman-like filtering. This form of INS/GNSS integration is prone to attitude initialization failure, especially when the host vehicle is moving freely. This paper proposes an online constrained-optimization method to simultaneously estimate the attitude and other related parameters including GNSS antenna's lever arm and inertial sensor biases. This new technique benefits from self-initialization in which no prior attitude or sensor measurement noise information is required. Numerical results are reported to validate its effectiveness and prospect in high accurate INS/GNSS applications. © 2014 IEEE.

Wang H.,Hunan University | Li E.,Central South University | Li G.Y.,Hunan University
Computational Mechanics | Year: 2011

This paper presents a crashworthiness design optimization method based on a metamodeling technique. The crashworthiness optimization is a highly nonlinear and large scale problem, which is composed various nonlinearities, such as geometry, material and contact and needs a large number expensive evaluations. In order to obtain a robust approximation efficiently, a probability-based least square support vector regression is suggested to construct metamodels by considering structure risk minimization. Further, to save the computational cost, an intelligent sampling strategy is applied to generate sample points at the stage of design of experiment (DOE). In this paper, a cylinder, a full vehicle frontal collision is involved. The results demonstrate that the proposed metamodel-based optimization is efficient and effective in solving crashworthiness, design optimization problems. © 2010 Springer-Verlag.

Wang H.,Hunan University | Li G.Y.,Hunan University | Li E.,Central South University
Computer Methods in Applied Mechanics and Engineering | Year: 2010

In automotive industry, structural optimization for crashworthiness criteria is of special importance in the early design stage. To reduce the vehicle design cycle, metamodeling techniques have become so widespread... In this study, a time-based metamodeling technique is proposed for the vehicle design. The characteristics of the proposed method are the construction of a time-based objective function and establishment of a metamodel by support vector regression (SVR). Compared with other popular metamodel-based optimization methods, the design space of the proposed method is expanded to time domain. Thus, more information and features can be extracted in the expanded time domain. To validate the performance of the time-based metamodeling technique, cylinder impacting and full vehicle frontal collision are optimized by the proposed method. The results demonstrate that the proposed method has potential capability to solve the crashworthiness vehicle design. © 2010 Elsevier B.V.

Wang H.,Central South University | Liu S.,Central South University | Ren Y.,China National Institute of Clean and Low Carbon Energy | Wang W.,Central South University | Tang A.,Central South University
Energy and Environmental Science | Year: 2012

A novel two-step approach was developed to fabricate well-dispersed Na 1.08V 3O 8 nanosheets, which consist of ultra-thin monolayer sheets with a thickness of ca. 10 nm. The formation mechanism of nanosheets involves the fusion and conversion of nanorods. When used as a cathode material for Li-ion batteries, the nanosheets show superior rate capability, with discharge capacities of ca. 200.0, 131.3, 109.9, 94.2 and 72.5 mA h g -1 at 0.4, 10, 20, 30 and 50 C, respectively. Excellent cycling stability without considerable capacity loss over 200 cycles is observed at 600 and 1000 mA g -1. It is believed that the unique nanosheet morphology as well as its intrinsic structural features greatly facilitate the kinetics of Li-ion diffusion and excellent structure stability, thus resulting in superior electrochemical performance. © 2012 The Royal Society of Chemistry.

Gu J.,Central South University | Song M.,Central South University | Ni S.,Central South University | Guo S.,Southwest University | He Y.,Central South University
Materials and Design | Year: 2013

In this paper, the effects of isothermal annealing on the hardness and elastic modulus of a Cu36Zr48Al8Ag8 bulk metallic glass (BMG) were investigated. It has been shown that the Vickers hardness increases from ~481Hv (as-cast state) to ~518Hv after annealed for 20min. Nanoindentation tests also showed that the hardness and elastic modulus increase from ~6.45GPa and ~113.0GPa (as-cast state) to ~7.27GPa and ~130.9GPa after annealed for 20min, respectively. The results indicated that the free volume of the BMG decreased and nanocrystals nucleated during annealing. The annihilation of the free volume decreased the nucleation ratio/sites of the shear bands, while the nucleation of nanocrystals inhibited the propagation of the shear bands. Both effects are responsible for the enhancement of the hardness and elastic modulus of the BMG. © 2013 Elsevier Ltd.

Yang M.-G.,Central South University | Chen Z.-Q.,Hunan University | Hua X.-G.,Hunan University
Soil Dynamics and Earthquake Engineering | Year: 2011

In this paper, the seismic response reduction performance of magnetorheological (MR) damper is experimentally investigated for a suspension bridge. First, the force-displacement and force-velocity curves under a range of excitation frequencies, amplitudes and currents are obtained by mechanical behavior test of the RD1097 type MR damper. Then a new non-linear hysteretic model is proposed to model the mechanical behavior of the MR damper and the model parameters are identified from test data. An experimental method, as well as a set of testing setups with the MR damper for longitudinal seismic response reduction of a SDOF generalized system representing the fundamental longitudinal mode of suspension bridge, is developed. Finally, the seismic response reduction experiment subject to three kinds of earthquake excitations, including the Pingsheng Bridge earthquake wave, the El-Centro wave and the Taft wave, is carried out, and nine control cases, including uncontrolled, six passive control schemes with different input currents and two semi-active Bang-Bang control schemes, are tested. The results verify that the seismic response reduction experimental method is feasible and the good performance of seismic longitudinal response reduction of the suspension bridge can be achieved by MR damper. It is also shown that the passive control with optimum input current outperforms the semi-active Bang-Bang controls. © 2011 Elsevier Ltd.

Siddiqui C.,University of Central Florida | Abdel-Aty M.,University of Central Florida | Huang H.,Central South University
Accident Analysis and Prevention | Year: 2012

Exploring the significant variables related to specific types of crashes is vitally important in the planning stage of a transportation network. This paper aims to identify and examine important variables associated with total crashes and severe crashes per traffic analysis zone (TAZ) in four counties of the state of Florida by applying nonparametric statistical techniques such as data mining and random forest. The intention of investigating these factors in such aggregate level analysis is to incorporate proactive safety measures in transportation planning. Total and severe crashes per TAZ were modeled to provide predictive decision trees. The variables which carried higher weight of importance for total crashes per TAZ were - total number of intersections per TAZ, airport trip productions, light truck productions, and total roadway segment length with 35 mph posted speed limit. The other significant variables identified for total crashes were total roadway length with 15 mph posted speed limit, total roadway length with 65 mph posted speed limit, and non-home based work productions. For severe crashes, total number of intersections per TAZ, light truck productions, total roadway length with 35 mph posted speed limit, and total roadway length with 65 mph posted speed limit were among the significant variables. These variables were further verified and supported by the random forest results. © 2011 Elsevier Ltd. All rights reserved.

Lin H.,Central South University | Sun S.,China University of Mining and Technology
Disaster Advances | Year: 2012

Layered rock mass slopes widely existed in the practice of geotechnical engineering. Therefore, the study of their deformation and mechanical properties is essential for the safe design of slopes. This study uses FLAC3D numerical calculation software to simulate interactions between layered rock mass slope and pile. In the process of numerical simulation, a three-spring pile unit is employed to simulate piles placed in six positions of the slope. By changing the length of the pile, this article performs a research on the reinforcement effect of pile from different influencing factors, such as overall displacement of slope, monitoring point displacement and shear stress of slope rock mass. The analysis reveals that, when pile positions are set at the middle and lower parts to ensure that piles pass through the most dangerous slip surface, the best deformation effect of rock mass results. Piles at the slope toe helps change the stress condition of the corresponding rock mass and decrease the stress concentration phenomenon. As the pile length increases, the displacement saltation in the slope occurs on a gradually decreasing basis and presents a well-distributed changing trend. A critical pile length exists and controlling displacement by proceeding with increasing pile length renders no obvious effect when the length goes beyond critical pile length.

Su J.,Central South University | Wang Q.,Hunan Provincial Peoples Hospital | Liu Y.,Central South University | Zhong M.,Central South University
Molecular and Cellular Biochemistry | Year: 2014

The poor prognosis of hepatocellular carcinoma (HCC) is mainly due to the development of invasion and metastasis. Recent data strongly suggests the important role of miRNAs in cancer progression, including invasion and metastasis. Here, we found miR-217 expression was much lower in highly invasive MHCC-97H HCC cells and metastatic HCC tissues. Restored miR-217 expression with miR-217 mimics inhibited invasion of MHCC-97H cells. Inversely, miR-217 inhibition enhanced the invasive ability of Huh7 and MHCC-97L cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated E2F3 was a novel direct target of miR-217. Moreover, E2F3 protein level was positively associated with HCC metastasis and functional analysis confirmed the positive role of E2F3 in HCC cell invasion. Our findings suggest miR-217 function as a potential tumor suppressor in HCC progression and miR-217-E2F3 axis may be a novel candidate for developing rational therapeutic strategies. © Springer Science+Business Media 2014.

Li W.,Shenzhen Childrens Hospital | Jiang D.,Central South University
Journal of Pediatric Ophthalmology and Strabismus | Year: 2012

Purpose: To explore the effect of resveratrol on B-cell leukemia/lymphoma-2 (Bcl-2) and vascular endothelial growth factor (VEGF) expression in rats with oxygen-induced retinopathy of prematurity (ROP). Methods: Seven-day-old Sprague-Dawley rats (N = 60) were randomly assigned to five groups. Group A received normal partial oxygen pressure and groups B, C, D, and E received 75% ± 2% oxygen for 5 days to induce ROP. The rats in groups C, D, and E were intragastrically treated with resveratrol (10, 30, and 60 mg/kg/d, respectively) once daily for 5 days. Rats were killed at 17 days of age and the retina was collected. Results: Western blot analysis revealed increased Bcl-2 protein expression in group B versus group A. Levels of Bcl-2 decreased with the increase of resveratrol concentration in groups C, D, and E. The optical density of Bcl-2 protein expression in group B was four times higher than that in group A (P < .01). When compared with group B, expression of Bcl-2 and VEGF in groups C, D, and E decreased in a dose-dependent manner. Significant differences in expression of Bcl-2 and VEGF were also noted among the three treatment groups with resveratrol (P < .01). After treatment with resveratrol at 10, 30, and 60 mg/kg/d, the inhibition rate of Bcl-2 expression was 11.1%, 38.1%, and 69.8% and that of VEGF expression was 3.4%, 23.0%, and 43.7%, respectively. Conclusion: Resveratrol can significantly inhibit expression of Bcl-2 and VEGF in the retina of neonatal rats with oxygen-induced ROP. It may provide a protective effect on retinal neovascular diseases, including ROP. © SLACK Incorporated.

Yang D.-R.,Hunan University | Zhu H.-Z.,Hunan University | Zhu H.-Z.,Central South University
World Journal of Gastroenterology | Year: 2015

Hepatitis C virus (HCV) is a major human pathogen of chronic hepatitis and related liver diseases. Innate immunity is the first line of defense against invading foreign pathogens, and its activation is dependent on the recognition of these pathogens by several key sensors. The interferon (IFN) system plays an essential role in the restriction of HCV infection via the induction of hundreds of IFN-stimulated genes (ISGs) that inhibit viral replication and spread. However, numerous factors that trigger immune dysregulation, including viral factors and host genetic factors, can help HCV to escape host immune response, facilitating viral persistence. In this review, we aim to summarize recent advances in understanding the innate immune response to HCV infection and the mechanisms of ISGs to suppress viral survival, as well as the immune evasion strategies for chronic HCV infection. © 2015 Baishideng Publishing Group Inc. All rights reserved.

Yang T.,Hunan University | Li Q.,Hunan University | Zhou B.,Central South University
Information Sciences | Year: 2013

In terms of attribute reduction of covering based rough sets, the discernibility matrix is used as a conventional method to compute all attribute reducts. However, it is inapplicable to attribute reduction in certain circumstances. In this article, a new method, referred to as the related family, is introduced to compute all attribute reducts and relative attribute reducts for covering rough sets. Its core idea is to remove superfluous attributes while keeping the approximation space of covering information system unchanged. The related family method is more powerful than the discernibility matrix method, since the former can handle complicated cases that could not be handled by the latter. In addition, a simplified version of the related family and its corresponding heuristic algorithm are also presented. © 2012 Elsevier Inc. All rights reserved.

Cheng Y.-S.,Central South University | Cheng Y.-S.,Chinese Academy of science
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

The geological investigation of the Dachang ore field was carried out in detail, and the geological characteristics of the deposits, consisting of the Tongkeng and Dafulou deposits, were observed and researched systematically. It suggests that the mineralization types of Changpo ore are composed of cracking vein, thin vein, bedded vein and thin vein-net vein disseminated types. The cracking vein ore is usually lens-shaped in the vertical direction. The thin vein ore is always characterized by a stable trend and tendency. The bedded ore always occurs along the strata in the way of filling and metasomatism in the fracture system. In terms of Bali-longtoushan ore, it is characterized by complicated mineral components and a variety of minerals. More generally, ore textures consist of the anhedral-subhedral shapes and thin particle, and secondary with the interstitial texture, solid solution separation texture, dissolution texture, corona texture, and crushing texture, yet ore structures include the massive, veinlet, disseminated, banded, miarolitic, biological residual and brecciated structure. In addition, the sulfur isotopes of the metal sulfide were analyzed. The results show that the d34S values of Tongkeng ore range from -0.30% to 1.38% with more dispersed characteristics, yet in terms of Dafulou ore, the d34S values are from -0.15% to 0.22% which are characterized by more focused. This indicates that the sulfur isotope composition has large difference between the different deposits. The sulfur isotope values of the Dafulou ore are concentrated relatively, yet are dispersed for the Tongkeng ore. Likewise, there are also divergences of sulfur isotopes for the different minerals. The sulfur isotope values of pyrrhotine are dispersed, yet are homogeneous for pyrite. In short, the divergence of the sulfur isotope is reflected in both the different deposits and minerals, all of these may account for the difference of sulfur sources. © 2014 The Nonferrous Metals Society of China.

Zhao Z.,Hunan University | Fan H.,Hunan University | Zhou G.,Central South University | Bai H.,Hunan University | And 4 more authors.
Journal of the American Chemical Society | Year: 2014

A novel dual-activatable fluorescence/MRI bimodal platform is designed for tumor cell imaging by using a redoxable manganese dioxide (MnO2) nanosheet-aptamer nanoprobe. The redoxable MnO2 nanosheet acts as a DNA nanocarrier, fluorescence quencher, and intracellular glutathione (GSH)-activated MRI contrast agent. In the absence of target cells, neither fluorescence signaling nor MRI contrast of the nanoprobe is activated. In the presence of target cells, the binding of aptamers to their targets weakens the adsorption of aptamers on the MnO2 nanosheets, causing partial fluorescence recovery, illuminating the target cells, and also facilitating the endocytosis of nanoprobes into target cells. After endocytosis, the reduction of MnO2 nanosheets by GSH further activates the fluorescence signals and generates large amounts of Mn2+ ions suitable for MRI. This platform should facilitate the development of various dual-activatable fluorescence/MRI bimodalities for use in cells or in vivo. © 2014 American Chemical Society.

Li G.,Central South University | De Clercq E.,Rega Institute for Medical Research
Microbiology and Molecular Biology Reviews | Year: 2016

The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Lin Y.C.,Central South University | Chen X.-M.,Central South University | Chen G.,Tianjin University
Journal of Alloys and Compounds | Year: 2011

Uniaxial ratcheting and low-cycle fatigue failure behaviors of hot-rolled AZ91D magnesium alloy were studied by uniaxial cyclic stress-controlling tension deformation experiments. The effects of stress amplitude, mean stress and stress rate on the uniaxial ratcheting response and fatigue life of the hot-rolled AZ91D magnesium alloy were analyzed. Results show that (1) the ratcheting strain and ratcheting strain rate of the hot-rolled AZ91D magnesium alloy both increase with the increase of stress amplitude or mean stress; (2) increasing stress rate will decrease the ratcheting strain and ratcheting strain rate of the hot-rolled AZ91D magnesium alloy; (3) the increase of stress amplitude and mean stress can both reduce the fatigue life of the hot-rolled AZ91D magnesium alloy, while the fatigue life will be prolonged with the increase of stress rate. © 2011 Elsevier B.V. All rights reserved.

Ren W.-X.,Central South University | Chen H.-B.,National Engineering Laboratory for High Speed Railway Construction
Engineering Structures | Year: 2010

Fast-running response surface models that approximate multivariate input/output relationships of time-consuming physical-based computer models enable effective finite element (FE) model updating analyses. In this paper, a response surface-based FE model updating procedure for civil engineering structures in structural dynamics is presented. The key issues to implement such a model updating are discussed such as sampling with design of experiments, selecting the significant updating parameters and constructing a quadratic polynomial response surface. The objective function is formed by the residuals between analytical and measured natural frequencies. Single-objective optimization with equal weights of natural frequency residual of each mode is used for optimization computation. The proposed procedure is illustrated by a simulated simply supported beam and a full-size precast continuous box girder bridge tested under operational vibration conditions. The results have been compared with those obtained from the traditional sensitivity-based FE model updating method. The real application to a full-size bridge has demonstrated that the FE model updating process is efficient and converges fast with the response surface to replace the original FE model. With the response surface at hand, an optimization problem is formulated explicitly. Hence, no FE calculation is required in each optimization iteration. The response surface-based FE model updating can be easily implemented in practice with available commercial FE analysis packages. © 2010 Elsevier Ltd.

Deng C.,Central South University | Chen J.,Hunan University | Nie Z.,Hunan University | Si S.,Central South University
Biosensors and Bioelectronics | Year: 2010

A novel strategy for fabricating the sensitive and stable biosensor was present by layer-by-layer (LBL) self-assembling glucose oxidase (GOD) on multiwall carbon nanotube (CNT)-modified glassy carbon (GC) electrode. GOD was immobilized on the negatively charged CNT surface by alternatively assembling a cationic poly(ethylenimine) (PEI) layer and a GOD layer. And the direct electrochemistry of GOD in the self-assembled {GOD/PEI}n film was investigated. CNT as an excellent nanomaterial greatly improved the direct electron transfer between GOD in {GOD/PEI}n film and the electrode. And the ultrathin {GOD/PEI}n film on the CNT surface provided a favorable microenvironment to keep the bioactivity of GOD. Moreover, PEI used as an out-layer was adsorbed on the top of the {GOD/PEI}n film to form the sandwich-like structure (PEI/{GOD/PEI}n), improving the stability of the enzyme electrode. On basis of these, the developed PEI/{GOD/PEI}n/CNT/GC biosensor has a high sensitivity of 106.57μAmM-1cm-2, and can measure as low as 0.05mM glucose. In addition, the biosensor has excellent operational stability with no decrease in the activity of enzyme over a 1-week period. Therefore, the developed strategy making use of the advantages of CNT and LBL assembly is ideal for the direct electrochemistry of the redox enzymes and the construction of the sensitive and stable enzyme biosensor. © 2010 Elsevier B.V.

Li S.,Central South University | Zhang B.,Xinxiang Medical University | Guo Y.,Central South University | Zhang J.,Central South University
Psychiatry Research | Year: 2015

Patients with depression exhibit high rates of alexithymia, representing a major public health concern. We sought to examine relationships between depression severity and alexithymia as assessed by the Toronto Alexithymia Scale (TAS-20) and the TAS-20 subscales of difficulty identifying feelings (DIF), difficulty describing feelings (DDF), and externally oriented thinking (EOT). Potentially relevant studies were obtained independently by two reviewers. Chi-square statistics based on the Q-test and I2 index assessed statistical heterogeneity between studies. Subgroup analyses were mainly used to explore sources of heterogeneity. Begg[U+05F3]s test and Duval and Tweedie' trim and fill were used to assess potential publication bias. Altogether, 3572 subjects from 20 study groups across 19 studies were included. Medium relationships were observed between depression and TAS-total score (TAS-TS), DIF, and DDF. There was also a weak relationship between EOT and depression. Subgroup analyses showed a stronger correlation between TAS-TS and depression assessed by self-reported tools than that assessed by the Hamilton Rating Scale for Depression. The heterogeneity significantly decreased only in the subgroup analysis by depression tool. We conclude that alexithymia, as assessed by the TAS-20 and its subscales DIF and DDF, is closely related to depression. These relationships were affected by depression measurement tools. © 2015 Elsevier Ireland Ltd.

