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Zhejiang University , sometimes referred to as Zheda, is a national university in China. Founded in 1897, Zhejiang University is one of China's oldest institutions of higher education. It is a member of the C9 League and Yangtze Delta Universities Alliance. The university campus is located in the city of Hangzhou, approximately 112 miles southwest of Shanghai. Zhejiang University Library collection contains about 7 million volumes, making it one of the largest academic libraries in the country. Wikipedia.

Dai J.,Zhejiang University | Zhang S.,Iowa State University
Optics and Lasers in Engineering | Year: 2013

Our recent study showed that the Bayer-dithering technique could substantially improve 3D measurement quality for the binary defocusing method. Yet, the dithering technique was developed to optimize the appearance or intensity representation, rather than the phase, of an image. This paper presents a framework to optimize the Bayer-dithering technique in phase domain by iteratively mutating the status (0 or 1) of a binary pixel. We will demonstrate that the proposed optimization technique can drastically reduce the phase error when the projector is nearly focused. © 2013 Elsevier Ltd.

Rao C.,Zhejiang University
Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences | Year: 2013

TGF-β signaling pathway plays a central role in the signaling networks that control the growth, differentiation of the cell, and the initiation of fibrosis and cancer. Wnt signaling pathway is critical for the embryonic development and the invasion and migration of cancer cells. TGF-β signaling and Wnt signaling, both of which play an important role in regulating embryonic development, fibrotic disease and tumor progression, have a close relationship. Researches find several typical cross points between these two signaling systems, such as Smad, Axin, Dvl and β-catenin. In this review, we focus on the crosstalk between TGF-β signaling and Wnt signaling through these typical factors, intending to better understand the process of fibrosis and tumor progression.

Lin H.,Zhejiang University
Computer Aided Geometric Design | Year: 2010

Just by adjusting the control points iteratively, progressive-iterative approximation presents an intuitive and straightforward way to fit data points. It generates a curve or patch sequence with finer and finer precision, and the limit of the sequence interpolates the data points. The progressive-iterative approximation brings more flexibility for shape controlling in data fitting. In this paper, we design a local progressive-iterative approximation format, and show that the local format is convergent for the blending curve with normalized totally positive basis, and the bi-cubic B-spline patch, which is the most commonly used patch in geometric design. Moreover, a special adjustment manner is designed to make the local progressive-iterative approximation format is convergent for a generic blending patch with normalized totally positive basis. The local progressive-iterative approximation format adjusts only a part of the control points of a blending curve or patch, and the limit curve or patch interpolates the corresponding data points. Based on the local format, data points can be fit adaptively. © 2010 Elsevier B.V. All rights reserved.

Chu K.,Zhejiang University
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques | Year: 2012

Cytokines, which are involved in immunological responses, play and important role in the development and progression of Parkinson's disease (PD). The functional polymorphisms identified in cytokine genes are thought to influence PD risk. However the findings of studies investigating the association between cytokine gene polymorphisms and PD risk are still controversial. Therefore, we conducted a meta-analysis, in order to investigate the potential associations between cytokine gene polymorphisms and PD. Studies of PD and cytokine polymorphisms were identified by searches of PubMed and PDGene. Pooled analyses were performed to assess the association between cytokine gene polymorphisms and PD. Our results indicated a positive association of TNFα -1031 CC genotype in overall analysis(CC vs. TT: OR=3.146; 95%CI: 1.631-6.070, p=0.008; CC vs. CT+TT: OR=3.187: 95%CI: 1.657-6.128,p=0.008), and an Asian subgroup, C variant(OR=1.328; 95%CI: 1.053-1.675, p=0.034) also conveyed an increased PD risk as well as CC genotype ( CC vs. TT: OR=3.207; 95%CI: 1.614-6.373, p=0.004; CC vs. CT+TT: OR=3.238; 95%CI: 1.636-6.410, p=0.004). A decreased risk for PD was associated with IL-6-174C allele (OR=0.761; 95%CI: 0.641-0.903, p=0.008) and IL-1RA VNTR 2 allele(OR=0.641; 95%CI: 0.456-0.826 p=0.004). For the polymorphisms of IL-1β C[-511]T, IL-1α C[-889]T , TNFα G[-308]A, and IL-10 G[-1082]A no significant association was found between the gene polymorphisms and PD risk. Our meta-analysis suggested that gene polymorphisms of TNFα -1031, IL-6-174 and IL-1RA VNTR may be associated with PD risk. However, more large well-designed studies will be necessary to validate our findings.

Xie Z.W.,Zhejiang University
The Journal of international medical research | Year: 2012

To evaluate the efficacy of a levonorgestrel-releasing intrauterine device (LNG-IUD) as contraception for women with uterine leiomyoma. Thirty women with uterine leiomyoma requiring contraception were enrolled and had a LNG-IUD inserted. Menstrual blood volume (assessed by a pictorial blood loss assessment chart [PBAC]), haemoglobin concentration, volume of uterus and leiomyoma were determined before and after LNG-IUD insertion. The median (range) PBAC score was 145.0 (60.0-232.0) before LNG-IUD insertion, which significantly decreased to 44.0 (0.0-99.0) and 36.0 (0.0-90.0) after 6 and 12 months of LNG-IUD use, respectively. Prior to LNG-IUD insertion, the median haemoglobin concentration in patients with anaemia was 100.0 (69.0-109.0) g/l and this increased significantly after 6 and 12 months of LNG-IUD use, to 117.5 (101.0-131.0) g/l and 119.5 (108.0-135.0) g/l, respectively. There were no significant changes in uterine or leiomyoma volumes. No patient became pregnant and there were no severe side-effects; one IUD was expulsed. The LNG-IUD may be a safe and effective contraceptive for women of reproductive age with uterine leiomyoma.

Li J.-M.,Zhejiang University
Nanotechnology | Year: 2010

The author reports the first all-ZnO microtetrapod-on-nanowire hybrids using the cost-effective Au nanoseed assisted open static atmospheric pressure vapor transport method. The unconventional ZnO flower analogue hybrid structure consists of center-tapered ZnO microtetrapods (typically 1-2 m in dimension) on ZnO 'backbone' nanowires (typically 20 nm in diameter). Three new Raman peaks, centered at 225, 275, 561 cm- 1, never seen before in ZnO nanocrystals, were first observed in the ZnO hybrids. The hybrids exhibit excellent luminescent properties with a single ultraviolet emission band centered at about 377 nm with an ultra-narrow full width at half maximum of ∼ 4 nm, which makes it a promising candidate for optoelectronic applications. A preliminary self-assembled synergic growth mechanism is proposed to understand the formation of the structurally stable morphology where the vapor-liquid-solid and vapor-solid mode work together. Our results could open up possibilities for making ZnO nanocrystals to a new level of more complex nanoarchitectures. © 2010 IOP Publishing Ltd.

Cao C.,Hangzhou Normal University | Dai J.,Hangzhou Normal University | Dai J.,Zhejiang University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Electronic structure and magnetic properties for iron-deficient TlFe 2-xSe2 compounds are studied by first-principles calculations. We find that for the case of x=0.5 with a Fe vacancy ordered orthorhombic superstructure, the ground state exhibits a stripelike antiferromagnetic ordering and opens a sizable band gap if the short-ranged Coulomb interaction of Fe-3d electrons is moderately strong, manifesting a possible Mott insulating state. While increasing Fe vacancies from the x=0 side, where the band structure is similar to that of a heavily electron-doped FeSe system, the Mott localization can be driven by kinetic energy reduction, as evidenced by the band narrowing effect. Implications of this scenario in the recent experiments on TlFe2-xSe2 are discussed. © 2011 American Physical Society.

Hao J.,KTH Royal Institute of Technology | Zhou L.,Fudan University | Qiu M.,KTH Royal Institute of Technology | Qiu M.,Zhejiang University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We theoretically and numerically study the absorption effect and the heat generation in plasmonic metamaterials under light radiation at their plasmonic resonance. Three different types of structures, all possessing high-performance absorption for visible lights, are investigated. The main aim of this work is to present an intuitive and original understanding of the high-performance absorption effects. From the macroscopic electromagnetic point of view, the effective-medium approach is used to describe the absorption effects of the plasmonic metamaterials. On the other hand, the field distributions and heat generation effects in such plasmonic nanostructures are investigated, which also provides a satisfactory qualitative description of such absorption behavior based upon the microscopic perspective. © 2011 American Physical Society.

Dai D.,Zhejiang University | Bowers J.E.,University of California at Santa Barbara
Nanophotonics | Year: 2014

An effective solution to enhance the capacity of an optical-interconnect link is utilizing advanced multiplexing technologies, like wavelength-division-multiplexing (WDM), polarization-division multiplexing (PDM), spatial-division multiplexing (SDM), bi-directional multiplexing, etc. On-chip (de)multiplexers are necessary as key components for realizing these multiplexing systems and they are desired to have small footprints due to the limited physical space for on-chip optical interconnects. As silicon photonics has provided a very attractive platform to build ultrasmall photonic integrated devices with CMOS-compatible processes, in this paper we focus on the discussion of silicon-based (de)multiplexers, including WDM filters, PDM devices, and SDM devices. The demand of devices to realize a hybrid multiplexing technology (combining WDM, PDM and SDM) as well as a bidirectional multiplexing technologies are also discussed to achieve Peta-bit optical interconnects. © 2014 Science Wise Publishing & De Gruyter.

Li W.,Zhejiang University
Chinese medical journal | Year: 2012

Primary tracheal tumors are relatively rare. Here we report one case of primary adenoid cystic carcinoma of the trachea which was ever misdiagnosed as asthma and hysteria. In this case, the pulmonary function test was normal, and firstly no obvious abnormalities were found in laryngoscopy, bronchoscopy and CT scan of chest. Later a sagittal and coronal reconstruction CT scan of trachea showed a mass situated in the subglottic trachea. Lastly a laryngoscopy was again done after a tracheal incision and showed a small mass in the posterior wall of the subglottic trachea, and tumor ablation was performed. In addition, we reviewed the literature of primary tracheal tumors and summarized the epidemiology, presenting features, available therapeutic options of the disease.

Li H.,Zhejiang University | Giri G.,Stanford University | Tok J.B.-H.,Stanford University | Bao Z.,Stanford University
MRS Bulletin | Year: 2013

High-mobility organic field-effect transistors (OFETs) are the basic units for a variety of high-performance electronic applications. Here, we review recent progress in controlling molecular packing and crystal growth in high-mobility, small molecular organic FETs. Strategies to tune molecular packing of organic semiconductors and their impact on charge transport are described. Methods for the controlled growth of single-crystal organic semiconductors required for large-area device construction are reviewed. Furthermore, the advantages, limitations, and potential of these methods are also discussed. © 2013 Materials Research Society.

Li Y.-C.,Zhejiang University | Cleall P.J.,University of Cardiff
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2010

Analytical solutions for conservative solute diffusion in one-dimensional double-layered porous media are presented in this paper. These solutions are applicable to various combinations of fixed solute concentration and zero-flux boundary conditions (BC) applied at each end of a finite one-dimensional domain and can consider arbitrary initial solute concentration distributions throughout the media. Several analytical solutions based on several initial and BCs are presented based on typical contaminant transport problems found in geoenvironmental engineering including (1) leachate diffusion in a compacted clay liner (CCL) and an underlying stratum; (2) contaminant removal from soil layers; and (3) contaminant diffusion in a capping layer and underlying contaminated sediments. The analytical solutions are verified against numerical solutions from a finite-element method based model. Problems related to leachate transport in a CCL and an underlying stratum of a landfill and contaminant transport through a capping layer over contaminated sediments are then investigated, and the suitable definition of the average degree of diffusion is considered. © 2010 ASCE.

Xu C.,Zhejiang University
Hepatology International | Year: 2016

Uric acid is the end product of dietary or endogenous purines degradation, and hyperuricemia is one of the most common metabolic disorders. It has been widely accepted that hyperuricemia increases risks of gout, cardiovascular diseases, and type 2 diabetes. A growing body of evidence, comprising a great deal of cross-sectional studies and several prospective ones, also indicates that hyperuricemia is associated with increased prevalence, incidence and disease severity of non-alcoholic fatty liver disease (NAFLD). On the contrary, NAFLD can predict hyperuricemia as well. However, no causal relationship can be drawn from this point. With a well-established relationship between uric acid and NAFLD prevalence as well as disease severity in addition to the role of potential therapeutic target, the prognostic role of uric acid is also worth investigating. Further studies should focus on the prospective role of uric acid on NAFLD progression and its underlying mechanisms, as well as its clinical implications. © 2015, Asian Pacific Association for the Study of the Liver.

Vo H.T.,National University of Singapore | Chen C.,Zhejiang University | Ooi B.C.,National University of Singapore
Proceedings of the VLDB Endowment | Year: 2010

Cloud storage is an emerging infrastructure that offers Platforms as a Service (PaaS). On such platforms, storage and compute power are adjusted dynamically, and therefore it is important to build a highly scalable and reliable storage that can elastically scale ondemand with minimal startup cost. In this paper, we propose ecStore - an elastic cloud storage system that supports automated data partitioning and replication, load balancing, efficient range query, and transactional access. In ecStore, data objects are distributed and replicated in a cluster of commodity computer nodes located in the cloud. Users can access data via transactions which bundle read and write operations on multiple data items stored on possibly different cluster nodes. The architecture of ecStore follows a stratum design that leverages an underlying distributed index with a replication layer in the middle and a transaction management layer on top. ecStore provides adaptive read consistency on replicated data. We also enhance the system with an effective load balancing scheme using a self-tuning replication technique that is specially designed for large-scale data. Furthermore, a multi-version optimistic concurrency control scheme matches well with the characteristics of data in cloud storages. To validate the performance of the system, we have conducted extensive experiments on various platforms including a commercial cloud (Amazon's EC2), an in-house cluster, and PlanetLab. © 2010 VLDB Endowment.

Hu Y.L.,Zhejiang University
International journal of nanomedicine | Year: 2011

Although there are a number of reports regarding the toxicity evaluation of inorganic nanoparticles, knowledge on biodegradable nanomaterials, which have always been considered safe, is still limited. For example, the toxicity of chitosan nanoparticles, one of the most widely used drug/gene delivery vehicles, is largely unknown. In the present study, the zebrafish model was used for a safety evaluation of this nanocarrier. Chitosan nanoparticles with two particle sizes were prepared by ionic cross-linking of chitosan with sodium tripolyphosphate. Chitosan nanoparticles of different concentrations were incubated with zebrafish embryos, and ZnO nanoparticles were used as the positive control. Embryo exposure to chitosan nanoparticles and ZnO nanoparticles resulted in a decreased hatching rate and increased mortality, which was concentration-dependent. Chitosan nanoparticles at a size of 200 nm caused malformations, including a bent spine, pericardial edema, and an opaque yolk in zebrafish embryos. Furthermore, embryos exposed to chitosan nanoparticles showed an increased rate of cell death, high expression of reactive oxygen species, as well as overexpression of heat shock protein 70, indicating that chitosan nanoparticles can cause physiological stress in zebrafish. The results also suggest that the toxicity of biodegradable nanocarriers such as chitosan nanoparticles must be addressed, especially considering the in vivo distribution of these nanoscaled particles. Our results add new insights into the potential toxicity of nanoparticles produced by biodegradable materials, and may help us to understand better the nanotoxicity of drug delivery carriers.

Jin M.,Washington University in St. Louis | Jin M.,Xiamen University | Zhang H.,Washington University in St. Louis | Zhang H.,Zhejiang University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Curvy cubes: Palladium concave nanocubes enclosed by high-index {730} facets were obtained in high purity by controlling the overgrowth of Pd cubic seeds (see scheme). The concave nanocubes showed a much higher catalytic activity than the conventional Pd nanocubes enclosed by {100} facets for both electro-oxidation of formic acid and Suzuki coupling reaction. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gong X.-N.,Zhejiang University
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

The investigation report about the application of numerical analysis of geotechnical engineering in China was introduced firstly. Then the key of analyzing geotechnical problems with continuum mechanics and the current situation of geotechnical constitutive theory were discussed; the developing directions of geotechnical constitutive theory was put forward. Finally, the status of numerical simulation in the geotechnical engineering was evaluated. Through above discussions it can be concluded that, the result of numerical analysis is one of the most important back ground for the engineering judgment of geotechnical engineers in the geotechnical engineering analysis; the key of analyzing geotechnical problems with continuum mechanics is to establish simple and practical engineering constitutive model. Establishing many simple and practical engineering constitutive models and accumulating a lot of engineering experience, numerical analysis can be used in geotechnical engineering from qualitative to quantitative.

Chen Z.H.,Zhejiang University
Respirology (Carlton, Vic.) | Year: 2013

Asthma is one of the most common chronic diseases worldwide with increasing morbidity. China has the largest asthmatic population and is one of the countries with the highest asthma mortality. Fortunately, asthma research in China, both clinical and scientific, has developed markedly over the past few years. This has resulted in significant increases in our understanding of Chinese asthma prevalence, risk factors, control status, pathogenesis, and new prevention or treatment strategies. In this review, the major achievements of asthma research in China from 2008 to 2012 are summarized. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

Khan Y.,Zhejiang University
International Journal of Numerical Methods for Heat and Fluid Flow | Year: 2014

Purpose - This paper aims to suggest a novel modified Laplace decomposition method (MLDM) for MHD flow over a non-linear stretching sheet with slip condition by suitable choice of an initial solution. Design/methodology/approach - The governing partial differential equations are converted into dimensionless non-linear ordinary differential equation by similarity transformation, which is solved by MLDM. The method is based on the application of Laplace transform to boundary layers in fluid mechanics. The non-linear term can be easily handled by the use of He's polynomials. Findings - The series solution of the MHD flow of an incompressible viscous fluid over a non-linear stretching sheet subject to slip condition is obtained. An excellent agreement between the MLDM and HPM is achieved. Convergence of the obtained series solution is properly checked by using the ratio test. Practical implications - Stretching surface is an important type of flow occurring in a number of engineering processes such as heat-treated materials travelling between a feed roll and a wind up roll, aerodynamic extrusion of plastic sheets, glass fiber and paper production, cooling of an infinite metallic plate in a cooling path, manufacturing of polymeric sheets are few examples of flow due to stretching surfaces. This work provides a very useful source of information for researchers on this subject. Originality/value - Such flow analysis is even not available yet for the hydrodynamic fluid. The series solution for MHD boundary layer problem with slip condition by means of MLDM is yet not available in the literature. Copyright © 2014 Emerald Group Publishing Limited. All rights reserved.

Gao Q.,Zhejiang University
Molecular and cellular biochemistry | Year: 2012

Oral administration of Clostridium butyricum as probiotic is increasingly gaining importance in the treatment of diarrhea and the improvement of animal performance. However, the mechanisms of host cell receptor recognition of C. butyricum and the downstream immune signaling pathways leading to these benefits remain unclear. The objective of this study was to analyze the mechanisms involved in C. butyricum induction of the toll-like receptor (TLR) signaling. Knockdown of myeloid differentiation primary response protein 88 (MyD88) expression using small interfering RNA in this manner did not affect C. butyricum-induced elevated levels of nuclear factor κB (NF-κB), interleukin-8 (IL-8), IL-6, and tumor necrosis factor alpha (TNF-α), suggesting a MyD88-independent route to TLR signaling transduction. However, a significant reduction in the levels of NF-κB, IL-8, IL-6, and TNF-α was evident in the absence of TLR2 expression, implying the need for TLR2 in C. butyricum recognition. Hence, C. butyricum activates TLR2-mediated MyD88-independent signaling pathway in human epithelial cells, which adds to our understanding of the molecular mechanisms of this probiotic action on gut epithelium.

You K.,Nanyang Technological University | Fu M.,Zhejiang University | Fu M.,University of Newcastle | Xie L.,Nanyang Technological University
Automatica | Year: 2011

This paper studies the stability of Kalman filtering over a network subject to random packet losses, which are modeled by a time-homogeneous ergodic Markov process. For second-order systems, necessary and sufficient conditions for stability of the mean estimation error covariance matrices are derived by taking into account the system structure. While for certain classes of higher-order systems, necessary and sufficient conditions are also provided to ensure stability of the mean estimation error covariance matrices. All stability criteria are expressed by simple inequalities in terms of the largest eigenvalue of the open loop matrix and transition probabilities of the Markov process. Their implications and relationships with related results in the literature are discussed. © 2011 Elsevier Ltd. All rights reserved.

Li Y.,South China University of Technology | Gecevicius M.,South China University of Technology | Qiu J.,South China University of Technology | Qiu J.,Zhejiang University
Chemical Society Reviews | Year: 2016

Owing to the unique mechanism of photoelectron storage and release, long persistent phosphorescence, also called long persistent luminescence or long lasting afterglow/phosphorescence, plays a pivotal role in the areas of spectroscopy, photochemistry, photonics and materials science. In recent years, more research has focused on the manipulation of the morphology, operational wavebands and persistent duration of long persistent phosphors (LPPs). These desired achievements stimulated the growing interest in designing bio-labels, photocatalysts, optical sensors, detectors and photonic devices. In this review, we present multidisciplinary research on synthetic methods, afterglow mechanisms, characterization techniques, materials system, and applications of LPPs. First, we introduce the recent developments in LPPs for the synthesis of nanoparticles from the aspects of particle sizes, monodispersity and homogeneity based on the urgent application of bio-imaging. In the later sections, we present the possible mechanisms, which involve the variation of trap distribution during the trapping and de-trapping process, complicated photo-ionization reaction of trap site levels and impurity centers together with their corresponding migration kinetics of carriers. Meanwhile, we emphasize the characterization techniques of defects, used to qualitatively or quantitatively describe the types, concentrations and depths of the traps. This review article also highlights the recent advances in suggested LPPs materials with a focus on the LPPs' hosts and optically active centers as well as their control, tuning and intrinsic links. We further discuss the classification of LPPs based on the different emission and excitation wavebands from the ultraviolet to the near-infrared region along with an overview of the activation mode of afterglow. Afterwards, we provide an exhibition of new products towards diverse application fields, including solar energy utilization, bio-imaging, diagnosis, and photocatalysts. Finally, we summarize the current achievements, discuss the problems and provide suggestions for potential future directions in the aforementioned parts. © The Royal Society of Chemistry 2016.

Water-soluble, monodispersed, and bluish green-emitting Au(10) nanoclusters were synthesized through a simple reaction, in which histidine served as both a reducing agent and a protecting ligand. UV-visible absorption, photoluminescence, electrospray ionization (ESI) mass spectrometry, and X-ray photoelectron spectroscopy (XPS) were carried out to demonstrate the chemical composition and optical properties of the Au(10) clusters. The mechanism of this proposed reaction was explored and the reducing ability of histidine was proved from its imidazole group. Finally, the fluorescence of Au NCs at different reaction times, pH value, and temperature was measured in situ. Then a synthetic strategy was proposed for gold nanoclusters with a defined chemical composition, and the resulting Au(10) clusters stabilized by histidine are biocompatible with bioorganisms, showing a great potential for applications such as biological labeling and biosensors.

Objective: To compare the outcome of patients with dry traumatic tympanic membrane perforation after spontaneous healing and gelfoam patching with or without perforation edge approximation. Design: Prospective clinical study. Setting: University-affiliated teaching hospital. Participants: Ninety-one patients with acute dry traumatic tympanic membrane perforation inverted or everted edges were recruited. They were randomly allocated to three groups: spontaneous healing (n=31), gelfoam patching (n=30) and edge-approximation plus gelfoam patching (n=30). Otoscopy and tympanometry were performed before the treatment and at follow-up visits. Main outcome measures: Healing rate, healing time, ear infection rate and morphological changes during healing process. Results: The overall healing rate was 85% in the spontaneous healing group, lower than that in the two gelfoam patching groups (97%), but the difference failed to reach a statistical significance (P>0.05). The average healing time was 30±10.1days in the spontaneous healing group, significantly longer (P<0.01) than that in the other two groups (16±5.6 and 18±4.7days, respectively). Middle ear infection rate did not differ significantly (7%, 3% and 3%, respectively). Spontaneous healing resulted in formation of scabs at the perforation edges, which was effectively prevented by gelfoam patching. Conclusions: Gelfoam patching may facilitate healing of traumatically perforated tympanic membrane. Approximation of folded perforation edges is not necessary in gelfoam patching. © 2011 Blackwell Publishing Ltd.

Wang W.,Zhejiang University
Journal of Geometry and Physics | Year: 2010

By using complex geometric method associated to the Penrose transformation, we give a complete derivation of an exact sequence over C4 n, whose associated differential complex over Hn is the k-Cauchy-Fueter complex with the first operator D0(k) annihilating k-regular functions. D0(1) is the usual Cauchy-Fueter operator and 1-regular functions are quaternionic regular functions. We also show that the k-Cauchy-Fueter complex is elliptic. By using the fundamental solutions to the Laplacian operators of 4-order associated to the k-Cauchy-Fueter complex, we can establish the corresponding Bochner-Martinelli integral representation formula, solve the non-homogeneous k-Cauchy-Fueter equations and prove the Hartogs extension phenomenon for k-regular functions in any bounded domain. © 2009 Elsevier B.V. All rights reserved.

PURPOSE:: To evaluate the safety and efficacy of posterior continuous curvilinear capsulorhexis through the pars plana and 23-gauge vitrectomy in surgical management of dense posterior capsule opacification and vitreous floaters. METHODS:: Fifteen pseudophakic eyes of 15 patients with dense posterior capsule opacification and vitreous floaters between September 2012 and June 2014 were included; after vitrectomy, posterior continuous curvilinear capsulorhexis through the pars plana was performed. Data were collected, including baseline preoperative characteristics, postoperative outcomes, complications, and a modified quality-of-life survey that patients completed. RESULTS:: No intraoperative or postoperative complications were encountered in any of the 15 cases. Mean Snellen best-corrected visual acuity was 20/250 preoperatively and improved to 20/32 postoperatively (P < 0.001). All patients showed normal intraocular pressure 7 days after the procedure. The mean overall corneal endothelial cell loss at postoperative Month 3 was 1.2%. Approximately 80% of the patients had no complaint of vitreous floaters after the procedure. Except for 1 patient (7%) diagnosed with age-related macular degeneration, the rest of the patients (93%) were satisfied with the procedure and would recommend it to friends with dense posterior capsule opacification and vitreous floaters. CONCLUSION:: Posterior continuous curvilinear capsulorhexis through the pars plana combined with 23-gauge vitrectomy may be used to remove dense posterior capsule opacification and vitreous floaters in pseudophakic eyes. © 2016 by Ophthalmic Communications Society, Inc.

Zhou H.,Zhejiang University
Journal of Zhejiang University. Science. B | Year: 2013

Evergreen azaleas are among the most important ornamental shrubs in China. Today, there are probably over 300 cultivars preserved in different nurseries, but with little information available on the cultivar itself or relationships between cultivars. Amplified fragment length polymorphism (AFLP) markers were employed to determine the genetic relationships between evergreen azalea cultivars in China. One hundred and thirty genotypes collected from gardens and nurseries, including cultivars classified in the groups East, West, Hairy, and Summer, unknown cultivars, and close species, were analyzed using three primer pairs. A total of 408 polymorphic fragments were generated by AFLP reactions with an average of 136 fragments per primer pair. The average values of expected heterozygosity and Shannon's information index were 0.3395 and 0.5153, respectively. Genetic similarities were generated based on Dice coefficients, used to construct a neighbor joining tree, and bootstrapped for 100 replicates in Treecon V1.3b. Principal coordinate analysis (PCO) was performed based on Dice distances using NTSYS-pc software. The AFLP technique was useful for analyzing genetic diversity in evergreen azaleas. Cluster analysis revealed that cultivars in the West and Summer groups were quite distinct from other groups in the four-group classification system and that the East and Hairy groups should be redefined.

Tang X.J.,Zhejiang University
International journal of pharmaceutics | Year: 2013

To improve the solubility, stability and the antitumor activity of a novel anticancer drug, 3-(4-bromopheny l)-2-(ethyl-sulfonyl)-6-methylquinoxaline1,4-dioxide (Q39), a poloxamer nanosuspension was developed by precipitation combined with high pressure homogenization in present study. In vitro characterizations of Q39 nanosuspension (Q39/NS), including particle size, polydispersity index (PI), morphology, crystalline, saturation solubility, stability and releases were evaluated. BABL/c nude mice bearing HepG2 cells were used as in vivo tumor models to evaluate the anti-tumor activity of Q39/NS after intravenous administration. The particle size and PI for Poloxamer188 nanosuspension (P188/NS) were (304±3) nm, and (0.123±0.005) respectively, and it was (307±5) nm and (0.120±0.007) for Poloxamer85 nanosuspension (P85/NS) correspondingly. The morphology of P188/NS was spherical shape while elliptoid shape for P85/NS. The crystalline of Q39/NS did not change as shown by the X-ray diffraction analysis. The stability of Q39/NS improved compared with the solution. The solubility of Q39 in P188/NS was 7.3 times higher than the original solubility, while it was 6 times for P85/NS. Sustained release as shown from the in vitro release test, together with the tumor-targeting as shown from in vivo NS distribution, may contribute to the enhanced in vivo antitumor activity of Q39/NS. Copyright © 2013 Elsevier B.V. All rights reserved.

