51 research outputs found

    从经济特区的双重作用看它的未来地位

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    中国的经济特区既是改革开放和现代化建设的试验区、先行区、示范区,又是处于战略区位上的重要口岸城市,带动和组织区域经济发展的经济中心。这就是我们所说的经济特区的“两重性”。由此入手去研究经济特区,我们将会更深刻地认识它的发展机制和发展优势,更全面地了解它在历史进程中所能做出的业绩和贡献,从而更准确地预见特区未来的作用和地位。城市特区和特区城市特区与城市相结合、相促进,是中国经济特区的典型形态。在改革开放中,特区政策对城市发展的推动作用是显而易见的。如果不是创建经济特区,今天我们在深圳、珠海、汕头和厦门这些地方所见到的,大多还是

    Chemical Composition of Chinese Pyrola Herb Volatile and the Effects on the Osteoblast Proliferation

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    目的分析鹿衔草挥发油的化学成分,研究其对体外培养成骨细胞增殖的影响。方法采用水蒸气蒸馏法提取鹿衔草挥发油,GC-MS检测化学成分;鹿衔草挥发油干预成骨细胞系ROS17/2.8后,采用MTT法检测成骨细胞增殖,流式细胞术检测成骨细胞增殖周期,实时荧光定量PCR检测成骨细胞PCNA mRNA表达。结果一定浓度的鹿衔草挥发油能促进成体外培养成骨细胞增殖,处于增殖周期的成骨细胞比例明显增加,且成骨细胞的增殖细胞核抗原(Proliferating Cell Nuclear Antigen,PCNA)mRNA表达显著提高。结论鹿衔草挥发油通过上调PCNA表达,加速成骨细胞增殖周期进程,从而促进成骨细胞增殖。Objective To analyze the chemical composition of Chinese pyrola herb volatile and study its effects on the in vitro cultured osteoblast proliferation. Methods The water vapor distillation was used to extract Chinese pyrola herb volatile and GC- MS was to determine the chemical composition. After intervention of Chinese pyrola herb volatile on ROS17 /2. 8,MTT method was adopted to determine the osteoblast proliferation,the flow cytometry was to determine the osteoblast proliferating cycle and RT- PCR was to determine the expression of PCNA mRNA. Results Chinese pyrola herb volatile of a certain of concentration promoted the proliferation of in vitro cultured osteoblast cells. The percentage of osteoblast cells in the proliferation cycle was increased apparently and the expression of PCNA mRNA was improved significantly. Conclusion Chinese pyrola herb volatile accelerates the progression of osteoblast proliferating cycle through up- regulating PCNA expression so as to accelerate osteoblast proliferation.国家自然科学基金(81473706);; 福州市卫生系统科技计划项目(2013-S-wq10);; 福建省中医药科研项目(wzgs201307

    Effects of Jiangu Granules on the proliferation of osteoblasts through G_1/S phase cell-cycle regulated proteins

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    目的观察健骨颗粒对成骨细胞G_1/S期调控的影响,探讨健骨颗粒促进成骨细胞增殖的作用机制。方法制备健骨颗粒血清组、模型血清组和雌二醇血清组。采用酶消化法培养SD大鼠成骨细胞,健骨颗粒含药血清干预,以模型血清和雌二醇血清为对照。运用流式细胞术检测成骨细胞增殖周期,荧光定量PCR法检测成骨细胞G_1/S期调控蛋白Cyclin E、CDK2、p21和转录因子E2F-1 m RNA的表达。结果 15%的雌二醇血清与健骨颗粒血清干预48 h,成骨细胞增殖速度均明显快于模型血清组(P<0.01);G_0/G_1期成骨细胞比例明显降低(P<0.01),S期、G_2/M期细胞比例及增殖指数则明显高于模型血清组(P<0.01);与模型血清组比较,雌二醇血清组与健骨颗粒血清组能提高成骨细胞Cyclin E、CDK2及转录因子E2F-1 m RNA的表达(P<0.01),而降低p21的表达(P<0.01)。结论健骨颗粒通过调节成骨细胞G_1/S期调控机制,推进成骨细胞顺利通过G_1/S检测点,促进成骨细胞增殖。Objective To observe the effects of Jiangu Granules on the G_1/S phase cell-cycle regulated proteins of osteoblasts, so as to reveal the mechanism of Jiangu Granules in promoting osteoblasts proliferation. Methods The Jiangu Granules-serum group, model-serum group and estradiol-serum group were prepared. Osteoblasts of SD rats were cultivated by enzymatic digestion and intervened with Jiangu Granules-serum, model-serum and estradiol-serum(as control) respectively. The cell cycles were analyzed by flow cytometry, while the fluorescence quantitative PCR was applied to measure cyclin E, CDK2, p21 and E2F-1 m RNA. Results The cell proliferation rates of osteoblasts intervened with estradiol serum and Jiangu Granules-serum for 48 hours were faster than that with the same concentration model-serum(P < 0.01). Compared with the model-serum group, the proportion of osteoblasts in the G_0/G_1 phase were significantly reduced after intervention with 15% of estradiol serum and Jiangu Granules-serum for 48 hours(P < 0.01),while the proportion of cells in S phase, G_2/M phase and proliferation index was much higher(P < 0.01). The expression of cycling E, CDK 2 and transcription factor E2F-1 m RNA of osteoblasts in the Jiangu Granules-serum group and the estradiol-serum group was higher than that of model-serum group(P < 0.01), while the expression of p21 m RNA was lower than the model-serum group(P < 0.01). Conclusion Jiangu Granules-serum can adjust the G_1/S phase cellcycle regulated mechanism in osteoblast, so as to push the cells passing G_1/S checkpoint and accelerate the proliferation of osteoblast.国家自然科学基金资助项目(81473706