Wang S.,Central South University | Luna R.,Missouri University of Science and Technology
Journal of Materials in Civil Engineering | Year: 2014

Low-plasticity silt is known to have a potential to liquefy during earthquakes. The compressibility characteristics could change before and after a dynamic event that produces liquefaction. This research investigates the liquefaction resistance and postliquefaction reconsolidation characteristics of Mississippi River Valley (MRV) silt using laboratory cyclic triaxial compression testing. The MRV silt experienced initial liquefaction under cyclic loading, and the results are presented as cyclic stress ratio versus loading cycle curve. After cyclic loading, the liquefied specimens were reconsolidated. Permeability did not change significantly as a result of liquefaction. The reconsolidation curves are more parallel to the compression line than the recompression line in e- log σ ' 3 space, suggesting reconsolidation behaved more like preliquefaction compression. The postliquefaction compression and recompression indexes show less compressibility when compared with preliquefaction conditions. These characteristics of MRV silt suggest that reconsolidation after liquefaction should be a consideration during design of civil infrastructure. © 2014 American Society of Civil Engineers.

Rao Z.H.,Central South University | Liao S.M.,Central South University | Tsai H.L.,Missouri University of Science and Technology
Science and Technology of Welding and Joining | Year: 2011

Hybrid welding, which is the integration of laser beam welding (LBW) and gas metal arc welding (GMAW), may minimise the disadvantages while retaining the advantages for each of the two welding technologies and, hence, has recently received increasing interest in the welding industry. However, the hybrid welding involves very complex transport phenomena which are inherited from each of LBW and GMAW and their interactions. The development of hybrid welding has been based on the trial and error procedure and so far rather limited numerical modelling on hybrid welding is available. This paper presents an up to date literature review on modelling of the hybrid welding including LBW and GMAW. Issues and challenges for a comprehensive hybrid welding model are discussed. With the advances of numerical techniques and computers, a comprehensive hybrid welding model can be developed as a useful tool for determining key process parameters and helping the elimination/reduction of possible weld defects. © 2011 Institute of Materials, Minerals and Mining.

Zhang Y.,Central South University | Zhao M.,Central South University | Sawalha A.H.,University of Michigan | Richardson B.,University of Michigan | And 2 more authors.
Journal of Autoimmunity | Year: 2013

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by production of autoantibodies against a series of nuclear antigens. Although the exact cause of SLE is still unknown, the influence of environment, which is largely reflected by the epigenetic mechanisms, with DNA methylation changes in particular, are generally considered as key players in the pathogenesis of SLE. As an important post-translational modification, DNA methylation mainly suppresses the expression of relevant genes. Accumulating evidence has indicated that abnormal DNA hypomethylation in T cells is an important epigenetic hallmark in SLE. Apart from those classic methylation-sensitive autoimmunity-related genes in lupus, such as CD11a (ITGAL), Perforin (PRF1), CD70 (TNFSF7), CD40 ligand (TNFSF5) and PP2Acα, the genome-wide methylation pattern has also been explored recently, providing us a more and more full-scale picture of the abnormal status of DNA methylation in SLE. On the other hand, certain miRNAs, RFX1, defective ERK pathway signaling, Gadd45α and DNA hydroxymethylation have been proposed as potential mechanisms leading to DNA hypomethylation in lupus. In this review, we summarize current understanding of T cell DNA methylation changes and the consequently altered gene expressions in lupus, and how they contribute to the development of SLE. Possible mechanisms underlying these aberrancies are also discussed based on the reported literature and our own findings. © 2013 Elsevier Ltd.

Liu H.,Central South University | Liu H.,University of Rostock | Tian H.-Q.,Central South University | Pan D.-F.,Central South University | And 2 more authors.
Applied Energy | Year: 2013

Wind speed forecasting is important for the security of wind power integration. Based on the theories of wavelet, wavelet packet, time series analysis and artificial neural networks, three hybrid models [Wavelet Packet-BFGS, Wavelet Packet-ARIMA-BFGS and Wavelet-BFGS] are proposed to predict the wind speed. The presented models are compared with some other classical wind speed forecasting methods including Neuro-Fuzzy, ANFIS (Adaptive Neuro-Fuzzy Inference Systems), Wavelet Packet-RBF (Radial Basis Function) and PM (Persistent Model). The results of three experimental cases show that: (1) the proposed three hybrid models have satisfactory performance in the wind speed predictions, and (2) the Wavelet Packet-ANN model is the best among them. © 2013 Elsevier Ltd.

Zhao Z.,Central South University | Zhao Z.,Key Laboratory for Metallurgy and Material Processing of Rare Metals | Chen X.,Central South University | Hao M.,Central South University
Energy | Year: 2011

A new hydrogen generation material, Al-Ca alloy, is prepared by ball milling method. Results show the prepared Al-Ca alloy can react with to produce hydrogen, but its hydrogen yield is lower. NaCl addition can further greatly improve hydrogen generation of Al-Ca alloys. The amount of NaCl addition and ball milling time depends on the Ca contents of alloys. As the Ca contents of alloy increase, the amount of NaCl addition or ball milling time may be reduced accordingly. Increasing Ca contents, NaCl addition or ball milling time is beneficial to improve the hydrogen generation rate. Al-Ca alloys can react with water to produce hydrogen at the temperature ranging from 10°C to 80°C, and simultaneously a great amount of heat is released. With the increase of air exposure time, the dense Al 2O 3 and CaO layer formed on the surface of alloy particles will reduce the oxidation reaction rate. Chloride ions and sulfate ions can greatly decrease the induction period of hydrogen generation reaction and obviously improve hydrogen generation rate. Ca 2+ ions and Mg 2+ ions can affect the production of hydrogen due to their strong affinity to OH -, especially Mg 2+ ions which greatly decrease the hydrogen yield to 20%. © 2011 Elsevier Ltd.

Liu H.,Central South University | Liu H.,University of Rostock | Tian H.-Q.,Central South University | Li Y.-F.,Central South University | Li Y.-F.,University of Rostock
Applied Energy | Year: 2012

Wind speed prediction is important to protect the security of wind power integration. The performance of hybrid methods is always better than that of single ones in wind speed prediction. Based on Time Series, Artificial Neural Networks (ANN) and Kalman Filter (KF), in the study two hybrid methods are proposed and their performance is compared. In hybrid ARIMA-ANN model, the ARIMA model is utilized to decide the structure of an ANN model. In hybrid ARIMA-Kalman model, the ARIMA model is employed to initialize the Kalman Measurement and the state equations for a Kalman model. Two cases show both of them have good performance, which can be applied to the non-stationary wind speed prediction in wind power systems. © 2012 Elsevier Ltd.

Wang H.,Central South University | Wang W.,Central South University | Ren Y.,University of St. Andrews | Huang K.,Central South University | Liu S.,Central South University
Journal of Power Sources | Year: 2012

Single crystalline Na2V6O16·2. 36H2O nanowires are synthesized by a facile hydrothermal method as a new cathode material for Li-ion battery. The nanowires show a diameter of 60-100 nm and a length of up to 5 μm. Appropriate thermal treatment could effectively improve the cycling performance, although the discharge capacity is sacrificed to some extent. Na2V6O16·0. 86H2O after heat treatment under 300 °C delivers an initial specific discharge capacity of 235.2 mAh g-1 at 30 mA g-1, with a capacity retention of 91.1% after 30 cycles. Long cycling test is demonstrated by the retention of 90.4% and 94.4% at 150 and 300 mA g -1, respectively, after 80 cycles. Good rate capability is also achieved for this material. It is proposed that the improved cycling stability of the electrode after thermal treatment is mainly attributed to the removal of a part of crystal water, accompanied with certain structural arrangement. © 2011 Elsevier B.V. All rights reserved.

Liu H.,Central South University | Liu H.,University of Rostock | Tian H.-Q.,Central South University | Li Y.-F.,Central South University
Energy Conversion and Management | Year: 2014

The technology of wind speed prediction is important to guarantee the safety of wind power utilization. Compared to the single algorithms, the hybrid ones always have better performance in the wind speed predictions. In this paper, three most important decomposing algorithms [Wavelet Decomposition - WD/Wavelet Packet Decomposition - WPD/Empirical Mode Decomposition - EMD] and a latest decomposing algorithm [Fast Ensemble Empirical Mode Decomposition - FEEMD] are all adopted to realize the wind speed high-precision predictions with two representative networks [MLP Neural Network/ANFIS Neural Network]. Based on the hybrid forecasting framework, two new wind speed forecasting methods [FEEMD-MLP and FEEMD-ANFIS] are proposed. Additionally, a series of performance comparison is provided, which includes EMD-MLP, FEEMD-MLP, EDM-ANFIS, FEEMD-ANFIS, WD-MLP, WD-ANFIS, WPD-MLP and WPD-ANFIS. The aim of the study is to investigate the decomposing and forecasting performance of the different hybrid models. Two experimental results show that: (1) Due to the inclusion of the decomposing algorithms, the hybrid ANN algorithms have better performance than their corresponding single ANN algorithms; (2) the proposed new FEEMD-MLP hybrid model has the best performance in the three-step predictions while the WPD-MLP hybrid model has the best performance in the one-step predictions; (3) among the decomposing algorithms, the FEEMD and WPD have better performance than the EMD and WD, respectively; (4) in the forecasting neural networks, the MLP has better performance than the ANFIS; and (5) all of the proposed hybrid algorithms are suitable for the wind speed predictions. © 2014 Elsevier Ltd.

Wang J.,Central South University | Liu Z.,Central South University | Liu Z.,Changsha University | Zhang S.,Central South University | Zhang X.,Texas A&M University
Information Sciences | Year: 2014

False data filtering is an important issue in wireless sensor networks. In this paper, we consider a new type of false data injection attacks called collaborative false data injection, and propose two schemes to defend such attacks. In collaborative false data injection attacks, multiple compromised nodes collaboratively forge a fake report and inject the report into the network. This type of attacks is hard to defend with existing approaches, because they only verify a fixed number of message authentication codes (MACs) carried in the data report but the adversary can easily obtain enough compromised nodes from different geographical areas of the network to break their security. Our novel solution is to bind the keys of sensor nodes to their geographical locations, and verify the legitimacy of a data report by checking whether the locations of the sensors endorsing the report are logical (e.g., the sensors should be close enough to each other to sense the same event). We propose two filtering schemes: The geographical information based false data filtering scheme (GFFS) which utilizes the absolute positions of sensors in the verification, and the neighbor information based false data filtering scheme (NFFS) which utilizes relative positions of sensors when absolute positions cannot be obtained. We theoretically analyze the filtering probability of the two proposed schemes, and evaluate their performance through extensive simulations. Simulation results show that, when there are totally ten nodes compromised in a 400 nodes network, the detection probability of collaborative false data injection attacks is higher than 97% in GFFS and NFFS, but is less than 7% in traditional false data filtering approaches such as SEF. © 2013 Elsevier Inc. All rights reserved.

Wang G.,Central South University | Liu Q.,Central South University | Wu J.,Temple University
Proceedings of the ACM Conference on Computer and Communications Security | Year: 2010

Cloud computing, as an emerging computing paradigm, enables users to remotely store their data into a cloud so as to enjoy scalable services on-demand. Especially for small and medium-sized enterprises with limited budgets, they can achieve cost savings and productivity enhancements by using cloud-based services to manage projects, to make collaborations, and the like. However, allowing cloud service providers (CSPs), which are not in the same trusted domains as enterprise users, to take care of confidential data, may raise potential security and privacy issues. To keep the sensitive user data confidential against untrusted CSPs, a natural way is to apply cryptographic approaches, by disclosing decryption keys only to authorized users. However, when enterprise users outsource confidential data for sharing on cloud servers, the adopted encryption system should not only support fine-grained access control, but also provide high performance, full delegation, and scalability, so as to best serve the needs of accessing data anytime and anywhere, delegating within enterprises, and achieving a dynamic set of users. In this paper, we propose a scheme to help enterprises to efficiently share confidential data on cloud servers. We achieve this goal by first combining the hierarchical identity-based encryption (HIBE) system and the ciphertext-policy attribute-based encryption (CP-ABE) system, and then making a performance-expressivity tradeoff, finally applying proxy re-encryption and lazy re-encryption to our scheme.

Liao J.-M.,Tulane University | Zhou X.,Tulane University | Zhang Y.,Central South University | Lu H.,Tulane University
Cell Cycle | Year: 2012

Since the discovery of miRNAs, a number of miRNAs have been identified as p53's transcriptional targets. Most of them are involved in regulation of the known p53 functions, such as cell cycle, apoptosis and senescence. Our recent study revealed miR-1246 as a novel target of p53 and its analogs p63 and p73 to suppress the expression of DYRK1A and consequently activate NFAT, both of which are associated with Down syndrome and possibly with tumorigenesis. This finding suggests that miR-1246 might serve as a likely link of the p53 family with Down syndrome. Here, we provide some prospective views on the potential role of the p53 family in Down syndrome via miR-1246 and propose a new p53-miR-1246-DYRK1A- NFAT pathway in cancer. © 2012 Landes Bioscience.

Chen X.,Central South University | Wang X.,Central South University | Wu D.D.,University of Toronto
Decision Support Systems | Year: 2010

In the process of resolving financing difficulties of small and medium enterprises (SMEs) in China, the measurement of credit risk of SMEs is a very challenging problem. In this paper we develop a novel model based on the original KMV model with tunable parameters to measure the credit risk of Chinese listed SMEs. By setting two credit warning lines to monitor the credit crisis of listed SMEs, we find that the predictive accuracy of adjusted KMV model is stable to the change of default points in Chinese listed SMEs, which is different from KMV Company's existing result. Our study shows that the credit risk of listed SMEs in China is relatively high and tends to increase during the chosen period from the year 2004 to 2006. We also find that the asset size has significant impact on credit risk and there are few credit risk fluctuations before and after the split share structure reform. © 2010 Elsevier B.V. All rights reserved.

Jiang W.,Central South University | Jiang W.,Temple University | Wang G.,Central South University | Wu J.,Temple University
Future Generation Computer Systems | Year: 2014

We propose a novel trust framework to address the issue of "Can Alice trust Bob on a service?" in large online social networks (OSNs). Many models have been proposed for constructing and calculating trust. However, two common shortcomings make them less practical, especially in large OSNs: the information used to construct trust is (1) usually too complicated to get or maintain, that is, it is resource consuming; and (2) usually subjective and changeable, which makes it vulnerable to vicious nodes. With those problems in mind, we focus on generating small trusted graphs for large OSNs, which can be used to make previous trust evaluation algorithms more efficient and practical. We show how to preprocess a social network (PSN) by developing a simple and practical user-domain-based trusted acquaintance chain discovery algorithm through using the small-world network characteristics of online social networks and taking advantage of "weak ties". Then, we present how to build a trust network (BTN) and generate a trusted graph (GTG) with the adjustable width breadth-first search algorithms. To validate the effectiveness of our work and to evaluate the quality of the generated trusted graph, we conduct many experiments with the real data set from Our work is the first that focuses on generating small trusted graphs for large online social networks, and we explore the stable and objective information (such as domain) for inferring trust. © 2013 Elsevier B.V. All rights reserved.

Wang M.,Central South University | Elhai J.D.,University of Toledo | Dai X.,Shenzhen University | Yao S.,Central South University
Journal of Anxiety Disorders | Year: 2012

The present study examined the invariance of four models of posttraumatic stress disorder symptoms (PTSD) across time through an analysis of symptom ratings from the PTSD Checklist-Civilian version. Participants included 403 junior middle school students recruited from Sichuan, China at 5 and 11 months after the 2008 Sichuan earthquake. Confirmatory factor analysis using measurement and structural invariance testing found that four tested models were non-invariant (i.e., different) over time on PTSD's variable intercepts (indicating symptom severity) and residual error variances, but were invariant on PTSD's factor loadings and structural parameters. The two 4-factor intercorrelated models and the newly proposed 5-factor model were superior to the model defined in DSM-IV; however, the best fitting model was the newest proposed 5-factor model. These findings extend our understanding of PTSD's factor structure that the factor structure may be quite stable over time. © 2011 Elsevier Ltd.

Zhu M.-X.,Central South University | Luo X.-X.,Central South University | Chen X.-H.,Central South University | Wu D.D.,University of Toronto
Information Sciences | Year: 2012

This paper proposes a fuzzy qualitative and quantitative softgoal interdependency graphs (FQQSIG) model for non-functional requirements (NFRs) correlations analysis in Trustworthy Software (TS), which is considered a critical issue by academia, government, and industry. First, the FQQSIG model constructs an NFRs criteria decomposition hierarchy graph in the complex TS situation. Subsequently, it draws on trapezoidal fuzzy number and introduces a simulation algorithm named RAGE (RAndom GEneration) to transform the qualitative degree of importance assessments on NFRs in the form of experts' fuzzy linguistic variables into quantitative values. Using a new algorithm named Relationship Matrix, this model can calculate all NFRs contribution values by which developers could make tradeoff decisions among NFRs competing alternatives. The credibility and advantages of the FQQSIG model are discussed and an example is given to illustrate the FQQSIG model. © 2011 Elsevier Inc. All rights reserved.

Lu Z.-H.,Central South University | Zhao Y.-G.,Kanagawa University
Journal of Constructional Steel Research | Year: 2010

In this paper, a total of 250 experimental tests of axially loaded circular concrete-filled steel tube (CFT) stub columns, published in the literature was summarized. The applicability of the current design codes such as ACI, Australian Standards, AISC, AIJ, Eurocode 4, DL/T and some available empirical models proposed by various researchers for calculating the axial capacity of circular CFT stub columns was examined using these experimental data. Based on the investigations, four new empirical models for predicting the axial capacity of circular CFT stub columns are proposed. The comparisons between the experimental results and the predictions of these models show that the proposed empirical models provide a direct, compact, and efficient representation of the ultimate strength of circular CFT stub columns made with not only normal strength but also high strength steel tubes and concrete. Finally, the limiting values of the maximum effective length, the compressive strength of concrete, the yield strength of steel tubes and the diameter-to-thickness for circular CFT stub columns with respect to the present empirical models are suggested. It is expected that engineers can easily use the present empirical models to estimate the axial capacities of circular CFT stub columns for engineering designs. © 2010 Elsevier Ltd. All rights reserved.

Wang G.,Central South University | Wu J.,Temple University
Future Generation Computer Systems | Year: 2011

Trust management is an extensively investigated topic. A lot of trust models and systems have been proposed in the literature. However, a universally agreed trust model is rarely seen due to the fact that trust is essentially subjective and different people may have different views on it. We focus on the personalization of trust in order to catch this subjective nature of trust. We propose a multi-dimensional evidence-based trust management system with multi-trusted paths (MeTrust for short) to conduct trust computation on any arbitrarily complex trusted graph. The trust computation in MeTrust is conducted at three tiers, namely, the node tier, the path tier, and the graph tier. At the node tier, we consider multi-dimensional trust. Users can define a primary dimension and alternative dimensions on their own and users can make their own privileged strategies and setup weights for different dimensions for trust computation. At the path tier, we propose to use the Frank t-norm for users to control the decay rate for trust combination, which can be tuned in between the minimum trust combination (there is no decay in terms of the path length) and the product trust combination (the decay is too fast when the path length is relatively large). At the graph tier, we propose GraphReduce, GraphAdjust, and WeightedAverage algorithms to simplify any arbitrarily complex trusted graph. We employ trust truncation and trust equivalence to guarantee that every link in the graph will be used exactly once for trust computation. We evaluated trust truncation ratio and trust success ratio through extensive experiments, which can serve as a guide for users to select from a wide spectrum of trust parameters for trust computation. © 2010 Elsevier B.V. All rights reserved.