Kong W.,Zhejiang University
Sensors (Basel, Switzerland) | Year: 2013

A near-infrared (NIR) hyperspectral imaging system was developed in this study. NIR hyperspectral imaging combined with multivariate data analysis was applied to identify rice seed cultivars. Spectral data was exacted from hyperspectral images. Along with Partial Least Squares Discriminant Analysis (PLS-DA), Soft Independent Modeling of Class Analogy (SIMCA), K-Nearest Neighbor Algorithm (KNN) and Support Vector Machine (SVM), a novel machine learning algorithm called Random Forest (RF) was applied in this study. Spectra from 1,039 nm to 1,612 nm were used as full spectra to build classification models. PLS-DA and KNN models obtained over 80% classification accuracy, and SIMCA, SVM and RF models obtained 100% classification accuracy in both the calibration and prediction set. Twelve optimal wavelengths were selected by weighted regression coefficients of the PLS-DA model. Based on optimal wavelengths, PLS-DA, KNN, SVM and RF models were built. All optimal wavelengths-based models (except PLS-DA) produced classification rates over 80%. The performances of full spectra-based models were better than optimal wavelengths-based models. The overall results indicated that hyperspectral imaging could be used for rice seed cultivar identification, and RF is an effective classification technique.

Multilayered structures consisting of alternating negative-permittivity and dielectric layers are explored to obtain high-resolution imaging of subwavelength objects. The peaks with the smallest \ky\ (ky is the transverse wave vector) on the transmission curves, which come from the guided modes of the multilayered structures, can not be completely damped by material loss. This makes the amplitudes of the evanescent waves around these peaks inappropriate after transmitted through the imaging structures, and the imaging quality is not good. To solve such a problem, the permittivity of the dielectric layers is appropriately chosen to make these sharp peaks merge with their neighboring peaks, whose corresponding guiding modes in the multilayered structure are cutoff. Wide flat upheavals are then generated on the transmission curves so that evanescent waves in a large range are transmitted through the structures with appropriate amplitudes. In addition, it is found that the sharp peaks with the smallest \ky\ can be eliminated by adding appropriate coating layers and wide flat upheavals can also be obtained.

Liu X.,Zhejiang University | Lu J.,Jiangnan University
Automatica | Year: 2010

This paper studies modeling and identification problems for multi-input multirate systems with colored noises. The state-space models are derived for the systems with different input updating periods and furthermore the corresponding transfer functions are obtained. To solve the difficulty of identification models with unmeasurable noises terms, the least squares based iterative algorithm is presented by replacing the unmeasurable variables with their iterative estimates. Finally, the simulation results indicate that the proposed iterative algorithm has advantages over the recursive algorithms. © 2010 Elsevier Ltd. All rights reserved.

Dong S.,Zhejiang University
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2010

This paper elaborates the development of spatial structure in our country. Because the forms and types are colorful and incessantly innovating, it is necessary to divide spatial structure by component elements. After the 21st century, the development of our nation's spatial structure comes into a new period that the application range and fields for spatial structure extend continuously. Besides the large-span public buildings such as gymnasiums and airports, there are extensive and innovative applications including large-scale railway stations, stations awning without column, bridges and high-rise buildings for spatial structure. About the international cooperation, it is suggested to have an open mind and optimistic view towards the fact that that architecture scheme for our nation's spatial structures are frequently led by foreign companies. China is already a country with a great deal of the top of the world spatial structures, thus it is our responsibility to strive to create even better and advanced spatial structures. Some issues which we should pay more attention are pointed out.

Yao M.,Zhejiang University | Yao M.,University of Miami | Toselli I.,University of Miami | Korotkova O.,University of Miami
Optics Express | Year: 2014

The effects of anisotropic, non-Kolmogorov turbulence on propagating stochastic electromagnetic beam-like fields are discussed for the first time. The atmosphere of interest can be found above the boundary layer, at high (more than 2 km above the ground) altitudes where the energy distribution among the turbulent eddies might not satisfy the classic assumption represented by the famous 11/3 Kolmogorov's power law, and the anisotropy in the direction orthogonal to the Earth surface is possibly present. Our analysis focuses on the classic electromagnetic Gaussian Schell-model beams but can either be readily reduced to scalar and/or coherent beams or generalized to other beam classes. In particular, we explore the effects of the anisotropic parameter on the spectral density, the spectral degree of coherence and on the spectral degree of polarization of the beam. © 2014 Optical Society of America

Xia J.,Zhejiang University | Li L.-Y.,University of Plymouth
Construction and Building Materials | Year: 2013

This paper presents a numerical investigation on the penetration of chloride ions in a saturated cement paste with considering the interactions between different ionic species in pore solution. The work is performed by solving the equations of mass conservation of individual ionic species with electrostatic coupling of ions in a multi-component pore electrolyte solution. Unlike most of existing work where the electrostatic potential was determined based on the assumption of electro-neutrality, the present work uses the Poisson's equation relating the spatial variation in the electric field to the charge distribution to determine the electrostatic potential. As numerical examples, chloride penetrations in saturated cement pastes of different initial concentrations are simulated. The results show that chloride concentration profiles are significantly different in the cement pastes of different initial concentrations. The dependence of chloride penetration on the initial composition of pore solution may explain why the experimentally obtained chloride diffusion coefficients published in literature varying from 10 -12 to 10-10 m2/s. © 2012 Elsevier Ltd. All rights reserved.

Chen Q.,Zhejiang University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

The superfluid transition temperature T c of a unitary Fermi gas on a three-dimensional isotropic lattice with an attractive on-site interaction is investigated as a function of density n, from half filling down to 5×10 -7 per unit cell, using a pairing fluctuation theory. We show that except at very low densities (n1 /3<0.2), where T c/E F is linear in n1 /3, T c/E F exhibits a significant higher-order nonlinear dependence on n1 /3. This calls for extra caution against possible significant error in the zero-density-limit value of T c/E F from typical quantum Monte Carlo (QMC) simulations, obtained by linearly extrapolating data points at intermediate and high densities. Our result, T c/E F=0.256, at the n=0 limit, is close to, and should be compared with, the maximum T c/E F near the Bose-Einstein condensation regime obtained from QMC calculations. © 2012 American Physical Society.

Gan Y.,Zhejiang University | Chen J.K.,University of Missouri
Optics Letters | Year: 2012

Ultrafast laser-induced melting in a gold thin film is simulated by an integrated continuum-atomistic method with the extended Drude model for dynamic optical properties. The local order parameter of atoms is used to identify solid and liquid regions. It is shown that the film is superheated in the early nonequilibrium stage and the melted region grows very quickly with a very high rate of melting up to ̃13; 300 m/s. It is also found that the continuum approach could significantly underestimate the ultrafast phase-change response, and temperaturedependent optical properties should be considered in atomic-level modeling for ultrafast laser heating. © 2012 Optical Society of America.

Lu Q.,Zhejiang University | Lu Q.,Nanyang Technological University | Low B.K.,Nanyang Technological University
Computers and Geotechnics | Year: 2011

Probabilistic analysis of underground rock excavations is performed using response surface method and SORM, in which the quadratic polynomial with cross terms is used to approximate the implicit limit state surface at the design point. The response surface is found using an iterative algorithm and the probability of failure is evaluated using the first-order and the second-order reliability method (FORM/SORM). Independent standard normal variables in U-space are chosen as basic random variables and transformed into correlated non-normal variables in the original space of random variables for constructing the response surface. The proposed method is first illustrated for a circular tunnel with analytical solutions considering Mohr-Coulomb (M-C) and Hoek-Brown (H-B) yield criteria separately. The failure probability with respect to the plastic zone criterion and the tunnel convergence criterion are estimated from FORM/SORM and compared to those obtained from Monte Carlo Simulations. The results show that the support pressure has great influence on the failure probability of the two failure modes. For the M-C model, the hypothesis of uncorrelated friction angle and cohesion will generate higher non-performance probability in comparison to the case of negatively correlated shear strength parameters. Reliability analyses involving non-normal distributions are also investigated. Finally, an example of a horseshoe-shaped highway tunnel is presented to illustrate the feasibility and validity of the proposed method for practical applications where numerical procedures are needed to calculate the performance function values. © 2011 Elsevier Ltd.

Cleall P.J.,University of Cardiff | Li Y.-C.,Zhejiang University
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2011

Analytical solutions are presented for analyzing volatile organic compound (VOC) diffusion through intact composite landfill liners for two scenarios with boundary conditions at the base of either a VOC concentration of zero or a VOC mass flux of zero. A time-dependent concentration top boundary condition is included in the presented analytical solutions to model typical variations of VOC concentration in the leachate over time. The presented solutions are verified against alternative numerical solutions and applied to analyze dichloromethane diffusion through a composite liner. The analytical solutions are found to provide useful predictions of VOC concentration and mass flux for the design of composite liners. VOC concentrations and fluxes at the base of the composite liner at 30 years predicted by consideration of representative transient variation in leachate concentration, for an example problem, are nearly half of those when a constant leachate concentration assumed. © 2011 American Society of Civil Engineers.

Ye H.,Zhejiang University | Yu J.,CAS Institute of Semiconductors
Science and Technology of Advanced Materials | Year: 2014

With the rapid development of on-chip optical interconnects and optical computing in the past decade, silicon-based integrated devices for monolithic and hybrid optoelectronic integration have attracted wide attention. Due to its narrow pseudo-direct gap behavior and compatibility with Si technology, epitaxial Ge-on-Si has become a significant material for optoelectronic device applications. In this paper, we describe recent research progress on heteroepitaxy of Ge flat films and self-assembled Ge quantum dots on Si. For film growth, methods of strain modification and lattice mismatch relief are summarized, while for dot growth, key process parameters and their effects on the dot density, dot morphology and dot position are reviewed. The results indicate that epitaxial Ge-on-Si materials will play a bigger role in silicon photonics. © 2014 National Institute for Materials Science.

Chen W.-Q.,Zhejiang University
Journal of Zhejiang University: Science A | Year: 2014

Continuum mechanics, just as the name implies, deals with the mechanics problems of all continua, whose physical (or mechanical) properties are assumed to vary continuously in the spaces they occupy. Continuum mechanics may be seen as the symbol of modern mechanics, which differs greatly from current physics, the two often being mixed up by people and even scientists. In this short paper, I will first try to give an illustration on the differences between (modern) mechanics and physics, in my personal view, and then focus on some important current research activities in continuum mechanics, attempting to identify its path to the near future. We can see that continuum mechanics, while having a dominating impact on engineering design in the 20th century, also plays a pivotal role in modern science, and is much closer to physics, chemistry, biology, etc. than ever before. © 2014 Zhejiang University and Springer-Verlag Berlin Heidelberg.

Dai D.,Zhejiang University | Dai D.,University of California at Santa Barbara | Tang Y.,University of California at Santa Barbara | Bowers J.E.,University of California at Santa Barbara
Optics Express | Year: 2012

The mode conversion in tapered submicron silicon ridge optical waveguides is investigated theoretically and experimentally. Two types of optical waveguide tapers are considered in this paper. One is a regular lateral taper for which the waveguide width varies while the etching depth is kept the same. The other is a so-called "bi-level" taper, which includes two layers of lateral tapers. Mode conversion between the TM fundamental mode and higher-order TE modes is observed in tapered submicron siliconon- insulator ridge optical waveguides due to the mode hybridization resulting from the asymmetry of the cross section. Such a mode conversion could have a very high efficiency (close to 100%) when the taper is designed appropriately. This enables some applications e.g. polarizer, polarization splitting/rotation, etc. It is also shown that this kind of mode conversion could be depressed by carefully choosing the taper parameters (like the taper width, the etching depth, etc), which is important for the applications when low-loss propagation for the TM fundamental mode is needed. ©2012 Optical Society of America.

Lou F.,KTH Royal Institute of Technology | Dai D.,Zhejiang University | Wosinski L.,KTH Royal Institute of Technology
Optics Letters | Year: 2012

An ultracompact polarization beam splitter (PBS) based on a dielectric-hybrid plasmonic-dielectric coupler is proposed. The device utilizes the polarization-dependent nature of hybrid plasmonic waveguides. By choosing proper waveguide parameters, a 2 × 5.1 μm2 PBS (including S-bends) with extinction ratios over 15 dB and insertion losses below 1.5 dB in the full C-band should be achievable. The effect of fabrication errors is also investigated. © 2012 Optical Society of America.

The neuropeptides corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) are crucially involved in the pathogenesis of depression. The close correlation between the etiology of depression and dysregulation of the stress responses is based upon a hyperactivity of the hypothalamo-pituitary-adrenal (HPA) axis. CRH neurons in the paraventricular nucleus are the motor of the HPA-axis. Centrally released CRH, AVP, and increased levels of cortisol all contribute to the signs and symptoms of depression. Single-nucleotide polymorphisms in the CRH and AVP receptor genes are associated with the risk for depression. Activation of the HPA-axis is generally regarded to be the final common pathway of the pathogenesis of depression. Sex hormones are crucially involved in the regulation of CRH gene expression. The decreased activity of the biological clock, the suprachiasmatic nucleus, as indicated by its lower AVP expression, is the basis for the disturbed rhythms in depression. Both similarities and differences are found in the activity changes in the CRH and AVP systems in depressive disorders and depression in Alzheimer's disease. Copyright 2010 Elsevier Inc. All rights reserved.

Wu D.,National University of Ireland | Sun D.-W.,National University of Ireland | He Y.,Zhejiang University
Innovative Food Science and Emerging Technologies | Year: 2012

This study was carried out for rapid and non-invasive measurement of color distribution in salmon fillet using hyperspectral imaging in long-wave near infrared spectral range (LW-NIR). Successive projections algorithm (SPA) was used to select effective wavelengths. Instead of selecting different sets of effective wavelengths for each color component respectively, instrumental effective wavelengths (IEWs) were identified for the prediction of all three color components, leading to reducing the number of band-pass filters for designing the multispectral imaging system. Meanwhile, predictive effective wavelengths (PEW) were further chosen from IEW to optimize calibration models. The final prediction models were considered as the multiple linear regression (MLR) models with PEW, which resulted in correlation coefficients (r C) of 0.876, 0.744, and 0.803 for L*, a*, and b*, respectively. Finally, the visualization of color distribution in salmon fillets was achieved. The results demonstrated that LW-NIR hyperspectral imaging is a potential technique to quantitatively measure color distribution of salmon fillet in a rapid and non-invasive way. Industrial relevance: This study was conducted to evaluate the feasibility of a hyperspectral imaging system in the LW-NIR spectral region (964 to 1631 nm) for rapid measurement of color in intact salmon fillets. On the basis of the results and accompanying illustrations presented in this work, the study demonstrated the ability of the method based on LW-NIR hyperspectral imaging to measure color distribution of salmon fillets. This method was a rapid, contact-free, and consistent evaluation, and can be used as a reliable and rapid alternative to traditional colorimeter for measuring color of salmon fillet for the food industry. © 2012 Elsevier Ltd.

Ye X.,Zhejiang University
IEEE Transactions on Automatic Control | Year: 2011

In this technical note, we propose a decentralized adaptive output-feedback stabilizer for a class of large-scale nonlinear time-delay systems without a priori knowledge of subsystem high-frequency-gain signs. The time delays can be in the outputs of subsystems and in the interconnections among subsystems. Global asymptotic stabilization results have been proved and a simulation example is given. The note enlarges the class of large-scale nonlinear systems for which global decentralized adaptive stabilizer can be designed. © 2006 IEEE.

He Y.,Zhejiang Normal University | Zhou W.,Center for Neutron Research | Zhou W.,University of Maryland University College | Qian G.,Zhejiang University | Chen B.,University of Texas at San Antonio
Chemical Society Reviews | Year: 2014

Natural gas (NG), whose main component is methane, is an attractive fuel for vehicular applications. Realization of safe, cheap and convenient means and materials for high-capacity methane storage can significantly facilitate the implementation of natural gas fuelled vehicles. The physisorption based process involving porous materials offers an efficient storage methodology and the emerging porous metal-organic frameworks have been explored as potential candidates because of their extraordinarily high porosities, tunable pore/cage sizes and easily immobilized functional sites. In this view, we provide an overview of the current status of metal-organic frameworks for methane storage. This journal is © the Partner Organisations 2014.

Yang G.L.,Zhejiang University
The International journal of oral & maxillofacial implants | Year: 2012

This study investigated the effects of a strontium-substituted nanohydroxyapatite (Sr-HA) coating, deposited onto porous implant surfaces using an electrochemical process, on implant osseointegration in a rabbit model. The surfaces were analyzed by field-emission scanning electron microscopy, x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), a portable surface roughness tester, and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Thirty implants (half HA-coated and half Sr-HA-coated) were inserted into femurs of 15 rabbits. After 2, 4, and 8 weeks, the femurs were retrieved and prepared for histomorphometric evaluation. Microscopic examination showed a surface topography of rodlike crystals on both surfaces. XRD and FT-IR showed that the phase of the deposits was HA. No differences were found in surface roughness between the two groups. ICP-AES showed that the Sr/(Ca+Sr) molar ratio of Sr-HA coating was 10.1 mol%. Histologic observation showed that new bone appeared on both surfaces after 2 weeks and became mature after 8 weeks. Histomorphometric analysis showed no differences between the two groups in bone-to-implant contact at 2 weeks or in bone area within all threads at 2 and 4 weeks. The Sr-HA coated group had significantly higher bone-to-implant contact at 4 and 8 weeks. Significant differences were also found in bone area at 8 weeks. The present study showed that this Sr-HA coating, deposited using an electrochemical process, has the potential to enhance implant osseointegration.

Niu Z.,Virginia Polytechnic Institute and State University | Huang F.,Zhejiang University | Gibson H.W.,Virginia Polytechnic Institute and State University
Journal of the American Chemical Society | Year: 2011

Two novel bis(m-phenylene)-32-crown-10-based cryptands, one bearing covalent linkages and the other metal-complex linkages, were designed and prepared. By self-assembly of these biscryptands, which can be viewed as AA monomers, and a bisparaquat, which can be viewed as a BB monomer, AA-BB-type linear supramolecular polymers with relatively high molecular weights were successfully prepared. © 2011 American Chemical Society.

Wei Y.,Zhejiang University | Zhang Z.,Tongji University
Land Use Policy | Year: 2012

The fragmentation of construction land due to decentralised urban development, disorderly mixed land use, and large-scale transportation infrastructure poses a threat to urban integrity. There is a need to quantify the fragmentation level in a consistent way for inclusion in planning-related decisions. In the context of China's urban sprawl, this study develops a quantitative and intuitive index approach that planners can use to analyse multiple fragmentation features of construction land within urban areas. The approach can be used in planning policy reviews for timely land-use assessment and can be integrated into urban planning processes for developing strategic land-use scenarios. The method was applied in Shunde, a typical urban area in southern China, and construction-land fragmentation and its impacts on environmental quality were analysed. The results show that the entire built-up area in Shunde displays a high level of fragmentation. Patches of industrial and rural residence have been identified specifically higher fragmentation level. The shortage of available construction land makes land consolidation within built-up areas very important in planning Shunde's future development. Moreover, the land shortage requires the progressive reduction of construction land fragmentation. The results of the study also indicate that although land fragmentation has been affected by transportation infrastructure and the existence of rivers and hills in this region, decentralised decisions from hierarchical local governance regimes have greatly exacerbated this situation. Shunde provides examples of typical land-use problems associated with quasi-urbanised regions in China; construction-land fragmentation is a greater determinant for the sustainable development of urban and rural areas than construction-land growth. © 2011 Elsevier Ltd.

Effects of 1% or 0.5% chitosan (CHI), 10% or 5% aqueous extract of ginger, onion and garlic (GOG) and their composite solutions (1% CHI + 10% GOG, 0.5% CHI + 5% GOG) on quality and shelf life of stewed-pork were evaluated. Microbiological (total bacterial count), chemical (pH, total volatile basic nitrogen (TVB-N), peroxide value (POV), 2-thiobarbituric acid (TBA)) and sensory characteristics were analysed periodically during refrigerated storage at 4 °C for 12 days. CHI and/or GOG treatments retarded the increases in pH, TVB-N, POV, TBA and total bacterial count. CHI showed better antibacteria but weaker antioxidation than GOG. Composite treatment had possible synergistic effect while the high concentration of composite solution (Mix1) had adverse effect on odour and overall acceptance. Mix2, the diluted solution of Mix1, could be a natural promising preservative for the stewed-pork considering the comprehensive effects of antioxidation, antibacteria and sensory quality, which could extend the shelf life for about 5-6 days. © 2013 Elsevier Ltd. All rights reserved.

Lin X.,University Pierre and Marie Curie | Lin X.,Zhejiang University | Zhu Z.,University Pierre and Marie Curie | Fauque B.,University Pierre and Marie Curie | Behnia K.,University Pierre and Marie Curie
Physical Review X | Year: 2013

The origin of superconductivity in bulk SrTiO3 is a mystery since the nonmonotonous variation of the critical transition with carrier concentration defies the expectations of the crudest version of the BCS theory. Here, employing the Nernst effect, an extremely sensitive probe of tiny bulk Fermi surfaces, we show that, down to concentrations as low as 5:5 × 1017 cm-3, the system has both a sharp Fermi surface and a superconducting ground state. The most dilute superconductor currently known therefore has a metallic normal state with a Fermi energy as little as 1.1 meV on top of a band gap as large as 3 eV. The occurrence of a superconducting instability in an extremely small, single-component, and barely anisotropic Fermi surface implies strong constraints for the identification of the pairing mechanism. © Published by the American Physical Society.

Cai J.,Zhejiang GongShang University | Zheng P.,Zhejiang University
Bioresource Technology | Year: 2013

Two-chamber microbial fuel cells (MFCs) were operated to remove sulfide and nitrate simultaneously using activated sludge in this study. Compared with control experiment, the MFC showed its ability to remove nitrate and sulfide simultaneously and generate electricity. When the external resistance was 1000Ω, the initial concentrations of sulfide and nitrate were about 60 and 10.5mgL-1, respectively, maximum current density of the MFC was 138.31mAm-2. In the end of a typical cycle, it decreased to 12.20mAm-2. The main end products were nitrogen and sulfate. The microorganisms attached to the anode electrode had electrochemical activity, and the transfer mechanism of electron in MFC was different from that in control MFC. © 2012 Elsevier Ltd.

Jin H.X.,Zhejiang University | Chen H.Y.,Henan University of Urban Construction
Journal of Chemical and Engineering Data | Year: 2012

Densities for 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF 4)-glucose-water solutions were determined at 298.15 K. The measured densities were used to calculate the apparent molar volumes of glucose (V Φ,S) and [Bmim]BF 4 (V Φ,IL) in the studied solutions. Infinite dilution apparent molar volumes, V Φ,S ∞ and V Φ,IL ∞, have been evaluated, together with the standard transfer volumes of the sucrose (Δ tV S ∞) from water to aqueous solutions of [Bmim]BF 4 and those of [Bmim]BF 4 (Δ tV IL ∞) from water to aqueous glucose solution. It was shown that the Δ tV S ∞ and Δ tV IL ∞ values are positive and increase with increasing molalities of [Bmim]BF 4 and glucose, respectively, and the values of V Φ,S ∞ have the order of glucose < sucrose. The volumetric interaction parameters for [Bmim]BF 4-glucose pairs in water were also obtained and interpreted by the structural interactions model. © 2012 American Chemical Society.

Wu J.,Zhejiang University | Gu M.,Swinburne University of Technology
Journal of Biomedical Optics | Year: 2011

Here we introduce the existing fabrication techniques, detection methods, and related techniques for microfluidic sensing, with an emphasis on the detection techniques. A general survey and comparison of the fabrication techniques were given, including prototyping (hot embossing, inject molding, and soft lithography) and direct fabrication (laser micromachining, photolithography, lithography, and x-ray lithography) techniques. This is followed by an in-depth look at detection techniques: Optical, electrochemical, mass spectrometry, as well as nuclear magnetic resonance spectroscopy-based sensing approaches and related techniques. In the end, we highlight several of the most important issues for future work on microfluidic sensing. This article aims at providing a tutorial review with both introductory materials and inspiring information on microfluidic fabrication and sensing for nonspecialists. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Lin Z.,Zhejiang University | Liang C.,Oak Ridge National Laboratory
Journal of Materials Chemistry A | Year: 2015

Lithium-sulfur (Li-S) batteries supply a theoretical specific energy 5 times higher than that of lithium-ion batteries (2500 vs. ∼500 W h kg-1). However, the insulating properties and polysulfide shuttle effects of the sulfur cathode and safety concerns of the lithium anode in liquid electrolytes are still key limitations to practical use of traditional Li-S batteries. In this review, we start with a brief discussion on fundamentals of Li-S batteries and key challenges associated with conventional liquid cells. We then introduce the most recent progress in liquid systems, including sulfur positive electrodes, lithium negative electrodes, and electrolytes and binders. We discuss the significance of investigating electrode reaction mechanisms in liquid cells using in situ techniques to monitor the compositional and morphological changes. We also discuss the importance of this game-changing shift, moving from traditional liquid cells to recently developed solid cells, with positive advances in both solid electrolytes and electrode materials. Finally, the opportunities and perspectives for future research on Li-S batteries are presented. © The Royal Society of Chemistry 2015.

Homeobox D10 (HoxD10 ) gene plays a critical role in cell differentiation and morphogenesis during development. However, the function of HoxD10 in tumor progression remains largely unknown. We demonstrate that the expression of HoxD10 is commonly downregulated in gastric cancer tissues (n = 33) and cell lines (n = 8) relative to normal stomach tissues. Functionally, reexpression of HoxD10 results in significant inhibition of cell survival, induction of cell apoptosis, and impairment of cell migration and invasion. Moreover, ectopic expression of HoxD10 suppresses gastric tumor growth in a mouse xenograft model. To identify target candidates of HoxD10, we performed cDNA microarray and showed that HoxD10 regulates multiple downstream genes including IGFBP3. Reintroduction of HoxD10 transcriptionally upregulates IGFBP3, activates caspase 3 and caspase 8, and subsequently induces cell apoptosis. Methylation specific PCR revealed that HoxD10 promoter DNA was hypermethylated in gastric cancer cell lines. Additionally, 5-aza demethylation treatment could transiently reactivate the expression of HoxD10 in gastric cancer cells. HoxD10 promoter methylation frequently was detected in gastric cancer tissues obtained from endoscopic biopsies (85.7%, 24/28) and surgically resected samples (82.6%, 57/69). Intestinal metaplasia tissues showed a 60% methylation rate (18/30), but no detectable methylation in normal stomach tissues (0%, 0/10). Taken together, our results suggest that HoxD10 functions as a candidate tumor suppressor in gastric cancer, which is inactivated through promoter hypermethylation.

Zhang L.,Georgia Institute of Technology | Zhang L.,Zhejiang University | Xia Y.,Georgia Institute of Technology
Advanced Materials | Year: 2014

Recent progress in facet-controlled syntheses has started to produce nanocrystals with great promise as the next-generation catalysts for a variety of applications. To move from academic studies to industrial applications, however, one has to address the issue of scaling up a synthesis that has been commonly conducted in a batch format. There are two opposite approaches to scaling up the production of colloidal nanocrystals: increasing and decreasing the reaction volume. Contrary to conventional wisdom, continuous flow synthesis based on droplets is expected to provide a more practical platform for scaling up the synthesis. Here we highlight recent progress in using droplet reactors for the synthesis of colloidal noble-metal nanocrystals with controlled sizes and shapes, with an aim towards high-volume production. Most people probably would scale up the production of colloidal nanocrystals by increasing the reaction volume. Here we demonstrate that decreasing the reaction volume with the use of a continuous flow of droplet reactors will be a more practical approach. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhu L.Y.,Zhejiang University
Developmental and comparative immunology | Year: 2013

Fish is considered to be an important model in comparative immunology studies because it is a representative population of lower vertebrates serving as an essential link to early vertebrate evolution. Fish immune-relevant genes have received considerable attention due to its role in improving understanding of both fish immunology and the evolution of immune systems. In this review, we discuss the current understanding of teleost immune-relevant genes for both innate and adaptive immunity, including pattern recognition receptors, antimicrobial peptides, complement molecules, lectins, interferons and signaling factors, inflammatory cytokines, chemokines, adaptive immunity relevant cytokines and negative regulators, major histocompatibility complexes, immunoglobulins, and costimulatory molecules. The implications of these factors on the evolutionary history of immune systems were discussed and a perspective outline of innate and adaptive immunity of teleost fish was described. This review may provide clues on the evolution of the essential defense system in vertebrates. Copyright © 2012 Elsevier Ltd. All rights reserved.

Li D.,Zhejiang University
Journal of the Science of Food and Agriculture | Year: 2014

A vegetarian diet generally includes plenty of vegetables and fruits, which are rich in phytochemicals, antioxidants, fiber, magnesium, vitamins C and E, Fe3+, folic acid and n-6 polyunsaturated fatty acid (PUFA), and is low in cholesterol, total fat and saturated fatty acid, sodium, Fe2+, zinc, vitamin A, B12 and D, and especially n-3 PUFA. Mortality from all-cause, ischemic heart disease, and circulatory and cerebrovascular diseases was significantly lower in vegetarians than in omnivorous populations. Compared with omnivores, the incidence of cancer and type 2 diabetes was also significantly lower in vegetarians. However, vegetarians have a number of increased risk factors for non-communicable diseases such as increased plasma homocysteine, mean platelet volume and platelet aggregability compared with omnivores, which are associated with low intake of vitamin B12 and n-3 PUFA. Based on the present data, it would seem appropriate for vegetarians to carefully design their diet, specifically focusing on increasing their intake of vitamin B12 and n-3 PUFA to further reduce already low mortality and morbidity from non-communicable diseases. © 2013 Society of Chemical Industry.

Ma Q.,Zhejiang University
Critical reviews in food science and nutrition | Year: 2014

Diabetic retinopathy is a common condition that occurs in patients with diabetes with long-standing hyperglycemia that is characterized by inappropriate angiogenesis. This pathological angiogenesis could be a sort of physiological proliferative response to injury by the endothelium. Recent studies suggested that reactive oxygen species (ROS) play a significant role in this angiogenesis. Vascular endothelial growth factor (VEGF) is a potent angiogenic growth factor that plays a significant role in diabetic retinopathy. The interaction between VEGF and ROS, and theirs in turn with pro- and anti-inflammatory cytokines and anti-inflammatory bioactive lipid molecules such as lipoxins, resolvins, protectins, and maresins is particularly relevant to understand the pathophysiology of diabetic retinopathy and develop future therapeutic interventions.

