[Poly(styryl)phenanthroline]palladium as heterogeneous catalyst for heck arylation using iodobenzene

The effects of different bases on Heck arylation catalyzed by the polymeric catalyst

have been studied. The yield of product and the lifetime of the catalyst are influenced by the nature of the base used. The leaching of palladium from the polymeric catalyst is caused mainly by the competitive complexation of the ligands existing in the reaction media towards the metal. When tributylamine is replaced by DMF-H₂O-NaOAc, the catalyst can be easily recovered and reused, the yields are higher and the products are found to be more pure. For the reaction of acrylamide with iodobenzene, even after ten consecutive runs the recovered catalyst still has high catalytic activity. In the DMF-H₂O-NaOAc system, the catalyst can also tolerate the presence of a variety of functional groups; acrylamide could be introduced to react with substituted iodobenzenes in good yields.     

4种不同酵母酿造杨梅酒的风味特征差异分析

目的 探究3种商业酿酒酵母(DV10、D254、X16)及1种从杨梅醪中筛选的原生酵母(CCTCC M2015627)酿造杨梅酒的风味特征差异。方法 通过顶空固相微萃取-气相色谱-质谱法(headspace solid-phase micro-extraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)检测不同酵母发酵杨梅酒的挥发性香气物质,通过计算相对气味活性值(relative odor activity value,ROAV)确定重要香气活性化合物,根据变量重要性投影(variable importance in projection,VIP)值筛选关键差异特征呈香物质。结果 4种酵母发酵杨梅酒共鉴定出107种挥发性成分,其中原生酵母发酵的杨梅果酒香气物质种类总数最多,为93种,X16杨梅酒香气物质类别丰富度最低,为62种,DV10及D254杨梅酒产香物质类别丰富度居中。DV10杨梅酒香气物质总含量最高,且ROAV≥0.1的香气活性成分最多,为17种。ROAV≥1的物质为异丁酸乙酯、丁酸乙酯、乙酸异戊酯、正己酸乙酯,...     

Kinetic parameter estimation for cooling crystallization process based on cell average technique and automatic differentiation

In this paper, a cell average technique(CAT) based parameter estimation method is proposed for cooling crystallization involved with particle growth, aggregation and breakage, by establishing a more efficient and accurate solution in terms of the automatic differentiation(AD) algorithm. To overcome the deficiency of CAT that demands high computation cost for implementation, a set of ordinary differential equations(ODEs) entailed from CAT based discretized population balance equation(PBE) are solved by using the AD based high-order Taylor expansion. Moreover, an AD based trust-region reflective(TRR) algorithm and another interior-point(IP) algorithm are established for estimating the kinetic parameters associated with particle growth, aggregation and breakage. As a result, the estimation accuracy can be further improved while the computation cost can be significantly reduced, compared to the existing algorithms. Benchmark examples from the literature are used to illustrate the accuracy and efficiency of the AD-based CAT, TRR and IP algorithms in comparison with the existing algorithms. Moreover, seeded batch cooling crystallization experiments of β form L-glutamic acid are performed to validate the proposed method.     

Optical studies of Y_3(Al,Ga)_5O_(12):Ce~(3+),Cr~(3+),Nd~(3+) nano-phosphors obtained by the Pechini method

The Y3(AI,Ga)_5O_(12):Ce~(3+),Cr~(3+),Nd~(3+)(YAGG) nano-phosphors with homogeneous particle-size distribution,low aggregation and average crystalline size of about 65 nm were obtained using a modified Pechini method.Only slight aggregation of the crystallites occurs after post-annealing at 1100℃.The intense Ce~(3+)bands in the excitation spectra of the Ce~(3+),Cr~(3+),Nd~(3+)co-doped materials monitoring the Cr~(3+) emission at 690 nm indicate energy transfer from Ce~(3+) to Cr~(3+).Weak Nd~(3+) lines are observed,as well.In addition,the emission of Nd~(3+)at 1060 nm with excitation of Ce~(3+) and Cr~(3+) confirms the Ce~(3+)/Cr~(3+)to Nd~(3+)energy transfer.The short average luminescence decay times for the Ce~(3+) emission indicate the Ce~(3+)/Cr~(3+)to Nd~(3+)energy transfer.Eventually,the Y_3(AI,Ga)_5O_(12):Ce~(3+),Cr~(3+),Nd~(3+) nano-phosphors exhibit persistent luminescence originating from the 4f~3→4f~3 transitions of Nd~(3+) which matches well to the first biological window to be used in bioimaging applications.     