Tan C.,Central South University | Wu D.D.,University of Toronto | Ma B.,Central South University
Expert Systems with Applications | Year: 2011

Linguistic preference relation is a useful tool for expressing preferences of decision makers in group decision making according to linguistic scales. But in the real decision problems, there usually exist interactive phenomena among the preference of decision makers, which makes it difficult to aggregate preference information by conventional additive aggregation operators. Thus, to approximate the human subjective preference evaluation process, it would be more suitable to apply non-additive measures tool without assuming additivity and independence. In this paper, based on λ-fuzzy measure, we consider dependence among subjective preference of decision makers to develop some new linguistic aggregation operators such as linguistic ordered geometric averaging operator and extended linguistic Choquet integral operator to aggregate the multiplicative linguistic preference relations and additive linguistic preference relations, respectively. Further, the procedure and algorithm of group decision making based on these new linguistic aggregation operators and linguistic preference relations are given. Finally, a supplier selection example is provided to illustrate the developed approaches. © 2011 Elsevier Ltd. All rights reserved.

Zhan X.,Central South University | Wang X.,Central South University | Desiderio D.M.,University of Tennessee Health Science Center
Oxidative Medicine and Cellular Longevity | Year: 2013

Oxidative stress is extensively associated with tumorigenesis. A series of studies on stable tyrosine nitration as a marker of oxidative damage were performed in human pituitary and adenoma. This paper reviews published research on the mass spectrometry characteristics of nitropeptides and nitroproteomics of pituitary controls and adenomas. The methodology used for nitroproteomics, the current status of human pituitary nitroproteomics studies, and the future perspectives are reviewed. Enrichment of those low-abundance endogenous nitroproteins from human tissues or body fluid samples is the first important step for nitroproteomics studies. Mass spectrometry is the essential approach to determine the amino acid sequence and locate the nitrotyrosine sites. Bioinformatics analyses, including protein domain and motif analyses, are needed to locate the nitrotyrosine site within the corresponding protein domains/motifs. Systems biology techniques, including pathway analysis, are necessary to discover signaling pathway networks involving nitroproteins from the systematically global point of view. Future quantitative nitroproteomics will discover pituitary adenoma-specific nitroprotein(s). Structural biology techniques such as X-ray crystallography analysis will solidly clarify the effects of tyrosine nitration on structure and functions of a protein. Those studies will eventually address the mechanisms and biological functions of tyrosine nitration in pituitary tumorigenesis and will discover nitroprotein biomarkers for pituitary adenomas and targets for drug design for pituitary adenoma therapy. © 2013 Xianquan Zhan et al.

Wang G.,Central South University | Wu J.,Temple University
Frontiers of Computer Science in China | Year: 2011

Web-based social networking is increasingly gaining popularity due to the rapid development of computer networking technologies. However, social networking applications still cannot obtain a wider acceptance by many users due to some unresolved issues, such as trust, security, and privacy. In social networks, trust is mainly studied whether a remote user behaves as expected by an interested user via other users, who are respectively named trustee, trustor, and recommenders. A trust graph consists of a trustor, a trustee, some recommenders, and the trust relationships between them. In this paper, we propose a novel FlowTrust approach to model a trust graph with network flows, and evaluate the maximum amount of trust that can flow through a trust graph using network flow theory. FlowTrust supports multi-dimensional trust. We use trust value and confidence level as two trust factors. We deduce four trust metrics from these two trust factors, which are maximum flow of trust value, maximum flow of confidence level, minimum cost of uncertainty with maximum flow of trust, and minimum cost of mistrust with maximum flow of confidence. We also propose three FlowTrust algorithms to normalize these four trust metrics. We compare our proposed FlowTrust approach with the existing RelTrust and CircuitTrust approaches. We show that all three approaches are comparable in terms of the inferred trust values. Therefore, FlowTrust is the best of the three since it also supports multi-dimensional trust. © 2011 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Liu Q.,Central South University | Liu Q.,Temple University | Wang G.,Central South University | Wu J.,Temple University
Information Sciences | Year: 2014

A fundamental approach for secure data sharing in a cloud environment is to let the data owner encrypt data before outsouring. To simultaneously achieve fine-grained access control on encrypted data and scalable user revocation, existing work combines attribute-based encryption (ABE) and proxy re-encryption (PRE) to delegate the cloud service provider (CSP) to execute re-encryption. However, the data owner should be online in order to send the PRE keys to the CSP in a timely fashion, to prevent the revoked user from accessing the future data. The delay of issuing the PRE keys may cause potential security risks. In this paper, we propose a time-based proxy re-encryption (TimePRE) scheme to allow a user's access right to expire automatically after a predetermined period of time. In this case, the data owner can be offline in the process of user revocations. The basic idea is to incorporate the concept of time into the combination of ABE and PRE. Specifically, each data is associated with an attribute-based access structure and an access time, and each user is identified by a set of attributes and a set of eligible time periods which denote the period of validity of the user's access right. Then, the data owner and the CSP are required to share a root secret key in advance, with which CSP can automatically update the access time of the data with the time that it receives a data access request. Therefore, given the re-encrypted ciphertext, only the users whose attributes satisfy the access structure and whose access rights are effective in the access time can recover corresponding data. © 2013 Elsevier Inc. All rights reserved.

Alt-Epping P.,University of Bern | Zhao C.,Central South University
Journal of Geochemical Exploration | Year: 2010

For a three-dimensional vertically-oriented fault zone, we consider the coupled effects of fluid flow, heat transfer and reactive mass transport, to investigate the patterns of fluid flow, temperature distribution, mineral alteration and chemically induced porosity changes. We show, analytically and numerically, that finger-like convection patterns can arise in a vertically-oriented fault zone. The onset and patterns of convective fluid flow are controlled by the Rayleigh number which is a function of the thermal properties of the fluid and the rock, the vertical temperature gradient, and the height and the permeability of the fault zone. Vigorous fluid flow causes low temperature gradients over a large region of the fault zone. In such a case, flow across lithological interfaces becomes the most important mechanism for the formation of sharp chemical reaction fronts. The degree of rock buffering, the extent and intensity of alteration, the alteration mineralogy and in some cases the formation of ore deposits are controlled by the magnitude of the flow velocity across these compositional interfaces in the rock. This indicates that alteration patterns along compositional boundaries in the rock may provide some insights into the convection pattern. The advective mass and heat exchanges between the fault zone and the wallrock depend on the permeability contrast between the fault zone and the wallrock. A high permeability contrast promotes focussed convective flow within the fault zone and diffusive exchange of heat and chemical reactants between the fault zone and the wallrock. However, a more gradual permeability change may lead to a regional-scale convective flow system where the flow pattern in the fault affects large-scale fluid flow, mass transport and chemical alteration in the wallrocks. © 2009 Elsevier B.V.

Xie K.,Tongji University | Wang X.,Tongji University | Huang H.,Central South University | Chen X.,Tongji University
Accident Analysis and Prevention | Year: 2013

Most traffic crashes in Chinese cities occur at signalized intersections. Research on the intersection safety problem in China is still in its early stage. The recent development of an advanced traffic information system in Shanghai enables in-depth intersection safety analyses using road design, traffic operation, and crash data. In Shanghai, the road network density is relatively high and the distance between signalized intersections is small, averaging about 200 m. Adjacent signalized intersections located along the same corridor share similar traffic flows, and signals are usually coordinated. Therefore, when studying intersection safety in Shanghai, it is essential to account for intersection correlations within corridors. In this study, data for 195 signalized intersections along 22 corridors in the urban areas of Shanghai were collected. Mean speeds and speed variances of corridors were acquired from taxis equipped with Global Positioning Systems (GPS). Bayesian hierarchical models were applied to identify crash risk factors at both the intersection and the corridor levels. Results showed that intersections along corridors with lower mean speeds were associated with fewer crashes than those with higher speeds, and those intersections along two-way roads, under elevated roads, and in close proximity to each other, tended to have higher crash frequencies. © 2012 Elsevier Ltd.

Jiang C.,Central South University | Liu X.-Y.,Los Alamos National Laboratory | Sickafus K.E.,Los Alamos National Laboratory
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Fission product incorporation in ceramic fuels has long been an active area of research. In this work, we consider a special case of xenon incorporation in ZrO2 in the framework of closed systems under extreme radiation conditions where thermal defects are less important than cascade driven defects. The energetics of a variety of defect configurations associated with xenon incorporation are considered. We use first-principles density-functional theory (DFT) calculations to predict the thermodynamic stability of xenon in different ZrO2 structural forms, including monoclinic, tetragonal, and yttrium-stabilized cubic ZrO2. Two defect configurations are found to dominate the fission gas incorporation process: xenon interstitial and oxygen substitutional configurations. In yttrium-stabilized cubic ZrO2, the pre-existing structural oxygen vacancies provide ideal sites for Xe incorporation since no oxygen Frenkel pairs need to be formed. The charge-transfer issue in oxides modeling is important in defects calculations. This issue has also been addressed through our supercell benchmark calculations. © 2011 American Physical Society.

Jiang M.,University of Georgia | Wei Q.,University of Georgia | Dong G.,University of Georgia | Komatsu M.,Tokyo Metropolitan Institute of Medical Science | And 3 more authors.
Kidney International | Year: 2012

Autophagy is induced in renal tubular cells during acute kidney injury; however, whether this is protective or injurious remains controversial. We address this question by pharmacologic and genetic blockade of autophagy using mouse models of cisplatin- and ischemia-reperfusion-induced acute kidney injury. Chloroquine, a pharmacological inhibitor of autophagy, blocked autophagic flux and enhanced acute kidney injury in both models. Rapamycin, however, activated autophagy and protected against cisplatin-induced acute kidney injury. We also established a renal proximal tubule-specific autophagy-related gene 7-knockout mouse model shown to be defective in both basal and cisplatin-induced autophagy in kidneys. Compared with wild-type littermates, these knockout mice were markedly more sensitive to cisplatin-induced acute kidney injury as indicated by renal functional loss, tissue damage, and apoptosis. Mechanistically, these knockout mice had heightened activation of p53 and c-Jun N terminal kinase, the signaling pathways contributing to cisplatin acute kidney injury. Proximal tubular cells isolated from the knockout mice were more sensitive to cisplatin-induced apoptosis than cells from wild-type mice. In addition, the knockout mice were more sensitive to renal ischemia-reperfusion injury than their wild-type littermates. Thus, our results establish a renoprotective role of tubular cell autophagy in acute kidney injury where it may interfere with cell killing mechanisms. © 2012 International Society of Nephrology.

Jiang C.,Central South University | Lin Z.,Los Alamos National Laboratory | Zhao Y.,Los Alamos National Laboratory
Scripta Materialia | Year: 2010

The possible crystal structures of transition metal nitrides M2N3 (M = V or Nb) were investigated using first principles calculations. We predict that the ground state structures of V2N3 and Nb2N3 are trigonal and orthorhombic, respectively, over a wide pressure range. Examinations of the thermodynamic stabilities of trigonal V2N3 and orthorhombic Nb2N3 with respect to phase decomposition suggest that they can be prepared under moderate pressure conditions. Elastic constant calculations indicated that both nitrides were mechanically stable and are potential candidates for hard materials. © 2010 Acta Materialia Inc.

Xie S.,Central South University | Zhou H.,Central South University | Zhou H.,Central South University of forestry and Technology
Thin-Walled Structures | Year: 2015

To improve the efficiency of the numerical simulation of the crushing of a honeycomb structure, the equivalent solid model of an aluminium honeycomb core was established. Comparison between the numerical simulation results and experimental evidence revealed that the numerical model of the honeycomb structure was effectively verified as representative. Secondly, the response surfaces for the variation of specific energy absorption (SEA) with side length l and thickness t of the aluminium foil were constructed by surrogate models. Then the relationship between SEA variation and the length l and thickness t of the aluminium foil was investigated. Results indicated that SEA increased with increasing t and decreased with increasing l. The optimum SEA and associated structural parameters (l=1.0 mm, and t=0.16 mm) of an aluminium honeycomb were obtained. ©2015 Elsevier Ltd. All rights reserved.

Jing H.,Xiangyang CSR Electrify Technology System Co. | Nian X.,Central South University
Dianwang Jishu/Power System Technology | Year: 2013

Failure mechanism of sub-modules of modular multilevel converter (MMC) under three operating modes and corresponding approaches are analyzed, and a novel protection strategy for sub-module by adding a protective thyristor to the topology of original sub-module is proposed to fast switch-off the faulty sub-module. Simulation results show that after the improvement of the topology of sub-module, the protection efficiency can be greatly improved and the ability to protect sub-module from failure is enhanced.

Chen R.,Central South University | Chen R.,University of Pittsburgh | Kang R.,University of Pittsburgh | Fan X.-G.,Central South University | Tang D.,University of Pittsburgh
Cell Death and Disease | Year: 2014

Histones and their post-translational modifications have key roles in chromatin remodeling and gene transcription. Besides intranuclear functions, histones act as damage-associated molecular pattern molecules when they are released into the extracellular space. Administration of exogenous histones to animals leads to systemic inflammatory and toxic responses through activating Toll-like receptors and inflammasome pathways. Anti-histone treatment (e.g., neutralizing antibodies, activated protein C, recombinant thrombomodulin, and heparin) protect mice against lethal endotoxemia, sepsis, ischemia/reperfusion injury, trauma, pancreatitis, peritonitis, stroke, coagulation, and thrombosis. In addition, elevated serum histone and nucleosome levels have been implicated in multiple pathophysiological processes and progression of diseases including autoimmune diseases, inflammatory diseases, and cancer. Therefore, extracellular histones could serve as biomarkers and novel therapeutic targets in human diseases. © 2014 Macmillan Publishers Limited All rights reserved.

Cai C.,Central South University | Liu Z.,Hong Kong Polytechnic University | Xia P.,Central South University | Dai W.,Central South University
GPS Solutions | Year: 2013

We develop a new approach for cycle slip detection and repair under high ionospheric activity using undifferenced dual-frequency GPS carrier phase observations. A forward and backward moving window averaging (FBMWA) algorithm and a second-order, time-difference phase ionospheric residual (STPIR) algorithm are integrated to jointly detect and repair cycle slips. The FBMWA algorithm is proposed to detect cycle slips from the widelane ambiguity of Melbourne-Wübbena linear combination observable. The FBMWA algorithm has the advantage of reducing the noise level of widelane ambiguities, even if the GPS data are observed under rapid ionospheric variations. Thus, the detection of slips of one cycle becomes possible. The STPIR algorithm can better remove the trend component of ionospheric variations compared to the normally used first-order, time-difference phase ionospheric residual method. The combination of STPIR and FBMWA algorithms can uniquely determine the cycle slips at both GPS L1 and L2 frequencies. The proposed approach has been tested using data collected under different levels of ionospheric activities with simulated cycle slips. The results indicate that this approach is effective even under active ionospheric conditions. © 2012 Springer-Verlag.

Li D.,Central South University | Li D.,Nanyang Technological University | Wong L.N.Y.,Nanyang Technological University
Rock Mechanics and Rock Engineering | Year: 2013

The development of the Brazilian disc test for determining indirect tensile strength and its applications in rock mechanics are reviewed herein. Based on the history of research on the Brazilian test by analytical, experimental, and numerical approaches, three research stages can be identified. Most of the early studies focused on the tensile stress distribution in Brazilian disc specimens, while ignoring the tensile strain distribution. The observation of different crack initiation positions in the Brazilian disc has drawn a lot of research interest from the rock mechanics community. A simple extension strain criterion was put forward by Stacey (Int J Rock Mech Min Sci Geomech Abstr 18(6):469-474, 1981) to account for extension crack initiation and propagation in rocks, although this is not widely used. In the present study, a linear elastic numerical model is constructed to study crack initiation in a 50-mm-diameter Brazilian disc using FLAC3D. The maximum tensile stress and the maximum tensile strain are both found to occur about 5 mm away from the two loading points along the compressed diameter of the disc, instead of at the center of the disc surface. Therefore, the crack initiation point of the Brazilian test for rocks may be located near the loading point when the tensile strain meets the maximum extension strain criterion, but at the surface center when the tensile stress meets the maximum tensile strength criterion. © 2012 Springer-Verlag.

Jiang Y.,Central South University | Liu M.,University of Tübingen
Granular Matter | Year: 2013

Proportional paths as summed up by the Goldscheider Rule (GR) - stating that given a constant strain rate, the evolution of the stress maintains the ratios of its components - is a characteristics of elasto-plastic motion in granular media. Barodesy, a constitutive relation proposed recently by Kolymbas, is a model that, with GR as input, successfully accounts for data from soil mechanical experiments. Granular solid hydrodynamics (GSH), a theory derived from general principles of physics and two assumptions about the basic behavior of granular media, is constructed to qualitatively account for a wide range of observation - from elastic waves over elasto-plastic deformation to rapid dense flow. In this paper, showing the close resemblance of results from Barodesy and GSH, we further validate GSH and provide an understanding for GR. © 2013 Springer-Verlag Berlin Heidelberg.

Hu J.,Central South University | Li Z.W.,Central South University | Ding X.L.,Hong Kong Polytechnic University | Zhu J.J.,Central South University | And 2 more authors.
Earth-Science Reviews | Year: 2014

One-dimensional measurement along the Line-Of-Sight (LOS) direction has greatly limited the capability of InSAR technique in the investigation of surface displacements and their dynamics. In recent years, great efforts have been made to resolve complete three-dimensional (3-D) displacements from InSAR measurements. This contribution is intended to provide a systematic review of the progress achieved in this field. Based on an analysis of the InSAR LOS measurements, we first cover two commonly used techniques, i.e., Offset-Tracking and multi-aperture InSAR (MAI), with which the surface displacement in the azimuth direction can be measured together with the LOS displacement. Several methods for mapping 3-D displacements using InSAR measurements are subsequently presented and categorized into three groups: (i) combination of multi-pass LOS and azimuth measurements; (ii) integration of InSAR and GPS data; and (iii) prior information assisted approaches. The strengths and weaknesses of each method are analyzed to show the applicability of each method to specific 3-D displacement mapping cases, in hope to provide a useful guidance in choosing a suitable approach accordingly. Finally, suggestions for resolving the challenging issues and outlook of future research are given. © 2014 Elsevier B.V.

Lv Y.,Central South University | Lv Y.,Nanjing Medical University | Wolf A.,University of Oxford | Wang X.,Central South University
General Hospital Psychiatry | Year: 2013

Objective: To investigate experienced stigma and self-stigma in patients with schizophrenia in mainland China. Methods: Ninety-five patients with schizophrenia, enrolled between January 2011 and March 2011, completed Chinese versions of two self-report questionnaires: the Internalized Stigma of Mental Illness (ISMI) scale and the Modified Consumer Experiences of Stigma Questionnaire (MCESQ). They also completed two other self-report questionnaires: the Social Support Rating Scale (SSRS) and the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire. Patients were also assessed by a senior psychiatrist using the Scale for Assessment of Positive Symptoms (SAPS) and the Scale for Assessment of Negative Symptoms (SANS).All analyses were performed using SPSS 17.0 and included descriptive statistics, correlation analysis and multiple linear regression. Results: On the ISMI, the percentage of participants who rated themselves above the mid-point of 2.5 (meaning high level of self-stigma) on subscales and overall score was 44.2% (n=42) for alienation, 14.7% (n=14) for stereotype endorsement, 25.3% (n=24) for perceived discrimination, 32.6% (n=31) for social withdrawal and 20.0% (n=19) on the overall score. On the MCESQ, the percentage of participants who rated themselves above the mid-point of 3.0 on subscales and overall score was 24.2% (n=23) for stigma, 1.1% (n=1) for discrimination and 1.1% (n=1) on the overall score. Some socioeconomic variables, but not positive or negative symptoms, were related to the severity of psychiatric stigma. Conclusions: Results document the seriousness of experienced stigma and self-stigma in persons with schizophrenia. Strategies are needed to improve how governments and persons with schizophrenia cope with stigma. © 2013 Elsevier Inc.

Jiang Y.,Central South University | Liu M.,University of Tübingen
Acta Mechanica | Year: 2014

A unified continuum-mechanical theory has been until now lacking for granular media, some believe it could not exist. Derived employing the hydrodynamic approach, Granular Solid Hydrodynamic is such a theory, though as yet a qualitative one. The behavior being accounted for includes static stress distribution, elastic wave, elasto-plastic motion, the critical state and rapid dense flow. The equations and application to a few typical experiments are presented here. © 2014 Springer-Verlag Wien.