Huang T.,Zhejiang University
The British journal of nutrition | Year: 2013

The association of plasma phospholipid (PL) fatty acid composition with plasma homocysteine (Hcy) in Chinese vegetarians is not understood. The main aim of the present study was to investigate the plasma PL fatty acid status, and its association with plasma Hcy in Chinese vegetarians and omnivores. A total of 103 male vegetarians and 128 male omnivores were recruited in Linyin Temple, Hangzhou. Plasma Hcy and PL fatty acid concentrations were determined by standard methods. Compared with omnivores, plasma PL n-3 PUFA (P< 0·001), 22 : 6n-3 (P< 0·001), 22 : 5n-6 (P= 0·021), 22 : 2n-6 (P< 0·001) and SFA (P= 0·017) were significantly lower, while plasma PL n-6 PUFA (P= 0·007) and total PUFA (P< 0·001) were significantly higher in vegetarians. The prevalence of hyperhomocysteinaemia (HHcy) in vegetarians (26·47 %) was significantly higher than that in omnivores (13·28 %). In vegetarians, plasma PL 22 : 6n-3 (r - 0·257, P= 0·046) was significantly negatively associated with plasma Hcy. In omnivores, plasma PL 18 : 1n-7 (r 0·237, P= 0·030) was significantly positively associated with plasma Hcy. Plasma PL 22 : 6n-3 (r - 0·217, P= 0·048) was negatively associated with plasma Hcy in omnivores. Plasma PL SFA were positively associated with the prevalence of HHcy. It would seem appropriate for vegetarians to increase their dietary n-3 PUFA and decrease dietary SFA, and thus reduce the risk of HHcy.

Chen L.,Huaqiao University | Zhu W.,Zhejiang University
Probabilistic Engineering Mechanics | Year: 2011

The first passage failure of single-degree-of-freedom (SDOF) nonlinear oscillator with lightly fractional derivative damping under real noise excitations is investigated in this paper. First, the system state is approximately represented by one-dimensional time-homogeneous diffusive Markov process of amplitude through stochastic averaging. Then, the backward Kolmogorov equation governing the conditional reliability function and the Pontryagin equation governing the conditional mean of first passage time are established from the averaged It equation for Hamiltonian. The conditional reliability function, the conditional probability density and mean of the first passage time are obtained by solving these equations together with suitable initial condition and boundary conditions. Finally, two examples are worked out in detail and the analytical solutions are checked by those from the Monte Carlo simulation of original systems. © 2010 Elsevier Ltd. All rights reserved.

A vertical multimode waveguide enabling micro-bends is proposed for mode-multiplexed optical interconnect links. The multimode waveguide is designed to be singlemode in the lateral direction and support higher-order modes in the vertical direction. The characteristic analysis for an SOI (silicon-on-insulator)-based vertical multimode waveguide with a ∼0.3μm × ∼1.5μm cross section is given as an example. The theoretical pure bending loss is negligible for all the lowest eight modes when the bending radius is even less than 5μm. When light goes through the structure consisting of a straight section connected with a bent section, it is found that some inter-mode crosstalk is caused by the significant mode hybridization happening in the sharply bent multimode waveguide. For the designed SOI-based vertical multimode waveguide, the inter-mode crosstalk is lower than -20dB even when the bending radius is chosen as small as R = 10μm, which is one order smaller than that for the traditional lateral multimode waveguide (whose minimal bending radius is about 130μm). The intermode crosstalk can be even reduced to -30dB when choosing R = 30μm. Such a multimode optical waveguide microbend with low inter-mode crosstalk is promising for realizing compact mode-multiplexing links. ©2014 Optical Society of America

De Barro P.J.,CSIRO | Liu S.-S.,Zhejiang University | Boykin L.M.,Lincoln University at Christchurch | Dinsdale A.B.,CSIRO | Dinsdale A.B.,University of Queensland
Annual Review of Entomology | Year: 2011

Bemisia tabaci has long been considered a complex species. It rose to global prominence in the 1980s owing to the global invasion by the commonly named B biotype. Since then, the concomitant eruption of a group of plant viruses known as begomoviruses has created considerable management problems in many countries. However, an enduring set of questions remains: Is B. tabaci a complex species or a species complex, what are Bemisia biotypes, and how did all the genetic variability arise? This review considers these issues and concludes that there is now sufficient evidence to state that B. tabaci is not made up of biotypes and that the use of biotype in this context is erroneous and misleading. Instead, B. tabaci is a complex of 11 well-defined high-level groups containing at least 24 morphologically indistinguishable species. © 2011 by Annual Reviews. All rights reserved.

Wang X.,Zhejiang Agriculture And forestry University | Zhao D.,Zhejiang University
Optics Letters | Year: 2013

We propose a simple amplitude-phase retrieval attack free cryptosystem based on direct attack to phase-truncated Fourier-transform-based encryption using a random amplitude mask (RAM). The RAM that is not saved during the encryption provides extremely high security for the two private keys, and no iterative calculations are involved in the nonlinear encryption process. Lack of enough constraints makes the specific attack based on iterative amplitudephase retrieval algorithms unusable. Numerical simulation results are given for testing the validity and security of the proposed approach. © 2013 Optical Society of America.

Chen W.,Ningbo University | Wang P.,Ningbo University | Yang J.,Zhejiang University
Optics Express | Year: 2013

A mode-(de)multiplexer with low loss and large spectral bandwidth is proposed. The device is designed by utilizing a structure with cascaded asymmetric Y-junctions. By carefully controlling the widths of the wide and narrow arms of the Y-junctions, the fundamental mode of a narrow arm excites the higher-order mode of its stem in the multiplexing case, and a high-order mode of the stem separated from other lower-order modes evolves into the fundamental mode of the narrow arm in the demultiplexing case. As an example, a 1 4 mode-(de)multiplexer is analyzed by using the beam propagation method. Simulation results show the demultiplexed crosstalk is lower than-21.8 dB, under a common spectral bandwidth of 140 nm. The insertion loss is negligible. ©2013 Optical Society of America.

Cao L.,Zhejiang University | Bala G.,Indian Institute of Science | Caldeira K.,Carnegie Institution
Environmental Research Letters | Year: 2012

Recent studies show that fast climate response on time scales of less than a month can have important implications for long-term climate change. In this study, we investigate climate response on the time scale of days to weeks to a step-function quadrupling of atmospheric CO2 and contrast this with the response to a 4% increase in solar irradiance. Our simulations show that significant climate effects occur within days of a stepwise increase in both atmospheric CO2 content and solar irradiance. Over ocean, increased atmospheric CO2 warms the lower troposphere more than the surface, increasing atmospheric stability, moistening the boundary layer, and suppressing evaporation and precipitation. In contrast, over ocean, increased solar irradiance warms the lower troposphere to a much lesser extent, causing a much smaller change in evaporation and precipitation. Over land, both increased CO2 and increased solar irradiance cause rapid surface warming that tends to increase both evaporation and precipitation. However, the physiological effect of increased atmospheric CO2 on plant stomata reduces plant transpiration, drying the boundary layer and decreasing precipitation. This effect does not occur with increased solar irradiance. Therefore, differences in climatic effects from CO2 versus solar forcing are manifested within days after the forcing is imposed. © 2012 IOP Publishing Ltd.

Ma H.,Zhejiang University | He Z.,University of Tokyo | Hotate K.,University of Tokyo
Journal of Lightwave Technology | Year: 2011

Resonator micro optic gyro (RMOG) with a waveguide-type ring resonator is a promising candidate for applications requiring small, light and robust gyros. In optical passive ring resonator gyros, clockwise (CW) and counter clockwise (CCW) lightwaves are phase-modulated at different frequencies to reduce the backscattering induced noise. The effectiveness of this technique, however, is determined by the carrier suppression level. In this paper, the influence of the carrier suppression level on the gyro performance is examined experimentally for an RMOG system with a silica waveguide resonator. In our experiment, carrier suppression is applied onto both the CW and the CCW lightwaves at the same time to achieve higher total suppression. We show that carrier suppression as high as 100 dB can be achieved by optimizing the amplitude of the phase modulation. A bias stability of 0.46°/s in 50 seconds is demonstrated in an RMOG with a silica waveguide ring resonator having a ring length of 7.9 cm. This is the best result reported to date, to the best of our knowledge, for waveguide-type ring resonator gyros of this size. © 2011 IEEE.

Liu T.,Zhejiang University
Mini reviews in medicinal chemistry | Year: 2010

CCR5 (C-C chemokine receptor type 5) is a chemokine receptor that has been identified as a major HIV co-receptor in viral entry and therefore is a highly validated target for the development of new anti-HIV drugs. Here, we discuss the insights gained so far relevant to the development of small-molecule CCR5 inhibitors for the treatment of HIV, and highlight small-molecule CCR5 inhibitors that are currently under preclinical and clinical trials.

Wen W.,Hainan University | Wu J.-M.,Zhejiang University
RSC Advances | Year: 2014

Solution combustion synthesis (SCS) is a worldwide adopted technique to synthesize nanomaterials, especially for oxides, because of its simplicity, energy and time-effectiveness, and low cost. The general difficulty encountered in SCS is the controllability over phases and morphologies of the products, which arises from the inherent rapid and uncontrollable combustion procedure. In this regard, the present work is devoted to review the recent progress on phase- and morphology-controlled SCS in detail. Besides the various metal oxides, SCS is now applicable to fabricate nanomaterials of metal phosphates, metal silicates, metal borates, metal sulfides, metals, and even alloys, through careful selection of solution compositions. Oxides with regular morphologies of flowers, belts, triangles, tubes, wires, and rods can be synthesized by SCS, in the presence of certain templates, or through a self-assembly procedure. The recent progress made on the synthesis of porous materials via SCS is summarized. SCS is also capable of growing metal oxide thin films at low temperatures, enabling the fabrication of low-cost and high-performance electronics on flexible plastic substrates. This journal is © The Royal Society of Chemistry.

Termicin is a defensin-like antimicrobial peptide of termites that has strong antifungal activity. Fifty-six different termicin mRNAs encoding 46 different peptides were amplified and identified from Odontotermes formosanus (Termitidae), a species that inhabits environments with a large variety of microbial fauna. In contrast, only 38 different termicin mRNAs encoding 21 different peptides were amplified and identified from Reticulitermes chinensis (Rhinotermitidae). All mRNAs were amplified by reverse transcript PCR, with primers designed from reported termicin mRNA sequences. All of these genes showed high intraspecific sequence identity and were found to be highly homologous with other reported termicin genes. These two termite species live in different environments; the latter encounters relatively fewer pathogens in its habitat. We conclude that differences in microenvironmental pressure can affect the number of termicin genes expressed in termite species.

Pi X.,Zhejiang University | Delerue C.,CNRS Institute of Electronics, Microelectronics and Nanotechnology
Physical Review Letters | Year: 2013

We present tight-binding calculations in the random-phase approximation of the optical response of Silicon nanocrystals (Si NCs) ideally doped with large concentrations of phosphorus (P) atoms. A collective response of P-induced electrons is demonstrated, leading to localized surface plasmon resonance (LSPR) when a Si NC contains more than ≈10 P atoms. The LSPR energy varies not only with doping concentration but also with NC size due to size-dependent screening by valence electrons. The simple Drude-like behavior is recovered for NC size above 4 nm. Si NCs containing a large number of deep defects in place of hydrogenic impurities do not give rise to LSPR. © 2013 American Physical Society.

To investigate the association between intake of fish and n-3 polyunsaturated fatty acids (n-3 PUFA) and the risk of breast cancer and to evaluate the potential dose-response relation. Meta-analysis and systematic review of prospective cohort studies. PubMed and Embase up to December 2012 and references of retrieved relevant articles. Prospective cohort studies with relative risk and 95% confidence intervals for breast cancer according to fish intake, n-3 PUFA intake, or tissue biomarkers. Twenty six publications, including 20,905 cases of breast cancer and 883,585 participants from 21 independent prospective cohort studies were eligible. Eleven articles (13,323 breast cancer events and 687,770 participants) investigated fish intake, 17 articles investigated marine n-3 PUFA (16,178 breast cancer events and 527,392 participants), and 12 articles investigated alpha linolenic acid (14,284 breast cancer events and 405,592 participants). Marine n-3 PUFA was associated with 14% reduction of risk of breast cancer (relative risk for highest v lowest category 0.86 (95% confidence interval 0.78 to 0.94), I(2)=54), and the relative risk remained similar whether marine n-3 PUFA was measured as dietary intake (0.85, 0.76 to 0.96, I(2)=67%) or as tissue biomarkers (0.86, 0.71 to 1.03, I(2)=8%). Subgroup analyses also indicated that the inverse association between marine n-3 PUFA and risk was more evident in studies that did not adjust for body mass index (BMI) (0.74, 0.64 to 0.86, I(2)=0) than in studies that did adjust for BMI (0.90, 0.80 to 1.01, I(2)=63.2%). Dose-response analysis indicated that risk of breast cancer was reduced by 5% per 0.1g/day (0.95, 0.90 to 1.00, I(2)=52%) or 0.1% energy/day (0.95, 0.90 to 1.00, I(2)=79%) increment of dietary marine n-3 PUFA intake. No significant association was observed for fish intake or exposure to alpha linolenic acid. Higher consumption of dietary marine n-3 PUFA is associated with a lower risk of breast cancer. The associations of fish and alpha linolenic acid intake with risk warrant further investigation of prospective cohort studies. These findings could have public health implications with regard to prevention of breast cancer through dietary and lifestyle interventions.

Li F.,National University of Singapore | Ooi B.C.,National University of Singapore | Ozsu M.T.,University of Waterloo | Wu S.,Zhejiang University
ACM Computing Surveys | Year: 2014

MapReduce is a framework for processing and managing large-scale datasets in a distributed cluster, which has been used for applications such as generating search indexes, document clustering, access log analysis, and various other forms of data analytics. MapReduce adopts a flexible computation model with a simple interface consisting of map and reduce functions whose implementations can be customized by application developers. Since its introduction, a substantial amount of research effort has been directed toward making it more usable and efficient for supporting database-centric operations. In this article, we aim to provide a comprehensive review of a wide range of proposals and systems that focusing fundamentally on the support of distributed data management and processing using the MapReduce framework. © 2014 ACM.

Zhao F.-Q.,University of Vermont | Zhao F.-Q.,Zhejiang University
Journal of Mammary Gland Biology and Neoplasia | Year: 2014

Glucose is the major precursor of lactose, which is synthesized in Golgi vesicles of mammary secretory alveolar epithelial cells during lactation. Glucose is taken up by mammary epithelial cells through a passive, facilitative process, which is driven by the downward glucose concentration gradient across the plasma membrane. This process is mediated by facilitative glucose transporters (GLUTs), of which there are 14 known isoforms. Mammary glands mainly express GLUT1 and GLUT8, and GLUT1 is the predominant isoform with a K m of ~10 mM and transport activity for mannose and galactose in addition to glucose. Mammary glucose transport activity increases dramatically from the virgin state to the lactation state, with a concomitant increase in GLUT expression. The increased GLUT expression during lactogenesis is not stimulated by the accepted lactogenic hormones. New evidence indicates that a possible low oxygen tension resulting from increased metabolic rate and oxygen consumption may play a major role in stimulating glucose uptake and GLUT1 expression in mammary epithelial cells during lactogenesis. In addition to its primary presence on the plasma membrane, GLUT1 is also expressed on the Golgi membrane of mammary epithelial cells and is likely involved in facilitating the uptake of glucose and galactose to the site of lactose synthesis. Because lactose synthesis dictates milk volume, regulation of GLUT expression and trafficking represents potentially fruitful areas for further research in dairy production. In addition, this research will have pathological implications for the treatment of breast cancer because glucose uptake and GLUT expression are up-regulated in breast cancer cells to accommodate the increased glucose need. © 2013 Springer Science+Business Media New York.

Li C.,Zhejiang University | Zheng Q.,University of Electronic Science and Technology of China
Physical Biology | Year: 2010

As is well known, synchronization phenomena are ubiquitous in neuronal systems. Recently a lot of work concerning the synchronization of the neuronal network has been accomplished. In these works, the synapses are usually considered reliable, but experimental results show that, in biological neuronal networks, synapses are usually unreliable. In our previous work, we have studied the synchronization of the neuronal network with unreliable synapses; however, we have not paid attention to the effect of topology on the synchronization of the neuronal network. Several recent studies have found that biological neuronal networks have typical properties of small-world networks, characterized by a short path length and high clustering coefficient. In this work, mainly based on the small-world neuronal network (SWNN) with inhibitory neurons, we study the effect of network topology on the synchronization of the neuronal network with unreliable synapses. Together with the network topology, the effects of the GABAergic reversal potential, time delay and noise are also considered. Interestingly, we found a counter-intuitive phenomenon for the SWNN with specific shortcut adding probability, that is, the less reliable the synapses, the better the synchronization performance of the SWNN. We also consider the effects of both local noise and global noise in this work. It is shown that these two different types of noise have distinct effects on the synchronization: one is negative and the other is positive. © 2010 IOP Publishing Ltd.

Cai L.L.,Zhejiang University
International journal of nanomedicine | Year: 2011

Solid tumors need new blood vessels to feed and nourish them as well as to allow tumor cells to escape into the circulation and lodge in other organs, which is termed "angiogenesis." Some tumor cells within solid tumors can overexpress integrins α(v)β(3) and α(v)β(5), which can specifically recognize the peptide motif Arg-Gly-Asp (RGD). Thus, the targeting of RGD-modified micelles to tumor vasculature is a promising strategy for tumor-targeting treatment. RGD peptide (GSSSGRGDSPA) was coupled to poly(ethylene glycol)-modified stearic acid-grafted chitosan (PEG-CS-SA) micelles via chemical reaction in the presence of N,N'-Disuccinimidyl carbonate. The critical micelle concentration of the polymeric micelles was determined by measuring the fluorescence intensity of pyrene as a fluorescent probe. The micelle size, size distribution, and zeta potential were measured by light scattering and electrophoretic mobility. Doxorubicin (DOX) was chosen as a model anticancer drug to investigate the drug entrapment efficiency, in vitro drug-release profile, and in vitro antitumor activities of drug-loaded RGD-PEG-CS-SA micelles in cells that overexpress integrins (α(ν)β(3) and α(ν)β(5)) and integrin-deficient cells. Using DOX as a model drug, the drug encapsulation efficiency could reach 90%, and the in vitro drug-release profiles suggested that the micelles could be used as a controlled-release carrier for the hydrophobic drug. Qualitative and quantitative analysis of cellular uptake indicated that RGD-modified micelles could significantly increase the DOX concentration in integrin-overexpressing human hepatocellular carcinoma cell line (BEL-7402), but not in human epithelial carcinoma cell line (Hela). The competitive cellular-uptake test showed that the cellular uptake of RGD-modified micelles in BEL-7402 cells was significantly inhibited in the presence of excess free RGD peptides. In vitro cytotoxicity tests demonstrated DOX-loaded RGD-modified micelles could specifically enhance the cytotoxicity against BEL-7402 compared with DOX-loaded PEG-CS-SA and doxorubicin hydrochlorate. This study suggests that RGD-modified PEG-CS-SA micelles are promising drug carriers for integrin-overexpressing tumor active targeting therapy.

Ye S.,Zhejiang University | Li Y.,CAS Shanghai Institute of Materia Medica | Jiang Y.,University of Texas Southwestern Medical Center
Nature Structural and Molecular Biology | Year: 2010

K+ channels are highly selective for K+ over Na +. Here we present several crystal structures of the MthK K + channel pore at up to 1.45-Åresolution. The MthK selectivity filter maintains a conductive conformation even in the absence of K+, allowing the channel to conduct Na+. The high-resolution structures, along with single-channel recordings, allow for an accurate analysis of how K+ competes with Na+ in a conductive selectivity filter. At high K+ concentrations, two K+ ions equivalently occupy the four sites in the selectivity filter, whereas at low K+/high Na+ concentrations, a single K+ ion remains bound in the selectivity filter, preferably at site 1 or site 3. This single K+ binding at low concentration effectively blocks the permeation of Na +, providing a structural basis for the anomalous mole-fraction effect, a key property of multi-ion pores. © 2010 Nature America, Inc. All rights reserved.

Cheng J.,Zhejiang University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The dinuclear title complex, [Mg 2(C 19H 40N 3Si 2) 2C l2(C 4H 8O) 2], lies on a center of inversion. The Mg 2+ ions are bonded to a chelating N,N′-bonded guanidinate anion, a tetra-hydro-furan mol-ecule and two bridging chloride anions. The geometry of the resulting five-coordinated Mg 2+ ion is a very distorted square-based pyramid with the O atom in the apical position. © Jie Cheng 2011.

Chen H.,Zhejiang University | Gottweis H.,Kyung Hee University
Bioethics | Year: 2013

The paper looks in detail at patients that were treated at one of the most discussed companies operating in the field of untried stem cell treatments, Beike Biotech of Shenzhen, China. Our data show that patients who had been treated at Beike Biotech view themselves as proactively pursuing treatment choices that are not available in their home countries. These patients typically come from a broad variety of countries: China, the United Kingdom, the United States, South Africa and Australia. Among the patients we interviewed there seemed to be both an awareness of the general risks involved in such experimental treatments and a readiness to accept those risks weighed against the possible benefits. We interpret this evidence as possibly reflecting the emergence of risk-taking patients as 'consumers' of medical options as well as the drive of patients to seek treatment options in the global arena, rather than being hindered by the ethical and regulatory constraints of their home countries. Further, we found that these patients tend to operate in more or less stable networks and groups in which they interact and cooperate closely and develop opinions and assessments of available treatment options for their ailments. These patients also perform a multiple role as patients, research subjects, and research funders because they are required to pay their way into treatment and research activities. This new social dynamics of patienthood has important implications for the ethical governance of stem cell treatments. © 2011 Blackwell Publishing Ltd.

Wu J.,Massachusetts Institute of Technology | Wu J.,Zhejiang University | Silbey R.J.,Massachusetts Institute of Technology | Cao J.,Massachusetts Institute of Technology
Physical Review Letters | Year: 2013

An asymptotic scaling theory is presented using the conceptual basis of trapping-free subspace (i.e., orthogonal subspace) to establish the generic mechanism of optimal efficiency of excitation energy transfer in light-harvesting systems. A quantum state orthogonal to the trap will exhibit noise-assisted transfer, clarifying the significance of initial preparation. For such an initial state, the efficiency is enhanced in the weak damping limit , and suppressed in the strong damping limit, analogous to Kramers turnover in classical rate theory. An interpolating expression quantitatively describes the trapping time over the entire range of the dissipation strength, and predicts the optimal efficiency at Γopt∼J for homogenous systems. In the presence of static disorder, the scaling law of transfer time with respect to dephasing rate changes from linear to square root, suggesting a weaker dependence on the environment. The prediction of the scaling theory is verified in a symmetric dendrimer system by numerically exact quantum calculations. Though formulated in the context of excitation energy transfer, the analysis and conclusions apply in general to open quantum processes, including electron transfer, fluorescence emission, and heat conduction. © 2013 American Physical Society.

Mobilization of mesenchymal stem cells (MSCs) is a promising strategy for tissue repair and regenerative medicine. The establishment of an appropriate animal model and clarification of the underlying mechanisms are beneficial to develop the mobilization regimens for therapeutic use. In this study, we therefore established a rat MSC mobilization model and investigated the related mechanisms, using continuous hypoxia as the mobilizing stimulus. We found that MSCs could be mobilized into peripheral blood of rats exposed to short-term hypoxia (2 days) and the mobilization efficiency increased in a time-dependent manner (2-14 days). Hypoxia-inducible factor-1α (HIF-1α) was upregulated during hypoxic exposure and was expressed continuously in bone marrow. Inhibition of HIF-1α expression by YC-1 remarkably reduced the number of mobilized MSCs, suggesting that HIF-1α is essential for hypoxia-induced MSC mobilization. Further, we investigated the potential role of HIF-1α target genes, vascular endothelial growth factor (VEGF), and stromal cell-derived factor-1α (SDF-1α). VEGF expression was elevated from day 2 to day 7 of hypoxia, stimulating an increase in bone marrow sinusoidal vessels and possibly facilitating the egress of MSCs. SDF-1α protein levels were increased in the peripheral blood of rats during MSC mobilization and promoted the migration of MSCs under hypoxic conditions in vitro. These results suggest that HIF-1α plays a pivotal role in hypoxia-induced MSC mobilization, possibly acting via its downstream genes VEGF and SDF-1α. These data provide a novel insight into the mechanisms responsible for MSC mobilization and may help in the development of clinically useful therapeutic agents.

Xu J.,CAS Fujian Institute of Research on the Structure of Matter | Dong G.,CAS Fujian Institute of Research on the Structure of Matter | Jin C.,Zhejiang University | Huang M.,CAS Fujian Institute of Research on the Structure of Matter | Guan L.,CAS Fujian Institute of Research on the Structure of Matter
ChemSusChem | Year: 2013

S and N co-doped, few-layered graphene oxide is synthesized by using pyrimidine and thiophene as precursors for the application of the oxygen reduction reaction (ORR). The dual-doped catalyst with pyrrolic/graphitic N-dominant structures exhibits competitive catalytic activity (10.0mA cm -2 kinetic-limiting current density at -0.25V) that is superior to that for mono N-doped carbon nanomaterials. This is because of a synergetic effect of N and S co-doping. Furthermore, the dual-doped catalyst also shows an efficient four-electron-dominant ORR process, which has excellent methanol tolerance and improved durability in comparison to commercial Pt/C catalysts. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lin F.,New York University | Zhang T.,Zhejiang University
Archive for Rational Mechanics and Analysis | Year: 2015

In this paper, we provide a much simplified proof of the main result in Lin and Zhang (Commun Pure Appl Math 67: 531–580, 2014) concerning the global existence and uniqueness of smooth solutions to the Cauchy problem for a three dimensional incompressible complex fluid model under the assumption that the initial data are close to some equilibrium states. Besides the classical energy method, the interpolating inequalities and the algebraic structure of the equations coming from the incompressibility of the fluid are crucial in our arguments. We combine the energy estimates with the L∞ estimates for time slices to deduce the key L1 in time estimates. The latter is responsible for the global in time existence. © 2014, Springer-Verlag Berlin Heidelberg.

Hu W.W.,Zhejiang University
ACS chemical neuroscience | Year: 2012

Histamine is recognized as a neurotransmitter or neuromodulator in the brain, and it plays a major role in the pathogenic progression after cerebral ischemia. Extracellular histamine increases gradually after ischemia, and this may come from histaminergic neurons or mast cells. Histamine alleviates neuronal damage and infarct volume, and it promotes recovery of neurological function after ischemia; the H1, H2, and H3 receptors are all involved. Further studies suggest that histamine alleviates excitotoxicity, suppresses the release of glutamate and dopamine, and inhibits inflammation and glial scar formation. Histamine may also affect cerebral blood flow by targeting to vascular smooth muscle cells, and promote neurogenesis. Moreover, endogenous histamine is an essential mediator in the cerebral ischemic tolerance. Due to its multiple actions, affecting neurons, glia, vascular cells, and inflammatory cells, histamine is likely to be an important target in cerebral ischemia. But due to its low penetration of the blood-brain barrier and its wide actions in the periphery, histamine-related agents, like H3 antagonists and carnosine, show potential for cerebral ischemia therapy. However, important questions about the molecular aspects and pathophysiology of histamine and related agents in cerebral ischemia remain to be answered to form a solid scientific basis for therapeutic application.

Wu J.-Y.,Zhejiang University
Computer Methods in Applied Mechanics and Engineering | Year: 2011

Aiming to provide a justified theoretical ground based on which different enriched finite elements can be systematically compared, we developed in this work a unified framework for modeling cohesive cracks using the variational multiscale method. The kinematics (i.e. coarse and fine scale displacement and strain fields) and statics (i.e. coarse and fine scale equilibrium equations) are thoroughly investigated in both continuum and discrete settings. With respect to the fine scale kinematics and statics adopted in the embedded finite element method (EFEM) and the extended finite element method (XFEM), we mainly discuss four groups of enriched finite elements with non-uniform discontinuity modes, i.e. the kinematically optimal symmetric EFEM and XFEM, as well as, the kinematically and statically optimal non-symmetric EFEM and XFEM. In all these methods, the enrichment parameters can be regarded either as element-wise local or continuous global variables. The enriched finite elements with material/element/node enrichments are then exemplified in an increasing order of their respective capabilities in representing the fine scale kinematics, and the interrelations between them are also discussed. Owing to this unified framework, we are able to clarify some existing points of view related to EFEM and XFEM. It is found that, if the same fine scale statics is used and the same local/global property is assumed for the involved enrichment parameters, XFEM can be regarded as a kinematically enhanced EFEM since it accounts for a more general fine scale kinematics than that (i.e. relative rigid body motions and self-stretching) considered in EFEM. Finally, several simple, but sufficiently representative, numerical examples are presented to show the significance in appropriately reflecting the fine scale kinematics and statics in an enriched finite element for modeling cohesive cracks. © 2011 Elsevier B.V.

Ma E.,Johns Hopkins University | Zhang Z.,Zhejiang University
Nature Materials | Year: 2011

The internal structure of amorphous alloys was initially described as random packing of hard spheres. The internal structure of amorphous alloys was initially described as random packing of hard spheres. Even high-resolution transmission electron microscope (TEM) images, which otherwise are able to resolve lattice fringes in crystals, display only a maze-like pattern with no discernable structure. The subnanometer beam size used by Hirata and colleagues, in contrast, is sufficiently small to address individual polyhedra, and the researchers are consequently able to observe distinct diffraction spots in symmetric patterns that resemble those for single crystals to some extent. The dependence of local structure on alloy composition may now be confirmed experimentally.

