214 research outputs found
Developing Innovative Competences in an Emerging Business System: New Private Enterprises in Hangzhou’s Software Industry
What kind of innovative competences are credibly developed by private entrepreneurs in China’s transition economy? On the basis of original empirical fieldwork in 45 software enterprises in Hangzhou, Zhejiang Province, we propose a working theory of innovative competence development in an emerging private sector. Combining resource-based and institutional perspectives we argue that Chinese private enterprises in Hangzhou were able to develop unique innovative competences to overcome resource constraints and manage technical - and market risks while respecting the location and sector-specific constraints. The findings suggest that private software enterprises in Hangzhou developed five innovative competences: organizational integration, financial commitment, external knowledge transformation, reputation development and strategic flexibility. The analysis further allows to propose three implications: 1) These five competences form a ‘configuration’ or coherent set of competences in this particular institutional setting; 2) Technological – and institutional regimes shape the potential range of innovative competences firms credibly develop depending on the available resources of the firm; 3) Innovative competences can be functional equivalents of institutions in the absence of well-developed, mature formal institutions
Electrically Tunable Excitonic Light Emitting Diodes based on Monolayer WSe2 p-n Junctions
Light-emitting diodes are of importance for lighting, displays, optical
interconnects, logic and sensors. Hence the development of new systems that
allow improvements in their efficiency, spectral properties, compactness and
integrability could have significant ramifications. Monolayer transition metal
dichalcogenides have recently emerged as interesting candidates for
optoelectronic applications due to their unique optical properties.
Electroluminescence has already been observed from monolayer MoS2 devices.
However, the electroluminescence efficiency was low and the linewidth broad due
both to the poor optical quality of MoS2 and to ineffective contacts. Here, we
report electroluminescence from lateral p-n junctions in monolayer WSe2 induced
electrostatically using a thin boron nitride support as a dielectric layer with
multiple metal gates beneath. This structure allows effective injection of
electrons and holes, and combined with the high optical quality of WSe2 it
yields bright electroluminescence with 1000 times smaller injection current and
10 times smaller linewidth than in MoS2. Furthermore, by increasing the
injection bias we can tune the electroluminescence between regimes of
impurity-bound, charged, and neutral excitons. This system has the required
ingredients for new kinds of optoelectronic devices such as spin- and
valley-polarized light-emitting diodes, on-chip lasers, and two-dimensional
electro-optic modulators.Comment: 13 pages main text with 4 figures + 4 pages upplemental material
Study of Muscle Cell Dedifferentiation after Skeletal Muscle Injury of Mice with a Cre-Lox System
Background: Dedifferentiation of muscle cells in the tissue of mammals has yet to be observed. One of the challenges facing the study of skeletal muscle cell dedifferentiation is the availability of a reliable model that can confidentially distinguish differentiated cell populations of myotubes and non-fused mononuclear cells, including stem cells that can coexist within the population of cells being studied. Methodology/Principal Findings: In the current study, we created a Cre/Lox-β-galactosidase system, which can specifically tag differentiated multinuclear myotubes and myotube-generated mononuclear cells based on the activation of the marker gene, β-galactosidase. By using this system in an adult mouse model, we found that β-galactosidase positive mononuclear cells were generated from β-galactosidase positive multinuclear myofibers upon muscle injury. We also demonstrated that these mononuclear cells can develop into a variety of different muscle cell lineages, i.e., myoblasts, satellite cells, and muscle derived stem cells. Conclusions/Significance: These novel findings demonstrated, for the first time, that cellular dedifferentiation of skeletal muscle cells actually occurs in mammalian skeletal muscle following traumatic injury in vivo. © 2011 Mu et al