    对价支付影响因素的理论和实证分析

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    我国上市公司股权分置改革成功与否关系我国证券市场未来的发展。本文根据财务理论,结合国情构建6个研究假设,并以330家实施股权分置改革的上市公司为样本,应用实证研究方法,探讨非流通股东的对价送出率及流通股东的对价送达率的影响因素。研究发现股改工作中所采用的市场化博弈机制可在一定程度上保障对价方案的合理性和两类股东的利益,但仍存在诸如机构投资者未发挥议价能力等问题

    七种捕食性鱼类对中华绒螯蟹幼蟹捕食风险的评估

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    分别以鲤、鳜、斑点叉尾、黄颡鱼、瓦氏黄颡鱼、大口鲇和乌鳢作为捕食者,以中华绒螯蟹幼蟹作为猎物,在室内水泥池(2.4 m3)进行捕食试验。以日捕获率和日摄食率为指标,评估这些鱼类对幼蟹的捕食作用和危害程度,为提高湖泊幼蟹放流效果、建立蟹—鱼复合的优质高效养殖模式提供科学依据。在幼蟹完全暴露的条件下,经过多次(至少9次)重复的试验(短期1d和长期7d),鳜对不同大小的硬壳和软壳(刚蜕壳的)幼蟹没有任何捕食作用;黄颡鱼对硬壳和软壳幼蟹也没有捕食作用,但还需做进一步观察;虽然鲤、瓦氏黄颡鱼对硬壳蟹的捕获率低,但对软壳的幼蟹有较大的危害性,对幼蟹的日摄食率分别为0.070%、0.012%;大口鲇、斑点叉尾、乌鳢对幼蟹具有较强的捕食能力,对幼蟹的日摄食率分别为0.122%、0.188%和0.284%。根据这些研究结果,可以建议:(1)在池塘和湖泊河蟹养殖中,完全可以将鳜作为套养或混养对象,以期提高养殖效益;(2)在河蟹放养的湖泊,需要抑制乌鳢和大口鲇种群,适当减少鲤和瓦氏黄颡鱼丰度,以期减少这些鱼类的捕食作用,提高幼蟹存活率;(3)在河蟹养殖池塘,不能放养乌鳢、大口鲇、斑点叉尾、瓦氏黄颡鱼和鲤

    2017年春季鲍鱼苗种生产情况调研分析

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    为准确把握2017年鲍鱼生产形势,我们组织开展2017年春季鲍鱼苗种生产情况调研。本次调研采取问卷调查、电话咨询、现场走访及专家会商等方式进行。总体上看,2017年春季鲍鱼苗种生产增量幅度较大,已超过养殖需求,苗价回落明显;今年投苗量增加明显,正常情况下,明年养殖存塘量随之增大,预计明年商品鲍鱼可能面临新一轮的跌价考验

