118 research outputs found
The Synthesis and Characterization of Osmacycle Complexes with Two Phosphonium Substituents
含过渡金属的杂环化合物因其特殊的分子结构、化学活性以及潜在的应用价值,在金属有机化学中占有重要的地位。因此,对金属杂环化合物的反应性进行探究是金属有机化学领域备受关注的热点研究。本论文通过设计修饰双季鏻金属锇杂戊搭烯,合成了去芳构化的金属锇杂稠环化合物,实现了芳香性的转变;我们对去芳构化的金属锇杂稠环化合物的反应性进行了系统的研究,一方面将经典的Wittig反应拓展到金属有机体系,不仅得到了Wittig反应的产物,而且得到了Wittig反应过程中的偶极中间体,另一方面首次发现了金属杂环体系的自发拆分现象,此外还实现了去芳构化金属锇杂稠环化合物与亲电试剂的反应;另外,我们通过大量实验摸索后,合成...Transition-metal-containing metallacycles plays an important role in organometallic chemistry because of their special molecular structure, chemical reactivity and potential applications. Therefore, research on reactivity of osmacycles is in hotspot. In this dissertation, we designed and synthesized dearomatic osmacycles, achieved a transformation of aromaticity. We explored the reactivity of dear...学位:理学硕士院系专业:化学化工学院_高分子化学与物理学号:2052013115165
Genome Annotation for Eukaryotes and Analysis of Prokaryote Genome Sequencing Data
生物按照细胞类型分类有真核生物与原核生物,本文主要从真核生物与原核生物两个角度研究生物信息领域的意义所在。 随着高通量测序技术的发展,大量物种被测序并装配获得基因组序列。然而,如何快速准确地注解真核基因组的结构仍然是一个重要问题。目前注解一个真核基因组需要大量来源可靠、不同类型的参考数据源,例如相同或近似物种的蛋白质序列、EST、cDNA序列以及RNA-Seq数据。收集大量可靠的数据,并整合不同数据的分析结果,获得一致、完整的注解结果是一项耗时复杂的工作。因此,本研究第一部分提出一种快速便捷的计算工具GASS,利用相似物种的注解信息来完成一个新物种基因组的结构注解。首先将相似物种的外显子序列...With the development of high-throughput sequencing techniques, more and more genomes are sequenced and assembled. However, annotating a genome’s structure rapidly and expressly remains challenging. Current eukaryotic genome annotations require various, abundant supporting data, such as: species-specific and cross-species protein sequences, ESTs, cDNA and RNA-Seq data. Collecting those data and mer...学位:工学硕士院系专业:信息科学与技术学院_系统工程学号:2322012115305
遵从抑或解释:公司环境信息披露研究综述
随着经济发展模式从更多地生产转向可持续生产,公司环境信息披露正成为重要的政策工具。当前的公司环境信息披露实践主要表现为自愿性披露,相关的理论主要分为强调解释性质的经济披露理论,以及强调遵从性质的社会政治理论两个流派。在此基础上,近年的实证研究集中在公司环境信息披露与公司环境绩效之间的关系、公司环境信息披露的经济后果等领域。通过对公司环境信息披露的起源、定义、方式、动因和后果进行系统综述,罗列代表性的观点和证据,从而对该领域的研究逻辑进行梳理,并提出评论和展望,以利于更好地理解自愿性公司环境信息披露行为,促进相关的制度设计和理论发展。国家自然科学基金面上项目“污染型企业环境信息披露与融资动机及其后果”(71272081);中央高校基本科研业务费专项资金资助项目(20720151184
General Life Satisfaction and Self-esteem of University Students
目的 :研究大学生的一般生活满意度及其与自尊的关系。方法 :运用一般生活满意度量表和自尊量表对 12 0名大学生进行测试。结果 :本组大学生的一般生活满意度总体处于中等水平 ,其中女生平均分为 4 3 1,男生平均分为 3 65 ,女生生活满意度显著高于男生 (t =3 2 1,P <0 0 1) ; 来自城市学生的平均分为 4 3 0 ,来自农村学生的平均分为 3 67,城市学生生活满意度显著高于农村学生 (t =3 0 6,P <0 0 1)。12 0名大学生的自尊总均分约 3分 ,属较高水平 ,女生高于男生 ,城市大学生高于农村学生但差异不显著。高自尊组学生生活满意度高于低自尊组学生。结论 :大学生对现在的生活中等程度满意 ; 其生活满意度存在性别和地区差异。自尊水平高的大学生 ,其生活满意度亦比较高
Capacity Modulation Device with Changing Concentration of Mixture Refrigerant:A State-of-the-art Review
