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Lanzhou, China

Lanzhou University is a major research university in Lanzhou, Gansu Province, China. Founded in 1909, it is one of the key universities under China's Ministry of Education . It provides programs for undergraduate, graduate students on four campuses—three in Lanzhou city centre and one in Yuzhong County, about 30 miles away from the main campus. Total enrolment is approximately 20,000. Undergraduate students study at the Yuzhong campus. There are 6 National Bases for the Training of Researching and Teaching personnel for Fundamental Disciplines. The University operates an additional 35 institutes along with 1 national key Laboratory of the Applied Organic and 3 key laboratories of Arid and Grassland Ecology, West China Environment, Magnetism and Magnetic Materials of the Ministry of Education, a key laboratory of Grassland Agro-ecosystem of the Ministry of Agriculture. Lanzhou University was one of the first universities entitled to enroll Bachelor Master’s and Doctoral degree candidates in 1981. Lanzhou University is one of the top ten universities in contributions to academic publications in international journals frequently cited by ongoing research from around the world. Wikipedia.

Wang J.-Z.,Dongbei University of Finance and Economics | Wang Y.,Lanzhou University | Jiang P.,Dongbei University of Finance and Economics
Applied Energy | Year: 2015

Given the current increasingly serious energy crisis, the development and utilization of new energy resources are attracting increasing attention, and wind power is widely used among these renewable energy resources. However, the randomness of wind power can cause a series of problems in the power system. Furthermore, the integration of large-scale wind farms into the whole power grid can place a great burden on stability and security. Accurate wind speed forecasting would reduce the randomness of wind power, which could effectively alleviate the adverse effects on the power system. In this paper, a hybrid wind speed forecasting model is proposed with the hope of achieving better forecasting performance. Wavelet Packet Transform (WPT) was employed to decompose the wind speed series into several series with different frequencies. A Least Square Support Vector Machine (LSSVM), the parameters of which were tuned by a particle swarm optimization based on simulated annealing (PSOSA), was built to model those series. The optimal input form of the model was determined by Phase Space Reconstruction (PSR). To verify the effectiveness of the proposed model, the daily average wind speed series from four wind farms in Gansu Province, Northwest China, were used as a case study. The results of the simulation and Grey Relational Analysis indicate that the proposed model outperforms the comparison models, and the null hypothesis of the predicted series having the same mean of the real series was accepted. © 2015 Elsevier Ltd.

Qin H.-H.,Lanzhou University | Cakoni F.,University of Delaware
Inverse Problems | Year: 2011

In this paper, we consider the inverse scattering problem of recovering the shape of a perfectly conducting cavity from one source and several measurements placed on a curve inside the cavity. Under restrictive assumptions on the size of the cavity, a uniqueness theorem for finitely many excitations is given. Based on a system of nonlinear and ill-posed integral equations for the unknown boundary, we apply a regularized Newton iterative approach to find the boundary. We present the mathematical foundation of the method and give several numerical examples to show the viability of the method. © 2011 IOP Publishing Ltd.

Lin R.,Lanzhou University
International Journal of Computer Mathematics | Year: 2015

Augmented k-ary n-cube (Formula presented.) is proposed as a new interconnection network model by Xiang and Steward [Augmented k-ary n-cubes, Inform. Sci. 181(1) (2011), pp. 239–256]. For a connected graph G, an edge-cut (vertex-cut) S is called a restricted edge-cut (restricted vertex-cut) if G–S contains no isolated vertices. The restricted edge-connectivity (restricted connectivity) of G, denoted by (Formula presented.) ((Formula presented.)), is the minimum cardinality over all restricted edge-cuts (vertex-cuts) of G. In this paper, we completely determine the restricted (edge-)connectivity of (Formula presented.). Precisely, (Formula presented.) for (Formula presented.); (Formula presented.) for (Formula presented.), (Formula presented.) for (Formula presented.), (Formula presented.) for (Formula presented.) and (Formula presented.), but (Formula presented.) does not have restricted vertex-cut. © 2015 Taylor & Francis

Wang G.,Arizona State University | Huang L.,Arizona State University | Huang L.,Lanzhou University | Lai Y.-C.,Arizona State University | And 2 more authors.
Physical Review Letters | Year: 2014

To search for and exploit quantum manifestations of classical nonlinear dynamics is one of the most fundamental problems in physics. Using optomechanical systems as a paradigm, we address this problem from the perspective of quantum entanglement. We uncover strong fingerprints in the quantum entanglement of two common types of classical nonlinear dynamical behaviors: periodic oscillations and quasiperiodic motion. There is a transition from the former to the latter as an experimentally adjustable parameter is changed through a critical value. Accompanying this process, except for a small region about the critical value, the degree of quantum entanglement shows a trend of continuous increase. The time evolution of the entanglement measure, e.g., logarithmic negativity, exhibits a strong dependence on the nature of classical nonlinear dynamics, constituting its signature. © 2014 American Physical Society.

Wen J.,Lanzhou University
Inverse Problems in Science and Engineering | Year: 2011

In this article, we use the method of fundamental solutions to reconstruct the heat source and part of the initial temperature simultaneously in one-dimensional heat conduction problem. This problem is ill-posed, thus a Tikhonov regularization method with generalized cross-validation criterion is applied to obtain a stable numerical solution. Numerical experiments for several examples show that the proposed method is reasonable and feasible. © 2011 Taylor & Francis.

Su X.,Changan University | Li J.,Lanzhou University
Journal of Materials Science and Technology | Year: 2011

Single-crystal alpha alumina (α-Al 2O 3) platelets were synthesized by calcining a powder mixture of bayerite (α-Al(OH) 3) and potassium sulfate (K 2SO 4) at 900°C. The crystalline phase evolutions and morphologies of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The synthesized samples mainly consisted of single-crystal α-Al 2O 3 platelets with a diameter of 0.5-1.5 μm and a thickness of 50-150 nm. Moreover, with 3, 5, and 8 wt% (referred to the obtained alumina) α-Al 2O 3 seeds adding into the powder mixture of bayerite and potassium sulfate, the average diameter of α-Al 2O 3 platelets can be reduced to 450, 240, and 220 nm, respectively. It is found that the sequence of the phase transformation is the bayerite (α-Al(OH) 3) → boehmite (γ-AlOOH) → γ-Al 2O 3 → α-Al 2O 3. Further analysis indicated that K 2SO 4 can promote the phase transformation from γ-Al 2O 3 to α-Al 2O 3 and the formation of single-crystal α-Al 2O 3 platelets might be attributed to the liquid phase K 3Al(SO 4) 3. © 2011 The Chinese Society for Metals.

Lin G.,Lanzhou University
Nonlinear Analysis: Real World Applications | Year: 2011

This paper is concerned with the long time behavior of the delayed Fisher equation without quasimonotonicity. It is shown that, when the instantaneous self-limitation effect dominates the corresponding delayed effect, the spreading speed is the same as that of the classical Fisher equation. © 2011 Elsevier Ltd. All rights reserved.

Wang Z.-Y.,King Abdullah University of Science and Technology | Wang Z.-Y.,Lanzhou University | Xiong L.,King Abdullah University of Science and Technology | Li W.,University of California at Riverside | And 3 more authors.
Plant Cell | Year: 2011

Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

Yang F.L.,Lanzhou University | Ling L.,Hong Kong Baptist University
Engineering Analysis with Boundary Elements | Year: 2011

Over the last decade, there has been a considerable amount of new numerical methods being developed for solving the Cauchy problems of elliptic operators. In this paper, with some new classes of numerical experiments, we re-verify the conclusions in the review article [Wei T, Hon YC, Ling L. Method of fundamental solutions with regularization techniques for Cauchy problems of elliptic operators. Eng Anal Bound Elem 2007;31(4):37385.] concerning the effectiveness of solving Cauchy problems with the method of fundamental solutions. © 2011 Elsevier Ltd.

Zhao P.,Lanzhou University
Probability in the Engineering and Informational Sciences | Year: 2011

In this article, we study ordering properties of lifetimes of parallel systems with two independent heterogeneous gamma components in terms of the likelihood ratio order and the hazard rate order. Let X1 and X 2 be two independent gamma random variables with Xi having shape parameter r > 0 and scale parameter λi, i=1, 2, and let X*1 and X*2 be another set of independent gamma random variables with X*i having shape parameter r and scale parameter λ*i, i=1, 2. Denote by X2:2 and X*2:2 the corresponding maximum order statistics, respectively. It is proved that, among others, if (λ1, λ2) weakly majorize (λ*1, λ*2), then X2:2 is stochastically greater than X*2:2 in the sense of likelihood ratio order. We also establish, among others, that if 0

Wang G.,Michigan Technological University | Si M.,Lanzhou University | Kumar A.,Michigan Technological University | Pandey R.,Michigan Technological University
Applied Physics Letters | Year: 2014

6,6,12-graphyne, one of the two-dimensional carbon allotropes with the rectangular lattice structure, has two kinds of non-equivalent anisotropic Dirac cones in the first Brillouin zone. We show that Dirac cones can be tuned independently by the uniaxial compressive strain applied to graphyne, which induces n-type and p-type self-doping effect, by shifting the energy of the Dirac cones in the opposite directions. On the other hand, application of the tensile strain results into a transition from gapless to finite gap system for the monolayer. For the AB-stacked bilayer, the results predict tunability of Dirac-cones by in-plane strains as well as the strain applied perpendicular to the plane. The group velocities of the Dirac cones show enhancement in the resistance anisotropy for bilayer relative to the case of monolayer. Such tunable and direction-dependent electronic properties predicted for 6,6,12-graphyne make it to be competitive for the next-generation electronic devices at nanoscale. © 2014 AIP Publishing LLC.

Mischke S.,Free University of Berlin | Zhang C.,Lanzhou University
Global and Planetary Change | Year: 2010

A lake sediment core from the eastern Tibetan Plateau was investigated by multi-proxy geochemical, sedimentological and magnetic analyses and its age determined using 14C AMS dating in an approach to use short-lived climate periods for a spatial assessment of the Holocene climate history on the Tibetan Plateau. Six cold events were identified from the Lake Ximencuo record which occurred between 10.3-10.0, 7.9-7.4, 5.9-5.5, 4.2-2.8, 1.7-1.3 and 0.6-0.1cal ka BP. A comparison with previously published Holocene records from lake and peat sections, ice cores and glacial remains of the Tibetan Plateau revealed that the cold event starting around 4.2cal ka BP had the most significant and widespread impact on almost all of the examined sites. This cold event lasted about a millennium in the western and central part of the Tibetan Plateau and possibly several hundred years longer at some sites in its eastern realm. The cold event inferred between 7.9 and 7.4cal ka BP from Lake Ximencuo was recorded at a number of sites on the eastern Tibetan Plateau too and probably corresponds to a cold event identified around 8.2cal ka BP at the sites on the western and central Tibetan Plateau. The coincidence with the 8.2ka event of the North Atlantic region implies that the latter exerted a significant environmental impact on the Tibetan Plateau too. The cold spell between 10.3 and 10.0cal ka BP was recorded at some marginal sites of the Tibetan Plateau but had apparently a less significant environmental impact. The more irregular pattern of cold events between about 7cal ka BP and the onset of the cold event after 4.2cal ka BP might be related to the catchment-specific response of the lake sediment and peat accumulation to the termination of the Holocene 'climatic optimum' on the Tibetan Plateau. The final two cold events between 1.7 and 1.3cal ka BP and in the last several hundred years representing the Little Ice Age are more widely seen on the Tibetan Plateau although they did not reach the significance of the cold event at 4.2cal ka BP. However, the three cold periods since 4.2cal ka BP are apparently coeval with the decline and establishment of Chinese Dynasties implying a remarkable impact on the social systems in eastern China. The consistent inference of cold events around 8.2cal ka BP or a few hundred years later and starting at 4.2cal ka BP is evidence for a temporary trans-regional climatic response on the Tibetan Plateau in the Holocene regardless of the catchment-specific response of complex natural systems. © 2010 Elsevier B.V.

To investigate the influence of bone marrow stromal stem cell (BMSCs) transplantation on healing of fractures combined with central nerve injuries in rats. Forty-eight healthy adult SD male rats were randomly divided into the following three groups (16 rats in each group): group A, simple (left) tibial fracture; group B, tibial fracture combined with T10 spinal cord transection (SCT); group C, tibial fracture combined with T10 SCT and BMSCs transplantation. The tibial fractures were stabilized with modular intramedullary nails and all operated hind limbs were further immobilized in plaster casts to prevent unequal load bearing. BMSCs were labeled with bromodeoxyuridine and implanted into the fractures of C group rats 2 days after creation of the model. The animals in B and C groups were evaluated by postoperative Tarlov scores. The fractured tibiae were evaluated separately radiographically (X-ray and CT) and immunohistochemically 1, 2, 3 and 4 weeks after injury to assess fracture healing. In addition, the wet weights of the left tibias were measured. All Tarlov score of the B and C group animals reached the requirements of the experiment. One, 2 and 3 weeks after surgery, the tibial callus widths in B and C group animals were significantly greater than those of group A rats (P < 0.05). At 4 weeks the tibial callus width in group C animals had decreased, but still differed significantly from that in group A rats (P < 0.05). One, 2, 3 and 4 weeks after surgery, the wet weights of B and C group tibias were significantly greater than those of group A (P < 0.05). Hematoxylin-eosin-stained sections showed bony union and increased bone trabecula in B and C groups and areas with particles positive for alkaline phosphatase staining were more abundant in groups B and C, especially in group C. Neural regulation plays an important role in fracture healing. Treatment with BMSCs has a positive effect on defective callus in rats that have been subjected to SCT. © 2013 Chinese Orthopaedic Association and Wiley Publishing Asia Pty Ltd.

Li L.,Lanzhou University
Cochrane database of systematic reviews (Online) | Year: 2010

A monoclonal CCR5 antibody, PRO 140 (a humanised form of the PA14 antibody), inhibits CCR5-tropic (R5) HIV-1. This may be an effective new treatment for HIV-infected patients, with the potential to address the limitations of currently available therapies. We aimed to assess the efficacy and safety of PRO 140 for HIV-1-infected patients in randomised controlled trials (RCTs). Databases including Cochrane's CENTRAL, PubMed, EMBASE and ISI Web of Knowledge, online trials registries and other sources were searched. The reference lists of related literature and presentations from major HIV/AIDS conferences were also screened. RCTs and quasi-RCTs comparing PRO 140 with placebo or other antiretroviral drugs, or different doses for individuals infected with HIV. Two reviewers (L Li and TT Sun) independently screened all retrieved citations and selected relevant citations. Data were extracted independently by two authors (P Zhang and WQ Jia). Any disagreements when selecting studies and extracting data were adjudicated the review mentor (KH Yang). RevMan software was used for statistical analysis based an intention-to-treat analysis. Heterogeneity was examined using the I(2) statistic. I(2) estimates greater than 50% were regarded as moderate or high levels. According to the level of heterogeneity, either fixed or random effects models were used. If significant heterogeneity existed and the reasons could not be found, we reported the results qualitatively. We included 2 trials comparing PRO 140 with placebo in adult patients with HIV infection. Our review indicates that PRO 140 may offer significant dose-dependent HIV-1 RNA suppression with tolerable side effects. PRO 140 2mg/Kg, 5 mg/Kg, 162mg weekly, 324 mg biweekly, 324 mg weekly showed statistically significant differences in the changes of HIV RNA level. Both HIV-1 RNA levels of PRO 140 2mg/Kg, 5mg/Kg on day 10 and PRO 140 162mg weekly, 324 mg biweekly, 324 mg weekly on day 22 were significantly reduced. PRO 140 0.5mg/Kg, 2mg/Kg, 5mg/Kg, 162 mg weekly; 324 mg biweekly; 324 mg weekly demonstrated greater antiviral response. Only PRO 140 324 mg weekly showed more patients with ≦400 copies/mL HIV-1 RNA. Only PRO 140 5 mg/Kg showed greater change in CD4(+) cell count on day 8. Headache, lymphadenopathy, diarrhoea, fatigue, and hypertension were reported to be the most frequent adverse events. Limited evidence from two small trials suggests that PRO 140 might demonstrate potent, dose-dependent, highly significant antiviral activity. The evidence is insufficient, so recommendations cannot yet be made. Larger, longer-term, double-blind RCTs are required to provide conclusive evidence.

Yang Y.,Lanzhou University | Wang Y.,Harbin Institute of Technology | Fu F.,City University London
Thin-Walled Structures | Year: 2014

Eight stiffened square concrete-filled steel tubular (CFST) stub columns with slender sections of encasing steel and two non-stiffened counterparts were tested subjected to axial compressive load. Four types of reinforcement stiffeners and steel tensile strips were introduced to postpone local buckling of steel tubes, in which the tensile strip was first used as stiffener in CFSTs. The stiffening mechanism, failure modes of concrete and steel tubes, strength and ductility of stiffened square CFSTs were also studied during the experimental research. A numerical modeling program was developed and verified against the experimental data. The program incorporates the effect of the stiffeners on postponing local buckling of the tube and the tube confinement on concrete core. Extensive parametric analysis was also conducted to examine the influencing parameters on mechanical properties of stiffened square CFSTs. © 2014 Elsevier Ltd.

A systematic review and meta-analysis were designed to evaluate the efficacy and safety of probiotics for prevention of chemoradiotherapy-induced diarrhea in people with abdominal and pelvic cancer. We searched the Cochrane Library, PubMed, EMBASE and Web of Science up to November 2015. We also hand searched the citation lists of included studies and previously identified systematic reviews to identify further relevant trials. Odds ratio (OR) was used to compare efficacy, and the pooled OR was estimated using a random effects model; heterogeneity was assessed with Cochran’s Q and the Higgins’ I2-test. Two reviewers assessed trial quality and extracted data independently. Analysis and bias for each included study were performed using Review Manager 5.2. Nine randomized and placebo-controlled studies (N=1265 participants) were included for assessing efficacy, of which seven were about radiotherapy and two about chemotherapy. Probiotic groups were compared with control groups with respect to the the incidence of diarrhea, OR=0.47 (95% confidence interval 0.28–0.76; P=0.002). Eleven studies, including 1612 people (873 consuming probiotics and 739 not consuming probiotics), were used for the analysis of safety of probiotics. Of the 11 studies, seven studies had no adverse events (AEs) caused by probiotics, whereas four studies reported varying degrees of AEs in their treatment. Probiotics may have a beneficial effect in prevention of chemoradiotherapy-induced diarrhea generally, especially for Grade⩾2 diarrhea. Probiotics may rarely cause AEs.European Journal of Clinical Nutrition advance online publication, 15 June 2016; doi:10.1038/ejcn.2016.102. © 2016 Macmillan Publishers Limited

Duan H.,Massachusetts Institute of Technology | Duan H.,Lanzhou University | Berggren K.K.,Massachusetts Institute of Technology
Nano Letters | Year: 2010

We demonstrated a new nanoassembly strategy based on capillary force-induced cohesion of high-aspect ratio nanostructures made by electron-beam lithography. Using this strategy, ordered complex pattern were fabricated from individual nanostructures at the 10 nm length scale. This method enables the formation of complex designed networks from a sparse array of nanostructures, suggesting a number of potential applications in fabrication of nanodevices, nanopatterning, and fluid-flow investigations. © 2010 American Chemical Society.

Yin J.,University of Birmingham | Harrison R.M.,University of Birmingham | Chen Q.,Lanzhou University | Rutter A.,University of Wisconsin - Madison | Schauer J.J.,University of Wisconsin - Madison
Atmospheric Environment | Year: 2010

Airborne fine particulate matter (PM2.5) has been collected at two sites in the West Midlands conurbation, UK, representing urban background and rural locations. Chemical analyses have been carried out for major anions, trace metals, total OC and EC, and for individual organic marker species including n-alkanes, hopanes, PAHs, organic acids and sterols. Source apportionment has been conducted using both a pragmatic mass closure model and the US EPA chemical mass balance (CMB) model. The pragmatic mass closure model is well able to account for the measured PM2.5 mass in terms of chemical/source components, and the chemical mass balance model has been used to apportion the carbonaceous component of the aerosol. The dominant components of PM2.5 at both sites are secondary inorganic (sulphate and nitrate) and carbonaceous particles. The CMB model shows the latter to arise mainly from road traffic sources, with smaller contributions from vegetative detritus, wood smoke, natural gas, coal, and dust/soil. The CMB model also identifies an important component of the organic aerosol not associated with these primary sources, which correlates very strongly with secondary organic aerosol estimated from the OC/EC ratio. The split between different automotive source types does not relate well to UK emission inventories, and may indicate that CMB source profiles from North American studies and different carbon analysis protocols may lead to erroneous conclusions. © 2009 Elsevier Ltd. All rights reserved.

Gao X.Q.,Lanzhou University
Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] | Year: 2012

To investigate the epidemiological features and types of human adenoviruses (ADV) in children with acute respiratory tract infection in Nanjing area, China. Nasopharyngeal aspirates and nasopharyngeal swabs were collected from 644 outpatients or hospitalized pediatric patients with ARTI at the Children Hospital of Nanjing, Jiangsu Province, China, between August 2010 and July 2011. Adenoviruses were identified and typed from the collected clinical specimens by nested-PCR based on the partial region of the hexon gene. Other 12 respiratory viruses including human bocavirus (HBoV), respiratory syncytial virus (RSV), human rhinovirus (HRV), parainfluenza viruses 1-4 (PIV1-4), influenza virus A/B (IFVA/B), human metapneumovirus (HMPV), human coronavirus NL63 and HKU1 (HCoV-HKU1 and HCoV-NL63) were also identified by PCR method. All PCR positive products were sequenced and phylogenetic analysis was conducted. It was showed that adenoviruses were detected in 171 patients out of 644 (26. 55%) children, 120 (70.18%, 120/171) for ADV3, 16 (9.36%,16/171) for ADV7, 12 (7.02%, 12/171) for ADV1, 10 (5.85%, 10/171) for ADV2, 6 (3.51%, 6/171) for ADV5, 3 (1.75%, 3/171) for ADV6, 3 (1.75%, 3/171) for ADV57, and 1 (0.58%,1/171) for ADV41. ADV infection could occur in any season. There was a higher possibility of ADV infection from April to July in 2011. Most cases (96.49%) were younger than 7 years old. A total of 99 of the 171 ADV-positive children (57.89%) were co-infected with other respiratory viruses. Respiratory syncytial virus (RSV) and human rhinovirus (HRV) were the most common additional respiratory viruses, Lower respiratory tract infections were the most frequent diagnoses made in the hospital, in which there were 52 pneumonia (30.4%) cases. Conclusion: ADV is one of the most important pathogens of acute respiratory tract infection in children in Nanjing area, and adenovirus type 3 was the most prevalent serotype. It is important to develop long-term surveillance.

Ci L.,Rice University | Song L.,Rice University | Jin C.,Japan National Institute of Advanced Industrial Science and Technology | Jariwala D.,Rice University | And 11 more authors.
Nature Materials | Year: 2010

Two-dimensional materials, such as graphene and monolayer hexagonal BN (h-BN), are attractive for demonstrating fundamental physics in materials and potential applications in next-generation electronics. Atomic sheets containing hybridized bonds involving elements B, N and C over wide compositional ranges could result in new materials with properties complementary to those of graphene and h-BN, enabling a rich variety of electronic structures, properties and applications. Here we report the synthesis and characterization of large-area atomic layers of h-BNC material, consisting of hybridized, randomly distributed domains of h-BN and C phases with compositions ranging from pure BN to pure graphene. Our studies reveal that their structural features and bandgap are distinct from those of graphene, doped graphene and h-BN. This new form of hybrid h-BNC material enables the development of bandgap-engineered applications in electronics and optics and properties that are distinct from those of graphene and h-BN. © 2010 Macmillan Publishers Limited. All rights reserved.

Pan S.,Lanzhou University of Technology | Lin G.,Lanzhou University
Nonlinear Analysis: Real World Applications | Year: 2011

This paper is concerned with the spreading speeds and traveling wavefronts of second order integrodifference equations with local monotonicity. By introducing two auxiliary integrodifference equations, the spreading speed and traveling wave solutions are studied. In particular, we obtain the nonexistence of monotone traveling wave solutions for an example if it is local monotone. These results are applied to a model which is obtained by introducing the spatial variable to a difference equation used by the International Whaling Commission. © 2010 Published by Elsevier Ltd. All rights reserved.

Wei F.X.,Lanzhou University
Surgical Laparoscopy, Endoscopy and Percutaneous Techniques | Year: 2015

PURPOSE:: To perform a meta-analysis of randomized controlled trials (RCTs) comparing transabdominal preperitoneal (TAPP) with totally extraperitoneal (TEP) in regards of hernia recurrence, pain scores, operation time, time to return to usual activities, length of hospital stay, and total complications.MATERIALS AND METHODS:: Online databases including Pubmed, Embase and the Cochrane Library were searched with terms “hernia repair,” “totally extraperitoneal (TEP) repair,” and “transabdominal preperitoneal (TAPP) repair,” as well as the medical subject headings. Relevant RCTs were further analyzed using the methods recommended by the Cochrane Collaboration.RESULTS:: A total of 10 RCTs enrolling 1047 patients were included. There was no significant difference in terms of hernia recurrence, pain scores, operation time, time to return to usual activities, hospital stay, total complications, and cost between the 2 groups. Subgroup analysis revealed that pain scores would be affected by many clinical factors, operation time was mainly determined by state and surgeon’s experience.CONCLUSIONS:: On the basis of current evidence, TEP as a modified and more complex laparoscopic procedure than TAPP, did not lead to a significant difference in aspects of clinical outcomes and complications. Therefore, we firstly recommended TAPP for laparoscopic hernia repair, especially for nonexpert surgeons. Further choices would be made according to the specific clinical characteristics of patients and surgeons. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Cheon H.,Cleveland Clinic | Yang J.,Cleveland Clinic | Yang J.,Lanzhou University | Stark G.R.,Cleveland Clinic
Journal of Interferon and Cytokine Research | Year: 2011

The signal transducers and activators of transcription (STAT)1 and STAT3 genes are specifically activated by phosphorylated STATs 1 and 3, respectively, resulting in large and prolonged increases in the levels of unphosphorylated STATs (U-STATs) in response to interferons (for STAT1) or ligands that activate gp130, such as IL-6 (for STAT3). U-STATs 1 and 3 are transcription factors that drive gene expression by mechanisms distinct from those used by phosphorylated STATs. U-STAT3 drives expression of many proteins not induced by phospho-STAT3, including several that are important in tumorigenesis. U-STAT1 prolongs and increases expression of a subset of proteins induced initially in response to phospho-STAT1, leading to antiviral and immune responses that are long-lived. U-STAT1 levels are also high in some cancers, and the protein products of genes induced by U-STAT1 enhance resistance to DNA damage. Therefore, interferons not only drive short-term expression of proteins that inhibit growth and promote apoptosis and immune surveillance, but also promote long-term expression of proteins that facilitate tumor survival. © Copyright 2011, Mary Ann Liebert, Inc. 2011.

Xie E.,Lanzhou University
Applied Physics A: Materials Science and Processing | Year: 2010

ZnO nanoparticles were synthesized by a sol- gel calcination process following being annealed in air at 400, 600, 800 and 1000°C. X-ray diffraction pattern and X-ray photoelectron spectroscopy show that all the samples present a typical wurtzite structure and no other impurity phases are observed. Room-temperature ferromagnetism from all the samples is confirmed by the vibrating sample magnetometer measurements, which shows that the RTFM decreases with the annealing temperature increasing from 400 to 800°C, and then became larger for the sample annealed at 1000°C. According to the Raman scattering spectra and electron paramagnetic resonance, the RTFM of samples annealed at 600, 800 and 1000°C might be related to the oxygen vacancy related defects. However, the RTFM from the sample annealed at 400°C, presenting nearly the same value as that of the sample annealed at 1000°C, could originate with the interstitial zinc defects associated with XPS and photoluminescence analyses. © Springer-Verlag 2010.