Yang X.-L.,Central South University | Yin J.-H.,Hong Kong Polytechnic University
Rock Mechanics and Rock Engineering | Year: 2010

The upper bound theorem of limit analysis is employed to calculate the equivalent MC cohesion coefficient and friction angle to meet the demands of software written in terms of the Mohr-Coulomb (MC) failure criterion when the rock mass failure follows the modified HB failure criterion for slopes in limit state. A MC failure criterion, which is tangent to the actual modified HB failure criterion, is used to calculate the rate of external work and internal energy dissipation. The equivalent MC friction angle is obtained when the objective function is minimized. The equivalent MC friction angles and cohesion depend not only on the nonlinear HB failure criterion but also on the rock slope angles.

Zhou J.,Nanjing Medical University | Wang S.,Nanjing Medical University | Xia X.,Central South University
Current Eye Research | Year: 2012

Objective: Inflammatory reaction has been shown to involve the progress of type 2 (non-insulin-dependent) diabetes. We, therefore, examined the effects of inflammatory cytokines and angiogenic factors in the pathogenesis of proliferative diabetic retinopathy (PDR) in type 2 diabetes. Patients and methods: Vitreous fluid samples were obtained by vitrectomy from 62 eyes of PDR patients with type 2 diabetes and from 20 eyes of age-matched non-diabetic patients. The concentrations of interleukin 1 beta (IL1B), IL6, IL8, IL10, chemokine (C-C motif) ligand 2 (CCL2), endothelin 1 (EDN1), vascular endothelial growth factor (VEGF), and tumor necrosis factor (TNF) in the vitreous samples were measured by enzyme-linked immunosorbent assay (ELISA). Results: The concentrations of LI1B, IL6, IL8, CCL2, EDN1, VEGF, and TNF in the vitreous samples were considerably higher in PDR patients in comparison with the controls. However, the level of IL10 in PDR patients was similar to that obtained in the controls. Analysis of the correlations of the studied factors revealed the correlation of VEGF and IL6, VEGF and EDN1, IL8 and CCL2, and EDN1 and TNF in PDR patients. In addition, a significant positive correlation was observed between vitreous TNF as well as EDN1 and serum HbA1c levels in PDR patients. Conclusions: The inflammatory cytokines and angiogenic factors IL1B, IL6, IL8, CCL2, EDN1, VEGF, and TNF are increased in the vitreous of PDR patients without an increase in IL-10. These results add support to the role of inflammatory cytokines and angiogenic factors in the genesis of PDR. Understanding the implication of these cytokines may provide diagnostic tools and therapeutic targets for treatment and prevention of PDR. © 2012 Informa Healthcare USA, Inc.

Li H.,Central South University | Wu B.,Hong Kong Polytechnic University
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2013

Geo-information (GI) service automated composition according to user demands is a crucial task in spatial data infrastructures. State-of-the-art GI service composition approaches face serious limitations in terms of effectiveness and stability as the general GI processing service chain (GIPSC) must be generated from individual user specifications from scratch. This paper presents a novel approach called an adaptive geo-information service evolution (AgiSE) method which overcomes these limitations by adaptively reusing and modifying previously generated GIPSC. In this method, an influence domain minimisation (IDM) criterion is employed to modify the existing GIPSC to fit the new (changed) user demands through minimum revisions. The correction of local modification is ensured by process and integrity constraints. An innovative algorithm called influence domain pursuit is developed to find the optimised solution through a heuristic backward search based on the defined IDM. Experimental analysis shows the significant improvements of using AgiSE in GI services compared with existing traditional methods. The benefits of AgiSE are the improved efficiency of GI service composition and the improved executing stability of GIPSC which were achieved by reducing the service provider load. The AgiSE presented in this paper is crucial in reusing a general unified framework for GI service composition. © 2013 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).

Zhuang Q.,University of Pittsburgh | Zhuang Q.,Central South University | Lakkis F.G.,University of Pittsburgh
Kidney International | Year: 2015

This review summarizes emerging concepts related to the roles of dendritic cells (DCs) and innate immunity in organ transplant rejection. First, it highlights the primary role that recipient, rather than donor, DCs have in rejection and reviews their origin and function in the transplanted kidney. Second, it introduces the novel concept that recognition of allogeneic non-self by host monocytes (referred to here as innate allorecognition) is necessary for initiating rejection by inducing monocyte differentiation into mature, antigen-presenting DCs. Both concepts provide opportunities for preventing rejection by targeting monocytes or DCs. © 2015 International Society of Nephrology.

Li L.,Guangzhou Medical College | Chen L.-Z.,Central South University
Asian Pacific Journal of Cancer Prevention | Year: 2012

Purpose: To explore the relationship between auxiliary lymph node metastasis and clinical features, and to identify the factors that affect metastasis occurrence. Methods: A total of 164 cases of primary breast cancer were selected to investigate features such as age, concomitant chronic disease and pathologic diagnosis. Immunohistochemistry was used to detect the expression of the estrogen receptor (ER) and CerbB-2. Logistic regression was employed to analyze the factors that affect the incidence of lymph node metastases. Results: The incidence of lymph node metastases was 46.3% among elderly patients with breast cancer. Based on logistic regression, chronic disease, scale of tumor, age, and ER expression affected the occurrence of lymph node metastases; the ORs were 3.05, 2.18, 0.34, and 3.83, respectively. Between different pathologic diagnoses and the risk factors, the OR scores were 12.7 and 8.02, respectively, for aggressive ductal carcinoma and aggressive lobular carcinoma auxiliary lymph node metastases. Conclusion: The incidence of lymph node metastases is affected by chronic disease, scale of tumor, age, ER expression and pathologic diagnosis.

Zhu F.,Central South University | Zhang L.,Guangzhou Medical College | Ding Y.-Q.,Central South University | Zhao J.,Central South University | And 2 more authors.
Brain, Behavior, and Immunity | Year: 2014

Several lines of evidence have suggested that the dysregulation of immune system is involved in the pathogenesis of schizophrenia. Microglia are the resident macrophage of the brain and the major player in innate immunity in the brain. We hypothesized that microglia activation may be closely associated with the neuropathology of schizophrenia. Neonatal intrahippocampal injection of lipopolysaccharide (LPS), an activator of microglia, was performed in rats at postnatal day 7 (PD7), and they were separately treated with saline or minocycline for consecutive 3. days. Behavioral changes (locomotor activity, social interaction and prepulse inhibition) were examined in adulthood, and the number of microglia was assessed using immunohistochemistry at PD9, PD21 and PD67. The adult rats in LPS-injected group showed obvious behavioral alterations (deficits in social behavior and prepulse inhibition) and a persistently dramatic increase of number of activated microglial cells in the hippocampus, cerebral cortex and thalamus compared to those in saline-injected group. Interestingly, pretreatment with minocycline could significantly rescue the behavioral deficits and prevent microglia activation. Our results suggest that neonatal intrahippocampal LPS injection may serve as a potential schizophrenia animal model, and inhibition of microglia activation may be a potential treatment strategy for schizophrenia. © 2014 Elsevier Inc.

Jiang M.,Hong Kong Polytechnic University | Ding X.,Hong Kong Polytechnic University | Li Z.,Central South University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

The coherence of radar echoes is a fundamental observable in interferometric synthetic aperture radar (InSAR) measurements. It provides a quantitative measure of the scattering properties of imaged surfaces and therefore is widely applied to study the physical processes of the Earth. However, unfortunately, the estimated coherence values are often biased due to various reasons such as radar signal nonstationarity and the bias in the estimators used. In this paper, we focus on multitemporal InSAR coherence estimation and present a hybrid approach that mitigates effectively the errors in the estimation. The proposed approach is almost completely self-adaptive and workable for both Gaussian and non-Gaussian SAR scenes. Moreover, the bias of the sample coherence can be mitigated with even only several samples included for a given pixel. Therefore, it is a more pragmatic method for accurate coherence estimation and can be applied actually. Different data sets are used to test the proposed method and demonstrate its advantages. © 1980-2012 IEEE.

Chen X.,Hong Kong Polytechnic University | Xiang S.,Central South University
Mathematical Programming | Year: 2011

Using the least element solution of the P0 and Z matrix linear complementarity problem (LCP), we define an implicit solution function for linear complementarity constraints (LCC). We show that the sequence of solution functions defined by the unique solution of the regularized LCP is monotonically increasing and converges to the implicit solution function as the regularization parameter goes down to zero. Moreover, each component of the implicit solution function is convex. We find that the solution set of the irreducible P0 and Z matrix LCP can be represented by the least element solution and a Perron-Frobenius eigenvector. These results are applied to convex reformulation of mathematical programs with P0 and Z matrix LCC. Preliminary numerical results show the effectiveness and the efficiency of the reformulation. © 2009 Springer and Mathematical Programming Society.

Yu Y.,Beijing Jiaotong University | Yu Y.,City University of Hong Kong | Li H.-X.,Central South University | Li H.-X.,City University of Hong Kong
Nonlinear Analysis: Real World Applications | Year: 2011

In this paper, the adaptive backstepping design is proposed for the full state hybrid projective synchronization between two different chaotic systems with fully unknown parameters. Based on the design, the synchronization of two uncertain chaotic systems is realized only by using one controller, and the unknown parameters are identified through the corresponding parameter update laws. The uncertain GenesioTesi chaotic system and Lorenz system are chosen as examples for detailed description of the method. Finally, some numerical simulations are given to illustrate the effectiveness of the proposed method. © 2010 Published by Elsevier Ltd. All rights reserved.

Du C.,Central South University | Du C.,Inner Mongolia University | Yang H.,Central South University
Journal of Colloid and Interface Science | Year: 2012

Aluminum-containing hexagonally ordered mesoporous silica Al-MCM-41 was synthesized by hydrothermal treatment of leached products produced by pre-grinding and subsequent acid leaching of natural kaolin, without addition of silica or aluminum regents. The resulting Al-MCM-41 had a high surface area of 1041m 2/g, a pore volume of 0.97mL/g, and an average pore diameter of 3.7nm with narrow pore size distribution centered at 2.7nm. During the synthesis process of Al-MCM-41 from natural kaolin, the evolutions of chemical environments for Si and Al atoms should be emphasized. Wide angle X-ray diffraction (WAXRD), high-resolution transmission electron micrographs (HRTEMs), solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR), Fourier transform infrared spectroscopy (FT-IR) were used to trace the variations of chemical structures. Pretreatment of grinding and subsequent acid leaching acted as an important role in the whole synthesis process. NMR spectroscopy showed that Q 3 structure (Si(SiO) 3(OH)), condensed Q 4 framework structure (Si(SiO) 4), also the octahedral and tetrahedral Al existed in the leached sample and Al-MCM-41, with higher chemical contents of Q 4 structure and the octahedral Al in final product Al-MCM-41 than those in the leached sample. A possible mechanism for the formation of Al-MCM-41 from natural kaolin was suggested. © 2011 Elsevier Inc.

Guo Y.,Central South University | Guo Y.,Nanyang Technological University | Gui W.,Central South University | Yang C.,Central South University | Xie L.,Nanyang Technological University
Automatica | Year: 2012

In a reset control system, reset actions are usually triggered whenever a continuous signal crosses a hyperplane. In the computer-based implementation, however, the continuous triggering signal is sampled and the triggering condition is then replaced by a discrete-time counterpart. In this work, we are concerned with the stability analysis and design of reset control systems based directly on discrete-time triggering conditions. First, a relationship between reset control systems and switched systems is established and some stability criteria are then obtained. Second, it is revealed through an example that a well-designed reset control system can be regarded as a hybrid system combining an underdamped baseline system with an overdamped reset mode. The reset matrix, which is assumed to be zero in general, can be adjusted to increase the damping ratio and thus further improve the transient performance. Based on this observation, a design guideline for single-input and single-output (SISO) systems is proposed. Lastly, a hard disk drive example is investigated to demonstrate the proposed design procedure. © 2012 Elsevier Ltd. All rights reserved.

Chen X.,Hong Kong Polytechnic University | Xiang S.,Central South University
Mathematical Programming | Year: 2013

We propose a generalized Newton method for solving the system of nonlinear equations with linear complementarity constraints in the implicit or semi-implicit time-stepping scheme for differential linear complementarity systems (DLCS). We choose a specific solution from the solution set of the linear complementarity constraints to define a locally Lipschitz continuous right-hand-side function in the differential equation. Moreover, we present a simple formula to compute an element in the Clarke generalized Jacobian of the solution function. We show that the implicit or semi-implicit time-stepping scheme using the generalized Newton method can be applied to a class of DLCS including the nondegenerate matrix DLCS and hidden Z-matrix DLCS, and has a superlinear convergence rate. To illustrate our approach, we show that choosing the least-element solution from the solution set of the Z-matrix linear complementarity constraints can define a Lipschitz continuous right-hand-side function with a computable Lipschitz constant. The Lipschitz constant helps us to choose the step size of the time-stepping scheme and guarantee the convergence. © 2012 Springer and Mathematical Optimization Society.

Jiang Y.,Central South University | Liu M.,University of Tübingen
AIP Conference Proceedings | Year: 2013

Granular solid hydrodynamics (GSH) is employed to account for granular rheology, both the rate-controlled one, smoothly extending from the critical state to the Bagnold regime, and the stress-controlled one that is discontinuous and hysteretic. Employing GSH, it is shown that a quiescent state is stable below the smaller jamming stress and instable above the larger fluidization stress, with values in between being metastable; also, that the MiDi relation, appropriate for rigid grains, needs to be rectified, because real granular media, with a sound velocity one to three times that of air, are soft. © 2013 AIP Publishing LLC.

Wu H.B.,Nanyang Technological University | Pan A.,Nanyang Technological University | Pan A.,Central South University | Hng H.H.,Nanyang Technological University | Lou X.W.,Nanyang Technological University
Advanced Functional Materials | Year: 2013

In this work, rattle-type ball-in-ball V2O5 hollow microspheres are controllably synthesized with the assistance of carbon colloidal spheres as hard templates. Carbon spheres@vanadium-precursor (CS@V) core-shell composite microspheres are first prepared through a one-step solvothermal method. The composition of solvent for the solvothermal synthesis has great influence on the morphology and structure of the vanadium-precursor shells. V2O5 hollow microspheres with various shell architectures can be obtained after removing the carbon microspheres by calcination in air. Moreover, the interior hollow shell can be tailored by varying the temperature ramping rate and calcination temperature. The rattle-type V2O5 hollow microspheres are evaluated as a cathode material for lithium-ion batteries, which manifest high specific discharge capacity, good cycling stability and rate capability. Rattle-type V2O5 ball-in-ball hollow microspheres are controllably synthesized using carbon spheres as hard templates. Carbon spheres@vanadium- precursor (CS@V) core-shell composite microspheres with controllable morphology and structure are first prepared through a one-step solvothermal method. Rattle-type V2O5 hollow microspheres with various structures can be obtained after removing the carbon microspheres by calcination in air. When evaluated as a cathode material for lithium-ion batteries, the rattle-type V2O5 hollow microspheres manifest high specific capacity, good cycling stability and rate capability. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li D.,Nanyang Technological University | Li D.,Central South University | Wong L.N.Y.,Nanyang Technological University
Rock Mechanics and Rock Engineering | Year: 2013

The point load test has been considered as a cheap and useful testing method to estimate the strengths of rocks due to its ease of testing, simplicity of specimen preparation, and possible field application. An underground oil storage rock cavern is under construction in Singapore. The strength of surrounding rock mass is very high, which favors the stability of the excavation. The tested specimens have a nominal diameter of 50 mm, except the nine specimens cored from rock block R2, of which the nominal diameter is 45 mm. The length of the specimens ranges from approximately 80 to 100 mm for diametral tests and about 40 to 50 mm for axial tests. Calcite in-filling is observed along the joint planes in some meta-sandstone specimens, in which calcite veins and scattered pyrite grains are also observed.

Wu F.,Georgia Institute of Technology | Wu F.,Central South University | Magasinski A.,Georgia Institute of Technology | Yushin G.,Georgia Institute of Technology
Journal of Materials Chemistry A | Year: 2014

In order to achieve high capacity utilization and high rate performance of lithium sulfide (Li2S) cathode materials, it is critical to identify scalable methods for low-cost preparation of nanostructured Li2S or Li2S-carbon composites. Here, we report on the preparation and characterization of nanoporous Li2S and multiwalled (MW) carbon nanotube (CNT)-linked Li2S powders, prepared for the first time via a versatile solution-based method. The addition of MWCNTs enhances electrical conductivity and structural stability of the Li2S-based cathodes and reduces polarization of cells operating at high current densities. The nanostructured Li2S-based cathodes containing 20 wt% MWCNT showed promising discharge capacities of up to ∼1050 mA h g-1 S at a slow rate of C/20 and ∼800 mA h g-1 S at a C/2 rate. Quite remarkably, without any electrolyte additives (such as polysulfides or lithium nitrate) MWCNT-linked Li2S cathodes demonstrated up to ∼90% capacity retention after 100 cycles in half cells (vs. Li foil) at a C/5 and C/10 rates. This journal is © the Partner Organisations 2014.

Zou J.-P.,Central South University | Wang R.-Z.,University of British Columbia
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2012

Vertically orientated TiO 2 nanotube array with diameters ranging from 60 up to 80 nm and length of 4 μm was grown on titanium by anodization. Crack initiation, propagation and saturation were studied using the substrate straining test. The results show that annealing obviously modifies the interfaces. With the increase of tensile strain, cracks in TiO 2 nanotube films propagate rapidly and reach the saturation within a narrow strain gap. Interfacial shear strengths of TiO 2 nanotube films without annealing, with 250°C annealing and with 400°C annealing can be estimated as 163.3, 370.2 and 684.5 MPa, respectively. The critical energy release rates of TiO 2 nanotube films are calculated as 49.6, 102.6 and 392.7 J/m 2, respectively. The fracture toughnesses of TiO 2 nanotube films are estimated as 0.996, 1.433 and 2.803 MPa·m 1/2, respectively. The interfacial bonding mechanism of TiO 2 nanotube film is chemical bonding. © 2012 The Nonferrous Metals Society of China.

Nitta N.,Georgia Institute of Technology | Wu F.,Georgia Institute of Technology | Wu F.,Central South University | Lee J.T.,Georgia Institute of Technology | Yushin G.,Georgia Institute of Technology
Materials Today | Year: 2015

This review covers key technological developments and scientific challenges for a broad range of Li-ion battery electrodes. Periodic table and potential/capacity plots are used to compare many families of suitable materials. Performance characteristics, current limitations, and recent breakthroughs in the development of commercial intercalation materials such as lithium cobalt oxide (LCO), lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LFP), lithium titanium oxide (LTO) and others are contrasted with that of conversion materials, such as alloying anodes (Si, Ge, Sn, etc.), chalcogenides (S, Se, Te), and metal halides (F, Cl, Br, I). New polyanion cathode materials are also discussed. The cost, abundance, safety, Li and electron transport, volumetric expansion, material dissolution, and surface reactions for each type of electrode materials are described. Both general and specific strategies to overcome the current challenges are covered and categorized. © 2014 The Authors. Published by Elsevier Ltd.

Qu F.,Central South University | Qu F.,Qufu Normal University | Li T.,Central South University | Yang M.,Central South University
Biosensors and Bioelectronics | Year: 2011

A new colorimetric immunoassay for the detection of cancer biomarker prostate specific antigen (PSA) was developed based on the intrinsic peroxidase activity of graphene oxide (GO). GO can catalyze the reaction of hydroquinone in the presence of H 2O 2 to produce a brown color solution. Secondary antibody (Ab 2) functionalized GO (GO-Ab 2) was used as label for the immunoassay, while magnetic bead (MB) was selected to immobilize primary anti-PSA antibody (Ab 1). In the presence of PSA, an immunocomplex, sandwiching the antigen protein, is formed between the GO-Ab 2 and MB-Ab 1. With the separation of the immunocomplex using an external magnetic field, different amounts of GO-Ab 2 in the solution were mixed with hydroquinone and H 2O 2 solution and displaying colors. Different colors corresponding to different concentrations of PSA can be directly detected with eyes. Such a simple immunoassay holds great potential as sensitive, selective and point-of-care (POC) tool for clinical diagnosis of cancer biomarkers. © 2011 Elsevier B.V.

