Showing papers by "Wuhan University published in 2009"
TL;DR: IDH1 appears to function as a tumor suppressor that, when mutationally inactivated, contributes to tumorigenesis in part through induction of the HIF-1 pathway.
Abstract: Heterozygous mutations in the gene encoding isocitrate dehydrogenase-1 (IDH1) occur in certain human brain tumors, but their mechanistic role in tumor development is unknown. We have shown that tumor-derived IDH1 mutations impair the enzyme's affinity for its substrate and dominantly inhibit wild-type IDH1 activity through the formation of catalytically inactive heterodimers. Forced expression of mutant IDH1 in cultured cells reduces formation of the enzyme product, alpha-ketoglutarate (alpha-KG), and increases the levels of hypoxia-inducible factor subunit HIF-1alpha, a transcription factor that facilitates tumor growth when oxygen is low and whose stability is regulated by alpha-KG. The rise in HIF-1alpha levels was reversible by an alpha-KG derivative. HIF-1alpha levels were higher in human gliomas harboring an IDH1 mutation than in tumors without a mutation. Thus, IDH1 appears to function as a tumor suppressor that, when mutationally inactivated, contributes to tumorigenesis in part through induction of the HIF-1 pathway.
1,078 citations
TL;DR: In this paper, the authors examined the long-run relationship between carbon emissions and energy consumption, income and foreign trade in the case of China by employing time series data of 1975-2005.
1,054 citations
TL;DR: In this article, the authors present a review of the recent developments in this field, and focus on two categories of PNIPAAm-based copolymer micelles as smart drug delivery systems.
635 citations
545 citations
TL;DR: This work cloned Bph14, a gene conferring resistance to Brown planthopper at seedling and maturity stages of the rice plant, using a map-base cloning approach and shows that it encodes a coiled-coil, nucleotide-binding, and leucine-rich repeat (CC-NB-LRR) protein that might function in recognition of the BPH insect invasion and activating the defense response.
Abstract: Planthoppers are highly destructive pests in crop production worldwide. Brown planthopper (BPH) causes the most serious damage of the rice crop globally among all rice pests. Growing resistant varieties is the most effective and environment-friendly strategy for protecting the crop from BPH. More than 19 BPH-resistance genes have been reported and used to various extents in rice breeding and production. In this study, we cloned Bph14, a gene conferring resistance to BPH at seedling and maturity stages of the rice plant, using a map-base cloning approach. We show that Bph14 encodes a coiled-coil, nucleotide-binding, and leucine-rich repeat (CC-NB-LRR) protein. Sequence comparison indicates that Bph14 carries a unique LRR domain that might function in recognition of the BPH insect invasion and activating the defense response. Bph14 is predominantly expressed in vascular bundles, the site of BPH feeding. Expression of Bph14 activates the salicylic acid signaling pathway and induces callose deposition in phloem cells and trypsin inhibitor production after planthopper infestation, thus reducing the feeding, growth rate, and longevity of the BPH insects. Our work provides insights into the molecular mechanisms of rice defense against insects and facilitates the development of resistant varieties to control this devastating insect.
438 citations
TL;DR: There is a new finding that there is a strong dependence of the activity of Pd toward the ORR on its morphology, and this finding furthers the understanding of PD catalysis and casts a new light on the relevant catalyst design criteria.
Abstract: Pd has been the focus of recent research for Pt-alternative catalysts for the oxygen reduction reaction (ORR). It has been found that upon appropriate modification of its electronic structure, the catalytic activity of Pd can become comparable to that of Pt. However, the structure-activity relationships of Pd catalysts have hitherto not been well studied or understood. In the present work, we report a new finding that there is a strong dependence of the activity of Pd toward the ORR on its morphology. By simply adjusting the precursor concentration in the electrochemical deposition of Pd, we are able to tailor the morphology of the deposited Pd from nanoparticles to nanorods. Surprisingly, the surface-specific activity of Pd nanorods (Pd-NRs) toward the ORR was found to be not only 10-fold higher than that of Pd nanoparticles (Pd-NPs), the conventional shape of electrocatalysts, but also comparable to that of Pt at operating potentials of fuel cell cathodes. The morphology-activity relationships of Pd-NRs were further studied through a combination of electrochemical experiments and density functional theory (DFT) calculations. As revealed by its characteristic profile for CO stripping, the morphology of Pd-NRs features the exposure of Pd(110) facets, which exhibit superior ORR activity. The underlying mechanism, indicated by DFT calculations, could be ascribed to the exceptionally weak interaction between an O adatom and a Pd(110) facet. This finding furthers our understanding of Pd catalysis and casts a new light on the relevant catalyst design criteria.