In this paper, we synthesized a novel Re(I) complex of Re(CO) 3Br(PBI-Cab) owing a diamine ligand of 9-(4-(2-(pyridin-2-yl)-1H- benzo[d]imidazol-1-yl)butyl)-9H-carbazole (PBI-Cab), where the carbazole moiety was connected by an alkyl chain, hoping to realize an optical sensor immune to surrounding interference. The geometric and electronic structures were revealed by single crystal and density functional theory calculation, which indicated that the carbazole moiety played as a shield for the emissive center. Re(CO)3Br(PBI-Cab) was proved to be a promising oxygen-sensing probe owing to the immunity of emission towards surrounding interference, proper emissive energy and long excited state lifetime. By doping Re(CO) 3Br(PBI-Cab) into a polymer host of poly(vinylpyrrolidone), the oxygen sensing performance of the resulting composite material was obtained and discussed. Finally, a high sensitivity of 20.53 was achieved, with a short response/recovery time of 6 s/28 s. © 2013 Elsevier B.V.

He J.,CAS Lanzhou Institute of Modern Physics | He J.,Lanzhou University | He J.,CAS Institute of Theoretical Physics
Nuclear Physics A | Year: 2014

Based on the high precision experimental data released by the CLAS Collaboration recently, the interaction mechanism of the photoproduction of Λ(1520) off a proton target is investigated within a Regge-plus-resonance approach. With the decay amplitudes predicted in the constituent quark model, the roles played by nucleon resonances are studied. It is found that N(2120) provides the most important contribution among the nucleon resonances predicted in the constituent quark model. The t channel contribution with Regge trajectories and the Λ intermediate u channel are responsible to the behaviors of the differential cross section at forward and backward angles, respectively. © 2014 Elsevier B.V.

Che J.,Nanchang Institute of Technology | Wang J.,Lanzhou University | Wang G.,East China Jiaotong University | Wang G.,Baoshan College
Energy | Year: 2012

Electric load forecasting is an important task in the daily operations of a power utility associated with energy transfer scheduling, unit commitment and load dispatch. Inspired by the various non-linearity of electric load data and the strong learning capacity of support vector regression (SVR) for small sample and balanced data, this paper presents an adaptive fuzzy combination model based on the self-organizing map (SOM), the SVR and the fuzzy inference method. The adaptive fuzzy combination model can effectively count for electric load forecasting with good accuracy and interpretability at the same time. The key idea behind the combination is to build a human-understandable knowledge base by constructing a fuzzy membership function for each homogeneous sub-population. The comparison of different mathematical models and the effectiveness of the presented model are shown by the real data of New South Wales electricity market. The obtained results confirm the validity of the developed model. © 2011 Elsevier Ltd.

Zhang F.,Henan University | Liu B.,Lanzhou University
Journal of Alloys and Compounds | Year: 2012

The red-emitting phosphors Ca 3Gd 7(SiO 4) 5(PO 4)O 2:Eu 3+ were synthesized and their photoluminescence properties under near-ultraviolet (NUV) light excitation were investigated. The results indicate that Ca 3Gd 7(SiO 4) 5(PO 4)O 2:Eu 3+ can be effectively excited by 393 nm which matches with the emission wavelength of NUV chips for white light emitting diodes (LED). These phosphors present an intensity red emission with maximum at 614 nm. Among them, the optimal sample has high emission intensity and exhibits small thermal-quenching property, which indicates that it can be potentially applied in NUV InGaN-based LEDs. © 2012 Elsevier B.V. All rights reserved.

Chen Y.,Lanzhou University
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery | Year: 2010

Adenosine triphosphate (ATP) can promote the repair of spinal cord injury (SCI). To investigate the effect of ATP combined with bone marrow mesenchymal stem cells (BMSCs) transplantation on SCI, and to evaluate the synergistic action of ATP and BMSCs in the repair of SCI and the feasibility of the combined transplantation in the treatment of SCI. BMSCs were isolated from the marrow of the tibia and the femur of a male SD rat (weighing 120 g), the 3rd generation BMSCs were labeled with BrdU, then BMSCs suspension of 5.0 x 10(7) cell/mL were prepared. Forty-eight adult female SD rats (weighing 240-260 g) were made SCI models at T2 levels according to the improved Allen's method, and were randomly divided into 4 groups (groups A, B, C, and D, n = 12). In group A, ATP (40 mg/kg) and BMSCs (6 microL) were injected to the central point and the other 2 points which were 1 mm from the each side of head and tail of the injured spinal cord; after blending the BMSCs suspension, the cells amount was about 3.0 x 10(5). In groups B, C, and D, the BMSCs suspension (6 microL), ATP (40 mg/kg), and PBS (40 mg/kg) were injected to the points by the same method as group A, respectively. The general conditions of the rats were observed after operation. The nerve function of low extremities was evaluated using the improved Tarlov scale and the Rivlin inclined plane test at 1, 3, 7, 14, 21, and 28 days after operation. At 28 days after operation, the reparative effect of SCI was observed using histological and immunohistochemical staining. One rat of group A, 2 of group B, 2 of group C, and 3 of group D died of infection and anorexic, the others survived to the end of the experiment. Paralysis symptom in low extremities occurred in all rats after operation and was improved at 2-3 weeks postoperatively, the improvement of group A was the best, groups B and C were better, group D was the worst. There was no significant difference in the Tarlov scale and the Rivlin inclined plane test among 4 groups at 1 and 3 days after operation and between groups B and C at 7, 14, 21, and 28 days after operation (P > 0.05), but there were significant differences among other groups at 7, 14, 21, and 28 days after operation (P < 0.05). At 28 days after operation, HE staining demonstrated that the injured region in group A was finely restored, without obvious scar tissue and cavity, and there existed clear stem cell differentiation characters; there was small amount of scar tissue and cavity in the injury site of groups B and C; and there was great deal of scar tissue in the injury site of group D, in which there were numerous inflammatory cells and fibroblasts infiltration and bigger cavity. Immunohistochemical staining showed that BrdU-positive BMSCs were seen in groups A and B, and positive cells of group A was significantly more than that of group B (P < 0.05). The expressions of neurofilament protein 200 and glial fibrillary acidic protein in group A were significantly higher than those in groups B, C, and D, and groups B and C were significantly higher than group D (P < 0.05). ATP has protective effects on injured spinal cord, a combination of ATP and BMSCs can synergistically promote the reparation of SCI.

Guo H.,Xidian University | Xie Q.-Y.,Lanzhou University | Fu C.-E.,Xian Jiaotong University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Localization of a spin-1/2 fermion on the braneworld is an important and interesting problem. It is well known that a five-dimensional free massless fermion Ψ minimally coupled to gravity cannot be localized on the Randall-Sundrum braneworld. In order to trap such a fermion, the coupling between the fermion and bulk scalar fields should be introduced. In this paper, localization and quasilocalization of a bulk fermion on the thick braneworld generated by two scalar fields (a kink scalar φ and a dilaton scalar π) are investigated. Two types of couplings between the fermion and two scalars are considered. One coupling is the usual Yukawa coupling -ηΨ¯φΨ between the fermion and kink scalar, another one is λΨ¯ΓM∂Mπγ5Ψ between the fermion and dilaton scalar. The left-chiral fermion zero mode can be localized on the brane, and both the left- and right-chiral fermion massive Kaluza-Klein modes may be localized or quasilocalized. Hence the four-dimensional massless left-chiral fermion and massive Dirac fermions, whose lifetime is infinite or finite, can be obtained on the brane. © 2015 American Physical Society.

Yang L.,Lanzhou University
Nonlinear Analysis: Real World Applications | Year: 2012

We consider the dynamical behavior of the reaction-diffusion equation with nonlinear boundary condition for both autonomous and non-autonomous cases. For the autonomous case, under the assumption that the internal nonlinear term f is dissipative and the boundary nonlinear term g is non-dissipative, the asymptotic regularity of solutions is proved. For the non-autonomous case, we obtain the existence of a compact uniform attractor in H1(Ω) with dissipative internal and boundary nonlinearities. © 2011 Elsevier Ltd. All rights reserved.

Yu X.,Kunming University of Science and Technology | Xu X.,Lanzhou University | Qiu J.,Kunming University of Science and Technology
Materials Research Bulletin | Year: 2011

We report the observation of long lasting red phosphorescence in Sr 2SnO4:Sm3+ and Sr2SnO 4:Sm3+, Dy3+ phosphors. The decay patterns of afterglow curves demonstrate that the afterglow time of Sr2SnO 4:Sm3+ could be prolonged by the incorporation of Dy 3+. The remarkable changes in the thermoluminescence glow curve exhibited that the first band responsible for the origin of the afterglow becomes the most prominent feature when Dy3+ added. In other words, the enhancement of the red afterglow in Sr2SnO4:Sm 3+, Dy3+ compared with Sr2SnO 4:Sm3+ could be ascribed to more appropriate traps (the hole-traps V″Sr) created by the incorporation of Dy3+. © 2010 Elsevier Ltd © 2011 Elsevier Ltd. All rights reserved.

Cheng X.,Lanzhou University | Lu H.,Hohai University
Nonlinear Analysis: Real World Applications | Year: 2012

In this paper, we establish the product formula for the fixed point index on product cone, and the relation between LeraySchauder degree and a pair of strict lower and upper solutions for a (p 1,p 2)-Laplacian system. Based on the product formula of the fixed point index and LeraySchauder degree theory, we deal with the multiplicity of positive solutions for a class of (p 1,p 2)-Laplacian systems. As applications, we prove the global existence of positive solutions for a multi-parameter system of (p 1,p 2)-Laplacian equations with respect to parameters. © 2012 Elsevier Ltd. All rights reserved.

Zhang J.M.,Lanzhou University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2010

To study the chemical constituents from pine needles of Cedrus deodara. Chemical constituents were isolated by silica gel and Sephadex LH-20 column chromatography. The structures of the isolated compounds were elucidated through spectroscopic analysis. The compounds were identified as 9-hydroxy-dodecanoic acid (I), ethyl laurate (II), ethyl stearate (III), 3beta-hydroxy-oleanolic acid methyl ester (IV), beta-sitosterol (V), shikimic acid (VI), methylconiferin (VII), ferulic acid beta-glucoside (VIII). Compounds I-IV, VI-VIII are isolated and identified from this genus for the first time, compound V is isolated from pine needles of this genus for the first time.

Ling Y.-Q.,Lanzhou University
Chinese Journal of Tissue Engineering Research | Year: 2013

Background: Tumor is serious harmful to human health, and the application of effective chemical drug therapy has great significance. Objective: To analyze the mechanism and the therapeutic effect of drug-loaded chitosan sustained-release system on the treatment of tumor. Methods: The mechanism and the therapeutic effect of drug-loaded chitosan sustained-release system on the treatment of tumor was analyzed, as well as the characteristics and anti-tumor effect of chitosan and various chitosan-loaded anti-tumor drugs, such as doxorubicin, epirubicin, epirubicin, 5-fluorouracil and paclitaxel.Results and Conclusion: Chitosan anti-tumor-sustained release drug materials have good drug release properties and anti-tumor properties, it can load variety of commonly used antitumor drugs, control the drug release rate, extend the drug action time, maintain the effective drug concentration and decrease the toxicity and side effects of drugs, it also has targeting effect on tumor and tissues and organs, and it can increase the therapeutic effect of chemotherapeutic drugs on tumor significantly.

Wei D.F.,Lanzhou University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2012

To compare the regulating effects of Hedysari Radix and Astragali Radix alternative classic tonification prescriptions on humoral immunity in immunosuppressed mice. The immunosuppressed mouse model was induced by cyclophosphamide. The mice were administered intragastically with same dose of Hedysari Radix and Astragali Radix alternative Buzhong Yiqi Yiqi Yangxue,Yupingfeng oral liquid and Fuqi Zhihan granules for antagonistic experiments in vivo. And spleen index, HC50, CD19+B lymphocyte subgroup and content of serum IL-4 were determined after treatment. Both groups of Hedyseri Radix and Astragali Radix could antagonize immunosuppressive action caused by cyclophosphamide. They both could significantly raise spleen index, HC50, CD19+ B lymphocyte subgroup and content of serum IL4 in different degree. And Yupingfeng aqueous extract of Hedysari Radix substitute Astragali Radix was better than Yupingfeng oral liquid in raising spleen index. There were no significant differences among the rest Hedysari Radix and Astragali Radix alternative groups. Hedysari Radix compatibility with other drugs compared with original prescription has similar role in humoral immunity regulation.

Feng J.,Lanzhou University
PloS one | Year: 2013

Populus is an ecologically and economically important genus of trees, but distinguishing between wild species is relatively difficult due to extensive interspecific hybridization and introgression, and the high level of intraspecific morphological variation. The DNA barcoding approach is a potential solution to this problem. Here, we tested the discrimination power of five chloroplast barcodes and one nuclear barcode (ITS) among 95 trees that represent 21 Populus species from western China. Among all single barcode candidates, the discrimination power is highest for the nuclear ITS, progressively lower for chloroplast barcodes matK (M), trnG-psbK (G) and psbK-psbI (P), and trnH-psbA (H) and rbcL (R); the discrimination efficiency of the nuclear ITS (I) is also higher than any two-, three-, or even the five-locus combination of chloroplast barcodes. Among the five combinations of a single chloroplast barcode plus the nuclear ITS, H+I and P+I differentiated the highest and lowest portion of species, respectively. The highest discrimination rate for the barcodes or barcode combinations examined here is 55.0% (H+I), and usually discrimination failures occurred among species from sympatric or parapatric areas. In this case study, we showed that when discriminating Populus species from western China, the nuclear ITS region represents a more promising barcode than any maternally inherited chloroplast region or combination of chloroplast regions. Meanwhile, combining the ITS region with chloroplast regions may improve the barcoding success rate and assist in detecting recent interspecific hybridizations. Failure to discriminate among several groups of Populus species from sympatric or parapatric areas may have been the result of incomplete lineage sorting, frequent interspecific hybridizations and introgressions. We agree with a previous proposal for constructing a tiered barcoding system in plants, especially for taxonomic groups that have complex evolutionary histories (e.g. Populus).

Li K.,Sun Yat Sen University | Zhang L.-Y.,Sun Yat Sen University | Yan C.,Sun Yat Sen University | Wei S.-C.,Sun Yat Sen University | And 4 more authors.
Journal of the American Chemical Society | Year: 2014

Stepwise synthesis of nanosized Pd-Ru heteronuclear metal-organic cages from predesigned redox- and photo-active Ru(II)-metalloligand and naked Pd(II) ion is described. The resulting cage shows rhombododecahedral shape and contains a 5350 Å3 cavity and 12 open windows, facilitating effective trapping of both polar and nonpolar guest molecules. Protection of photosensitive guests against UV radiation is studied. © 2014 American Chemical Society.

Wang C.,Lanzhou University
Journal of Alloys and Compounds | Year: 2013

Magnetic ZnFe2O4/graphene composite (ZnFe 2O4/G) has been successfully synthesized by a facile one-pot solvothermal method. Graphene oxide (GO) was reduced to graphene and the ZnFe2O4 particles were simultaneously grown on the graphene sheets under the conditions generated in the solvothermal system. Importantly, the ZnFe2O4/G composite showed powerful visible-light-photocatalytic activity for the degradation of Rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) in the presence of H 2O2. The ZnFe2O4/G composite serves a dual function as the catalyst for photoelectrochemical degradation of dyes and the generator of a strong oxidant hydroxyl radical (OH) via photoelectrochemical decomposition of H2O2 under visible light irradiation. ZnFe2O4/G composite has excellent magnetic properties, which makes it magnetically recyclable in a suspension system. Therefore, the ZnFe2O4/G magnetic composite may find potential applications in dye water treatment and the degradation of organic dyes. © 2013 Elsevier B.V. All rights reserved.

Jin J.,CAS Lanzhou Institute of Chemical Physics | Jin J.,University of Chinese Academy of Sciences | Fu X.,CAS Lanzhou Institute of Chemical Physics | Fu X.,Lanzhou University | And 6 more authors.
ACS Nano | Year: 2013

Nitrogen-doped graphene sheets (NGS), synthesized by annealing graphite oxide (GO) with urea at 700-1050 C, were studied as positive electrodes in a vanadium redox flow battery. The NGS, in particular annealed at 900 C, exhibited excellent catalytic performance in terms of electron transfer (ET) resistance (4.74 ± 0.51 and 7.27 ± 0.42 Ω for the anodic process and cathodic process, respectively) and reversibility (ΔE = 100 mV, I pa/Ipc = 1.38 at a scan rate of 50 mV s-1). Detailed research confirms that not the nitrogen doping level but the nitrogen type in the graphene sheets determines the catalytic activity. Among four types of nitrogen species doped into the graphene lattice including pyridinic-N, pyrrolic-N, quaternary nitrogen, and oxidic-N, quaternary nitrogen is verified as a catalytic active center for the [VO]2+/[VO2] + couple reaction. A mechanism is proposed to explain the electrocatalytic performance of NGS for the [VO]2+/[VO 2]+ couple reaction. The possible formation of a N-V transitional bonding state, which facilitates the ET between the outer electrode and reactant ions, is a key step for its high catalytic activity. © 2013 American Chemical Society.

Long S.,University of Kentucky | Zhou P.,Lanzhou University | Parkin S.,University of Kentucky | Li T.,Purdue University
Crystal Growth and Design | Year: 2014

Carboxylic acid-acid hydrogen-bonding dimer and acid-pyridine hydrogen-bonding motif are two competing supramolecular synthons that a molecule possessing both carboxylic acid and pyridine functional groups could form in the solid state. Their coexistence has been observed but for the molecules with the molar ratio of carboxylic acid and pyridine groups being greater than 1:1. In this crystal engineering study, 2-[phenyl(propyl)amino]nicotinic acid with a 1:1 molar ratio of these two functional groups was discovered to have two polymorphs, in which one consists of unique hydrogen-bonded tetramer units bearing both acid-acid and acid-pyridine hydrogen-bonding motifs, while the other is composed of acid-pyridine hydrogen-bonded chains. Quantum mechanical calculations were employed to unravel the essence of the coexistence of the two vying counterparts as well as the origins of the tetramer and chain structures. © 2013 American Chemical Society.

Qiu Q.-S.,Lanzhou University
Journal of Genetics and Genomics | Year: 2012

Membrane fusion is the last step in trafficking pathways during which membrane vesicles fuse with target organelles to deliver cargos. It is a central cellular reaction that plays important roles in signal transduction, protein sorting and subcellular compartmentation. Recent progress in understanding the roles of ion transporters in vacuole fusion in yeast is summarized in this article. It is becoming increasingly evident that the vacuolar proton pump V-ATPase and vacuolar Na +/H + antiporter ScNhx1p are key components of the vacuole fusion machinery in yeast. Yeast ScNhx1p regulates vacuole fusion by controlling the luminal pH. V-ATPases serve a dual role in vacuolar integrity in which they regulate both vacuole fusion and fission reactions in yeast. Fission defects are epistatic to fusion defects. Vacuole fission depends on the proton translocation activity of the V-ATPase; by contrast, the fusion reaction does not need the transport activity but requires the physical presence of the proton pump. V 0, the membrane-integral sector of the V-ATPase, forms trans-complexes between the opposing vacuoles in the terminal phase of vacuole fusion where the V 0 trans-complexes build a continuous proteolipid channel at the fusion site to mediate the bilayer fusion. © 2012 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China.

On the basis of a vacancy-squashing model for melting that we developed recently, a vacancy formed in the premelting liquid-like-layer is proposed to be squashed at the instance of its formation, which will significantly facilitate vacancy formation. Accordingly, the temperature for surface-induced melting and its size dependence are quantitatively calculated. By comparing the calculated data with the reported experimental results for metals, we show that the present approach may potentially predict the size-dependent melting point of other metals. © 2013 Copyright Taylor and Francis Group, LLC.

Jiao H.Y.,Northwest University for Nationalities | Wang Y.,Lanzhou University
Physica B: Condensed Matter | Year: 2012

A novel red-emitting phosphor CaSrAl 2SiO 7:Eu 3 was firstly synthesized through the high temperature solid state reaction at 1300°C. The structure, diffuse reflection spectra, photoluminescence spectra, color-coordinate parameters and quantum efficiencies (QE) of phosphors were investigated. The obtained CaSrAl 2SiO 7:Eu 3 phosphors have the same structure with that of the Ca 2Al 2SiO 7 and Sr 2Al 2SiO 7 phosphor, which have the melilite structure. Optical properties were studied as a function of Eu 3 concentration x, when x>0.14, the intensity of absorption of the f-f transitions of Eu 3 at 393 nm is stronger than that of the broad charge transfer transition band (CTB) around 254 nm, and which matches well with the output lights of NUV-LEDs, whereas, the concentration of Eu 3 x≤0.14, the absorption of 393 nm is weaker than that of CTB. The underlying reason of Eu 3 concentration on their luminescent properties was investigated and discussed in detail. As a result, comparing with the commercial red phosphor Y 2O 2S:Eu 3, the CaSrAl 2SiO 7:xEu 3 (x>0.14) phosphor exhibited excellent color purity and much higher brightness and could be considered as promising red phosphors for NUV-LEDs. © 2012 Published by Elsevier B.V. All rights reserved.

Feng C.-F.,Wuhan Textile University | Wang Y.-H.,Lanzhou University
Communications in Theoretical Physics | Year: 2012

In this paper, we propose a method for the projective synchronization between two different chaotic systems with variable time delays. Using active control approach, the suitable controller is constructed to make the states of two different diverse time delayed systems asymptotically synchronize up to the desired scaling factor. Based on the Lyapunov stability theory, the sufficient condition for the projective synchronization is calculated theoretically. Numerical simulations of the projective synchronization between Mackey - Glass system and Ikeda system with variable time delays are shown to validate the effectiveness of the proposed algorithm. © 2012 Chinese Physical Society and IOP Publishing Ltd.

Fu Q.,University of Washington | Fu Q.,Lanzhou University | Solomon S.,National Oceanic and Atmospheric Administration | Lin P.,University of Washington
Atmospheric Chemistry and Physics | Year: 2010

This study examines the seasonality of tropical lower-stratospheric temperature trends using the Microwave Sounding Unit lower-stratospheric channel (T4) for 1980-2008. We present evidence that this seasonality is largely a response to changes in the Brewer-Dobson circulation (BDC) driven by extratropical wave forcing. We show how the tropical T4 trend can be used as an indicator of changes in the BDC, and find that the BDC is strengthening for 1980-2008 in June-November related to the Southern Hemisphere (SH) and in December-February to the Northern Hemisphere (NH). In marked contrast, we find that the BDC is weakening in March-May, apparently because of a weakening of its northern cell. The novel observational evidence on the seasonal dependence of the BDC trends presented in this study has important implications for the understanding of climate change in the stratosphere as well as testing climate model simulations. © Author(s) 2010.

Wu Q.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhang T.,Lanzhou University | Zhang T.,University of Colorado at Boulder | Liu Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute
Cryosphere | Year: 2012

In this study, we investigated changes in active layer thickness (ALT) and permafrost temperatures at different depths using data from the permafrost monitoring network along the Qinghai-Xizang (Tibet) Railway (QXR) since 2005. Among these sites, mean ALT is ∼3.1 m, with a range of ∼1.1 to 5.9 m. From 2006 through 2010, ALT has increased at a rate of ∼6.3 cm a -1. The mean rate of permafrost temperature rise at the depth of 6.0 m is ∼0.02 °C a-1, estimated by linear regression using 5 yr of data, and the mean rate of mean annual ground temperature (MAGT) rise at a depth of zero amplitude is ∼0.012 °C a-1. Changes for colder permafrost (MAGT <-1.0 °C) are greater than changes for relatively warmer permafrost (MAGT >-1.0 °C). This is consistent with results observed in the Arctic and subarctic. © 2012 Author(s).

Thorsen T.J.,University of Washington | Fu Q.,University of Washington | Fu Q.,Lanzhou University
Journal of Atmospheric and Oceanic Technology | Year: 2015

A feature detection and extinction retrieval (FEX) algorithm for the Atmospheric Radiation Measurement Program's (ARM) Raman lidar (RL) has been developed. Presented here is Part II of the FEX algorithm: the retrieval of cloud and aerosol extinction profiles. The directly retrieved extinction profiles using the Raman method are supplemented by other retrieval methods developed for elastic backscatter lidars. Portions of features where the extinction-to-backscatter ratios (i.e., lidar ratios) can be obtained are used to infer the lidar ratios for the regions where no such estimate can be made. When neither directly retrieved nor an inferred value can be determined, a climatological lidar ratio is used. This best-estimate approach results in the need to use climatological lidar ratios for less than about 5% of features, except for thin cirrus at the ARM tropical western Pacific Darwin site, where above 12 km, about 20% of clouds use a climatological lidar ratio. A classification of feature type is made, guided by the atmosphere's thermodynamic state and the feature's scattering properties: lidar ratio, backscatter, and depolarization. The contribution of multiple scattering is explicitly considered for each of the ARM RL channels. A comparison between aerosol optical depth from FEX and that from collocated sun photometers over multiple years at two ARM sites shows an agreement (in terms of bias error) of about -0.3% to -4.3% (relative to the sun photometer). © 2015 American Meteorological Society.

Feng J.,CAS Institute of Atmospheric Physics | Feng J.,Lanzhou University | Li J.,CAS Institute of Atmospheric Physics | Li Y.,CSIRO
Journal of Climate | Year: 2010

Previous studies have raised the possibility that the recent decline in winter rainfall over southwest Western Australia (SWWA) is related to the concurrent upward trend in the southern annular mode (SAM). On the basis of an analysis of 60-yr (1948-2007) reanalysis and observed data, the authors suggest that the apparent inverse relationship between the SAM and SWWA winter rainfall (SWR) is caused by a single extreme year-1964. It is shown that both the negative and positive phases of the SAM have little impact on SWR in the case that data for 1964 are excluded from the analysis. In addition, for periods prior to and after 1964 in the case that data for 1964 are excluded, the apparent relationship between the SAM and SWR becomes insignificant, and the circulation anomalies with respect to SWR appear to be an SAM-like pattern for which the anomalies at high latitudes are not significant. The result indicates that the SAM does not significantly influence the winter rainfall over SWWA. Instead, the variation of SWR would be more closely linked to the variability in regional circulations. © 2010 American Meteorological Society.

Feng J.,Lanzhou University | Li J.,CAS Institute of Atmospheric Physics | Li Y.,CSIRO
Journal of Climate | Year: 2010

Using the NCEP-NCAR reanalysis, the 40-yr ECMWF Re-Analysis (ERA-40), and precipitation data from the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the Australian Bureau of Meteorology, the variability and circulation features influencing southwest Western Australia (SWWA) winter rainfall are investigated. It is found that the climate of southwest Australia bears a strong seasonality in the annual cycle and exhibits a monsoon-like atmospheric circulation, which is called the southwest Australian circulation (SWAC) because of its several distinct features characterizing a monsoonal circulation: the seasonal reversal of winds, alternate wet and dry seasons, and an evident land-sea thermal contrast. The seasonal march of the SWAC in extended winter (May-October) is demonstrated by pentad data. An index based on the dynamics' normalized seasonality was introduced to describe the behavior and variation of the winter SWAC. It is found that the winter rainfall over SWWA has a significant positive correlation with the SWAC index in both early (May-July) and late (August-October) winter. In weaker winter SWAC years, there is an anticyclonic anomaly over the southern Indian Ocean resulting in weaker westerlies and northerlies, which are not favorable for more rainfall over SWWA, and the opposite combination is true in the stronger winter SWAC years. The SWAC explains not only a large portion of the interannual variability of SWWA rainfall in both early and late winter but also the long-term drying trend over SWWA in early winter. The well-coupled SWAC-SWWA rainfall relationship seems to be largely independent of the well-known effects of large-scale atmospheric circulations such as the southern annular mode (SAM), El Niño-Southern Oscillation (ENSO), Indian Ocean dipole (IOD), and ENSO Modoki (EM). The result offers qualified support for the argument that the monsoon-like circulation may contribute to the rainfall decline in early winter over SWWA. The external forcing of the SWAC is also explored in this study. © 2010 American Meteorological Society.

