微波合成SrTiO3的工艺、结构与性能研究

应用微波会成这一材料合成新方法制备SrTiO3，研究了不同工艺条件下微波合成产物的结构，确定出制备纯净SrTiIO。的合成条件．对微波合成的工艺及其影响因素进行详细的探索，从合成产物的显微结构、粒度分布、比表面积、烧结性能等方面比较了微波合成与常规固相合成的差别，结果表明微波合成与各种常规方法相比有合成时间短、合成工艺简单、合成产物性能好等特点，是一种有发展潜力的材料合成技术．     

第二代氨合成催化体系——钌系氨合成催化剂及其工业应用*

本文综述了第二代氨合成催化体系——钌系氨合成催化剂的研制、开发及工业应用情况。介绍了钌系氨合成催化剂的载体、促进剂、钌活性前身物对氨合成催化活性的影响。比较了钌系氨合成催化剂与铁系氨合成催化剂的反应机理与性能特点。新型氨合成催化工艺流程的成功开发为钌系氨合成催化剂的工业应用提供了有力的保障。     

绿色合成--21世纪的有机合成

绿色合成,作为当代有机合成发展的一个重要学科前沿,已成为化学发展的一个方向.从催化剂、绿色溶剂、合成手段、合成方法、计算机辅助绿色合成等方面综述了近年来国内外实现绿色合成的有效途径,并对绿色合成的目标进行了探讨.参考文献35篇.     

硫脲及其席夫碱衍生物合成与应用研究进展

硫脲类化合物因其独特的分子结构、良好的理化性能以及广泛的生物活性,在材料、医药、农药和配位催化等领域有重要的应用。因而其合成方法受到广泛关注。近年来,微波合成、超声波合成、无溶剂合成、离子液合成、相转移催化合成等一系列高效、绿色的合成方法在硫脲类化合物的合成中得到广泛的应用。结合本课题组的研究成果,本文着重综述了硫脲和席夫碱类化合物的合成方法及其应用,并对今后的研究方向进行了展望。     

SAPO分子筛的合成及影响因素的研究进展

本文综述了SAPO分子筛的主要合成方法,包括水热合成法、气相晶化法、液相晶化法、微波合成法、变温陈化法、超声合成法、程序升温法等方法.讨论了反应物的组成、模板剂、酸碱度、介质、晶化温度、晶化时间等因素对SAPO分子筛合成的影响.最后对SAPO分子筛合成方法进行了展望.     

药物中间体电合成技术的研究与应用

综述了药物中间体电合成技术的研究，从直接电合成、间接电合成、成对电合成及超声电合成法四个方面介绍了电合成技术在药物中间体合成中的应用。参考文献43篇。     

离子热法合成分子筛的研究进展

离子热法是以离子液体或低共熔混合物为介质的一种新型的分子筛合成方法, 它提供了一种离子态的独特合成环境, 为合成新型分子筛及研究分子筛的生成机理提供了机会. 本文综述了离子热法在分子筛合成方面取得的一些进展, 包括合成方法的创新、合成机理的研究、新材料的合成以及新型催化剂的制备等, 并展望了其发展前景.     

咪唑及其衍生物的合成研究进展

咪唑及其衍生物作为药物中间体,在生物学、医学、有机化学中占据重要位置.目前咪唑的合成方法主要包括Radziszewski法、Phillips法、溴乙醛法.咪唑衍生物的合成方法主要包括金属催化剂合成法、酸性催化剂合成法、离子液体催化剂合成法等.本文对咪唑及其衍生物的合成方法进行了总结与归纳,并阐述了各种方法的优缺点.     

肉桂酸的逆合成分析、合成设计及实验制备——一次设计型实验课的探索

以肉桂酸为目标产物,通过逆合成分析、合成设计,采用不同的实验方法合成制备,介绍了水相Heck反应、无溶剂Perkin反应、水相Wittig反应、水相Knoevenagel反应,拓展了学生的合成设计思维。本实验涵盖了目标产物的合成、纯化与表征,让学生认识和完成了一个基本的科研过程,提高了学生的综合能力。     

抗肿瘤药物仑伐替尼合成研究进展

综述了仑伐替尼及其相关主要中间体的合成方法。首先对仑伐替尼逆合成分析,并着重讨论了喹啉环(原料1)以及终产物仑伐替尼的合成。原料1有四种合成方法,对这四种合成方法进行了详细对比与分析,指出第二种合成方法为最佳合成方法。总结了仑伐替尼最常用的两条合成路线并分析优缺点,第一条路线是汇聚式路线,反应时间短、能耗少、成本低、收率高,相比第二条路线更加适合工业化生产。     

藻胆体核心复合物结构与功能的研究(Ⅱ)──4种变藻蓝蛋白复合物发色团相互作用机制

从螺旋藻藻胆体中分离出4种不同结构和光谱形式的变藻蓝蛋白复合物APⅠ、APⅡ、APⅢ和APB, 利用吸收光谱、荧光光谱比较了三聚体和单体的光谱特性, 通过对吸收光谱的光谱解曾以及各组分的归属, 研究了变藻蓝蛋白复合物内各色团间相互作用的性质和在能量传递中的功能.结果表明, 复合物内色团间的作用关系可以用Forster偶极-隅极作用机制来解释, 由于连接蛋白和同源亚基的存在影响其结构的对称性, 进而影响各色团间相互作用的形式和性质.     