436 citations
TL;DR: A mechanism for PTB to modulate splice site competition to produce opposite functional consequences is suggested, which may be generally applicable to RNA-binding splicing factors to positively or negatively regulate alternative splicing in mammalian cells.
435 citations
TL;DR: The clinical application of berberine or huanglian as novel cancer therapeutic agents requires in vivo validations and further investigations of their anticancer mechanisms, as well as attracting scientists to pursue the potential anticancer effects and the mechanisms by using technologies of genomics, proteomics and other advanced approaches.
432 citations
TL;DR: Poly(anthraquinonyl sulfide) is synthesized and investigated as a novel organic cathode material for rechargeable lithium batteries, which shows excellent reversibility and cyclabilty and gives important insights into developing a new generation oforganic cathode materials with higher performance.
426 citations
TL;DR: It was proved that the fluorescence quenching of HSA by berberine is a result of the formation of berberin-HSA complex and the results of thermodynamic parameters DeltaG, DeltaH, and DeltaS at different temperatures indicate that the electrostatic interactions play a major role for berberines- HSA association.
404 citations
TL;DR: Findings indicate that miR-140 is involved in the chemoresistance by reduced cell proliferation through G1 and G2 phase arrest mediated in part through the suppression of HDAC4.
Abstract: In this study, high-throughput microRNA (miRNA) expression analysis revealed that the expression of miR-140 was associated with chemosensitivity in osteosarcoma tumor xenografts. Tumor cells ectopically transfected with miR-140 were more resistant to methotrexate and 5-fluorouracil (5-FU). Overexpression of miR-140 inhibited cell proliferation in both osteosarcoma U-2 OS (wt-p53) and colon cancer HCT 116 (wt-p53) cell lines, but less so in osteosarcoma MG63 (mut-p53) and colon cancer HCT 116 (null-p53) cell lines. miR-140 induced p53 and p21 expression accompanied with G(1) and G(2) phase arrest only in cell lines containing wild type of p53. Histone deacetylase 4 (HDAC4) was confirmed to be one of the important targets of miR-140. The expression of endogenous miR-140 was significantly elevated in CD133(+hi)CD44(+hi) colon cancer stem-like cells that exhibit slow proliferating rate and chemoresistance. Blocking endogenous miR-140 by locked nucleic acid-modified anti-miR partially sensitized resistant colon cancer stem-like cells to 5-FU treatment. Taken together, our findings indicate that miR-140 is involved in the chemoresistance by reduced cell proliferation through G(1) and G(2) phase arrest mediated in part through the suppression of HDAC4. miR-140 may be a candidate target to develop novel therapeutic strategy to overcome drug resistance.
TL;DR: A review on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized magnetic iron oxide NPs and their corresponding application is presented in this article.
Abstract: Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.
TL;DR: Mutational analysis in a replicon system showed that the N7-MTase activity was important for SARS virus replication/transcription and can thus be used as an attractive drug target to develop antivirals for control of coronaviruses including the deadly Sars virus.
Abstract: The N7-methylguanosine (m7G) cap is the defining structural feature of eukaryotic mRNAs. Most eukaryotic viruses that replicate in the cytoplasm, including coronaviruses, have evolved strategies to cap their RNAs. In this report, we used a yeast genetic system to functionally screen for the cap-forming enzymes encoded by severe acute respiratory syndrome (SARS) coronavirus and identified the nonstructural protein (nsp) 14 of SARS coronavirus as a (guanine-N7)-methyltransferase (N7-MTase) in vivo in yeast cells and in vitro using purified enzymes and RNA substrates. Interestingly, coronavirus nsp14 was previously characterized as a 3'-to-5' exoribonuclease, and by mutational analysis, we mapped the N7-MTase domain to the carboxy-terminal part of nsp14 that shows features conserved with cellular N7-MTase in structure-based sequence alignment. The exoribonuclease active site was dispensable but the exoribonuclease domain was required for N7-MTase activity. Such combination of the 2 functional domains in coronavirus nsp14 suggests that it may represent a novel form of RNA-processing enzymes. Mutational analysis in a replicon system showed that the N7-MTase activity was important for SARS virus replication/transcription and can thus be used as an attractive drug target to develop antivirals for control of coronaviruses including the deadly SARS virus. Furthermore, the observation that the N7-MTase of RNA life could function in lieu of that in DNA life provides interesting evolutionary insight and practical possibilities in antiviral drug screening.
