Showing papers by "South China University of Technology published in 2010"
••
TL;DR: In this article, the most recent advances in the synthesis and application of phosphors for white light-emitting diodes (pc-WLEDs) with emphasis specifically on: (a) principles to tune the excitation and emission spectra of the phosphors: prediction according to crystal field theory, and structural chemistry characteristics (e.g. covalence of chemical bonds, electronegativity, and polarization effects of element); (b) pc-W LEDs with phosphors excited by blue-LED chips: phosphor characteristics, structure, and activated ions
Abstract: Phosphor-converted white light-emitting diodes (pc-WLEDs) are emerging as an indispensable solid-state light source for the next generation lighting industry and display systems due to their unique properties including but not limited to energy savings, environment-friendliness, small volume, and long persistence. Until now, major challenges in pc-WLEDs have been to achieve high luminous efficacy, high chromatic stability, brilliant color-rending properties, and price competitiveness against fluorescent lamps, which rely critically on the phosphor properties. A comprehensive understanding of the nature and limitations of phosphors and the factors dominating the general trends in pc-WLEDs is of fundamental importance for advancing technological applications. This report aims to provide the most recent advances in the synthesis and application of phosphors for pc-WLEDs with emphasis specifically on: (a) principles to tune the excitation and emission spectra of phosphors: prediction according to crystal field theory, and structural chemistry characteristics (e.g. covalence of chemical bonds, electronegativity, and polarization effects of element); (b) pc-WLEDs with phosphors excited by blue-LED chips: phosphor characteristics, structure, and activated ions (i.e. Ce 3+ and Eu 2+ ), including YAG:Ce, other garnets, non-garnets, sulfides, and (oxy)nitrides; (c) pc-WLEDs with phosphors excited by near ultraviolet LED chips: single-phased white-emitting phosphors (e.g. Eu 2+ –Mn 2+ activated phosphors), red-green-blue phosphors, energy transfer, and mechanisms involved; and (d) new clues for designing novel high-performance phosphors for pc-WLEDs based on available LED chips. Emphasis shall also be placed on the relationships among crystal structure, luminescence properties, and device performances. In addition, applications, challenges and future advances of pc-WLEDs will be discussed.
1,860 citations
••
TL;DR: A population genomic survey has revealed a functionally important locus in genetic adaptation to high altitude, and the strongest signal of natural selection came from endothelial Per-Arnt-Sim domain protein 1 (EPAS1), a transcription factor involved in response to hypoxia.
Abstract: Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which represent strong candidates for altitude adaptation, were identified. The strongest signal of natural selection came from endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1), a transcription factor involved in response to hypoxia. One single-nucleotide polymorphism (SNP) at EPAS1 shows a 78% frequency difference between Tibetan and Han samples, representing the fastest allele frequency change observed at any human gene to date. This SNP's association with erythrocyte abundance supports the role of EPAS1 in adaptation to hypoxia. Thus, a population genomic survey has revealed a functionally important locus in genetic adaptation to high altitude.
1,325 citations
••
Chinese Academy of Sciences1, Shanghai Jiao Tong University2, Fudan University3, Kunming Institute of Zoology4, Shenzhen University5, Chengdu Research Base of Giant Panda Breeding6, Wellcome Trust7, University of Toronto8, University of California, Berkeley9, Southeast University10, University of Hong Kong11, Sun Yat-sen University12, University of Vienna13, Cardiff University14, Comenius University in Bratislava15, Sichuan University16, South China University of Technology17, University of Copenhagen18, University of Alberta19, University of Washington20
TL;DR: Using next-generation sequencing technology alone, a draft sequence of the giant panda genome is generated and assembled, indicating that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition.
Abstract: Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.
1,109 citations
••
TL;DR: An overview of the technologies in the production of biodiesel from microalgae, including the various modes of cultivation for theproduction of oil-rich microalgal biomass, as well as the subsequent downstream processing for biodiesel production is provided.
1,087 citations
••
TL;DR: In this paper, high quality graphene sheets were prepared from graphite powder through oxidation followed by rapid thermal expansion in nitrogen atmosphere, and the morphology and structure of the prepared graphene sheets are characterized by scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM).