ALLOPHYCOCYANIN FORMS ISOLATED FROM NOSTOC SP. PHYCOBILISOMES*

Abstract— Allophycocyanin from dissociated phycobilisomes of Nostoc sp. occurs in three spectrally identifiable forms that fractionate on calcium phosphate adsorption chromatography as: allophycocyanin (APC) I (15–20%), APC II (4&50%), and APC III (30–40%). APC I has a single absorption maximum at 654 nm, and a fluorescence emission peak at 678 nm. The absorption peaks of APC II and III are both at 650 nm, but the relative absorbance at 620/650 nm of APC III is less than that of APC II. The emission of both is maximum at 660 nm. On zone sedimentation in sucrose, their S_20,w values of 6.0 ± 0.1 (APC I), 5.0 ± 0.1 (APC II), and 5.3 ± 0.2 (APC III) were comparable to the order of their elution from Sephadex G-200. On SDS acrylamide gel electrophoresis two subunits were resolved with apparent molecular weights of 16,900 and 18,400 daltons. When stained by Coomassie blue, they were present in a ratio of 1α:1β in APC II and III, and a probable ratio of 2a:3β in APC I. The larger size of APC I may be accounted for by additional β subunits, by the presence of an additional polypeptide of 35,000 daltons, or both. Over several days, bleaching as noted by a decrease in absorbance at 650 nm, occurred in all three forms; in addition, the more pronounced bleaching at 650 nm, relative to 620 nm, results in APC III becoming spectrally identical to APC II. A trace of a fourth pigment, probably comparable to allophycocyanin-B, was occasionally detected. The results suggest that several in vitro APC forms (sharing similar subunits) arise upon phycobilisome dissociation, and that APC I is the form most closely related to the final fluorescence emitter of intact phycobilisomes. In this form it probably serves as the bridging pigment in energy transfer from the phycobilisomes to chlorophyll.     

ZnMoO4/芦荟衍生多孔碳的化学共沉淀法制备及催化性能

通过两步活化和化学共沉淀法分别制备了芦荟衍生多孔碳(aloe-derived porous carbon,APC)、ZnMoO₄和ZnMoO₄/APC催化剂,并研究了3种催化剂作为染料敏化太阳能电池(dye-sensitized solar cells,DSSCs)对电极时在D35/Y123染料和Cu²⁺/Cu⁺体系中的电化学特性和光伏性能。通过场发射扫描电子显微镜(FESEM)、X射线光电子能谱(XPS)和N₂吸附-脱附测试表征了APC、ZnMoO₄和ZnMoO₄/APC的微观结构、化学成分、比表面积和孔结构。结果表明:APC为多孔网络结构,比表面积为1439 m²·g^-1,ZnMoO₄纳米颗粒均匀嵌入或分散在APC表面。ZnMoO₄/APC在D35或Y123染料和Cu²⁺/Cu⁺电解液的DSSC中,分别获得了3.97%和3.72%的光电能量转化效率(power conversion efficiency,PCE),高于同等条件下的APC(2.72%,2.61%)、ZnMoO₄(1.24%,1.08%)和Pt电极(2.86%,2.80%)的PCE。     

Effects of PAR and UV Radiation on the Structural and Functional Integrity of Phycocyanin,Phycoerythrin and Allophycocyanin Isolated from the Marine Cyanobacterium Lyngbya sp. A09DM

An in vitro analysis of the effects of photosynthetically active and ultraviolet radiations was executed to assess the photostability of biologically relevant pigments phycocyanin (PC), phycoerythrin (PE) and allophycocyanin (APC) isolated from Lyngbya sp. A09DM. Ultraviolet (UV) irradiances significantly affected the integrity of PC, PE and APC; however, PAR showed least effect. UV radiation affected the bilin chromophores covalently attached to phycobiliproteins (PBPs). Almost complete elimination of the chromophore bands associated with α‐ and β‐subunit of PE and APC occurred after 4 h of UV‐B exposure. After 5 h of UV‐B exposure, the content of PC, PE and APC decreased by 51.65%, 96.8% and 96.53%, respectively. Contrary to PAR and UV‐A radiation, a severe decrease in fluorescence of all PBPs was observed under UV‐B irradiation. The fluorescence activity of extracted PBP was gradually inhibited immediately after 15–30 min of UV‐B exposure. In comparison to the PC, the fluorescence properties of PE and APC were severely lost under UV‐B radiation. Moreover, the present study indicates that UV‐B radiation can damage the structural and functional integrity of phycobiliproteins leading to the loss of their ecological and biological functions.     