Air source heat pump is widely used, and a capacity modulation with concentration of mixture refrigerant is a new type modulation of environment protection and energy conservation. In this paper, the state of the art of existing variable concentration devices with mixture refrigerant is presented and their types are described according to their locations in the system. The analysis results indicate that the variable concentration device should be set at the outlet of liquid refrigerant in order to change concentration of mixture refrigerant in air source heat pump. Moreover, a rectification section is more effective to change concentration than a gasliquid separator or liquid reservoir, and the middle throttling apparatus should be an electronic regulation device other than a capillary tube. The improvement and application of variable concentration devices in air source heat pumps are also discussed
Research Progress on SiCBased Composite Ceramic Prepared Through a SingleSourcePrecursor Route
在碳化硅(SiC)陶瓷中引入异质元素可赋予其更优异的性能,如良好的热稳定性和独特的电磁性能。采用单源聚合物先驱体法制备陶瓷,通过合成不同结构的单; 源聚合物先驱体,可在原子尺度设计、调控陶瓷的组成和微结构等方面,达到优化陶瓷性能的目的。根据近年来的研究成果,介绍了单源聚合物先驱体制备Si-B; -C、Si-M-C (M=Ti, Zr, Hf)和Si-M-C (M=Fe, Ni)复相陶瓷的研究动态,并展望了其今后的发展趋势。The introduction of heterogeneous elements into SiC ceramics can endow; the ceramics with more excellent performances, such as high temperature; stability and unique electromagnetic properties. When preparing ceramics; through a single-source-precursor route, the composition and; microstructure of ceramics can be designed and tailored by tuning the; architecture of single-source-precursors at the atomic scale for; optimizing the ceramic performance. The research trends on Si-B-C,; Si-M-C (M = Ti, Zr, Hf) and Si-M-C (M=Fe, Ni) ceramic composites derived; from a single-source-precursor route were elaborated according to the; research achievements in recent years, meanwhile, its development trend; in the future was discussed.福建省自然科学基金; 华侨大学2016年实验教学改革与建设课
环孢素A微乳巴布膏眼贴的制备及体外透皮实验
背景:免疫性眼病如甲亢性突眼、葡萄膜炎等疾病严重危害患者的眼健康,是眼科的常见病和疑难病,目前最常见的治疗方法为口服激素和免疫抑制剂,疗效不佳、反复发作、预后差同时全身不良反应很大。此类疾病多有淋巴细胞直接或间接参与。尝试把免疫抑制剂制作成巴布膏眼贴,通过局部外用使药物进入体内,利用环孢素A微乳的淋巴靶向性能,使环孢素A作用在睑周淋巴结,从而达到治疗或控制睑周淋巴结参与反应的免疫性眼病。这种方法为局部外用,不用全身用药,针对性强,药物剂量小,如果治疗效果好,可以有效治疗免疫性眼病并规避原有药物全身应用及长期应用的不良反应。目的:制备环孢素A微乳巴布膏眼贴,研究环孢素A微乳巴布膏眼贴体外透皮吸收特性。方法:将环孢素A微乳与聚丙烯酸钠、聚乙烯醇、聚乙烯吡络烷酮、明胶、桃胶、羧甲基纤维素钠、羟丙基纤维素等的水溶性高分子材料混合物以1 mg∶1 mL的比例充分混匀,涂布于无纺布上制备成巴布膏。Franz扩散池法测定该巴布膏在ICR小鼠腹部皮肤的通透性。高效液相色谱分析法检测环孢素A浓度,并进行皮肤刺激性和过敏性实验。结果与结论:实验成功制备了粘性适宜、透气透水性能良好、敷贴舒适、无皮肤刺激性和过敏反应的环孢素A微乳巴布膏,环孢素A含量为10 mg/片,质量浓度为1 g/L。环孢素A微乳透皮的浓度随着时间的增加而增加,具有较好的透皮效果。证实将环孢素A微乳制备成巴布膏眼贴是可行的。其在透皮性能、黏附能力、皮肤舒适方面表现良好。莆田学院校级课题(2014034);;莆田市科技局课题(2014S06(2))~
基于CUMS模型探究抑郁症对细菌感染的影响及作用
目的抑郁症是一种常见的精神疾病,对患者的身体健康有着深远的影响。抑郁症与较高的细菌感染风险相关;然而,这是否是一种因果关系,以及抑郁症如何影响感染仍不清楚。因此,本研究旨在通过构建慢性不可预测轻度应激(CUMS)模型,探究抑郁表型在小鼠细菌感染中的作用。方法小鼠经CUMS诱导4周,通过行为学测试评估抑郁表型。随后,小鼠腹腔注射肺炎克雷伯菌模拟细菌感染,感染后48 h收集血清和腹腔组织。苏木精-伊红染色( HE)观察组织病理学改变,酶联免疫吸附试验(ELISA)检测炎性因子水平。此外,对感染前收集的小鼠粪便样本进行肠道菌群16S rDNA基因测序分析,并检测未感染小鼠结肠组织中NF-κB/NLRP3信号通路的表达水平。结果行为学测试结果显示,与对照组相比,CUMS小鼠体质量显著降低(P<0.000 1, t=5.426),蔗糖偏好率显著降低(P<0.001, t=4.937),游泳静止时间显著增加(P<0.001, t=16.37),旷场中央区域停留时间显著减少(P<0.01, t=3.575)。生存分析显示,与对照组小鼠相比,感染后CUMS小鼠的生存率显著降低(P<0.05)。HE染色结果显示,CUMS小鼠肝脏(P<0.05, t=4.025)、肾脏(P<0.05, t=2.828)、肠系膜(P<0.01, t=5.367)组织损伤程度明显加重。ELISA结果显示,炎症因子IL-6(P<0.01, t=3.365)、IL-1β(P<0.01, t=4.061)、TNF-α(P<0.01, t=4.460)和LPS(P<0.000 1, t=27.24)水平升高。16S rDNA测序结果显示,CUMS小鼠肠道菌群结构发生改变,与对照组小鼠明显不同,表现出菌群失调。与对照组相比,CUMS小鼠结肠组织中NF-κB(P<0.01, t=6.825)和NLRP3(P<0.001, t=9.561)的表达水平升高。结论CUMS小鼠发生更严重的细菌感染。CUMS诱导的抑郁表型可能因为破坏肠道菌群组成和激活NF-κB/NLRP3信号通路,增加了小鼠对细菌感染的易感性