Zhang T.,Zhejiang University
Journal of Mathematical Physics | Year: 2011

In this paper, we consider the global existence and uniqueness of the classical (weak) solution for the 2D or 3D compressible Navier-Stokes equations with a density-dependent viscosity coefficient (λ = λ(ρ)). Initial data and solutions are only small in the energy-norm. We also give a description of the large time behavior of the solution. Then, we study the propagation of singularities in solutions. We obtain that if there is a vacuum domain initially, then the vacuum domain will exist for all time, and vanishes as time goes to infinity. © 2011 American Institute of Physics.

Yang X.-L.,Hebei University | Zhang J.-Z.,Zhejiang University | Luo D.-Q.,Hebei University
Natural Product Reports | Year: 2012

Covering: 1991 to November 2011 A growing body of evidence indicates that the Pestalotiopsis genus represents a huge and largely untapped resource of natural products with chemical structures that have been optimized by evolution for biological and ecological relevance. So far, 196 secondary metabolites have been encountered in this genus. This review systematically surveys the taxonomy, biology and chemistry of the Pestalotiopsis genus. It also summarises the biosynthetic relationships and chemical synthesis of metabolites from this genus. There are 184 references This journal is © 2012 The Royal Society of Chemistry.

Ying Z.G.,Zhejiang University
JVC/Journal of Vibration and Control | Year: 2010

A minimax stochastic optimal control strategy for bounded-uncertain stochastic systems is proposed. The minimax dynamical programming equation for an uncertain stochastic control system is firstly derived based on the optimality principle and It differential rule. A new type of bang-bang constraint on the bounded uncertain disturbance is proposed to form a class of minimax stochastic optimal control problems. Then the worst disturbance and minimax optimal control are obtained for the bang-bang-type uncertain system under stochastic excitations. According to this method, the quasi linear control law is obtained for linear stochastic systems with bounded uncertainty and the state-dependent quasi Riccati equation is derived from the minimax dynamical programming equation. Furthermore, a minimax stochastic optimal control strategy for uncertain stochastic quasi Hamiltonian systems is developed based on the stochastic averaging method and minimax dynamical programming equation. The worst disturbance and minimax optimal control for the stochastically averaged system are obtained by the similar procedure. The proposed and developed minimax stochastic optimal control strategies are illustrated with an example of a single-degree-of-freedom uncertain stochastic control system. © 2010 SAGE Publications Los Angeles, London, New Delhi, Singapore.

Bao A.-M.,Zhejiang University | Swaab D.F.,Academy of Arts and science
Neuroscientist | Year: 2010

Sex differences in the brain are reflected in behavior and in the risk for neuropsychiatric disorders. The fetal brain develops in the male direction due to a direct effect of testosterone on the developing neurons, or in the female direction due to the absence of such a testosterone surge. Because sexual differentiation of the genitals takes place earlier in intrauterine life than sexual differentiation of the brain, these two processes can be influenced independently of each other. Gender identity (the conviction of belonging to the male or female gender), sexual orientation (heterosexuality, homosexuality, or bisexuality), pedophilia, sex differences in cognition, and the risks for neuropsychiatric disorders are programmed into our brains during early development. There is no proof that postnatal social environment has any crucial effect on gender identity or sexual orientation. Structural and functional sex differences in brain areas, together with changes in sex hormone levels and their receptors in development and adulthood, are closely related to sex differences in behavior and neuropsychiatric disorders. Knowing that such a relationship exists may help bring about sex-specific therapeutic strategies. © The Author(s) 2010.

Li B.,Zhejiang University
Computational Intelligence and Neuroscience | Year: 2014

Gold price forecasting has been a hot issue in economics recently. In this work, wavelet neural network (WNN) combined with a novel artificial bee colony (ABC) algorithm is proposed for this gold price forecasting issue. In this improved algorithm, the conventional roulette selection strategy is discarded. Besides, the convergence statuses in a previous cycle of iteration are fully utilized as feedback messages to manipulate the searching intensity in a subsequent cycle. Experimental results confirm that this new algorithm converges faster than the conventional ABC when tested on some classical benchmark functions and is effective to improve modeling capacity of WNN regarding the gold price forecasting scheme. © 2014 Bai Li.

Song M.,Zhejiang University
IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics : a publication of the IEEE Systems, Man, and Cybernetics Society | Year: 2010

Eye detection plays an important role in many practical applications. This paper presents a novel two-step scheme for eye detection. The first step models an eye by a newly defined visual-context pattern (VCP), and the second step applies semisupervised boosting for precise detection. VCP describes both the space and appearance relations between an eye region (region of eye) and a reference region (region of reference). The context feature of a VCP is extracted by using the integral image. Aiming to reduce the human labeling efforts, we apply semisupervised boosting, which integrates the context feature and the Haar-like features for precise eye detection. Experimental results on several standard face data sets demonstrate that the proposed approach is effective, robust, and efficient. We finally show that this approach is ready for practical applications.

An exact solution is obtained for multilayered pyroelectric cylindrical (MPC) actuators with weakly conducting interfaces subjected to thermo-electro-mechanical loading. The outer surface of the composite cylindrical actuator is supported by a Winkler-type elastic foundation. At the interface, all the thermal and mechanical quantities as well as the normal electric displacement are assumed to be continuous but the electric potential is discontinuous. The temperature fields are obtained by the transfer matrix method and the piezothermoelastic fields are developed by the state space method combined with the Cayley-Hamilton theorem. Numerical results are presented graphically to show the effects of the elastic foundation, interfacial parameters and heat transfer coefficient on the piezothermoelastic behavior of MPC actuators. © 2014 IOP Publishing Ltd.

Blast crisis (BC) is the final deadly phase of chronic myeloid leukemia (CML), but its molecular basis remains poorly understood. Here, we show that CML BC is regulated by calcium-calmodulin-dependent kinase IIγ (CaMKIIγ). Genetic deletion of CaMKIIγ greatly inhibits disease progression via selectively impairing the self-renewal of leukemia stem cells (LSCs) in mouse models, whereas overexpression of CaMKIIγ has the opposite effects. In human CML, phosphorylated CaMKIIγ abundance is significantly associated with BC. Moreover, CaMKIIγ phosphorylates and reduces the nuclear cyclin-dependent kinase inhibitor p27Kip1, a critical brake that maintains LSC quiescence. These findings suggest that CaMKIIγ might be an important switch for the transition of CML BC and identify a unique mechanism by which CaMKIIγ promotes the self-renewal of LSCs by deceasing nuclear p27Kip1 to wake up dormant LSCs. Therefore, CaMKIIγ may provide a new therapeutic target to treat CML BC.Leukemia advance online publication, 25 March 2016; doi:10.1038/leu.2016.53. © 2016 Macmillan Publishers Limited

Zhang X.,Zhejiang University
Communications in Mathematical Physics | Year: 2011

In this paper, we show that the existence of Sasakian-Einstein metrics is closely related to the properness of corresponding energy functionals. Under the condition of admitting no nontrivial Hamiltonian holomorphic vector field, we prove that the existence of Sasakian-Einstein metric implies a Moser-Trudinger type inequality. At the end of this paper, we also obtain a Miyaoka-Yau type inequality in Sasakian geometry. © 2011 Springer-Verlag.

Saha D.,New Mexico State University | Bao Z.,Zhejiang University | Jia F.,New Mexico State University | Deng S.,New Mexico State University
Environmental Science and Technology | Year: 2010

Adsorption equilibrium and kinetics of CO2, CH4, N2O, and N2 on two newly discovered adsorbents, metal-organic frameworks MOF-5 and MOF-177 and one traditional adsorbent, zeolite 5A were determined to assess their efficacy for CO2, CH 4, and N2O removal from air and separation of CO 2 from CH4 in pressure swing adsorption processes. Adsorption equilibrium and kinetics data for CO2, CH4, N2O, and N2 on all three adsorbents were measured volumetrically at 298K and gas pressures up to 800 Torr. Adsorption equilibrium capacities of CO2 and CH4 on all three adsorbents were determined gravimetrically at 298 K and elevated pressures (14 bar for CO 2 and 100 bar for CH4). The Henry's law and Langmuir adsorption equilibrium models were applied to correlate the adsorption isotherms, and a classical micropore diffusion model was used to analyze the adsorption kinetic data. The adsorption equilibrium selectivity was calculated from the ratio of Henry's constants, and the adsorbent selection parameter for pressure swing adsorption processes were determined by combining the equilibrium selectivity and working capacity ratio. Based on the selectivity and adsorbent selection parameter results, zeolite 5A is a better adsorbent for removing CO2 and N2O from air and separation of CO2 from CH4, whereas MOF-177 is the adsorbent of choice for removing CH 4 from air. However, both MOF adsorbents have larger adsorption capacities for CO2 and CH4 than zeolite 5A at elevated pressures, suggesting MOF-5 and MOF-177 are better adsorbents for CO2 and CH4 storage. The CH4 adsorption capacity of 22 wt.% on MOF-177 at 298K and 100 bar is probably the largest adsorption uptake of CH4 on any dry adsorbents. The average diffusivity of CO2, CH4 and N2O in MOF-5 and MOF-177 is in the order of 10-9 m2/s, as compared to 10-11 m2/s for CO2, CH4 and N2O in zeolite 5A. The effects of gas pressure on diffusivity for different adsorabte-adsorbent systems were also investigated. © 2010 American Chemical Society.

Shao W.,Zhejiang University
Science of the Total Environment | Year: 2010

The rapid economic growth in China has caused ever-increasing pollution and gradual deterioration of surface water quality over the whole territory of China since 1978. Along with it, there have been 130 environmental protection policies publicized and enacted. Unfortunately, even though these contradictory phenomena have coexisted for almost three decades, the cause analysis and the effective evaluation of policy measures are still rare. The Jiaxing region, a lowland located at the Taihu Lake watershed, is a typical representative of this dilemma and was proposed as a case study area for an assessment on the effectiveness of the environmental policy measures mentioned above. The pollutant loads originating from point pollution sources were discharged into rivers at fixed in-stream sites, while pollutant loads from non-point pollution sources in rural areas were assumed to be rushed into rivers by stormwater runoff. The environmental policy measures concerning water quality in the Jiaxing region were specified quantitatively as parameters for estimating the variation of pollutant loads. The base case and other three cases with the effects of policy measures were then simulated by the surface water quality models. The results show that a significant improvement of the surface water quality can be achieved by controlling the non-point pollution in rural areas and the point pollution over the whole area, if the water protection policies are sustainable and executed completely, and if the local government is active in their administrative, supervising and educational responsibilities and the farmers assume voluntary activities on rural pollution control. © 2009 Elsevier B.V. All rights reserved.

Fang W.,Zhejiang University | St. Leger R.J.,University of Maryland University College
PLoS ONE | Year: 2012

The low survival of microbial pest control agents exposed to UV is the major environmental factor limiting their effectiveness. Using gene disruption we demonstrated that the insect pathogenic fungus Metarhizium robertsii uses photolyases to remove UV-induced cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) photoproducts [(6-4)PPs] from its DNA. However, this photorepair is insufficient to fix CPD lesions and prevent the loss of viability caused by seven hours of solar radiation. Expression of a highly efficient archaeal (Halobacterium salinarum) CPD photolyase increased photorepair &30-fold in both M. robertsii and Beauveria bassiana. Consequently, transgenic strains were much more resistant to sunlight and retained virulence against the malaria vector Anopheles gambiae. In the field this will translate into much more efficient pest control over a longer time period. Conversely, our data shows that deleting native photolyase genes will strictly contain M. robertsii to areas protected from sunlight, alleviating safety concerns that transgenic hypervirulent Metarhizium spp will spread from mosquito traps or houses. The precision and malleability of the native and transgenic photolyases allows design of multiple pathogens with different strategies based on the environments in which they will be used. © 2012 Fang, St. Leger.

Wang W.,Zhejiang University
Journal of Geometry and Physics | Year: 2011

The Cauchy-Fueter operator on the quaternionic space Hn induces the tangential Cauchy-Fueter operator on the boundary of a domain. The quaternionic Heisenberg group is a standard model of the boundaries. By using the Penrose transformation associated to a double fibration of homogeneous spaces of Sp(2N,C), we construct an exact sequence on the quaternionic Heisenberg group, the tangential k-Cauchy-Fueter complex, resolving the tangential k-Cauchy-Fueter operator Q0 (k) · Q0 (1) is the tangential Cauchy-Fueter operator. The complex gives the compatible conditions under which the non-homogeneous tangential k-Cauchy-Fueter equations Q0 (k)u=f are solvable. The operators in this complex are left invariant differential operators on the quaternionic Heisenberg group. This is a quaternionic version of ∂b-complex on the Heisenberg group in the theory of several complex variables. © 2010 Elsevier B.V.

Long L.,Zhejiang University
International Journal of Theoretical Physics | Year: 2011

In this paper, we study the fixed points sets of a class of general quantum operations. We show that under some conditions, the fixed points sets of this class of quantum operations are trivial. Finally, we offer a sufficient and necessary condition in a special setting to ensure the fixed points sets are non-trivial. © 2011 Springer Science+Business Media, LLC.

Du Y.Z.,Zhejiang University
International journal of nanomedicine | Year: 2011

Cationic polymers have been accepted as effective nonviral vectors for gene delivery with low immunogenicity unlike viral vectors. However, the lack of organ or cell specificity sometimes hampers their application and the modification of polymeric vectors has also shown successful improvements in achieving cell-specific targeting delivery and in promoting intracellular gene transfer efficiency. A folic acid-conjugated stearic acid-grafted chitosan (FA-CS-SA) micelle, synthesized by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-coupling reaction, was designed for specific receptor-mediated gene delivery. Due to the cationic properties of chitosan, the micelles could compact the plasmid DNA (pDNA) to form micelle/pDNA complexes nanoparticles. The particle size and zeta potential of the FA-CS-SA/pDNA complexes with different N/P ratios were 100-200 nm and -20 to -10 mV, respectively. The DNase I protection assay indicated that the complexes can efficiently protect condensed DNA from enzymatic degradation by DNase I. A cytotoxicity study indicated that the micelles exhibited less toxicity in comparison with Lipofectamine™ 2000. Using SKOV3 and A549 as model tumor cells, the cellular uptake of micelles was investigated. It was found that cellular uptake of FA-CS-SA in SKOV3 cells with higher folate receptor expression was faster than that in A549 cells with a short incubation time. Luciferase assay and green fluorescent protein detection were used to confirm that FA-CS-SA could be an effective gene vector. Transfection efficiency of the FA-CS-SA/pDNA complexes in SKOV3 cells was enhanced up to 2.3-fold compared with that of the CS-SA/pDNA complexes. However, there was no significant difference between the transfection efficiencies of the two complexes in A549 cells. Importantly, the transfection efficiency of FA-CS-SA/pDNA decreased with free FA pretreatment in SKOV3 cells. It was concluded that the increase in transfection efficiency of the FA-CS-SA/pDNA complexes was attributed to folate receptor-mediated endocytosis.

Multidrug resistance remains a major obstacle to successful cancer chemotherapy. Some chemical multidrug resistance inhibitors, such as ciclosporin and verapamil, have been reported to reverse resistance in tumor cells. However, the accompanying side effects have limited their clinical application. In this study, we have developed a novel drug delivery system, ie, a polyethyleneglycol-polycaprolactone (PEG-PCL) copolymer micelle encapsulating doxorubicin, in order to circumvent drug resistance in adriamycin-resistant K562 tumor cells. Doxorubicin-loaded diblock copolymer PEG-PCL micelles were developed, and the physicochemical properties of these micelles, and accumulation and cytotoxicity of doxorubicin in adriamycin-resistant K562 tumor cells were studied. Doxorubicin-loaded micelles were prepared using a solvent evaporation method with a diameter of 36 nm and a zeta potential of +13.8 mV. The entrapment efficiency of doxorubicin was 48.6% ± 2.3%. The micelles showed sustained release, increased uptake, and cellular cytotoxicity, as well as decreased efflux of doxorubicin in adriamycin-resistant K562 tumor cells. This study suggests that PEG-PCL micelles have the potential to reverse multidrug resistance in tumor cells.

Zhang F.,Zhejiang University
The International journal of oral & maxillofacial implants | Year: 2011

The purpose of this study was to exploit potential methods of surface modification for improving the seal between the neck portion of a dental implant and the surrounding soft tissue. Titanium surfaces were modified by machining (SM-Ti group); machining and acid etching (AE-Ti group); or machining, acid etching, and depositing 4.5 collagen/hyaluronic acid (col/HA) polyelectrolyte bilayers (CHC-Ti group). These were analyzed using scanning electron microscopy, scanning force microscopy, x-ray photoelectron spectroscopy, contact angle measurement, and quartz crystal microbalance measurement. The degradation behavior of the col/HA multilayer coating was measured. Next, human gingival fibroblasts (HGFs) were cultured on the different surfaces, and cell morphology and spreading were observed using fluorescence microscopy and a shape factor measurement. Cell proliferation was examined by fluorometric quantification of the amount of cellular DNA. Matrix formation of HGFs was determined via enzyme-linked immunosorbent assay. Gene expression was analyzed via reverse transcriptase polymerase chain reaction. Similar surface topology for these three groups was observable on a microscopic scale, and morphologic differences were apparent on the nanoscale. Both acid etching and col/HA deposition improved the hydrophilicity of the titanium surface, in contrast to machining alone. Each col/HA bilayer was about 5 nm thick. The col/HA coating degraded in about a week. Attachment and spreading of HGFs was better on the CHC-Ti surface than on the SM-Ti or AE-Ti surfaces. Moreover, the proliferation and differentiation of HGFs were greatly stimulated when cultured on CHC-Ti. In contrast to two control surfaces (one machined, one machined and acid-etched), col/HA treatment of Ti improved the attachment, spreading, proliferation, and differentiation of HGFs.

Zhou Z.,Zhejiang University
BMC bioinformatics | Year: 2012

Streptomycetes are filamentous soil-dwelling bacteria. They are best known as the producers of a great variety of natural products such as antibiotics, antifungals, antiparasitics, and anticancer agents and the decomposers of organic substances for carbon recycling. They are also model organisms for the studies of gene regulatory networks, morphological differentiation, and stress response. The availability of sets of genomes from closely related Streptomyces strains makes it possible to assess the mechanisms underlying genome plasticity and systems adaptation. We present the results of a comprehensive analysis of the genomes of five Streptomyces species with distinct phenotypes. These streptomycetes have a pan-genome comprised of 17,362 orthologous families which includes 3,096 components in the core genome, 5,066 components in the dispensable genome, and 9,200 components that are uniquely present in only one species. The core genome makes up about 33%-45% of each genome repertoire. It contains important genes for Streptomyces biology including those involved in gene regulation, secretion, secondary metabolism and morphological differentiation. Abundant duplicate genes have been identified, with 4%-11% of the whole genomes composed of lineage-specific expansions (LSEs), suggesting that frequent gene duplication or lateral gene transfer events play a role in shaping the genome diversification within this genus. Two patterns of expansion, single gene expansion and chromosome block expansion are observed, representing different scales of duplication. Our results provide a catalog of genome components and their potential functional roles in gene regulatory networks and metabolic networks. The core genome components reveal the minimum requirement for streptomycetes to sustain a successful lifecycle in the soil environment, reflecting the effects of both genome evolution and environmental stress acting upon the expressed phenotypes. A better understanding of the LSE gene families will, on the other hand, bring a wealth of new insights into the mechanisms underlying strain-specific phenotypes, such as the production of novel antibiotics, pathogenesis, and adaptive response to environmental challenges.

Wei L.,Zhejiang University
Journal of Computer-Mediated Communication | Year: 2012

This study explores the multimodality of Internet use as a critical indicator of digital inequalities. Rather than relying on traditional measures of user/nonuser and information/entertainment uses, this study focuses on a broad scope of online activities and investigates them collectively. Results show that the more modes of Internet activities people are engaged in, the more advanced uses they will add to their online behaviors. Female, older, poorer, and less educated only use the Internet for very limited basic applications, which are associated with fewer political communication and participation. While previous research concludes that the type of Internet activities matters, this study suggests that it is the number of types that matters in examining potential inequalities and their social consequences. © 2012 International Communication Association.

Wang Q.,Zhejiang University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2013

Due to energy crisis and environmental pollution in the world range, it is urgent to develop new solutions for excavators which are widely applied with low efficiency. As a well-known energy-saving solution, oil-electric hybrid driven technology which combines a diesel engine and an electric motor together has received significant breakthrough in vehicles, for engine efficiency can be improved and energy regeneration can be realized. There are many differences between excavators and vehicles such as load condition, regeneration approach, energy storage, operability and reliability. Therefore, it is necessary to investigate the hybrid driven technology of excavators specially. The key technologies of oil-electric hybrid excavators in China, abroad and especially in SKLoFP of Zhejiang University are reviewed on power hybridization mode and parameter optimization, power system control, electric swing and braking kinetic energy regeneration, boom potential energy regeneration and generator. The research results are validated in a prototype of 20 t hybrid excavator and can also be extended to other construction machinery. © 2013 Journal of Mechanical Engineering.

We explored a possible correlation of genetic instability and CpG methylation in the 5'-flanking region of the PAI-1 gene with clinicopathologic features of gastric cancer in Chinese patients and looked for molecular markers for diagnosing gastric tumor development. Microsatellite instability and loss of heterozygosity of the PAI-1 gene locus D7S515, D7S471 and pai-1 in 50 specimens of gastric cancer and relevant pericancerous tissues were detected by PCR-single strand conformation polymorphism (PCR-SSCP) with sliver staining. Methylation-specific PCR was used to detect CpG methylation in the 5'-flanking region of the PAI-1 gene. Microsatellite instability was significantly more common in the negative than in the positive serosa infiltration group of gastric cancer (42.86 vs 2.33%). The frequency of microsatellite instability was significantly lower in the cases with lymph node metastasis than in those without metastasis (18.18 vs 2.56%); however, it was significantly higher in the low differentiation group than that in the middle or high differentiation groups (21.05 vs 0.00%). CpG methylation in the 5'-flanking region of the PAI-1 gene did not differ significantly. Microsatellite instability and loss of heterozygosity of the PAI-1 gene apparently regulates the development of gastric cancer through different pathways. Microsatellite instability could be used as a molecular marker for the development of gastric cancer. CpG methylation in the 5'-flanking region of the PAI-1 gene appears not to be involved in the development of gastric cancer.

Cheng S.,Zhejiang University | Cheng S.,Pennsylvania State University | Logan B.E.,Pennsylvania State University
Bioresource Technology | Year: 2011

Practical applications of microbial electrolysis cells (MECs) require high hydrogen production rates and a compact reactor. These goals can be achieved by reducing electrode spacing but high surface area anodes are needed. The brush anode MEC with electrode spacing of 2cm had a higher hydrogen production rate and energy efficiency than an MEC with a flat cathode and a 1-cm electrode spacing. The maximum hydrogen production rate with a 2cm electrode spacing was 17.8m3/m3d at an applied voltage of Eap=1V. Reducing electrode spacing increased hydrogen production rates at the lower applied voltages, but not at the higher (>0.6V) applied voltages. These results demonstrate that reducing electrode spacing can increase hydrogen production rate, but that the closest electrode spacing do not necessarily produce the highest possible hydrogen production rates. © 2010 Elsevier Ltd.

RATIONALE:: The effectiveness of transplanted bone marrow mesenchymal stem cells (MSCs) for cardiac repair has been limited; thus, strategies for optimizing stem-cell based myocardial therapy are needed. OBJECTIVE:: The present study was designed to test our central hypothesis that hypoxia preconditioned MSCs (HP-MSCs) are more effective than MSCs cultured under ambient oxygen levels (N-MSCs) for the treatment of myocardial injury in a large-scale (N=49), long-term (9 months), non-human primate (Cynomolgous monkeys) investigation. METHODS AND RESULTS:: MSCs were engineered to express green fluorescent protein, cultured under ambient oxygen (N-MSCs) or 0.5% oxygen (HP-MSCs) for 24 hours, and then tested in the infarcted hearts of Cynomolgus monkeys(1×10 cells per heart). HP increased the expression of several pro-survival/pro-angiogenic factors in cultured MSCs, and measurements of infarct size and left-ventricular function at Day 90 after myocardial infarction (MI) were significantly more improved in monkeys treated with HP-MSCs than in monkeys treated with the control vehicle; functional improvements in N-MSCs-treated monkeys were not significant. HP-MSCs transplantation was also associated with increases in cardiomyocyte proliferation, vascular density, myocardial glucose uptake, and engraftment of the transplanted cells, and with declines in endogenous cell apoptosis, but did not increase the occurrence of arrhythmogenic complications. CONCLUSIONS:: HP improved the effectiveness of MSCs transplantation for the treatment of MI in nonhuman primates without increasing the occurrence of arrhythmogenic complications, which suggests that future clinical trials of HP-MSCs transplantation are warranted.Circulation Research is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial-NoDervis License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is noncommercial, and no modifications or adaptations are made. © 2016 American Heart Association, Inc.

Dong W.,Zhejiang University
Protein & cell | Year: 2012

Heparinase III (HepIII) is a 73-kDa polysaccharide lyase (PL) that degrades the heparan sulfate (HS) polysaccharides at sulfate-rare regions, which are important co-factors for a vast array of functional distinct proteins including the well-characterized antithrombin and the FGF/FGFR signal transduction system. It functions in cleaving metazoan heparan sulfate (HS) and providing carbon, nitrogen and sulfate sources for host microorganisms. It has long been used to deduce the structure of HS and heparin motifs; however, the structure of its own is unknown. Here we report the crystal structure of the HepIII from Bacteroides thetaiotaomicron at a resolution of 1.6 Å. The overall architecture of HepIII belongs to the (α/α)5 toroid subclass with an N-terminal toroid-like domain and a C-terminal β-sandwich domain. Analysis of this high-resolution structure allows us to identify a potential HS substrate binding site in a tunnel between the two domains. A tetrasaccharide substrate bound model suggests an elimination mechanism in the HS degradation. Asn260 and His464 neutralize the carboxylic group, whereas Tyr314 serves both as a general base in C-5 proton abstraction, and a general acid in a proton donation to reconstitute the terminal hydroxyl group, respectively. The structure of HepIII and the proposed reaction model provide a molecular basis for its potential practical utilization and the mechanism of its eliminative degradation for HS polysaccarides.

Meng Q.,Zhejiang University
Expert Opinion on Drug Metabolism and Toxicology | Year: 2010

Importance of the field: Hepatotoxicity is the most frequent reason for the withdrawal of an approved drug from the market. Monolayer culture of hepatocyte in two-dimension, which is relatively inexpensive, convenient and easy to use, serves a traditional hepatocyte-based high-content screening for identifying hepatotoxic side effects of tested drugs. However, two-dimensional methods have their limitations in lack of insensitivity on reflection of drug hepatotoxicity. Three-dimensional (3D) cultures of hepatocytes in sandwich, spheroid and gel entrapment provide a microenvironment for high expression of liver-specific functions and are being proposed for prediction of drug hepatotoxicity. Areas covered in this review: This review addressed the reliability of 3D culture models on screening hepatotoxic drugs with particular emphasis on gel entrapment culture model due to its more systematic data on drug testing. What the reader will gain: The reader will gain a comprehensive understanding of the improved prediction efficacy of 3D culture models. Take home message: Hepatocytes in 3D cultures, although in need of further standardization required by the throughput operation, show great potential in attempts to ensure the efficacy on prediction of drug hepatotoxicity. © Informa UK Ltd.

Shan H.,Zhejiang University | Cheng H.T.,Huawei | Zhuang W.,University of Waterloo
IEEE Transactions on Wireless Communications | Year: 2011

In this paper, we study medium access control (MAC) protocol design for distributed cooperative wireless networks. We focus on beneficial node cooperation by addressing two fundamental issues of cooperative communications, namely when to cooperate and whom to cooperate with, from a cross-layer protocol design perspective. In the protocol design, taking account of protocol overhead we explore a concept of cooperation region, whereby beneficial cooperative transmissions can be identified. We show that a rate allocation in the cooperation region provides higher link utilization than in a non-cooperation region. To increase network throughput, we propose an optimal grouping strategy for efficient helper node selection, and devise a greedy algorithm for MAC protocol refinement. Analysis of a successful transmission probability with cooperative or direct transmission is presented. Simulation results show that the proposed approach can effectively exploit beneficial cooperation, thereby improving system performance. Further, analytical and simulation results shed some light on the tradeoff between multi-user diversity gain at the physical layer and the helper contention overhead at the MAC layer. © 2006 IEEE.

Mohanty A.,Purdue University | Yao B.,Purdue University | Yao B.,Zhejiang University
IEEE Transactions on Control Systems Technology | Year: 2011

In a general direct adaptive robust control (DARC) framework, the emphasis is always on the guaranteed transient performance and accurate trajectory tracking in presence of uncertain nonlinearities and parametric uncertainties. Such a direct algorithm suffers from lack of modularity, controller-estimator inseparability, and poor convergence of parameter estimates. In the DARC design the parameters are estimated by gradient law with the sole purpose of reducing tracking error, which is typical of a Lyapunov-type design. However, when the controller-estimator module is expected to assist in secondary purposes such as health monitoring and fault detection, the requirement of having accurate online parameter estimates is as important as the need for the smaller tracking error. In this paper, we consider the trajectory tracking of a robotic manipulator driven by electro-hydraulic actuators. The controller is constructed based on the indirect adaptive robust control (IARC) framework with necessary design modifications required to accommodate uncertain and nonsmooth nonlinearities of the hydraulic system. The online parameter estimates are obtained through a parameter adaptation algorithm that is based on physical plant dynamics rather than the tracking error dynamics. While the new controller preserves the nice properties of the DARC design such as prescribed output tracking transient performance and final tracking accuracy, more accurate parameter estimates are obtained for prognosis and diagnosis purpose. Comparative experimental results are presented to show the effectiveness of the proposed algorithm. © 2006 IEEE.