Proteomic analysis of the small intestine and colon epithelia of adenomatous polyposis coli gene-mutant mice by two-dimensional gel electrophoresis

Mutations of the adenomatous polyposis coli gene (APC) have been implicated in the occurrence of sporadic colon cancer. Various APC mutant strains of mice have been created to better understand the function of this gene. Previously, we had mice express a mutant form of mRNA of the APC protein that encoded 474 amino acids instead of the 2845 amino acids due to exon duplication. These APC mutant mice (APC delta 474) developed intestinal and mammary tumors, as have other APC mutant mice previously reported (Sasai, H., et al. Carcinogenesis, in press). To elucidate the mechanism of the tumor development, we prepared protein samples from both normal and tumor tissues from APC delta 474 mutant mice, as well as tissues from normal mice, and used them for proteomic analysis. After two-dimensional electrophoresis, the gels were silver stained and the protein spots were analyzed. We analyzed about 1000 protein spots per sample and found several protein spots that are specific for normal or tumor samples from APC delta 474 mutant mice, as well as proteins with altered expression levels. Among the identified protein spots, truncated beta-tubulins were specific to APC delta 474 mutant mice polyp samples. The apparent molecular mass of these proteins suggested that these beta-tubulins may be truncated very close to the binding site of the anti-tumor drug taxol.     

Design and synthesis of novel type VI-like β-turn mimetics. Diversity at the i+1 and the i+2 position

In this paper, a synthetic approach for functionalised 5-aminopiperidinone-2-carboxylate (APC) systems as non-pro cis-peptide bond containing external β-turn mimics is presented. The scope and limitations of the synthetic method are discussed and the potential turn inducing properties of a model compound are evaluated by means of molecular modelling and NMR analysis.     

半刚性乙酰氧丙基纤维素的制备与液晶相转变的影响研究

以羟丙基纤维素为原料,通过酯化反应合成了分子量较高的乙酰氧丙基纤维素,并用ＦＴ－ＩＲ表征了化学结构。以ＤＳＣ,Ｘ－ｒａｙ衍射ＰＬＭ和ＳＡＬＳ手段研究了产物的热致液晶相转变及其影响因素和溶致液晶性。实验表明,产物的乙酰基含量受合成温度和反应时间影响,其热致液晶的相转变温度和温域随乙酰基含量变化。     

Antioxidant properties of recombinant allophycocyanin expressed in Escherichia coli

Allophycocyanin (APC) is the main core component of phycobilisome found in blue-green algae. The apo-allophycocyanin and its subunits were expressed in Escherichia coli and their antioxidant properties were evaluated using deoxyribose assay. The result showed that both recombinant allophycocyanin fused with maltose binding protein (MBP) tag and 6 x His-tag and their alpha or beta subunits can scavenge hydroxyl radicals successfully, and the separated alpha or beta subunits had a higher inhibition effect on hydroxyl radicals than that when they combined together. The scavenging effects increased with the increasing concentration. These results clearly suggested that apo-allophycocyanin is involved in the antioxidant and radical scavenging activity of phycocyanin, and the antioxidant activity may be partially responsible to the anti-tumor effect of the recombinant allophycocyanin.     

Conformational Selection Mechanism Provides Structural Insights into the Optimization of APC-Asef Inhibitors

Metastasis is the major cause of death in colorectal cancer and it has been proven that inhibiting an interaction between adenomatous polyposis coli (APC) and Rho guanine nucleotide exchange factor 4 (Asef) efficaciously restrain metastasis. However, current inhibitors cannot achieve a satisfying effect in vivo and need to be optimized. In the present study, we applied molecular dynamics (MD) simulations and extensive analyses to apo and holo APC systems in order to reveal the inhibitor mechanism in detail and provide insights into optimization. MD simulations suggested that apo APC takes on a broad array of conformations and inhibitors stabilize conformation selectively. Representative structures in trajectories show specific APC-ligand interactions, explaining the different binding process. The stability and dynamic properties of systems elucidate the inherent factors of the conformation selection mechanism. Binding free energy analysis quantitatively confirms key interface residues and guide optimization. This study elucidates the conformation selection mechanism in APC-Asef inhibition and provides insights into peptide-based drug design.     

Localization of noncovalent complexes in MALDI-preparations by CLSM

The unambiguous detection of noncovalent complexes (NCCs) by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is still a far cry from being routine. For protein NCCs such as their quaternary structure it has been reported that signals of the intact complex are only obtained for the first or at most the first few laser exposures of a given sample area. This observation was called the first-shot phenomenon. In the present study, this first-shot phenomenon has been investigated for the hexameric protein complex allophycocyanine (APC) by two independent methods, MALDI-MS with a (nearly) pH-neutral matrix 6-aza-2-thiothymine (6-ATT) and by imaging the fluorescence of the complex in APC-6-ATT preparations by confocal laser scan microscopy (CLSM). The intact APC heterohexamer loses its visible fluorescence upon dissociation into its subunits. Both methods consistently show that intact APC complexes are precipitated at the matrix crystal surface, but dissociate upon incorporation into the matrix crystals.