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Search Results: 1 - 10 of 50939 matches for " ZhenQing Wei "
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Analysis on Supporting Policy of Small and Medium Enterprises of Science and Technology—Taking Hefei of Anhui Province as an Example  [PDF]
Zhenqing Yuan, Yujie Feng
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.54013
Abstract: In recent years, as the carrier of technology innovation and technology industrialization, science-technology small and medium-sized enterprises (STS-ME) make big contribution to transformation of scientific and technological achievements, the industrial structure optimization, the high and new technology development, innovation/entrepreneurship and increasing employment opportunities. STSME has become an important growth point of economic development. However, support policies for STSME also face many problems as policies and regulations and public service system is not perfect, poor financial ecological environment, the relative lack of scientific and technological personnel, to some extent, which hinders the development of STS-ME. Therefore, this article using policy text analysis method-through the extraction and analysis method of keyword network keywords to analyze policies which supports STSME in Hefei. According to the analysis results, we put forward policy recommendations.
Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells
Kai Wei,Xiaojun Xu,Ximing Pu,Zhenqing Hou
Nanoscale Research Letters , 2011,
Abstract: The evaluation of the toxicity of magnetic nanoparticles (MNPs) has attracted much attention in recent years. The current study aimed to investigate the cytotoxic effects of Fe3O4, oleic acid-coated Fe3O4 (OA-Fe3O4), and carbon-coated Fe (C-Fe) nanoparticles on human hepatoma BEL-7402 cells and the mechanisms. WST-1 assay demonstrated that the cytotoxicity of three types of MNPs was in a dose-dependent manner. G1 (Fe3O4 and OA-Fe3O4) phase and G2 (C-Fe) phase cell arrests and apoptosis induced by MNPs were detected by flow cytometry analysis. The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol. Moreover, apoptosis was further confirmed by morphological and biochemical hallmarks, such as swollen mitochondria with lysing cristae and caspase-3 activation. Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway. The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4.
New Method to Prepare Mitomycin C Loaded PLA-Nanoparticles with High Drug Entrapment Efficiency
Hou Zhenqing,Wei Heng,Wang Qian,Sun Qian
Nanoscale Research Letters , 2009,
Abstract: The classical utilized double emulsion solvent diffusion technique for encapsulating water soluble Mitomycin C (MMC) in PLA nanoparticles suffers from low encapsulation efficiency because of the drug rapid partitioning to the external aqueous phase. In this paper, MMC loaded PLA nanoparticles were prepared by a new single emulsion solvent evaporation method, in which soybean phosphatidylcholine (SPC) was employed to improve the liposolubility of MMC by formation of MMC–SPC complex. Four main influential factors based on the results of a single-factor test, namely, PLA molecular weight, ratio of PLA to SPC (wt/wt) and MMC to SPC (wt/wt), volume ratio of oil phase to water phase, were evaluated using an orthogonal design with respect to drug entrapment efficiency. The drug release study was performed in pH 7.2 PBS at 37 °C with drug analysis using UV/vis spectrometer at 365 nm. MMC–PLA particles prepared by classical method were used as comparison. The formulated MMC–SPC–PLA nanoparticles under optimized condition are found to be relatively uniform in size (594 nm) with up to 94.8% of drug entrapment efficiency compared to 6.44 μm of PLA–MMC microparticles with 34.5% of drug entrapment efficiency. The release of MMC shows biphasic with an initial burst effect, followed by a cumulated drug release over 30 days is 50.17% for PLA–MMC–SPC nanoparticles, and 74.1% for PLA–MMC particles. The IR analysis of MMC–SPC complex shows that their high liposolubility may be attributed to some weak physical interaction between MMC and SPC during the formation of the complex. It is concluded that the new method is advantageous in terms of smaller size, lower size distribution, higher encapsulation yield, and longer sustained drug release in comparison to classical method.
Hydrogels for Cardiac Tissue Engineering
Zhenqing Li,Jianjun Guan
Polymers , 2011, DOI: 10.3390/polym3020740
Abstract: Cardiac tissue regeneration is an integrated process involving both cells and supporting matrix. Cardiomyocytes and stem cells are utilized to regenerate cardiac tissue. Hydrogels, because of their tissue-like properties, have been used as supporting matrices to deliver cells into infarcted cardiac muscle. Bioactive and biocompatible hydrogels mimicking biochemical and biomechanical microenvironments in native tissue are needed for successful cardiac tissue regeneration. These hydrogels not only retain cells in the infarcted area, but also provide support for restoring myocardial wall stress and cell survival and functioning. Many hydrogels, including natural polymer hydrogels, synthetic polymer hydrogels, and natural/synthetic hybrid hydrogels are employed for cardiac tissue engineering. In this review, types of hydrogels used for cardiac tissue engineering are briefly introduced. Their advantages and disadvantages are discussed. Furthermore, strategies for cardiac regeneration using hydrogels are reviewed.