The ALEPH minivertex detector

Vertex detectors allow high precision reconstruction of particle tracks and therefore make possible the investigation of the decay topology of short-lived particles in collider experiments.In the ALEPH experiment at LEP a minivertex detector will be installed. It consists of silicon microstrip detectors arranged on two concentric “cylindrical” surfaces around the interaction point. With this geometry it will be possible to measure the r − ϕ − z coordinates of particles traversing the detector. The expected position resolution is 10 μm in r − ϕ and 20 μm in r − z.For optimum signal processing monolithic CMOS readout electronics are under development. Each chip consists of 60 charge sensitive preamplifiers, multiplexed into one output channel. Fast power switching will reduce heat dissipation.Details about construction and expected device performance will be described.     

Characterization of four diol dehydrogenases for enantioselective synthesis of chiral vicinal diols

Enantiopure vicinal diols are important building blocks used in the synthesis of fine chemicals and pharmaceutical compounds. Diol dehydrogenase(DDH) mediated stereoselective oxidation of racemic vicinal is an efficient way to prepare enantiopure vicinal diols. In this study, four new bacterial DDHs(AnDDH from Anoxybacillus sp. P3 H1 B, HcDDH from Hazenella coriacea, GzDDH from Geobacillus zalihae and LwDDH from Leptotrichia wadei) were mined from the GenBank database and expressed in E. coli T7...     

Anti-Staphylococcal Activity of Eugenia Jambolana L. Against Methicillin–Resistant Staphylococcus Aureus

The antibacterial activity of ethanol extracts of Eugenia jambolana L. and E. uniflora L. (Myrtaceae) were evaluated by agar-well diffusion method and MICs by microdillution method. E. jambolana showed antibacterial activity against MRSA strains (MIC < 1024 μg/mL). E. uniflora did not show significant antibacterial activity (MIC > 1024 μg/mL). It is therefore suggested that extracts from E. jambolana could be used as an anti– Staphylococcus agent. When compared with Methicillin and Gentamicin, the extract was more effective against, being a promising antibacterial agent. Based on the author's knowledge, this is the first report about the antibacterial activity of leave ethanol extract from Eugenia jambolana.     

利用TAIL-PCR克隆Gluconobacter suboxydans葡萄糖脱氢酶基因及其生物信息学分析

以Gluconobacter suboxydans J菌株基因组DNA为模板,基于吡咯喹啉醌附着位点的保守区域设计引物,通过交错式热不对称PCR获得编码葡萄糖脱氢酶（glucose dehydrogenase,GDH）的全长基因（gdh）,并对其序列进行生物信息学分析。结果表明：gdh基因全长2 268 bp,编码755个氨基酸,其蛋白序列与Gluconobacter属的GDH具有较高的同源性。GDH的分子质量约为81.72 ku,pI值约为5.14;GDH蛋白的二级结构由18.41%的α-螺旋、16.16%的延伸和65.43%的无规则卷曲3种结构模块组成;GDH N末端的AA 1～140区域有5个跨膜结构域。     

金银花泡腾饮料片加工工艺的研究

以崩解时限、口感、澄明度等为考察指标,通过单因素实验及正交实验筛选金银花泡腾饮料片配方。实验表明,最佳配方为:金银花浸膏粉质量分数为40%,崩解剂用量为27%(由PEG6000包裹的碳酸氢钠与柠檬酸组成,重量比为1.3:1),32%乳糖为稀释剂,1%PEG6000为润滑剂。其中制粒时和制粒后加入的崩解剂比例为5:4。本法工艺可行、重现性好,所制得金银花泡腾片崩解性好,硬度符合要求,崩解后所形成的饮料澄明、口感好。