纳米材料的研究进展

总结了近几年来纳米材料的研究进展，着重从纳米材料的制备、微观结构、力学及热力学性能的研究情况作了一个概述，总结了有关纳米材料的几个研究热点以及分子动力学计算机模拟在纳米材料研究中的应用。最后并指出出几个急待研究的工作

知识资本保值增值财务衡量指标体系设计

从知识资本保值增值财务衡量目的出发,在分析知识资本保值增值财务衡量理论的基础上,构建了知识资本保值增值财务衡量指标体系,并介绍了其指标差异的分析方法,以评价知识资本保值增值水平和能力,为知识资本运营与管理决策提供依据

试析我国民办高校的投入机制

●开辟民办高校的多渠道经费来源,不单纯依赖学费。●提供各投入主体的多种利益,激励他们投入民办高校的积极性。●尽快制订《民办教育促进法》实施细则,解决合理回报、营利等问题。●健全各种社会机制,发挥评价的作用

大学生“村官”社交心态探析

在对福建泉州大学生“村官“基层社会关系调研的基础上,文章首先分析了大学生“村官“基层社会关系呈现的社交格局差序化、社交联结功能化、社交互动结构化和社交测量复杂化等特质,随后指出其在基层社会交往中存在的问题,并从大学生“村官“软实力打造和政府层面的制度保障两个角度进行思考

Transcriptional regulation of PEN-2, a key component of the γ-secretase complex, by CREB

Gamma-secretase, which is responsible for the intramembranous cleavage of Alzheimer's P-amyloid precursor protein (APP), the signaling receptor Notch, and many other substrates, is a multiprotein complex consisting of at least four components: presenilin (PS), nicastrin, APH-1, and PEN-2. Despite the fact that PEN-2 is known to mediate endoproteolytic cleavage of full-length PS and APH-1 and nicastrin are required for maintaining the stability of the complex, the detailed physiological function of each component remain elusive. Unlike that of PS, the transcriptional regulation of PEN-2, APH-1, and nicastrin has not been investigated. Here, we characterized the upstream regions of the human PEN-2 gene and identified a 238-bp fragment located 353 bp upstream of the translational start codon as the key region necessary for the promoter activity. Further analysis revealed a CREB binding site located in the 238-bp region that is essential for the transcriptional activity of the PEN-2 promoter. Mutation of the CREB site abolished the transcriptional activity of the PEN-2 promoter. Electrophoretic mobility shift assays and chromatin immunoprecipitation analysis showed the binding of CREB to the PEN-2 promoter region both in vitro and in vivo. Activation of the CREB transcriptional factor by forskolin dramatically promoted the expression of PEN-2 mRNA and protein, whereas the other components of the gamma-secretase complex remained unaffected. Forskolin treatment slightly increases the secretion of soluble APP alpha and A beta without affecting Notch cleavage. These results demonstrate that expression of PEN-2 is regulated by CREB and suggest that the specific control of PEN-2 expression may imply additional physiological functions uniquely assigned to PEN-2

ECAP制备纯Cu的热处理工艺与力学性能

Cu经过等径角挤压(ECAP)变形后,屈服强度达到了约400 MPa,然而加工硬化能力不足导致其在小应变阶段就开始颈缩(≤2%) 。研究发现,可以通过部分再结晶退火调控变形Cu的室温准静态拉伸性能。在275 ℃退火10 min后,其准静态拉伸强度和塑性得到了良好的匹配:在保持屈服强度为330 MPa的前提下,均匀伸长率达5%