Human Discharge and Phytoplankton Takeup for The Atmospheric Carbon Balance  [PDF]
Dongfang Yang, Zhenqing Miao, Yu Chen, Qiang Shi, Huanzhi Xu
Atmospheric and Climate Sciences (ACS) , 2011, DOI: 10.4236/acs.2011.14021
Abstract: By the data of the Jiaozhou Bay (Shandong, China) from May 1991 to February 1994 and those of Hawaii from March 1958 to December 2007, with the statistics and differential equations analyzed were the seasonal variations in atmospheric carbon in the Northern Pacific Ocean (NPO), and in phytoplankton primary production in the Jiaozhou Bay, and its relationship in the study regions. The study unveiled that the seasonal change of the atmosphere carbon and primary production has the same period. In a year, the primary production and atmosphere carbon had two balance points: the points of May and October, during which the amount of atmosphere carbon decreased. As phytoplankton absorbed atmosphere carbon, When primary production in spring > 181.60 (mg/m2 d) ~ 297.57 (mg/m2 d) or 754.74 (mg/m2 d) ~ 1160.13 (mg/m2 d) in Sept. or 552.94 (mg/m2 d) ~ 890.69 (mg/m2 d) in Oct, the atmosphere carbon fell. Therefore, it is considered that from May to Oct. every year, phytoplankton growing in bloom controlled the increase of atmosphere carbon. From Dec. to next April, human discharging the carbon controlled its increase. The results supported the viewpoint shown by Yang (2010): the variation in atmospheric carbon was determined by human discharge and phytoplankton growth. The result in this paper showed that the earth ecosystem kept the percentage of the decrease amount of atmospheric carbon to its amount taken up by phytoplankton as 1.60% ~ 0.34% and maintained the dynamic balance of carbon by emitted by human being into the atmosphere and absorption of phytoplankton to atmosphere carbon. Therefore, the ecosystem was considered to be of the great power and accuracy.
Input Quantity and Distribution of Hexachlorocyclohexane (HCH) in the Jiaozhou Bay Waters  [PDF]
Dongfang Yang, Ziru Ding, Zhenqing Miao, Huanzhi Xu, Hongyan Bai
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.43017
Abstract: Based on data from the investigation in Jiaozhou bay waters in May, July and November in 1987, the distribution, source and seasonal variation of HCH in Jiaozhou Bay are analyzed. The results showed that in Jiaozhou bay HCH content was very low and less than 0.100 μg/L in this year, and better than the national Category I of the sea water quality standard, and the water quality about HCH was very clean; and that The seasonal variation of the HCH content in Jiaozhou bay waters has already vanished, namely, the seasonal variation of the HCH content in this year was not influenced by the rainfall, the runoffs or rivers. The horizontal distributions of the HCH content in the whole bay waters showed that the HCH content in the bay was not only directly input from both runoffs but also from rivers, the HCH source was area-source and came from land. The vertical distributions of the HCH content in the whole bay waters showed that the change of the HCH content at surface was not consistent with the corresponding one at bottom, and that the trend of the HCH distribution at surface was not consistent with that at bottom, and that only the HCH contents at surface and bottom were very close. From the year of four years ago of the prohibition (1979), to the prohibition year of HCH use (1983), and finally to the year after the four years of the prohibition (1987), The change of the HCH input into the bay waters unveiled that the by four years before the prohibition, the pollution of the HCH on land was very grave, and by four years after the prohibition, the HCH content in waters was very low, whose process represented that the process of human being having broken up the earth and the process of the earth having naturally restored. Therefore, Human being would consider not only for own benefits but also for the sustainable development of environment.