Human antibodies targeting cell surface antigens overexpressed by the hormone refractory metastatic prostate cancer cells: ICAM-1 is a tumor antigen that mediates prostate cancer cell invasion
Transition from hormone-sensitive to hormone-refractory metastatic tumor types poses a major challenge for prostate cancer treatment. Tumor antigens that are differentially expressed during this transition are likely to play important roles in imparting prostate cancer cells with the ability to grow in a hormone-deprived environment and to metastasize to distal sites such as the bone and thus, are likely targets for therapeutic intervention. To identify those molecules and particularly cell surface antigens that accompany this transition, we studied the changes in cell surface antigenic profiles between a hormone-sensitive prostate cancer line LNCaP and its hormone-refractory derivative C4-2B, using an antibody library-based affinity proteomic approach. We selected a naïve phage antibody display library to identify human single-chain antibodies that bind specifically to C4-2B but not LNCaP. Using mass spectrometry, we identified one of the antibody-targeted antigens as the ICAM-1/CD54/human rhinovirus receptor. Recombinant IgG1 derived from this single-chain antibody binds to a neutralizing epitope of ICAM-1 and blocks C4-2B cell invasion through extracellular matrix in vitro. ICAM-1 is thus differentially expressed during the transition of the hormone-sensitive prostate cancer cell line LNCaP to its hormone-refractory derivative C4-2B, plays an important role in imparting the C4-2B line with the ability to invade, and may therefore be a target for therapeutic intervention
High Frequency of CD4+CXCR5+ TFH Cells in Patients with Immune-Active Chronic Hepatitis B
BACKGROUND: T follicular helper (TFH) cells are a special subpopulation of T helper cells and can regulate humoral immune responses. This study examined whether the frequency of CD4(+)CXCR5(+) TFH cells could be associated with active immunity in chronic hepatitis B (CHB) patients. METHODOLOGY AND FINDINGS: The frequencies of peripheral blood CD4(+)CXCR5(+) TFH cells, inducible T cell costimulator (ICOS), and/or programmed death 1 (PD-1) positive CD4(+)CXCR5(+) TFH cells in immune-active (IA), immune-tolerant (IT) CHB, and healthy controls (HC) were characterized by flow cytometry analysis. The effect of adevofir dipivoxil treatment on the frequency of CD4(+)CXCR5(+) TFH cells, the concentrations of serum IL-2, IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-21, ALT, AST, HBsAg, HBsAb, HBeAg, HBeAb and HBV loads in IA patients were determined. The potential association of the frequency of CD4(+)CXCR5(+) TFH cells with clinical measures was analyzed. In addition, the frequency of splenic and liver CD4(+)CXCR5(+) TFH cells in HBV-transgenic mice was examined. We found that the frequency of CD4(+)CXCR5(+) TFH cells in IA patients was significantly higher than that of IT patients and HC, and the percentages of CD4(+)CXCR5(+) TFH in IA patients were positively correlated with AST. Furthermore, the percentages of ICOS(+), PD-1(+), and ICOS(+)PD-1(+) in CD4(+)CXCR5(+) TFH cells in CHB patients were significantly higher than that of HC. Treatment with adefovir dipivoxil reduced the frequency of CD4(+)CXCR5(+) TFH, PD-1(+)CD4(+)CXCR5(+) TFH cells and the concentrations of HBsAg and HBeAg, but increased the concentrations of HBsAb, HBeAb, IL-2 and IFN-γ in IA patients. Moreover, the frequency of splenic and liver CD4(+)CXCR5(+) TFH cells in HBV-transgenic mice was higher than that of wild-type controls. CONCLUSIONS: These data indicate that CD4(+)CXCR5(+) TFH cells may participate in the HBV-related immune responses and that high frequency of CD4(+)CXCR5(+) TFH cells may be a biomarker for the evaluation of active immune stage of CHB patients