Wu F.,Georgia Institute of Technology | Lee J.T.,Georgia Institute of Technology | Zhao E.,Georgia Institute of Technology | Zhang B.,Central South University | Yushin G.,Georgia Institute of Technology
ACS Nano | Year: 2016

Lithium sulfide (Li2S) with a high theoretical specific capacity of 1166mAh g-1 is a promising cathode material for next-generation Li-S batteries with high specific energy. However, low conductivity of Li2S and polysulfide dissolution during cycling are known to limit the rate performance and cycle life of these batteries. Here, we report on the successful development and application of a nanocomposite cathode comprising graphene covered by Li2S nanoparticles and protected from undesirable interactions with electrolytes. We used a modification of our previously reported low cost, scalable, and high-Throughput solution-based method to deposit Li2S on graphene. A dropwise infiltration allowed us to keep the size of the heterogeneously nucleated Li2S particles smaller and more uniform than what we previously achieved. This, in turn, increased capacity utilization and contributed to improved rate performance and stability. The use of a highly conductive graphene backbone further increased cell rate performance. A synergetic combination of a protective layer vapor-deposited on the material during synthesis and in situ formed protective surface layer allowed us to retain 97% of the initial capacity of 1040 mAh gs -1 at C/2 after over 700 cycles in the assembled cells. The achieved combination of high rate performance and ultrahigh stability is very promising. © 2015 American Chemical Society.

Deng Y.,Central South University | Yin Z.,Central South University | Cong F.,Northeast Light Alloy Co.
Intermetallics | Year: 2012

Intermetallic phase evolution of 7050 aluminum alloy during homogenization was investigated in detail by optical microscopy, scanning electron microscopy, energy dispersive spectrometry, differential scanning calorimetry, electron probe micro-analysis and X-ray diffraction methods. The results show that severe dendritic segregation exists in as-cast alloy. The dissolvable intermetallic phases in as-cast alloy consist of equilibrium η (MgZn 2) phase, Cu and Mg enriched non-equilibrium aluminides and Cu enriched non-equilibrium aluminides. During homogenization, Cu and Mg enriched non-equilibrium aluminides, Cu enriched non-equilibrium aluminides and η (MgZn 2) phase gradually dissolve into matrix. Equilibrium S (Al 2CuMg) intermetallic phase nucleates and grows along the grain boundaries, and it disappears completely after multi-step homogenization. The proper homogenization processing is 400°C × 10 h step470°C × 24 h step485°C × 4 h, which is consistent with the results of homogenizing kinetic analysis. © 2012 Elsevier Ltd. All rights reserved.

Zhao C.,Central South University | Hobbs B.E.,University of Western Australia | Ord A.,University of Western Australia
International Journal for Numerical and Analytical Methods in Geomechanics | Year: 2013

SUMMARY: This paper presents an instability theory that can be used to understand the fundamental behavior of an acidization dissolution front when it propagates in fluid-saturated carbonate rocks. The proposed theory includes two fundamental concepts, namely the intrinsic time and length of an acidization dissolution system, and a theoretical criterion that involves the comparison of the Zhao number and its critical value of the acidization dissolution system. The intrinsic time is used to determine the time scale at which the acidization dissolution front is formed, while the intrinsic length is used to determine the length scale at which the instability of the acidization dissolution front can be initiated. Under the assumption that the acidization dissolution reaction is a fast process, the critical Zhao number, which is used to assess the instability likelihood of an acidization dissolution front propagating in fluid-saturated carbonate rocks, has been derived in a strictly mathematical manner. Based on the proposed instability theory of a propagating acidization dissolution front, it has been theoretically recognized that: (i) the increase of the mineral dissolution ratio can stabilize the acidization dissolution front in fluid-saturated carbonate rocks; (ii) the increase of the final porosity of the carbonate rock can destabilize the acidization dissolution front, while the increase of the initial porosity can stabilize the acidization dissolution front in fluid-saturated carbonate rocks; (iii) the increase of the mineral dissolution ratio can cause an increase in the dimensionless propagation speed of the acidization dissolution front; (iv) the increase of the initial porosity can enable the acidization dissolution front to propagate faster, while the increase of the final porosity can enable the acidization dissolution front to propagate slower in the acidization dissolution system. © 2012 John Wiley & Sons, Ltd.

Zhao C.,Central South University | Hobbs B.E.,University of Western Australia | Ord A.,University of Western Australia
International Journal for Numerical Methods in Engineering | Year: 2015

This paper primarily deals with the computational aspects of chemical dissolution-front instability problems in two-dimensional fluid-saturated porous media under non-isothermal conditions. After the dimensionless governing partial differential equations of the non-isothermal chemical dissolution-front instability problem are briefly described, the formulation of a computational procedure, which contains a combination of using the finite difference and finite element method, is derived for simulating the morphological evolution of chemical dissolution fronts in the non-isothermal chemical dissolution system within two-dimensional fluid-saturated porous media. To ensure the correctness and accuracy of the numerical solutions, the proposed computational procedure is verified through comparing the numerical solutions with the analytical solutions for a benchmark problem. As an application example, the verified computational procedure is then used to simulate the morphological evolution of chemical dissolution fronts in the supercritical non-isothermal chemical dissolution system. The related numerical results have demonstrated the following: (1) the proposed computational procedure can produce accurate numerical solutions for the planar chemical dissolution-front propagation problem in the non-isothermal chemical dissolution system consisting of a fluid-saturated porous medium; (2) the Zhao number has a significant effect not only on the dimensionless propagation speed of the chemical dissolution front but also on the distribution patterns of the dimensionless temperature, dimensionless pore-fluid pressure, and dimensionless chemical-species concentration in a non-isothermal chemical dissolution system; (3) once the finger penetrates the whole computational domain, the dimensionless pore-fluid pressure decreases drastically in the non-isothermal chemical dissolution system. © 2014 John Wiley & Sons, Ltd.

Zhao C.,Central South University | Hobbs B.E.,University of Western Australia | Ord A.,University of Western Australia
International Journal for Numerical and Analytical Methods in Geomechanics | Year: 2015

This paper mainly deals with the theoretical aspects of chemical dissolution-front instability problems in two-dimensional fluid-saturated porous media under non-isothermal conditions. In the case of the mineral dissolution ratio (that is defined as the ratio of the dissolved-mineral equilibrium concentration in the pore fluid to the molar concentration of the dissolvable mineral in the solid matrix of the fluid-saturated porous medium) approaching zero, the corresponding critical condition has been mathematically derived when temperature variation effects are considered. As a complementary tool, the computational simulation method is used to simulate the morphological evolution of chemical dissolution fronts in two-dimensional fluid-saturated porous media under non-isothermal conditions. The related theoretical and numerical results have demonstrated that: (i) a temperature increase in a non-isothermal chemical dissolution system can have some influence on the propagation speed of the planar chemical dissolution front in the system. Generally, the chemical dissolution front in the non-isothermal chemical dissolution system propagates slower than that in the counterpart isothermal chemical dissolution system when the temperature of the non-isothermal chemical dissolution system is higher than that of the counterpart isothermal chemical dissolution system; (ii) a temperature increase in the non-isothermal chemical dissolution system can stabilize the chemical dissolution front propagating in the system, because it can cause a decrease in the Zhao number of the system but does not affect the critical Zhao number of the system; and (iii) the temperature gradient in the upstream direction of a chemical dissolution front is smaller than that in the downstream direction of the chemical dissolution front when the non-isothermal chemical dissolution system is supercritical. © 2014 John Wiley & Sons, Ltd.

Zhao C.,Central South University | Hobbs B.E.,University of Western Australia | Ord A.,University of Western Australia
Journal of Contaminant Hydrology | Year: 2012

The main purpose of this paper is to investigate the effects of different domain shapes in general and trapezoidal domain shape in particular on the morphological evolution of nonaqueous phase liquid (NAPL) dissolution fronts in two-dimensional fluid-saturated porous media. After the governing equations of NAPL dissolution problems are briefly described, the numerical procedure consisting of a combination of the finite element and finite difference methods is used to solve these equations. The related numerical simulation results have demonstrated that: (1) domain shapes have a significant effect on both the propagating speed and the morphological evolution pattern of a NAPL dissolution front in the fluid-saturated porous medium; (2) an increase in the divergent angle of a trapezoidal domain can lead to a decrease in the propagating speed of the NAPL dissolution front; (3) the morphological evolution pattern of the NAPL dissolution front in a rectangular domain is remarkably different from that in a trapezoidal domain of a large divergent angle; (4) for a rectangular domain, the simplified dispersion model, which is commonly used in the theoretical analysis and numerical simulation, is valid for solving NAPL dissolution instability problems in fluid-saturated porous media; and (5) compared with diverging flow (when the trapezoidal domain is inclined outward), converging flow (when the trapezoidal domain is inclined inward) can enhance the growth of NAPL fingers, indicating that pump-and-treat systems by extracting contaminated groundwater might enhance NAPL dissolution fingering and lead to less uniform dissolution fronts. © 2012 Elsevier B.V.

Zhou S.,Central South University | Solana J.R.,University of Cantabria
Journal of Physical Chemistry B | Year: 2013

The first three coefficients of the high temperature series expansion (HTSE) of the Helmholtz free energy for a number of simple potential models with hard-sphere cores plus continuous tails are obtained for the first time from Monte Carlo simulations. The potential models considered include Square-well, Sutherland, attractive Yukawa, and triangle-well with different potential ranges, as well as a model potential qualitatively resembling the depletion potential in colloidal dispersions. The simulation data are used to evaluate performance of a recent coupling parameter series expansion (CPSE) in calculating for these coefficients, and a traditional macroscopic compressibility approximation (MCA) for the second-order coefficient only. A comprehensive comparison based on these coefficients from the two theoretical approaches and simulations enables one to conclude that (i) unlike one common experience that the widely used MCA usually underestimates the second-order coefficient, the MCA can both overestimate and underestimate the second-order coefficient, and worsens as the range of the potential decreases; and (ii) in contrast, the CPSE not only reproduce the trends in the density dependence of the perturbation coefficients, even the third one, observed in the simulations, but also the agreement is quantitative in most cases, and this clearly highlights the potential of the CPSE in providing accurate estimations for the higher-order coefficients, thus giving rise to an accurate higher-order HTSE. © 2013 American Chemical Society.

Guo Y.,Central South University | Sawalha A.H.,University of Michigan | Lu Q.,Central South University
Clinical Immunology | Year: 2014

The current treatments of systemic lupus erythematosus (SLE) have been based on the use of immunosuppressive drugs which are linked to serious side effects. The more effective therapeutic approaches with minimal or no side effects for SLE patients are hard to develop, mainly due to the complexity of the disease. The discovery of pharmacoepigenetics provides a new way to solve this problem. Epigenetic modifications can influence drug efficacy by altering gene expression via changing chromatin structure. Although still in early development, epigenetic studies in SLE are expected to reveal novel therapeutic targets and disease biomarkers in autoimmunity. For example, miRNAs, which have been identified to govern many genes including drug targets, are altered in disease development and after drug administration. This review aims to present an overview of current epigenetic mechanisms involved in the pathogenesis of SLE, and discuss their potential roles in clinical and pharmacological applications. © 2014.

Li X.,Central South University | Dong L.,Central South University | Dong L.,University of Western Australia
AIP Advances | Year: 2014

This paper presents an efficient closed-form solution (ECS) for acoustic emission(AE) source location in three-dimensional structures using time difference of arrival (TDOA) measurements from N receivers, N ≥ 6. The nonlinear location equations of TDOA are simplified to linear equations. The unique analytical solution of AE sources for unknown velocity system is obtained by solving the linear equations. The proposed ECS method successfully solved the problems of location errors resulting from measured deviations of velocity as well as the existence and multiplicity of solutions induced by calculations of square roots in existed close-form methods. © 2014 Author(s).

Li P.,Zhejiang University | Li H.,Central South University | Wu M.,Central South University
Information Sciences | Year: 2013

Multi-label classification has attracted an increasing amount of attention in recent years. To this end, many algorithms have been developed to classify multi-label data in an effective manner. However, they usually do not consider the pairwise relations indicated by sample labels, which actually play important roles in multi-label classification. Inspired by this, we naturally extend the traditional pairwise constraints to the multi-label scenario via a flexible thresholding scheme. Moreover, to improve the generalization ability of the classifier, we adopt a boosting-like strategy to construct a multi-label ensemble from a group of base classifiers. To achieve these goals, this paper presents a novel multi-label classification framework named Variable Pairwise Constraint projection for Multi-label Ensemble (VPCME). Specifically, we take advantage of the variable pairwise constraint projection to learn a lower-dimensional data representation, which preserves the correlations between samples and labels. Thereafter, the base classifiers are trained in the new data space. For the boosting-like strategy, we employ both the variable pairwise constraints and the bootstrap steps to diversify the base classifiers. Empirical studies have shown the superiority of the proposed method in comparison with other approaches. © 2012 Elsevier Inc. All rights reserved.

Chen D.,Central South University | Zhang Y.-J.,Rush University | Zhu K.-W.,Central South University | Wang W.-C.,Central South University
Tumor Biology | Year: 2013

Vascular endothelial growth factor (VEGF) plays an important role in the tumor angiogenesis, and its expression has been supposed to be a biomarker of prognosis in patients with osteosarcoma. There are many studies assessing the prognostic role of VEGF expression in osteosarcoma, and no consistent outcomes are reported. To provide a comprehensive assessment of the prognostic role of VEGF expression, we performed a systematic review and meta-analysis of published studies. We assessed the effect of VEGF expression on the overall survival rate and the disease-free survival rate by calculating the pooled odds ratio (OR) with corresponding 95 % confidence interval (95 %CI). Finally, 12 studies with a total of 559 osteosarcoma patients were included into the systematic review and meta-analysis. Compared with osteosarcoma patients with low or negative VEGF expression, patients with high VEGF expression were obviously associated with lower disease-free survival (OR = 0.25, 95 %CI 0.11-0.58, P = 0.001, I 2 = 56.4 %). In addition, patients with high VEGF expression were obviously associated with lower overall survival (OR = 0.22, 95 %CI 0.13-0.35, P < 0.001, I 2 = 0.0 %). Therefore, the findings from this systematic review suggest that VEGF expression is an effective biomarker of prognosis in patients with osteosarcoma. © 2013 International Society of Oncology and BioMarkers (ISOBM).

Liu Y.,Montana State University | Zhang L.,Central South University
Scripta Materialia | Year: 2010

In order to predict the phase boundary dimension between two phase regions, Palatnik and Landau put forward the contact rule. Later, Zhao proposed phase boundary rules for T - xi multicomponent phase diagrams. In this study, the contact rule and phase boundary rules for T - xi multicomponent phase diagrams are derived from a geometric point of view, which contributes to a comprehensive understanding of the topological relations. The proposed formulas in this work differ slightly from those of Zhao, but can account for more geometric relations.

Peng S.,Zhaoqing University | Wang G.,Central South University | Yu S.,Deakin University
Journal of Computer and System Sciences | Year: 2013

Smartphones combine the communication capabilities of cellphones and the functions of PDA (personal digital assistant), which enable us to access a large variety of ubiquitous services, such as surfing the web, sending/receiving emails, MMS, and online shopping. However, the availability of these services provided by smartphones increases the vulnerability to worm attacks. In addition, modeling on worm propagation in smartphones is particularly challenging because it is difficult to piece together dynamics from pair-wise device interactions. To characterize the propagation dynamics of worms in smartphones, we propose an efficient worm propagation modeling scheme using a two-dimensional cellular automata based on the epidemic theory. A set of suitable local transition rules is designed for the two-dimensional cellular automata in this scheme. Moreover, this scheme integrates an infection factor to evaluate the spread degree of infected nodes, and a resistance factor to evaluate the degree that susceptible nodes resist. Five classes of epidemic states are considered: susceptible, exposed, infected, diagnosed, and recovered. We explore a strategy for simulating the dynamics of worm propagation process from a single node to the entire network. The effectiveness and rationality of the proposed model have been validated through extensive simulations. © 2012 Elsevier Inc.

Zhejiang Hisun Pharmaceutical Co. and Central South University | Date: 2010-07-21

The present invention relates to compounds represented by formula (I) or composition comprising at least one of such compounds, which are inhibitors of histone deacetylase. The detailed description of these compounds is disclosed in the Description. These compounds and the composition comprising the same may be useful as medicaments for the treatment of proliferative disorders as well as other diseases involving, relating to or associated with enzymes having histone deacetylase (HDAC) activities.

Qian Zhao Y.,Central South University | Hong Wang X.,Central South University | Fang Wang X.,École Centrale Lyon | Shih F.Y.,New Jersey Institute of Technology
Pattern Recognition | Year: 2014

Retinal vessels play an important role in the diagnostic procedure of retinopathy. Accurate segmentation of retinal vessels is crucial for pathological analysis. In this paper, we propose a new retinal vessel segmentation method based on level set and region growing. Firstly, a retinal vessel image is preprocessed by the contrast-limited adaptive histogram equalization and a 2D Gabor wavelet to enhance the vessels. Then, an anisotropic diffusion filter is used to smooth the image and preserve vessel boundaries. Finally, the region growing method and a region-based active contour model with level set implementation are applied to extract retinal vessels, and their results are combined to achieve the final segmentation. Comparisons are conducted on the publicly available DRIVE and STARE databases using three different measurements. Experimental results show that the proposed method reaches an average accuracy of 94.77% on the DRIVE database and 95.09% on the STARE database. © 2014 Elsevier Ltd. All rights reserved.

Tao S.,Central South University | Yu W.,Shenzhen University
Optics Express | Year: 2015

We present a beam shaping technique in controlling the complex amplitude of an optical beam. The constraint on the amplitude of the output beam in the Gerchberg-Saxton algorithm is replaced with constraints both on the amplitude and phase of the output beam in the proposed method. The total areas of the constrained regions and free regions on the complex amplitude of the output beam in the proposed method are maintained. An output beam with arbitrary complex amplitude can be realized with the proposed method. The computing result from the proposed method is a phase-only distribution, which can be fabricated as diffractive optical element for higher diffraction efficiency. Both simulations and experiments are present and the effectiveness of the proposed method is verified. ©2015 Optical Society of America.

Hu G.,Central South University | Baker S.P.,Center for Injury Research and Policy
Public Health Reports | Year: 2012

Objective. We sought to explain the recent increase in the death rate from falls among Americans aged 65 years and older. Methods. Using the CDC WONDER online database, a longitudinal analysis of subgroups of fall mortality based on the International Classification of Diseases, 10th Revision (ICD-10) was conducted in older adults and in younger people. We used linear regression to examine the statistical significance of trends in mortality rates during 1999-2007. Results. The overall mortality rate from falls increased by 55% among older Americans (≥65 years of age) during 1999-2007, from 29 per 100,000 population to 45 per 100,000 population. For those aged ≥65 years, the largest increase by far (698%) occurred in the subgroup "other falls on the same level," followed by a moderate increase in falls involving wheelchairs or furniture (48%). The steepest increases at all ages occurred from 1999 to 2000, after ICD-10 took effect. State-level analysis confirmed the findings for the entire United States. From 1999 to 2007, total mortality from falls decreased by 5% in people younger than 45 years of age and increased by 44% for those aged 45-64 years; mortality from "other falls on the same level" increased by 202% and 431%, respectively, in these age groups. Conclusions. Because the reported minor increases in emergency department and hospitalization rates for falls were insignificant, the almost sevenfold increase in death rates from "other falls on the same level" strongly suggests an effect of improved reporting quality. © 2012 Association of Schools of Public Health.

