280 research outputs found

    The Chinese accounting profession in the People's Republic: A preliminary understanding from an oral history perspective

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    While oral history still has a marginal role in accounting literature in general, it has not been applied at all in relation to the history of Chinese accounting. Within broader research on accounting change in China, this paper uses oral history to investigate patterns of the career of accountants in China. We interviewed 21 retired accountants, aging from 60 to 90 at the time of the interview, asking them to share their professional experience in open and unstructured talk. We reconstruct individual experiences, which provides insights into the working lives of our interviewees. Unlike previous studies that only focus on influential informants, we investigate Chinese accounting changes as they emerge from the collective memory of everyday accountants. Taking a pluralist perspective, we collect non-archival data to illustrate the education and common elements in accounting career development. Our approach takes a ‘view from below’, underlining the limitations of top-down perspectives in most of the literature on accounting change in China. The findings contribute to our understanding of accounting changes in China and their social and economic impacts on the profession while providing interesting implications for oral history in accounting in general

    Graphene re-knits its holes

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    Nano-holes, etched under an electron beam at room temperature in singlelayer graphene sheets as a result of their interaction with metalimpurities, are shown to heal spontaneously by filling up with either non-hexagon, graphene-like, or perfect hexagon 2D structures. Scanning transmission electron microscopy was employed to capture the healing process and study atom-by-atom the re-grown structure. A combination of these nano-scale etching and re-knitting processes could lead to new graphene tailoring approaches.Comment: 11 pages, 4 figure

    Silicon–Carbon Bond Inversions Driven by 60-keV Electrons in Graphene

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    We demonstrate that 60-keV electron irradiation drives the diffusion of threefold-coordinated Si dopants in graphene by one lattice site at a time. First principles simulations reveal that each step is caused by an electron impact on a C atom next to the dopant. Although the atomic motion happens below our experimental time resolution, stochastic analysis of 38 such lattice jumps reveals a probability for their occurrence in a good agreement with the simulations. Conversions from three- to fourfold coordinated dopant structures and the subsequent reverse process are significantly less likely than the direct bond inversion. Our results thus provide a model of nondestructive and atomically precise structural modification and detection for two-dimensional materials

    Probing defects and impurity-induced electronic structure changes in single and double-layer hexagonal boron nitride sheets with STEM-EELS

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    Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 - August 2, 201

    LRR-RLK family from two Citrus species: Genome-wide identification and evolutionary aspects

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    Background: Leucine-rich repeat receptor-like kinases (LRR-RLKs) represent the largest subfamily of plant RLKs. The functions of most LRR-RLKs have remained undiscovered, and a few that have been experimentally characterized have been shown to have important roles in growth and development as well as in defense responses. Although RLK subfamilies have been previously studied in many plants, no comprehensive study has been performed on this gene family in Citrus species, which have high economic importance and are frequent targets for emerging pathogens. In this study, we performed in silico analysis to identify and classify LRR-RLK homologues in the predicted proteomes of Citrus clementina (clementine) and Citrus sinensis (sweet orange). In addition, we used large-scale phylogenetic approaches to elucidate the evolutionary relationships of the LRR-RLKs and further narrowed the analysis to the LRR-XII group, which contains several previously described cell surface immune receptors. Results: We built integrative protein signature databases for Citrus clementina and Citrus sinensis using all predicted protein sequences obtained from whole genomes. A total of 300 and 297 proteins were identified as LRR-RLKs in C. clementina and C. sinensis, respectively. Maximum-likelihood phylogenetic trees were estimated using Arabidopsis LRR-RLK as a template and they allowed us to classify Citrus LRR- 34 RLKs into 16 groups. The LRR-XII group showed a remarkable expansion, containing approximately 150 paralogs encoded in each Citrus genome. Phylogenetic analysis also demonstrated the existence of two distinct LRR-XII clades, each one constituted mainly by RD and non-RD kinases. We identified 68 orthologous pairs from the C. clementina and C. sinensis LRR-XII genes. In addition, among the paralogs, we identified a subset of 78 and 62 clustered genes probably derived from tandem duplication events in the genomes of C. clementina and C. sinensis, respectively. Conclusions: This work provided the first comprehensive evolutionary analysis of the LRR-RLKs in Citrus. A large expansion of LRR-XII in Citrus genomes suggests that it might play a key role in adaptive responses in host-pathogen co-evolution, related to the perennial life cycle and domestication of the citrus crop species