970 citations
••
TL;DR: In this article, the strategies of utilizing surfactant-modified cathodes, hole-transporting buffer layers, and self-assembled monolayer (SAM)-modified anodes are highlighted.
Abstract: The field of organic electronics has been developed vastly in the past two decades due to its promise for low cost, lightweight, mechanical flexibility, versatility of chemical design and synthesis, and ease of processing. The performance and lifetime of these devices, such as organic light-emitting diodes (OLEDs), photovoltaics (OPVs), and field-effect transistors (OFETs), are critically dependent on the properties of both active materials and their interfaces. Interfacial properties can be controlled ranging from simple wettability or adhesion between different materials to direct modifications of the electronic structure of the materials. In this Feature Article, the strategies of utilizing surfactant-modified cathodes, hole-transporting buffer layers, and self-assembled monolayer (SAM)-modified anodes are highlighted. In addition to enabling the production of high-efficiency OLEDs, control of interfaces in both conventional and inverted polymer solar cells is shown to enhance their efficiency and stability; and the tailoring of source–drain electrode–semiconductor interfaces, dielectric–semiconductor interfaces, and ultrathin dielectrics is shown to allow for high-performance OFETs.
851 citations
••
TL;DR: Halloysite nanotubes (HNTs) are types of naturally occurring 1:1 clays with nanotubular structures and similar chemical composition to kaolin this article.
Abstract: Halloysite nanotubes (HNTs) are types of naturally occurring 1:1 clays with nanotubular structures and similar chemical composition to kaolin. Due to various characteristics such as nanoscale lumens, high length-to-diameter ratio, relatively low hydroxyl group density on the surface, etc., numerous exciting applications have been discovered for this unique, cheap and abundantly deposited clay. After briefly summarizing applications in controlled release, nanotemplating and sorption, we emphasize the applications of HNTs in the fabrication of polymer nanocomposites. The unique structures and performance of HNT-incorporated polymer nanocomposites processed by various routes are described. The results suggest that these nanocomposites exhibit remarkable performance such as reinforcing effects, enhanced flame retardancy and reduced thermal expansion. Accordingly, HNTs should be of interest in the area of polymer nanocomposites for structural and functional applications. Copyright © 2010 Society of Chemical Industry
615 citations
••
TL;DR: The CuO/MWCNTs electrode exhibits an enhanced electrocatalytic property, low working potential, high sensitivity, excellent selectivity, good stability, and fast amperometric sensing towards oxidation of glucose, thus is promising for the future development of nonenzymatic glucose sensors.
592 citations
••
554 citations
••
TL;DR: In this paper, the authors reviewed the recent progress made in the fields of UV-visible quantum cutting (QC) and the mechanism involved, including QC in single RE ion activated fluorides- and oxides-based phosphors, energy transfer and downconversion, QC in dual/ternary ions activated phosphors; and NIR QC in RE3+-Yb3+ (RE=Tb, Tm, and Pr) dual ions doped phosphors via cooperative energy transfer.
517 citations
••
TL;DR: The results indicate that the phenotypic status of ccRCC is characterized by a loss of normal renal function, downregulation of metabolic genes, and upregulation of many signal transduction genes in key pathways.
Abstract: Background
With the advent of second-generation sequencing, the expression of gene transcripts can be digitally measured with high accuracy. The purpose of this study was to systematically profile the expression of both mRNA and miRNA genes in clear cell renal cell carcinoma (ccRCC) using massively parallel sequencing technology.
Methodology
The expression of mRNAs and miRNAs were analyzed in tumor tissues and matched normal adjacent tissues obtained from 10 ccRCC patients without distant metastases. In a prevalence screen, some of the most interesting results were validated in a large cohort of ccRCC patients.
Principal Findings
A total of 404 miRNAs and 9,799 mRNAs were detected to be differentially expressed in the 10 ccRCC patients. We also identified 56 novel miRNA candidates in at least two samples. In addition to confirming that canonical cancer genes and miRNAs (including VEGFA, DUSP9 and ERBB4; miR-210, miR-184 and miR-206) play pivotal roles in ccRCC development, promising novel candidates (such as PNCK and miR-122) without previous annotation in ccRCC carcinogenesis were also discovered in this study. Pathways controlling cell fates (e.g., cell cycle and apoptosis pathways) and cell communication (e.g., focal adhesion and ECM-receptor interaction) were found to be significantly more likely to be disrupted in ccRCC. Additionally, the results of the prevalence screen revealed that the expression of a miRNA gene cluster located on Xq27.3 was consistently downregulated in at least 76.7% of ~50 ccRCC patients.