TL;DR: It is shown that the E3 ubiquitin ligase RNF5 interacted with MITA in a viral-infection-dependent manner and found that virus-induced ubiquitination and degradation of MITA by R NF5 occurred at the mitochondria.
TL;DR: The crosslinked chitosan/nano- CdS (CS/n-CdS) composite catalyst prepared by simulating bio-mineralization process was extensively characterized by FT-IR spectra, XRD, SEM, TEM and TGA and found to follow a pseudo-first-order kinetics according to Langmuir-Hinshelwood (L-H) model.
TL;DR: Large-scale p-type CuO nanowire thin-film transistors are fabricated and they effectively demonstrate their enhanced performance, which makes it a promising candidate for a poisonous gas sensing nanodevice.
Abstract: We report the properties of a field effect transistor (FET) and a gas sensor based on CuO nanowires. CuO nanowire FETs exhibit p-type behavior. Large-scale p-type CuO nanowire thin-film transistors (104 devices in a 25?mm2 area) are fabricated and we effectively demonstrate their enhanced performance. Furthermore, CuO nanowire exhibits high and fast response to CO gas at 200??C, which makes it a promising candidate for a poisonous gas sensing nanodevice.
TL;DR: In this article, a series of pea hull fiber-derived nanowhisker (PHFNW-t) dispersions was prepared by hydrolyzing PEA hull fibres for different times (t) with sulfuric acid, and then blended with pea starch (PS) to fabricate bionanocomposite films.
TL;DR: These novel SNEDDS carriers appear to be useful for controlling the release rate of poorly water soluble drugs.
TL;DR: Electrochemical experiments show that the PtRu(1:1)-MWNT-IL/GCE has potential application in glucose detection and presents stronger electrocatalytic activity toward the glucose oxidation than other electrodes.
TL;DR: Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsor adaptation was the rate-limiting step, and results showed that cross-linked chitosan was favourable adsorbent.
21 Mar 2009
TL;DR: In this article, a quasi-Z-source inverter (qZSI) is proposed to achieve buck/boost, inversion and power conditioning in a single stage with improved reliability.
Abstract: This paper presents a quasi-Z-source inverter (qZSI) that is a new topology derived from the traditional Z-source inverter (ZSI). The qZSI inherits all the advantages of the ZSI, which can realize buck/boost, inversion and power conditioning in a single stage with improved reliability. In addition, the proposed qZSI has the unique advantages of lower component ratings and constant dc current from the source. All of the boost control methods that have been developed for the ZSI can be used by the qZSI. The qZSI features a wide range of voltage gain which is suitable for applications in photovoltaic (PV) systems, due to the fact that the PV cell's output varies widely with temperature and solar irradiation. Theoretical analysis of voltage boost, control methods and a system design guide for the qZSI in PV systems are investigated in this paper. A prototype has been built in the laboratory. Both simulations and experiments are presented to verify the proposed concept and theoretical analysis.
TL;DR: It is shown that the kappa of a packed bed of three-dimensional random networks of single and multiwall CNTs is smaller than that of thermally insulating amorphous polymers.
Abstract: Thermal conductivity ($\ensuremath{\kappa}$) of isolated carbon nanotubes (CNTs) is higher than the $\ensuremath{\kappa}$ of diamond; however, in this Letter we show that the $\ensuremath{\kappa}$ of a packed bed of three-dimensional random networks of single and multiwall CNTs is smaller than that of thermally insulating amorphous polymers. The thermoelectric power ($\ensuremath{\Sigma}$) of the random network of CNTs was also measured. The $\ensuremath{\Sigma}$ of a single wall nanotube network is very similar to that of isolated nanotubes and, in contrast with $\ensuremath{\kappa}$, $\ensuremath{\Sigma}$ shows a strong dependence on the tube diameter.
TL;DR: A highly efficient sorbent could efficiently adsorb the organic dyes from wastewater, and the used sorbents could be recovered completely, according to the results.
TL;DR: A risk-averse newsvendor with stochastic price-dependent demand with Conditional Value-at-Risk (CVaR) as the decision criterion is considered to investigate the optimal pricing and ordering decisions in such a setting.