Influence of dicarboxylic acids on self-assembly process: Syntheses and structural characterization of new Ag(I) complexes derived from mixed ligands
通讯作者地址: Huang, RB (通讯作者), Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China
地址:
1. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China
2. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China
电子邮件地址: [email protected] the principle of crystal engineering, three new silver metal–organic coordination polymers, [Ag2(L1)2(L2)]·2H2O (1), [Ag2(L1)2(L3)]·H2O (2), [Ag2(L1)2(L4)]·2H2O (3) (L1 = 2-aminopyrimidine, L2 = oxalate anion, L3 = glutarate anion and L4 = 1,4-naphthalenedicarboxylate anion) have been synthesized by solution phase reactions of silver nitrate with various dicarboxylic acids and cooperative heterocyclic 2-aminopyrimidine ligand under the ammoniacal conditions. All the complexes have been characterized by elemental analyses, IR spectra and X-ray diffraction. In complex 1, L1 ligands are coordinated to Ag(I) metal centers in rare tridentate fashions, forming one-dimensional (1-D) ladder-like structure, which is interlinked by L2 anions to generate 2-D pleated molecular sheet. Complex 2 displays an interesting two-dimensional (2-D) tongue-and-groove structure containing a new kind of “T-shaped” unit. Meanwhile, each of 2-D bilayers is interlocked by four adjacent identical motifs to form three-dimensional (3-D) 5-fold interpenetrating conformation with weak Ag···Ag interactions. In complex 3, L1 ligands are coordinated to the Ag(I) ions to form 1-D polymeric chain. And L4 anions, acting as bridging linkers through corresponding μ2-carboxylates, link a pair of Ag(I) atoms from adjacent chains to yield 3-D supramolecular network. The structures of complexes 1–3 which span from 2-D to 3-D networks suggest that dicarboxylate anions play important role in the formation of such coordination architectures.National Natural Science Foundation of China 20721001
973 Project, MSTC 2007CB81530
The Arc-forwarding Index and Wavelength Assignment Problem of All Optical Networks
光纤网络是当今及未来信息网络的核心技术之一,主要适用于可视电话、远程教育、远程医疗、家庭办公等新型业务。光纤网络可用一个弧对称(即图中有一条从u到v的弧当且当存在一条从v到u的弧)的有向连通图表示,其路由集是满足所有业务需求集的有向传输路径的集合。给定一个路由集R,其点(或弧)负载指标(ForwardingIndex)定义为R中通过每个顶点(或弧)的路径数目的最大值。进一步地,图G的点(或弧)负载指标为满足业务需求集的所有可能路由集的点(或弧)负载指标的最小值,记为(或)。光网络中的路由问题(TheRoutingProblem)是指构造一个路由集,使得此路由集的弧负载指标达到最少。给定网络的一...Optical network is emerging as key technology in communication networks and is expected to dominate many applications, such as video conference communications, scientific visualization, real-time medical imaging, high-speed super-computing and distributed computing. An optical network is defined as a symmetric directed(i.e., there is an arc from a vertex u to v if and only if there is an arc from ...学位:理学硕士院系专业:数学科学学院数学系_应用数学学号:20032304
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