Zheng Y.,CAS Lanzhou Institute of Chemical Physics | Zheng Y.,Lanzhou University | Wang A.,CAS Lanzhou Institute of Chemical Physics
European Polymer Journal | Year: 2015

Hydrogels are 3D networks of polymer chains that are crosslinked via either physical or chemical bonds. A strong repulsive force is generated among those abundant functional groups with the same charge, which enables the hydrogels to be initially applied as the superabsorbent materials. Recent studies have found that the hydrogel adsorbents show superhigh adsorption capacities, fast adsorption rate, wide pH-independence, easy regeneration and reusable ability, by which the hydrogels are given the appellation "superadsorbent". The limitations of traditional bulk hydrogel make granular hydrogel have received much attention in recent years. Therefore, the purpose of this review is to organize the scattered available information on the focus of polymerization strategies for the formation of granular hydrogels, with the scope limited to the crosslinked hydrogels via polymerization using one or more vinyl monomers. Furthermore, some of the important applications of hydrogel as the superadsorbents for removing various pollutants since 2000 are summarized and discussed, regardless of its form in either bulk or granular. An extensive list of hydrogel adsorbents has been compiled and selected studies with adsorption capacities for heavy metals including radioactive and rare earth metals, dyes and eutrophic substances as available in the literature are presented, with the key advancements of this type of novel adsorbents are briefly addressed. The facile synthesis and energy savings offer them a lot of promising benefits for commercial purposes in the future. © 2015 Elsevier Ltd.

Huang Y.,Lanzhou University | Ng M.,Hong Kong Baptist University | Zeng T.,Hong Kong Baptist University
Communications in Computational Physics | Year: 2013

In this paper, we consider variational approaches to handle the multiplicative noise removal and deblurring problem. Based on rather reasonable physical blurring-noisy assumptions, we derive a new variational model for this issue. After the study of the basic properties, we propose to approximate it by a convex relaxation model which is a balance between the previous non-convex model and a convex model. The relaxed model is solved by an alternating minimization approach. Numerical examples are presentedto illustrate the effectivenessand efficiencyof the proposed method. © 2013 Global-Science Press.

Yao J.,Zhejiang University | Feng R.,Zhejiang University | Wu Z.,Zhejiang University | Liu Z.,Zhejiang University | And 2 more authors.
Advanced Synthesis and Catalysis | Year: 2013

An efficient palladium-catalyzed decarboxylative ortho-acylation of 2-aryloxypyridines with α-oxocarboxylic acids is described. In this new transformation, the aromatic C(sp2)-H bond was successfully acylated to give diverse aromatic ketones regioselectively in moderate to good yields. The pyridine group can be removed easily after the acylation to give the corresponding 2-hydroxy aromatic ketones. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ye L.,Wuhan University | Deng K.,South-Central University for Nationalities | Xu F.,Lanzhou University | Tian L.,Wuhan University | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2012

Black BiOCl with oxygen vacancies was prepared by UV light irradiation with Ar blowing. The as-prepared black BiOCl sample showed 20 times higher visible light photocatalytic activity than white BiOCl for RhB degradation. The trapping experiment showed that the superoxide radical () and holes (h+) were the main active species in aqueous solution under visible light irradiation.

The Sox (SRY-related high-mobility-group box) family of genes shares a conserved HMG box and is involved in a diverse range of developmental processes and sex determination in vertebrates. Twenty Sox genes are present in the genomes of humans and mice, but far less is known about the Sox gene family in reptiles. Using two pairs of highly degenerate primers designed from a multiple alignment of Sox amino acid sequences in several species, different positive clones were obtained from male and female Eremias multiocellata, a viviparous lizard which is subject to TSD (temperature-dependent sex determination). These clones were sequenced and identified. They are members of the SoxB (Sox2, Sox14), SoxC (Sox11, Sox12) and SoxE (Sox9a, Sox9b, Sox10) groups. No sex-specific differences were observed. Based on the amino acid sequence similarities, the phylogenetic analysis was carried out and these genes clustered with their orthologues. In addition, we found the gene duplication in E. multiocellata, it may be a mechanism to produce new functional genes.

Zhang H.F.,Lanzhou University | Lombardo U.,National Institute of Nuclear Physics, Italy | Zuo W.,CAS Lanzhou Institute of Modern Physics
Physical Review C - Nuclear Physics | Year: 2010

We present a numerical study of shear viscosity and thermal conductivity of symmetric nuclear matter, pure neutron matter, and β-stable nuclear matter, in the framework of the Brueckner theory. The calculation of in-medium cross sections and nucleon effective masses is performed with a consistent two- and three-body interaction. The investigation covers a wide baryon density range as needed in the applications to neutron stars. The results for the transport coefficients in β-stable nuclear matter are used to make preliminary predictions on the damping time scales of nonradial modes in neutron stars. © 2010 The American Physical Society.

Fu S.,Northwest Normal University | Fu S.,Guilin University of Electronic Technology | Zhang L.,Northwest Normal University | Hu P.,Lanzhou University
Nonlinear Analysis: Real World Applications | Year: 2013

In this paper, the global behavior of solutions is investigated for a Lotka-Volterra predator-prey system with prey-stage structure. First, we can see that the stability properties of nonnegative equilibria for the weakly coupled reaction-diffusion system are similar to that for the corresponding ODE system, that is, linear self-diffusions do not drive instability. Second, using Sobolev embedding theorems and bootstrap arguments, the existence and uniqueness of nonnegative global classical solution for the strongly coupled cross-diffusion system are proved when the space dimension is less than 10. Finally, the existence and uniform boundedness of global solutions and the stability of the positive equilibrium point for the cross-diffusion system are studied when the space dimension is one. It is found that the cross-diffusion system is dissipative if the diffusion matrix is positive definite. Furthermore, cross diffusions cannot induce pattern formation if the linear diffusion rates are sufficiently large. © 2013 Elsevier Ltd. All rights reserved.

Yang Y.-R.,Lanzhou Jiaotong University | Li W.-T.,Lanzhou University | Wu S.-L.,Xidian University
Nonlinear Analysis: Real World Applications | Year: 2013

This paper is concerned with traveling waves of a monostable reaction-diffusion system with delay and without quasi-monotonicity. When the initial perturbation around the traveling wave is suitably small in a weighted norm, the exponential stability of all traveling wave solutions for the system with delay is proved by the weighted energy method. © 2012 Elsevier Ltd. All rights reserved.

Wu Z.-X.,Lanzhou University | Zhang H.-F.,Anhui University
EPL | Year: 2013

Whether or not to change behavior depends not only on the personal success of each individual, but also on the success and/or behavior of others. Using this as motivation, we incorporate the impact of peer pressure into a susceptible-vaccinated-infected-recovered (SVIR) epidemiological model, where the propensity to adopt a particular vaccination strategy depends both on individual success as well as on the strategies of neighbors. We show that plugging into the peer pressure is a double-edged sword, which, on the one hand, strongly promotes vaccination when its cost is below a critical value, but, on the other hand, it can also strongly impede it if the critical value is exceeded. We explain this by revealing a facilitated cluster formation process that is induced by the peer pressure. Due to this, the vaccinated individuals are inclined to cluster together and therefore become unable to efficiently inhibit the spread of the infectious disease if the vaccination is costly. If vaccination is cheap, however, they reinforce each other in using it. Our results are robust to variations of the SVIR dynamics on different population structures. © Copyright EPLA, 2013.

Li X.,Samuel Roberts Noble Foundation | Wang X.,Lanzhou University | Wei Y.,Samuel Roberts Noble Foundation | Brummer E.C.,Samuel Roberts Noble Foundation
Theoretical and Applied Genetics | Year: 2011

Segregation distortion (SD) is often observed in plant populations; its presence can affect mapping and breeding applications. To investigate the prevalence of SD in diploid alfalfa (Medicago sativa L.), we developed two unrelated segregating F 1 populations and one F 2 population. We genotyped all populations with SSR markers and assessed SD at each locus in each population. The three maps were syntenic and largely colinear with the Medicago truncatula genome sequence. We found genotypic SD for 24 and 34% of markers in the F 1 populations and 68% of markers in the F 2 population; distorted markers were identified on every linkage group. The smaller percentage of genotypic SD in the F 1 populations could be because they were non-inbred and/or due to non-fully informative markers. For the F 2 population, 60 of 90 mapped markers were distorted, and they clustered into eight segregation distortion regions (SDR). Most SDR identified in the F 1 populations were also identified in the F 2 population. Genotypic SD was primarily due to zygotic rather than allelic distortion, suggesting zygotic not gametic selection is the main cause of SD. On the F 2 linkage map, distorted markers in all SDR except two showed heterozygote excess. The severe SD in the F 2 population likely biased genetic distances among markers and possibly also marker ordering and could affect QTL mapping of agronomic traits. To reduce the effects of SD and non-fully informative markers, we suggest constructing linkage maps and conducting QTL mapping in advanced generation populations. © 2011 Springer-Verlag.

Li Y.-M.,Kunming University of Science and Technology | Shen Y.,Kunming University of Science and Technology | Chang K.-J.,Kunming University of Science and Technology | Yang S.-D.,Lanzhou University
Tetrahedron Letters | Year: 2014

A novel arylnitration of alkenes by nitration and C-H functionalization cascade process has been developed. This methodology provides an efficient way to construct a variety of nitro-containing oxindoles and dihydroquinolin-2(1H)- ones. In addition, the process exhibits significant functional group tolerance. Moreover, the use of inexpensive and readily available starting materials makes this practical and atom-economical approach particularly attractive. © 2013 Published by Elsevier Ltd.

Ren W.,Soochow University of China | Liu J.,Soochow University of China | Chen L.,Soochow University of China | Wan X.,Soochow University of China | Wan X.,Lanzhou University
Advanced Synthesis and Catalysis | Year: 2010

Using a catalytic system of the (cymene)ruthenium dichloride dimer, [Ru(cymene)Cl2]2, (0.001 mol%) and iodine (10 mol%), a variety of alkynes bearing different functional groups were oxidized with tert-butyl hydroperoxide (TBHP; 70% solution in water) under mild conditions to give 1,2diketones in good to excellent yields. Two noteworthy features of the method are the extremely high catalyst productivity (TON up to 420,000) and scale-up to 1 mol. Preliminary mechanism investigations showed that iodonium ion and water were involved in the transformation. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Saunders R.W.,University of Leeds | Dhomse S.,University of Leeds | Tian W.S.,Lanzhou University | Chipperfield M.P.,University of Leeds | Plane J.M.C.,University of Leeds
Atmospheric Chemistry and Physics | Year: 2012

Nano-sized meteoric smoke particles (MSPs) with iron-magnesium silicate compositions, formed in the upper mesosphere as a result of meteoric ablation, may remove sulphuric acid from the gas-phase above 40 km and may also affect the composition and behaviour of supercooled H 2SO 4-H 2O droplets in the global stratospheric aerosol (Junge) layer. This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe 3+) ion originating from amorphous ferrous (Fe 2+)-based silicate powders dissolved in varying Wt % sulphuric acid (30-75 %) solutions over a temperature range of 223-295 K. Complete dissolution of the particles was observed under all conditions. The first-order rate coefficient for dissolution decreases at higher Wt % and lower temperature, which is consistent with the increased solution viscosity limiting diffusion of H 2SO 4 to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe 2+ compounds. The chemistry climate model UMSLIMCAT (based on the UKMO I Unified Model) was then used to study the transport of MSPs through the middle atmosphere. A series of model experiments were performed with different uptake coefficients. Setting the concentration of 1.5 nm radius MSPs at 80 km to 3000 cm -3 (based on rocket-borne charged particle measurements), the model matches the reported Wt % Fe values of 0.5-1.0 in Junge layer sulphate particles, and the MSP optical extinction between 40 and 75 km measured by a satellite-borne spectrometer, if the global meteoric input rate is about 20 tonnes per day. The model indicates that an uptake coefficient 0.01 is required to account for the observed two orders of magnitude depletion of H 2SO 4 vapour above 40 km. © 2012 Author(s).

Hu Y.,Georgia Institute of Technology | Zhang Y.,Georgia Institute of Technology | Zhang Y.,Lanzhou University | Chang Y.,Georgia Institute of Technology | And 2 more authors.
ACS Nano | Year: 2010

Using a metal-semiconductor-metal back-to-back Schottky contacted ZnO microwire device, we have demonstrated the piezoelectric effect on the output of a photocell. An externally applied strain produces a piezopotential in the microwire, which tunes the effective height of the Schottky barrier (SB) at the local contact, consequently changing the transport characteristics of the device. An equivalent circuit model together with the thermionic emission theory has explained the four kinds of relationships observed between the photocurrent and the applied strain. Our study shows the possibility of maximizing the output of a photocell by controlling strain in the device. © 2010 American Chemical Society.

Mu B.,CAS Lanzhou Institute of Chemical Physics | Liu P.,Lanzhou University | Wang A.,CAS Lanzhou Institute of Chemical Physics
Electrochimica Acta | Year: 2013

The polyaniline (PAn)/carbon black (CB) hybrid hollow microspheres have been prepared by the layer-by-layer assembly technique alternately adsorbing of PAn and CB onto the polystyrene sulfonate microsphere templates after etching the templates by dialysis. The hollow structure of the obtained hybrid hollow microspheres was characterized by transmission electron microscopy, which indicated that the external diameter of the hollow microspheres was about 3.0 μm. When the hybrid hollow microsphere were used as the electrode material for supercapacitors, the results showed that the specific capacitance increased with the increase in the adsorption numbers of PAn and CB, which was as high as 532 F g-1 at a charge-discharge current density of 10 mA cm -2 in 1.0 M H2SO4 electrolyte after alternately adsorbing of PAn and CB six times. © 2012 Elsevier Ltd. All rights reserved.

Sang P.,Zhejiang University | Xie Y.,Zhejiang University | Zou J.,Zhejiang University | Zhang Y.,Zhejiang University | Zhang Y.,Lanzhou University
Organic Letters | Year: 2012

An efficient synthesis of indolo[1,2-c]quinazoline derivatives has been developed by copper-catalyzed sequential Ullmann N-arylation and aerobic oxidative C-H amination. The protocol uses readily available 2-(2-halophenyl)-1H-indoles and (aryl)methanamines as the starting materials to afford indolo[1,2-c]quinazolines, which are the core units of hinckdentine A. © 2012 American Chemical Society.

Huang Y.-M.,Lanzhou University | Moisan L.,University of Paris Descartes | Ng M.K.,Hong Kong Baptist University | Zeng T.,Hong Kong Baptist University
IEEE Transactions on Image Processing | Year: 2012

Multiplicative noise removal is a challenging image processing problem, and most existing methods are based on the maximum a posteriori formulation and the logarithmic transformation of multiplicative denoising problems into additive denoising problems. Sparse representations of images have shown to be efficient approaches for image recovery. Following this idea, in this paper, we propose to learn a dictionary from the logarithmic transformed image, and then to use it in a variational model built for noise removal. Extensive experimental results suggest that in terms of visual quality, peak signal-to-noise ratio, and mean absolute deviation error, the proposed algorithm outperforms state-of-the-art methods. © 2012 IEEE.

Zhou D.-B.,Anhui University of Science and Technology | Wang G.-W.,Anhui University of Science and Technology | Wang G.-W.,Lanzhou University
Organic Letters | Year: 2015

A convenient and highly efficient palladium-catalyzed decarboxylative annulation of 2-arylbenzoic acids with [60]fullerene has been exploited to synthesize the novel and scarce [60]fullerene-fused dihydrophenanthrenes. The use of Lewis acid ZnCl2 is crucial for the success of the present formal [4 + 2] annulation reaction. Plausible reaction pathways leading to the observed products have been proposed, and the electrochemistry of the fullerene products has also been investigated. © 2015 American Chemical Society.

Lin C.,Zhejiang University | Yu W.,Zhejiang University | Yao J.,Zhejiang University | Wang B.,Zhejiang University | And 3 more authors.
Organic Letters | Year: 2015

The nickel-catalyzed β-thioetherification of unactivated C(sp3)-H bond of propionamides is established with the assistance of 8-aminoquinoline auxiliary, leading to the β-thio carboxylic acid derivatives. A broad range of functional groups is compatible with this thioetherfication reaction. The process represents the first successful example of metal-catalyzed C-S bond formation from unactivated C(sp3)-H bonds. © 2015 American Chemical Society.

Gao Q.,Central China Normal University | Zhang J.,Central China Normal University | Wu X.,Central China Normal University | Liu S.,Central China Normal University | And 2 more authors.
Organic Letters | Year: 2015

The first C3-dicarbonylation of indoles was realized through direct oxidative cross-coupling of indoles with methyl ketones in the presence of molecular iodine and pyrrolidine. This reaction constructed a highly efficient indolyl diketones scaffold, which might be regarded as a useful biological and pharmacological tool in the exploration of therapeutic A2BAR modulators. The use of inexpensive molecular iodine and pyrrolidine and a broad substrate scope make this protocol very practical. Preliminary mechanistic studies indicate that two paths are involved in this process. (Chemical Presented). © 2014 American Chemical Society.

Wang J.,Dongbei University of Finance and Economics | Dong Y.,Lanzhou University | Jiang H.,Florida State University
Energy Conversion and Management | Year: 2014

Electricity is an indispensable energy source for modern social and economic development. However, large-scale blackouts can cause incalculable loss to society. In 2012, three major Indian power grids collapsed, resulting in the interruption of the electricity supply to over 600 million people. To avoid an event like that, China needs to forecast the power generation and consumption of eight power grids effectively. This paper first analyzes the characteristics of eight power grids and then proposes a combined model based on three improved grey models optimized by a differential evolution algorithm to predict electricity production and consumption of each power grid. The optimized combined forecasting model provides a better prediction than other models, and it is also the most workable and satisfactory model. Experiment results show electricity production and consumption would increase. In consideration of the real situation and existing problems, some suggestions are proposed. The government could decrease thermal power and exploit renewable energy power, like hydroelectric power, wind power and solar power, to ensure the safe and reliable operation of China's major power grids and protect environment. © 2014 Elsevier Ltd. All rights reserved.

Shi K.,Technical University of Denmark | Hou X.,Technical University of Denmark | Roos P.,Technical University of Denmark | Wu W.,Lanzhou University
Analytical Chemistry | Year: 2012

A rapid and efficient method for the determination of 99Tc in environmental solid samples was developed using chromatographic separation combined with inductively coupled plasma mass spectrometry (ICPMS) measurement. The volatility of technetium during sample ashing and solution evaporation was investigated to establish a reliable sample pretreatment procedure. A novel approach was developed to improve the removal of molybdenum and ruthenium in chromatographic separation using 30% H 2O 2 pretreatment of the loading solution and extraction chromatographic separation using two serial small TEVA columns. The decontamination factors of more than 4 × 10 4 and 1 × 10 5 are achieved for molybdenum and ruthenium, respectively. Chemical yields of technetium in entire procedure range from 60% to 95% depending on the type and amount of samples, and the detection limit of 0.15 mBq/g for 99Tc was obtained. The method has been successfully applied for the determination of 99Tc in environmental solid samples. © 2012 American Chemical Society.

Zhang H.-F.,Anhui University | Yang Z.,University of Electronic Science and Technology of China | Wu Z.-X.,Lanzhou University | Wang B.-H.,Hefei University of Technology | Zhou T.,University of Electronic Science and Technology of China
Scientific Reports | Year: 2013

Facing the threats of infectious diseases, we take various actions to protect ourselves, but few studies considered an evolving system with competing strategies. In view of that, we propose an evolutionary epidemic model coupled with human behaviors, where individuals have three strategies: vaccination, self-protection and laissez faire, and could adjust their strategies according to their neighbors' strategies and payoffs at the beginning of each new season of epidemic spreading. We found a counter-intuitive phenomenon analogous to the well-known Braess's Paradox, namely a better condition may lead to worse performance. Specifically speaking, increasing the successful rate of self-protection does not necessarily reduce the epidemic size or improve the system payoff. The range and degree of the Braess's Paradox are sensitive to both the parameters characterizing the epidemic spreading and the strategy payoff, while the existence of the Braess's Paradox is insensitive to the network topologies. This phenomenon can be well explained by a mean-field approximation. Our study demonstrates an important fact that a better condition for individuals may yield a worse outcome for the society.

Wang X.,Lanzhou University
Cochrane database of systematic reviews (Online) | Year: 2010

BACKGROUND: Carcinoma of the uterine cervix is the second most common cancer and the third leading cause of cancer death among women. Radiotherapy has been used successfully to treat cervical cancer for nearly a century. The combination of external beam radiotherapy (EBRT) and intracavitary brachytherapy (ICBT) has become a standard treatment modality for cervical cancer. Depending on the difference in dose rate on 'Point A' (located 2 cm above the cervical os and 2 cm lateral to the central axis of the uterus), the ICBT is divided into three modalities: low dose rate (LDR), high dose rate (HDR) and medium dose rate (MDR). Despite the practical advantages of HDR, it is necessary to investigate further the efficacy and safety of HDR brachytherapy compared to LDR brachytherapy. Questions arise as to whether HDR or LDR brachytherapy improves results for patients with cervical cancer in terms of local control rates, survival and complications related to treatment. OBJECTIVES: To assess the efficacy and safety of HDR- versus LDR-ICBT for patients with uterine cervical cancer. SEARCH STRATEGY: We searched the Cochrane Gynaecological Cancer Group Specialised Register and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 4), MEDLINE (1966 to November 2009), EMBASE (1974 to November 2009), Chinese Biomedical Literature Database (CBM) (1978 to November 2009) for relevant original, published trials. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs that compared HDR- with LDR-ICBT, combined with EBRT, for patients with locally advanced uterine cervical cancer. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the data using standardised forms. Primary outcome measures included overall survival (OS), relapse-free survival (RFS) and pelvic control rate, while secondary outcomes included rates of recurrence and complications. MAIN RESULTS: Four studies involving 1265 patients met the inclusion criteria. In our meta-analysis to compare HDR and LDR, the pooled RRs were 0.95 (95% CI 0.79 to 1.15), 0.93 (95% CI 0.84 to 1.04) and 0.79 (95% CI 0.52 to 1.20) for 3-, 5- and 10-year overall survival rates; and 0.95 (95% CI 0.84 to 1.07) and 1.02 (0.88 to 1.19) for 5- and 10-year disease-specific survival (DSS) rates. The RR for RFS was 1.04 (95% CI 0.71 to 1.52) and 0.96 (95% CI 0.81 to 1.14) at three and five years. For local control rates the RR was 0.95 (95% CI 0.86 to 1.05) and 0.95 (95% CI 0.87 to 1.05) at three and five years; with a RR of 1.09 (95% CI 0.83 to 1.43) for locoregional recurrence, 0.79 (95% CI 0.40 to 1.53) for local and distance recurrence, 2.23 (95% CI 0.78 to 6.34) for para-aortic lymph node metastasis and 0.99 (95% CI 0.72 to 1.35) for distance metastasis. For bladder, rectosigmoid and small bowel complications, the RR was 1.33 (95% CI 0.53 to 3.34), 1.00 (95% CI 0.52 to 1.91) and 3.37 (95% CI 1.06 to 10.72), respectively. These results indicate that there were no significant differences except for increased small bowel complications with HDR (P = 0.04). AUTHORS' CONCLUSIONS: This review showed no significant differences between HDR- and LDR-ICBT when considering OS, DSS, RFS, local control rate, recurrence, metastasis and treatment related complications for women with cervical carcinoma. Due to some potential advantages of HDR-ICBT (rigid immobilization, outpatient treatment, patient convenience, accuracy of source and applicator positioning, individualized treatment) we recommend the use of HDR-ICBT for all clinical stages of cervix cancer.

Zhai Y.,Xian University of Arts and Science | He Q.,Lanzhou University | Han Q.,Xian University of Arts and Science | Duan S.,Xian University of Arts and Science
Microchimica Acta | Year: 2012

We have modified silica-coated Fe 3O 4 nanoparticles with 2,6-diaminopyridine and used these for selective magnetic solid-phase extraction of trace amounts of metal ions. The nanoparticles were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Quantitative extraction of trace amounts of Cu(II) and Zn(II) from mixed-ion solutions was accomplished at an optimal pH value of 6 within less than 10 min. The metal ions were eluted from the sorbent with hydrochloric acid. Common electrolytes and chemically related metal ions do not interfere. The relative standard deviations of the method are <4 %. It was successfully applied to the separation and preconcentration of trace metal ions from the certified reference materials GBW 08301 (river sediment) and GBW 08607 (water solution), in natural water, and in samples of vegetable with satisfying results. © 2012 Springer-Verlag.

Wang L.,Lanzhou University
Journal of Non-Crystalline Solids | Year: 2015

After a brief critical review of available interpretations of liquid fragility, our probabilistic approach is introduced and validated by comparing reported fragility data with the material parameters extracted from reported structural relaxation times, namely, the thermodynamic cooperativity Nc T and the enthalpy Em and entropy Sm of activated molecular migration available for 26 glassformers. Quantitatively, the relevance of Nc T together with Sm and Em as a measure of liquid fragility is verified in principle, and hence our probabilistic interpretation of liquid fragility is supported. © 2014 Elsevier B.V. All rights reserved.

Yuan B.-C.,Beijing Normal University | Yue D.-X.,Lanzhou University
Pedosphere | Year: 2012

Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine (Pinus tabulaeformis) plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling region in the middle of Loess Plateau, China. The results indicated that plantation age and season affected soil microbial and enzymatic parameters significantly. Soil organic C, total N, microbial biomass C, microbial quotient, basal respiration, dehydrogenase, N-α-benzoyl-L-argininamide (BAA)-protease, urease and β-glucosidase increased quickly and tended to be highest at PF21 (21-year plantation), thereafter they remained nearly at a constant level, whereas the metabolic quotient (qCO 2) showed an initial increase and then decreased gradually. Measures of these soil properties showed significant seasonal fluctuations except for organic C and total N, which were found to be relatively stable throughout the study period, and the seasonal distributions were autumn > spring > summer > winter for microbial biomass C, microbial quotient, dehydrogenase, and β-glucosidase; autumn > summer > spring > winter for BAA-protease and urease; and summer > autumn > spring > winter for basal respiration and qCO 2. Significant season × age interaction was observed for biomass C, basal respiration, dehydrogenase and BAA-protease. © 2012 Soil Science Society of China.