Abstract: The classical risk-neutral newsvendor problem is to decide the order quantity that maximizes the one-period expected profit. In this note, we consider a risk-averse newsvendor with stochastic price-dependent demand. We adopt Conditional Value-at-Risk ( CVaR ), a risk measure commonly used in finance, as the decision criterion. The aim of our study is to investigate the optimal pricing and ordering decisions in such a setting. For both additive and multiplicative demand models, we provide sufficient conditions for the uniqueness and existence of the optimal policy. Comparative statics show the monotonicity properties and other characteristics of the optimal pricing and ordering decisions. We also compare our results with those of the newsvendor with a risk-neutral attitude and a general utility function.
TL;DR: Thermodynamic parameters, such as DeltaG degrees, DeltaH degrees, and DeltaS degrees were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm.
TL;DR: The interaction between malachite green and bovine serum albumin (BSA) under simulative physiological conditions was investigated by the methods of fluorescence spectroscopy, UV-vis absorption and circular dichroism (CD) spectroscope, which confirmed some micro-environmental and conformational changes of BSA molecules.
TL;DR: It can be concluded that application of stem cell transplantation technology to human disease therapy, especially research related on “embryonic stem cell” and “mesenchymal stemcell” is the orientation of all the stem cell research in the 21st century.
Abstract: In this study, we aim to evaluate the global scientific production of stem cell research for the past 16 years and provide insights into the characteristics of the stem cell research activities and identify patterns, tendencies, or regularities that may exist in the papers. Data are based on the online version of SCI, Web of Science from 1991 to 2006. Articles referring to stem cell were assessed by many aspects including exponential fitting the trend of publication outputs during 1991–2006, distribution of source title, author keyword, and keyword plus analysis. Based on the exponential fitting the yearly publicans of the last decade, it can also be calculated that, in 2,011, the number of scientific papers on the topic of stem-cell will be twice of the number of publications in 2006. Synthetically analyzing three kinds of keywords, it can be concluded that application of stem cell transplantation technology to human disease therapy, especially research related on “embryonic stem cell” and “mesenchymal stem cell” is the orientation of all the stem cell research in the 21st century. This new bibliometric method can help relevant researchers realize the panorama of global stem cell research, and establish the further research direction.
TL;DR: In this article, the effects of cellulose whisker content on the structure, morphology and properties of the nanocomposite films were characterized by SEM, XRD, FTIR, UV-vis spectroscopy, DMA, TG, tensile testing, and swelling experiment.
Abstract: Bio-based nanocomposite films were successfully developed using cellulose whiskers as the reinforcing phase and chitosan as the matrix. Cellulose whiskers, with the lengths of 400 ± 92 nm and diameters of 24 ± 7.5 nm on average, were prepared by hydrolyzing cotton linter with sulfuric acid solution. The effects of whisker content on the structure, morphology and properties of the nanocomposite films were characterized by SEM, XRD, FTIR, UV-vis spectroscopy, DMA, TG, tensile testing, and swelling experiment. The results indicated that the nanocomposites exhibited good miscibility, and strong interactions occurred between the whiskers and the matrix. With increasing whisker content from 0 to 15–20 wt %, the tensile strength of the composite films in dry and wet states increased from 85 to 120 MPa and 9.9 to 17.3 MPa, respectively. Furthermore, the nanocomposite films displayed excellent thermal stability and water resistance with the incorporation of cellulose whiskers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1069–1077, 2009
TL;DR: In this article, a SnO2nanorod array was constructed on large-area flexible metallic substrates (FeCoNi alloy and Ni foil) via a hydrothermal process for the first time and demonstrated as a highperformance anode material for lithium ion batteries.
Abstract: SnO2nanorod arrays have been prepared on large-area flexible metallic substrates (Fe–Co–Ni alloy and Ni foil) via a hydrothermal process for the first time and have been demonstrated as a high-performance anode material for lithium ion batteries Electrochemical behavior is found to depend crucially on the structural parameters of the array An array consisting of SnO2nanorods of average 60 nm in diameter and 670 nm in length delivers a reversible capacity of as high as 580 mAh g−1 after 100 cycles (at 01C) and shows excellent rate capability (350 mAh g−1 at the 5C rate) Structural disintegration and agglomeration were not observed for SnO2 arrays even after 50 cycles
TL;DR: It is demonstrated that an electrospun membrane incorporating nano-apatite (nAp) is strong, enhances bioactivity and supports osteoblast-like cell proliferation and differentiation.