Song J.,Zhejiang University
Current Opinion in Solid State and Materials Science | Year: 2015

Abstract Recent advances in mechanics and materials provide routes to develop stretchable electronics that offer performance of conventional wafer-based devices but with the ability to be deformed to arbitrary shape. Many new applications become possible ranging from electronic eye cameras to wearable electronics, to bio-integrated therapeutic devices. This paper reviews mechanics of stretchable electronics in terms of two main forms of stretchable designs. One is wavy design, which can provide one-dimensional stretchability. The other is island-bridge design, which can be stretched in all directions. Mechanics models and their comparisons to experiments and finite element simulations are reviewed for these two designs. The results provide design guidelines for the development of stretchable electronics. © 2015 Elsevier Ltd.

Shi F.,Wenzhou Medical College | Sun S.,Zhejiang University | Xu J.,Nanjing Southeast University
Information Sciences | Year: 2012

KANSEI Engineering (KE) is a method for translating feelings and impressions into product parameters and the objective of KANSEI Engineering is to study the relationship between product forms and KANSEI images. It is most important to extract critical form features of the product relative to specific KANSEI adjectives through a WEB-based KANSEI information system. In this paper, critical form features and KANSEI adjectives were defined as condition attributes and decision attributes respectively, which were formalized as two objects in Decision Table (DT). Then, the Semantic Differential (SD), which measures the connotative meaning of concepts, was applied to evaluate form features of the product through a KANSEI questionnaire system. The evaluation record from an individual's transaction data was reserved if its frequency was higher than the given threshold. Some form features were deleted by using an attribute reduction algorithm based on Rough Sets Theory (RST). Furthermore, the size of the DT was reduced by using a rule-joining operation. A strong association rule set which describes the relationship between the critical form features and the corresponding KANSEI adjectives was subsequently generated. A case study of a mobile phone design was presented to demonstrate the effectiveness of the proposed method by comparing it with other non-linear data mining methods in KANSEI Engineering. © 2012 Elsevier Inc. All rights reserved.

Zhang L.,Zhejiang University | Xu Q.,Kings College London
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2014

A series of studies has been presented in the search for proof of circulating and resident vascular progenitor cells, which can differentiate into endothelial and smooth muscle cells and pericytes in animal and human studies. In terms of pluripotent stem cells, including embryonic stem cells, iPS, and partialiPS cells, they display a great potential for vascular lineage differentiation. Development of stem cell therapy for treatment of vascular and ischemic diseases remains a major challenging research field. At the present, there is a clear expansion of research into mechanisms of stem cell differentiation into vascular lineages that are tested in animal models. Although there are several clinical trials ongoing that primarily focus on determining the benefits of stem cell transplantation in ischemic heart or peripheral ischemic tissues, intensive investigation for translational aspects of stem cell therapy would be needed. It is a hope that stem cell therapy for vascular diseases could be developed for clinic application in the future. © 2014 American Heart Association, Inc.

Cheng S.,Zhejiang University | Cheng S.,Pennsylvania State University | Logan B.E.,Pennsylvania State University
Bioresource Technology | Year: 2011

Scaling up microbial fuel cells (MFCs) requires a better understanding the importance of the different factors such as electrode surface area and reactor geometry relative to solution conditions such as conductivity and substrate concentration. It is shown here that the substrate concentration has significant effect on anode but not cathode performance, while the solution conductivity has a significant effect on the cathode but not the anode. The cathode surface area is always important for increasing power. Doubling the cathode size can increase power by 62% with domestic wastewater, but doubling the anode size increases power by 12%. Volumetric power density was shown to be a linear function of cathode specific surface area (ratio of cathode surface area to reactor volume), but the impact of cathode size on power generation depended on the substrate strength (COD) and conductivity. These results demonstrate the cathode specific surface area is the most critical factor for scaling-up MFCs to obtain high power densities. © 2010 Elsevier Ltd.

He X.,Zhejiang University
IEEE Transactions on Image Processing | Year: 2010

In increasingly many cases of interest in computer vision and pattern recognition, one is often confronted with the situation where data size is very large. Usually, the labels are expensive and the challenge is, thus, to determine which unlabeled samples would be the most informative (i.e., improve the classifier the most) if they were labeled and used as training samples. Particularly, we consider the problem of active learning of a regression model in the context of experimental design. Classical optimal experimental design approaches are based on least square errors over the measured samples only. They fail to take into account the unmeasured samples. In this paper, we propose a novel active learning algorithm which operates over graphs. Our algorithm is based on a graph Laplacian regularized regression model which simultaneously minimizes the least square error on the measured samples and preserves the local geometrical structure of the data space. By constructing a nearest neighbor graph, the geometrical structure of the data space can be described by the graph Laplacian. We discuss how results from the field of optimal experimental design may be used to guide our selection of a subset of data points, which gives us the most amount of information. Experiments demonstrate its superior performance in comparison with conventional algorithms. © 2009 IEEE.

Ouyang Y.,Zhejiang University
Information Sciences | Year: 2015

The determination of weights vector is one of the key issues in the theory of ordered weighted averaging (OWA) operators. For this reason, many weight generating models have been proposed in the literature. The main purpose of this note is to point out that the improved minimax disparity model, which is suggested by Emrouznejad and Amin (2010), has infinite solutions. As a consequence, this model is not reliable. © 2015 Elsevier Inc. All rights reserved.

Ye F.Y.,Zhejiang University | Ye F.Y.,Information Assurance
Journal of the American Society for Information Science and Technology | Year: 2011

Among existing theoretical models for the h-index, Hirsch's original approach, the Egghe-Rousseau model, and the Glänzel-Schubert model are the three main representatives. Assuming a power-law relation or Heaps' law between publications and citations a unified theoretical explanation for these three models is provided. It is shown that on the level of universities, the Glänzel-Schubert model fits best. © 2010 ASIS&T.

Zhang H.,Zhejiang University | Jin M.,Xian University of Science and Technology | Xiong Y.,Anhui University of Science and Technology | Lim B.,Sungkyunkwan University | Xia Y.,Georgia Institute of Technology
Accounts of Chemical Research | Year: 2013

Palladium is a marvelous catalyst for a rich variety of reactions in industrial processes and commercial devices. Most Pd-catalyzed reactions exhibit structure sensitivity, meaning that the activity or selectivity depends on the arrangement of atoms on the surface. Previously, such reactions could only be studied in ultrahigh vacuum using Pd single crystals cut with a specific crystallographic plane. However, these model catalysts are far different from real catalytic systems owing to the absence of atoms at corners and edges and the extremely small specific surface areas for the model systems. Indeed, enhancing the performance of a Pd-based catalyst, in part to reduce the amount needed of this precious and rare metal for a given reaction, requires the use of Pd with the highest possible specific surface area. Recent advances in nanocrystal synthesis are offering a great opportunity to investigate and quantify the structural sensitivity of catalysts based on Pd and other metals. For a structure-sensitive reaction, the catalytic properties of Pd nanocrystals are strongly dependent on both the size and shape. The shape plays a more significant role in controlling activity and selectivity, because the shape controls not only the facets but also the proportions of surface atoms at corners, edges, and planes, which affect the outcomes of possible reactions. We expect catalysts based on Pd nanocrystals with optimized shapes to meet the increasing demands of industrial applications at reduced loadings and costs.In this Account, we discuss recent advances in the synthesis of Pd nanocrystals with controlled shapes and their resulting performance as catalysts for a large number of reactions. First, we review various synthetic strategies based on oxidative etching, surface capping, and kinetic control that have been used to direct the shapes of nanocrystals. When crystal growth is under thermodynamic control, the capping agent plays a pivotal role in determining the shape of a product by altering the order of surface energies for different facets through selective adsorption; the resulting product has the lowest possible total surface energy. In contrast, the product of a kinetically controlled synthesis often deviates from the thermodynamically favored structure, with notable examples including nanocrystals enclosed by high-index facets or concave surfaces.We then discuss the key parameters that control the nucleation and growth of Pd nanocrystals to decipher potential growth mechanisms and build a connection between the experimental conditions and the pathways to different shapes. Finally, we present a number of examples to highlight the use of these Pd nanocrystals as catalysts or electrocatalysts for various applications with structure-sensitive properties. We believe that a deep understanding of the shape-dependent catalytic properties, together with an ability to experimentally maneuver the shape of metal nanocrystals, will eventually lead to rational design of advanced catalysts with substantially enhanced performance. © 2012 American Chemical Society.

Liu T.,Zhejiang University
Cellular and molecular life sciences : CMLS | Year: 2014

Exogenous and endogenous genotoxic agents, such as ionizing radiation and numerous chemical agents, cause DNA double-strand breaks (DSBs), which are highly toxic and lead to genomic instability or tumorigenesis if not repaired accurately and efficiently. Cells have over evolutionary time developed certain repair mechanisms in response to DSBs to maintain genomic integrity. Major DSB repair mechanisms include non-homologous end joining and homologous recombination (HR). Using sister homologues as templates, HR is a high-fidelity repair pathway that can rejoin DSBs without introducing mutations. However, HR execution without appropriate guarding may lead to more severe gross genome rearrangements. Here we review current knowledge regarding the factors and mechanisms required for accomplishment of accurate HR.

Yu Y.,Zhejiang University
Oncogene | Year: 2015

Smad and STAT proteins are critical signal transducers and transcription factors in controlling cell growth and tumorigenesis. Here we report that the STAT3 signaling pathway attenuates transforming growth factor-β (TGF-β)-induced responses through a direct Smad3–STAT3 interplay. Activated STAT3 blunts TGF-β-mediated signaling. Depletion of STAT3 promotes TGF-β-mediated transcriptional and physiological responses, including cell cycle arrest, apoptosis and epithelial-to-mesenchymal transition. STAT3 directly interacts with Smad3 in vivo and in vitro, resulting in attenuation of the Smad3–Smad4 complex formation and suppression of DNA-binding ability of Smad3. The N-terminal region of DNA-binding domain of STAT3 is responsible for the STAT3–Smad3 interaction and also indispensable for STAT3-mediated inhibition of TGF-β signaling. Thus, our finding illustrates a direct crosstalk between the STAT3 and Smad3 signaling pathways that may contribute to tumor development and inflammation.Oncogene advance online publication, 30 November 2015; doi:10.1038/onc.2015.446. © 2015 Macmillan Publishers Limited

Zhang J.,Zhejiang University
International journal of environmental research and public health | Year: 2011

Sustainable ecological and environmental development is the basis of regional development. The sensitivity classification of the ecological environment is the premise of its spatial distribution for land use planning. In this paper, a fuzzy matter-element model and factor-overlay method were employed to analyze the ecological sensitivity in Yicheng City. Four ecological indicators, including soil condition,, water condition,, atmospheric conditions and biodiversity were used to classify the ecological sensitivity. The results were categorized into five ranks: insensitive, slightly sensitive, moderately sensitive, highly sensitive and extremely sensitive zones. The spatial distribution map of environmental sensitivity for land use planning was obtained using GIS (Geographical Information System) techniques. The results illustrated that the extremely sensitive and highly sensitive areas accounted for 14.40% and 30.12% of the total area, respectively, while the moderately sensitive and slightly sensitive areas are 25.99% and 29.49%, respectively. The results provide the theoretical foundation for land use planning by categorizing all kinds of land types in Yicheng City.

Gong Y.,Shanghai JiaoTong University | Zhang Y.,Shanghai JiaoTong University | Yuan W.Z.,Shanghai JiaoTong University | Sun J.Z.,Zhejiang University
Journal of Physical Chemistry C | Year: 2014

Multifunctional and mechanochromic optoelectronic materials are of significant importance in both academic and technical aspects. In this contribution, a novel D-A conjugate (AN2TPAN), consisting of arylamine and two triphenylacrylonitrile (TPAN) units, with sterically crowded and remarkably twisted conformations, has been carefully designed and synthesized. It shows typical intramolecular charge transfer, aggregation-induced emission, and aggregation-enhanced two-photon absorption characteristics. Moreover, it exhibits more than three emission colors in the solid state upon mechanical grinding. Such multicolor mechanochromism for solid emitters under mild conditions is rarely reported. A multilayer nondoped OLED device of AN2TPAN is fabricated and performs excellently, whose maximal current and external quantum efficiencies are as high as 10.7 cd/A and 3.3%, respectively. The multifunctionality and multicolor mechanochromism of AN2TPAN make it promising in optoelectronic applications. © 2014 American Chemical Society.

Chen J.-R.,Zhejiang University
Cell Death and Differentiation | Year: 2016

Deafness or hearing loss is a major issue in human health. Inner ear hair cells are the main sensory receptors responsible for hearing. Defects in hair cells are one of the major causes of deafness. A combination of induced pluripotent stem cell (iPSC) technology with genome-editing technology may provide an attractive cell-based strategy to regenerate hair cells and treat hereditary deafness in humans. Here, we report the generation of iPSCs from members of a Chinese family carrying MYO15A c.4642G>A and c.8374G>A mutations and the induction of hair cell-like cells from those iPSCs. The compound heterozygous MYO15A mutations resulted in abnormal morphology and dysfunction of the derived hair cell-like cells. We used a CRISPR/Cas9 approach to genetically correct the MYO15A mutation in the iPSCs and rescued the morphology and function of the derived hair cell-like cells. Our data demonstrate the feasibility of generating inner ear hair cells from human iPSCs and the functional rescue of gene mutation-based deafness by using genetic correction.Cell Death and Differentiation advance online publication, 26 February 2016; doi:10.1038/cdd.2016.16. © 2016 Macmillan Publishers Limited

The plant SNF1-related kinase (SnRK1) is the α-subunit of the SnRK1 heterotrimeric compleses. Although SnRK1 is widely known as a key regulator of plant response to various physiological processes including nutrient- and energy-sensing, regulation of global metabolism, and control of cell cycle, development, as well as abiotics stress, less is known about the function of SnRK1 during pathogen infection. Our previous work has demonstrated that a tomato SNF1-related kinase (SlSnRK1) can interact with and phosphorylate βC1, a pathogenesis protein encoded by tomato yellow leaf curl China betasatellite. Our results also showed that the plant SnRK1 can affect genimivirus infection in plant and reduce viral DNA accumulation. Phosphorylation of βC1 protein negatively impacts its function as a pathogenicity determinant. Here we provide more information on interaction between βC1 and SlSnRK1 and propose a mechanistic model for the SlSnRK1-mediated defense responses against geminiviruses and the potential role of SnRK1 in plant resistance to geminivirus.

Ye F.Y.,Zhejiang University
Journal of the American Society for Information Science and Technology | Year: 2011

A simple distribution function f(x, t)=p(x+q)-βe αt obeys wave and heat equations, that constructs a theoretical approach to the unification of informetric models, with which we can unify all informetric laws. While its space-type distributions deduce naturally Lotka-type laws in size approaches and Zipf-type laws in rank approaches, its time-type distributions introduce the mechanism of Price-type and Brookes-type laws. © 2011 ASIS&T.

Guo B.,Zhejiang University
International Journal of Information Management | Year: 2011

As a first attempt to empirically investigate the scope of external information-seeking under uncertainty, this paper examines the direct and interactive effects of task uncertainty on the scope of external information-seeking. Search depth and breadth are the two components of the scope of external information-seeking in defining an individual's external information search strategy. The empirical results show that at the source portfolio level, task uncertainty exhibits positive effects on both the depth and breadth of external information-seeking. It is also found that there is a positive relationship between task uncertainty and depth-first propensity, which is defined as a seeker's propensity to acquire information through increasing search depth instead of through widening search breadth at the source portfolio level. Furthermore, the results show that the positive relationship between task uncertainty and depth-first propensity in external information-seeking is stronger when perceived source accessibility is low than when it is high. This study makes a contribution to the information-seeking literature by helping us understand how task uncertainty and source characteristics shape an individual's external information-seeking at the level of source portfolio and providing evidence of the task-source fit perspective in explaining information-seeking behaviour under uncertainty at the source portfolio level. © 2010 Elsevier Ltd. All rights reserved.

Jiang D.,National University of Singapore | Tung A.K.H.,National University of Singapore | Chen G.,Zhejiang University
IEEE Transactions on Knowledge and Data Engineering | Year: 2011

Data analysis is an important functionality in cloud computing which allows a huge amount of data to be processed over very large clusters. MapReduce is recognized as a popular way to handle data in the cloud environment due to its excellent scalability and good fault tolerance. However, compared to parallel databases, the performance of MapReduce is slower when it is adopted to perform complex data analysis tasks that require the joining of multiple data sets in order to compute certain aggregates. A common concern is whether MapReduce can be improved to produce a system with both scalability and efficiency. In this paper, we introduce Map-Join-Reduce, a system that extends and improves MapReduce runtime framework to efficiently process complex data analysis tasks on large clusters. We first propose a filtering-join-aggregation programming model, a natural extension of MapReduce's filtering-aggregation programming model. Then, we present a new data processing strategy which performs filtering-join-aggregation tasks in two successive MapReduce jobs. The first job applies filtering logic to all the data sets in parallel, joins the qualified tuples, and pushes the join results to the reducers for partial aggregation. The second job combines all partial aggregation results and produces the final answer. The advantage of our approach is that we join multiple data sets in one go and thus avoid frequent checkpointing and shuffling of intermediate results, a major performance bottleneck in most of the current MapReduce-based systems. We benchmark our system against Hive, a state-of-the-art MapReduce-based data warehouse on a 100-node cluster on Amazon EC2 using TPC-H benchmark. The results show that our approach significantly boosts the performance of complex analysis queries. © 2006 IEEE.

Zhang X.,Dalian University of Technology | Xu S.,Zhejiang University
Engineering Fracture Mechanics | Year: 2011

The current paper presents a comprehensive comparison of double-K fracture toughness parameters of concrete evaluated using experimental method and four existing analytical methods. Fracture tests were carried out on compact tension wedge splitting specimens with various depths varying from 200. mm up to 1000. mm. In the analytical calculation, depending on the relationship between critical crack tip opening displacement and the abscissa value of turning point on bilinear softening curve, two different distributions of cohesive stress are considered along crack extension. Results show that four available analytical calculations yield almost the same values of double-K fracture toughness parameters and agree well with those obtained from the experiment, which confirms the consistency of five approaches. Size effect was discussed, including unstable fracture toughness, initiation fracture toughness, critical effective crack length, the length of critical fracture process zone and critical crack tip opening displacement. © 2011 Elsevier Ltd.

Zhou X.,Zhejiang University
Methods in molecular biology (Clifton, N.J.) | Year: 2012

Virus-induced gene silencing (VIGS) has emerged as a powerful method for studying gene function. VIGS is induced by infecting a plant with a plant virus that has had its genome modified to include a sequence from the host gene to be silenced. DNAβ and DNA1 are satellite and single-stranded DNA molecules associated with begomoviruses (family Geminiviridae). We converted DNAβ and DNA1 into gene-silencing vectors. The VIGS vectors can induce silencing efficiently in many solanaceous plants. Here, we describe procedures for the use of these two gene-silencing vectors for VIGS in different hosts.

Zhu S.,Zhejiang University
Journal of High Energy Physics | Year: 2013

In this paper, we study the properties of the colored HOMFLY polynomials via HOMFLY skein theory. We prove some limit behaviors and symmetries of the colored HOMFLY polynomials predicted in some physicists' recent works. © SISSA 2013.

Chen X.,KTH Royal Institute of Technology | Chen Y.,KTH Royal Institute of Technology | Yan M.,KTH Royal Institute of Technology | Qiu M.,KTH Royal Institute of Technology | Qiu M.,Zhejiang University
ACS Nano | Year: 2012

Photothermal effects in plasmonic nanostructures have great potentials in applications for photothermal cancer therapy, optical storage, thermo-photovoltaics, etc. However, the transient temperature behavior of a nanoscale material system during an ultrafast photothermal process has rarely been accurately investigated. Here a heat transfer model is constructed to investigate the temporal and spatial variation of temperature in plasmonic gold nanostructures. First, as a benchmark scenario, we study the light-induced heating of a gold nanosphere in water and calculate the relaxation time of the nanosphere excited by a modulated light. Second, we investigate heating and reshaping of gold nanoparticles in a more complex metamaterial absorber structure induced by a nanosecond pulsed light. The model shows that the temperature of the gold nanoparticles can be raised from room temperature to >795 K in just a few nanoseconds with a low light luminance, owing to enhanced light absorption through strong plasmonic resonance. Such quantitative predication of temperature change, which is otherwise formidable to measure experimentally, can serve as an excellent guideline for designing devices for ultrafast photothermal applications. © 2012 American Chemical Society.

Li C.,Zhejiang University
IEEE Transactions on Autonomous Mental Development | Year: 2011

Recent experimental results have accumulated evidence that the neurons can change their response characteristics to adapt to the variations of the synaptic inputs, which is the so-called neuronal intrinsic plasticity mechanism. In this paper, we present a new model on neuronal intrinsic plasticity. We first show that the probability distribution of the neuronal firing rates is more suitable to be represented as a Weibull distribution than an exponential distribution. Then, we derive the intrinsic plasticity model based on information theory. This study provides a more realistic model for further research on the effects of intrinsic plasticity on various brain functions and dynamics. © 2009 IEEE.

Wang J.,Zhejiang University
Applied Physics Letters | Year: 2010

The polarization switching in a single-crystal ferroelectric tetragonal nanodot subjected to curled electric fields is investigated by a phase field model. The simulation results show that the switching of polarization vortex in the tetragonal nanodot does not begin from the location with the highest energy density, which is different from those of ferroelectric nanotubes and ferroelectric cylindrical nanodots. It is found that the vortex switching begins from the dot corners with the lowest elastic energy density, which implies that the elastic constraint as well as the geometry play an important role on the switching of polarization vortex in ferroelectric nanostructures. © 2010 American Institute of Physics.

Zhou Z.,Zhejiang University
Plant signaling & behavior | Year: 2012

The Arabidopsis thaliana trichome development is a model system for understanding various aspects of plant cell development and differentiation. The C2H2 zinc finger proteins GIS, GIS2, and ZFP8 play important roles in controlling trichome initiation. In our recent study, we reported that a new C2H2 zinc finger protein, ZINC FINGER PROTEIN 5 (ZFP5), controls trichome cell development through GA signaling. ZFP5 acts upstream of GIS gene family and key trichome initiation regulators, and ZFP8 is the direct target gene of ZFP5. Here we show that ZFP5 encodes a protein functionally equivalent to GIS and GIS2 in controlling trichome initiation. Furthermore, similar to GIS2, ZFP5 is not involved in trichome branching.

Shade A.,Michigan State University | Gilbert J.A.,Argonne National Laboratory | Gilbert J.A.,University of Chicago | Gilbert J.A.,National Oceanic and Atmospheric Administration | Gilbert J.A.,Zhejiang University
Trends in Microbiology | Year: 2015

Recently, conditionally rare taxa (CRTs) - those taxa that are typically in very low abundance but occasionally achieve prevalence - were shown to contribute to patterns of microbial diversity because their collective dynamics explained a large proportion of temporal variability in microbial community structure. Here the benefits and challenges of characterizing the presence and interpreting the role of CRTs are further explored, along with questions about CRT ecology. We also introduce a conceptual model for thinking about microbial taxa as dynamic components along the dimensions of occurrence and abundance. Accounting for CRTs in interpretations of microbial ecological dynamics is essential if we are to understand community stability and ecoevolutionary interactions. © 2015 Elsevier Ltd.

The present study evaluated the potential neuroprotective effect and underlying mechanism of the total flavones extracted from Chrysanthemum morifolium (TFCM) against ischemia/reperfusion (I/R) injury. An animal model of cerebral ischemia was established by occluding the right middle cerebral artery for 90 minutes followed by reperfusion for 22 hours. The neurobehavioral scores, infarct area, and hemispheric edema were evaluated. The superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and reactive oxygen species (ROS) level in brain were also measured. The results showed that pretreatment with TFCM significantly decreased the neurological deficit scores, percentage of infarction, and brain edema and attenuated the decrease in SOD activity, the elevation of MDA content, and the generation of ROS. In isolated brain mitochondria, Ca(2+)-induced swelling was attenuated by pretreatment with TFCM, and this effect was antagonized by atractyloside. These results showed that pretreatment with TFCM provides significant protection against cerebral I/R injury in rats by, at least in part, its antioxidant action and consequent inhibition of mitochondrial swelling.

Ye X.,Zhejiang University
Automatica | Year: 2011

In this paper, we consider the adaptive stabilization problem for feedforward nonlinear systems with time delays. An adaptive stabilizer is proposed. Our stabilizer takes a nested saturation feedback, and a set of switching logics is designed to tune online the saturation levels in a piecewise constant or switching manner. It has been shown that under our proposed control, all closed-loop states are bounded and asymptotic regulation is achieved. © 2011 Elsevier Ltd. All rights reserved.

Chen A.,Zhejiang University
Journal of Maternal-Fetal and Neonatal Medicine | Year: 2010

Objective.To determine circadian rhythms of circadian genes in the peripheral blood mononuclear cells in preterm neonates. Study design.Ten premature neonates, gestational age from 30 to 31 weeks were recruited. Infants with birth asphyxia, RDS, apnea, malformation, infection or haemolytic diseases were excluded. At 7AM and 7PM on the 1st day, 7th day and 14th day of hospitalisation, peripheral venous blood was obtained from the premature babies and real-time RTPCR was used to determine the expression of Bmal1 and Cry1. Results.The expression of bmal1 did not have statistical difference between 7AM and 7PM on the 1st day, 7th day and 14th day. Neither did the cry1. Conclusion.There was no circadian rhythm of bmal1 and cry1 in PBMC of preterm neonates in our NICU. © 2010 Informa UK, Ltd.

Wang X.-M.,Zhejiang University
World Journal of Pediatrics | Year: 2013

Metabolic syndrome (MS) has reached epidemic proportions worldwide among children. Early life "programming" is now thought to be important in the etiology of obesity, type 2 diabetes, cardiovascular disease and MS. Nutritional imbalance and exposures to endocrine disruptor chemicals during development can increase risk for MS later in life. Epigenetic marks may be reprogrammed in response to both stochastic and environmental stimuli, such as changes in diet and the in utero environment, therefore, determination of targets for early life effects on epigenetic gene regulation provides insight into the molecular mechanisms involved in the epigenetic transgenerational inheritance of a variety of adult onset disease phenotypes. The perinatal period is a crucial time of growth, development and physiological changes in mother and child, which provides a window of opportunity for early intervention that may induce beneficial physiological alternations. © 2013 Children's Hospital, Zhejiang University School of Medicine and Springer-Verlag Berlin Heidelberg.

Dai J.,Zhejiang University
Information Sciences | Year: 2013

Rough set theory has been applied successfully in many fields. However, classical rough set model can only deal with complete and symbolic data sets. Some researchers have proposed extended rough set models to handle incomplete data while others proposed extensions of classical rough set models to deal with numerical data. However, there exist many data which contain numerical attributes and missing values simultaneously. We propose, in this paper, an extended rough set model, i.e. tolerance-fuzzy rough set model to deal with this type of data characterized with numerical attributes and missing values, that is, incomplete numerical data. Discernibility matrices and discernibility functions for incomplete numerical information systems and incomplete numerical decision systems are defined to compute reducts or relative reducts. Meanwhile, the relationship between the proposed tolerance-fuzzy rough set model and the tolerance rough set model is also examined. It is shown that the tolerance-fuzzy rough set model is an extension of the tolerance rough set model. Finally, uncertainty measurement is also investigated. It is suggested that the proposed tolerance-fuzzy rough set model provide an optional approach to incomplete numerical data. © 2013 Elsevier Inc. All rights reserved.

Cao C.,Hangzhou Normal University | Zhang F.,Zhejiang University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The electronic structure of the vacancy-ordered K0.5Fe 1.75Se2 iron-selenide compound (278 phase) is studied using the first-principles density functional method. The ground state of the 278 phase is stripelike antiferromagnetic, and its bare electron susceptibility shows a large peak around (π,π) in the folded Brillouin zone. Near the Fermi level, the density of states is dominated by the Fe-3d orbitals, and both electronlike and holelike Fermi surfaces appear in the Brillouin zone. An unfolded band structure shows limited similarities to a hole-doped 122 phase. With 0.1e electron doping, the susceptibility peak is quickly suppressed and broadened, while the two dimensionality of the electronlike Fermi surfaces is greatly enhanced, resulting in a better nesting behavior. Our study should be relevant to the recently reported superconducting phase K0.5+xFe 1.75+ySe2 with both x and y being very tiny. © 2013 American Physical Society.

Jie S.,Zhejiang University | Diaconescu P.L.,University of California at Los Angeles
Organometallics | Year: 2010

A comparison between the reactivity behavior of yttrium and lutetium benzyl complexes supported by a pyridine diamide, on one hand, and by a ferrocene diamide, on the other hand, toward aromatic N-heterocycles, such as 1-methylimidazole, isoquinoline, acridine, and 2-picoline, is presented. The ring opening of 1-methylimidazole by the pyridine-diamide complexes was observed, analogously to the ring opening of the same substrate by group 3 benzyl complexes supported by the ferrocenediamide ligand. Also, analogous products were observed in the reactions with 2-picoline and isoquinoline. However, when acridine was employed, different products were obtained for the two metal centers: alkyl transfer for yttrium and ortho-metalation for lutetium. © 2010 American Chemical Society.