Sun H.,Harbin Institute of Technology | Yang C.,Harbin Institute of Technology | Lin R.,Harbin Institute of Technology | Xia W.,Harbin Institute of Technology | Xia W.,Lanzhou University
Advanced Synthesis and Catalysis | Year: 2014

A mild and efficient procedure was developed for the regioselective ring-opening nucleophilic addition reactions of aziridines via visible light photoredox catalysis, that provides a practical synthetic access to 1,2-bifunctional compounds. Furthermore, the regioselective synthesis of non-racemic amino ethers from chiral aziridine could also be achieved under mild conditions. Finally, a possible reaction mechanism was proposed and further supported by control experiments. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

Song Z.,University of Sichuan | Song Z.,Lanzhou University | Kui L.,University of Sichuan | Sun X.,University of Sichuan | Li L.,University of Sichuan
Organic Letters | Year: 2011

A highly stereoselective approach to novel tetrasubstituted (Z)-β-hydroxy-α-TMS silyl enol ethers is described. The reaction proceeds via a sequential addition/[1,2]-Brook rearrangement/epoxide-opening process of TMS-substituted oxiranyl anions with acylsilanes. © 2011 American Chemical Society.

Wang X.,Japan International Center for Materials Nanoarchitectonics | Tian W.,Japan International Center for Materials Nanoarchitectonics | Liu D.,Japan International Center for Materials Nanoarchitectonics | Liu D.,Lanzhou University | And 3 more authors.
Nano Energy | Year: 2013

Nowadays, 2D nanosheets or nanoplatelets have attracted great attention due to their wide applications. However, the synthesis of 2D α-Fe2O3 nanosheets with well-defined hexagonal shape is extremely challenging, because the selective growth along one specific facet is very hard to be realized. In our work, we studied the non-capping ligand mediated reaction within graphene layer chamber, and successfully synthesized α-Fe2O3 hexagonal nanoplatelets sandwiched between graphene layers (HP-Fe-G). These materials exhibit an improved electrochemical performance compared with the pre-existing α-Fe2O3 nanoparticles loaded graphene (G-Fe2O3) composites because of the uniqueness of such architectures: thin nanoplatelets, large enough sandwiched spaces to buffer the volume expansion and N-doped graphene. HP-Fe-G delivered an ultrahigh reversible capacity of 1100mAh/g after 50 cycles, thus higher than their theoretical value (926mAh/g); while G-Fe2O3 composites showed relatively low capacity retention even after only 20 cycles (582mAh/g). In addition, HP-Fe-G also reveal superior rate capability, 887mAh/g at 1C; in comparison, this value was only 135mAh/g at 1C for G-Fe2O3. © 2012 Elsevier Ltd.

Wang W.-Z.,Tianshui Normal University | Wei X.-P.,Lanzhou University
Computational Materials Science | Year: 2011

Based on the first-principle calculations within density functional theory of electronic structure, we propose that the CuHg2Ti-type intermetallic ternary compound Mn2ZnCa is strong candidate for half-metallic (HM) antiferromagnet (AFM), the HM-AFM nature in Mn 2ZnCa originates from d-d orbital hybridization. We also find that the Fermi level just locates in the gap of spin-down states, and the HM properties of Mn2ZnCa is kept within the wide range of 5.91 and 6.60 where exhibit perfect 100% spin polarization of the conduction electrons. Our investigations also indicate the atom coordination surroundings have a great influence on the electron structure. © 2011 Elsevier B.V. All rights reserved.

Yang Y.,CAS Shanghai Institute of Organic Chemistry | Fu X.,CAS Shanghai Institute of Organic Chemistry | Chen J.,CAS Shanghai Institute of Organic Chemistry | Zhai H.,CAS Shanghai Institute of Organic Chemistry | Zhai H.,Lanzhou University
Angewandte Chemie - International Edition | Year: 2012

As easy as ABCD: (-)-Jiadifenin was synthesized in eighteen reaction steps from 1-[(E)-(4′-bromo-2′-butenyl)oxy]-4-methoxybenzene. Key features of this synthesis include: 1) Ireland-Claisen rearrangement to produce the two contiguous quaternary centers at C5 and C6 simultaneously, 2) intramolecular Pauson-Khand reaction (IMPKR) to concurrently construct the A and B rings, and 3) [2+2] photo-cycloaddition to generate the all-carbon quaternary center at C9. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li W.,Sichuan University | Liu X.,Sichuan University | Hao X.,Sichuan University | Cai Y.,Sichuan University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2012

Asymmetric expansion: A catalytic asymmetric ring-expansion reaction of the title compounds occurs in the presence of a Sc(OTf)3 catalyst bearing an N,N?-dioxide-based ligand. Highly functionalized 2-quinolone derivatives containing a chiral C4-quaternary stereocenter were obtained in high yields and high levels of selectivity under mild reaction conditions (see scheme; Tf=trifluoromethanesulfonyl).

Sang P.,Zhejiang University | Yu M.,Zhejiang University | Tu H.,Zhejiang University | Zou J.,Zhejiang University | And 2 more authors.
Chemical Communications | Year: 2013

A highly efficient protocol of copper catalysis for the one-pot synthesis of fused dibenzo[b,f][1,4]oxazepines is reported. The transformation involves a Smiles rearrangement, leading to the completely different regioselectivity from the classical cross-coupling. The easy reaction of aryl chlorides as substrates enhances the practical application of the methodology. © 2013 The Royal Society of Chemistry.

Fang X.,Lanzhou University
Advanced Materials Research | Year: 2012

The particle swarm optimization (PSO)-based approach to resolve the resource-constrained project scheduling problem with the objective of minimizing project duration is introduced in this paper. Computational analyses are provided so as to investigate the performance of the PSO-based approach for the resource-constrained project scheduling problem. The results shows that it is feasible to apply PSO to construction schedule optimization. © (2012) Trans Tech Publications.

Lin C.,Zhejiang University | Li D.,Zhejiang University | Wang B.,Zhejiang University | Yao J.,Zhejiang University | And 2 more authors.
Organic Letters | Year: 2015

The direct thiolation of arenes and alkenes with diaryl disulfides was developed by nickel catalysis. The reaction displayed exceptional compatibility with a wide range of functional groups to regioselectively give the diaryl sulfides and alkenyl sulfides in high yields. © 2015 American Chemical Society.

Liu J.,Harbin Institute of Technology | Zhou X.,Lanzhou University
Journal of Constructional Steel Research | Year: 2010

This paper presents an experimental and analytical study on the behavior of axially compressed tubed RC stub columns. Forty specimens including twenty circular tubed RC (STRC) and twenty square tubed RC (STRC) stub columns were tested to investigate the failure mode and axial load strength of tubed RC columns subjected to axial compression. The effect of diameter/width to thickness ratio of the tubes and compressive strength of concrete were also studied. The effect of height to diameter/width ratio of the separated tube in tubed RC columns was studied to investigate the effect of bond and friction between tube and concrete on the behavior of tubed RC columns. Elastic-plastic analysis on the steel tube was employed to study the mechanism of tubed RC stub columns subjected to axial compression. Equations for the prediction of the ultimate axial load strength of tubed RC stub columns were proposed and the results from prediction were compared with the test results. © 2009 Elsevier Ltd. All rights reserved.

Zhou X.,Lanzhou University | Liu J.,Harbin Institute of Technology
Journal of Constructional Steel Research | Year: 2010

Reinforced concrete (RC) short columns are vulnerable to brittle shear failure during an earthquake. The objective of this research is to evaluate the performance enhancement of RC short columns tubed with circular or square tubes. Eight short columns were tested under combined constant axial load and cyclic lateral load. The tested specimens included three circular tubed RC (CTRC) columns and three square tubed RC (STRC) columns. Two common RC short columns including one circular RC column and one square RC column were also tested as control specimens. The test results indicated that common RC short columns suffered brittle shear failure with little ductility, while the ductility of tubed RC short columns was excellent due to the effective confinement of the outer thin tube to the core concrete. The lateral load strength of CTRC short columns increases with the increasing of axial load ratio, while the axial load ratio has little effect on the plastic deformation capacity of CTRC short columns. The shear strength increases with increasing of axial load ratio, while the plastic deformation capacity decreases with increasing of axial load ratio for STRC short columns. A circular tube prevents the core concrete from shear failure more effectively than a square tube for the tubed RC short columns. A modified ACI design method is adopted to calculate the nominal shear strength of STRC columns as well as CTRC columns based on the test and analysis results. © 2009 Elsevier Ltd. All rights reserved.

Liu Z.,Soochow University of China | Zhang J.,Soochow University of China | Chen S.,Soochow University of China | Shi E.,Soochow University of China | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2012

A radical solution: A Bu 4NI/tert-butyl hydroperoxide (TBHP) catalyzed synthesis of amides through a cross-coupling reaction between acyl and aminyl radicals is described. This method involves the combination of aldehyde C-H bond functionalization and decarbonylation of N,N-disubstituted formamides (see scheme). The cross-coupling is metal-free, has a wide substrate scope, operational simplicity, and gives high yields on scale-up. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen J.,CAS Shanghai Institute of Organic Chemistry | Gao P.,CAS Shanghai Institute of Organic Chemistry | Yu F.,CAS Shanghai Institute of Organic Chemistry | Yang Y.,CAS Shanghai Institute of Organic Chemistry | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2012

An efficient total synthesis of (±)-merrilactoneA has been accomplished, featuring: 1)a Johnson-Claisen rearrangement and the subsequent deprotection-lactonization to generate the Aring, 2)an intramolecular hetero-Pauson-Khand reaction to construct the B and Drings, and 3)a vinylogous Mukaiyama-Michael reaction and reductive carbonyl-alkene coupling to assemble the Cring. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Huang Y.-M.,Lanzhou University
Journal of Engineering Mathematics | Year: 2015

Preconditioners are often applied in various Krylov subspace iteration methods to improve their computing efficiency. In this paper, we consider solving linear systems with a non-Hermitian positive definite coefficient matrix using preconditioned Krylov subspace iteration methods such as the generalized minimal residual (GMRES) method. An $$m$$m-step polynomial preconditioner is designed based on the Hermitian and skew-Hermitian splitting (HSS) iteration method proposed by Bai et al. (SIAM J Matrix Anal Appl 24:603–626, 2003). The proposed preconditioned system is solved by fully utilizing the HSS iteration method. Theoretical and experimental results show that the proposed $$m$$m-step preconditioner is efficient in accelerating GMRES for solving a non-Hermitian positive definite linear system. © 2013, Springer Science+Business Media Dordrecht.

Wang L.,Lanzhou University
Journal of Physics Condensed Matter | Year: 2012

A comprehensive examination of the kinetic liquid model (Wang etal 2010 J. Phys.: Condens. Matter 22 455104) is carried out by fitting the structural relaxation time of 26 different glass-forming liquids in a wide temperature range, including most of the well-studied materials. Careful analysis of the compiled reported data reveals that experimental inaccuracies should not be overlooked in any benchmark test of relating theories or models (e.g.in Lunkenheimer etal 2010 Phys. Rev. E 81 051504). The procedure, accuracy, ability, and efficiency of the kinetic liquid model are discussed in detail and in comparison with other available fitting methods. In general, the kinetic liquid model could be verified by 17 of the 26 compiled data sets and can serve as a meaningful approximative method for analyzing these liquids. Nonetheless, further experimental examinations in a wide temperature range are needed and are called for. Through fitting, the microscopic details of these liquids are extracted, namely, the enthalpy, entropy, and cooperativity in structural relaxation, which may facilitate further quantitative analysis to both the liquidus and glassy states of these materials. © 2012 IOP Publishing Ltd.

Jia M.F.,Lanzhou University
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology | Year: 2012

The aim of this study was to investigate the relationship of the gene polymorphisms of myeloperoxidase (MPO) and NAD (P) H: quinone oxidoreductase 1 (NQO1) with the susceptibility to acute leukemia (AL) in Chinese Gansu population. A 1:1 paired case-control study of 150 patients with acute leukemia and 150 cancer-free inpatients as a control was conducted to detect the polymorphisms of MPO and NQO1 by LDR techniques. The results showed that the MPO-463A genotype frequency in patient group was lower than that in control group, and there was significant difference of MPO (G-463A) genotype between patient group and control group (χ(2) = 11.828, P < 0.05, OR = 0.368, 95%CI = 0.205 - 0.610). The NQO1-609T genotype frequency in patient group was higher than that in control group, and there was significant difference of NQO1 (C-609T) genotype between patient group and control group (χ(2) = 17.931, P < 0.05, OR = 1.428, 95%CI = 1.237 - 3.339). The combined gene analysis showed that the AML risk in patients carrying the wild genotypes of MPO and NQO1 was dropped to 33.6%. It is concluded that the MPO and NQO1 gene polymorphisms are associated with susceptibility to AL. The AL risk may decrease in patients carrying MPO (G-463A) mutant gene (GA/AA), while the AL risk may increase in patients carrying NQO1 (C-609T) mutant gene (TC/TT). The combined effect of MPO and NQO1 wild genotypes may further decrease AL risk.

Qiu Q.-S.,University of Illinois at Urbana - Champaign | Qiu Q.-S.,Lanzhou University | Fratti R.A.,University of Illinois at Urbana - Champaign
Journal of Cell Science | Year: 2010

Nhx1p is a Na+(K+)/H+ antiporter localized at the vacuolar membrane of the yeast Saccharomyces cerevisiae. Nhx1p regulates the acidification of cytosol and vacuole lumen, and is involved in membrane traffic from late endosomes to the vacuole. Deletion of the gene leads to aberrant vacuolar morphology and defective vacuolar protein sorting. These phenotypes are hallmarks of malfunctioning vacuole homeostasis and indicate that membrane fusion is probably altered. Here, we investigated the role of Nhx1p in the regulation of homotypic vacuole fusion. Vacuoles isolated from nhx1Δ yeast showed attenuated fusion. Assays configured to differentiate between the first round of fusion and ongoing rounds showed that nhx1Δ vacuoles were only defective in the first round of fusion, suggesting that Nhx1p regulates an early step in the pathway. Although fusion was impaired on nhx1Δ vacuoles, SNARE complex formation was indistinguishable from wild-type vacuoles. Fusion could be rescued by adding the soluble SNARE Vam7p. However, Vam7p only activated the first round of nhx1Δ vacuole fusion. Once fusion was initiated, nhx1Δ vacuoles appeared behave in a wild-type manner. Complementation studies showed that ion transport function was required for Nhx1p-mediated support of fusion. In addition, the weak base chloroquine restored nhx1Δ fusion to wild-type levels. Together, these data indicate that Nhx1p regulates the initiation of fusion by controlling vacuole lumen pH.

Qiu Q.-S.,Lanzhou University
Plant Signaling and Behavior | Year: 2016

The Arabidopsis NHX antiporter family contains eight members that are divided into three subclasses: vacuolar, endosomal, and plasma membrane. While the plasma membrane and vacuolar NHXs have been studied extensively, the activity and function of the endosomal NHXs are beginning to be discovered. AtNHX5 and AtNHX6 are endosomal Na+,K+/H+ antiporters that share high sequence similarity. They are localized in the Golgi, trans-Golgi network (TGN), and prevacuolear compartment (PVC). Studies have shown that AtNHX5 and AtNHX6 mediate K+ and Na+ transport, and regulate cellular pH homeostasis. Sequence alignment has found that AtNHX5 and AtNHX6 contain four conserved acidic amino acid residues in transmembrane domains that align with yeast and human NHXs. Three of these conserved acidic residues are critical for K+ transport and seedling growth in Arabidopsis. Moreover, studies have shown that the precursors of the seed storage proteins are missorted to the apoplast in the nhx5 nhx6 knockout mutant, suggesting that AtNHX5 and AtNHX6 regulate protein transport into the vacuole. Further analysis found that AtNHX5 and AtNHX6 regulated the binding of VSR to its cargoes. Taken together, AtNHX5 and AtNHX6 play an important role in cellular ion and pH homeostasis, and are essential for protein transport into the vacuole. © 2016 Taylor & Francis Group, LLC.

Yang Y.,Zhejiang University | Xie C.,Zhejiang University | Xie Y.,Zhejiang University | Zhang Y.,Zhejiang University | Zhang Y.,Lanzhou University
Organic Letters | Year: 2012

A novel copper-catalyzed annulation of 2-alkylazaarenes with α,β-unsaturated carboxylic acids has been accomplished. This reaction featuring C-H olefination and decarboxylative amination processes provides a concise access to C-2 arylated indolizines from simple and readily available starting materials. © 2012 American Chemical Society.

Xia X.,Peking University | Song S.,Peking University | Niu Y.,Lanzhou University | Niu Y.,Durham University
Chemical Geology | Year: 2012

A tholeiite-boninite terrane occurs as a ~. 4.5-km-thick massif with lavas and intrusions in the Dachadaban (DCDB) area, the middle part of the North Qilian oceanic-type suture zone. It comprises two distinct lithological groups: the lower tholeiite unit and the upper boninite unit. The lower tholeiite unit consists of massive lava flows and subordinate gabbro intrusions with MORB-like characteristics that could represent 5-6% melting of an enriched MORB mantle. In contrast, the overlying boninite unit consists of pillow lavas, dolerite dykes and gabbro intrusions and shows high-Ca boninite features that may be formed by continuous melting of the extremely refractory mantle with the aid of a combination of the elevated mantle potential temperature of 1380-1460. °C at depths of 42-66. km and involvement of slab-derived hydrous fluids/melts. Zircon U-Pb SHRIMP dating shows that lower tholeiite magmatism lasted for at least 12. M.y. from 517 Ma to 505 Ma and upper boninite volcanism occurred between 505 and 487 Ma, which is consistent with the earliest age (486 ± 7 Ma) of the SSZ-type ophiolite belt immediately north of the Dachaidaban (DCDB) tholeiite-boninite terrane. The lower tholeiites are considered to represent the products of earliest infant arc magmatism by decompression-induced partial melting of the relatively "dry" and fertile upwelling mantle in response to the onset of subduction. The upper boninite unit with younger age of 487 ± 9 Ma is interpreted as earliest products of infant arc splitting and subsequent back-arc basin development. Therefore, the long-lived DCDB tholeiite-boninite sequence presents a key lithological record of early stages of supra-subduction zone magmatic activity evolved from subduction initiation at ~ 517 Ma to back-arc extension at ~ 487 Ma. © 2011 Elsevier B.V.

Li J.,CAS Institute of Atmospheric Physics | Feng J.,CAS Institute of Atmospheric Physics | Feng J.,Lanzhou University | Li Y.,CSIRO
International Journal of Climatology | Year: 2012

The NCEP/NCAR reanalysis and precipitation data from the Australian Bureau of Meteorology are used to analyse variability in rainfall during the austral summer (December-March, DJFM) in northeast Australia (NEA). NEA rainfall shows a marked decrease over the past 50 years, mainly in the austral summer. Our analysis reveals that the summer rainfall decrease in NEA is generally an interdecadal phenomenon. The declining trend has an imprint in the tropical Australian summer monsoon (TASM). Not only does TASM have a phase-to-phase influence on NEA summer rainfall at the interannual scale, it is also closely linked with interdecadal variation in NEA summer rainfall. Thus, the decrease in NEA at the interdecadal scale could be attributed to corresponding variation in TASM. Moreover, the coupled linkage between TASM and NEA summer rainfall appears to be largely independent of El Niño-Southern Oscillation. One possible reason for the interdecadal weakening trend in TASM is a sustained interdecadal warming trend in sea surface temperature (SST) over the Wharton Basin (100°-130°E, 20°-5°S). When the Wharton Basin is in a cold state, anomalous westerlies occur in the lower troposphere in the TASM region, and cyclonic circulation anomalies and rising flows occur in the low and middle troposphere over NEA, which are associated with a strong TASM situation, consequently favouring enhanced rainfall over NEA; the opposite occurs in the case of a warm Wharton Basin. SST over the Wharton Basin has shown a continuous warming trend over the past 60 years, contributing to the weakening of TASM and, consequently, a decrease in NEA summer rainfall. © 2011 Royal Meteorological Society.

Tian Y.,Lanzhou University | Tian Y.,CAS Institute of Semiconductors | Zhang L.,CAS Institute of Semiconductors | Ding J.,CAS Institute of Semiconductors | Yang L.,CAS Institute of Semiconductors
Optics Express | Year: 2014

We report a silicon photonic integrated circuit which can perform the operation of half-adder based on two cascaded microring resonators (MRRs). PIN diodes embedded around MRRs are employed to achieve the carrier injection modulation. Two electrical pulse sequences representing the two operands of the half-add operation are applied to PIN diodes to modulate two MRRs through the plasma dispersion effect. The final operation results of bitwise Sum and Carry operation are output at two different output ports of the device. Microheaters fabricated on the top of MRRs are employed to compensate two MRRs resonance mismatch caused by the fabrication error through the thermo-optic effect. Addition operation of two bits with the operation speed of 100Mbps is demonstrated. © 2014 Optical Society of America.

Bing W.,Lanzhou University
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao | Year: 2016

With the continuous development of science and technology and the wide application of multimedia technology, the multimedia system based on the computer platform is gradually introduced into the field of education. In the process of basketball training and teaching, the application of computer multimedia system makes the teaching process more rich and innovative, has achieved good practical results. This paper mainly introduces the combination the multimedia system based on the computer platform and training process of basketball tactics, and introduces the related method with introducing the actual effect of the system. The application of multimedia system in the training of basketball tactics can carry out the teaching of tactics better, to cultivate students' tactics consciousness, and vail the development of the cause of basketball education, and to provide a reference for other sports education and training, let physical education to be enough to play a more significant efficiency.

Xiang Jiang W.,Nanjing Southeast University | Yang Luo C.,Nanjing Southeast University | Lei Mei Z.,Lanzhou University | Jun Cui T.,Nanjing Southeast University
Applied Physics Letters | Year: 2013

We propose and experimentally demonstrate an ultrathin but nearly perfect dc electric invisibility cloak. In the dc limit, transformation optics reduces to transformation electrostatics. Based on a special coordinate transformation, we derive a nearly perfect dc electric cloak which is composed of homogeneous and anisotropic conducting material. Due to the homogeneity feature, the dc cloak is realized using an ultrathin dc metamaterial with only one-unit-cell thickness, which is the ultra limit for practical artificial materials. Although ultrathin, our experimental results show that the dc cloak has excellent performance with nearly perfect cloaking behaviour. © 2013 American Institute of Physics.

Liu Z.,Anhui University of Science and Technology | Fan G.-P.,Anhui University of Science and Technology | Wang G.-W.,Anhui University of Science and Technology | Wang G.-W.,Lanzhou University
Chemical Communications | Year: 2012

The solvent-free reactions of β-enamino carbonyl compounds with 1-(pyridin-2-yl)-enones in the presence of manganese(iii) acetate dihydrate unexpectedly afforded 2-acyl-3-aryl-6,7-dihydro-4(5H)-benzofuran derivatives under mechanical milling conditions. © 2012 The Royal Society of Chemistry.

Zhao X.-L.,University of Electronic Science and Technology of China | Wang F.,Lanzhou University | Huang T.-Z.,University of Electronic Science and Technology of China | Ng M.K.,Hong Kong Baptist University | Plemmons R.J.,Wake forest University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2013

The main aim of this paper is to study total variation (TV) regularization in deblurring and sparse unmixing of hyperspectral images. In the model, we also incorporate blurring operators for dealing with blurring effects, particularly blurring operators for hyperspectral imaging whose point spread functions are generally system dependent and formed from axial optical aberrations in the acquisition system. An alternating direction method is developed to solve the resulting optimization problem efficiently. According to the structure of the TV regularization and sparse unmixing in the model, the convergence of the alternating direction method can be guaranteed. Experimental results are reported to demonstrate the effectiveness of the TV and sparsity model and the efficiency of the proposed numerical scheme, and the method is compared to the recent Sparse Unmixing via variable Splitting Augmented Lagrangian and TV method by Iordache © 1980-2012 IEEE.

To evaluate the protection of penehyclidine hydrochloric postconditioning on HIF-1α (hypoxia-inducible factor-1α) in renal tissue injury induced by lower limb ischemia/reperfusion (I/R). A total of 72 adult male Wistar rats weighing 230 - 250 g were randomly divided into 3 groups: control (group C), limb ischemia-reperfusion (group R/I) and penehyclidine hydrochloride postconditioning (group P). The animals were anesthetized by inhaling 2% isoflurane and blood flow of bilateral lower limbs was blocked with rubber bands for 3 h in groups P and R/I. In group P, penehyclidine hydrochloride 0.15 mg/kg was injected via caudal vein at 3 min pre-reperfusion. After sacrificing, their kidneys were removed at 3 h of ischemia and 1, 3, 6 h of reperfusion respectively. The blood urea nitrogen (BUN) and creatinine (Cr) were detected by colorimetric method, plasma tumor necrosis factor-α (TNF-α) by ELISA (enzyme-linked immunosorbent assay) and HIF-1α of renal tissue by immunohistochemistry. Renal pathological changes were observed under light microscope. Compared with group C, the serum levels of BUN and Cr increased while TNF-α and HIF-1α were up-regulated in groups I/R and P (P < 0.05). As compared with group I/R, the serum levels of BUN, Cr and MDA decreased while TNF-α and HIF-1α were down-regulated in group P. [at T2: (15.10 ± 1.88) mmol/L vs (19.46 ± 2.76) mmol/L, (113 ± 10) μmol/L vs (143 ± 11) μmol/L, (13.8 ± 1.7) nmol/g vs (15.5 ± 1.8) nmol/g, (53.1 ± 3.1) ng/L vs (53.9 ± 4.8) ng/L, 0.298 ± 0.015 vs 0.471 ± 0.032, all P < 0.05]. Penehyclidine hydrochloride can down-regulate the expression of HIF-1α and attenuate the renal injury induced by lower limb I/R. And the mechanisms may be through inhibiting the inflammatory reactions, reducing the release of oxygen free radicals and improving the conditions of hypoxia and ischemia.

Mao X.R.,Lanzhou University
Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences | Year: 2011

To design and synthesize small interfering RNA (siRNA) targeting connective tissue growth factor (CTGF) and to investigate its effect on liver fibrosis. The interference sequence of CTGF was designed and synthesized. Rat hepatic fibrosis model was induced by intraperitoneal injection of 40 % CCl4(3 ml/kg). Thirty male rats were randomly divided into 5 groups: in normal control and model groups rats received tail vein injection of normal saline every 3 days for 8 consecutive weeks; in preventive group rats received tail vein injection of CTGF siRNA (0.1 mg/kg) every 3 days for 8 weeks; in 2-w treatment group CTGF siRNA was given for 6 weeks starting from two weeks after CCl4 injection; in 4-w treatment group CTGF siRNA was given for 4 weeks starting 4 weeks after CCl4 injection. The serum and hepatic tissue samples were harvested 3 days after the last CCl4 injection. Hepatic fibrosis indices were measured. Expression of CTGF mRNA and protein in the liver was evaluated by RT-PCR and Western blot, respectively. Fibrosis in rat liver was analyzed by Masson staining. Compared with model group (0.544 0.019), the expression of CTGF mRNA and protein in liver of both preventive(0.105 ± 0.003) and 2-w treatment groups (0.190 ± 0.006) were markedly down-regulated (P<0.05). Inflammation, necrosis and fibrosis in hepatic tissue were significantly attenuated. In addition, the serum ration of liver fibrosis indices was greatly reduced(P<0.05). Compared with preventive and 2-w treatment groups, the expression of CTGF mRNA and protein in liver in 4 weeks of treatment group were up-regulated (P<0.05); inflammation, necrosis and fibrosis in hepatic tissue were relative increased; and the serum concentrations of liver fibrosis indices were relatively higher (P<0.05). The highly effective CTGF siRNA has been successfully synthesized, which can inhibit CTGF expression in liver, prevent hepatic fibrosis and its progress in rats.