Gan M.,Hefei University of Technology | Gan M.,Central South University | Peng H.,Central South University | Chen L.,Central South University
Information Sciences | Year: 2012

We present a hybrid global-local optimization algorithm for parameter estimation of radial basis function (RBF) networks and the RBF-type autoregressive models without exogenous inputs (RBF-AR) or with exogenous inputs (RBF-ARX). The RBF-AR (X) models are quasi-linear time-varying AR (X) models with Gaussian RBF network-style coefficients, which have been used to effectively model the nonlinear behavior of various complex systems. However, the identification of these models is a difficult optimization problem because of the large number of local minima. A hybrid approach is proposed in this paper to achieve better optimization results for these RBF-type models. The applied hybrid search strategy (EA-SNPOM) is developed by combining an evolutionary algorithm (EA) with a gradient-based algorithm known as the structured nonlinear parameter optimization method (SNPOM). This strategy makes use of the robustness of the EA to cover an entire global search space and the efficiency of the gradient search to converge to a local optimum. Several examples of time series modeling and system identification are presented. The simulation results indicate that the performance of the proposed hybrid approach is better than the performance obtained from using each method (EA or SNPOM) alone. Furthermore, the RBF-AR (X) models estimated by the EA-SNPOM achieve much better modeling accuracy relative to other neural networks or fuzzy models in the simulations. © 2012 Elsevier Inc. All rights reserved.

He W.-Y.,Central South University | Ren W.-X.,Central South University | Ren W.-X.,Hefei University of Technology
Finite Elements in Analysis and Design | Year: 2012

Taking advantages of trigonometric Hermite wavelet that has both good approximation characteristics of trigonometric function and multi-resolution, local characteristics of wavelet as interpolating function, the trigonometric wavelet finite beam element is formulated in the paper to carry out the bending, free vibration and buckling of beam structures. Due to the Hermite interpolation properties of trigonometric wavelet, the proposed trigonometric wavelet finite beam element formulation can deal with the boundary conditions and connection between adjacent elements as the traditional finite element method does. Several numerical examples on the bending, free vibration and buckling analysis of beam structures have demonstrated that the trigonometric wavelet finite element method can achieve a good accuracy with less element adopted, especially for free vibration analysis. © 2011 Elsevier B.V. All rights reserved.

Wu Y.,Central South University | Pan X.,National University of Defense Technology
IEEE Transactions on Aerospace and Electronic Systems | Year: 2013

The in-flight alignment is a critical stage for airborne inertial navigation system/Global Positioning System (INS/GPS) applications. The alignment task is usually carried out by the Kalman filtering technique that necessitates a good initial attitude to obtain a satisfying performance. Due to the airborne dynamics, the in-flight alignment is much more difficult than the alignment on the ground. An optimization-based coarse alignment approach that uses GPS position/velocity as input, founded on the newly-derived velocity/position integration formulae is proposed. Simulation and flight test results show that, with the GPS lever arm well handled, it is potentially able to yield the initial heading up to 1 deg accuracy in 10 s. It can serve as a nice coarse in-flight alignment without any prior attitude information for the subsequent fine Kalman alignment. The approach can also be applied to other applications that require aligning the INS on the run. © 1965-2011 IEEE.

Wu Y.,Central South University | Pan X.,National University of Defense Technology
IEEE Transactions on Aerospace and Electronic Systems | Year: 2013

Inertial navigation applications are usually referenced to a rotating frame. Consideration of the navigation reference frame rotation in the inertial navigation algorithm design is an important but so far less seriously treated issue, especially for super high-speed flying vehicles or the future ultraprecision navigation system of several meters per hour. A rigorous approach is proposed to tackle the issue of navigation frame rotation in velocity/position computation by use of the newly-devised velocity/position integration formulae in the Part I companion paper. The two integration formulae set a well-founded cornerstone for the velocity/position algorithms' design that makes the comprehension of the inertial navigation computation principle more accessible to practitioners, and different approximations to the integrals involved give birth to various velocity/position update algorithms. Two-sample velocity and position algorithms are derived to exemplify the design process. In the context of level-flight airplane examples, the derived algorithm is analytically and numerically compared with the typical algorithms that exist in the literature. The results throw light on the problems in existing algorithms and the potential benefits of the derived algorithm. © 1965-2011 IEEE.

Gan M.,Central South University | Gan M.,Hefei University of Technology | Peng H.,Central South University
Applied Soft Computing Journal | Year: 2012

Varying-coefficient models have attracted great attention in nonlinear time series analysis recently. In this paper, we consider a semi-parametric functional-coefficient autoregressive model, called the radial basis function network-based state-dependent autoregressive (RBF-AR) model. The stability conditions and existing conditions of limit cycle of the RBF-AR model are discussed. An efficient structured parameter estimation method and the modified multi-fold cross-validation criterion are applied to identify the RBF-AR model. Application of the RBF-AR model to the famous Canadian lynx data is presented. The forecasting capability of the RBF-AR model is compared to those of other competing time series models, which shows that the RBF-AR model is as good as or better than other models for the postsample forecasts. © 2011 Elsevier B.V. All rights reserved.

Hu G.,Central South University | Baker S.P.,Center for Injury Research and Policy
Injury Prevention | Year: 2010

Objective To identify recent increases in mortality and morbidity rates from injuries among Americans aged 65 years and over. Design A longitudinal analysis of mortality and morbidity data on injuries in the elderly, examining variations in recent trends by cause, sex, race/ethnicity and age group. Setting USA, mortality rate (2000-6) and morbidity rate (2001-7). Data sources Centers for Disease Control and Prevention's web-based injury statistics query and reporting system online database. Main outcome measures Linear regression was used to examine the statistical significance of trends in mortality and morbidity rates in the study period. The percentage change in rates was used to measure the linear trend. Race/ethnicity was classified into Hispanic (all races except black), non-Hispanic white ('white') and black. Results Injury mortality for people aged 65 years and over increased by 3% during 2000-6; morbidity increased by 7% during 2001-7. Falls mortality increased by 42% but emergency department visits for falls did not increase. Significant increases in death rates occurred in motorcycle crashes (145%), machinery (46%), poisoning (34%) and drowning (19%); morbidity rates increased in poisoning (143%), motorcycle crashes (86%), machinery (48%), bicycles (24%), struck by/against (13%) and overexertion (11%). Motor vehicle occupant injuries decreased. Conclusions The reported rate of fatal falls for people aged 65 years and over increased by 42% during 2000-6 but non-fatal falls did not increase. Research is needed to explain the inconsistent changes between fatal and non-fatal falls, and to identify risk factors contributing to the significant increases in both fatal and non-fatal injuries from machinery, motorcycle crashes and unintentional poisoning.

Luo W.,Dalhousie University | Luo W.,Central South University | Li X.,Central South University | Dahn J.R.,Dalhousie University
Chemistry of Materials | Year: 2010

LiNi1/3Mn1/3Co1/3-z(MnMg) z/2O2 (0 ≤ z ≤ 1/3) samples were prepared from hydroxide precursors. The hydroxide precursors were heated with Li 2CO3 at 900 °C for 3 h to prepare the oxides. The XRD results show single phase LiNi1/3Mn1/3Co 1/3-z(MnMg)z/2O2 samples can be prepared for 0 ≤ z ≤ 1/3. Rietveld refinements of XRD data show that when Mn and Mg substitute for Co in NMC there is an increase in the amount of transition metal in the Li layer. Electrochemical studies of the LiNi1/3Mn 1/3Co1/3-z(MnMg)z/2O2 (0≤ z ≤ 1/3) samples were used to measure the rate of capacity reduction with z, found to be about -250 (mAh/g)/(z = 1) charging to 4.3 V and -150 (mA h/g)/(z = 1) charging to 4.6 V. The impact of Mn and Mg cosubstitution on the thermal stability of charged LiNi1/3Mn1/3Co1/3-z(MnMg) z/2O2 (0 ≤ z ≤ 1/3) samples in electrolyte was studied using accelerating rate calorimetry. The thermal stability of LiNi 1/3Mn1/3Co1/3-z(MnMg)z/2O 2 is independent of z for the samples studied. © 2010 American Chemical Society.

Sun L.,Central South University | Kanwar Y.S.,Northwestern University
Kidney International | Year: 2015

An ancillary paradigm that has evolved recently in the pathogenesis of diabetic nephropathy includes subclinical microinflammation with influx of macrophages and consequent generation of myriad proinflammatory cytokines and ensuing kidney damage. Among various proinflammatory cytokines, tumor necrosis factor-α (TNF-α) has attracted the most attention, since it amplifies the inflammatory network of cytokines, leading to worsening of the progression of diabetic nephropathy. The article by Awad et al. examines the role of TNF-α in the pathogenesis of experimental diabetic nephropathy.

Kanwar Y.S.,Northwestern University | Sun L.,Northwestern University | Xie P.,Northwestern University | Liu F.-Y.,Central South University | Chen S.,Northwestern University
Annual Review of Pathology: Mechanisms of Disease | Year: 2011

Diabetic nephropathy is a well-known complication of diabetes and is a leading cause of chronic renal failure in the Western world. It is characterized by the accumulation of extracellular matrix in the glomerular and tubulointerstitial compartments and by the thickening and hyalinization of intrarenal vasculature. The various cellular events and signaling pathways activated during diabetic nephropathy may be similar in different cell types. Such cellular events include excessive channeling of glucose intermediaries into various metabolic pathways with generation of advanced glycation products, activation of protein kinase C, increased expression of transforming growth factor β? and GTP-binding proteins, and generation of reactive oxygen species. In addition to these metabolic and biochemical derangements, changes in the intraglomerular hemodynamics, modulated in part by local activation of the renin-angiotensin system, compound the hyperglycemia-induced injury. Events involving various intersecting pathways occur in most cell types of the kidney. Copyright © 2011 by Annual Reviews. All rights reserved.

Jiang S.,Michigan State University | Cao D.,Michigan State University | Li Y.,University of Sichuan | Liu J.,Central South University | Peng F.Z.,Michigan State University
IEEE Transactions on Power Electronics | Year: 2012

This paper presents a novel synchronous-frame repetitive controller for three-phase UPS inverters. Distinguished from conventional repetitive control techniques, the proposed synchronous-frame approach minimizes the repetitive control time delay to one-sixth of the fundamental period such that the dynamic response is significantly improved. In order to overcome the harmonic distortions under severe load conditions (e.g., unbalanced and nonlinear), in this paper, three synchronous rotating frames are deliberately selected, in each of which the repetitive controller is incorporated. Resultantly, the (6n ± 1)th harmonics as well as the triplen harmonics are compensated. Moreover, a high-performance fourth-order linear phase infinite-impulse-response filter is applied to further enhance the accuracy of steady-state tracking. The proposed controller is programmed on the 16-bit fixed-point digital signal processor (TI TMS320LF2407) and eliminates high-resolution current sensors for cost effectiveness. Simulations and experimental tests have been carried out based on an 18-kW three-phase UPS system. Low total harmonic distortion (<2) has been achieved under heavily distorted nonlinear load and unbalanced load. Fast dynamic response has been demonstrated during step load transients. © 2006 IEEE.

Tiruveedhula M.,University of Southampton | Reading I.C.,Central South University | Clarke N.M.P.,University of Southampton
Journal of Pediatric Orthopaedics | Year: 2015

BACKGROUND:: Avascular necrosis (AVN) of the femoral head is an irreversible complication seen in the treatment of developmental dysplasia of hip (DDH) with the Pavlik harness. Its incidence is reported to be low after successful reduction of the hip but high if the hip is not concentrically relocated. We aim to investigate its incidence after failed Pavlik harness treatment. METHODS:: We prospectively followed up a group of children who failed Pavlik harness treatment for DDH treated at our institution by the senior author between 1988 and 2001 and compared their rates of AVN with a group of children who presented late and hence were treated surgically. AVN was graded as described by Kalamchi and MacEwen and only grade 2 to 4 AVN was considered significant and included in the analysis. RESULTS:: Thirty-seven hips were included in the failed Pavlik group (group 1) and 86 hips in the no Pavlik group (group 2). Ten hips in group 1 developed AVN (27%), whereas only 7 hips in group 2 (8%) developed AVN; the odds of developing AVN after failed Pavlik treatment was 4.7 (95% confidence interval, 1.3-14.1) (P=0.009) with a relative risk of 3.32 (range, 1.37 to 8.05). CONCLUSIONS:: There was no statistically significant association observed with duration of splintage and severity of AVN (Spearman's correlation, -0.46; P=0.18). However, there was a positive correlation noted with age at presentation and severity of AVN. Therefore, we advise close monitoring of hips in the Pavlik harness and discontinue its use if the hips are not reduced within 3 weeks. LEVEL OF EVIDENCE:: Level III.

Edens B.M.,Northwestern University | Ajroud-Driss S.,Northwestern University | Ma L.,Central South University | Ma Y.-C.,Northwestern University
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2015

Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, is characterized by the degeneration of spinal motor neurons and muscle atrophy. Although the genetic cause of SMA has been mapped to the Survival Motor Neuron1 (SMN1) gene, mechanisms underlying selective motor neuron degeneration in SMA remain largely unknown. Here we review the latest developments and our current understanding of the molecular mechanisms underlying SMA pathogenesis, focusing on the animal model systems that have been developed, as well as new diagnostic and treatment strategies that have been identified using these model systems. This article is part of a special issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis. © 2014 Elsevier B.V.

Huang H.,Guilin University of Technology | Huang K.,Central South University
Powder Technology | Year: 2012

The La-Mg-Ni based composites Mm 0.80Mg 0.20Ni 2.56Co 0.50Mn 0.14Al 0.12- xwt.% AB 5 (x=0, 10, 20, 30) alloys were successfully synthesized by ball milling method. The structure and electrochemical characteristics of composites have been investigated systematically. The XRD spectroscopy shows that all these composites are mainly composed of La 2Ni 7 phase and LaNi 5 phase. The electrochemical studies suggest that the maximum discharge capacity (C max) of alloy electrodes decreases slightly from 361.8 mAh/g (x=0) to 337.9 mAh/g (x=10), 353.9 mAh/g (x=20) and 352.8 mAh/g (x=30), while the cycle durability of the composite electrodes is significantly improved. Moreover, the electrochemical kinetic measurements indicate that the x=20 composite alloy electrode presents the best overall electrochemical properties. © 2012 Elsevier B.V.

Zhang S.-L.,Linzi District Peoples Hospital | Liu L.,Central South University
Experimental and Therapeutic Medicine | Year: 2015

microRNA (miR)-148a has been shown to act as an important suppressor in numerous human malignancies and is markedly downregulated in hepatocellular carcinoma; however, the role of miR-148a in the regulation of hepatocellular carcinoma cell invasion, as well as the underlying mechanism, has never been studied. In the present study, the expression level of miR-148a was found to be significantly decreased in hepatocellular carcinoma tissues and HepG2 cells when compared with that in the normal adjacent tissues. Furthermore, a novel target of miR-148a was found, sphingosine-1-phosphate receptor 1 (S1PR1), whose expression was negatively regulated by miR-148a at a post-transcriptional level in hepatocellular carcinoma HepG2 cells. Upregulation of miR-148a by transfection with miR-148a mimics notably suppressed HepG2 cell invasion, similar to the effect of the SIPR1 downregulation induced by SIPR1-specific small interfering RNA, while the restoration of S1PR1 expression reversed the inhibitory effect of miR-148a upregulation on HepG2 cell invasion. Accordingly, the current study suggests that miR-148a plays an inhibitory role in the regulation of hepatocellular carcinoma cell invasion by directly targeting S1PR1. © 2014, Spandidos Publications. All rights reserved.

Peng X.-L.,Changsha University of Science and Technology | Li X.-F.,Central South University
International Journal of Mechanical Sciences | Year: 2012

This paper investigates an elastic problem of rotating functionally graded hollow polar orthotropic circular disks. Emphasis is placed on the influence of orthotropy and gradient on the elastic field in particular the hoop stress distribution in hollow annular plates rotating at constant angular speed about its axis. For the gradient of power-law profile, we obtain explicit expressions for the elastic field. For arbitrarily variable gradient, we present a method for transforming the problem into solving a Fredholm integral equation. Numerical results are presented for two particular cases: free boundaries and clamped-free boundaries. A comparison of numerical results with exact ones for power-law material properties is made, indicating the effectiveness of our proposed method. For material properties varying in any way according to the Voigt rule, numerical results are presented to show the effects of gradient parameter and orthotropy degree on the distribution of elastic field. © 2012 Elsevier Ltd.

Huang Y.-S.,Changsha University of Science and Technology | Huang Y.-S.,Central South University
International Journal of Robust and Nonlinear Control | Year: 2012

In this paper, a novel decentralized robust adaptive fuzzy control scheme is proposed for a class of large-scale multiple-input multiple-output uncertain nonlinear systems. By virtue of fuzzy logic systems and the regularized inverse matrix, the decentralized robust indirect adaptive fuzzy controller is developed such that the controller singularity problem is addressed under a united design framework; no a priori knowledge of the bounds on lumped uncertainties are being required. The closed-loop large-scale system is proved to be asymptotically stable. Simulation results confirmed the validity of the approach presented. Copyright © 2011 John Wiley & Sons, Ltd.

Han K.,Central South University | Liu Z.,Northwestern University | Ye H.,Central South University | Dai F.,Optimal CAE Inc.
Journal of Power Sources | Year: 2014

A flexible, self-standing graphene-Se@CNT composite film has been synthesized by a facile two-step assembly process. The film is directly employed as cathode for rechargeable Li-Se batteries without extra binders and conductive additives. It exhibits much higher reversible capacity and cycling stability (315 mAh g-1 after 100 cycles at 0.1 C) than graphene-Se composite film. The improved electrochemical performance is mainly attributed to the synergistic effects of graphene and CNT, which not only function as a flexible scaffold for strains/stresses release and volume expansion, but also offer a three-dimensional conductive architecture with open channels for electron transfer and Li ion diffusion, as well as strong confinement of soluble polyselenides. © 2014 Elsevier B.V. All rights reserved.

Zhang B.,Central South University | Li L.,Changsha University of Science and Technology | Zheng J.,Central South University
Journal of Alloys and Compounds | Year: 2012

Cr and Mg co-substituted LiNi 0.8Co 0.1Mn 0.1O 2 samples are synthesized by fast co-precipitation method and characterized by scanning electron microscope, X-ray diffraction, Rietveld refinement and electrochemical measurements. The Rietveld refinement results show that suitable Cr and Mg co-substitution could lead to synergistic reaction to form a kind of complementary structure, by full Cr occupying in Ni layer, and full Mg occupying in Li layer, respectively, and further attribute to highly ordered layered LiNi 0.8Co 0.1Mn 0.1O 2 with low cation mixing degree. Electrochemical studies demonstrate that Cr and Mg co-substitution in LiNi 0.8Co 0.1Mn 0.1O 2 also result in improved discharge capacity, initial coulombic efficiency, rate ability and cycling property compared to pristine LiNi 0.8Co 0.1Mn 0.1O 2. The improvements of electrochemical property resulted from the stabilized host structure by Cr and Mg incorporation into LiNi 0.8Co 0.1Mn 0.1O 2. © 2011 Elsevier B.V. All rights reserved.

Xu X.,University of Science and Technology Beijing | Li L.,University of Science and Technology Beijing | Liu B.,Central South University | Zou Y.,Central South University
Applied Physics Letters | Year: 2011

Polyfluorene and its derivatives are good candidates to fabricate single-component polymer memories. However, the reported polyfluorenes for use in memories all have a big band gap and exhibit an absorption peak near the ultraviolet region. We report here organic memories based on a low-band gap polyfluorene derivative with isoindigo as electron-trapping moieties to improve on/off ratios. Also, possible factors which may influence the performance of polymer memory devices are investigated and feasible approaches for improving device performance are provided. © 2011 American Institute of Physics.

Huang Y.-S.,Central South University | Huang Y.-S.,Changsha University of Science and Technology | Wu M.,Central South University
Information Sciences | Year: 2011

In the previous work of Huang et al., a decentralized direct adaptive fuzzy H ∞ tracking controller of large-scale nonaffine nonlinear systems is obtained predicated upon the assumption that the mismatching error dynamics stay squared integrable. In this note, we focus in the absence of the conservative assumption upon developing a robust decentralized direct adaptive output feedback fuzzy controller. By combination of a state observer, a fuzzy inference system and robust control technique, the previous controller design is modified and no a priori knowledge of bounds on lumped uncertainties is required. All the signals of the closed-loop large-scale system are proved to be uniformly ultimately bounded. The effectiveness of the developed scheme is demonstrated through the simulation results of interconnected inverted pendulums. © 2010 Elsevier Inc. All rights reserved.