Wang Y.,Zhejiang University
The Journal of bone and joint surgery. American volume | Year: 2013

Prior studies have suggested that vertebral end plate morphometrics and lesions may play a role in disc degeneration. However, most prior end plate studies have been based on radiographic images, and findings of associations between end plate morphometrics (measurements of size and shape) and disc degeneration remain controversial. The present study investigated the prevalence of vertebral end plate lesions and determined end plate morphometrics through direct measurements of cadaveric spines, and it examined the association of these factors with disc degeneration. We studied 600 vertebral end plates and 313 intervertebral discs from the cadaveric lumbosacral spines of seventy-six men (mean age, fifty-one years). Discography was performed to evaluate disc degeneration as indicated by disruption of the anulus fibrosus. The shape of the vertebral end plate and the presence of any lesions were visually evaluated. Lesions were rated as absent, small to moderate, or large. In addition, each end plate was digitized to quantify its area, circularity, and concavity. The association of end plate morphometrics and lesions with disc degeneration was examined. Vertebral end plate lesions were found in 72% (fifty-five) of the seventy-six lumbar spines and in 32.8% (197) of the 600 end plates. The presence of end plate lesions was associated with disc degeneration, with larger lesions being associated with more severe disc degeneration (odds ratio, 2.31 for small to moderate lesions [p < 0.01] and 3.54 for large lesions [p < 0.001]). Greater end plate area was also associated with more severe disc degeneration (odds ratio, 1.2 per cm2 [p < 0.05]). Vertebral end plate lesions were common and were associated with adjacent disc degeneration, with greater lesion size being associated with more severe disc degeneration. End plate morphometrics, particularly greater end plate size, may also play a role in the pathogenesis of disc degeneration.

Chen B.,University of Texas at San Antonio | Xiang S.,University of Texas at San Antonio | Qian G.,Zhejiang University
Accounts of Chemical Research | Year: 2010

Molecular recognition, an important process in biological and chemical systems, governs the diverse functions of a variety of enzymes and unique properties of some synthetic receptors. Because molecular recognition is based on weak interactions between receptors and substrates, the design and assembly of synthetic receptors to mimic biological systems and the development of novel materials to discriminate different substrates for selective recognition of specific molecules has proved challenging. The extensive research on synthetic receptors for molecular recognition, particularly on noncovalent complexes self-assembled by hydrogen bonding and metal-organic coordination, has revealed some underlying principles. In particular, these studies have demonstrated that the shapes of the supramolecular receptors play significant roles in their specific and selective recognition of substrates: receptors can offer concave surfaces that complement their convex targets. This Account describes our research to develop a synthetic molecular recognition platform using porous metal-organic frameworks (MOFs). These materials contain functional pores to direct their specific and unique recognition of small molecules through several types of interactions: van der Waals interactions of the framework surface with the substrate, metal-substrate interactions, and hydrogen bonding of the framework surface with the substrate. These materials have potential applications for gas storage, separation, and sensing. We demonstrate a simple strategy to construct a primitive cubic net of interpenetrated microporous MOFs from the self-assembly of the paddle-wheel clusters M2(CO 2)4 (M = Cu2+, Zn2+, and Co 2+) with two types of organic dicarboxylic acid and pillar bidentate linkers. This efficient method allows us to rationally tune the micropores to size-exclusively sort different small gas molecules, leading to the highly selective separation and purification of gases. By optimizing the strong interactions between open metal sites within porous MOFs and gas molecules such as hydrogen and acetylene, we have developed several MOF materials with extraordinary acetylene storage capacity at room temperature. We have also immobilized Lewis acidic and basic sites into luminescent porous MOFs to recognize and sense neutral and ionic species. Using the strategy to systematically immobilize different open metal sites within porous MOFs from the metalloligand precursors, we have developed the first microporous mixed-metal-organic framework (M′MOF) with enhanced affinity for hydrogen molecules, which successfully separated D2 from H2 using kinetic isotope quantum molecular sieving. Because we can functionalize the pores to direct their specific recognition of small molecules, the emerging porous MOFs serve as novel functional materials for gas storage, separation, heterogeneous catalysis, and sensing. © 2010 American Chemical Society.

We present in this work the theoretical aspect and numerical implementation of new enriched finite elements with smeared-embedded softening hinges for the analysis of Timoshenko and Euler-Bernoulli beams at failure. On one hand, similarly to the embedded hinge model, the softening hinge is described by a cohesive model between the stress resultants and the displacement jumps. On the other hand, the stress field in the element is evaluated from a constitutive relation at the cross-section level as in the classical smeared hinge model. The crucial point is the introduction of a consistent inelastic strain field dependent on both the interpolation scheme (not merely the characteristic length) of underlying finite elements and the hinge mode of interested. Furthermore, the traction continuity condition is enforced in strong form. Based on the irreversible thermodynamics, a multisurface model for the softening hinge and an inelastic constitutive relation for the cross-section of the beam are then established. Particularly, the displacement jumps are regarded as internal variables and can be determined at the material point level of the softening hinge. Therefore, it is not necessary to introduce the ad hoc penalty elastic stiffness, the extra degrees of freedom or the static condensation at the element level as in the embedded hinge model. Besides the above characteristics, the proposed method also defines a very convenient framework for its numerical implementation. Standard finite elements of beams/rods and well-developed algorithms for inelastic material models can be straightforwardly employed with minor modifications. Several representative numerical examples are presented, verifying that the proposed model is mesh-size objective, stress-locking free and frame invariant owing to its correct resolution of the kinematics and statics of the softening hinge. © 2013 Elsevier Ltd. All rights reserved.

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.

Peng H.,Anhui University of Science and Technology | Tian Z.,Anhui University of Science and Technology | Tian Z.,Zhejiang University
Trends in Immunology | Year: 2015

Recent studies have identified a population of liver-resident innate lymphoid cells (ILCs) that, based on the expression of certain phenotypic markers, were termed 'liver-resident NK cells' and considered to be a new subset of conventional natural killer (cNK) cells. However, different transcriptional networks control the development of liver-resident NK cells and cNK cells and, furthermore, these cells exhibit features that characterize mucosal ILC1s. Here, we review findings providing insight into the origin, phenotype, and function of liver-resident NK cells, and discuss these in the context of the current understanding of lineage relations of ILC subsets. We propose that the similarities between liver-resident NK cells and mucosal ILC1s should be considered when revising the categorization framework for these cells, and discuss implications of this revision for other tissue-specific NK cells. © 2015 Elsevier Ltd.

Huang M.-F.,Zhejiang University
Gongcheng Lixue/Engineering Mechanics | Year: 2013

This paper presents an integrated computer-based analysis and an optimal design method for the performance-based design of tall buildings under various levels of wind hazards. Performance-based wind engineering design framework for tall buildings has been proposed by considering three performance levels, i.e., life safety, damage reduction, habitability and operation under exposure to extreme wind events. The design wind speeds corresponding to multi-level wind hazards can be statistically estimated using meteorological wind speed data. Based on random vibration theory, the wind-induced responses of a tall building can be analyzed and formulated in the frequency domain for wind-induced performance assessment. A rigorously derived Optimality Criteria (OC) method is to be developed for achieving the optimal structural design solution of a tall building satisfying multiple wind-resistant performance constraints, i.e., the element strength, the system drift and acceleration design constraints. The effectiveness and practicality of the optimal performance-based design technique are illustrated by a 40-storey residential building with complex 3D mode shapes. Results have shown that the automated design optimization technique provides a powerful tool for multi-level performance-based design of wind sensitive tall building structures.

Wan R.,Zhejiang University
Nonlinear Analysis: Real World Applications | Year: 2016

In this paper, we obtain the uniqueness of the 2D MHD equations, which fills the gap of recent work by Chemin et al. (2015). © 2015 Published by Elsevier Ltd.

Smad proteins are central mediators in the canonical transforming growth factor-β (TGF-β) signaling pathway in mammalian cells. We report here that bromodomain-containing protein 7 (BRD7) functions as a novel transcription coactivator for Smads in TGF-β signaling. BRD7 forms a TGF-β inducible complex with Smad3/4 through its N-terminal Smad-binding domain. BRD7 simultaneously binds to acetylated histones to promote Smad-chromatin association, and associates with histone acetyltransferase p300 to enhance Smad transcriptional activity. Ectopic expression of BRD7, but not its mutants defective in Smad binding, enhances TGF-β transcriptional, tumor-suppressing and epithelial-mesenchymal transition responses. Conversely, depletion of BRD7 inhibits TGF-β responses. Thus, our study provides compelling evidence for a new function of BRD7 in fine-tuning TGF-β physiological responses.Oncogene advance online publication, 6 June 2016; doi:10.1038/onc.2016.204. © 2016 Macmillan Publishers Limited

Zhao F.D.,Zhejiang University
Orthopaedic surgery | Year: 2012

To review and analyze cage migration and related risk factors in patients who have undergone transforaminal lumbar interbody fusion (TLIF). A retrospective study was conducted to review the complications of cage migration in 512 patients who had undergone a TLIF procedure from January 2010 to June 2011 in five spinal centers. In all, 263 men and 249 women with a mean age of 54.7 years were included. All patients were followed up at 3, 6 and 12 months after the procedure. The clinical outcomes were evaluated by visual analogue scores, the Oswestry disability index, plain radiography and three-dimensional CT scanning to analyze the incidence of, and risk factors related to, cage migration. Cage migration was found in 6 of the 512 patients (1.17%). Significant differences were found between all pairs of centers. Different shapes and sizes of cages had different incidences of migration. Analysis showed that rectangular-shaped cages had a significantly greater incidence of cage migration (3.11%, 5/161) than did kidney-shaped cages (0.28%, 1/351; P < 0.05). Small cages had a tendency to more frequent post-operative cage migration (5.13%, 4/78) than did large cages (0.46%, 2/434; P < 0.05). Double segment TLIF cages migrated more frequently (5.75%, 5/87) than did mono-segment cages (0.24%, 1/425; P < 0.05)). Furthermore, when the adjacent endplates were of linear type, the cages migrated much more frequently (3.50%) than when they were of concave-concave type (0.27%; P < 0.05). Cage size, shape, number of fused segments and adjacent endplate shape might be risk factors for cage migration in addition to surgical technique, disc height and bone mineral density. © 2012 Tianjin Hospital and Wiley Publishing Asia Pty Ltd.

Ren Z.,Zhejiang University | Shakhnarovich G.,Toyota USA
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2013

We propose a hierarchical segmentation algorithm that starts with a very fine over segmentation and gradually merges regions using a cascade of boundary classifiers. This approach allows the weights of region and boundary features to adapt to the segmentation scale at which they are applied. The stages of the cascade are trained sequentially, with asymetric loss to maximize boundary recall. On six segmentation data sets, our algorithm achieves best performance under most region-quality measures, and does it with fewer segments than the prior work. Our algorithm is also highly competitive in a dense over segmentation (super pixel) regime under boundary-based measures. © 2013 IEEE.

Wu D.,National University of Ireland | Sun D.-W.,National University of Ireland | He Y.,Zhejiang University
Food Chemistry | Year: 2014

This study developed a pushbroom visible and near-infrared hyperspectral imaging system in the wavelength range of 400-1758 nm to determine the spatial distribution of texture profile analysis (TPA) parameters of salmon fillets. Six TPA parameters (hardness, adhesiveness, chewiness, springiness, cohesiveness, and gumminess) were analysed. Five spectral features (mean, standard deviation, skew, energy, and entropy) and 22 image texture features obtained from graylevel co-occurrence matrix (GLCM) were extracted from hyperspectral images. Quantitative models were established with the extracted spectral and image texture signatures of samples based on partial least squares regression (PLSR). The results indicated that spectral features had better ability to predict TPA parameters of salmon samples than image texture features, and Spectral Set I (400-1000 nm) performed better than Spectral II (967-1634 nm). On the basis of the wavelengths selected by regression coefficients of PLSR models, instrumental optimal wavelengths (IOW) and predictive optimal wavelengths (POW) were further chosen to reduce the high dimensionality of the hyperspectral image data. Our results show that hyperspectral imaging holds promise as a reliable and rapid alternative to traditional universal testing machines for measuring the spatial distribution of TPA parameters. © 2013 Elsevier Ltd. All rights reserved.

Zhang L.,Zhejiang University | Hurley W.G.,National University of Ireland | Wolfle W.H.,Convertec Ltd.
IEEE Transactions on Power Electronics | Year: 2011

Maximum power transfer in solar microgrid applications is achieved by impedance matching with a dcdc converter with maximum power point tracking by the incremental conductance method. Regulation and dynamic control is achieved by operating with continuous conduction. It can be shown that under stable operation, the required output inductor has an inductance versus current characteristic, whereby the inductance falls off with increasing current, corresponding to increasing incident solar radiation. This paper describes how a variable inductor whereby the inductor core progressively saturates with increasing current meets this requirement and has the advantage of reducing the overall size of the inductor by up to 75 and increases the operating range of the tracker to recover solar energy at low solar levels. © 2011 IEEE.

Song Z.-Z.,Zhejiang University
International Journal of Cardiology | Year: 2010

A 35-year-old man admitted with iterative extremities edema for three months and mild chest complaint associated with activity without chest distress for five days. He underwent an initial 2DE that did not confirm HVM/NVM and 3DE that strengthened the diagnosis of HVM/NVM. The limitations of 2DE may lead to misinterpretation of prominent trabeculations as "false tendons," and may also lead to underestimation of the severity of HVM/NVM. In contrast to 2DE, 3DE provides for pyramid-shaped datasets that encompass the entire right ventricular. Specifically, right ventricular can be sectioned in userselected planes and an unlimited number and angles of such planes can be used. Intracavitary echodensities that are suspicious for trabeculations can be tracked in multiple directions from base to apex. To our knowledge, this is the first report on only right ventricular HVM/NVM associated with Ebstein's malformation. The leaflets of the tricuspid valve develop from endocardial cushion tissue and the myocardium. The tricuspid valve leaflets become freely movable after delamination of the tension apparatus within the myocardium. Although the coexistence of right ventricular HVM/NVM and Ebstein's malformation could be a coincidence, I believe that both defects could be caused by a developmental arrest of the right ventricular myocardium. That is to say, the genetic change that is responsible for Ebstein's anomaly also plays a role in the differentiation of the right myocardium. © 2008 Elsevier Ireland Ltd.

Zhu G.,Zhejiang University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

The CDF 3.7 sigma evidence of pure annihilation Bs→π+π- decays, if confirmed, would imply a large annihilation scenario in the QCD factorization approach. This is somewhat unexpected as the large annihilation scenario was disfavored in previous studies. In this Letter we reinvestigate the role of annihilation topology in QCD factorization. We find that it is not easy to reach the CDF central value of Bs→π+π- decays when other decay channels are considered. Our analysis also reveals that, for well-measured charmless B decays into two final pseudoscalar mesons, the QCD factorization predictions with large annihilation parameters show good agreement with the experimental data except Bs→K+K- and Bd→K0K̄0 decays. Though other possibilities cannot be excluded, this may indicate that the SU(3) flavor symmetry breaking should be taken into account for the annihilation topology. In addition, there are different annihilation topologies, so that somewhat different annihilation parameters may be chosen for different final states and different annihilation topologies. If so, the predictive power of the QCD factorization method may be rather limited for many decay channels. © 2011 Elsevier B.V.

Shao K.-N.,Zhejiang University | Zhang Z.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

Kerr/CFT correspondence exhibits many remarkable connections between the near-horizon Kerr black hole and a conformal field theory (CFT). Recently, Castro, Maloney, and Strominger showed that a hidden conformal symmetry exists in the solution space of a Kerr black hole. In this paper we investigate a rotating black hole with four independent U(1) charges derived from string theory which is known as the four-dimensional Cvetic-Youm solution, and we prove that the same hidden conformal symmetry also holds. We obtain the exact black hole entropy using the temperatures derived. The entropy and absorption cross section agree with the previous results and. In addition, we clarify a previous explanation on the temperatures of the Cvetic-Youm solution's dual CFT. This work provides more robust derivation of the hidden conformal symmetry of Kerr-like black holes and as well as Kerr/CFT correspondence. © 2011 American Physical Society.

Zhang J.,Zhejiang University
Industrial and Engineering Chemistry Research | Year: 2013

In this article, a decoupling approach is first formulated, and then a corresponding nonminimal state space predictive control is proposed. The proposed decoupling structure can avoid zero-pole cancellations between the decoupler and the process, and thus, realization is guaranteed. Consequently, a systematic design of nonminimal state space predictive control can be designed in terms of a SISO procedure. Simulation results of a typical multivariable process are provided to demonstrate the effectiveness of the proposed method. In addition, a closed-form transfer function representation that facilitates frequency analysis of the control system is also provided to give further insight into the proposed strategy. © 2013 American Chemical Society.

Dai D.,University of California at Santa Barbara | Dai D.,Zhejiang University | Bowers J.E.,University of California at Santa Barbara
Optics Express | Year: 2011

A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light can be coupled from the narrow input waveguide to the adjacent wide waveguide while the TE polarization goes through the coupling region without significant coupling. An ultra-short (<10μm-long) PBS is designed based on silicon-on-insulator nanowires and the length of the bent coupling region is as small as 4.5μm while the gap width is chosen as 200nm (large enough to simplify the fabrication). Numerical simulations show that the present PBS has a good fabrication tolerance for the variation of the waveguide width (more than ± 60nm) and a very broad band (∼200nm) for an extinction ratio of >10dB. © 2011 Optical Society of America.

Caldeira K.,Carnegie Institution for Science | Bala G.,Indian Institute of Science | Cao L.,Zhejiang University
Annual Review of Earth and Planetary Sciences | Year: 2013

Carbon dioxide emissions from the burning of coal, oil, and gas are increasing atmospheric carbon dioxide concentrations. These increased concentrations cause additional energy to be retained in Earth's climate system, thus increasing Earth's temperature. Various methods have been proposed to prevent this temperature increase either by reflecting to space sunlight that would otherwise warm Earth or by removing carbon dioxide from the atmosphere. Such intentional alteration of planetary-scale processes has been termed geoengineering. The first category of geoengineering method, solar geoengineering (also known as solar radiation management, or SRM), raises novel global-scale governance and environmental issues. Some SRM approaches are thought to be low in cost, so the scale of SRM deployment will likely depend primarily on considerations of risk. The second category of geoengineering method, carbon dioxide removal (CDR), raises issues related primarily to scale, cost, effectiveness, and local environmental consequences. The scale of CDR deployment will likely depend primarily on cost. © Copyright ©2013 by Annual Reviews. All rights reserved.

Yang X.,Zhejiang University | Zheng S.G.,Pennsylvania State University
Autoimmunity Reviews | Year: 2014

Interleukin-22 (IL-22) is a member of IL-10 family cytokines that is produced by many different types of lymphocytes including both those of the innate and adaptive immune systems. This includes activated T cells, most notably Th17 and Th22 cells, and NK cells, γδ T cells, LTi cells and LTi-like cells. IL-22 mediates its effects via the IL-22-IL-22R complex and subsequent Janus kinase-signal transducer and activators of transcription (JAK-STAT) signaling pathway. Recently accumulated evidence has indicated that IL-22 also plays an important role in the pathogenesis of many autoimmune diseases. In this review, we discuss the recent findings and advancement of the role for IL-22 in several autoimmune diseases, such as psoriasis, rheumatoid arthritis (RA), hepatitis, graft versus host disease (GHVD) and allergic diseases, implicating that target IL-22 may have a therapeutic potential in those autoimmune diseases. © 2014 Elsevier B.V.

Chen D.,Zhejiang Normal University | Chen D.,Zhejiang University
Applied Optics | Year: 2010

A novel cylindrical hybrid plasmonic waveguide is proposed to achieve subwavelength confinement of light. With a metal core surrounded by a silica layer and a silicon layer, the proposed cylindrical hybrid plasmonic waveguide can achieve a ring-structure mode profile at the operating wavelength (1550 nm). Most mode power locates in the silica layer with a nanoscale thickness (e.g., 50, 20, or even 5 nm), which is due to the effects of both a strong discontinuity of the normal component of the electric field at the silicon- silica interface and the exited surface plasmon wave at the silica-metal interface. Cylindrical hybrid plasmonic waveguides with different structure parameters are investigated and a relatively long propagation distance of tens of micrometers (or even hundreds of micrometers) is observed. © 2010 Optical Society of America.

Ge Z.,Zhejiang University
IEEE Transactions on Industrial Electronics | Year: 2015

In this paper, a Bayesian regularization mechanism is provided for automatically determining the number of latent variables in the probabilistic principal component regression (PPCR) model. Different from the unsupervised principal-component-analysis model, the response variable is incorporated for the supervision of selecting latent variables in the PPCR model. By introducing two hyperparameter vectors, the effectiveness of each latent variable can be well measured and controlled. For the mixture form of the PPCR model, a corresponding mixture Bayesian regularization strategy is further developed to control the dimensionality of latent variables. The expectation-maximization algorithm is employed for the parameter learning of both single and mixture Bayesian regularization models. Two probabilistic soft sensors are then developed for the online estimation of key variables in industrial processes, the performances of which are evaluated through two case studies. Compared to the single Bayesian regularization model, the mixture model shows stronger soft sensing abilities in nonlinear and multimode processes. © 1982-2012 IEEE.

Mo Q.,Zhejiang University | Shen Y.,Zhejiang Sci-Tech University
IEEE Transactions on Information Theory | Year: 2012

This paper demonstrates that if the restricted isometry constant δ K+1 of the measurement matrix A satisfies δ K+1 < 1/√K+1 then a greedy algorithm called Orthogonal Matching Pursuit (OMP) can recover every K-sparse signal x in K iterations from Ax. By contrast, a matrix is also constructed with the restricted isometry constant δ K+1 < 1/√K+1 such that OMP can not recover some K-sparse signal x in K iterations. This result positively verifies the conjecture given by Dai and Milenkovic in 2009. © 2012 IEEE.

Dai D.,University of California at Santa Barbara | Dai D.,Zhejiang University | Bowers J.E.,University of California at Santa Barbara
Optics Express | Year: 2011

A novel concept for an ultracompact polarization splitter-rotator is proposed by utilizing a structure combining an adiabatic taper and an asymmetrical directional coupler. The adiabatic taper structure is singlemode at the input end while it becomes multimode at the other end. When light propagates along the adiabatic taper structure, the TM fundamental mode launched at the narrow end is efficiently (close to 100%) converted to the first higher-order TE mode at the wide end because of the mode coupling between them. By using an asymmetrical directional coupler that has two adjacent waveguides with different core widths, the first higher-order TE mode is then coupled to the TE fundamental mode of the adjacent narrow waveguide. On the other hand, the input TE polarization does not change when it goes through the adiabatic taper structure. In the region of the asymmetrical directional coupler, the TE fundamental mode in the wide waveguide is not coupled to the adjacent narrow waveguide because of phase mismatch. In this way, TE- and TM- polarized light are separated while the TM fundamental mode is also converted into the TE fundamental mode. A design example of the proposed polarization splitter-rotator is given by using silicon-on-insulator nanowires and the total length of the device is less than 100μm. Furthermore, only a one-mask process is needed for the fabrication process, which is compatible with the standard fabrication for the regular photonic integrated circuits based on SOI nanowires. © 2011 Optical Society of America.

Zhu G.,Zhejiang University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

In this paper we discuss the excess gamma rays from the Galactic center, the WMAP haze and the CoGeNT and DAMA results in WIMPless models. At the same time we also investigate the low energy constraints from the anomalous magnetic moment of leptons and from some lepton flavor violating decays. It is found that, for scalar or vector WIMPless dark matter, neither the WMAP haze nor the CoGeNT and DAMA observations could be explained simultaneously with the excess gamma rays from the Galactic center. As to fermion WIMPless dark matter, it is only marginally possible to accommodate the CoGeNT and DAMA results with the excess gamma rays from the Galactic center with vector connector fields. On the other hand, only scalar connector fields could interpret the WMAP haze concerning the constraints of anomalous magnetic moment of leptons. Furthermore, if there is only one connector field for all the charged leptons, some lepton flavor violating decays could happen with too large branching ratios severely violating the experimental bounds. © 2011 American Physical Society.

Liu J.,Zhejiang University
International journal of gynecological cancer : official journal of the International Gynecological Cancer Society | Year: 2010

Hairy and enhancer of split 1 (Hes1) and Hes5 are target genes for the mammalian Notch pathway, which are highly expressed in epithelia in the process of embryogenesis or in neural stem cells, inhibit cell differentiation via the Notch-Hes-Hash signaling, and promote the survival of stem cells. Either Hes1 or Hes5 overactivation is likely to affect cell differentiation, thereby resulting in carcinogenesis. We transfected the diced small interference RNA into SiHa cells and detected cell differentiation and proliferation by immunocytochemistry, Western blot, and methyl thiazolyl tetrazolium assay. Knockdown of Hes1 and Hes5 would up-regulate the downstream gene Hash1, but not the upstream gene Notch1 in the Notch-Hes-Hash pathway. After Hes1/Hes5 RNA interference, expression of differentiation-associated proteins (including Nanog, stage-specific embryonic antigen 4, and tumor rejection antigen-1-60) was reduced, and the cell differentiation was promoted; meanwhile, the cell proliferation was inhibited, which was verified by detecting proliferation-associated proteins (eg, Ki-67, proliferating cell nuclear antigen) and methyl thiazolyl tetrazolium assay. Our findings suggest that Hes1/Hes5 gene would inhibit the cell differentiation via down-regulating Hash1 and promote the cell proliferation in cervical carcinoma cells; the cell differentiation and proliferation can be reversed simultaneously by Hes1/Hes5 knockdown using RNA interference.

Cao C.,Hangzhou Normal University | Dai J.,Hangzhou Normal University | Dai J.,Zhejiang University
Physical Review Letters | Year: 2011

The magnetic properties and electronic structure of (K,Tl) yFe1.6Se2 is studied using first-principles calculations. The ground state is checkerboard antiferromagnetically coupled blocks of the minimal Fe4 squares, with a large block-spin moment ∼11.2μB. The magnetic interactions could be modeled with a simple spin model involving both the inter- and intrablock, as well as the nearest-neighbor and next-nearest-neighbor couplings. The calculations also suggest a metallic ground state except for y=0.8 where a band gap ∼400-550meV opens, showing an antiferromagnetic insulator ground state for (K,Tl)0.8Fe1.6Se2. The electronic structure of the metallic (K,Tl)yFe1.6Se2 is highly three dimensional with unique Fermi surface structure and topology. These features indicate that the Fe-vacancy ordering is crucial to the physical properties of (K,Tl)yFe2-xSe2. © 2011 American Physical Society.

Liang W.,Zhejiang University
Medicine (United States) | Year: 2015

We describe and analyze the clinical course and imaging findings of a case of a renal inflammatory myofibroblastic tumor (IMT) that is similar to cystic renal cell carcinoma. "Solitary cysts" on the left kidney were found during a health examination of a 60-year-old female. The patient also had hypertension. She had undergone surgeries twice for limb trauma fracture and had no definite record of hepatitis. There was no tenderness with percussion of the kidney area or edema in the lower extremity. The renal function results, including serum creatinine, blood urea nitrogen, and blood urea, were within the normal range. No gross hematuria or microscopic hematuria was found. An 8.7cm×9.2cm mixed echogenic mass at the upper pole of the left kidney was observed with ultrasound, the majority of which was an anechoic mass that was slightly protruding from the renal capsule and had well-circumscribed borders. After a bolus injection of an ultrasound contrast agent, the mass had rapid enhancement with fast fading. An approximately 9.4 cm×10.1 cm round-like cyst lesion at the upper pole of the left kidney was revealed by computed tomography (CT) examination of the abdomen; it had edge finishing with well-circumscribed borders. The upper inner wall of the lesion was thick with crescentic soft tissue. The solid content had gradual enhancement on enhanced CT scans. A kidney tumor was considered based on the CT findings. Based on the preoperative examination, the left renal cystic masses were resected. Intraoperative frozen sections were used to further clarify the nature of the lesion, and no significantmalignant cells were observed; therefore, the kidney was not removed. The pathological diagnosis was renal IMT. After surgery, the patient recovered and did not have recurrence or metastasis over the course of long-term follow-up. CT images of our patient with renal cystic disease are categorized as Fuhrman grade IV and typically indicate the presence of malignant lesions. However, gradual enhancement of the solid content in our case is different fromtypical cystic renal cell carcinoma. The nature of the lesion was further identified using intraoperative frozen sections, which helped avoid unnecessary nephrectomy. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Zhao B.,Zhejiang University | Zhao B.,University of California at San Diego | Li L.,University of California at San Diego | Wang L.,University of California at San Diego | And 3 more authors.
Genes and Development | Year: 2012

Cell attachment to the extracellular matrix (ECM) is crucial to cell physiology such as polarity, motility, and proliferation. In normal cells, loss of attachment to the ECM induces a specific type of apoptosis, termed anoikis. Resistance to anoikis in cancer cells promotes their survival in circulation and dispersion to distant anatomic sites, leading to tumor metastasis. The Yes-associated protein (YAP) transcription coactivator is a human oncogene and a key regulator of organ size. The Hippo tumor suppressor pathway phosphorylates and inhibits YAP. However, little is known about the signals that regulate the Hippo pathway. Here we report that through cytoskeleton reorganization, cell detachment activates the Hippo pathway kinases Lats1/2 and leads to YAP phosphorylation and inhibition. The detachment-induced YAP inactivation is required for anoikis in nontransformed cells, whereas in cancer cells with deregulation of the Hippo pathway, knockdown of YAP and TAZ restores anoikis. Furthermore, we provided evidence that Lats1/2 expression level is indeed significantly downregulated in metastatic prostate cancer. Our findings provide a novel connection between cell attachment and anoikis through the Hippo pathway and have important implications in cancer therapeutics. © 2012 by Cold Spring Harbor Laboratory Press.