Cao L.Y.,Lanzhou University
Zhongguo gu shang = China journal of orthopaedics and traumatology | Year: 2012

To evaluate the clinical effectiveness of pulsed electromagnetic field therapy in the treatment of knee osteoarthritis. Based on the principles and methods of Cochrane systematic reviews, the authors searched the Cochrane Library (2012, 2 issue), PubMed (1966 to February, 2012), EMBASE (1974 to February, 2012), Chinese Biomedicine Database (1978 to February, 2012), China Journal Full-text Database (1979 to February, 2012), VIP database (1989 to February, 2012), as well as search engine Google Scholar. Randomized controlled trials (RCTs) of pulsed electromagnetic field therapy to treat knee osteoarthritis were included. The authors assessed the quality of the included trials according to the Cochrane Handbook for Systematic Reviews of Interventions Version. The Cochrane Collaboration's software RevMan 5.1 was used for meta-analysis. Five RCTs totaling 331 patients were included. The results showed that compared with placebo control treatment, pulsed electromagnetic field therapy had little clinical benefit in relieving the pain of knee osteoarthritis [WMD=0.12, 95%CI (-0.46,0.69)], reducing morning stiffness time [WMD=0.08, 95%CI (-0.05, 0.21)] and improving the knee function [WMD=-1.16, 95%CI (-4.36, 2.05)]. There were no significant differences between the two groups. The effects of Pulsed electromagnetic field therapy for treating knee osteoarthritis need more powerful trails to be confirmed. The above conclusions still need more high-quality randomized controlled trails to be verified owing to the limitations of the number and the quality of systematic review included studies.

Zhang H.,University of the Humanities | Shaheen S.A.,University of California at Berkeley | Chen X.,Lanzhou University
International Journal of Sustainable Transportation | Year: 2014

This article examines four phases in bicycle evolution in China from initial entry and slow growth (1900s to 1978), to rapid growth (1978 to 1995), bicycle use reduction (1995 to 2002), and policy diversification (2002 to present). Two bicycle innovations, electric bikes, and public bikesharing (the shared use of a bicycle fleet), are also explored in this article. Electric bikes could provide a transitional mode on the pathway to bicycle and public transportation integration or to small battery electric cars. Four lessons have been learned from China's electric bike experience relevant to government policy and management. Public bikesharing represents an important step towards integrating the bicycle with bus, metro, and rail systems. Five early operational lessons have been identified from China's limited public bikesharing experience. © 2014 Copyright Taylor and Francis Group, LLC.

PtAu bimetallic nanoparticles (NPs) were successfully synthesized on graphene sheets-multi walled carbon nanotubes (G-CNTs) hybrid nanomaterials via a simple one-step chemical co-reduction method in ethylene glycol (EG)-water system. The nanocomposites (PtAu/G-CNTs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Then a sensitive nonenzymatic hydrogen peroxide (H2O2) sensor was fabricated based on PtAu/G-CNTs nanocomposites modified glassy carbon electrode (GCE). The results of electrochemical experiments demonstrated that the sensor exhibited excellent electrocatalytic activity to the reduction of H2O2. The sensor displayed a fast amperometric response time of less than 4s with linear detection range from 2.0 to 8561 μM and a relatively low detection limit of 0.6 μM (S/N=3). In addition, the sensor also showed good selectivity for H2O2 detection, long-term stability and reproducibility. Copyright © 2013 Elsevier B.V. All rights reserved.

Cui R.,Lanzhou University
Journal of Convergence Information Technology | Year: 2011

The aim of this paper is to investigate the problem of the *-ideal retraction of some special abundant semigroups. In order to get a characterization for an abundant semigroup satisfying the regularity condition to have the *-ideal property, we first give the definition of the *-ideal retraction property and consider in the condition of a semigroup S with a zero element 0 such that each *- ideal of S has a dual, S has the *-retraction property. Based on the regularity condition and idempotent method, we give a necessary and sufficient condition for an abundant semigroup satisfying the regularity condition to have the *-ideal property. Finally, an example is given to establish a characterizations of adequate semigroups satisfying the regularity condition with the *-ideal retraction property.

Let G be a plane bipartite graph and M(G) the set of perfect matchings of G. A property that the Z-transformation digraph of perfect matchings of G is acyclic implies a partially ordered relation on M(G). It was shown that M(G) is a distributive lattice if G is (weakly) elementary. Based on the unit decomposition of alternating cycle systems, in this article we show that the poset M(G) is direct sum of finite distributive lattices if G is non-weakly elementary; Further, if G is elementary, then the height of distributive lattice M(G) equals the diameter of Z-transformation graph, and both quantities have a sharp upper bound, where n denotes the number of inner faces of G. © 2010 Springer Science+Business Media B.V.

Yang F.,Lanzhou University of Technology | Fu C.-L.,Lanzhou University
Computers and Mathematics with Applications | Year: 2010

This paper investigates the inverse problem of determining a heat source using a parabolic equation where data are given at some fixed location. The problem is ill-posed, i.e., the solution (if it exists) does not depend continuously on the data. A simplified Tikhonov regularization method is given and an order optimal stability estimate is obtained. A numerical example shows that the regularization method is effective and stable. © 2010 Elsevier Ltd. All rights reserved.

Bai Y.,University of Michigan | Bai Y.,Lanzhou University | Ho S.,University of Michigan | Kotov N.A.,University of Michigan
Nanoscale | Year: 2012

Application of nanocomposites in MEMS, flexible electronics, and biomedical devices is likely to demonstrate new performance standards and resolve a number of difficult technical problems enabled by the unique combinations of electrical, optical, and mechanical properties. This study explores the possibility of making microscale nanocomposite patterns using the fusion of two highly versatile techniques: direct-write maskless UV patterning and layer-by-layer assembly (LBL). Together they can be applied to the production of a wide variety of nanostructured coatings with complex patterns. Single-walled carbon nanotube (SWNT) and gold nanoparticle LBL nanocomposites assembled with chitosan (CH) were made into prototypical patterns such as concentric helices and bus-line-and-stimulation-pads (BLASPs) used in flexible antennas and neuroprosthetic devices. The spatial resolution of the technique was established with the standard line grids to be at least 1 μm. Gold nanoparticle films revealed better accuracy and higher resolution in direct-write patterning than SWNT composites, possibly due to the granular rather than fibrous nature of the composites. The conductivity of the patterned composites was 6.45 × 10 -5 Ω m and 3.80 × 10 -6 Ω m at 20°C for nanotube and nanoparticle composites, respectively; in both cases it exceeds electrical parameters of similar composites. Fundamental and technological prospects of nanocomposite MEMS devices in different areas including implantable biomedical, sensing, and optical devices are discussed. This journal is © 2012 The Royal Society of Chemistry.

Yun X.D.,Lanzhou University
Zhongguo gu shang = China journal of orthopaedics and traumatology | Year: 2012

To evaluate the middle term effectiveness of medial patellofemoral ligament (MPFL) reconstruction for the treatment of recurrent patellar dislocation. From February 2007 to January 2010, 65 patients including 6 males and 59 females with recurrent patellar dislocation received the MPFL reconstruction. The reconstruction was performed using ipsilateral semitendinosis tendon to restore the damaged MPFL. Patients were evaluated pre-operatively and post-operatively by physical and subjectively with the IKDC (International Knee Documentation Committee), Tegner, and Lysholm questionnaires and radiographic examination. The average follow-up duration was 20 months (ranged, 15 to 23 months). No recurrent episodes of dislocation or subluxation occurred. A firm endpoint to lateral patellar translation was noted in all patients at most recent follow-up. The Lysholm subjective knee evaluation score improved from (60.6 +/- 3.7) preoperatively to (89.8 +/- 4.6) postoperatively; and Tegner scores improved from (3.6 +/- 0.4) to (5.6 +/- 0.3), IKDC from (40.0 +/- 3.5) to (82.0 +/- 3.6). Radiographic evaluation demonstrated improvements in the congruence and sulcus femoral angles. MPFL reconstruction is an effective surgical procedure for the treatment of recurrent patellar dislocation.

Zeng X.L.,Lanzhou University
Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases | Year: 2011

To explore the effects of rosiglitazone on peroxisome proliferator activated receptor-γ (PPAR-γ), nuclear factor-κB and tumor necrosis factor-α (TNF-α) in patients with chronic obstructive pulmonary disease (COPD). From Apr. 2010 to Nov. 2010, 30 patients with acute exacerbations of COPD, 22 males and 8 females, age 54 - 87 (mean 72 ± 9) years and 24 healthy controls, 18 males and 6 females, age 52 - 80 (mean 69 ± 10) years were included. The peripheral blood mononuclear cells (PBMCs) were isolated from venous blood and then cultured. On the basis of the treatment given, the PBMCs of COPD patients were divided into 3 groups: non-treatment group, rosiglitazone treatment group (rosiglitazone group) and rosiglitazone and GW9662 treatment group (combined treatment group). Cells from the healthy controls (control group) did not receive any drug treatment. The mRNA expression of PPAR-γ and NF-κB was measured with real-time PCR. The protein expression and nuclear translocation of PPAR-γ and NF-κB were detected using immunofluorescence with laser scanning confocal microscopy. The TNF-α level in culture supernatant was measured with ELISA. One-way ANOVA and LSD-t test and the Pearson correlation coefficient were used for statistical analysis. The mRNA and protein levels of PPAR-γ were lower in the non-treatment group (0.52 ± 0.10, 55 ± 11) than those in the control group (1, 85 ± 9), while the levels of NF-κB mRNA and protein were higher in the non-treatment group (1.69 ± 0.07, 145 ± 17) than those in the control group (1, 118 ± 7). The mRNA and protein levels of PPAR-γ in the rosiglitazone group (4.47 ± 0.11, 204 ± 12) were significantly increased compared with the non-treatment group, while the mRNA and protein levels of NF-κB (0.33 ± 0.04, 59 ± 14) were remarkably decreased compared with the non-treatment group. The mRNA and protein levels of PPAR-γ (2.25 ± 0.31, 142 ± 23) were significantly decreased in the combined treatment group compared to the rosiglitazone group, but higher compared with the non-treatment group, while the mRNA and protein levels of NF-κB (0.64 ± 0.02, 90 ± 10) were increased compared with the rosiglitazone group, but decreased compared to the non-treatment group (F = 29.21 - 567.42, all P < 0.01). The TNF-α level was significantly higher in the non-treatment group (96.2 ± 1.4) μg/L than that in the control group (85.3 ± 1.0) μg/L. The TNF-α level in the rosiglitazone group (63.0 ± 2.5) μg/L was remarkably decreased compared with the non-treatment group, while that in the combined treatment group (83.3 ± 1.9) μg/L was increased compared with the rosiglitazone group, but decreased compared to the non-treatment group (F = 293.72, P < 0.01). The proteins of PPAR-γ and NF-κB were respectively located in cytoplasm and in nucleus in the non-treatment group, meanwhile they were located in both cytoplasm and nucleus in the control group. PPAR-γ protein was translocated from cytoplasm into nucleus and NF-κB protein was translocated from nucleus into cytoplasm in the rosiglitazone group. In the combined treatment group, PPAR-γ protein translocated from nucleus into cytoplasm and NF-κB protein partly translocated from cytoplasm into nucleus. By linear correlation analysis, PPAR-γ protein was negatively correlated with NF-κB protein and TNF-α level (r = -0.935, -0.924, all P < 0.01), while NF-κB protein was positively correlated to TNF-α level (r = 0.846, P < 0.01). The expression and activity of PPAR-γ were decreased in COPD patients. PPAR-γ agonist rosiglitazone inhibited inflammation in COPD through upregulating the expression and activity of PPAR-γ and inhibition of NF-κB and TNF-α. It suggests that PPAR-γ may play an important role in the inflammation of COPD.

Luo J.J.,Lanzhou University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2012

To study the chemical constituents from the flower Juglans regia. All compounds were isolated and purified by normal column chromatograph and polyamide chromatograph, the chemical strucures were mainly elucidated by ESI-MS and NMR spectra. Seven compounds were identified as follows: 4,5,8-trihydroxy-alpha-tetralone 5-O-beta-D-glucopyranoside(1),4,5-dihydroxy-alpha-tetralone4-O-beta-D-glucopyranoside(2), 5-hydroxy-4-methoxytetralone (3), 5-hydroxy-1, 4-naphthoquinone (4), rutin (5), vanillin (6), tetracosanoic acid 2,3-dihydroxypropyl ester (7). All compounds are isolated from this plant for the first time.

Zhou D.,Lanzhou University
Nan fang yi ke da xue xue bao = Journal of Southern Medical University | Year: 2011

To investigate the expression of Csk-binding protein (CBP) in esophageal carcinoma and its association with the tumorigenesis and progression of esophageal cancer. RT-PCR and Western blotting were employed to determine the expressions of CBP at the mRNA and protein levels in 50 pairs of fresh esophageal carcinoma tissue and the adjacent normal tissues. CBP mRNA and protein expressions in normal tissues were 1.43- and 1.28-fold higher than those in the cancer tissues, respectively (P<0.05). The expressions of CBP mRNA and protein were positively correlated (P=0.015). The decreased expressions of CBP were significantly correlated to lymph node metastasis of esophageal cancer (P<0.05). The expression of CBP gene is decreased in esophageal carcinoma, which might contribute to the tumorigenesis and progression of this malignancy.

Huang J.,Lanzhou University
Zhonghua nei ke za zhi [Chinese journal of internal medicine] | Year: 2011

To explore the relationship between coagulation/anticoagulation imbalance and oxidative stress in the patients with chronic obstructive pulmonary disease during acute exacerbation (AECOPD) before and after treatment. Plasma tissue factor (TF) and tissue factor pathway inhibitor (TFPI) activity was detected by chromogenic assay in 28 AECOPD patients before and after treatment as well as in 30 healthy controls. The total antioxidative capacity (TAC), malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) in plasma were measured in both groups. The levels of plasma TF and TFPI, and their ratio (TF/TFPI) in AECOPD patients before treatment were significantly higher than those after treatment (all P < 0.01), the latter were still higher than those in the healthy persons (all P < 0.01). The levels of the TAC and GSH-PX in plasma in AECOPD patients before treatment were significantly lower than those after treatment (all P < 0.01), the latter were still lower than those in the healthy persons (all P < 0.01). The plasma MDA in AECOPD patients before treatment was significantly higher than that after treatment (P < 0.01), which was still higher than that in the healthy persons (P < 0.05). There were negative correlations between TF/TFPI ratio and TAC (r = -0.518, P < 0.01), GSH-PX (r = -0.454, P < 0.05), PaO2 (r = -0.511, P < 0.01) respectively and a positive correlation between TF/TFPI ratio and the percentage of neutrophils (r = 0.379, P < 0.05) in AECOPD patients before treatment. There still were negative correlations between TF/TFPI ratio and TAC (r = -0.420, P < 0.05), FEV(1)% to predicted (r = -0.480, P < 0.05) respectively, and a positive correlation between TF/TFPI ratio and MDA (r = 0.451, P < 0.05) in AECOPD patients after treatment. There existed coagulation/anticoagulation imbalance and oxidation/antioxidation imbalance before and after treatment in AECOPD patients and their relationship was explored.

Yong H.,Key Laboratory of Mechanics on Western Disaster and Environment | Liu F.,Key Laboratory of Mechanics on Western Disaster and Environment | Zhou Y.,Lanzhou University
Applied Physics Letters | Year: 2010

The objective of this paper is to obtain the analytical solutions which satisfy the differential Ginzburg-Landau equations and some boundary conditions. Based on the linear deformation theory, the effects of prestrain on the wave function and magnetic potential of deformable superconductors have been investigated in the presence of a weak magnetic field. The results show that for the superconductors with a linearly elastic deformation, the wave function in the materials should be considered for two different cases, i.e., type I and type II. The prestrain effect in deformable superconductors should not be neglected in determining the superconductivity in superconductors. © 2010 American Institute of Physics.

Liang J.D.,Lanzhou University
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica | Year: 2012

To analyze the relationship between high-performance liquid chromatography (HPLC) fingerprints of the chloroform extract fractions of Peucedanum harrysmithii var. subglabrum (PHS) and its phlegm-reducing effect, in order to establish "active component group for reducing phlegm". HPLC was adopted to determine and analyze HPLC fingerprints of chloroform extract fractions of PHS. Phenol red expectorant experiment was used to observe the phlegm-reducing effect in mice. Mice were administered intragastrically with chloroform extract fractions for 6 days (1.4 g x kg(-1)), with acute bronchitis syrup as the positive control drug (12 mL x kg(-1)). The phenol red secretion in mice was determined by spectrophotometer. Then the grey relational analysis was used to study the spectrum-effect relationship. The phlegm-reducing effect of the chloroform extract fractions of PHS were resulted from the combined effect of all of its chemical components. Its various characteristic peaks represented different chemical components, and the order of their contributions to the phlegm-reducing effect was (number of peaks) 13 > 12 > 16 > 18 > 19 > 6 > 20 > 14 > 1 > 11 > 15 > 10 > 17 > 2 > 5 > 4 > 7 > 3 > 8 > 9, in No. 1, 3, 4, 10, 13 and 16 characteristic peaks were identified as marmesin, psoralen, xanthotoxin, Pd-Ib, pteryxin and peuformosin. The chloroform extract fractions of PHS show strongly phlegm-reducing effect. There may be certain relationship between their HPLC fingerprint and phlegm-reducing effect.

Xu Z.,CAS Beijing National Laboratory for Molecular | Xu Z.,University of Chinese Academy of Sciences | Liao Q.,CAS Beijing National Laboratory for Molecular | Shi Q.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
Advanced Materials | Year: 2012

Low-threshold nanolasers based on slab nanocrystals (SNCs) of highly emissive H-aggregated organic semiconductors are reported. A lasing threshold as low as 100 nJ cm-2 is achieved in a high-quality (cavity quality factor â1000) Fabry-Pérot cavity constituted by the two lateral-faces of SNCs at the wavelength scale. Moreover, the laser light generated in the ultrasmall radial cavity of SNCs can propagate along its length up to hundreds of micrometers, making them attractive building blocks for miniaturized photonic circuits. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luo Y.,Huazhong University of Science and Technology | Li B.,Huazhong University of Science and Technology | Wang W.,Lanzhou University | Wu K.,Huazhong University of Science and Technology | Tan B.,Huazhong University of Science and Technology
Advanced Materials | Year: 2012

Aromatic heterocyclic microporous polymers with high surface areas are obtained by directly crosslinking of the heterocyclic monomers under mild conditions. Owing to the narrow pore system and the heteroatom-rich pore surface, these networks exhibit high CO2 adsorption capacity and selectivity. At 273 K, the CO2/N2 selectivity of Py-1 is about 117, which is among the highest the reported microporous materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang L.,Lanzhou University
Journal of Non-Crystalline Solids | Year: 2014

From our recent studies on crystal melting, a small-liquid-nucleus scenario is concluded. On this basis, a thermodynamic cooperativity is proposed to be the number of atoms in a liquid nucleus, which may serve as an upper limit for the kinetic cooperativity. Preliminary applications of the concept of a thermodynamic cooperativity in elucidating several significant features of glass-forming liquids are promising. In this work, efforts are devoted for a detailed examination of the existence of the suggested thermodynamic cooperativity by exploring a variety of research results on crystal melting, gas condensation, and liquids, specifically, in a logical chain of reasoning, (i) whether vacancies may dominate the high-temperature properties of crystals, (ii) whether liquid nucleation may be initiated from vacancies, and (iii) whether the liquid nucleus may be very small. In addition, successful applications of the concept of a thermodynamic cooperativity are briefly reviewed, lending further supports to its existence. © 2013 Elsevier B.V. All rights reserved.

Li B.,Huazhong University of Science and Technology | Guan Z.,Huazhong University of Science and Technology | Wang W.,Lanzhou University | Yang X.,Huazhong University of Science and Technology | And 3 more authors.
Advanced Materials | Year: 2012

Highly dispersed palladium chloride catalysts locked in triphenylphosphine-functionalized knitting aryl network polymers (KAPs) are developed and exhibit excellent activity under mild conditions in the Suzuki-Miyaura cross-coupling reactions of aryl chlorides in aqueous media. This work highlights that the microporous polymers not only play the role of support materials, but also protect the Pd species from aggregation and precipitation, hence, positively effect the catalysis activity. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The invasive phenotype of glioblastoma multiforme (GBM) is a hallmark of malignant process, yet the molecular mechanisms that dictate this locally invasive behavior remain poorly understood. Over-expression of PIAS3 effectively changes cell shape and inhibits GBM cell migration. We focused on the molecular target(s) of PIAS3 stimulated sumoylation, which play an important role in the inhibition of GBM cell motility. Here we report, through the immunoprecipitation with SUMO1 antibody, followed by proteomic analysis, the identification of vimentin (vimentin354), a nuclear component in GBM cells, as the main target of sumoylation promoted by PIAS3.

Li J.,Northwest University, China | Jia H.,Lanzhou University
Plant Physiology and Biochemistry | Year: 2013

The phytohormone auxin participates in lateral root formation and primary root growth in plants. The auxin gradient formation is mainly regulated by the direction of polar auxin transport (PAT). PAT requires PIN family proteins, which are auxin transport facilitators and contribute to the establishment and maintenance of auxin gradients and mediate multiple developmental processes. Here, we report the effect of the 3', 5'-cyclic guanosine monophosphate (cGMP), an important second messenger, on postembryonic developmental of Arabidopsis lateral root. We find that enhanced cGMP level through the application of the membrane permeable cGMP analog 8-Br-cGMP, promotes the initiation of lateral root primordia and formation of lateral root. 6-Anilino-5,8-quinolinedione (Ly83583, the guanylate cyclase inhibitor) negatively regulates the process. cGMP also mediates acropetal auxin transport and basipetal auxin transport in the root. We further find that 8-Br-cGMP and Ly83583 change the expression of auxin transport genes and alter the polar localization and expression of PIN1 and PIN2 proteins. Moreover, Ly83583 affects actin organization and localization. Taken together, we propose that cGMP affects auxin transport and auxin gradient through modulation PINs proteins localization and expression. cGMP regulates postembryonic formation of Arabidopsis lateral root through the crosstalk with PAT. © 2013 Elsevier Masson SAS.

Liu G.,Central China Normal University | Song D.,Central China Normal University | Chen F.,Lanzhou University
Talanta | Year: 2013

A label-free immunosensor based on SWNTs modified GC electrodes has been developed for the direct detection of paraoxon. Based on aryldiazonium salt chemistry, forest of SWNTs can be vertically aligned on mixed monolayers of aryldiazonium salt modified GC electrodes by CC bonding, which provides an interface showing efficient electron transfer between biomolecules. PEG molecules were introduced to the interface to resist non-specific protein adsorption. Ferrocenedimethylamine (FDMA) was subsequently attached to the ends of SWNTs through the amide bonding followed by the attachment of epitope i.e., paraoxon hapten to which a paraoxon antibody would bind. This immunosensor shows good selectivity and high specificity to paraoxon, and is functional for the detection of paraoxon in both laboratory and field by a displacement assay. There is a linear relationship between electrochemical signal of FDMA and the concentration of paraoxon over the range of 2-2500 ppb with a lowest detected limit of 2 ppb in 0.1 M phosphate buffer at pH 7.0. The SWNTs based amperometric immunosensor provides an opportunity to develop the sensing system for on-site sensitive detection of a spectrum of insecticides. © 2012 Elsevier B.V.

Wang C.,Lanzhou University
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji | Year: 2016

Genetic drift is one of the difficulties in teaching genetics due to its randomness and probability which could easily cause conceptual misunderstanding. The “sampling error" in its definition is often misunderstood because of the research method of “sampling", which disturbs the results and causes the random changes in allele frequency. I analyzed and compared the definitions of genetic drift in domestic and international genetic textbooks, and found that the definitions containing “sampling error" are widely adopted but are interpreted correctly in only a few textbooks. Here, the history of research on genetic drift, i.e., the contributions of Wright, Fisher and Kimura, is introduced. Moreover, I particularly describe two representative articles recently published about genetic drift teaching of undergraduates, which point out that misconceptions are inevitable for undergraduates during the studying process and also provide a preliminary solution. Combined with my own teaching practice, I suggest that the definition of genetic drift containing “sampling error" can be adopted with further interpretation, i.e., “sampling error" is random sampling among gametes when generating the next generation of alleles which is equivalent to a random sampling of all gametes participating in mating in gamete pool and has no relationship with artificial sampling in general genetics studies. This article may provide some help in genetics teaching.

Xie M.,Sichuan University | Xie M.,Lanzhou University | Liu X.,Sichuan University | Wu X.,Sichuan University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2013

Add a ring: A catalytic asymmetric [8+2] cycloaddition reaction of azaheptafulvenes with alkylidene malonates was developed. When employing catalytic amounts of a chiral N,N-dioxide L-NiII complex, the reaction afforded functionalized cycloheptatriene-fused pyrrole derivatives in excellent yields (up to 99 %), diastereoselectivities (>95:5 d.r.), and enantioselectivities (91-97 % ee) under mild conditions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhou M.-B.,Hunan University | Song R.-J.,Hunan University | Wang C.-Y.,Hunan University | Li J.-H.,Hunan University | Li J.-H.,Lanzhou University
Angewandte Chemie - International Edition | Year: 2013

Silver forges the ring: A new and practical silver-catalyzed [5+2] cycloaddition method has been developed for the synthesis of azepines through the formation of four new chemical bonds between a γ-amino ketone and an alkyne in one step. This method provides a new hetero-[5+2] cycloaddition strategy for the construction of seven-membered ring systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In this work, we have systematically studied the structural, energetic and electronic properties of graphene functionalized with carbene groups by using density functional theory. Introducing a low concentration of CCl2 group in graphene was studied in detail by DFT, and closed cyclopropane-like three-membered ring structure was formed, meanwhile, the potential candidate carbene groups CR2 (R = H, F, CH3, CN, NO2, OCH3, CCH, C6H5) were added to graphene sheet, and CR2 (R = H, NO2, CH3) groups were expected to be good reactive species to covalently modify graphene. The graphene functionalization with carbene groups above can open graphene's band gap. More CCl2 molecules were added to graphene, and different concentrations of CCl2 group can tune graphene's band gap. In addition, the addition of CCl2 group to graphene edges was investigated, and the stronger binding energy was found. Multiple CCl2 molecules preferred to be bound with the same edge of graphene nanoribbon. This work provides an insight into the detailed molecular mechanism of graphene functionalization with carbene groups. © 2014 Elsevier B.V.

The subvastus and medial parapatellar approaches are 2 commonly performed techniques in total knee arthroplasty, but the optimal approach for total knee arthroplasty remains controversial. The purpose of this study was to compare the effectiveness and safety of the subvastus vs medial parapatellar approach.The PubMed, Embase, Cochrane Library, Inter-Services Intelligence Web of Knowledge, and Chinese Biomedical Literature databases were searched for eligible quasi-randomized, controlled and randomized, controlled trials. Two authors independently extracted data and assessed the methodological quality of the included studies according to the Cochrane handbook version 5.1.0. Statistical analysis was performed using Review Manager version 5.1 software. Eight randomized, controlled trials and 1 quasi-randomized, controlled trial involving 940 primary total knee arthroplasties were included for meta-analysis. Meta-analysis revealed significant differences favoring the subvastus group in Knee Society Score in terms of function at 4 to 6 weeks (weighted mean difference [WMD]=5.09; 95% confidence interval [CI], 3.08 to 7.09; P<.01) and knee score at 12 months (WMD=2.17; 95% CI, 0.01 to 4.34; P=.05) and lateral retinacular release (odds ratio=0.34; 95% CI, 0.14 to 0.79; P=.01) when compared with the medial parapatellar approach. However, both groups showed similar results in range of motion (P>.05), operative time (WMD=2.15; 95% CI, -3.61 to 7.35; P=.42), blood loss (WMD= -31.07; 95% CI, -91.89 to 29.75; P=.32), hospital stay (WMD= -0.18; 95% CI, -0.67 to 0.31; P=.47), and postoperative complications (P>.05). Copyright 2012, SLACK Incorporated.