Hepatitis B Virus X Protein Drives Multiple Cross-Talk Cascade Loops Involving NF-κB, 5-LOX, OPN and Capn4 to Promote Cell Migration
Hepatitis B virus X protein (HBx) plays an important role in the development of hepatocellular carcinoma (HCC). However, the mechanism remains unclear. Recently, we have reported that HBx promotes hepatoma cell migration through the upregulation of calpain small subunit 1 (Capn4). In addition, several reports have revealed that osteopontin (OPN) plays important roles in tumor cell migration. In this study, we investigated the signaling pathways involving the promotion of cell migration mediated by HBx. We report that HBx stimulates several factors in a network manner to promote hepatoma cell migration. We showed that HBx was able to upregulate the expression of osteopontin (OPN) through 5-lipoxygenase (5-LOX) in HepG2-X/H7402-X (stable HBx-transfected cells) cells. Furthermore, we identified that HBx could increase the expression of 5-LOX through nuclear factor-κB (NF-κB). We also found that OPN could upregulate Capn4 through NF-κB. Interestingly, we showed that Capn4 was able to upregulate OPN through NF-κB in a positive feedback manner, suggesting that the OPN and Capn4 proteins involving cell migration affect each other in a network through NF-κB. Importantly, NF-κB plays a crucial role in the regulation of 5-LOX, OPN and Capn4. Thus, we conclude that HBx drives multiple cross-talk cascade loops involving NF-κB, 5-LOX, OPN and Capn4 to promote cell migration. This finding provides new insight into the mechanism involving the promotion of cell migration by HBx
Diverse Applications of Nanomedicine
The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic. \ua9 2017 American Chemical Society
Atomic structures of Coxsackievirus A6 and its complex with a neutralizing antibody
手足口病是一种由人肠道病毒引起的全球性传染病,主要发生于5岁以下的婴幼儿,严重危害公众健康。根据获得的手足口病流行病学和病原学调查数据,目前认为CVA6与EV71和CVA16一样应作为优先的手足口病疫苗预防对象,亟需研制有效的预防和治疗方法。然而令人遗憾的是,目前对于CVA6的基础病毒学特别是结构生物学知识均缺乏足够了解,严重制约了相关研究的有效开展。
夏宁邵教授团队研究首次揭示了手足口病重要病原体柯萨奇病毒A组6型(CVA6)的病毒颗粒及其与中和抗体复合物的精确三维结构,为新型疫苗和治疗药物的研制提供了重要的理论基础。这项研究发现并精确描绘了CVA6的病毒颗粒及其与优势中和抗体的结构特征,首次完成了对CVA6的高精度“成像”,为新型疫苗和治疗药物研制提供了关键基础。
该研究工作在厦门大学分子疫苗学和分子诊断学国家重点实验室、国家传染病诊断试剂与疫苗工程技术研究中心科研平台完成。夏宁邵教授、颜晓东博士、程通副教授为该研究论文的共同通讯作者。颜晓东博士来自美国加州大学圣地亚哥分校,同时受聘为我校双聘教授。共同第一作者为徐龙发博士生、郑清炳工程师和李少伟教授。【Abstract】Coxsackievirus A6 (CVA6) has recently emerged as a major cause of hand, foot and mouth disease in children worldwide but no vaccine is available against CVA6 infections. Here, we demonstrate the isolation of two forms of stable CVA6 particles-procapsid and A-particle-with excellent biochemical stability and natural antigenicity to serve as vaccine candidates. Despite the presence (in A-particle) or absence (in procapsid) of capsid-RNA interactions, the two CVA6 particles have essentially identical atomic capsid structures resembling the uncoating intermediates of other enteroviruses. Our near-atomic resolution structure of CVA6 A-particle complexed with a neutralizing antibody maps an immune-dominant neutralizing epitope to the surface loops of VP1. The structure-guided cell-based inhibition studies further demonstrate that these loops could serve as excellent targets for designing anti-CVA6 vaccines.This work was supported by a grant from the National Natural Science Foundation of China (No. 31670933 and 81401669), the National Science and Technology Major Projects for Major New Drugs Innovation and Development (No. 2017ZX09101005-005-003), the National Science and Technology Major Project of Infectious Diseases (No. 2017ZX10304402-002-003) and the Natural Science Foundation of Fujian Province (No. 2015J05073). This work was also supported in part by funding to T.S.B. from the National Institutes of Health (Grant R37-GM33050).
研究工作也得到了国际病毒结构生物学权威专家美国加州大学洛杉矶分校周正洪教授的大力支持和帮助,获得了国家自然科学基金、新药创制国家科技重大专项、传染病防治国家科技重大专项和福建省自然科学基金的资助
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