Zhan L.-L.,Zhejiang University
Trends in Evolutionary Biology | Year: 2013

Alternative splicing, allowing multiple mRNAs to be generated from a single gene, is a major source of proteome diversity in eukaryotes. Intron retention (IR), one type of alternative splicing, is the complete retention of an intron in a mature transcript. IR is believed to be associated with failure of the recognition of weak splice sites flanking introns. Mutations in DNA sequences, including point mutations and sequence insertions or deletions, can be at the origin and evolution of IR. The strength of weaker splice sites is the main cause of IR, but some cis-regulatory elements and trans-regulatory factors can also play crucial roles in regulating IR. IR can result in the regulation of gene expression and may contribute to increase protein diversity. IR has been shown to occur in a variety of diseases, and it frequently leads to aberrant splicing. © L.-L. Zhan, 2013 Licensee PAGEPress, Italy.

Chen G.,Zhejiang University
Advances in experimental medicine and biology | Year: 2013

Daily exposure to extremely low frequency magnetic fields (ELF MF) in the environment has raised public concerns on human health. Epidemiological studies suggest that exposure to ELF MF might associate with an elevated risk of cancer and other diseases in humans. To explain and/or support epidemiological observations, many laboratory studies have been conducted to elucidate the biological effects of ELF MF exposure and the underlying mechanisms of action. In order to reveal the global effects of ELF MF on protein expression, the proteomics approaches has been employed in this research field. In 2005, WHO organized a Workshop on Application of Proteomics and Transcriptomics in electromagnetic fields (EMF) Research in Helsinki, Finland to discuss the related problems and solutions. Later the journal Proteomics published a special issue devoted to the application of proteomics to EMF research. This chapter aims to summarize the current research progress and discuss the applicability of proteomics approaches in studying on ELF MF induced biological effects and the underlying mechanisms.

Zhou X.,Zhejiang University
Annual Review of Phytopathology | Year: 2013

Begomoviruses are numerous and geographically widespread viruses that cause devastating diseases in many crops. Monopartite begomoviruses are frequently associated with betasatellites or alphasatellites. Both betasatellite and alphasatellite DNA genomes are approximately half the size of begomovirus DNA genomes. Betasatellites are essential for induction of typical disease symptoms. The βC1 genes encoded by the betasatellites have important roles in symptom induction, in suppression of transcriptional and posttranscriptional gene silencing, and they can affect jasmonic acid responsive genes. Host plants of begomoviruses have evolved diverse innate defense mechanisms against the βC1 protein to counter these challenges. Alphasatellites have been identified mainly in monopartite begomoviruses that associate with betasatellites and have no known contributions to pathogenesis of begomovirus-betasatellite disease complexes. Applications of current molecular tools are facilitating viral diagnosis and the discovery of novel species of geminiviruses and satellite DNAs and are also advancing our understanding of the global diversity and evolution of satellite DNAs. © Copyright ©2013 by Annual Reviews. All rights reserved.

To investigate the potential preventive effects of metformin on non-alcoholic fatty liver disease (NAFLD) and roles of phospholipase A2/lysophosphatidylcholine pathway in hepatocyte lipoapoptosis in a rat NAFLD model induced by high-fat diet. Male SD rats (n = 36) were randomly divided into three groups with 12 rats in each and treated with different diet and drugs: group I: ordinary diet, group II: high-fat diet, group III: high-fat diet and metformin. Ten weeks later, the rats were sacrificed and their body weight and liver weight were obtained, serum lipid metabolic indexes, insulin resistance indexes and secretory phospholipase A2 (sPLA2), lysophosphatidylcholine (LPC) levels and other parameters were measured. Phospholipase A2 mRNA expression levels were measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR). In addition, the histological changes of liver tissue were analyzed. Compared to ordinary diet group, the rat's liver weight (g) (16.92 ± 2.49 vs. 12.16 ± 0.82), hepatic exponent (0.034 ± 0.004 vs. 0.026 ± 0.002), serum alanine aminotransferase (U/L) (45.43 ± 9.73 vs. 29.42 ± 6.73), triglyceride (mmol/L) (1.22 ± 0.24 vs. 0.85 ± 0.19), cholesterol (mmol/L) (2.00 ± 0.37 vs. 1.49 ± 0.33), lipoprotein(a) (mmol/L) (743.86 ± 32.19 vs. 648.42 ± 78.87), low-density lipoprotein (mmol/L) (1.31 ± 0.35 vs. 0.65 ± 0.22), insulin (mmol/L) (22.16 ± 5.16 vs. 16.86 ± 5.35), insulin resistance index(5.10 ± 1.45 vs. 3.59 ± 0.99), free fatty acid (mEq/L) (0.57 ± 0.10 vs. 0.35 ± 0.07), sPLA2 [μmol/(min·ml)] (0.130 ± 0.016 vs. 0.098 ± 0.024), lysophosphatidylcholine (μmol/L) (707.26 ± 92.48 vs. 508.87 ± 96.50), leptin (pg/ml (80.08 ± 17.73 vs. 65.11 ± 14.09), liver triglyceride (mg/g) (13.57 ± 0.65 vs. 12.03 ± 1.14), cholesterol (mg/g) (2.19 ± 0.15 vs. 1.94 ± 0.12) (P < 0.05) were significantly increased in high-fat diet group. Moreover, degree of hepatic steatosis was significantly higher and sPLA2 mRNA expression was also significantly increased. Secondly, in comparison with high-fat diet group, early metformin treatment significantly reduced the rat's body weight (g) (394.40 ± 33.10 vs. 491.86 ± 26.45), liver weight (g) (13.24 ± 1.16 vs. 16.92 ± 2.49), serum alanine aminotransferase (U/L) (30.40 ± 4.50 vs. 45.43 ± 9.73), triglyceride (mmol/L) (0.75 ± 0.19 vs. 1.22 ± 0.24), cholesterol (mmol/L) (1.61 ± 0.38 vs. 2.00 ± 0.37), insulin (mmol/L) (16.96 ± 5.60 vs. 22.16 ± 5.16), insulin resistance index (3.75 ± 1.41 vs. 5.10 ± 1.45), sPLA2 [μmol/(min·ml)] (0.101 ± 0.009 vs. 0.130 ± 0.016), lysophosphatidylcholine (μmol/L) (549.92 ± 90.78 vs. 707.26 ± 92.48), liver triglyceride (mg/g) (11.23 ± 1.70 vs. 13.57 ± 0.65), cholesterol (mg/g) (1.97 ± 0.20 vs. 2.19 ± 0.15) (P < 0.05). Moreover, degree of hepatic steatosis was significantly lower and sPLA2 mRNA expression was also significantly decreased by metformin. Thirdly, when compared to ordinary diet group, metformin could also significantly increase hepatic exponent (0.034 ± 0.004 vs. 0.026 ± 0.002) and low-density lipoprotein level (mmol/L) (0.96 ± 0.34 vs. 0.65 ± 0.22) (P < 0.05). However, it had no impact on hepatic steatosis and sPLA2 expression (P > 0.05). It was indicated that metformin has potent effects on improving lipid metabolism and insulin resistance in high-fat diet induced non-alcoholic fatty liver disease rat model. The liver protective mechanisms of metformin in non-alcoholic fatty liver disease may be contributed to down-regulation of secretory phospholipase A2 mRNA expression, decrease in serum secretory phospholipase A2, lysophosphatidylcholine, lower inflammatory response and protect mitochondrial function.

Lin S.S.,Zhejiang University | Lin S.S.,University of Manchester
Journal of Physical Chemistry C | Year: 2012

Two-dimensional (2D) atomic crystals, especially graphene, have received much attention. However, the main shortcoming of graphene is its zero band gap. Silicon carbide, composed of silicon and carbon, is a typical wurtzite compound semiconductor, with more than 250 alloy types. Herein, we give some evidence of the solution exfoliation of 2D SiC nanoflakes with thickness down to 0.5-1.5 nm. Transmission electron microscopy (TEM) and X-ray diffraction characterizations reveal that graphitic (0001)/(0001̄) SiC most possibly has been formed by sonication of wurtzite SiC. Graphene, which is also produced in this process, naturally forms the ultrathin substrate facilitating the TEM characterization of 2D SiC. The mechanism of this exfoliation process should be related to the surface reconstruction of wurtzite SiC into graphitic SiC. Photoluminescence spectra show a strong light-emitting ability and a quantum-confinement-induced emission peak at 373 nm for these ultrathin SiC nanosheets. © 2012 American Chemical Society.

Introduction: Activated protein C (aPC) plays a pivotal role in modulating a severe inflammatory response and is thought to be beneficial for patients with sepsis. However, several meta-analyses of randomised controlled trials (RCTs) show that aPC is not significantly associated with improved survival in critically ill patients with sepsis. One suggestion is that these analyses simply ignored observational evidence. The present study aims to quantitatively demonstrate how observational data can alter the findings derived from synthesised evidence from RCTs by using a Bayesian approach. Methods and analysis: RCTs and observational studies investigating the effect of aPC on mortality outcome in critically ill patients with sepsis will be included. The quality of included RCTs will be assessed by using the Delphi list. Publication bias will be quantitatively analysed by using the traditional Egger regression test and the Begg rank correlation test. Observational data will be used as the informative prior for the distribution of OR. A power transformation of the observational data likelihood will be considered. Observational evidence will be down-weighted by a power of α which takes values from 0 to 1. Trial sequential analysis will be performed to quantify the reliability of data in meta-analysis adjusting significance levels for sparse data and multiple testing on accumulating trials. Trial registration number: PROSPERO (CRD42014009562).

Wang J.,Zhejiang University | Bayles K.W.,University of Nebraska Medical Center
Trends in Plant Science | Year: 2013

Programmed cell death (PCD) has well-established roles in the development and physiology of animals, plants, and fungi. Although aspects of PCD control appear evolutionarily conserved between these organisms, the extent of conservation remains controversial. Recently, a putative bacterial PCD protein homolog in plants was found to play a significant role in cell death control, indicating a conservation of function between these highly divergent organisms. Interestingly, these bacterial proteins are thought to be evolutionarily linked to the Bcl-2 family of proteins. In this opinion article, we propose a new unifying model to describe the relationship between bacterial and plant PCD systems and propose that the underlying control of PCD is conserved across at least three Kingdoms of life. © 2012 Elsevier Ltd.

Zhang L.,Zhejiang University | Zhang L.,Leiden University | Zhou F.,Leiden University | ten Dijke P.,Leiden University | ten Dijke P.,Uppsala University
Trends in Biochemical Sciences | Year: 2013

The transforming growth factor (TGF)-β and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways are used in cells to control numerous responses, including proliferation, apoptosis, and migration. TGF-β is known for its cytostatic effects in premalignant states and its pro-oncogenic activity in advanced cancers. The pro-cell survival response exerted by growth-factor-mediated activation of PI3K/AKT has been linked to stimulation of tumor formation. Both TGF-β receptor and PI3K/AKT pathways were initially modeled as linear signaling conduits. Although early studies suggested that these two pathways might counteract each other in balancing cell survival, emerging evidence has uncovered multiple modes of intricate signal integration and obligate collaboration in driving cancer progression. These new insights provide the rationale for exploring their dual targeting in cancer. © 2013 Elsevier Ltd.

Wu G.,Zhejiang Agriculture And forestry University | Wu G.,Zhejiang University
Journal of Genetics and Genomics | Year: 2013

MicroRNAs (miRNAs) are a class of about 20-24nt small non-coding RNAs that can regulate their target gene expression transcriptionally and posttranscriptionally. There are an increasing number of studies describing the identification of new components and regulatory mechanisms involved in the miRNA biogenesis and effector pathway as well as new functions of miRNAs in plant development. This review mainly focuses on the components involved in this pathway, and the developmental defects associated with the corresponding mutations. Some functions of important miRNAs in plant development, together with the modes of miRNA action, are also discussed in this review to describe the recent advance in this area. © 2013, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China.

Huang L.J.,Harbin Institute of Technology | Geng L.,Harbin Institute of Technology | Peng H.-X.,Zhejiang University
Progress in Materials Science | Year: 2015

Since the 1960s, it has been a common practice worldwide to pursue a homogeneous distribution of reinforcements within a matrix material, discontinuous metal matrix composites (DMMCs) in particular. Taking an overview of the worldwide activities in DMMC research, despite many favourable attributes such as improved specific strength, stiffness and superior wear resistance, DMMCs with a homogeneous microstructure tend to exhibit a very low room temperature damage tolerance even with a highly ductile matrix material such as aluminium. In this review, a range of uniquely multi-scale hierarchical structures have been successfully designed and fabricated by tailoring reinforcement distribution for DMMCs in order to obtain superior performance. A variety of specific microstructures that were developed in Al, Mg, Cu, Fe, Co and TiAl matrices indicate that there must be adequate plastic regions among the reinforcements to blunt or deflect cracks if one wants to toughen DMMCs. Following this path, aided by theoretical analyses, the most recent success is the design and fabrication of a network distribution of in situ reinforcing TiB whiskers (TiBw) in titanium matrix composites (TMCs), where a tailored three-dimensional (3D) quasi-continuous network microstructure displays significant improvements in mechanical properties. This resolves the brittleness surrounding TMCs fabricated by powder metallurgy. It is the large reinforcement-lean regions that remarkably improve the composite's ductility by bearing strain, blunting the crack and decreasing the crack-propagation rate. The fracture, strengthening and toughening mechanisms are comprehensively elucidated in order to further understand the advantages of such an inhomogeneous microstructure, and to justify the development of novel techniques to produce such inhomogeneous microstructures. This approach opens up a new horizon of research and applications of DMMCs and can be easily extended to general multi-phase composites with enhanced physical and mechanical properties. © 2015 Elsevier Ltd.

Different lifestyles, ranging from a saprophyte to a pathogen, have been reported in bacteria of one species. Here, we performed genome-wide survey of the ecological adaptation in four Burkholderia seminalis strains, distinguished by their origin as part of the saprophytic microbial community of soil or water but also including human and plant pathogens. The results indicated that each strain is separated from the others by increased fitness in medium simulating its original niche corresponding to the difference between strains in metabolic capacities. Furthermore, strain-specific metabolism and niche survival was generally linked with genomic variants and niche-dependent differential expression of the corresponding genes. In particular, the importance of iron, trehalose and d-arabitol utilization was highlighted by the involvement of DNA-methylation and horizontal gene transfer in niche-adapted regulation of the corresponding operons based on the integrated analysis of our multi-omics data. Overall, our results provided insights of niche-specific adaptation in bacteria.The ISME Journal advance online publication, 9 February 2016; doi:10.1038/ismej.2015.251. © 2016 International Society for Microbial Ecology

Gao S.,Zhejiang University | Xiao X.,Tsinghua University
Optics Communications | Year: 2012

We theoretically present and experimentally demonstrate all-optical wavelength multicasting based on cascaded four-wave mixing (FWM) in highly nonlinear fibers only using a single pump. The cascaded FWM effect is analyzed based on the sum amplitude method, which overcomes the limitation of the number of analyzed idlers, and the performance of the wavelength multicasting is evaluated. By using a continuous wave pump and a pulse train as the signal, multiple-order idlers are experimentally generated and the patterns of 6 multicasting channels are measured. Regardless of the dynamic region of the tunable filter, this method has the potential to realize more multicasting channels, especially when higher pump and signal powers are used. © 2011 Elsevier B.V. All rights reserved.

Dong D.,Australian Defence Force Academy | Dong D.,Zhejiang University | Petersen I.R.,Australian Defence Force Academy
Automatica | Year: 2012

In [Dong, D. and Petersen, I.R. (2012). Sliding mode control of two-level quantum systems. Automatica, 48, 725-735], a sliding mode control approach has been proposed for two-level quantum systems to deal with bounded uncertainties in the system Hamiltonian. This paper further extends these results in two directions. One extension is to consider the effect of uncertainties during the process of driving the system's state back to the sliding mode domain from outside and we propose two approaches to accomplish this control task. The other extension generalizes the previous design approach to consider uncertainties described as perturbations in the free Hamiltonian. © 2012 Elsevier Ltd. All rights reserved.

Zhou Y.,Zhejiang University | Lee P.A.,Massachusetts Institute of Technology
Physical Review Letters | Year: 2011

Several experimental candidates for quantum spin liquids have been discovered in the past few years which appear to support gapless fermionic S=12 excitations called spinons. The spinons may form a Fermi sea coupled to a U(1) gauge field, and may undergo a pairing instability. We show that despite being charge neutral, the spinons couple to phonons in exactly the same way that electrons do in the long wavelength limit. Therefore, we can use sound attenuation to measure the spinon mass and lifetime. Furthermore, transverse ultrasonic attenuation is a direct probe of the onset of pairing because the Meissner effect of the gauge field causes a "rapid fall" of the attenuation at Tc in addition to the reduction due to the opening of the energy gap. This phenomenon, well known in clean superconductors, may reveal the existence of the U(1) gauge field. © 2011 American Physical Society.

Zhu G.,Zhejiang University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

Recently Nelson et al. proposed an interesting flavor symmetric model to account for the top quark forward-backward asymmetry and the dijet anomaly at CDF simultaneously with just three parameters: a coupling constant of order one, and two scalar masses of 160 GeV and 220 GeV. However these fiducial values of the parameters lead to the branching ratio of a almost pure penguin B→ΠK decay about one hundred times larger than the experimental results. Consider also the precision electroweak constraints, the scalar masses should be at least around 500 GeV. Actually with the coupling constant larger than one, it is impossible to explain either of the two CDF measurements consistently in this model. But one may raise the charged scalar mass to, for example, 250 GeV and reduce the coupling strength to 0.6 to meet the B physics constraints. With this parameter set, the Wjj cross section is found to be in the right range. But due to the scalar mass splitting, its correction to T-parameter is about 3 Σ away from the precision electroweak constraints. In addition, the top quark forward-backward asymmetry should be well below 0.1 with this small coupling constant. © 2011 Elsevier B.V.

Dong D.,Australian Defence Force Academy | Dong D.,Zhejiang University | Petersen I.R.,Australian Defence Force Academy
Automatica | Year: 2012

This paper proposes a robust control method based on sliding mode design for two-level quantum systems with bounded uncertainties. An eigenstate of the two-level quantum system is identified as a sliding mode. The objective is to design a control law to steer the system's state into the sliding mode domain and then maintain it in that domain when bounded uncertainties exist in the system Hamiltonian. We propose a controller design method using the Lyapunov methodology and periodic projective measurements. In particular, we give conditions for designing such a control law, which can guarantee the desired robustness in the presence of the uncertainties. The sliding mode control method has potential applications to quantum information processing with uncertainties. © 2012 Elsevier Ltd. All rights reserved.

Wang H.,Deakin University | Xue Y.,Deakin University | Ding J.,Defence Science and Technology Organisation, Australia | Feng L.,Zhejiang University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

A fabric coating prepared from a homogeneous mixture of fluorinated-decyl polyhedral oligomeric silsesquioxane and hydrolyzed fluorinated alkyl silane shows remarkable self-healing superhydrophobic and superoleophobic properties and excellent durability against UV light, acid, repeated machine washes, and severe abrasion (see picture). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Chinese mitten crab Eriocheir sinensis belongs to the Class Crustacea, Decapoda, Brachyura. The spermatozoon of this species is of aflagellated type, it has a spherical acrosome surrounded by the cup-shaped nucleus, which are unique to brachyurans. For the past several decades, studies on the spermatogenesis of the mitten crab mainly focus on the morphology. Compared with the extensive study of molecular mechanism of spermatogenesis in mammals, relatively less information is available in crustacean species. Myosin Va, a member of Class V myosin, has been implicated in acrosome biogenesis and vesicle transport during spermatogenesis in mammals. In the present study we demonstrate the expression and cellular localization of myosin Va during spermatogenesis in E. sinensis. Western blot demonstrated that myosin Va is expressed during spermatogenesis. Immunocytochemical and ultrastructural analyses showed that myosin Va mainly localizes in the cytoplasm in spermatocytes. At the early stage of spermiogenesis, myosin Va binds to the endoplasmic reticulum vesicle (EV) and proacrosomal granule (PG). Subsequently, myosin Va localizes within the proacrosomal vesicle (PV) formed by PG and EV fusion and locates in the membrane complex (MC) at the mid spermatid stage. At the late spermatid stage, myosin Va is associated with the shaping nucleus and mitochondria. In mature spermatozoon, myosin Va predominates in acrosomal tubule (AT) and nucleus. Our study demonstrates that myosin Va may be involved in acrosome biogenesis and nuclear morphogenesis during spermatogenesis in E. sinensis. Considering the distribution and molecular characteristics of myosin Va, we also propose a hypothesis of AT formation in this species. It is the first time to uncover the role of myosin Va in crustacean spermatogenesis.

Lin H.,Zhejiang University
CAD Computer Aided Design | Year: 2010

The geometric interpolation algorithm is proposed by Maekawa et al. in [Maekawa T, Matsumoto Y, Namiki K. Interpolation by geometric algorithm. Computer-Aided Design 2007;39:313-23]. Without solving a system of equations, the algorithm generates a curve (surface) sequence, of which the limit curve (surface) interpolates the given data points. However, the convergence of the algorithm is a conjecture in the reference above, and demonstrated by lots of empirical examples. In this paper, we prove the conjecture given in the reference in theory, that is, the geometric interpolation algorithm is convergent for a blending curve (surface) with normalized totally positive basis, under the condition that the minimal eigenvalue λmin (Dk) of the collocation matrix Dk of the totally positive basis in each iteration satisfies λmin (Dk) ≥ α > 0. As a consequence, the geometric interpolation algorithm is convergent for Bézier, B-spline, rational Bézier, and NURBS curve (surface) if they satisfy the condition aforementioned, since Bernstein basis and B-spline basis are both normalized totally positive. © 2010 Elsevier Ltd. All rights reserved.

Yi K.,John Innes Center | Yi K.,Zhejiang University | Menand B.,John Innes Center | Menand B.,Aix - Marseille University | And 3 more authors.
Nature Genetics | Year: 2010

Postmitotic cell growth defines cell shape and size during development. However, the mechanisms regulating postmitotic cell growth in plants remain unknown. Here we report the discovery of a basic helix-loop-helix (bHLH) transcription factor called RSL4 (ROOT HAIR DEFECTIVE 6-LIKE 4) that is sufficient to promote postmitotic cell growth in Arabidopsis thaliana root-hair cells. Loss of RSL4 function resulted in the development of very short root hairs. In contrast, constitutive RSL4 expression programmed constitutive growth, resulting in the formation of very long root hairs. Hair-cell growth signals, such as auxin and low phosphate availability, modulate hair cell extension by regulating RSL4 transcript and protein levels. RSL4 is thus a regulator of growth that integrates endogenous developmental and exogenous environmental signals that together control postmitotic growth in root hairs. The control of postmitotic growth by transcription factors may represent a general mechanism for regulating cell size across diverse organisms. © 2010 Nature America, Inc. All rights reserved.

Li L.B.,Zhejiang University
Critical Care | Year: 2013

Critical care medicine in China has made great advances in recent decades. This has led to an unavoidable issue: end-of-life ethics. With advances in medical technology and therapeutics allowing the seemingly limitless maintenance of life, the exact time of death of an individual patient is often determined by the decision to limit life support. How to care for patients at the end of life is not only a medical problem but also a social, ethical, and legal issue. A lot of factors, besides culture, come into play in determining a person's ethical attitudes or behaviors, such as experience, education, religion, individual attributes, and economic considerations. Chinese doctors face ethical problems similar to those of their Western counterparts; however, since Chinese society is different from that of Western countries in cultural traditions, customs, religious beliefs, and ethnic backgrounds, there is a great difference between China and the Western world in regard to ethics at the end of life, and there is also a huge controversy within China. © 2013 BioMed Central Ltd.

Jiang Z.,Zhejiang University
European review for medical and pharmacological sciences | Year: 2013

Bacteria, funghi, viruses and protozoa can lead to neonatal sepsis. Neonatal sepsis is the leading cause of infectious disease onset and death in many neonates. To explore the major risk factors of early-onset neonatal sepsis and provide a scientific basis for strategies of early-onset neonatal sepsis prevention. A 1:4 matched case-control study was adopted and 147 cases of early-onset neonatal sepsis were enrolled. Conditional logistic regression model was used to analyze the univariate and multivariate data to estimate the odds ratio (OR) and the 95% confidence interval (95% CI). Univariate analysis shows that the impact factors on the occurrence of early-onset neonatal sepsis include the following: Maternal age > 35, mother having fixed occupation, mother of urban residence, abnormal fetal position, fetal times, parity, caesarean section, premature rupture of membranes, amniotic fluid volume abnormalities, pregnancy-induced hypertension, placental abnormalities, fetal distress, newborn gender, low birth weight infants, neonatal Apgar scoring at one and five minutes, neonatal jaundice, wet lung, anemia, IVH, and premature infant. Multivariate logistic regression analysis showed that maternal age > 35 (OR = 4.835, OR 95% CI = 1.170-19.981), cesarean section (OR = 0.103, OR 95% CI = 0.041-0.258), premature rupture of membranes (OR = 0.207, OR 95% CI = 0.078-0.547), premature infants (OR = 0.059, OR 95% CI = 0.010-0.329) and newborn jaundice (OR = 0.092, OR 95% CI = 0.021-0.404) were the factors of early-onset neonatal sepsis. Early-onset neonatal sepsis could be affected by multi-factors, and targeted prevention may reduce the incidence of early-onset neonatal sepsis rates.

The exiting automatic phase partition and phase-based process monitoring strategies are in general limited to single-mode multiphase batch processes. In this article, a concurrent phase partition and between-mode statistical modeling strategy (CPPBM) is proposed for online monitoring of multimode multiphase batch processes. First, the time-varying characteristics of batch processes are concurrently analyzed across modes so that multiple sequential phases are simultaneously identified for all modes. The feature is that both time-wise dynamics and mode-wise variations are considered to get the consistent phase boundaries. Then within each phase, between-mode statistical analysis is performed where one mode is chosen for the development of reference monitoring system and the relative changes from the reference mode to each alternative mode are analyzed. From the between-mode perspective, each of the original reference monitoring subspaces, including systematic subspace and residual subspace, are further decomposed into two monitoring subspaces for each alternative mode, which reveal two kinds of between-mode relative variations. The part which shows significant increases represents the variations that will cause alarm signals if the reference models are used to monitor the alternative modes, whereas the part that shows no increases will not issue alarms. By modeling and monitoring different types of between-mode relative variations, the proposed CPPBM method can not only efficiently detect faults but also offer enhanced process understanding. It is illustrated with a typical multiphase batch process with multiple modes. © 2013 American Institute of Chemical Engineers.

Lou M.,Zhejiang University | Caplan L.R.,Beth Israel Deaconess Medical Center
Annals of the New York Academy of Sciences | Year: 2010

Dolichoectasia (dilatative arteriopathy) describes marked elongation, widening, and tortuosity of arteries. The intracranial vertebral and basilar arteries are preferentially involved. Dolichoectatic arteries usually have an abnormally large external diameter and a thin arterial wall, with degeneration of the internal elastic lamina, multiple gaps in the internal elastica, thinning of the media secondary to reticular fiber deficiency, and smooth muscle atrophy. The most important clinical presentations of dilatative arteriopathy include acute brain ischemia; a progressive course related to compression of cranial nerves, the brain stem, or the third ventricle; and catastrophic outcome caused by vascular rupture. Flow in dilated arteries can become bidirectional, resulting in reduced antegrade flow and thrombus formation. Elongation and angulation of arteries can stretch and distort the orifices of arterial branches, leading to decreased blood flow, especially in penetrating branches. © 2009 New York Academy of Sciences.

Fang Z.,University of Queensland | Fang Z.,Zhejiang University | Bhandari B.,University of Queensland
Food Chemistry | Year: 2011

Bayberry juice was spray dried with maltodextrin (DE 10) as a carrier and then stored under different temperature and water activities (aw). The retention of the total phenolic content (TPC) and total anthocaynins (ACN) during the drying process were about 96% and 94%, respectively, suggesting spray drying was a satisfactory technique for drying heat sensitive polyphenols. Under an aw of 0.11-0.44, the TPC and ACN in bayberry powders decreased by about 6-8% and 7-27%, respectively, after 6 months storage at 4 °C; at 25 °C for the same storage period the decreases were between 6-9% and 9-37%, respectively, while at 40 °C the decreases were in the range 7-37% and 9-94%. The anthocyanin component was more readily degraded relative to other phenolic compounds. The results suggest that bayberry powder should be stored at less than 25 °C and aw of 0.33, on account of greater polyphenol stability under such conditions. © 2011 Elsevier Ltd. All rights reserved.

Wu B.,Zhejiang University
Current Topics in Medicinal Chemistry | Year: 2014

Tyrosinase is a multifunctional copper-containing enzyme widely distributed in plants and animals, which catalyzes both the hydroxylation of tyrosine into o-diphenols and the oxidation of o-diphenols into o-quinones. Tyrosinase is known to be a key enzyme for melanin biosynthesis in plants and animals. Tyrosinase inhibitors, therefore, can be clinically useful for the treatment of some dermatological disorders associated with melanin hyperpigmentation. They also find uses in cosmetics for whitening and depigmentation after sunburn. This review describes 236 compounds obtained from terrestrial and marine plants, animals, microorganisms and macrofungi which have been shown to inhibit tyrosinase. The mechanism of action of tyrosinase, together with the mode of action of inhibitors is described. The relative activities of the different compounds are recorded. The literature on plant-origin inhibitors is extensive, and their chemistry and biological activity have been intensively reviewed. This review will therefore be deliberately cover new classes of inhibitors from terrestrial and marine plants, animals, microorganisms and macrofungi, as well as the traditional classes. The present paper summarizes and discusses the scientific results on the discovery of natural tyrosinase inhibitors. © 2014 Bentham Science Publishers.