Zhang Z.,University of Aarhus | Song J.,University of Aarhus | Song J.,Lanzhou University | Besenbacher F.,University of Aarhus | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

Efficient self-assembly: Self-assembly of DNA nanostructures at room temperature was achieved by incubating the component strands in the presence of a denaturing agent (30-40% formamide). This isothermal method is efficient for assembly of both DNA origami (purple, see scheme) and single-stranded tile (SST, blue) structures, as well as an SST ribbon growing on an origami template. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cui X.,CAS Lanzhou Institute of Chemical Physics | Cui X.,Lanzhou University | Deng Y.,CAS Lanzhou Institute of Chemical Physics | Shi F.,CAS Lanzhou Institute of Chemical Physics
ACS Catalysis | Year: 2013

As the sustainable and promising hydrogen source, here, glycerol was directly used as the hydrogen source for the reductive amination of alcohol using nitrobenzene as the starting material. The amination of alcohols, especially aliphatic alcohols with different structures, was realized, and mono- or disubstituted amines were synthesized with excellent yields. The reaction mechanism was also explored. © 2013 American Chemical Society.

Chen Z.,Zhejiang University | Yan Q.,Zhejiang University | Liu Z.,Zhejiang University | Xu Y.,Zhejiang University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

NNNifty targets: In a straightforward copper-mediated synthesis of 1,4-disubstituted and 1,4,5-trisubstituted 1,2,3-triazoles, readily available aniline and N-tosylhydrazone substrates underwent cyclization through CN and NN bond formation (see scheme; Piv=pivaloyl, Ts=p-toluenesulfonyl). This method enables the preparation of 1,2,3-triazoles with high efficiency under mild conditions without the use of azides. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xu G.F.,Lanzhou University
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi | Year: 2012

To explore the changes of surface antigen and function of rituximab on dendritic cells derived from patients with Primary immune thrombocytopenia (ITP) to further understand the effective mechanism of immunotherapy. The peripheral blood mononuclear cells (PBMCs) were isolated from remission patients with ITP before and after low-dose rituximab infusion, and the PMNCs were stimulated for 5 days by rhGM-CSF and rhlL-4 in 5% CO2 air at 37°C incubator. Then all of DCs were cultured with TNF-α for 48 hours. The morphology of DCs was monitored under inverted microscope daily, and the surface antigens of the DCs were analysed by flow cytometry, meanwhile the levels of IL-12p70 and TGF-β1 in supernatants were detected by ELISA, mix lymphocyte reaction was performed by MTT assay. (1) Rituximab-treated-DCs showed no obvious tree-like protruding compared with untreated-DCs. The former cells were small and most of nucleus were centric. (2) The expressions of HLA-DR, CD80, CD83 and CD86 on rituximab-treated-DCs \[56.37 ± 3.95)%, (36.41 ± 2.82)%, (30.45 ± 4.61)% and (41.98 ± 4.17)%, respectively\] were significantly lower than those untreated-DCs \[(73.71 ± 7.61)%, (55.14 ± 7.30)%, (80.91 ± 7.09)% and (59.03 ± 3.43)%, respectively\](all P < 0.05), the concentration of IL-12p70 was significantly lower, \[(66.87 ± 4.29)% vs (50.17 ± 14.52)%\], while that of TGF-β1 \[(9.70 ± 0.31)%\] higher than the untreated-DCs \[(2.70 ± 0.36)%\] (P < 0.05). (3) The abilities to activate T cells proliferation of rituximab-treated-DCs reduced compared with untreated-DCs. The surface antigen of ITP-DCs and the concentration of IL-12p70 reduced after the low-dose rituximab infusion. The abilities to activate T cells proliferation reduced while the concentration of TGF-β1 increased. Rituximab may achieve its therapeutic effect on ITP by downregulating the immunoreactivity of DCs.

Li R.,CAS Lanzhou Institute of Modern Physics | Ren J.-R.,Lanzhou University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

We consider the scalar, vector and spinor field perturbations in the background of self-dual warped AdS3 black hole of topological massive gravity. The corresponding exact expressions for quasinormal modes are obtained by analytically solving the perturbation equations and imposing the vanishing Dirichlet boundary condition at asymptotic infinity. It is expected that the quasinormal modes agree with the poles of retarded Green's functions of the CFT dual to self-dual warped AdS3 black hole. Our results provide a quantitative test of the warped AdS/CFT correspondence. © 2011 American Physical Society.

Zhang H.F.,Lanzhou University | Royer G.,CNRS Laboratory of Subatomic Physics and Associated Technologies | Li J.Q.,CAS Lanzhou Institute of Modern Physics
Physical Review C - Nuclear Physics | Year: 2011

A study of the assault frequency and preformation factor of the α-decay description is performed from the experimental α-decay constant and the penetration probabilities calculated from the generalized liquid-drop model (GLDM) potential barriers. To determine the assault frequency a quantum-mechanical method using a harmonic oscillator is introduced and leads to values of around 1021 s-1, similar to the ones calculated within the classical method. The preformation probability is around 10 -1-10-2. The results for even-even Po isotopes are discussed for illustration. While the assault frequency presents only a shallow minimum in the vicinity of the magic neutron number 126, the preformation factor and mainly the penetrability probability diminish strongly around N=126. © 2011 American Physical Society.

Bai Z.G.,Lanzhou University
Cochrane database of systematic reviews (Online) | Year: 2012

Syphilis is a complex systemic disease caused by a spirochete, Treponema pallidum. The World Health Organization estimates that at least 12 million people worldwide are currently infected with syphilis. In this review we compared two current standards of treatment for early syphilis, benzathine benzylpenicillin (penicillin G) and azithromycin. To evaluate the efficacy and safety of azithromycin versus benzathine penicillin (penicillin G) for early syphilis. We searched the following databases using the search terms detailed in Appendix 1: the Cochrane Sexually Transmitted Diseases Group Specialized Register (July 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) published in The Cochrane Library (Issue 7 2011), MEDLINE (1948 to July 2011), EMBASE (1980 to July 2011), PsycINFO (1806 to July 2011) and the Chinese Biological Medicine Literature Database (CBM) (1978 to 2011). The search was not limited by language. Randomized controlled trials comparing azithromycin with benzathine penicillin G at any dose for the treatment of early syphilis. Two review authors independently applied the inclusion criteria to potential studies, with any disagreements resolved by discussion. The risk of bias of each study was assessed by the same two review authors. We pooled data using an odds ratio (OR). Three studies (generating four eligible study comparisons) were included. One study is ongoing. There was no statistically significant difference between azithromycin and benzathine penicillin treatment in the odds of cure (OR 1.04, 95% CI 0.69 to 1.56); nor any difference at three months (OR 0.97, 95% CI 0.62 to 1.50), six months (OR 1.09, 95% CI 0.76 to 1.54) or nine months (OR 1.45, 95% CI 0.46 to 6.42). Subgroup analysis by primary and latent syphilis and by dose of azithromycin (2 g and 4 g) did not explain the variation between the study results. The reporting of computed mild to tolerated adverse events, from two included trials, indicated no statistically significant difference between azithromycin and benzathine penicillin (OR 1.43, 95% CI 0.42 to 4.95), although with a high level of heterogeneity (P = 0.05, I(2) = 74%). Differences in the odds of cure did not reach statistical significance when azithromycin was compared with benzathine penicillin for the treatment of early syphilis. No definitive conclusion can be made regarding the relative safety of benzathine penicillin G and azithromycin for early syphilis. Further studies on the utility of benzathine penicillin G for early syphilis are warranted.

Guo J.,Lanzhou University
Cochrane database of systematic reviews (Online) | Year: 2012

A subarachnoid hemorrhage (SAH) is a serious and potentially life-threatening condition where blood leaks out of blood vessels over the surface of the brain. Delayed ischemic neurological deficit (DIND) and the related feature of vasospasm, where patients experience a delayed deterioration, have long been recognized as the leading potentially treatable cause of death and disability in patients with SAH. Endothelin is a potent, long-lasting endogenous vasoconstrictor that has been implicated in the pathogenesis of DIND. Therefore, endothelin receptor antagonists (ETAs) have emerged as a promising therapeutic option for SAH-induced cerebral vasospasm. To assess the efficacy and tolerability of ETAs for SAH. We searched the Cochrane Stroke Group Trials Register (December 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 11), MEDLINE (1950 to December 2011), EMBASE (1946 to December 2011) and the Chinese Biomedical Database (1978 to December 2011). In an effort to identify further published, unpublished and ongoing trials we searched additional Chinese databases, ongoing trials registers, Google Scholar and Medical Matrix, handsearched journals, scanned reference lists, and contacted researchers and pharmaceutical companies. We only included randomized controlled trials (RCTs) that compared an ETA with placebo for SAH in adult (18 years of age or older) patients who met the diagnostic criteria for SAH based on clinical symptoms, with confirmation on computerized tomography scan results or angiography. Two review authors independently selected RCTs according to the inclusion criteria. We resolved disagreements by discussion with a third review author. Two review authors independently selected relevant articles and assessed their eligibility according to the inclusion and exclusion criteria. We resolved disagreements by discussion with a third review author. We used the random-effects model and expressed the results as risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with 95% confidence intervals (CI). We included four RCTs with 2024 participants that compared ETAs with placebo for SAH. All RCTs were multicenter, double-blind studies with a low risk of bias. ETAs reduced the incidence of DIND (RR 0.80; 95% CI 0.67 to 0.95) and angiographic vasospasm (RR 0.62; 95% CI 0.52 to 0.72) but did not reduce the incidence of unfavorable outcomes (RR 0.87; 95% CI 0.74 to 1.02) or mortality (RR 1.05; 95% CI 0.77 to 1.45). ETAs increased the incidence of hypotension (RR 2.53; 95% CI 1.77 to 3.62) and pneumonia (RR 1.56; 95% CI 1.23 to 1.97). ETAs appear to reduce DIND and angiographic vasospasm but there were adverse events and the impact on clinical outcome is unclear. Additional well-designed RCTs are needed.

To evaluate the relationship between exposure to gaseous air pollutants (NO2 and SO2) and daily hospital admissions for respiratory diseases. After controlling long time trend, the "day of week" effect and confounding factors of meteorology, a semi-parametric generalized additive model (GAM) was used to analyze the exposure-effect relationship between gaseous air pollutants and daily respiratory hospital visits from 2001 to 2005 in Lanzhou city. Both NO2 and SO2 have positive relationships with residents' hospital visits for respiratory complaints. In single-pollutant models, the best fits for NO2 and SO2 were one day after (Lag1) and the same day visit (Lag0). With an IQR concentration increase in NO2 (Lag1) and SO2 (Lag0), the relative risks of daily hospital admissions for respiratory diseases were 1.060 (95% CI 1.046-1.074) and 1.048 (95% CI 1.031-1.065), respectively. The susceptible populations were female and the elderly. The health effect of gaseous air pollution was more obvious in autumn and winter. The ambient NO2 and SO2 concentrations have an adverse effect on daily hospital visits for respiratory diseases of residents in Lanzhou.

Fan J.-H.,Hunan University | Wei W.-T.,Hunan University | Zhou M.-B.,Hunan University | Song R.-J.,Hunan University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014

The oxidative interception of various σ-alkyl palladium(II) intermediates with additional reagents for the difunctionalization of alkenes is an important research area. A new palladium-catalyzed oxidative difunctionalization reaction of alkenes with α-carbonyl alkyl bromides is described, in which the σ-alkyl palladium(II) intermediate is generated through a Heck insertion and trapped using an aryl C(sp2)-H bond. This method can be applied to various α-carbonyl alkyl bromides, including primary, secondary, and tertiary α-bromoalkyl esters, ketones, and amides. Indolinone synthesis: A new palladium-catalyzed oxidative difunctionalization reaction of N-arylalkenes with primary, secondary, and tertiary α-carbonyl alkyl bromides proceeds through a radical process and provides indolin-2-ones in moderate to excellent yields. The reaction is initiated by a Heck insertion followed by interception of the σ-alkyl palladium(II) intermediate with aryl C(sp2)-H bonds. dppe=1,2-bis(diphenylphosphino)ethane. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang J.,Lanzhou University
International Journal of Fracture | Year: 2010

This paper aims to study the size- and shape-dependent steady-state pull-off force in molecular adhesion between two soft elastic materials. The adhesion consists of a patch of non-covalent bonds formed between ligand and receptor molecules on opposing adhesion surfaces. Classical contact mechanics is used to model the deformation of elastic materials while Bell's model is adopted to describe stochastic breaking/reforming of molecular bonds. A coupled elastic-stochastic model is established to show that there exists a critical adhesion size, which leads to a critical stress concentration index after proper normalization, beyond which stress concentration near the contact edge causes crack like failure of the adhesion patch governed by Griffith's criterion and below which the pull-off traction is saturated at a constant strength governed by Bell's model of molecular adhesion. In addition to size effect, optimal adhesion can also be achieved by designing the shape of the contact surfaces, although it is sensitive to small variations in shape at large adhesion size or stress concentration index. A robust, shape-insensitive high-strength adhesion state becomes possible when the adhesion size or the stress concentration index is sufficiently small. © 2010 Springer Science+Business Media B.V.

Liu X.Y.,Lanzhou University
The Journal of international medical research | Year: 2012

To investigate the effects and mechanisms of sesquiterpene (+)-chabranol on proliferation of a panel of four human tumour cell lines (BGC-823, SGC-7901, SSMC-7721 and HepG2). Cell viability was assessed using a standard methyltetrazolium assay; cell-cycle analysis of BGC-823 cells was performed by flow cytometry. Transmission electron microscopy (TEM) was used to examine the ultrastructure of BGC-823 cells exposed to (+)-chabranol. Apoptosis was investigated by evaluating DNA laddering, using gel electrophoresis. (+)-Chabranol had a marked time- and concentration-dependent inhibitory effect on BGC-823 cell proliferation. The effect was less marked in SGC-7901, SSMC-7721 and HepG2 cells. Exposure of BGC-823 cells to (+)-chabranol arrested the cell cycle at G(1). Evidence of apoptosis and autophagy was observed by TEM; DNA laddering in BGC-823 cells supported the presence of apoptosis. This study suggested that (+)-chabranol has antitumour activity against BGC-823 cells, and may exert its action by inhibition of proliferation and induction of apoptosis and autophagy. With further development, (+)-chabranol may represent a potential novel treatment for poorly differentiated gastric cancer.

Liu Y.,Sichuan University | Hu H.,Sichuan University | Zheng H.,Sichuan University | Xia Y.,Sichuan University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2014

Highly efficient catalytic asymmetric Claisen rearrangements of O-propargyl β-ketoesters and O-allyl β-ketoesters have been accomplished under mild reaction conditions. In the presence of the chiral N,N′-dioxide/NiII complex, a wide range of allenyl/allyl-substituted all-carbon quaternary β-ketoesters was obtained in generally good yield (up to 99 %) and high diastereoselectivity (up to 99:1 d.r.) with excellent enantioselectivity (up to 99 % ee). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhou P.-P.,Beijing Computational Science Research Center | Zhou P.-P.,Lanzhou University | Zhang R.-Q.,City University of Hong Kong
Physical Chemistry Chemical Physics | Year: 2015

A series of benzene derivatives with different substituents adsorbed on graphene was investigated using a density-functional tight-binding method with a dispersion correction. Compared to benzene, the derivative with either an electron-withdrawing or -donating substituent exhibits stronger physisorption. Moreover, the steric size of the substituent is important in determining the adsorption strength, while the direction and the number of H atoms in the substituent affect the electron transfer from graphene. NBO analysis reveals that the stereoelectronic effect of the conjugation between the substituent and the benzene ring strongly influences the π⋯π interaction region between the molecule and graphene. The findings can deepen the understanding of the interaction between an aromatic molecule and graphene as well as the corresponding adsorption mechanism. © the Owner Societies 2015.

Wang M.Y.,Lanzhou University
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology | Year: 2012

This study was purposed to investigate the intercellular cell adhesion molecule-1 (ICAM-1) gene K469E (A/G) (rs5498) and K56M (A/T) (rs5491) single nucleotide polymorphisms (SNP) and soluble ICAM-1 (sICAM-1) levels in plasma in three Chinese populations of Yugur, Tibetan and Han nationalities, to analyze comparatively the genotypes and allele frequencies distribution in different ethnic groups, and to explore the effects of ICAM-1 K469E and K56M polymorphism and sICAM-1 levels in plasma. EDTA-anticoagulant venous blood from Yugur(327 cases), Tibetan (400 cases) and Han (126 cases) people was collected, the DNA was extracted by using whole blood genomic DNA extraction kit, DNA SNP were analyzed by PCR-RFLP, genotype was judged by gel scan imaging system after agarose gel electrophoresis, the gene sequence was determined and the distribution of ICAM-1 genotypes and allele frequencies were compared among different ethnic groups, besides, the group representativeness was tested via the Hardy-Weinberg genetic equilibrium. Finally, the human sICAM-1 plasma levels were detected by using human ICAM-1 ELISA kit. The results showed that DNA sequencing result was consistent with PCR-RFLP analysis. In Yugur, Tibetan and Han nationalities, the KK, KE and EE three genotypes at ICAM-1 K469E gene locus were detected, the genotype distribution was not statistically significantly different, while the K, E allele frequency distribution was statistically significantly different (P < 0.05). Both of genotype and allele frequency distribution between Yugur, Tibetan and Han nationalities were statistically significantly different (P < 0.05). In K56M site only KK, KM two genotypes were detected, but the MM genotype was not detected in the three ethnic groups; the difference of two genotypes and K, M allele frequencies between Yugur and Han population was statistically significantly different (P < 0.05). Among three ethnic groups, the sex ratio and age distribution of K469E, K56M genotypes and allele frequencies of ICAM-1 gene were not significantly different, and distribution was in accordance with Hardy-Weinberg genetic equilibrium (P > 0.05). The plasma sICAM-1 level at ICAM-1 K469E allele locus in K individuals [(253 ± 122), (185 ± 97) μg/L] was higher than that at non-K allele [(145 ± 110) μg/L, P < 0.01]; the plasma sICAM-1 level of ICAM-1 K56M sites with KK genotype [(253 ± 122) μg/L] was higher than that of the KM genotypes [(168 ± 103) μg/L, P < 0.01]. In Yugur and Tibetan groups, the plasma sICAM-1 levels [(224 ± 80), (214 ± 111) μg/L] were higher than that in the Han group [(175 ± 125)μg/L, P < 0.05]. Pairwise comparison indicated that the plasma sICAM-1 levels between Yugur and Han group were statistically significantly different (P < 0.01), that was significantly different between Tibetan and Han group (P < 0.05). It is concluded that in Yugur, Tibetan and Han population, the genotypes and gene frequencies of two amino acid sites K469E and K56M in ICAM-1 were KK/KE-type, KK-type and K allele, moreover, the ratio of them in Yugur and Tibetan group was higher than that in Han, while there is not significant difference in sex ratio and age distribution, therefore, ICAM-1 genotype and allele frequency distribution in this study had ethnic representativeness. ICAM-1 gene K469E and K56M polymorphisms were likely to affect the plasma sICAM-1 expression level. K469E gene K allele may be a genetic risk factor, while K56M gene M allele a may be genetic protective factor for some diseases.

Lee S.,Umea University | Holme P.,Umea University | Holme P.,Sungkyunkwan University | Wu Z.-X.,Umea University | Wu Z.-X.,Lanzhou University
Physical Review Letters | Year: 2011

We investigate a game-theoretic model of a social system where both the rules of the game and the interaction structure are shaped by the behavior of the agents. We call this type of model, with several types of feedback couplings from the behavior of the agents to their environment, a multiadaptive game. Our model has a complex behavior with several regimes of different dynamic behavior accompanied by different network topological properties. Some of these regimes are characterized by heterogeneous, hierarchical interaction networks, where cooperation and network topology coemerge from the dynamics. © 2011 American Physical Society.

Hobein M.,Albanova University Center | Solders A.,Albanova University Center | Suhonen M.,Albanova University Center | Liu Y.,Albanova University Center | And 2 more authors.
Physical Review Letters | Year: 2011

Externally, in an electron beam ion trap, generated Ar16⊃+ ions were retrapped in a Penning trap and evaporatively cooled in their axial motion. The cooling was observed by a novel extraction technique based on the excitation of a coherent axial oscillation which yields short ion bunches of well-defined energies. The initial temperature of the ion cloud was decreased by a factor of more than 140 within 1 s, while the phase-space density of the coldest extracted ion pulses was increased by a factor of up to about 9. © 2011 The American Physical Society.

Yang Y.,Hunan University | Zhou M.-B.,Hunan University | Ouyang X.-H.,Hunan University | Pi R.,Hunan University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2015

A rhodium(III)-catalyzed [3+2]/[5+2] annulation of 4-aryl 1-tosyl-1,2,3-triazoles with internal alkynes is presented. This transformation provides straightforward access to indeno[1,7-cd]azepine architectures through a sequence involving the formation of a rhodium(III) azavinyl carbene, dual C(sp2)-H functionalization, and [3+2]/[5+2] annulation. A quantum leap in complexity: A general strategy based on rhodium(III) azavinyl carbene intermediates was established for the oxidative [3+2]/[5+2] annulation of 4-aryl 1-tosyl-1,2,3-triazoles with alkynes. This general method provided densely functionalized indeno[1,7-cd]azepine architectures with excellent selectivity through the functionalization of two C(sp2)-H bonds (see scheme; Cp∗=pentamethylcyclopentadienyl, Ts= p-toluenesulfonyl). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fu Q.,Lanzhou University | Fu Q.,University of Washington | Feng S.,University of Arkansas
Journal of Geophysical Research B: Solid Earth | Year: 2014

The dryness of terrestrial climate can be measured by the ratio of annual precipitation (P) to potential evapotranspiration (PET), where the latter represents the evaporative demand of the atmosphere, which depends on the surface air temperature, relative humidity, wind speed, and available energy. This study examines how the terrestrial mean aridity responds to global warming in terms of P/PET using the Coupled Model Intercomparison Project phase 5 transient CO2 increase to 2×CO2 simulations. We show that the (percentage) increase (rate) in P averaged over land is ∼1.7%/°C ocean mean surface air temperature increase, while the increase in PET is 5.3%/°C, leading to a decrease in P/PET (i.e., a drier terrestrial climate) by ∼3.4%/°C. Noting a similar rate of percentage increase in P over land to that in evaporation (E) over ocean,we propose a framework for examining the change in P/PET, in which we compare the change in PET over land and E over ocean, both expressed using the Penman-Monteith formula. We show that a drier terrestrial climate is caused by (i) enhanced land warming relative to the ocean, (ii) a decrease in relative humidity over land but an increase over ocean, (iii) part of increase in net downward surface radiation going into the deep ocean, and (iv) different responses of PET over land and E over ocean for given changes in atmospheric conditions (largely associated with changes in temperatures). The relative contributions to the change in terrestrial mean aridity from these four factors are about 35%, 35%, 15%, and 15%, respectively. The slight slowdown of the surface wind over both land and ocean has little impact on the terrestrial mean aridity. ©2014. American Geophysical Union. All Rights Reserved.

Zhang D.L.,Lanzhou University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2011

To study the chemical constituents of the leave of Paulownia tomentosa. The constituents were isolated by column chromatography and their structures were elucidated through spectroscopic analysis. The compounds were identified as apigenin(I), uteolin(II), homoeriodictyol(III), 3alpha-hydroxyurs-12-en-28-oic acid (IV),3beta,19alpha-dihydroxyurs-12en-28-oic acid (pomolic acid)(V),2alpha,3a-dihydroxyurs-12-en-28-oic acid(VI),ursolic acid (VII),2alpha,3beta-dihydroxyolean-12-en-28-oic acid (maslinic acid) (VIII), daucosterol(IX),beta-sitosterol(X). The compound I-X are obtained from the leave of Paulownia tomentosa (Thunb.) Steud for the first time.

Lung cancer is one of the most common cancer types in the world. An accurate diagnosis of lung cancer is crucial for early treatment and management. To perform a comprehensive meta-analysis to evaluate the diagnostic performance of dual time point 18F-fluorodexyglucose position emission tomography/computed tomography (FDG-PET/CT) and single time point 18FDG-PET/CT in the diagnosis of pulmonary nodules. PubMed (1966-2011.11), EMBASE (1974-2011.11), Web of Science (1972-2011.11), Cochrane Library (-2011.11), and four Chinese databases - CBM (1978-2011.11), CNKI (1994-2011.11), VIP (1989-2011.11), and Wanfang Database (1994-2011.11) - were searched. Summary sensitivity, summary specificity, summary diagnostic odds ratios (DOR), and summary positive likelihood ratios (LR+) and negative likelihood ratios (LR-) were obtained using Meta-Disc software. Summary receiver-operating characteristic (SROC) curves were used to evaluate the diagnostic performance of dual time point 18FDG-PET/CT and single time point 18FDG-PET/CT. The inclusion criteria were fulfilled by eight articles, with a total of 415 patients and 430 pulmonary nodules. Compared with the gold standard (pathology or clinical follow-up), the summary sensitivity of dual time point 18FDG-PET/CT was 79% (95%CI, 74.0-84.0%), and its summary specificity was 73% (95%CI, 65.0-79.0%); the summary LR+ was 2.61 (95%CI, 1.96-3.47), and the summary LR- was 0.29 (95%CI, 0.21-0.41); the summary DOR was 10.25 (95%CI, 5.79-18.14), and the area under the SROC curve (AUC) was 0.8244. The summary sensitivity for single time point 18FDG-PET/CT was 77% (95%CI, 71.9-82.3%), and its summary specificity was 59% (95%CI, 50.6-66.2%); the summary LR+ was 1.97 (95%CI, 1.32-2.93), and the summary LR- was 0.37 (95%CI, 0.29-0.49); the summary DOR was 6.39 (95%CI, 3.39-12.05), and the AUC was 0.8220. The results indicate that dual time point 18FDG-PET/CT and single time point 18FDG-PET/CT have similar accuracy in the differential diagnosis of pulmonary nodules. Dual time point 18FDG-PET/CT appears to be more specific than single time point 18FDG-PET/CT.

Qiu Q.-S.,Lanzhou University
Journal of Integrative Plant Biology | Year: 2012

The plant NHX gene family encodes Na +/H + antiporters which are crucial for salt tolerance, potassium homeostasis and cellular pH regulation. Understanding the role of NHX antiporters in membrane trafficking is becoming an increasingly interesting subject of study. Membrane trafficking is a central cellular process during which proteins, lipids and polysaccharides are continuously exchanged among membrane compartments. Yeast ScNhx1p, a prevacuole/vacuolar Na +/H + antiporter, plays an important role in regulating pH to control trafficking out of the endosome. Evidence begins to accumulate that plant NHX antiporters might function in regulating membrane trafficking in plants. © 2012 Institute of Botany, Chinese Academy of Sciences.

Chen S.,Soochow University of China | Xu Y.,Soochow University of China | Wan X.,Soochow University of China | Wan X.,Lanzhou University
Organic Letters | Year: 2011

A new N-sulfonyl formamidine synthesis was developed via NaI-catalyzed direct condensation of sulfonamide and formamide. The green methodology is featured by high atom economy, easily available starting materials, the lack of need for a transition-metal catalyst, no requirement of hazardous reagent, operational simplicity, and good tolerance with diverse functional groups. Mechanistic studies suggest that the protocol proceeds based upon in situ generated TsN•NaI. © 2011 American Chemical Society.