Jin X.-F.,Beijing Institute of Pharmacology and Toxicology | Jin X.-F.,Central South University | Wu N.,Beijing Institute of Pharmacology and Toxicology | Wang L.,Beijing Institute of Pharmacology and Toxicology | Li J.,Beijing Institute of Pharmacology and Toxicology
Cellular and Molecular Neurobiology | Year: 2013

As a class of important endogenous small noncoding RNAs that regulate gene expression at the posttranscriptional level, microRNAs (miRNAs) play a critical role in many physiological and pathological processes. It is believed that miRNAs contribute to the development, differentiation, and synaptic plasticity of the neurons, and their dysregulation has been linked to a series of diseases. MiRNAs exist in the tissues and as circulating miRNAs in several body fluids, including plasma or serum, cerebrospinal fluid, urine, and saliva. There are significant differences between the circulating miRNA expression profiles of healthy individuals and those of patients. Consequently, circulating miRNAs are likely to become a novel class of noninvasive and sensitive biomarkers. Although little is known about the origin and functions of circulating miRNAs at present, their roles in the clinical diagnosis and prognosis of diseases make them attractive markers, particularly for tumors and cardiovascular diseases. Until now, however, there have been limited data regarding the roles of circulating miRNAs in central nervous system (CNS) diseases. This review focuses on the characteristics of circulating miRNAs and their values as potential biomarkers in CNS diseases, particularly in Alzheimer's disease, Huntington's disease, multiple sclerosis, schizophrenia, and bipolar disorder. © 2013 Springer Science+Business Media New York.

Wang Y.,Central South University | Wang D.,Central South University | Yan J.,Hunan University of Science and Technology
Journal of Alloys and Compounds | Year: 2014

Multilayer MoSi2/MoB coating was formed by in situ chemical vapour deposition on Mo substrate. Following oxidation exposure, the continuous MoSi2 phase layer is observed in the MoSi2/MoB coating. But the MoSi2 phase layer transformed into Mo5Si 3 and Mo3Si phases in the single MoSi2 coated Mo. The MoSi2/MoB composite coating provided an excellent oxidation resistance and has a longer service lifetime than single MoSi2 coating. © 2013 Elsevier B.V. All rights reserved.

Li X.-F.,Central South University | Xi L.-Y.,Central South University | Huang Y.,Foshan University
Composites Part B: Engineering | Year: 2011

The stability analysis of a vertically standing or hanging composite column under end force and distributed axial load is made. The composite column has varying cross-section and variable material properties. The integral equation method is formulated to deal with this problem. Critical buckling load can be evaluated by seeking the lowest eigenvalue of the resulting integral equation. A characteristic equation is derived and it is a polynomial equation. The effects of self-weight and taper ratio on the buckling load are discussed for clamped-free prismatic and non-prismatic columns. As an application, two optimum design problems of freestanding tapered columns against buckling are considered to enhance the load-carrying capacity of cantilevered non-uniform columns. One is devoted to the parameter optimization of given shape profile for a homogeneous heavy column subjected to gravity load and tip load simultaneously under constant weight or volume constraint, and obtained results are very close to the exact ones of the strongest columns; the other is devoted to material tailoring such that the ratio of buckling load to weight reaches maximum for an axially graded inhomogeneous column made of two constituents with uniform cross-section. © 2011 Elsevier Ltd. All rights reserved.

Huang Y.,Foshan University | Luo Q.-Z.,Foshan University | Li X.-F.,Central South University
Composite Structures | Year: 2013

This paper studies the behavior of flexural waves traveling in carbon nanotubes (CNTs) in a free space and embedded in an elastic matrix. An exact higher-order model for analyzing dynamic behavior of nonlocal elastic beams with circular cross-section is proposed, where shear deformation and rotary inertia are both considered without introducing the shear correction factor. Moreover, traction-free condition at the beam surface is met. Using this model, wave dispersion of CNTs is studied and dispersion relation is obtained for single-walled and double-walled CNTs, respectively. Scale-dependent wave speed is given. The effectiveness and validity of the method are confirmed by comparing obtained numerical results with those based on molecular dynamics simulation, the nonlocal Euler-Bernoulli beam theory and nonlocal Timoshenko beam theory with stress gradient and strain gradient. The effects of the scale coefficient, the surrounding elastic medium and van der Waals force on the phase velocity are expounded. © 2012 Elsevier Ltd.

Wang S.-E.,Central South University | Wang S.-E.,Guangxi Normal University | Si S.,Central South University
Analytical Methods | Year: 2013

Coupling nanomaterials with biomolecular recognition events represents a new direction in nanotechnology toward the development of novel molecular diagnostic tools. A novel aptamer biosensor based on multi-walled carbon nanotube (MWCNT) long-range energy transfer has been developed for sensitive, selective and multicolor fluorescent detection of Hg2+, Ag + and Pb2+ ions in homogeneous solution. The fluorescent dye-labeled aptamer is adsorbed on MWCNTs due to their strong π-π stacking interactions, leading to quenching of fluorescence of the dye. Desorption of the dye-labeled aptamer from MWCNTs, through the specific binding of the aptamer with its target, resulted in the restoration of the fluorescence signal of the dye. Due to the non-covalent assembly between the aptamer and MWCNTs, highly efficient long-range energy transfer from the dyes to MWCNTs takes place. In the presence of metal ions, the binding between the aptamer and metal ions will disturb the interaction between the aptamer and MWCNTs, and release the dye-labeled aptamer from the MWCNTs' surface, resulting in restoration of the fluorophore's fluorescence. Importantly, the high specific surface area of MWCNTs allows the quenching of multiple aptamer probes labeled with different fluorescent dyes, leading to a multicolor nanosensor for simultaneous detection of multiple metal ions in the same solution. As a proof of concept, we demonstrated that a three-color nanosensor can rapidly and simultaneously detect three metal ions (i.e. Hg2+, Ag+ and Pb2+) in a single solution. This MWCNT-based sensing platform exhibits high sensitivity and selectivity toward Hg2+, Ag+ and Pb2+versus other metal ions, with a limit of detection of 15 nM for Hg2+, 18 nM for Ag+ and 20 nM for Pb2+. This journal is © The Royal Society of Chemistry.

Zhang Q.C.,Howard Hughes Medical Institute | Petrey D.,Howard Hughes Medical Institute | Garzon J.I.,Howard Hughes Medical Institute | Deng L.,Howard Hughes Medical Institute | And 2 more authors.
Nucleic Acids Research | Year: 2013

PrePPI ( is a database that combines predicted and experimentally determined protein-protein interactions (PPIs) using a Bayesian framework. Predicted interactions are assigned probabilities of being correct, which are derived from calculated likelihood ratios (LRs) by combining structural, functional, evolutionary and expression information, with the most important contribution coming from structure. Experimentally determined interactions are compiled from a set of public databases that manually collect PPIs from the literature and are also assigned LRs. A final probability is then assigned to every interaction by combining the LRs for both predicted and experimentally determined interactions. The current version of PrePPI contains ∼2 million PPIs that have a probability more than 0.1 of which ∼60000 PPIs for yeast and ∼370000 PPIs for human are considered high confidence (probability > 0.5). The PrePPI database constitutes an integrated resource that enables users to examine aggregate information on PPIs, including both known and potentially novel interactions, and that provides structural models for many of the PPIs. © The Author(s) 2012.

Huang Y.,Guangxi Normal University | Huang Y.,Central South University | Zhao S.,Guangxi Normal University | Chen Z.-F.,Guangxi Normal University | And 2 more authors.
Chemical Communications | Year: 2012

We have developed an amplified fluorescence polarization aptasensor that relies on aptamer structure-switching-triggered nanoparticles (NPs) enhancement for biomolecules detection. This new type of assay exhibits higher detection sensitivity over traditional homogeneous aptasensors by two orders of magnitude and high specificity for target molecules. © 2012 The Royal Society of Chemistry.

de la Cruz I.P.,Howard Hughes Medical Institute | Ma L.,Central South University | Horvitz H.R.,Howard Hughes Medical Institute
PLoS Genetics | Year: 2014

Loss-of-function mutations in the Caenorhabditis elegans gene sup-18 suppress the defects in muscle contraction conferred by a gain-of-function mutation in SUP-10, a presumptive regulatory subunit of the SUP-9 two-pore domain K+ channel associated with muscle membranes. We cloned sup-18 and found that it encodes the C. elegans ortholog of mammalian iodotyrosine deiodinase (IYD), an NADH oxidase/flavin reductase that functions in iodine recycling and is important for the biosynthesis of thyroid hormones that regulate metabolism. The FMN-binding site of mammalian IYD is conserved in SUP-18, which appears to require catalytic activity to function. Genetic analyses suggest that SUP-10 can function with SUP-18 to activate SUP-9 through a pathway that is independent of the presumptive SUP-9 regulatory subunit UNC-93. We identified a novel evolutionarily conserved serine-cysteine-rich region in the C-terminal cytoplasmic domain of SUP-9 required for its specific activation by SUP-10 and SUP-18 but not by UNC-93. Since two-pore domain K+ channels regulate the resting membrane potentials of numerous cell types, we suggest that the SUP-18 IYD regulates the activity of the SUP-9 channel using NADH as a coenzyme and thus couples the metabolic state of muscle cells to muscle membrane excitability. © 2014 de la Cruz et al.

Wang H.-Q.,Guangxi Normal University | Li Z.-S.,Guangxi Normal University | Huang Y.-G.,Guangxi Normal University | Li Q.-Y.,Guangxi Normal University | Wang X.-Y.,Central South University
Journal of Materials Chemistry | Year: 2010

A novel non-aqueous hybrid supercapacitor was fabricated from two spherical materials - an activated mesocarbon microbead (AMCMB) and MnO2 nanowire-sphere, as the negative and positive electrodes, respectively. The preliminary results for this energy-storage device, which operates over a wide voltage range (0.0-3.0 V) using 1 M Et4NBF4 in acetonitrile (AN) as electrolytes, are presented. On the basis of a single electrode, the AMCMBMnO2 supercapacitor displays a high specific capacitance of 228 F g-1 at a scan rate of 10 mV s-1, corresponding to specific energy of 128 W h kg-1 based on based on the total mass of active materials, while maintaining desirable cycling stability and rate capability. The combination of the spherical AMCMB and MnO2 in a non-aqueous electrolyte is proved to be suitable for high-performance hybrid supercapacitor applications. © 2010 The Royal Society of Chemistry.

Xia X.,Central South University | Xia X.,Hunan University of Science and Technology | Long Y.,Hunan University of Science and Technology | Wang J.,Central South University
Analytica Chimica Acta | Year: 2013

Creation and application of noble metal nanoclusters have received continuous attention. By integrating enzyme activity and fluorescence for potential applications, enzyme-capped metal clusters are more desirable. This work demonstrated a glucose oxidase (an enzyme for glucose)-functionalized gold cluster as probe for glucose. Under physiological conditions, such bioconjugate was successfully prepared by an etching reaction, where tetrakis (hydroxylmethyl) phosphonium-protected gold nanoparticle and thioctic acid-modified glucose oxidase were used as precursor and etchant, respectively. These bioconjugates showed unique fluorescence spectra (λem max=650nm, λex max=507nm) with an acceptable quantum yield (ca. 7%). Moreover, the conjugated glucose oxidase remained active and catalyzed reaction of glucose and dissolved O2 to produce H2O2, which quenched quantitatively the fluorescence of gold clusters and laid a foundation of glucose detection. A linear range of 2.0×10-6-140×10-6M and a detection limit of 0.7×10-6M (S/N=3) were obtained. Also, another horseradish peroxidase/gold cluster bioconjugate was produced by such general synthesis method. Such enzyme/metal cluster bioconjugates represented a promising class of biosensors for biologically important targets in organelles or cells. © 2013.

Central South University and Hunan Boyun Automobile Brake Materials Co. | Date: 2010-12-30

An automotive ceramic friction material free from asbestos and metal and preparation method thereof are provided. The material includes the following components: organic adhesive, reinforced fiber, friction-increasing agent, antifriction agent and fillers. The material has high coefficient of friction, stable braking performance, low heat fading, low wear resistance and long service life.

Wan N.,University of Nebraska Medical Center | Zou B.,Central South University | Sternberg T.,University of Oxford
International Journal of Geographical Information Science | Year: 2012

Gravity-based spatial access models have been widely used to estimate spatial access to healthcare services in an attempt to capture the interaction of various factors. However, these models are inadequate in informing health resource allocation work due to their inappropriate assumption of healthcare demand. For the purpose of effective healthcare resource planning, this article proposes a three-step floating catchment area (3SFCA) method to minimize the healthcare-demand overestimation problem. Specifically, a spatial impedance-based competition scheme is incorporated into the enhanced two-step floating catchment area (E2SFCA) method to account for a reasonable model of healthcare supply and demand. A case study of spatial access to primary care physicians along the Austin-San Antonio corridor area in central Texas showed that the proposed method effectively minimizes the overestimation of healthcare demand and reflects a more balanced geographic pattern of spatial access than E2SFCA. In addition, by using an adjusted spatial access index, the 3SFCA method indicates strong potential for identifying health professional shortage areas. The study concludes that 3SFCA is a promising method to provide health professionals and decision makers with useful healthcare accessibility information. © 2012 Taylor & Francis.

Li Q.,Central South University | Zhu F.,Central South University | Chen P.,Central South University
Biochemical and Biophysical Research Communications | Year: 2012

Many microRNAs have been implicated as key regulators of cellular growth and differentiation and have been found to dysregulate proliferation in human tumors, including breast cancer. Cancer-linked microRNAs also alter the epigenetic landscape by way of DNA methylation and post-translational modifications of histones. Aberrations in Hox gene expression are important for oncogene or tumor suppressor during abnormal development and malignancy. Although recent studies suggest that HoxB3 is critical in breast cancer, the putative role(s) of microRNAs impinging on HoxB3 is not yet fully understood. In this study, we found that the expression levels of miR-7 and miR-218 were strongly and reversely associated with HoxB3 expression. Stable overexpression of miR-7 and miR-218 was accompanied by reactivation of tumor suppressor genes including RASSF1A and Claudin-6 by means of epigenetic switches in DNA methylation and histone modification, giving rise to inhibition of the cell cycle and clone formation of breast cancer cells. The current study provides a novel link between overexpression of collinear Hox genes and multiple microRNAs in human breast malignancy. © 2012 Elsevier Inc.

Wang J.,Central South University | Peng X.,Central South University | Peng W.,Central South University | Wu F.-X.,University of Saskatchewan
Proteomics | Year: 2014

With more dynamic information available, researchers' attention has recently shifted from static properties to dynamic properties of protein-protein interaction networks. To compensate the limited ability of technologies of detecting dynamic protein-protein interactions, dynamic protein interaction networks (DPINs) can be constructed by involving proteomic, genomic, and transcriptome analyses. Two groups of DPIN construction methods are classified based on the different focuses on dynamic information extracted from gene expression data. The dynamics of one kind of DPINs is reflected by the changes in protein presence varying with time, while that of the other kind of DPINs is reflected by the differences of coexpression under different conditions. In this review, the applications on DPINs will be discussed, including protein complexes/functional modules and network organization analysis, biomarkers detection in the progression or prognosis of the disease, and network medicine. We also point out the challenges in DPINs construction and future directions in the research of DPINs at the end of this review. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen L.,Central South University | Liu Y.,Central South University
Journal of Colloid and Interface Science | Year: 2011

Dendritic and porous Ag-Pd alloy nanostructures were successfully fabricated on the surface of silicon substrate using the co-reduction method and galvanic replacement reaction, respectively. The molar compositions of Ag and Pd in the alloy could be modulated by controlling the molar ratios of metal precursors and reaction time. The Ag-Pd alloy nanostructures were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The morphology and phase of Au-Pd alloy nanostructures were discussed as a function of molar ratios of metal precursors and reaction time. In addition, the morphology and composition-dependent surface-enhanced Raman scattering (SERS) of the as-synthesized Ag-Pd alloy nanostructures were investigated. The SERS enhancement factor was estimated and SERS mapping was performed to prove the homogeneity of these substrates. The results indicate that as-synthesized dendritic and porous Ag-Pd alloy nanostructures are good candidates for SERS spectroscopy. © 2011 Elsevier Inc.

Yang M.H.,Central South University
Zhonghua er ke za zhi. Chinese journal of pediatrics | Year: 2010

Multidrug resistance (MDR) is one of the primary causes of suboptimal outcomes in chemotherapy of children with acute myeloblastic leukemia (AML). The mechanisms of drug transport resistance may chiefly contribute to MDR. Expression and/or activity of P-glycoprotein (P-gp), multiple resistance-associated protein-1 (MRP1), lung-resistance related protein (LRP) and breast cancer resistance protein (BCRP) have been considered to be associated with unfavourable outcomes in pediatric AML patients. In previous studies, we found WASP-family verprolin-homologous protein-1 (WAVE1) was involved in the MDR mechanisms in K562/A02 leukemia cells. To investigate the expression of WAVE1, P-gp, MRP1, LRP/MVP and BCRP; and if WAVE1 is involved in MDR of human leukemia cell. WAVE1, P-gp, MRP1, LRP, BCRP mRNA and protein expression in bone marrow mononuclear cells (BMMCs) were measured by real-time fluorescence quantitative PCR (RQ-PCR) and Western blot in a cohort of 52 children with acute myeloblastic leukemia. During follow-up, of the 52 patients, 21 were documented as being relapsing or refractory, and 31 were induced into complete continuous remission. Furthermore, HL60 cells and HL60/ADR cells were transiently transfected with PCDNA3.1-WAVE1 reconstructed plasmid and specifically siRNA to WAVE1 respectively, and the expression of WAVE1, MRP1 and BCRP before and after transfection was assessed by real-time PCR and Western blot analysis. (1) The expression levels of WAVE1, P-gp, MRP, LRP and BCRP in refractory/relapsing group were much higher than that in complete continuous remission (CCR) group. (2) WAVE1 mRNA and protein expression in BMMCs of children were at higher levels when they were newly diagnosed or relapsed, compared with complete continuous remission. (3) The WAVE1 expression at mRNA and protein level in HL60/ADR cells was increased by about 353% and 95% respectively as compared with that in HL60 cells. (4) Overexpression of WAVE1 in HL60 cell lines upregulated the expression levels of MRP and BCRP (MRP mRNA and protein level were increased by about 16.54 times and 129% respectively, BCRP was increased by 4.93 times and 96%); whereas suppression of WAVE1 expression by RNA interference downregulated the expression levels of MRP1 and BCRP (MRP mRNA and protein level was only 11% and 43% of pre-disturbance respectively, BCRP was 14% and 71%). Higher levels of WAVE1 in the BM indicate an unfavorable prognosis in children with AML. WAVE1 is related to the development of AML and involved in the MDR mechanisms, and regulates the level of MRP1 and BCRP.

Chen X.,Central South University | Wang D.,Central South University | Wang Z.,Central South University | Zhou P.,Central South University | And 2 more authors.
Chemical Communications | Year: 2014

Molybdenum phosphide was adopted as a new electrocatalyst for the hydrogen evolution reaction for the first time, exhibiting an excellent electrocatalytic activity with a small Tafel slope of 60 mV dec-1, which is amongst the most active, acid-stable, earth abundant HER electrocatalysts reported to date. This journal is © the Partner Organisations 2014.

A finite element model of fluid field of front-box and 3-spacer nozzle of aluminum roll-casting has been developed to provide a comparison of analyzing distribution of velocity and temperature of outlet of nozzle with variable velocity. The computation is performed by using coupled fluid-thermal FEM simulation of FLOTRAN module in ANSYS 6.0. The boundary conditions of the roll-casting model of fluid and thermal fields, were loaded on front-box and nozzle. Based on the postprocessing function of ANSYS, the strict result analysis was conducted by MATLAB. Results based on the allowable inhomogeneity of velocity and temperature of outlet show the most possible broken regions of outlet could be predicted in the case of speed increasing of the drawing-sheet and thickness reducing of the aluminium sheet. The profile parameters of the nozzle including distribution, shapes and sizes of the nozzle spacers, and shapes of inner nozzle must be optimized to be appropriate in high roll cast speed. © (2010) Trans Tech Publications, Switzerland.