Preparation and in vitro evaluation of chitosan microspheres containing matrine

目的:以壳聚糖为囊材制备苦参碱结肠靶向给药微球及评价其体外释药情况。方法:用乳化化学交联法制备微球,以微球的粒径分布百分数、载药量及包封率为优化指标对影响微球制备的主要因素用正交试验设计优化制备条件;并对最佳制备工艺制得的微球进行3种不同递质(人工胃液、人工肠液及大鼠结肠液)中的体外释放度评价。结果:制得的苦参碱壳聚糖微球在电镜下,球形表面圆整,粒径分布适宜,微球平均粒径为(68.3±2.7)μm,平均载药量为(16.0±0.5)%,平均包封率为(66.3±4.2)%。苦参碱壳聚糖微球在人工胃液中2h不释药;在人工肠液中4h内释放不到1%,96h释药不到10%;在含大鼠结肠内容物的磷酸盐缓冲液(pH6.8)中4h释放10%左右,36h释药近50%,此后释药趋于缓慢,96h释药近80%。结论:苦参碱壳聚糖微球几乎不在上消化道释药,而是在结肠靶向释药。OBJECTIVE To preparate the chitosan microspheres containing matrine for the colon-specific drug delivery and evaluate its release in vitro.METHODS The chitosan microspheres containing matrine were prepared by emulsion-chemical crosslink technique.The better preparation procedure with respect to particles size distribution,embedding rate and drug loading were optimized by the orthogonal experimental design.In-vitro drug release were carried out in the artificial gastric,artificial intestinal and the phosphate buffered saline(pH(6.8)) containing rat colon contents.RESULTS The chitosan microspheres containing matrine was shown to have good spherical geometry,a smooth surface and suitable size distribution under scanning electron micrographs.Average diameter of microspheres was((68.3)±(2.7))μm,drug loading was((16.0)±(0.5))%,embedding rate ((66.3)±(4.2))%.Little release and a little release of matrine from the microspheres were observed in the artificial gastric juice and in the artificial intestinal juice,respectively.However,the release of matrine was markedly increased in the phosphate buffered saline(pH(6.8)) containing rat colon contents,which was near to 10%,50% and 80% at 4 h,36 h and 96 h,respectively.CONCLUSION These findings suggest that the chitosan microspheres containing matrine may be useful a dosage form for colon-specific drug delivery.甘肃省自然科学基金(编号ZS0001-A23-073-Y

Calcuim depletion in forest ecosystem induced by acid rain: a review

通讯作者Corresponding author. E2mail: zhenghl@xmu. edu. cn[中文文摘]酸雨作为一个全球性环境问题,随着我国经济的快速发展,其危害也日益严重。诸多长期观测研究认为酸雨导致森林生态系统营养流失,特别是Ca的流失是酸雨导致森林衰退的一个重要原因。长期酸雨影响下,土壤中的Ca大量流失,在红壤等酸性土壤中表现得尤为严重;此外酸雨也会直接淋溶出植物叶片中的Ca,造成林冠中Ca不同程度的淋溶流失,并可能造成叶片Ca含量下降。且酸雨会导致叶片细胞内Ca稳态的失衡,影响植物的正常生理响应。对于整个森林生态系统而言,酸雨改变了生态系统中Ca生物地球化学循环的特征,大量的Ca从森林生态系统中以地表径流的形式流出系统,导致可利用Ca库的下降和周转速率的上升。酸雨对森林土壤、植物及生态系统各层面中的Ca均造成了长期广泛的影响,深入研究其影响程度与植物的应对机制,对我国酸雨危害区的酸雨防治和森林保育具有重大意义。[英文文摘]Acid rain is a global environmental p roblem that has become a very serious issue in China coup led with the rapid economic growth. The loss of nutrients in forest ecosystems, especially calcium, as shown in a lot of references done over long-term observation and research, is one of the key factors which indicate that acid rain caused the decline of forest ecosystems. Calcium has been markedly leached from the soils by acid rain, mostly in acidic soils such as red soils. Acid rain has also leached calcium from the canopy of forest resulting in a decrease of the folia calcium content sometimes, imbalance of calcium homeostasis at the cellular level, impair of physiological responses. From the ecosystem aspect, acid rain changed the characteristics of calcium biogeochemical cycle, brought calcium to be dep leted from the ecosystem in the surface runoff, reduced the bioavailable calcium pool and increased the turnover rate. Because acid rain influenced calcium at different levels of the ecosystem, it is important that we focus on studying the calcium dep letion and responses of p lants under long2term acid rain, which can help us in the p rogressive p revention and treatment of acid rain and the conservation of forest ecosystems.国家自然科学基金资助项目(30930076,30670317,30770192);厦门大学新世纪优秀人才基金资助项目(NCETXMU07115);长江学者和创新团队发展计划资助项

Experimental Study on Enhancement of Ammonia Bubble Absorption Process by Adding Nanoparticles

From the Danckwerts theoretical surface renewal model of mass transfer,an approach using nanoparticles to enhance ammonia bubble absorption process was examined in this study.In our experiment,the ammonia vapor flow flux and the concentration ratio of bulk ammonia solution were adjusted and their effects on ammonia bubble absorption were explored.The experimental results show that the absorption ratio was significantly increased by adding Al2O3 nanoparticles in the bulk solution,and the effective absorption..

通过锌催化区域选择性氧化反应实现3-烯-1-炔的1,4-官能团化

γ-羟基或烷氧基取代的α,β-不饱和羰基化合物广泛存在于众多天然产物和生物活性分子之中.本工作通过锌催化的区域选择性的氮氧化合物氧化炔烃反应,实现了3-烯-1-炔的4-烷氧化-1-氧化官能团..