Wang Y.X.,Lanzhou University
Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology | Year: 2012

To investigate the clinical and molecular epidemiology characteristics of calicivirus and adenovirus in children for viral diarrhea in Lanzhou. Stool samples were collected from 295 children with diarrhea at the First Hospital of Lanzhou University, Gansu Province,China, between July 2010 and June 2011. Reverse transcription-polymerase chain reaction (RT-PCR) or PCR were used to detected calicivirus and adenovirus. The adenovirus positive samples were typed by nested PCR and multiple PCR. Of the 295 specimens, 13.2% (39/295) were positive for calicivirus, and 5.1% (15/295) were adenovirus. Typing and Phylogenetic analysis revealed that novirus GII-3 and adenovirus 41 were the dominant strains. Both calicivirus and adenovirus predominately affect children under the age of 2. In seasonal distribution, there was no obvious peak. Human calicivirus and adenovirus are important pathogens of viral diarrhea,it is important to develop long-term systematic surveillance.

Shao J.,Lanzhou University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2011

To establish the quantitative determination method and TLC identification of Meconopsis and study the Vis-UV spectrum character for fast identification. Meconopsis were identified by TLC, and the content of quercetin was determined by HPLC. The acid hydrolyze condition was HCl-80% MeOH(8:25) 90 degrees C calefaction by water for 1.5 hour. The condition of HPLC: Hypersil-Keystone-C18 (250 mm x 4.6 mm, 5 microm) column, MeOH-Water (50: 50) as mobile phase, detection wavelength at 360nm, flow rate at 1.0 mL/min, column temperature at 35 degrees C, quercetin showed a good linear relationship at a range of 0.01 - 0.12 microg, r =0.9997. The average recovery was 98.83%, and RSD was 1.69% (n = 9). The contents of quercetin in Meconopsis integrifolia and Meconopsis quintuplinervia of Gansu were 0.1135 mg/g and 0.0842 mg/g respectively. The method is simple, accurate and specific. It can be used for the quality control and fast identification of Meconopsis.

Mao Z.,CAS Dalian Institute of Chemical Physics | Huang F.,CAS Dalian Institute of Chemical Physics | Yu H.,Anshan Normal University | Chen J.,CAS Dalian Institute of Chemical Physics | And 3 more authors.
Chemistry - A European Journal | Year: 2014

The functionalization of internal olefins has been a challenging task in organic synthesis. Efficient CuII-catalyzed trifluoromethylation of internal olefins, that is, α-oxoketene dithioacetals, has been achieved by using Cu(OH)2 as a catalyst and TMSCF3 as a trifluoromethylating reagent. The push-pull effect from the polarized olefin substrates facilitates the internal olefinic C-H trifluoromethylation. Cyclic and acyclic dithioalkyl α-oxoketene acetals were used as the substrates and various substituents were tolerated. The internal olefinic C-H bond cleavage was not involved in the rate-determining step, and a mechanism that involves radicals is proposed based on a TEMPO-quenching experiment of the trifluoromethylation reaction. Further derivatization of the resultant CF 3 olefins led to multifunctionalized tetrasubstituted CF3 olefins and trifluoromethylated N-heterocycles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li J.,Peking University | Yu J.,Peking Tsinghua Center for Life science | Zhao J.,Peking University | Wang J.,Peking Tsinghua Center for Life science | And 8 more authors.
Nature Chemistry | Year: 2014

Employing small molecules or chemical reagents to modulate the function of an intracellular protein, particularly in a gain-of-function fashion, remains a challenge. In contrast to inhibitor-based loss-of-function approaches, methods based on a gain of function enable specific signalling pathways to be activated inside a cell. Here we report a chemical rescue strategy that uses a palladium-mediated deprotection reaction to activate a protein within living cells. We identify biocompatible and efficient palladium catalysts that cleave the propargyl carbamate group of a protected lysine analogue to generate a free lysine. The lysine analogue can be genetically and site-specifically incorporated into a protein, which enables control over the reaction site. This deprotection strategy is shown to work with a range of different cell lines and proteins. We further applied this biocompatible protection group/catalyst pair for caging and subsequent release of a crucial lysine residue in a bacterial Type III effector protein within host cells, which reveals details of its virulence mechanism. © 2014 Macmillan Publishers Limited.

Prion diseases are associated with misfolding and aggregation of prion protein (PrP). Cellular prion protein contains a disulfide bond linking Cys residues at positions 179 and 214. It has been proposed that this disulfide bond plays an important role in the conversion between cellular (PrP(C)) and the scrapie form of prion protein (PrP(Sc)). To probe the role of this disulfide bond in the stability and folding of prion protein, we employed molecular dynamics simulations to study the reduced prion protein and a variant of PrP in which the two cysteines were replaced by alanines residues. The simulations highlighted the changes that occurred upon breakage of the disulfide bond. Breakage of the disulfide bond resulted in a shift of H1, elongation of the native β-sheet and perturbation of the hydrophobic core of huPrP. The changes are similar to the conformational transitions of prion protein in low pH, in denaturing conditions or with pathogenic mutations, which indicate that rupture of the disulfide bond may lead to the misfolding of prion protein.

He J.,CAS Lanzhou Institute of Modern Physics | He J.,Lanzhou University | He J.,CAS Institute of Theoretical Physics
Physical Review C - Nuclear Physics | Year: 2014

The interaction mechanism of the Σ(1385) photoproduction from proton γp→K+Σ0(1385) is investigated within a Regge-plus-resonance approach based on the experimental data released by the CLAS Collaboration recently. The t channel and the u channel are responsible for the behaviors of differential cross sections at forward and backward angles, respectively. The contributions from nucleon resonances including N* and Δ*, which are determined by the predicted decay amplitudes in the constituent quark model, are found to be small, but the F35 state Δ(2000) is essential to reproduce the differential cross section. © 2014 American Physical Society.

Cai R.-G.,CAS Institute of Theoretical Physics | Wang Y.-Q.,Lanzhou University | Zhang H.-Q.,University of Lisbon
Journal of High Energy Physics | Year: 2014

We construct a holographic model of superconducting quantum interference device (SQUID) in the Einstein-Maxwell-complex scalar theory with a negative cosmological constant. The SQUID ring consists of two Josephson junctions which sit on two sides of a compactified spatial direction of a Schwarzschild-AdS black brane. These two junctions interfere with each other and then result in a total current depending on the magnetic flux, which can be deduced from the phase differences of the two Josephson junctions. The relation between the total current and the magnetic flux is obtained numerically. © 2014 SISSA.

Xiao S.,Lanzhou University | Zobel M.,University of Tartu | Szava-Kovats R.,University of Tartu | Partel M.,University of Tartu
Global Ecology and Biogeography | Year: 2010

Aim The diversity-productivity relationship is a controversial issue in ecology. Diversity is sometimes seen to increase with productivity but a unimodal relationship has often been reported. Competitive exclusion was cited initially to account for the decrease of diversity at high productivity. Subsequently, the roles of evolutionary history (species pool size) and dispersal rate have been acknowledged.We explore how the effects of species pool, dispersal and competition combine to produce different diversity-productivity relationships. Methods We use a series of simulations with a spatially explicit, individual-based model. Following empirical expectations, we used four scenarios to characterize species pool size along the productivity gradient (uniformly low and high, linear increase and unimodal). Similarly, the dispersal rate varied along the productivity gradient (uniformly low and high, and unimodal). We considered both neutral communities and communities with competitive exclusion. Results and main conclusions Our model predicts that competitive interactions will result in unimodal diversity-productivity relationships. The model often predicts unimodal patterns in neutral communities as well, although the decline in richness at high productivity is less than in competing communities. A positive diversity-productivity relationship is simulated for neutral communities when the species pool size increases with productivity and the dispersal rate is high. This scenario is probably more widespread in nature than the others since positive diversity-productivity relationships have been observed more frequently than previously expected, especially in the tropics and for woody species. Our simulated effects of species pool, dispersal and competition on diversity patterns can be linked to empirical observations to uncover mechanisms behind the diversity-productivity relationship. © 2010 Blackwell Publishing Ltd.

Li L.,Lanzhou University
Cochrane database of systematic reviews (Online) | Year: 2011

Venous thromboembolism (VTE) is common in clinical practice. The efficacy of statins in the primary prevention of VTE remains unproven. To assess the efficacy of statins in the primary prevention of VTE. The Cochrane Peripheral Vascular Diseases (PVD) Group searched their Specialised Register (last searched April 2011) and CENTRAL (2011, Issue 2). The authors searched MEDLINE (January 1966 to March 2011); EMBASE (1974 to March 2011); ISI Web of Knowledge (2001 to March 2011); the Chinese Biomedical Literature Database (1978 to March 2011) and other resources (including clinical trials registers, reference lists and presentations at various conferences. Randomised controlled trials (RCTs) that assessed statins were considered. The outcomes we evaluated were the rates of VTE, cardiovascular and cerebrovascular events, death and adverse events. Two authors independently selected RCTs against inclusion criteria. Disagreements were resolved by discussion with a third author. Data extraction was independently carried out by two authors. Disagreements were resolved by discussion with a third author. Two authors independently assessed the risk of bias according to a standard quality checklist provided by the PVD Group. We included one RCT (17 citations) with 17,802 participants that assessed rosuvastatin for preventing VTE. Our analysis showed that rosuvastatin reduced the incidence of VTE (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.86) and deep vein thrombosis (DVT) (OR 0.45, 95% CI 0.25 to 0.79), the risk of any (fatal and non-fatal) myocardial infarction (MI) (OR 0.45, 95% CI 0.30 to 0.69), any (fatal and non-fatal) stroke (OR 0.51, 95% CI 0.34 to 0.78), but did not reduce the incidence of pulmonary embolism (PE) (OR 0.77, 95% CI 0.41 to 1.46) and death after VTE (OR 0.50, 95% CI 0.20 to 1.24). Rosuvastatin did not reduce the incidence of any serious adverse event (OR 0.95, 95% CI 0.90 to 1.06). Available evidence showed that rosuvastatin was associated with a reduced incidence of VTE, but the evidence was limited to a single RCT. Randomised controlled trials of statins (including rosuvastatin) are needed to evaluate the efficacy of statins in the prevention of VTE.

Liu P.,Lanzhou University
Industrial and Engineering Chemistry Research | Year: 2013

Carbon nanotubes (CNTs) are extensively explored in materials science due to their unique structure and consequent mystical properties. CNTs are enjoying increasing popularity as building blocks for novel drug delivery systems as well as for bioimaging and biosensing. The recent strategies to functionalize CNTs have resulted in the generation of biocompatible and water-soluble CNTs that are well suited for high treatment efficacy and minimum side effects for future cancer therapies with low drug doses. This review covers the latest advances in the strategies for the modification of CNTs (with inorganic nanoparticles, small organic molecules, polymers, or bioactive materials), with an emphasis on the development of functional biological nanointerfaces as drug vehicles, after a simple introduction of the toxicity of CNTs. The translation of these systems into clinical practice and an outlook into future approaches are also discussed. © 2013 American Chemical Society.

Xu H.,Northwest University, China | Xu H.,Lanzhou University | Fan L.-L.,Northwest University, China
European Journal of Medicinal Chemistry | Year: 2011

A series of new 5,6-dihydro-indolo[1,2-a]quinoxaline derivatives has been prepared in moderate to excellent yields from 2-(indol-1-yl)phenylamines with aromatic aldehydes by an efficient and economical iron-catalyzed Pictet-Spengler reaction. Meanwhile, as compared with hymexazol, a commercially available agricultural fungicide at the concentration of 50 μg/mL, some 5,6-dihydro-indolo[1,2-a]quinoxalines exhibited promising antifungal activities in vitro against the phytopathogenic fungi, and might be considered as novel promising lead candidates for further design and synthesis of agricultural fungicides. © 2011 Elsevier Masson SAS. All rights reserved.

Qin H.,Peking University | Xu Z.,Peking University | Cui Y.,Peking University | Jia Y.,Lanzhou University
Angewandte Chemie - International Edition | Year: 2011

A photo op: The concise total syntheses of (±)-decursivine and (±)-serotobenine were achieved by using the titled cascade reaction, which is modeled on the biomimetic pathway. The synthesis of (±)-decursivine, which exhibits antimalarial activity, was carried out in five steps without using protecting groups. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blande J.D.,University of Eastern Finland | Holopainen J.K.,University of Eastern Finland | Li T.,Lanzhou University
Ecology Letters | Year: 2010

Volatile organic compounds (VOCs) emitted by damaged plants convey information to undamaged neighbouring plants, and previous research has shown that these signals are effective over short distances in nature. Many herbivore-induced VOCs react with ozone, which is the most important tropospheric air pollutant in rural areas. We used extrafloral nectar (EFN) secretion as a phenotypic indicator of between-plant communication in Phaseolus lunatus L. (Lima bean) and show that an ozone-rich (80 ppb) atmosphere reduces the distance over which signalling occurs. We found that ozone degrades several herbivore-induced VOCs, a likely mechanism reducing communication distances. Direct exposure to 80-ppb ozone did not affect the VOC emissions from P. lunatus. In addition, we demonstrated that high ozone concentrations, 120 and 160 ppb, induced EFN secretion in exposed plants, whereas more moderate concentrations, 80 and 100 ppb, did not. This suggests that ozone can play a complex role in the indirect defence of P. lunatus. © 2010 Blackwell Publishing Ltd/CNRS.

Zhou W.-C.,Lanzhou University | Zhang Q.-B.,Fudan University | Qiao L.,University of Sydney
World Journal of Gastroenterology | Year: 2014

Liver cirrhosis is the final pathological result of various chronic liver diseases, and fibrosis is the precursor of cirrhosis. Many types of cells, cytokines and miRNAs are involved in the initiation and progression of liver fibrosis and cirrhosis. Activation of hepatic stellate cells (HSCs) is a pivotal event in fibrosis. Defenestration and capillarization of liver sinusoidal endothelial cells are major contributing factors to hepatic dysfunction in liver cirrhosis. Activated Kupffer cells destroy hepatocytes and stimulate the activation of HSCs. Repeated cycles of apoptosis and regeneration of hepatocytes contribute to pathogenesis of cirrhosis. At the molecular level, many cytokines are involved in mediation of signaling pathways that regulate activation of HSCs and fibrogenesis. Recently, miRNAs as a post-transcriptional regulator have been found to play a key role in fibrosis and cirrhosis. Robust animal models of liver fibrosis and cirrhosis, as well as the recently identified critical cellular and molecular factors involved in the development of liver fibrosis and cirrhosis will facilitate the development of more effective therapeutic approaches for these conditions. © 2014 Baishideng Publishing Group Inc. All rights reserved.

He J.,CAS Lanzhou Institute of Modern Physics | He J.,Lanzhou University | He J.,CAS Institute of Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

Very recently, two hidden-charmed resonances Pc(4380) and Pc(4450) consistent with pentaquark states were observed at the LHCb detector. The two Pc states locate just below the D-σc* and D-*σc thresholds with mass of gaps about 5 and 15 MeV, respectively. Inspired by this fact we perform a dynamical investigation about the D-σc*(2520) and D-*σc(2455) interactions which are described by the meson exchanges. A bound state which carries spin-parity JP=3/2- is produced from the D-σc*(2520) interaction, which is consistent with the Pc(4380) observed at the LHCb detector. From the D*σc(2455) interaction, a bound state with 5/2+ is produced, which can be related to the Pc(4450). The results suggest that the Pc(4380) and Pc(4450) are good candidates of D-σc*(2520) and D-*σc(2455) molecular states, respectively. © 2015.

Jia C.,Martin Luther University of Halle Wittenberg | Jia C.,Lanzhou University | Berakdar J.,Martin Luther University of Halle Wittenberg
Applied Physics Letters | Year: 2011

Thermoelectric transport across normal-metal/helical-multiferroic/ ferromagnetic heterojunctions is theoretically investigated. We find an anisotropic charge and spin thermopower with a C2v symmetry. The angular dependence on the magnetization orientation of the ferromagnetic layer is substantiated by a phenomenological theory based on the symmetry of the effective spin-orbit interaction induced by the topology of the spiral magnetic order in the multiferroic barrier. © 2011 American Institute of Physics.

Sang P.,Zhejiang University | Chen Z.,Zhejiang University | Zou J.,Zhejiang University | Zhang Y.,Zhejiang University | Zhang Y.,Lanzhou University
Green Chemistry | Year: 2013

An efficient and convenient method was developed for the preparation of 3-sulfenylindoles via a K2CO3 promoted direct sulfenylation of indoles with disulfides. The method is applicable to a wide range of indoles containing different functional groups furnishing good to excellent yields. This synthetic strategy features environmental friendliness, easy operation, and mild reaction conditions. © 2013 The Royal Society of Chemistry.

Zhu D.-C.,China University of Geosciences | Zhao Z.-D.,China University of Geosciences | Niu Y.,Lanzhou University | Niu Y.,Durham University | And 4 more authors.
Gondwana Research | Year: 2013

Different hypotheses have been proposed for the origin and pre-Cenozoic evolution of the Tibetan Plateau as a result of several collision events between a series of Gondwana-derived terranes (e.g., Qiangtang, Lhasa and India) and Asian continent since the early Paleozoic. This paper reviews and reevaluates these hypotheses in light of new data from Tibet including (1) the distribution of major tectonic boundaries and suture zones, (2) basement rocks and their sedimentary covers, (3) magmatic suites, and (4) detrital zircon constraints from Paleozoic metasedimentary rocks. The Western Qiangtang, Amdo, and Tethyan Himalaya terranes have the Indian Gondwana origin, whereas the Lhasa Terrane shows an Australian Gondwana affinity. The Cambrian magmatic record in the Lhasa Terrane resulted from the subduction of the proto-Tethyan Ocean lithosphere beneath the Australian Gondwana. The newly identified late Devonian granitoids in the southern margin of the Lhasa Terrane may represent an extensional magmatic event associated with its rifting, which ultimately resulted in the opening of the Songdo Tethyan Ocean. The Lhasa-northern Australia collision at ~ 263. Ma was likely responsible for the initiation of a southward-dipping subduction of the Bangong-Nujiang Tethyan Oceanic lithosphere. The Yarlung-Zangbo Tethyan Ocean opened as a back-arc basin in the late Triassic, leading to the separation of the Lhasa Terrane from northern Australia. The subsequent northward subduction of the Yarlung-Zangbo Tethyan Ocean lithosphere beneath the Lhasa Terrane may have been triggered by the Qiangtang-Lhasa collision in the earliest Cretaceous. The mafic dike swarms (ca. 284. Ma) in the Western Qiangtang originated from the Panjal plume activity that resulted in continental rifting and its separation from the northern Indian continent. The subsequent collision of the Western Qiangtang with the Eastern Qiangtang in the middle Triassic was followed by slab breakoff that led to the exhumation of the Qiangtang metamorphic rocks. This collision may have caused the northward subduction initiation of the Bangong-Nujiang Ocean lithosphere beneath the Western Qiangtang. Collision-related coeval igneous rocks occurring on both sides of the suture zone and the within-plate basalt affinity of associated mafic lithologies suggest slab breakoff-induced magmatism in a continent-continent collision zone. This zone may be the site of net continental crust growth, as exemplified by the Tibetan Plateau. © 2012 International Association for Gondwana Research.

Song S.,Peking University | Niu Y.,Lanzhou University | Niu Y.,Durham University | Su L.,China University of Geosciences | Xia X.,Peking University
Gondwana Research | Year: 2013

The Qilian Orogen at the northern margin of the Tibetan Plateau is a type suture zone that recorded a complete history from continental breakup to ocean basin evolution, and to the ultimate continental collision in the time period from the Neoproterozoic to the Paleozoic. The Qilian Ocean, often interpreted as representing the "Proto-Tethyan Ocean", may actually be an eastern branch of the worldwide "Iapetus Ocean" between the two continents of Baltica and Laurentia, opened at ≥. 710. Ma as a consequence of breakup of supercontinent Rodinia. Initiation of the subduction in the Qilian Ocean probably occurred at ~ 520. Ma with the development of an Andean-type active continental margin represented by infant arc magmatism of ~ 517-490 Ma. In the beginning of Ordovician (~ 490. Ma), part of the active margin was split from the continental Alashan block and the Andean-type active margin had thus evolved to western Pacific-type trench-arc-back-arc system represented by the MORB-like crust (i.e., SSZ-type ophiolite belt) formed in a back-arc basin setting in the time period of ~ 490-445 Ma. During this time, the subducting oceanic lithosphere underwent LT-HP metamorphism along a cold geotherm of ~ 6-7. °C/km. The Qilian Ocean was closed at the end of the Ordovician (~ 445. Ma). Continental blocks started to collide and the northern edge of the Qilian-Qaidam block was underthrust/dragged beneath the Alashan block by the downgoing oceanic lithosphere to depths of ~ 100-200. km at about 435-420. Ma. Intensive orogenic activities occurred in the late Silurian and early Devonian in response to the exhumation of the subducted crustal materials. Briefly, the Qilian Orogen is conceptually a type example of the workings of plate tectonics from continental breakup to the development and evolution of an ocean basin, to the initiation of oceanic subduction and formation of arc and back-arc system, and to the final continental collision/subduction and exhumation. © 2012 International Association for Gondwana Research.

Yang Y.,Zhejiang University | Yao J.,Zhejiang University | Zhang Y.,Zhejiang University | Zhang Y.,Lanzhou University
Organic Letters | Year: 2013

A novel copper-mediated annulation of alkyl ketones with α,β-unsaturated carboxylic acids has been accomplished. This reaction provides a facile and regio-defined method for the synthesis of 2,3,5-trisubstituted furans from simple chemical reagents. © 2013 American Chemical Society.

Zhang F.,Lanzhou University
Chinese Physics Letters | Year: 2016

Within the framework of a semiclassical BoltzmannUehlingUhlenbeck (BUU) transport model, the high momentum tail (HMT) effects of nucleon momentum distribution in the nucleus on the nucleon collective flows are studied in semicentral Au+Au collisions. The HMT due to the isospin-dependent short-range correlations causes a smaller value of the collective flows. We find that the HMT effects on the nucleon collective flows are remarkable at beam energy of 300MeV/nucleon and become weak as the incident beam energy increases. The results indicate that for the collective flow studies at intermediate energies, the HMT of nucleon momentum distribution in nucleus should be taken into account in transport models. © 2016 Chinese Physical Society and IOP Publishing Ltd.

Hu M.,Hunan University | Song R.-J.,Hunan University | Li J.-H.,Hunan University | Li J.-H.,Lanzhou University
Angewandte Chemie - International Edition | Year: 2015

A new metal-free radical 5-exo-dig cyclization of phenol-linked 1,6-enynes with O2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), and tBuONO is described. With this general method, carbonylated benzofurans can be accessed through incorporation of two oxygen atoms into the product from O2 and TEMPO through dioxygen activation and oxidative cleavage of the N-O bond, respectively. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

He C.-L.,Anhui University of Science and Technology | Liu R.,Anhui University of Science and Technology | Li D.-D.,Anhui University of Science and Technology | Zhu S.-E.,Anhui University of Science and Technology | And 2 more authors.
Organic Letters | Year: 2013

The silver carbonate promoted reaction of [60]fullerene with (Z)-N-arylbenzamidines afforded the unprecedented C60-fused imidazoline derivatives in high yields. Substrates with both electron-donating and -withdrawing groups on aromatic rings could be employed. In addition, the electrochemistry and further selective functionalization of the obtained C 60-fused imidazolines were investigated. © 2013 American Chemical Society.

Zhang Y.-A.,Peking University | Liu Q.,Peking University | Wang C.,Peking University | Jia Y.,Peking University | Jia Y.,Lanzhou University
Organic Letters | Year: 2013

A concise total synthesis of rugulovasine A is achieved by using Uhle's ketone derivative as the key intermediate, which was synthesized by intramolecular cyclization via metal-halogen exchange. Two different routes to construct a spirocyclic butyrolactone subunit involving a Ru-catalyzed cyclocarbonylation and a special Ru-catalyzed double bond rearrangement were studied. © 2013 American Chemical Society.

Fan G.-P.,Anhui University of Science and Technology | Liu Z.,Anhui University of Science and Technology | Wang G.-W.,Anhui University of Science and Technology | Wang G.-W.,Lanzhou University
Green Chemistry | Year: 2013

Solvent-free reactions of allylic alcohols with various nucleophiles including indoles, sulfamides and anilines were efficiently achieved in the presence of 20% ZnBr2 under high-speed vibration milling conditions, and the products were obtained in good to excellent yields with the formation of water as the only byproduct. © 2013 The Royal Society of Chemistry.

Liu P.,Lanzhou University
Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases | Year: 2012

To investigate the use of multislice spiral CT (MSCT) in the diagnosis of pulmonary arterial hypertension (PAH) in patients with chronic obstructive pulmonary disease (COPD). The diameters and areas of the pulmonary artery were measured in 81 cases with COPD and 100 normal adults from January to November 2011. The ratios of the diameters of the main pulmonary artery (MPA) to ascending aorta (AA), descending aorta (DA), trachea, thoracic vertebra (ThV) were also calculated. Data analysis used the t test of the 2 samples compared, multi-rate compared by χ(2) test. There were significant differences in the measured parameters between the COPD group and the control group. The differences were also significant among groups of COPD patients aged < 40 y, 40 - 60 y, > 60 y, and the control group, among patients with different stages of COPD (stage I, II, III, IV) and the control group, and among patients with sPAP > 50 mm Hg (1 mm Hg = 0.133 kPa), sPAP ≤ 50 mm Hg and the control group. There were positive correlations between sPAP and the measured indexes such as MPA [(3.14 ± 0.63) cm] of pulmonary artery in COPD. There were negative correlations between FEV(1)% and some of the measured indexes such as MPA/T(d) (1.81 ± 0.48). Multi-indicators was no significant difference (χ(2) = 17.76, P > 0.05). MSCT is very useful in diagnosis of PAH in COPD. The diameter ratio of MPA to trachea, the area of MPA, and the diameter ratio of MPA to ThV can be used as diagnostic criteria for evaluation of PAH in COPD.

Che J.,Nanchang Institute of Technology | Wang J.,Lanzhou University | Tang Y.,Nanchang Institute of Technology
Applied Soft Computing Journal | Year: 2012

This paper presents an optimal training subset for support vector regression (SVR) under deregulated power, which has a distinct advantage over SVR based on the full training set, since it solves the problem of large sample memory complexity O(N 2) and prevents over-fitting during unbalanced data regression. To compute the proposed optimal training subset, an approximation convexity optimization framework is constructed through coupling a penalty term for the size of the optimal training subset to the mean absolute percentage error (MAPE) for the full training set prediction. Furthermore, a special method for finding the approximate solution of the optimization goal function is introduced, which enables us to extract maximum information from the full training set and increases the overall prediction accuracy. The applicability and superiority of the presented algorithm are shown by the half-hourly electric load data (48 data points per day) experiments in New South Wales under three different sample sizes. Especially, the benefit of the developed methods for large data sets is demonstrated by the significantly less CPU running time. © 2012 Elsevier B.V. All rights reserved.