Conclusions
Our study provided a two-dimensional map of the mRNA and miRNA expression profiles of ccRCC using deep sequencing technology. Our results indicate that the phenotypic status of ccRCC is characterized by a loss of normal renal function, downregulation of metabolic genes, and upregulation of many signal transduction genes in key pathways. Furthermore, it can be concluded that downregulation of miRNA genes clustered on Xq27.3 is associated with ccRCC.
••
TL;DR: A new heterogeneous palladium catalyst was prepared by impregnation of palladium(II) nitrate on a metal-organic framework, MIL-101, giving highly dispersed palladium nanoparticles as discussed by the authors.
Abstract: A new heterogeneous palladium catalyst is prepared by impregnation of palladium(II) nitrate on a metal-organic framework, MIL-101, giving highly dispersed palladium nanoparticles.
••
TL;DR: In this paper, the authors provided an overview on basic operational principles and recent development of polymer solar cells and highlighted the possible routes for improvement in power conversion efficiency, stability, and the effects toward manufacturing of polysilicon solar cells.
••
TL;DR: In this critical review, the authors provide a brief review of recent developments in this field, including the materials design, functional principles, and their unique applications as interface modification layer in solution-processable multilayer optoelectronic devices.
Abstract: Water/alcohol soluble conjugated polymers (WSCPs) can be processed from water or other polar solvents, which offer good opportunities to avoid interfacial mixing upon fabrication of multilayer polymer optoelectronic devices by solution processing, and can dramatically improve charge injection from high work-function metal cathode resulting in greatly enhancement of the device performance. In this critical review, the authors provide a brief review of recent developments in this field, including the materials design, functional principles, and their unique applications as interface modification layer in solution-processable multilayer optoelectronic devices (135 references).
••
TL;DR: In this paper, the authors review the mechanisms and models of concentration polarization and inorganic fouling in pressure-driven membrane processes and evaluate the effects of operating parameters and membrane properties on the formation of inorganic scale at the membrane surface.
••
TL;DR: In this paper, the structure and morphology of the Fe 3 O 4 -graphene nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscope, and the electrochemical performances were evaluated in coin-type cells.
••
TL;DR: In this article, the authors considered the urban village as a community of interest for urbanized villagers, a migrant settlement with low-rent housing, and an urban self-organized grassroots unit, respectively related to ambiguous property rights, an informal rental market, and the vacuum of state regulation.
••
TL;DR: In this article, a simplified hydrodynamic equation, proposed by Ericksen and Leslie, was used to model the flow of nematic liquid crystals, and the existence of global (in time) weak solutions on a bounded smooth domain was established.
Abstract: This paper is concerned with a simplified hydrodynamic equation, proposed by Ericksen and Leslie, modeling the flow of nematic liquid crystals. In dimension two, we establish both interior and boundary regularity theorems for such a flow under smallness conditions. As a consequence, we establish the existence of global (in time) weak solutions on a bounded smooth domain in $${\mathbb{R}^2}$$
which are smooth everywhere with possible exceptions of finitely many singular times.
••
TL;DR: In this article, a self-assembled three-dimensional BiOI microspheres composed of nanoplatelets were synthesized at low temperature using ethanol-water mixed solvent as reaction media and NH3·H2O as pH adjustment.
Abstract: Self-assembled three-dimensional BiOI microspheres composed of nanoplatelets were synthesized at low temperature using ethanol–water mixed solvent as reaction media and NH3·H2O as pH adjustment. The as-prepared BiOI was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and nitrogen sorption. The possible formation mechanism for the architectures was discussed. It was found that mixed solvent and alkali play key roles in the formation of BiOI microspheres. The photocatalytic activity of the as-prepared sample was evaluated by degradation of phenol in aqueous solution under visible light irradiation. The BiOI microspheres show much higher photocatalytic activity than the random BiOI platelets. The total organic carbon measurement after the degradation process indicated that phenol was effectively mineralized over the BiOI microspheres. In addition, the BiOI microspheres are stable during the reaction and can be used repeatedly. The high catalytic performance of the BiOI microspheres comes from their narrow band gap, high surface area and high surface-to-volume ratio.