Wu Z.,Central South University | Zhu Y.,Central South University | Ji X.,Central South University
Journal of Materials Chemistry A | Year: 2014

Nickel cobaltite (NiCo2O4), with excellent electrochemical performance, has become a new class of energy storage material for electrochemical supercapacitors, which facilitates to relieve the pressure of energy crisis and environmental pollution. It possesses richer electroactive sites and at least two magnitudes higher electrical conductivity than that of NiO and Co3O4, which exhibit not only large power density, but also high energy density of up to 35 W h kg-1. Furthermore, it shows comparable capacitive performances with noble metal oxides of RuO 2, but with much lower cost and more abundant resources. This feature article briefly analyses the energy storage mechanism of NiCo2O 4, summarizes the methodologies and nanostructures discovered in recent years, and points out the potential problems and future prospects of utilizing NiCo2O4-based materials as supercapacitor electrodes. Moreover, composite electrodes based on nickel cobaltite are also elaborated with considerable interest. Since the pioneering work of Hu and his group in 2010, numerous research studies have also demonstrated NiCo 2O4 electrodes to show remarkable supercapacitive performances; however, more specialized work should be performed to further develop the potential of this novel electrode material so as to realize their massive commercial applications. © the Partner Organisations 2014.

Yang B.,Central South University | Yang Z.,Central South University | Wang R.,Central South University | Feng Z.,Central South University
Journal of Materials Chemistry A | Year: 2014

Simple and facile processes to produce silver nanoparticle deposited layered double hydroxide (Ag-LDH) nanosheets are reported. By a wet chemical reduction method in an aqueous AgNO3 solution, silver ions can be readily reduced to metallic silver nanoparticles and incorporated evenly on the surface of 2D LDH nanosheets. Structure and morphology analysis of the Ag-LDH composites is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Ag-LDH composites are characterized electrochemically proving their exceptional cyclability and high discharge capacity. Electrochemical impedance spectroscopy (EIS) and four-point probe conductivity measurements show that silver modification decreases the charge transfer resistance of the anode, and improves the conductivity of the active material, which boosts the electrochemical performance of Ag-LDH composites. These newly designed Ag-LDH nanosheets may offer a promising anode candidate for high-performance Ni-Zn secondary batteries and other zinc battery applications. © 2014 The Royal Society of Chemistry.

Xu X.-H.,Central South University
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2011

In multi-attribute complex large group-decision, effectively clustering the decision results of decision makers is the base to analyze and complete group decision. Aiming at the disadvantages for parameters selecting's complexity, self-adaptive shortage and their randomicity in ants-clustering algorithm, an improved ants-clustering algorithm is proposed. Several evaluating criterion values of a decision problem from decision makers are converted into preference vectors in the algorithm. The preference vectors' clustered degree is taken as the calculating formula of the neighborhood similarity degree to form a heuristic clustering algorithm. A calculation example is used to show that the algorithm holds the characteristic of high clustering quality, self organization and robustness, which is applicable to solve the problem for multi-attribute complex large group clustering and decision making.

Li Y.,Central South University
Advanced Materials Research | Year: 2011

Due to the limitations of the existing strength theories or criteria, the phenomenon of material failure cannot be not fully explained, which makes material strength criterion to always be an important direction to study. Reference [1] found that there was a certain relationship between elastic strain and plastic strain, and a preliminary summing-up of this relationship had been done. Based on the relationship, the dominant factor of material failure has been analyzed, and a new strength criterion has been established with plastic strain as the control value. The new criterion is of simple expression, and can be used to explain very well some experiment phenomena.

Li X.,Central South University
Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences | Year: 2011

The research team on the National Key Scientific Program of China: "Transcriptomic regulation and molecular mechanism research of polygenic tumor at different stages" has focused on the field of transcriptomics of 4 common polygenic tumors, including nasopharyngeal carcinoma(NPC), breast cancer, colorectal cancer, and glioma. Extensive laboratory work has been carried out on the expression and regulation of tumor transcriptomics; identification of tumor suppressor/susceptible genes; mechanism of tumor epigenetics including miRNAs, and comparative study of specific gene/protein cluster of tumor transcriptomics and proteomics. Genes including SPLUNC1, LTF, BRD7, NOR1, BRCA1/2, PALB2, AF1Q, SOX17, NGX6, SOX7, and LRRC4 have been identified as the key transcriptional regulation genes during the stage of tumor initiation and invasion. Accordingly,the NPC gene signal regulation network of "SPLUNC1-miR-141-target genes", the breast cancer interaction signal pathway of "miR-193b-uPA",the glioma signal network of "miR-381- LRRC4-MEK/ERK/AKT", and the miRNA-target gene network of colorectal cancer metastasis related gene NGX6 have been thoroughly elucidated. These fruitful Results imply that the changes of key molecules in crucial signal pathway will cause severe dysfunction in signal transduction and gene regulation network in polygenic tumors, indicating that in the category of pathogenesis,these tumors may further classify as the "Disease of gene signal transduction and gene regulation network disorder". The researches have laid solid foundation for revealing the molecular mechanism and transcriptomic regulation of polygenic tumors at different stages.

Zhang Y.,Central South University | Luo R.,Central South University
Journal of Constructional Steel Research | Year: 2012

Yandangshan Bridge is a tied-arch bridge of double-line railway with a (90 + 90) m continuous steel box girder and passes over a very busy highway in China. The incremental launching of the steel box girder of this bridge is a challenge for bridge builders, mainly because of the patch loading caused by large self-weight, large camber, unsymmetrical and flexible temporary transverse beams. Due to on-site working conditions, many commonly used measures cannot be taken for the launching of this bridge. The launching process is simulated using finite element method. The results have shown that significant local stress concentration would occur in the web plate and bottom plate of the girder if no improved measures are applied. The influencing factors of the stress concentration are studied. Four measures to reduce the local stress of the girder are presented and put into practice: to add two slide shoes on every pier; weld six short launching noses at the diaphragm of leading end of the box girder; pre-lift the 6 slide shoes on one temporary pier at different positions to eliminate part of the deflection of the temporary transverse beams, and use special adjustable slide shoes in one span. The whole launching process has been monitored and the measured stress and deformation coincide with the results of finite element analysis. Good effects have been obtained by applying the four improved measures. The incremental launching of the steel box girder of Yandangshan Bridge has been successful. © 2011 Elsevier Ltd.

Yang X.L.,Central South University | Huang F.,Central South University
Tunnelling and Underground Space Technology | Year: 2011

Collapse shape of shallow circular tunnel is derived using a new curved failure mechanism within the framework of upper bound theorem. Nonlinear Hoek-Brown failure criterion is adopted in the present analysis. With the consideration of supporting pressure, the energy dissipations of the new failure mechanism are calculated by employing integral technique. Equating the rate of energy dissipation to the external rate of work, the objective function is formulated, and is optimized with the variational approach. Numerical results are presented, and collapse mechanisms of shallow tunnel taking into account supporting pressure are obtained. The present results are compared with the previous solutions, and the agreement shows that the present method is valid. The effects of different parameters on the failure mechanisms are discussed, and a critical depth expression is proposed for classifying shallow and deep tunnels. © 2011 Elsevier Ltd.

Huang J.,Central South University | Yang Z.,Central South University | Wang T.,Central South University
Electrochimica Acta | Year: 2014

The cycle life of zinc anode in alkaline medium was enhanced by tetraphenylporphyrin (TPP) as modifier through a facile co-precipitation method. The as-prepared electrode material before and after charge/discharge test were characterized by scanning electron microscopy (SEM) to investigate the effect of TPP on the zinc dendrite growth. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and polarization measurement were utilized to examine the electrochemical performances of TPP-modified ZnO as anode material. TPP-modified ZnO possess higher discharge voltage, higher cycle stability and lower corrosion current, but larger charge-transfer resistance in comparison with bare ZnO. © 2014 Elsevier Ltd.

Huang F.,Central South University | Yang X.L.,Central South University
Tunnelling and Underground Space Technology | Year: 2011

Based on Hoek-Brown failure criterion and using the upper bound theorem of limit analysis, a numerical solution for the shape of collapsing block in circular tunnel subjected to pore pressure is derived. The effect of water pressure which is assumed to be a work rate of external force is included in the upper bound analysis. By employing variational calculation to minimize the objective function, the upper solution of collapsing block is obtained. In order to evaluate the validity of the method used in this paper, the result for pore pressure coefficient ru= 0, with no effect of pore pressure taken into account, is compared with previous work. The good agreement shows that the method of calculating the upper solution for the shape of collapsing block subjected to pore pressure is valid. © 2011 Elsevier Ltd.

Xu M.H.,Central South University
Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences | Year: 2011

To evaluate the efficacy of bismuth-based quadruple therapy as the first-line treatment for H.pylori infection. A total of 136 patients with H.pylori related peptic ulcer or chronic gastritis were randomized into two groups: 67 patients in bismuth-based quadruple group received esomeprazole 20 mg, clarithromycin 0.5 g,amoxicillin 1.0 g,and bismuth potassium citrate 220 mg for 7 d; 69 patients in standard triple group received esomeprazole 20 mg, clarithromycin 0.5 g and amoxicillin 1.0 g for 7 d. Outcome of eradication therapy was assessed by (14)C-UBT. On ITT and PP analysis, calculating the cost-effectiveness ratio (C/E) and the incremental cost-effectiveness ratio (delta C/delta E). On ITT and PP analysis, the eradication rates of the quadruple therapy group were 82.09% and 88.71%, and those of the triple therapy group were 66.67% and 73.02% (P<0.05). The cost-effectiveness ratio of two groups was 4.15 and 4.82; The incremental cost-effectiveness ratio of quadruple therapy group was 1.02 as against triple therapy group. Compared to the standard triple therapy regimen, the bismuth-containing quadruple therapy regimen has higher eradication rate and cost-effectiveness, which can be recommended as the fist-line treatment for H.pylori infection.

Cai S.,Central South University | Huang S.,Central South University | Hao W.,Central South University
Neuroscience Bulletin | Year: 2015

Major depressive disorder (MDD) is a common and devastating psychiatric disorder characterized by persistent low mood, cognitive disorder, and impaired social function. Despite its complex mechanisms, increasing evidence has identified the involvement of neurotrophic factors, inflammatory cytokines, the hypothalamus-pituitary-adrenal axis, and glutamate receptors in the pathophysiology of this illness. The present review synthesizes recent research achievements to define the network between different hypotheses of MDD and to understand which part is most pivotal for its pathogenesis. By integrating MDD-related signal pathways, we highlight brain-derived neurotrophic factor (BDNF) dysfunction and increased apoptosis as the final common cascades, and new therapeutic strategies aiming to enhance BDNF function have been shown to exert a rapid and effective antidepressant action. © 2015, Shanghai Institutes for Biological Sciences, CAS and Springer-Verlag Berlin Heidelberg.

Wang Z.,Central South University | Tian H.,Central South University | Lu Z.,Central South University | Zhou W.,Central South University
Composites Part B: Engineering | Year: 2014

This paper presents some significant research results about velocity sensitivity of aluminum honeycomb under high-speed axial impact in a velocity range from 20 to 80 m/s. Series experiments were carried out with the help of self-developed high-speed impact system. Afterwards, corresponding numerical simulation works as well as some parametric studies were conducted. The resultant comparison told out that the plateau stress increases markedly when impact below 30 m/s, but slowly when impact at a velocity various from 30 to 80 m/s. Before the parametric studies, inertial effect in various impact masses was investigated. Comparison between parametric results showed that the promotion on Specific Load and energy-absorbing capability increases with the impact velocity for various honeycombs. Density also has a great influence on Specific Load. The higher honeycomb density is, the greater amplitude performs. The energy absorption diagram for honeycomb with different geometric configurations reveals the relationship between dynamic plane stress and energy per unit volume, and also proves the promotion with increasing of impact velocity. © 2013 Elsevier Ltd. All rights reserved.

Tan C.,Central South University
Expert Systems with Applications | Year: 2011

An extension of TOPSIS, a multi-criteria interval-valued intuitionistic fuzzy decision making technique, to a group decision environment is investigated, where inter-dependent or interactive characteristics among criteria and preference of decision makers are taken into account. To get a broad view of the techniques used, first, some operational laws on interval-valued intuitionistic fuzzy values are introduced. Based on these operational laws, a generalized interval-valued intuitionistic fuzzy geometric aggregation operator is proposed which is used to aggregate decision makers' opinions in group decision making process. In addition, some of its properties are discussed. Then Choquet integral-based Hamming distance between interval-valued intuitionistic fuzzy values is defined. Combining the interval-valued intuitionistic fuzzy geometric aggregation operator with Choquet integral-based Hamming distance, an extension of TOPSIS method is developed to deal with a multi-criteria interval-valued intuitionistic fuzzy group decision making problems. Finally, an illustrative example is used to illustrate the developed procedures. © 2010 Elsevier Ltd. All rights reserved.

Ding Y.,Central South University
Nan fang yi ke da xue xue bao = Journal of Southern Medical University | Year: 2012

To observe the changes of miRNA expression profiles in APPswe/PSδE9 transgenic mice and explore the possible roles of miRNA in the pathogenesis of Alzheimer's disease. Using miRNA chip technique, we examined the miRNA expression in the brain tissue of 6-month-old APPswe/PSδE9 transgenic mice, with age-matched wild-type mice as the control group. Twelve miRNAs showed differential expressions by more than two folds in APPswe/PSδE9 transgenic mice, namely miRNA-135a, miRNA-135a-2*, miRNA-298, miRNA-466b-3p, miR-669-3p, miR-142-5p, miR-144, miR-466f-3p, miR-466g, miR-200a, miR-200b and miR-96. Five miRNAs were significantly down-regulated in the transgenic mice, including miRNA-135a, miRNA-135a-2*, miRNA-298, miRNA-466b-3p, and miR-669-3p. The 5 down- regulated miRNA may play important roles in the pathogenesis of AD in APPswe/PSδE9 transgenic mice.

To clarify the role of IGF-2 on the development of myopia, the dynamic expression of IGF-2 was investigated in the FD eyes' retina, and the effects of intravitreous injection with IGF-2 ASON was studied on the diopter and axial eye length of FD eyes. 64 guinea pigs were divided into 2 groups. In group A (n = 24), the right eyes were covered. On days 7, 14 and 21, the diopter, axial eye length and level of IGF-2 of both eyes were measured in every 8 guinea pigs. In group B (n = 40), the right eyes were covered. On day 1, the right eyes were received intravitreal injection with 40 μg IGF-2SON, 10 μg, 20 μg or 40 μg IGF-2 ASON. The diopter, axial eye length and level of IGF-2 were measured on day 14. FD eyes showed myopic shift, axial length enlongation, and up-regulation in retinal IGF-2 from day 7 to day 21. The level of retinal IGF-2 in FD eyes was higher than that in non-FD eyes. Compare with FD eyes without injection, the myopia diopter of FD eyes decreased in received intravitreous injection with IGF-2 ASON, axial length shortened, and down-regulated with retinal IGF-2. With the increase dose of IGF-2 ASON, the change of myopic diopter, axial length, and level of retinal IGF-2 were showed more and more significant. FD is effective to up-regulate the level of retinal IGF-2 expression in guinea pig. Intravitreous injection with IGF-2 ASON can inhibit the development of myopia. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

The changes in the capacitance and the dielectric constant of multi-wall carbon nanotube filled silicone rubber composite during the compressive creep are studied. At the moment of the sudden compression, the capacitance and the dielectric constant decrease instantaneously, and the absolute values of the instantaneous decrements increase with the increase of the sudden compressive pressure. When the compressive pressure holds constant, the capacitance and the dielectric constant increase gradually and tend to be stable over time. Based on the viscoelastic theory, the mathematical model for the variations in the dielectric constant during the compressive creep is established. With the increase of the sudden compressive pressure, the dielectric constant retardation times hold constant and the stable normalized dielectric constant increases. With the increase of the carbon nanotube volume percent, the dielectric constant retardation times and the stable normalized dielectric constant decreases. © 2016 Elsevier Ltd.

Wang J.-Q.,Central South University | Li J.-J.,Central South University
Expert Systems with Applications | Year: 2011

The Limitations and deficiencies of existing score functions of intuitionistic fuzzy set are analyzed. Based on the two theories of intuitionistic fuzzy set and cross entropy, with the adoption of cross entropy of the degree of membership from the degree of non-membership handling the effect of hesitancy degree, two improved methods handling multicriteria fuzzy decision-making problem are provided. They are called score function method and weighted score function method. Finally, examples are given showing that the methods presented in this paper are more efficient and advantageous. © 2010 Elsevier Ltd. All rights reserved.

Li X.-F.,Central South University | Kang Y.-A.,Central South University | Wu J.-X.,Central South University
Applied Acoustics | Year: 2013

Free vibration of axially inhomogeneous beams is analyzed. For exponentially graded beams with various end conditions, characteristic equations are derived in closed form. These characteristic or frequency equations can analytically reduce to the classical forms of Euler-Bernoulli beams if the gradient index disappears. The gradient has a strong influence on the frequency spectrum, and the natural frequencies noticeably depend on the variation of the gradient parameter and end support conditions. For certain beams with exponential gradients, there exists a critical frequency depending on the gradient parameter. Vibration can be only excited by propagating waves with frequencies in excess of the critical frequency, and otherwise vibration is prohibited for pseudo-frequencies lower than the critical frequency. For some gradient index with small change, the natural frequencies have an abrupt jump when across its critical frequencies. Obtained results can serve as a benchmark for other numerical procedures for analyzing transverse vibration of axially functionally graded beams. The minimal natural frequency can be sought for certain gradient index, and this helps engineers to optimally design vibrating nonhomogeneous beam structures. Obtained results also apply to free vibration of nonuniform beams with constant thickness and exponentially decaying width. © 2012 Elsevier Ltd. All rights reserved.

Liu Y.-P.,Central South University | Li K.-H.,Central South University | Sun B.-H.,Central South University
Clinical Orthopaedics and Related Research | Year: 2012

Background: Intralesional excision and en bloc resection are used to treat giant cell tumors (GCTs) of the distal radius. However, it is unclear whether one provides lower rates of recurrences and fewer complications, and whether the use of polymethylmethacrylate (PMMA) after curettage reduces the risk of recurrence. Questions/Purposes: We examined whether curettage was associated with lower rates of recurrence and fewer major complications compared with en bloc excision, and whether PMMA resulted in lower rates of recurrence compared with a bone graft. Methods: We systematically searched the literature using the criteria, giant cell tumor AND curettage OR intralesional excision OR resection. Six relevant articles were identified that reported data for 80 curettage cases (PMMA, n = 49; bone graft, n = 26; no PMMA or bone grafts, n = 5) and 59 involving en bloc excision. A meta-analysis was performed using these data. Results: Overall, patients in the intralesional excision group had a higher recurrence rate (relative risk [RR], 2.80; 95% CI, 1.17-6.71), especially for Campanacci Grade 3 GCTs (RR, 4.90; 95% CI, 1.36-17.66), yet fewer major complications (RR, 0.21; 95% CI, 0.09-0.54) than the en bloc resection group. The use of PMMA versus bone graft did not affect the recurrence rate (RR, 0.98; 95% CI, 0.44-2.17). Conclusions: Based on data obtained from the limited number of studies available, intralesional excision appears to be more appropriate for the treatment of local lesions (eg, Grades 1 and 2) than Grade 3 GCTs of the distal radius. Moreover, PMMA was not additionally effective as an adjuvant. Level of Evidence: Level III, therapeutic study (systematic review). See Guidelines for Authors for a complete description of levels of evidence. © 2012 The Association of Bone and Joint Surgeons®.

Zhou P.,Central South University | Gong H.R.,Central South University
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2012

First principle calculations reveal that Mg-Ca phases are energetically favorable with negative heats of formation within the entire composition range, and that a strong chemical bonding is formed between Mg and Ca atoms. Calculations also show that the