Zhao Z.-G.,Lanzhou University | Huang S.-Q.,Wuhan University
International Journal of Plant Sciences | Year: 2013

Premise of research. In flowers that are specialized, floral traits often differentiate in association with pollinator shifts. However, in species of generalized pollination, the role of pollinators in local population differentiation of floral traits is difficult to test. A crucial line of evidence is to contrast the direction and strength of pollinator selection among populations. Methodology. Variation in floral traits and pollinator assemblages was investigated in two populations of a generalist-pollinated herb, Trollius ranunculoides (Ranunculaceae), to detect the potential role of pollinators in floral differentiation. Pivotal results. The alpine population was visited more by flies, and the subalpine population was visited more by bees. Flower manipulations suggested that large flowers were more attractive to both bees and flies, while more petals were favored only by nectar-feeding flies. Compared to the subalpine population, plants in the alpine population had more petals per flower but smaller flowers where flies were predominant pollinators. Flower differences appeared to be genetically maintained in a common garden. Phenotypic selection analysis indicated stronger selection on petal number in the alpine population and oppositely more intense selection on flower diameter in the subalpine population, in accordance with the preferences of local pollinator assemblages. Conclusions. Heritability in floral traits, differences in local pollinator assemblages, and corresponding differences in phenotypic selection are together consistent with the view of pollinator-mediated selection on floral differentiation in T. ranunculoides. © 2013 by The University of Chicago. All rights reserved.

Niu Y.,Lanzhou University | Niu Y.,Durham University
RSC Advances | Year: 2012

Zr-Hf and Nb-Ta are two elemental twins, each of which has the same valence (i.e. 5 + for Nb and Ta, and 4 + for Zr and Hf) and same ionic size at a given coordination number (e.g. R Nb/R Ta = 1.000 and R Zr/R Hf = 1.006 to ∼1.026 for coordination numbers of 6, 7, 8 and 12). As a result, it has been the view that Zr does not fractionate from Hf and Nb does not fractionate from Ta in the formation of minerals and in all Earth processes. Recent studies, however, have shown that this traditional view is in error. Up to 2 orders of magnitude fractionations have been observed in rocks from the world ocean floor and also in the seawater on various scales. I discuss some possible processes that may help explain such large fractionations, but further work is needed to test the validity of these interpretations. Perspectives from the chemistry community are in compelling need to help address this basic problem of scientific significance in understanding the chemical differentiation of our planet. © 2012 The Royal Society of Chemistry.

Zhang X.,Northwest University, China | Cao Y.,Northwest University, China | Yu S.,Northwest University, China | Yang F.,Northwest University, China | Xi P.,Lanzhou University
Biosensors and Bioelectronics | Year: 2013

Carbon-supported PdNi nanoparticles (PdNi/C) were synthesized using a novel synthetic route, and characterized by transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The overall metallic content (Pd+Ni) was 10% (w/w) and uniformly distributed in the carbon black (90%) matrix. The electrocatalytic performance of the PdNi/C modified glassy carbon electrode (GCE) was investigated for ascorbic acid (AA) oxidation, and showed better catalytic activity than an equal amount of commercially available palladium carbon catalyst. The oxidation potential of AA was negatively shifted to -0.05V. The biosensor tolerated a wide linear concentration range for AA, from 1.0×10-5M to 1.8×10-3M (R=0.9973), with a detection limit of 0.5μM (S/N=3). Our results demonstrate that PdNi/C nanomaterials have excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. These qualities make the Pd-based bimetallic catalysts promising candidates for amperometric sensing. © 2013 Elsevier B.V.

Cheng H.-Y.,Academia Sinica, Taiwan | Yu F.-S.,Lanzhou University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

The empirical observation of near degeneracy of scalar mesons above 1 GeV, namely, the mass of the strange-flavor scalar meson is similar to that of the nonstrange one, is at variance with the naive expectation of the quark model. Qualitatively, the approximate mass degeneracy can be understood as a consequence of self-energy effects due to strong coupled channels which will push down the mass of the heavy scalar meson in the strange sector more than that in the nonstrange partner. However, it works in the conventional model without heavy quark expansion, but not in the approach of heavy meson chiral perturbation theory as mass degeneracy and the physical masses of Ds0* and D0* cannot be accounted for simultaneously. In the heavy quark limit, near mass degeneracy observed in the scalar charm sector will imply the same phenomenon in the B system. We have the prediction MB0*≈MBs0*≈ 5715MeV+δΔS based on heavy quark symmetry and the leading-order QCD correction, where δΔS arises from 1/mQ corrections. A crude estimate indicates that δΔS is of order -35MeV or less. We stress that the closeness of Bs0* and B0* masses implied by heavy quark symmetry is not spoiled by 1/mQ or QCD corrections. The mass-shift effect on K0*(1430) is discussed. © 2014 American Physical Society.

The Yanqi Basin in Xinjiang Province is an important agricultural area with a high population density. The extensive agricultural activities in the Yanqi Basin started in the 1950s with flood irrigation techniques. Since then, the groundwater table was raised because of the absence of an efficient drainage system. This obstacle is a crucial factor that restricts sustainable socioeconomic development. Hydrochemical investigations were conducted in the Yanqi Basin, Northwestern China, to determine the chemical composition of groundwater. Sixty groundwater samples were collected from different wells to monitor the water chemistry of various ions. The results of the chemical analysis indicate that the groundwater in the area is generally neutral to slightly alkaline and predominantly contains Na+ and Ca2+ cations as well as HCO3 - and SO4 2+ anions. High positive correlations between HCO3 --Mg 2+ + Ca2+, SO 4 2--Mg2+, SO4 2--Na+ + K+, and Cl --Na+ + K+ were obtained. The total dissolved solids (TDS) mainly depend on the concentration of major ions such as HCO 3 -, SO4 2-, Cl-, Ca 2+, Mg2+, and Na+ + K+. The dominant hydrochemical facies for groundwater are Ca2+-Mg2+- HCO3 -, Mg2+-Ca2+-SO4 2--Cl-, Na+-K+-Cl --SO4 2-, and Na+-K +-Mg2+-Cl--HCO3 - types. The hydrochemical processes are the main factors that determine the water quality of the groundwater system. These processes include silicate mineral weathering, dissolution, ion exchange, and, to a lesser extent, evaporation, which seem to be more pronounced downgradient of the flow system. The saturation index (SI), which is calculated according to the ionic ratio plot, indicates that the gypsum-halite dissolution reactions occur during a certain degree of rock weathering. SI also indicates that evaporation is the dominant factor that determines the major ionic composition in the study area. The assessment results of the water samples using various methods indicate that the groundwater in the study area is generally hard, fresh to brackish, high to very high saline, and low alkaline in nature. The high total hardness and TDS of the groundwater in several places indicate the unsuitability of the groundwater for drinking and irrigation. These areas require particular attention, particularly in the construction of adequate drainage as well as in the introduction of an alternative salt tolerance cropping. © 2013 Springer Science+Business Media Dordrecht.

Wang J.,Dongbei University of Finance and Economics | Xiong S.,Lanzhou University
Energy | Year: 2014

Wind energy is regarded as a worldwide renewable and alternative energy that can relieve the energy shortage, reduce environmental pollution, and provide a significant potential economic benefit. In this paper, a hybrid method is developed to properly and efficiently forecast the daily wind speed in Hainan Province, China. The proposed hybrid forecasting model consists of outlier detection and a bivariate fuzzy time series, which provides a more powerful forecasting capacity of daily wind speed than that of traditional single forecasting models. To verify the developed approach, daily wind speed data from January 2008 to December 2012 in Hainan Province, China, are used for model construction and testing. The results show that the developed hybrid forecasting model achieves high forecasting accuracy and is suitable for forecasting the wind energy of China's large wind farms. © 2014 Elsevier Ltd.

Lin L.,Sichuan University | Kuang Y.,Sichuan University | Liu X.,Sichuan University | Feng X.,Sichuan University | Feng X.,Lanzhou University
Organic Letters | Year: 2011

A highly diastereo- and enantioselective hetero-Diels-Alder (HDA) reaction of a Brassard-type diene with aliphatic aldehydes has been developed. The chiral N,N′-dioxide L2/In(OTf) 3 complex was efficient toward the obtention of the corresponding β-methoxy-γ-methyl α,β-unsaturated δ-lactones in good yields (up to 86%) as well as dr and ee values (up to 97:3 cis/trans and 94% ee). In addition, the product 4a could be easily transformed into the methyl-protected epi-prelactone B by hydrogenation. © 2011 American Chemical Society.

He J.,CAS Lanzhou Institute of Modern Physics | He J.,Lanzhou University | He J.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

In this work the BB¯∗/DD¯∗ system is studied in the Bethe-Salpeter approach with quasipotential approximation. In our calculation both direct and cross diagrams are included in the one-boson-exchange potential. The numerical results indicate the existence of an isoscalar bound state DD¯∗ with JPC=1++, which may be related to the X(3872). In the isovector sector, no bound state is produced from the interactions of DD¯∗ and BB¯∗, which suggests the molecular state explanations for Zb(10610) and Zc(3900) are excluded. © 2014 American Physical Society.

Song H.,Lanzhou University
Nonlinear Analysis: Real World Applications | Year: 2015

Abstract In this paper, we consider the nonlinear viscoelastic equation: (Formula presented.), with initial conditions and Dirichlet boundary conditions. For nonincreasing positive functions g, we show the finite time blow up of some solutions whose initial data have arbitrarily high initial energy. © 2015 Elsevier Ltd.

Wu Z.-X.,Lanzhou University | Yang H.-X.,Fuzhou University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

We study the evolution of cooperation in the evolutionary spatial prisoner's dilemma game (PDG) and snowdrift game (SG), within which a fraction α of the payoffs of each player gained from direct game interactions is shared equally by the immediate neighbors. The magnitude of the parameter α therefore characterizes the degree of the relatedness among the neighboring players. By means of extensive Monte Carlo simulations as well as an extended mean-field approximation method, we trace the frequency of cooperation in the stationary state. We find that plugging into relatedness can significantly promote the evolution of cooperation in the context of both studied games. Unexpectedly, cooperation can be more readily established in the spatial PDG than that in the spatial SG, given that the degree of relatedness and the cost-to-benefit ratio of mutual cooperation are properly formulated. The relevance of our model with the stakeholder theory is also briefly discussed. © 2014 American Physical Society.

Xu A.,Lanzhou University | Wang J.,Henan Normal University | Wang H.,Henan Normal University
Green Chemistry | Year: 2010

Cellulose is the most abundant biorenewable and biodegradable resource on the earth. However, the extent of its application is limited due to its inefficient dissolution in solvents. Thus, the development of new cellulose solvents continues to be an active area of investigation. In this work, a series of ionic liquids (ILs) have been synthesized by coupling the 1-N-butyl-3-methylimidazolium cation [C4mim]+ with the Brønsted basic anions [CH3COO]-, [HSCH 2COO]-, [HCOO]-, [(C6H 5]COO]-, [H2NCH2COO]-, [HOCH2COO]-, [CH3CHOHCOO]- and [N(CN)2]-. The solubilities of microcrystalline cellulose (MCC) in these ionic liquids were determined as a function of temperature. The effect of the anion structure on the solubility of cellulose has been estimated, and investigated by 1H NMR and a solvatochromic UV/vis probe. It was found that the solubility of cellulose increases almost linearly with increasing hydrogen bond accepting ability of anions in the ionic liquids. At the same time, novel [C4mim][CH3COO]/lithium salt (LiCl, LiBr, LiAc, LiNO3, or LiClO4) solvent systems have been developed by adding 1.0 wt% of lithium salt into [C4mim][CH 3COO]. It was shown that the addition of lithium salts significantly increased the solubility of the cellulose. This observation was studied by 13C NMR spectra, and the results suggested that the enhanced solubility of cellulose originated from the disruption of the intermolecular hydrogen bond, O(6)H⋯O(3) owing to the interaction of Li+ with the hydroxyl oxygen O(3) of cellulose. Furthermore, the cellulose materials regenerated from the ionic liquids were characterized by scanning electron micrograph, thermogravimetric analysis and Fourier transform infrared spectroscopy, and the degree of polymerization of the original and regenerated cellulose materials was also determined. Good thermal stability was found for the regenerated cellulose. It is expected that the above information is useful for the design of novel ionic liquids and ionic liquid-based solvent systems for cellulose. © 2010 The Royal Society of Chemistry.

Qiu Q.-S.,Lanzhou University
Plant Signaling and Behavior | Year: 2016

ABSTRACT: AtNHX5 and AtNHX6, endosomal Na+,K+/H+ antiporters in Arabidopsis, are localized in the Golgi, trans-Golgi network, and prevacuolear compartment. It becomes evident that AtNHX5 and AtNHX6 play an important role in protein transport toward the vacuole. Studies have shown that AtNHX5 and AtNHX6 regulate the transport of seed storage proteins as well as the biogenesis of the protein storage vacuoles. Three distinct mechanisms have been revealed for the roles of AtNHX5 and AtNHX6 in protein transport. AtNHX5 and AtNHX6 control: (i) the binding of VSR to its cargoes; (ii) the recycling of VSRs; and (iii) subcellular localization of the SNARE complex. Moreover, it has been found that the endosomal pH homeostasis maintained by AtNHX5 and AtNHX6 is critical for the transport of seed storage proteins. Taken together, AtNHX5 and AtNHX6 regulate the trafficking of seed storage proteins into the vacuole; the H+ leak pathway conducted by AtNHX5 and AtNHX6 is critical for protein transport. © 2016 Taylor & Francis Group, LLC.

Ju L.,University of California at Berkeley | Geng B.,University of California at Berkeley | Geng B.,Lanzhou University | Horng J.,University of California at Berkeley | And 11 more authors.
Nature Nanotechnology | Year: 2011

Plasmons describe collective oscillations of electrons. They have a fundamental role in the dynamic responses of electron systems and form the basis of research into optical metamaterials. Plasmons of two-dimensional massless electrons, as present in graphene, show unusual behaviour that enables new tunable plasmonic metamaterials and, potentially, optoelectronic applications in the terahertz frequency range. Here we explore plasmon excitations in engineered graphene micro-ribbon arrays. We demonstrate that graphene plasmon resonances can be tuned over a broad terahertz frequency range by changing micro-ribbon width and in situ electrostatic doping. The ribbon width and carrier doping dependences of graphene plasmon frequency demonstrate power-law behaviour characteristic of two-dimensional massless Dirac electrons. The plasmon resonances have remarkably large oscillator strengths, resulting in prominent room-temperature optical absorption peaks. In comparison, plasmon absorption in a conventional two-dimensional electron gas was observed only at 4.2 K (refs 13, 14). The results represent a first look at light-plasmon coupling in graphene and point to potential graphene-based terahertz metamaterials. © 2011 Macmillan Publishers Limited. All rights reserved.

Pan X.J.,Lanzhou University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2012

To investigate the effect of Grape Seed Proanthocyanidins (GSPs) on enhancing the radiosensitivity of human hepatic carcinoma cell line HepG2, human cervical cancer cell line Hela and human leukemia cell line K562 for X-ray in vitro. The killing effect of GSPs combined with X-ray on cells was evaluated by SRB and clone formation assay. The GSPs had obvious cytotoxicity on three cell lines in a dose-dependent and time-dependent manners. However, inhibition rate of different cell line were quite different, the strongest one was human leukemia K562 cells and the others were weak. The sensitization ranges calculated by univariate analysis were 6.25-12.5 microg/mL for human leukemia K562 cells. Sensitization enhancement ratio was 1.94 using curve fitting method for K562 cells. GSPs can obviously enhance the radiosensitivity of cancer cells in vitro. The mechanism of sensitization effect may be related to the effects of GSPs on oxygen balance and cell cycle.

Li J.,Peking University | Lin S.,Peking University | Wang J.,Peking University | Jia S.,Peking University | And 5 more authors.
Journal of the American Chemical Society | Year: 2013

Palladium, a key transition metal in advancing modern organic synthesis, mediates diverse chemical conversions including many carbon-carbon bond formation reactions between organic compounds. However, expanding palladium chemistry for conjugation of biomolecules such as proteins, particularly within their native cellular context, is still in its infancy. Here we report the site-specific protein labeling inside pathogenic Gram-negative bacterial cells via a ligand-free palladium-mediated cross-coupling reaction. Two rationally designed pyrrolysine analogues bearing an aliphatic alkyne or an iodophenyl handle were first encoded in different enteric bacteria, which offered two facial handles for palladium-mediated Sonogashira coupling reaction on proteins within these pathogens. A GFP-based bioorthogonal reaction screening system was then developed, allowing evaluation of both the efficiency and the biocompatibilty of various palladium reagents in promoting protein-small molecule conjugation. The identified simple compound-Pd(NO3) 2 exhibited high efficiency and biocompatibility for site-specific labeling of proteins in vitro and inside living E. coli cells. This Pd-mediated protein coupling method was further utilized to label and visualize a Type-III Secretion (T3S) toxin-OspF in Shigella cells. Our strategy may be generally applicable for imaging and tracking various virulence proteins within Gram-negative bacterial pathogens. © 2013 American Chemical Society.

Shan D.,Peking University | Gao Y.,Peking University | Jia Y.,Peking University | Jia Y.,Lanzhou University
Angewandte Chemie - International Edition | Year: 2013

Core strength: A new and general strategy for the construction of 3,4-fused tricyclic indoles, which are the core structure of numerous natural products and bioactive molecules, has been developed. The method involves a one-step intramolecular Larock indolization and was successfully applied to the first total synthesis of fargesine. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang X.,Lanzhou University
Lin chuang er bi yan hou tou jing wai ke za zhi = Journal of clinical otorhinolaryngology, head, and neck surgery | Year: 2012

To assess the efficacy and adverse reaction of nasal packing materials Rapid Rhino and Merocel. We searched the database PubMed, EMBASE, Cochrane Library, CBM, CNKI, VIP and WANFANG database on line by computer, and traced the related references. Randomized controlled trials(RCTs) of rapid rhino and merocel as nasal packing materials were included. The quality of the included documents was evaluated by the criterion of Cochrane handbook 5.1. The cochrane collaboration's Revman 5.1 software was used for data analysis. Four RCTs involving 115 patients were identified. Meta-analyses showed that Rapid Rhino produced significantly lower pain and discomfort during insert of pack [MD = 1.37, 95% CI (0.13, 2.60), P < 0.05], whereas less pain and discomfort during removal of pack [MD = 2.88, 95% CI (2.34, 3.41), P < 0.01]. Rapid Rhino associated with a significantly slighter degree of fullness raised after insertion [MD = 1.15, 95% CI (0.75, 1.55), P < 0.01, and the same situation happened after 6 hours [MD = 1.15, 95% CI (0.75, 1.55), P < 0.01]. Rapid rhino caused to less reactionary bleeding when pack removal [MD = 0.26, 95% CI (0.12, 0.39), P < 0.01], rapid rhino was easier for the healthcare worker during insert and removal. There was no significant difference between two packs on the efficiency of hemostatic [OR = 1.00, 95% CI (0.38, 2.61), P > 0.05]. The application of Rapid Rhino caused less pain and fullness, leaded to slighter bleed than Merocel when insertion and removal. There was no significant difference between two packs on the efficiency of hemostatic when used for epistaxis or after routine nasal surgery.

Wang G.-W.,Anhui University of Science and Technology | Wang G.-W.,Lanzhou University | Gao J.,Anhui University of Science and Technology
Green Chemistry | Year: 2012

New solvent-free brominations of 1,3-dicarbonyl compounds, phenols, various alkenes including chalcones, azachalcones, 4-phenylbut-3-en-2-one, methyl cinnamate, styrene and 1,3-cyclohexadiene were efficiently achieved by employing sodium bromide and oxone under mechanical milling conditions. The brominated products were obtained in good to excellent yields. © 2012 The Royal Society of Chemistry.

Zeng P.Y.,Lanzhou University
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology | Year: 2012

The objective of this study was to explore the effect of astragalus polysaccharide (APS) on sensitivity of leukemic cell line HL-60 to NK cell cytotoxicity and its mechanism. The cytotoxicities of NK cells against HL-60 cells were analyzed by LDH releasing assay at different effect-to-target cell ratios (E:T) before and after treated with APS. The gene expression of MHC class I chain-related (MICA) in HL-60 cells before and after APS treatment was assayed with RT-PCR. Protein expression of MICA in HL-60 cells was assayed by flow cytometry before and after treated by APS. The results showed that after treated with APS 15 mg/ml for 48 h, the cytotoxicities of NK cells against HL-60 cells enhanced at different effect-to-target (P < 0.05), and the gene and protein expressions in MICA of HL-60 cells were up-regulated (P < 0.05). It is concluded that the APS can obviously up-regulate the expression of MICA in HL-60 cells, thus enhance sensitivity of HL-60 cells to cytotoxicity of NK cells.

Meng X.,Nankai University | Meng X.,CAS Institute of Theoretical Physics | Du X.,Nankai University | Du X.,Lanzhou University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

In the generalized Einstein-aether theories by taking a special form of the Lagrangian density of aether field, the possibility of Einstein-aether theory as an alternative to dark energy model is discussed in detail, that is, taking a special aether field as a dark energy candidate. We compute the joint statistic constraints on this special model's parameters by using the recent type Ia supernovae (SNe Ia) data, the Cosmic Microwave Background (CMB) shift parameter data, and the Baryonic Acoustic Oscillations (BAOs) data traced by the Sloan Digital Sky Survey (SDSS). Furthermore, we analyze other constrains from the Observational Hubble parameter Data (OHD). The comparison with the standard cosmological model (cosmological constant Λ Cold Dark Matter (ΛCDM) model) is clearly shown with new features; also we comment on an interesting relation between the coupling constant M in this model and the possible existence of a special accelerating scale in the MOdified Newtonian Dynamics (MOND) model initially given by Milgrom with the hope for interpreting the galaxy rotation curves without introducing mysterious dark matter. © 2012.

Jin R.R.,Lanzhou University
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology | Year: 2012

This study was purposed to investigate the effect of 3'-azido-2', 3'-dideoxythymidine (AZT)on the proliferation and telomerase activity of human acute myeloid leukemia cell line KG-1a. The effect of proliferation was detected by MTT assay after the KG-1a cell were stimulated for 24, 48 and 72 h with different concentrations of AZT; telomerase activity was detected with TRAP-PCR-ELISA assay; RT-PCR was used to detect telomerase hTERT mRNA expression. The results showed that the proliferation of KG-1a cells was inhibited in a time and concentration dependent manner after exposure to AZT for 24, 48 and 72 h; the KG-1a cells decreased in S phase and increased in G(2)/M phase with the increasing of the concentration of AZT; telomerase activity and hTERT-mRNA expression in the experimental groups decreased after treated with AZT, which was positively correlated with concentration of AZT. It is concluded that AZT inhibits KG-1a cell proliferation and induces apoptosis, which maybe related with its decreasing the telomerase activity and hTERT mRNA expression.

Weiner J.,Copenhagen University | Xiao S.,Lanzhou University
Theoretical Ecology | Year: 2012

We hypothesize that the continuum between generalist and specialist adaptations is an important general trade-off axis in the maintenance of local diversity, and we explore this idea with a simple model in which there are patch types to which species arrive as propagules and compete. Each patch type is defined by a competitive ranking of all species. A highly specialist species is the top competitor in one patch type but has a relatively low average ranking across different patch types, while a generalist species has a high average rank across patch types but is not the top competitor in any patch type. We use random dispersal and vary the fecundity of all species together to vary total propagule density and therefore recruitment limitation and density-dependent mortality. When fecundity is very high, each patch becomes occupied by its specialist species and generalists go extinct, so the number of species at equilibrium is equal to the number of patch types. If fecundity is very low, generalists dominate and specialists go extinct. There is a range of fecundity levels in which specialists, generalists, and intermediates coexist, and the number of species is substantially greater than the number of patch types. While coexistence of specialists and generalists has been considered a problem in evolutionary ecology, our results suggest to the contrary that this trade-off contributes to the maintenance of local diversity. © 2012 Springer Science+Business Media B.V.

Lin G.,Lanzhou University
Physica D: Nonlinear Phenomena | Year: 2012

This paper is concerned with the asymptotic spreading of a LotkaVolterra cooperative system. By using the theory of asymptotic spreading of nonautonomous equations, the asymptotic speeds of spreading of unknown functions formulated by a coupled system are estimated. Our results imply that the asymptotic spreading of one species can be significantly fastened by introducing a mutual species, which indicates the role of cooperation described by the coupled nonlinearities. © 2011 Elsevier B.V. All rights reserved.

Wang Y.-F.,University of Hong Kong | Feng Y.-Y.,East China University of Science and Technology | Ma X.,Lanzhou University | Gu J.-D.,University of Hong Kong
Applied Microbiology and Biotechnology | Year: 2013

Mangrove wetlands are an important ecosystem in tropical and subtropical regions, and the sediments may contain both oxic and anoxic zones. In this study, ammonia/ ammonium-oxidizing prokaryotes (AOPs) in yellow and black sediments with vegetation and non-vegetated sediments in a mangrove wetland of subtropical Hong Kong were investigated in winter and summer. The phylogenetic diversity of anammox bacterial 16S rRNA genes and archaeal and bacterial amoA genes (encoding ammonia monooxygenase alpha-subunit) were analyzed using PCR amplification and denaturing gradient gel electrophoresis to reveal their community structures. Quantitative PCR was also used to detect their gene abundances. The results showed that seasonality had little effect, but sediment type had a noticeable influence on the community structures and abundances of anammox bacteria. For ammoniaoxidizing archaea (AOA), seasonality had a small effect on their community structures, but a significant effect on their abundances: AOA amoA genes were significantly higher in winter than in summer. In winter, the vegetated yellow sediments had lower AOA amoA genes than the other types of sediments, but in summer, the vegetated yellow sediments had higher AOA amoA genes than the other types of sediments. Sediment type had no apparent effect on AOA community structures in winter. In summer, however, the vegetated yellow sediments showed obviously different AOA community structures from the other types of sediments. For ammonia-oxidizing bacteria (AOB), seasonality had a significant effect on their community structures and abundances: AOB amoA genes in winter were apparently higher than in summer, and AOB community structures were different between winter and summer. Sediment type had little effect on AOB community structures, but had a noticeable effect on the abundances: AOB amoA genes of the vegetated yellow sediments were obviously lower than the black ones in both seasons. This study has demonstrated that seasonality and sediment type affected community structures and abundances of AOPs differently in oxic and anoxic sediments of the mangrove wetland. © The Author(s) 2012. This article is published with open access at Springerlink.com.

Li T.,Lanzhou University
Brain : a journal of neurology | Year: 2013

Stroke induces rapid activation and expansion of microglia, but the main source of microgliosis is controversial. Here we investigated the formation of microgliosis and infiltration of circulating cells in a photothrombosis stroke model by taking advantage of parabiosis and two-photon microscopy. We found that a small population of blood-derived CX3CR1(GFP/+) cells infiltrated the cerebral parenchyma, but these cells did not proliferate and were phenotypically distinguishable from resident microglia. CX3CR1(GFP/+) infiltrating cells also displayed different kinetics from reactive microglia. The number of CX3CR1(GFP/+) infiltrating cells peaked on Day 5 after stroke and then decreased. The decline of these infiltrating cells was associated with an active apoptotic process. In contrast, reactive microglia were recruited to the ischaemic area continuously during the first week after stroke induction. Immunohistology and in vivo two-photon imaging revealed that cells involved in the process of microgliosis were mainly derived from proliferating resident microglia. Expansion of microglia exhibited a consistent pattern and our in vivo data demonstrated for the first time that microglia underwent active division in regions surrounding the ischaemic core. Together, these results indicated that CX3CR1(GFP/+) infiltrating cells and reactive microglia represented two distinct populations of cells with different functions and therapeutic potentials for the treatment of stroke.

Guo L.,Peking University | Zhang F.,Peking University | Hu W.,Peking University | Li L.,Peking University | And 2 more authors.