••
TL;DR: Analysis across the genome of patterns of DNA methylation reveals a rich landscape of allele-specific epigenetic modification and consequent effects on allele- specific gene expression.
Abstract: DNA methylation plays an important role in biological processes in human health and disease. Recent technological advances allow unbiased whole-genome DNA methylation (methylome) analysis to be carried out on human cells. Using whole-genome bisulfite sequencing at 24.7-fold coverage (12.3-fold per strand), we report a comprehensive (92.62%) methylome and analysis of the unique sequences in human peripheral blood mononuclear cells (PBMC) from the same Asian individual whose genome was deciphered in the YH project. PBMC constitute an important source for clinical blood tests world-wide. We found that 68.4% of CpG sites and 80% displayed allele-specific expression (ASE). These data demonstrate that ASM is a recurrent phenomenon and is highly correlated with ASE in human PBMCs. Together with recently reported similar studies, our study provides a comprehensive resource for future epigenomic research and confirms new sequencing technology as a paradigm for large-scale epigenomics studies.
••
TL;DR: Exome sequencing of 200 individuals from Denmark with targeted capture of 18,654 coding genes and sequence coverage of each individual exome at an average depth of 12-fold is reported, suggesting that deleterious substitutions are primarily recessive.
Abstract: Targeted capture combined with massively parallel exome sequencing is a promising approach to identify genetic variants implicated in human traits. We report exome sequencing of 200 individuals from Denmark with targeted capture of 18,654 coding genes and sequence coverage of each individual exome at an average depth of 12-fold. On average, about 95% of the target regions were covered by at least one read. We identified 121,870 SNPs in the sample population, including 53,081 coding SNPs (cSNPs). Using a statistical method for SNP calling and an estimation of allelic frequencies based on our population data, we derived the allele frequency spectrum of cSNPs with a minor allele frequency greater than 0.02. We identified a 1.8-fold excess of deleterious, non-syonomyous cSNPs over synonymous cSNPs in the low-frequency range (minor allele frequencies between 2% and 5%). This excess was more pronounced for X-linked SNPs, suggesting that deleterious substitutions are primarily recessive.
••
TL;DR: In this paper, the authors showed that a crystalline phase of CrMn1.5O4 was present in the Cr-MnOx catalysts, which contained the active species and showed the presence of Mn2+, Mn3+, Mn4+ and Cr2+, Cr3+, Cr5+ oxidation states.
••
TL;DR: The proposed consensus operator provides an alternative consensus model for group decision making and preserves the original preference information given by the decision makers as much as possible, and supports consensus process automatically, without moderator.
••
TL;DR: The results suggest that the genipin-cross-linked collagen/chitosan matrix may be a promising formulation for articular cartilage scaffolding.
Abstract: In this study, genipin-cross-linked collagen/chitosan biodegradable porous scaffolds were prepared for articular cartilage regeneration. The influence of chitosan amount and genipin concentration on the scaffolds physicochemical properties was evaluated. The morphologies of the scaffolds were characterized by scanning electron microscope (SEM) and cross-linking degree was investigated by ninhydrin assay. Additionally, the mechanical properties of the scaffolds were assessed under dynamic compression. To study the swelling ratio and the biostability of the collagen/chitosan scaffold, in vitro tests were also carried out by immersion of the scaffolds in PBS solution or digestion in collagenase, respectively. The results showed that the morphologies of the scaffolds underwent a fiber-like to a sheet-like structural transition by increasing chitosan amount. Genipin cross-linking remarkably changed the morphologies and pore sizes of the scaffolds when chitosan amount was less than 25%. Either by increasing the chitosan ratio or performing cross-linking treatment, the swelling ratio of the scaffolds can be tailored. The ninhydrin assay demonstrated that the addition of chitosan could obviously increase the cross-linking efficiency. The degradation studies indicated that genipin cross-linking can effectively enhance the biostability of the scaffolds. The biocompatibility of the scaffolds was evaluated by culturing rabbit chondrocytes in vitro. This study demonstrated that a good viability of the chondrocytes seeded on the scaffold was achieved. The SEM analysis has revealed that the chondrocytes adhered well to the surface of the scaffolds and contacted each other. These results suggest that the genipin-cross-linked collagen/chitosan matrix may be a promising formulation for articular cartilage scaffolding.