    Role of Visible Light-Activated Photocatalyst on the Reduction of Anthrax Spore-Induced Mortality in Mice

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    BACKGROUND: Photocatalysis of titanium dioxide (TiO(2)) substrates is primarily induced by ultraviolet light irradiation. Anion-doped TiO(2) substrates were shown to exhibit photocatalytic activities under visible-light illumination, relative environmentally-friendly materials. Their anti-spore activity against Bacillus anthracis, however, remains to be investigated. We evaluated these visible-light activated photocatalysts on the reduction of anthrax spore-induced pathogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Standard plating method was used to determine the inactivation of anthrax spore by visible light-induced photocatalysis. Mouse models were further employed to investigate the suppressive effects of the photocatalysis on anthrax toxin- and spore-mediated mortality. We found that anti-spore activities of visible light illuminated nitrogen- or carbon-doped titania thin films significantly reduced viability of anthrax spores. Even though the spore-killing efficiency is only approximately 25%, our data indicate that spores from photocatalyzed groups but not untreated groups have a less survival rate after macrophage clearance. In addition, the photocatalysis could directly inactivate lethal toxin, the major virulence factor of B. anthracis. In agreement with these results, we found that the photocatalyzed spores have tenfold less potency to induce mortality in mice. These data suggest that the photocatalysis might injury the spores through inactivating spore components. CONCLUSION/SIGNIFICANCE: Photocatalysis induced injuries of the spores might be more important than direct killing of spores to reduce pathogenicity in the host

    Systematic generation of in vivo G protein-coupled receptor mutants in the rat

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    G-protein-coupled receptors (GPCRs) constitute a large family of cell surface receptors that are involved in a wide range of physiological and pathological processes, and are targets for many therapeutic interventions. However, genetic models in the rat, one of the most widely used model organisms in physiological and pharmacological research, are largely lacking. Here, we applied N-ethyl-N-nitrosourea (ENU)-driven target-selected mutagenesis to generate an in vivo GPCR mutant collection in the rat. A pre-selected panel of 250 human GPCR homologs was screened for mutations in 813 rats, resulting in the identification of 131 non-synonymous mutations. From these, seven novel potential rat gene knockouts were established as well as 45 lines carrying missense mutations in various genes associated with or involved in human diseases. We provide extensive in silico modeling results of the missense mutations and show experimental data, suggesting loss-of-function phenotypes for several models, including Mc4r and Lpar1. Taken together, the approach used resulted not only in a set of novel gene knockouts, but also in allelic series of more subtle amino acid variants, similar as commonly observed in human disease. The mutants presented here may greatly benefit studies to understand specific GPCR function and support the development of novel therapeutic strategies

    Generating and repairing genetically programmed DNA breaks during immunoglobulin class switch recombination

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    Adaptive immune responses require the generation of a diverse repertoire of immunoglobulins (Igs) that can recognize and neutralize a seemingly infinite number of antigens. V(D)J recombination creates the primary Ig repertoire, which subsequently is modified by somatic hypermutation (SHM) and class switch recombination (CSR). SHM promotes Ig affinity maturation whereas CSR alters the effector function of the Ig. Both SHM and CSR require activation-induced cytidine deaminase (AID) to produce dU:dG mismatches in the Ig locus that are transformed into untemplated mutations in variable coding segments during SHM or DNA double-strand breaks (DSBs) in switch regions during CSR. Within the Ig locus, DNA repair pathways are diverted from their canonical role in maintaining genomic integrity to permit AID-directed mutation and deletion of gene coding segments. Recently identified proteins, genes, and regulatory networks have provided new insights into the temporally and spatially coordinated molecular interactions that control the formation and repair of DSBs within the Ig locus. Unravelling the genetic program that allows B cells to selectively alter the Ig coding regions while protecting non-Ig genes from DNA damage advances our understanding of the molecular processes that maintain genomic integrity as well as humoral immunity
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