    Probing the edge-related properties of atomically thin MoS2 at nanoscale

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    层状二维材料具有独特的物理化学性质,使其在光电器件、传感、能源和催化等领域得到了高度关注和广泛应用。二维材料在制备过程中不可避免引入结构缺陷,虽然这些缺陷尺度仅为数纳米甚至单原子,但是会极大地改变材料的结构和电子性质,从而影响其应用。化学化工学院任斌教授课题组在层状二维材料缺陷表征方面取得进展。该工作表明了TERS在原位、高空间分辨表征缺陷位的结构和电子性质方面具有独特的优势,可以进一步推广到其他二维材料,从而有效地指导缺陷设计和材料应用。 该工作通过校内外课题组紧密合作,在任斌教授、谭平恒研究员(中科院半导体研究所)和王翔博士共同指导下完成。实验部分主要由黄腾翔博士(第一作者,已毕业化学系博士生)完成,电子能带结构与光谱理论计算由谭平恒研究员课题组从鑫博士生(共同第一作者)完成,吴思思、林楷强、姚旭、何玉韩、吴江滨、包一凡、黄声超等参与了实验与讨论。【Abstract】Defects can induce drastic changes of the electronic properties of two-dimensional transition metal dichalcogenides and influence their applications. It is still a great challenge to characterize small defects and correlate their structures with properties. Here, we show that tipenhanced Raman spectroscopy (TERS) can obtain distinctly different Raman features of edge defects in atomically thin MoS2, which allows us to probe their unique electronic properties and identify defect types (e.g., armchair and zigzag edges) in ambient. We observed an edgeinduced Raman peak (396 cm−1) activated by the double resonance Raman scattering (DRRS) process and revealed electron–phonon interaction in edges. We further visualize the edge-induced band bending region by using this DRRS peak and electronic transition region using the electron density-sensitive Raman peak at 406 cm−1. The power of TERS demonstrated in MoS2 can also be extended to other 2D materials, which may guide the defect engineering for desired properties.The authors acknowledge the final supports from MOST of China (2016YFA0200601 and 2016YFA0301204), NSFC (21633005, 21790354, 21503181, 21711530704, 21621091, 11874350, 11474277, and 11434010), Natural Science Foundation of Fujian Province (2016J05046), and China Postdoctoral Science Foundation (2017M622062). 研究工作得到科技部、国家自然科学基金委员会、福建省自然科学基金和中国博士后基金资助

    In situ Raman spectroscopic evidence for oxygen reduction reaction intermediates at platinum single crystal surfaces

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    铂基催化剂表面的氧还原反应(ORR)是燃料电池重最重要的阴极反应。虽然经过几十年的研究,ORR的具体反应路径并没有真正解析清楚。在本研究中,李剑锋教授课题组首次利用其发展的电化学壳层隔绝纳米粒子增强拉曼光谱(SHINERS)技术原位研究了Pt(hkl)单晶表面的ORR反应过程,成功捕获到在1150 cm-1、1080 cm-1和732 cm-1区域O2-、OH*和HO2*等重要反应中间物种的直接拉曼光谱证据,并通过相应的同位素取代实验(氘和O-18同位素实验)及DFT理论模拟确认了中间物种的谱峰归属和吸附构型。总的来说,该项研究首次在Pt(hkl)单晶表面原位获得ORR反应重要中间物种的直接拉曼光谱证据,提出合理的ORR反应路径,加深了人们对ORR反应机理的认识,也为其他界面催化反应机理的研究提供了一条可行的研究思路。 该研究工作由校内外多个课题组共同努力完成,化学化工学院李剑锋教授课题组负责相关电化学原位拉曼光谱实验,Alicante大学Juan Feliu教授课题组负责单晶电化学实验,化学化工学院吴德印教授课题组负责DFT理论模拟,物理系杨志林教授课题组负责3D-FDTD的理论模拟。该研究工作的第一作者董金超和第二作者张霞光分别为化学化工学院2014级博士生(已毕业)和2015级博士生。【Abstract】Developing an understanding of structure-activity relationships and reaction mechanisms of catalytic processes is critical to the successful design of highly efficient catalysts. As a fundamental reaction in fuel cells, elucidation of the oxygen reduction reaction (ORR) mechanism at Pt(hkl) surfaces has remained a significant challenge for researchers. Here, we employ in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculation techniques to examine the ORR process at Pt(hkl) surfaces. Direct spectroscopic evidences for ORR intermediates indicates that under acid conditions, the pathway of ORR at Pt(111) occurs through the formation of HO2, while at Pt(110) and Pt(100) it occurs via the generation of OH*. However, we propose that the pathway of ORR under alkaline conditions at Pt(hkl) surfaces mainly occurs through the formation of O2- . Significantly, these results demonstrate that the SERS technique offers an effective and reliable way for real-time investigation of catalytic processes at atomically flat surfaces.This work was supported by the NSFC (21522508, 21427813, 21521004, 21533006, 21621091,and 21775127), "111" Project (B16029 and B17027), Natural Science Foundation of Guangdong Province (2016A030308012), the Fundamental Research Funds for the Central Universities (20720180037), and the Thousand Youth Talents Plan of China. Support from MINECO and Generalitat Valenciana (Spain), through projects CTQ2016-76221-P (AEI/FEDER, UE) and PROMETEOII/2014/013 respectively, is greatly acknowledged. V.B.M thankfully acknowledges to MINECO the award of a pre-doctoral grant (BES-2014-068176, project CTQ2013-44803-P). 该研究工作得到国家自然科学基金委(21522508、21427813、21521004、21533006、21621091和21775127)的大力资助和支持。化学化工学院周志有教授、程俊教授,材料学院张华副教授,英国利物浦大学Gary Attard教授,以及化学化工学院苏敏、王耀辉、卢邦安等博士生和杨晓冬博士对本课题的研究给予了大力的支持和帮助
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