Zhao B.,Zhejiang University | Guan K.-L.,University of California at San Diego
Cell | Year: 2014

Tetraploid cells generated by abnormal cell division are often arrested during the cell cycle or cleared by apoptosis. Evasion of these defense mechanisms leads to genomic instability and tumorigenesis. In this issue, Ganem et al. report that extra centrosome-induced activation of the Hippo pathway kinase LATS2 is a key mechanism of tetraploidy-induced cell-cycle arrest. © 2014 Elsevier Inc.

MacCone L.,University of Pavia | Pati A.K.,Harish Chandra Research Institute | Pati A.K.,Zhejiang University
Physical Review Letters | Year: 2014

The Heisenberg-Robertson uncertainty relation expresses a limitation in the possible preparations of the system by giving a lower bound to the product of the variances of two observables in terms of their commutator. Notably, it does not capture the concept of incompatible observables because it can be trivial; i.e., the lower bound can be null even for two noncompatible observables. Here we give two stronger uncertainty relations, relating to the sum of variances, whose lower bound is guaranteed to be nontrivial whenever the two observables are incompatible on the state of the system. © 2014 American Physical Society.

Wang J.,Zhejiang University | Knowles P.J.,University of Cardiff
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

By explicit construction of counterexamples having the same eigenvalue spectrum of one-matrix, but different two-matrix, we show that density-matrix functionals for the electronic energy that are based solely on the eigenvalues of the one-matrix cannot be unique in functional representation of the two-matrix. The one-to-many mapping may be understood either through the number of independent parameters or the contraction relation. © 2015 American Physical Society.

Zhang Z.,Jiangnan University | Ding F.,Jiangnan University | Liu X.,Zhejiang University
Computers and Mathematics with Applications | Year: 2011

According to the hierarchical identification principle, a hierarchical gradient based iterative estimation algorithm is derived for multivariable output error moving average systems (i.e., multivariable OEMA-like models) which is different from multivariable CARMA-like models. As there exist unmeasurable noise-free outputs and unknown noise terms in the information vector/matrix of the corresponding identification model, this paper is, by means of the auxiliary model identification idea, to replace the unmeasurable variables in the information vector/matrix with the estimated residuals and the outputs of the auxiliary model. A numerical example is provided. © 2010 Elsevier Ltd. All rights reserved.

Wei B.,Beijing University of Technology | Zheng K.,Beijing University of Technology | Ji Y.,Beijing University of Technology | Zhang Y.,Beijing University of Technology | And 2 more authors.
Nano Letters | Year: 2012

We quantified the size-dependent energy bandgap modulation of ZnO nanowires under tensile strain by an in situ measurement system combining a uniaxial tensile setup with a cathodoluminescence spectroscope. The maximal strain and corresponding bandgap variation increased by decreasing the size of the nanowires. The adjustable bandgap for the 100 nm nanowire caused by a strain of 7.3% reached approximately 110 meV, which is nearly double the value of 59 meV for the 760 nm nanowire with a strain of 1.7%. A two-step linear feature involving bandgap reduction caused by straining and a corresponding critical strain was identified in ZnO nanowires with diameters less than 300 nm. The critical strain moved toward the high strain level with shrunken nanowires. The distinct size effect of strained nanowires on the bandgap variation reveals a competition between core-dominated and surface-dominated bandgap modulations. These results could facilitate potential applications involving nanowire-based optoelectronic devices and band-strain engineering. © 2012 American Chemical Society.

Liang C.Z.,Zhejiang University
The Journal of international medical research | Year: 2012

A systematic review to evaluate the role of surgery for treating degenerative scoliosis (DS) in terms of improved function (Oswestry Disability Index [ODI]) and correction of deformity (Cobb angle); safety outcomes included complication and repeat surgery rates. A search of the MEDLINE, ISI Web of Knowledge and Cochrane Library databases was performed. The methodological quality of each study was assessed according to standardized criteria and data were extracted. A total of 16 studies including 553 patients with DS met the eligibility criteria for inclusion. The mean ODI score at final follow-up was 36.0 ± 7.8 (304 patients) and the mean decrease in ODI was 23.3 ± 11.3 (302 patients). Mean reduction in curve angle (as a percentage of the original curve) was 48.5 ± 21.0% (527 patients). The overall incidence of complications was 49.0% (171 in 349 patients) and the rate of repeat surgery was 15.3% (61 in 398 patients). Despite a high incidence of complications and reoperations, surgery was an effective and reasonable treatment for DS, providing significant functional improvement and deformity correction.

Li H.,Zhejiang University
Zhonghua nei ke za zhi | Year: 2014

OBJECTIVE: To investigate the relationship between serum uric acid (UA) level and abdominal obesity or metabolic syndrome (MS).METHODS: A total of 875 subjects, with 350 males and 525 females, aged 40-65 years old, were enrolled in this study. The clinical and biochemical data were collected and MRI was used to assess the visceral and subcutaneous adipose tissues. The relationships between UA level and abdominal obesity or MS were analyzed, and the cut-off values of UA for abdominal obesity and MS were determined.RESULTS: Raised risks of abdominal obesity(OR = 4.35, 95%CI 1.91-9.90 in males; OR = 5.44, 95%CI 2.41-12.31 in females) and MS(OR = 4.47, 95%CI 2.08-9.62 in males; OR = 11.62, 95%CI 3.43-39.37 in females) were observed with the increase of UA level. The multiple logistic regression analysis showed that UA was an independent risk factor for hypertriglyceridemia(OR = 2.23, 95%CI 1.02-4.87 in males; OR = 3.04, 95%CI 1.49-6.23 in females) in all subjects and for abdominal obesity(OR = 3.23, 95%CI 1.32-7.91) and hypertension (OR = 2.35, 95%CI 1.37-4.05) in the females. Among the females, the regression line analyzed by simple correlation indicated that the UA level of 244.0 µmol/L was corresponded to the visceral adipose tissue area of 80 cm(2). The optimal cut-off point of UA for the diagnosis of MS was 258.8 µmol/L determined by the receiver operating characteristic curve.CONCLUSIONS: The level of UA is closely correlated with abdominal obesity and MS in the middle-aged Chinese. The elevated UA level is an independent risk factor for abdominal obesity and MS in the female.

Feng B.,Zhejiang University | Feng B.,Copenhagen University
Journal of High Energy Physics | Year: 2016

In this paper, by treating massive loop momenta as massless momenta in higher dimensions, we are able to treat all-loop scattering equations as tree ones. As an application of the new perspective, we consider the CHY-construction of bi-adjoint ϕ3 theory. We present the explicit formula for two-loop planar integrands. We discuss in details how to subtract various forward singularities in the construction. We count the number of terms obtained by our formula and by direct Feynman diagram calculation and find the perfect match, thus provide a strong support for our results. © 2016, The Author(s).

Wang F.,Zhejiang University | Higgins J.M.,Harvard University
Trends in Cell Biology | Year: 2013

The roles of post-translational histone modifications in regulating transcription and DNA damage have been widely studied and discussed. Although mitotic histone marks, particularly phosphorylation, were discovered four decades ago, their roles in mitosis have been out-lined only in the past few years. Here we aim to provide an integrated view of how histone modifications act as 'countermarks', 'landmarks', and 'bookmarks' to dis-place, recruit, and 'remember' the location of regulatory proteins during and shortly after mitosis. These capabil-ities allow histone marks to help downregulate inter-phase functions such as transcription during mitosis, to facilitate chromatin events required to accomplish chro-mosome segregation, and to contribute to the mainte-nance of epigenetic states through mitosis.

Swaab D.F.,An institute of the Royal Netherlands Academy of Arts and science | Bao A.-M.,Zhejiang University
Experimental Gerontology | Year: 2011

Our hypothesis is that there is 'wear and tear' in the brain, which is the basis of the process of aging, but that stimulation of brain function may slow down brain aging and diminish the risk for neurodegenerative diseases such as Alzheimer's disease (AD), possibly by activating repair mechanisms. Evidence supporting this hypothesis is presented in this review.During normal aging and in AD, cell loss is not as prominent a phenomenon as is often presumed. In fact, unaltered neuronal numbers have been reported in many brain areas in AD, e.g. in the nucleus basalis of Meynert (NBM) where the number of large neurons decreases while that of small neurons increases. Decreased neuronal activity is an essential characteristic of AD, and a substantial decrease of cerebral glucose metabolism may even precede cognitive impairments.Some hypothalamic neurons remain intact and active during the process of aging, others become even hyperactive, which may lead to disorders. Arginine vasopressin (AVP) levels were found to be higher in the elderly than in young subjects. There is an age-related, sex-dependent activation of the AVP neurons in the supraoptic nucleus (SON) and in the paraventricular nucleus (PVN), which may be the basis of analogous changes in the prevalence of hypertension and hyponatraemia in the elderly. No significant functional loss of magnocellular hypothalamic neurosecretory neurons were found in the SON or PVN in AD.The activity of the corticotrophin releasing hormone (CRH) neurons in the hypothalamic PVN is the basis for the activity of the hypothalamo-pituitary-adrenal (HPA) axis, which is activated during aging in a sex-dependent way, and even more activated in AD. The activated HPA axis is a risk for depression.Environmental stimulation increases brain reserve. An increase in time spent on intellectual activities was associated with a significant decrease in probability to get AD, and occupation has even a stronger indication of diminished risk for dementia.A series of observations showed that a dysfunctional clock may underlie the disordered rhythms in AD. Additional bright light improved the rest-activity rhythms, while giving bright light and/or melatonin to AD patients ameliorated the progression of cognitive and noncognitive symptoms. This implies that neurons affected by AD can still be reactivated if the right stimuli are applied. Unknown diffusible factors from the neural stem cells improve the survival of aged and degenerating neurons in postmortem human brain slice cultures. Gene therapy with nerve growth factor aimed at the NBM showed metabolic activation of various brain regions. A microarray study of the prefrontal cortex in the course of AD revealed an increased expression of genes related to synaptic activity and changes in plasticity during the very early pre-symptomatic stages, which is proposed to represent a coping mechanism against increased soluble β-amyloid levels.In brief, these examples of the 'use it or lose it' principle during the course of aging or AD now provide novel targets for the development of therapeutic strategies aiming at the prevention and treatment of AD. © 2010 Elsevier Inc.

Huang C.,George Washington University | Yu H.,Zhejiang University | Koplan J.P.,Emory University
The Lancet | Year: 2014

China has rapidly progressed through epidemiological and demographic transitions and is now confronting an increasing burden from non-communicable diseases and injuries. China could take advantage of what has been learnt about prevention and control of non-communicable diseases and injuries, which is well summarised in the WHO best buys (a set of affordable, feasible, and cost-effective intervention strategies in any resource setting), to improve individual and population health. Implementation of these strategies could allow China to exceed the incremental gains in decreasing non-communicable diseases and injury burdens of high-income countries, and greatly shorten the interval needed to achieve decreased morbidity and mortality in its population. With the lessons learnt from other countries and its own programmes and policies, China could provide a health model for the world. © 2014 Elsevier Ltd.

Li Y.,Zhejiang University | Ranieri M.,University of Florence
Computers and Education | Year: 2013

Over the last decades, the issue of digital divide has received particular attention from international bodies and researchers in Western countries. One of the main reasons for this growing interest is related to the implications that digital inequalities have for social development and particularly for education. Despite the relevance of the issue, there are still few studies on the digital divide in China and even less on Chinese K-12 schools' students. This paper aims at exploring the digital divide issues among Chinese children from an educational and social perspective. Four schools were selected, involving 658 students aged 10-14. Nine hypotheses on Internet inequality indicators (DiMaggio & Hargittai, 2001) and their possible outcomes were tested. The study found that: (1) students' Internet access at home is better than that at school; (2) compared with parents, teachers have more positive influence on students' Internet behaviour; (3) students from rural or migrant schools score lower on all the Internet inequality indicators (digital access, autonomy of use, social support, Internet use and self-efficacy) and are therefore more disadvantaged in Internet usage status than their urban peers; (4) there are no significant gender differences; (5) the more education parents have received, the better the conditions of their children according to the listed Internet inequality indicators; (6) the dimensions of the Internet inequality indicators (technical apparatus, autonomy of use, availability of social support, variation of use) are significantly correlated to students' Internet self-efficacy; (7) there is high correlation between students' Internet self-efficacy and their exploring behaviours of Internet use and their academic performance. Overall, these results are consistent with data from OECD countries and confirm that the digital divide represents a big social challenge, revealing that schools still have to develop effective strategies to balance social and learning opportunities among students. © 2012 Elsevier Ltd. All rights reserved.

Xiao Y.,Zhejiang University
International Journal of Biochemistry and Cell Biology | Year: 2011

Enhancer of zeste homolog 2 (EZH2) is a subunit of the Polycomb-Repressive Complex 2 (PRC2), which catalyses the trimethylation of histone H3 on Lys 27 (H3K27) and involves in genes repression. EZH2 is amplified and overexpressed in a variety of cancers, including prostate and breast cancer. Overexpression of EZH2 has been associated with the invasion and progression of malignant cancers, especially with the progression of prostate cancer. Here, we review the structure and biological function of EZH2, especially focused on its activities in the tumorigenesis. © 2011 Elsevier Ltd. All rights reserved.

Zhu J.,Zhejiang University
Advances in Information Sciences and Service Sciences | Year: 2012

The problem of evaluating security of Wireless Sensor Network (WSN) with intuitionisitc fuzzy information is the multiple attribute decision making (MADM). In this paper, we investigate the multiple attribute decision making(MADM) problems for evaluating the security of wireless sensor networks with intuitionistic fuzzy information. We utilize the intuitionistic fuzzy hybrid geometric (IFHG) operator to aggregate the intuitionistic fuzzy numbers corresponding to each alternative and derive the overall value of the alternatives, then rank the alternatives and select the most desirable one(s) according to the score function and accuracy function. Finally an illustrative example has been given to show the developed approach.

Gan Y.,Zhejiang University | Chen J.K.,University of Missouri
Computer Physics Communications | Year: 2012

A numerical method coupling the molecular dynamics and the two-step energy transfer model is presented for simulating ultrafast responses of semiconductors irradiated by ultrashort-pulsed lasers. In this method, an additional damping force characterizing the carrier-lattice heat exchange is added to the equations of motion of atoms in the molecular dynamics. The explicit finite difference algorithms are applied for obtaining the laser energy distribution and the carrier density evolution, whereas a semi-implicit finite difference scheme is developed as for the carrier temperature field. Examples of a thin silicon film subjected to femtosecond laser heating are utilized to validate and demonstrate this hybrid method. Results show that the proposed method is able to effectively describe not only the thermal transport but also the thermal stress wave in the ultrafast laser-semiconductor interactions. © 2011 Elsevier B.V. All rights reserved.

The fresh water clam Corbicula fluminea is currently one of the most economically important aquatic species in China because of its nutritional value and pharmacological activity. In order to explore the potential of C. fluminea as a natural resource of bioactive compounds, a papain-released polysaccharide designated CFPS-2 was isolated. Chemical composition analysis indicated that CFPS-2 contained glucosamine, glucose, galactose, fucose, protein and sulfate groups, with an average molecular weight of about 22 kDa. Furthermore, the antioxidant and antitumor activities, in vitro, of the polysaccharide fractions (crude CFPS and purified CFPS-2) were evaluated. CFPS-2, which exhibited strong antioxidant activities in a dose dependent manner also showed significant inhibitory effects on growth of human gastric cancer cells (SGC7901) and human ovarian carcinoma cells (SKOV3 and A2780). The present results suggest that CFPS-2 could be a potential candidate for the development of novel functional food ingredient.

Yu T.,Washington University in St. Louis | Kim D.Y.,Washington University in St. Louis | Kim D.Y.,Korea Advanced Institute of Science and Technology | Zhang H.,Washington University in St. Louis | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Many facets: A simple synthetic route, which is based on reduction in aqueous solution, results in Pt concave nanocubes (see picture) enclosed by high-index facets such as {510}, {720}, and {830}. The nanocrystals exhibit electrocatalytic activity (per unit surface area) that is 3.5 times higher than the commercial Pt/C catalyst in the oxygen reduction reaction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

To evaluate the effect and results of short and medium periods of follow-up of percutaneous balloon pulmonary valvuloplasty for critical pulmonary stenosis of neonates and infants under 6 months of age. Between January 2002 and December 2008, 34 consecutive patients aged from 13 to 175 days with critical pulmonary valvular stenosis underwent percutaneous balloon valvuloplasty. Patients records, catheterization data, angiograms and echocardiograms were reviewed. Patients were followed up for 6 months to 4 years (mean 25.5 months) by means of clinical examination and Doppler echocardiography. The pulmonary valvuloplasty was accomplished in 32 (94%) of 34 attempts. Immediately after dilation, right ventricular systolic pressure (RVSP) decreased from (96 ± 28) mm Hg (1 mm Hg = 0.133 kPa) (49 ± 20) mm Hg (P < 0.01), the transvalvular peak to peak systolic gradient (ΔP) decreased from (89 ± 25) mm Hg to (25 ± 12) mm Hg (P < 0.01), and the right ventricular/aortic systolic pressure ratio decreased from 1.2 ± 0.5 to 0.7 ± 0.3 (P < 0.01). One patient died because of cardiac tamponade following rupture of the pulmonary valve annulus, 2 patients developed pericardial effusion, 3 patients had infundibular spasm, 3 patients had a pre-dilation by small balloon and 1 patient had weakened femoral artery pollex. After a follow up period of 6 months to 4 years 3 of 31 patients lost to follow-up. Repeat valvuloplasty was performed in 5 patients (3 neonates), no patient required surgery, and the other 23 patients did not undergo further intervention, a mean peak systolic Doppler gradient of (20 ± 13) mm Hg was found and no significant pulmonary regurgitation was seen. Percutaneous balloon pulmonary valvuloplasty was effective and safe for the treatment of critical pulmonary stenosis of neonates and infants under 6 months of age with good short and medium term results.

Zhao C.,Zhejiang University
IEEE Transactions on Automation Science and Engineering | Year: 2014

Competition and demand for consistent and high-quality product have spurred the development of quality prediction methods for industrial manufacturing processes. Multiplicity of phases is, in general, common nature of many batch manufacturing processes. Considering that different phases may have different effects on qualities, one of the key issues is how to partition the whole batch process into multiple phases. In the present work, an automatic quality-relevant step-wise sequential phase partition (QSSPP) algorithm is developed for phase-based regression modeling and quality prediction. It considers the time sequence of operation phases and can capture the time-varying quality prediction relationships. Using this algorithm, phases are separated in order from quality-relevant perspective, revealing different quality prediction relationships. The phase-based regression system is set up for online quality prediction and the online prediction results are quantitatively evaluated for each phase. The feasibility and performance of the proposed algorithm are illustrated by an important manufacturing process, injection molding. © 2013 IEEE.

Based on the electro-mechanical coupling theory and the laminate elasticity theory, an electro-elastic solution is obtained for the fiber-reinforced cylindrical composites with integrated piezoelectric actuators when subjected to mechanical and electrical loadings. The hybrid composite is composed of three parts: internal piezoelectric actuator, fiber-reinforced laminated interlayer, and external piezoelectric actuator. The general solution in each piezoelectric smart layer is obtained by introducing three undetermined constants, and the general solutions in the fiber-reinforced laminated interlayer are obtained by means of the state-space method. The mechanical behaviors of the hybrid fiber-reinforced cylindrical composites are investigated. The illustrative examples show that the fiber's angle, the stacking sequence as well as the applied electric loading strongly affect the physical fields in the fiber-reinforced multilayered cylindrical composites. © 2013 Springer-Verlag Berlin Heidelberg.

Cheng W.P.,Zhejiang University | Jia Y.,University of Mississippi
Advances in Water Resources | Year: 2010

A backward location probability density function (BL-PDF) method capable of identifying location of point sources in surface waters is presented in this paper. The relation of forward location probability density function (FL-PDF) and backward location probability density, based on adjoint analysis, is validated using depth-averaged free-surface flow and mass transport models and several surface water test cases. The solutions of the backward location PDF transport equation agreed well to the forward location PDF computed using the pollutant concentration at the monitoring points. Using this relation and the distribution of the concentration detected at the monitoring points, an effective point source identification method is established. The numerical error of the backward location PDF simulation is found to be sensitive to the irregularity of the computational meshes, diffusivity, and velocity gradients. The performance of identification method is evaluated regarding the random error and number of observed values. In addition to hypothetical cases, a real case was studied to identify the source location where a dye tracer was instantaneously injected into a stream. The study indicated the proposed source identification method is effective, robust, and quite efficient in surface waters; the number of advection-diffusion equations needed to solve is equal to the number of observations. © 2010 Elsevier Ltd.

OBJECTIVE:: Sterile alpha motif and histidine/aspartic acid domain-containing protein 1 (SAMHD1), a newly discovered human immunodeficiency virus (HIV)-1 host restriction factor, has been found to be induced by interferons (IFNs) and to be regulated by miR-181a. However, the mechanism of IFNs induced SAMHD1 expression is unclear. DESIGN:: We hypothesized that IFNs induce SAMHD1 expression through JAK-STAT signaling pathways, which is mediated by miR-181a. METHODS:: We examined the effect of IFN-α and IFN-γ on SAMHD1 mRNA and protein expression, as well as the levels of phosphorylated SAMHD1 and miR-181a in astrocytes and microglia. To determine whether IFN-induced SAMHD1 expression was mediated by miR-181a, we overexpressed or inhibited miR-181a in these cells and exposed them to IFNs. We also detected the effect of SAMHD1 and miR-181a on HIV-1 infection in astrocytes and microglia. RESULTS:: Both IFN-α and IFN-γ increased SAMHD1 mRNA and protein expression, and reduced miR-181a levels, particularly in microglia. Phosphorylated SAMHD1was not induced by IFNs. Overexpression of miR-181a counteracted induction of SAMHD1 expression by IFNs, and inhibition of miR-181a mimicked IFNs treatment. Inhibition of JAK-STAT signaling pathways resulted in increased miR-181a levels and decreased SAMHD1 mRNA expression. Knock-down of SAMHD1 or overexpression of miR-181a enhanced HIV-1 infection, while inhibition of miR-181a reduced HIV-1 infection. However, inhibition of HIV-1 infection induced by IFN-α was not significantly affected by miR-181a and SAMHD1. CONCLUSIONS:: MiR-181a is an important mediator for IFNs induced SAMHD1 expression in astrocytes and microglia, but not for inhibition of HIV-1 infection induced by IFN-α. Copyright © 2016 Wolters Kluwer Health, Inc.

This article provides a historical account of Chinese public policy on fisheries subsidies, and a discussion of problems and limitations resulting from the World Trade Organization (WTO) Doha Round fisheries subsidies negotiation. By analyzing subsidization trends and applying a proportional assessment of subsidized areas, the article tracks the evolvement of Chinese fishery policy objective and priorities. Chinese fishery is not historically significantly subsidized in light of its relatively market-oriented structure and a sustained momentum in reducing marine capture capacity. However, due to the commitment to encouraging qualitative growth and to satisfying a rising domestic demand for fish, the government seeks for adequate policy space to employ fuel, distant water fisheries, infrastructure and various 'green light' subsidies. Whether or not such a claim can be accepted as a developmental right not an exception remains to be answered by the revision of current negotiation draft. © 2015 Elsevier Ltd.

Zhang L.,Hangzhou Dianzi University | Wu J.,Zhejiang University
Journal of Physics A: Mathematical and Theoretical | Year: 2014

In this paper, a lower bound of quantum conditional mutual information is obtained by employing the Peierls-Bogoliubov inequality and the Golden-Thompson inequality. Comparison with the bounds obtained by other researchers indicates that our result is independent of any measurements. It may give some new insights into squashed entanglement and perturbations of Markov chain states. © 2014 IOP Publishing Ltd.

Pittelkow C.M.,University of California at Davis | Pittelkow C.M.,Urbana University | Liang X.,Zhejiang University | Linquist B.A.,University of California at Davis | And 8 more authors.
Nature | Year: 2015

One of the primary challenges of our time is to feed a growing and more demandingworld population with reduced external inputs and minimal environmental impacts, allundermore variable and extreme climate conditions in the future1-4. Conservation agriculture represents a set of three crop management principles that has received strong international support to help address this challenge5,6, with recent conservation agriculture efforts focusing on smallholder farming systems in sub-Saharan Africa and South Asia7.However, conservationagriculture is highly debated, with respect to both its effects on crop yields8-10 andits applicability in different farming contexts7,11-13. Here weconduct a globalmeta-analysis using 5,463 paired yield observations from610 studies to compare no-till, the original and central concept of conservation agriculture, with conventional tillage practices across 48 crops and 63 countries. Overall, our results show that no-till reduces yields, yet this response is variable and under certain conditions no-till can produce equivalent or greater yields than conventional tillage. Importantly,whenno-till is combined with the other two conservation agriculture principles of residue retention and crop rotation, its negative impacts are minimized. Moreover, no-till in combination with the other two principles significantly increases rainfed cropproductivity indry climates, suggesting that itmaybecome animportant climate-change adaptation strategy for ever-drier regions of the world. However, any expansion of conservation agriculture should be done with caution in these areas, as implementation of the other two principles is often challenging in resource-poor and vulnerable smallholder farming systems, thereby increasing the likelihood of yield losses rather than gains. Although farming systems are multifunctional, and environmental and socio-economic factors need to be considered14-16, our analysis indicates that the potential contribution of no-till to the sustainable intensification of agriculture is more limited than often assumed. © 2015 Macmillan Publishers Limited.

Rao J.,Zhejiang University
Journal of High Energy Physics | Year: 2015

Abstract: Inspired by the new soft theorem in gravity by Cachazo and Strominger, the soft theorem for color-ordered Yang-Mills amplitudes has also been identified by Casali. In this note, the same content of N = 4 SYM using the Grassmannian formulation is studied. Explicitly, in the holomorphic soft limit, we reduce the n-particle amplitude in terms of Grassmannian contour integrations into the deformed (n − 1)-particle amplitude by localizing k variables relevant to the n-th particle. Afterwards, the leading soft factor and sub-leading soft operator naturally emerge. © 2015, The Author(s).

Wu Y.,China National Center for Food Safety Risk Assessment | Zhang Y.,Zhejiang University
Food and Chemical Toxicology | Year: 2013

This review summarizes the most recent scientific literature and regulations regarding analytical chemistry, toxicology, epidemiology, exposure, and risk assessment of melamine in infant formula. For analyses, enzyme-linked immunosorbent assay, high-performance liquid chromatography, capillary electrophoresis, gas chromatography coupled with mass spectrometry and liquid chromatography coupled with tandem mass spectrometry have commonly been used. Organization of proficiency test programs provided good evidence to facilitate granting laboratories accreditation and to ascertain the measurement reliability of melamine methods. Metabolic studies demonstrated that melamine is predominantly restricted to blood or extracellular fluid and is not extensively distributed to organs and tissues. Studies of human renal histopathology and clinical diagnoses indicated that melamine-related obstructive nephropathy derives from melamine precipitation in the lower urinary tract, with stones that are thought to be melamine-uric acid complexes. Epidemiologic studies showed that the occurrence of melamine-related urolithiasis is related to both the concentration of melamine in ingested milk products and the duration of ingestion. Long-term follow-up cohort studies should be continued to further investigate the epidemic and chronic hazard of melamine-induced nephrotoxicity. The World Health Organization set a tolerable daily intake of 0.2. mg/kg. bw/day to be applied to " the whole population including infants" Other authorities and research institutes have set/proposed lower values. © 2013 Elsevier Ltd.

Li D.,Zhejiang University
Journal of Agricultural and Food Chemistry | Year: 2011

This review summarizes the effect of a habitual vegetarian diet on clinical complications in relation to chemistry and biochemistry. Omnivores have a significantly higher cluster of cardiovascular risk factors compared with vegetarians, including increased body mass index, waist to hip ratio, blood pressure, plasma total cholesterol (TC), triacylglycerol and LDL-C levels, serum lipoprotein(a) concentration, plasma factor VII activity, ratios of TC/HDL-C, LDL-C/HDL-C and TAG/HDL-C, and serum ferritin levels. Compared with omnivores, vegetarians, especially vegans, have lower serum vitamin B12 concentration and n-3 polyunsaturated fatty acid (PUFA) levels in the tissue membrane phospholipids, which are associated with increased collagen and ADP stimulated ex vivo whole blood platelet aggregation, plasma 11-dehydrothromboxane B 2, and homocysteine levels and decreased plasma HDL-C. This may be associated with an increased thrombotic and atherosclerotic risk. It is suggested that vegetarians, especially vegans, should increase their dietary n-3 PUFA and vitamin B 12 intakes. © 2011 American Chemical Society.

Niu W.,University of Texas Southwestern Medical Center | Zang T.,University of Texas Southwestern Medical Center | Zou Y.,University of Texas Southwestern Medical Center | Fang S.,University of Texas Southwestern Medical Center | And 4 more authors.
Nature Cell Biology | Year: 2013

Adult differentiated cells can be reprogrammed into pluripotent stem cells or lineage-restricted proliferating precursors in culture; however, this has not been demonstrated in vivo. Here, we show that the single transcription factor SOX2 is sufficient to reprogram resident astrocytes into proliferative neuroblasts in the adult mouse brain. These induced adult neuroblasts (iANBs) persist for months and can be generated even in aged brains. When supplied with BDNF and noggin or when the mice are treated with a histone deacetylase inhibitor, iANBs develop into electrophysiologically mature neurons, which functionally integrate into the local neural network. Our results demonstrate that adult astrocytes exhibit remarkable plasticity in vivo, a feature that might have important implications in regeneration of the central nervous system using endogenous patient-specific glial cells. © 2013 Macmillan Publishers Limited. All rights reserved.

Zhu Y.,Beijing University of Chemical Technology | Tang G.-P.,Zhejiang University | Xu F.-J.,Beijing University of Chemical Technology