Folate receptor-mediated boron-10 containing carbon nanoparticles as potential delivery vehicles for boron neutron capture therapy of nonfunctional pituitary adenomas
CongXin Dai,Feng Cai,Kuo Chu Hwang,YongMao Zhou,ZiZhu Zhang,XiaoHai Liu,SiHai Ma,YaKun Yang,Yong Yao,Ming Feng,XinJie Bao,GuiLin Li,JunJi Wei,YongHui Jiao,ZhenQing Wei,WenBin Ma,RenZhi Wang
Science China Life Sciences , 2013, DOI: 10.1007/s11427-012-4433-5
Abstract: Invasive nonfunctional pituitary adenomas (NFPAs) are difficult to completely resect and often develop tumor recurrence after initial surgery. Currently, no medications are clinically effective in the control of NFPA. Although radiation therapy and radiosurgery are useful to prevent tumor regrowth, they are frequently withheld because of severe complications. Boron neutron capture therapy (BNCT) is a binary radiotherapy that selectively and maximally damages tumor cells without harming the surrounding normal tissue. Folate receptor (FR)-targeted boron-10 containing carbon nanoparticles is a novel boron delivery agent that can be selectively taken up by FR-expressing cells via FR-mediated endocytosis. In this study, FR-targeted boron-10 containing carbon nanoparticles were selectively taken up by NFPAs cells expressing FR but not other types of non-FR expressing pituitary adenomas. After incubation with boron-10 containing carbon nanoparticles and following irradiation with thermal neutrons, the cell viability of NFPAs was significantly decreased, while apoptotic cells were simultaneously increased. However, cells administered the same dose of FR-targeted boron-10 containing carbon nanoparticles without neutron irradiation or received the same neutron irradiation alone did not show significant decrease in cell viability or increase in apoptotic cells. The expression of Bcl-2 was down-regulated and the expression of Bax was up-regulated in NFPAs after treatment with FR-mediated BNCT. In conclusion, FR-targeted boron-10 containing carbon nanoparticles may be an ideal delivery system of boron to NFPAs cells for BNCT. Furthermore, our study also provides a novel insight into therapeutic strategies for invasive NFPA refractory to conventional therapy, while exploring these new applications of BNCT for tumors, especially benign tumors.
Exploring Tourist Adoption of Tourism Mobile Payment: An Empirical Analysis
Peng,Runhua; Xiong,Li; Yang,Zhenqing;
Journal of theoretical and applied electronic commerce research , 2012, DOI: 10.4067/S0718-18762012000100003
Abstract: with recent developments in mobile technologies, tourism mobile payment(m-payment) is beginning to offer interesting and beneficial new services. this research aimed to identify the factors determining tourists' acceptance of tourism m-payment. based on literature relating to the tam theory, the conceptual model is developed and tested in this research. this research extends the applicability of the tam in tourism m-payment context, by adding the system characteristics' constructs and tourism characteristics' constructs to the model. data collected from 421 tourists in china were tested against the extended tam, using the structural equation modeling approach. the empirical results show especially strong support for the effects of perceived security, perceived compatibility, destination m-payment knowledge, and tourist susceptibility to interpersonal influence. the findings provide a foundation for an enhanced theory on tourism m-payment adoption and for the practical development of tourism m-payment service.
Double-gating mechanism and diversity of an adenosine triphosphate (ATP)-sensitive K+ channel in neurons acutely dissociated from rat neocortex
Zhenqing Tong,Xiangdong Tang,Wenjun Yang
Science China Life Sciences , 1997, DOI: 10.1007/BF02879102
Abstract: Classically, ion channels are classified into 2 groups: chemical-sensitive (ligand-gated) and voltage sensitive channels. Single ATP-sensitive K+ (K-ATP) channel currents were recorded in acutely dissociated rat neocortical neurons using patch clamp technique. A type of K-ATP channel has been found to be gated not only by intracellular ATP, but also by membrane potential (Vm), and proved to be a novel mechanism underlying the gating of ion channels, namely bi-gating mechanism. The results also show that the K-ATP channels possess heterogeneity and diversity. These types of K-ATP channels have been identified in 40.12% of all patches, which are different in activation-threshold and voltage-sensitivity. The present experiment studied the type-3 K-ATP channel with a unitary conductance of about 80 pS in detail (n = 15). Taking account of all the available data, a variety of K-ATP channels are suggested to exist in body, and one type of them is bi-gated by both chemical substances and membrane potentials. This property of the K-ATP channels may be related to their pathophysiological function.
DYNAMIC CRACK-TIP FIELD IN AN ELASTIC-VISCOPLASTIC MATERIAL
粘弹塑性材料动态裂纹尖端场

Wang Zhenqing,
王振清

力学学报 , 1993,
Abstract: The asymptotic analysis of he stress and strain field at a propagating crack tip is given by means of an elastic-viscoplastic model. It is assumed that the viscosity effect can be neglected for elasticity strain, and only for plasticity strain, the viscosity is significant. By use of this model, the constitutive relations of a rate sensitive material and the dynamic equations of the stress and strain field a crack-tip are derived. The stress and strain singularity exponent of crack-tip field is given by means of the asymptotic analysis. The matching condition among elastisity, plastisity and viscosity is discussed. For anti-plane shear crack the detailed analysis is given. The numerical calcula tions are carried out for various parameters of materials. The feature of the numerical solutions is discussed in detail.
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