••
TL;DR: The mechanism of osmotic adjustment could help plants and algae to avoid ion toxicity and maintain water uptake in both stresses by accumulating large quantities of oSMolytes.
Abstract: The salinization and water deficit of soil are widespread environmental problems in limiting plant survival, growth, and productivity. However, some plants could adopt some strategies to resist sal...
••
TL;DR: In this paper, two fractional order proportional integral controllers are proposed and designed for a class of fractional-order systems, which can guarantee the desired control performance and the robustness of the designed controllers to the loop gain variations.
••
TL;DR: Among metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %.
Abstract: The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl 3 , FeCl 3 and CuCl 2 and a group IIIA metal chloride (AlCl 3 ), exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr
••
TL;DR: In this paper, the authors reported a highly efficient heterogeneous gold catalyst, which was deposited on a zeolite-type MOF (MIL-101) by a simple colloidal method with polyvinylpyrrolidone (PVP) as protecting agent using HAuCl4 as the Au precursor.
Abstract: The use of metal−organic frameworks (MOFs), an emerging class of porous materials, as supports for gold nanoparticles (NPs) may bring new opportunities in the development of highly active heterogeneous gold catalysts for a variety of catalytic reactions. Although currently a few examples of MOF-supported nanoparticulate Au have been reported, the preparation of an active Au NPs deposited MOF catalyst in solution is still a challenging research target. In this study, we report a highly efficient heterogeneous gold catalyst, which was deposited on a zeolite-type MOF (MIL-101) by a simple colloidal method with polyvinylpyrrolidone (PVP) as protecting agent using HAuCl4 as the Au precursor. The resulting Au/MIL-101 (CD/PVP) catalyst exhibited extremely high catalytic activities in liquid-phase aerobic oxidation of a wide range of alcohols, which could even efficiently catalyze the oxidation under ambient conditions in the absence of water or base. Moreover, the catalyst was easily recoverable and could be reu...
••
TL;DR: The finding of TGM6 as a novel causative gene of spinocerebellar ataxia illustrates whole-exome sequencing of affected individuals from one family as an effective and cost efficient method for mapping genes of rare Mendelian disorders and the use of linkage analysis and exome sequencing for further improving efficiency.
Abstract: Autosomal-dominant spinocerebellar ataxias constitute a large, heterogeneous group of progressive neurodegenerative diseases with multiple types. To date, classical genetic studies have revealed 31 distinct genetic forms of spinocerebellar ataxias and identified 19 causative genes. Traditional positional cloning strategies, however, have limitations for finding causative genes of rare Mendelian disorders. Here, we used a combined strategy of exome sequencing and linkage analysis to identify a novel spinocerebellar ataxia causative gene, TGM6. We sequenced the whole exome of four patients in a Chinese four-generation spinocerebellar ataxia family and identified a missense mutation, c.1550T-G transition (L517W), in exon 10 of TGM6. This change is at a highly conserved position, is predicted to have a functional impact, and completely cosegregated with the phenotype. The exome results were validated using linkage analysis. The mutation we identified using exome sequencing was located in the same region (20p13-12.2) as that identified by linkage analysis, which cross-validated TGM6 as the causative spinocerebellar ataxia gene in this family. We also showed that the causative gene could be mapped by a combined method of linkage analysis and sequencing of one sample from the family. We further confirmed our finding by identifying another missense mutation c.980A-G transition (D327G) in exon seven of TGM6 in an additional spinocerebellar ataxia family, which also cosegregated with the phenotype. Both mutations were absent in 500 normal unaffected individuals of matched geographical ancestry. The finding of TGM6 as a novel causative gene of spinocerebellar ataxia illustrates whole-exome sequencing of affected individuals from one family as an effective and cost efficient method for mapping genes of rare Mendelian disorders and the use of linkage analysis and exome sequencing for further improving efficiency.
••
TL;DR: In this paper, the degradation of a methylene blue solution using the dielectric barrier discharge (DBD) technique is proposed, and the effect of pH on the degradation rate is also investigated.