三联噻吩基查尔酮衍生物的线性光学性质和超快非线性光学响应北大核心CSCD

以α-三联噻吩甲醛为原料,与3种二氯苯乙酮发生Claisen-Schmidt缩合反应,合成了3种含有三联噻吩基的查尔酮衍生物:1-(α-三联噻吩-2-基)-3-(2,4-二氯苯基)丙烯酮(a)、1-(2,5-二氯苯基)-3-(α-三联噻吩-2-基)丙烯酮(b)和1-(3,4-二氯苯基)-3-(α-三联噻吩-2-基)丙烯酮(c)。借助核磁共振波谱仪(^(1)H NMR、^(13)C NMR)和液-质联用谱仪(LC-MS)对其结构进行了表征;采用Z-扫描技术(600 nm,180 fs)测定了3个化合物的非线性光学吸收性能;运用含时密度泛函理论(TD-DFT)方法计算了它们的极化率(α_(0))、静态第一超极化率(β_(0))、振子强度(f_(0))、跃迁能(ΔE)、基态和最主要激发态之间的偶极矩差(Δμ)、最主要激发态的主要组成、最高占据分子轨道(HOMO)和最低空分子轨道(LUMO)之间的能隙,同时测定了它们的线性光学性质。结果表明,化合物c的紫外吸收波长、荧光发射波长、热稳定性、极化率均最大;化合物a—c均存在分子内电荷转移现象,非线性吸收均为双光子吸收,化合物a、b还有五阶非线性吸收,它们均表现出超快非线性光学响应,可作非线性光学研究备选材料。     

第一性原理软件北京原子技术模拟工具包的重构进展

基于第一性原理的理论方法的研究,代表了材料计算、分子模拟等领域的科学高地,相应的第一性原理计算软件直接关系到该领域相关理论、算法的积累.本文汇报了我们在重构第一性原理计算模拟软件—北京原子技术模拟工具包(BSTATE)的一些最新进展.重构的核心思想是降低用户使用门槛、扩展软件适用范围、增加软件对于流行计算框架的支持.基于此思路,在BSTATE原有Makefile编译系统的基础上添加了CMake编译环境,并支持各种数学函数库的自动和交互式配置;通过在原有内置泛函基础上增添Libxc泛函库的支持,使BSTATE支持的泛函数量有了数量级上的增长;分析测试BSTATE在集群的并行特点,并以更新数学库接口(FFTW3、Cufftw)的形式提供对于流行异构框架的初步支持.     

梯形化合物NaV2O4F电子结构的第一性原理研究

采用基于密度泛函理论(DFT)的第一性原理赝势平面波方法, 通过自旋极化的广义梯度近似(GGA)电子结构计算对梯形化合物NaV₂O₄F进行了研究. 考虑了四种假想的自旋有序态,计算结果表明该化合物的磁基态具有二维反铁磁(AFM)结构, 即沿梯阶和梯腿方向都表现为AFM作用. 能带结构显示NaV₂O₄F为绝缘体材料, 带隙约为1.0eV. 方锥体中的晶体场劈裂使得VO₄F方锥体中的 V^{4+ 关键词： 2O₄F')" href="#">NaV₂O₄F 梯形化合物 第一性原理计算 电子结构}     

微波辅助提取壶瓶枣多糖及其抗氧化性

采用微波辅助法提取了壶瓶枣多糖,并对壶瓶枣粗多糖(CP)、脱蛋白多糖(DP)对·OH、O-2·和DPPH·3种自由基的清除作用进行了研究.结果表明:壶瓶枣CP和DP对3种自由基都有明显的清除作用,清除率与多糖浓度存在明显的量效关系.壶瓶枣CP和DP对·OH、O-2·和DPPH·的半清除率(IC50)值分别为0.2312、0.9326、0.1830mg/mL和0.5049、0.2016、0.0694mg/mL.CP清除能力为DPPH·＞· OH＞O-2·,DP清除能力为DPPH· ＞O-2·＞·OH.     

Comparative Metabolomic Study of Penicillium chrysogenum During Pilot and Industrial Penicillin Fermentations

Comparative metabolomics was carried out to investigate the metabolic differences of Penicillium chrysogenum in the pilot and industrial fermentations that resulted from the scale-up. By principal component analysis, the early stages of two fermentation processes were clearly distinguished, whereas the middle and final stages were clustered together. It indicated that the different metabolisms of cells in the pilot and industrial fermentations mainly existed during the early stage. Furthermore, the levels of polyamines, polyols, glycolysis, and tricarboxylic acid cycle intermediates, which changed more dramatically during the pilot process, were all higher in the pilot than in the industrial fermentation during the early stage. This indicated that the fermentation conditions of the early stage should be the focus of process management which is aimed at increasing penicillin production. Additionally, the comparative accumulations of the precursors of penicillin (valine, cysteine, and lysine) revealed that penicillin biosynthesis in the industrial process was more affected during the middle stage of fermentation. These findings provide new insights to further regulate the industrial process and improve the production of penicillin. More generally, this study attempts to address the scarcity of studies that contrast the metabolic outcomes between commercial- and pilot-scale conditions.     

烟草中多酚类化合物测定方法比较

研究了光谱法和色谱法测定烟草中的多酚含量。光谱法测出的多酚总量和色谱法测出的7种多酚分量存在一定的相关性,可决系数在0.0001—0.7297之间。通过逐步回归分析得到光谱法测得的多酚总量=5.8477+0.8220×绿原酸+2.4954×奎宁酸+0.4081×咖啡酸+1.0257×芸香苷。同一品种不同部位烟叶多酚含量不一样,光谱法测得上、中、下部位烟叶多酚含量分别为51.07、46.63、41.27mg/g。色谱法回收率在95.05%—106.80%之间,光谱法回收率为101.72%,色谱法相对标准偏差为1.64%—4.55%,光谱法相对标准偏差为2.86%。     

气相色谱-质谱对青霉素发酵中玉米浆潜在标志物的研究

基于气相色谱-质谱(GC-MS)结合正交偏最小二乘判别分析法(OPLS-DA),建立了筛选玉米浆中影响青霉素发酵效价的潜在标志物的方法.利用GC-MS获得玉米浆中44种物质,经过标准化、Pareto预处理后,通过OPLS-DA对样本进行模式识别,根据模型的载荷图和变量重要性因子(VIP)筛选出9个潜在的标志物,即亮氨酸、5-酮脯氨酸、天冬氨酸、柠檬酸、酪氨酸、丝氨酸、赖氨酸、苏氨酸和葡萄糖.结果表明,这些物质与青霉素的初级代谢和次级代谢密切相关,可以作为筛选青霉素发酵优质原料的潜在质量指标.     

基于组效关系的姜黄挥发油抗肿瘤活性成分辨识研究

基于GC-MS分析,建立了姜黄挥发油的化学成分与其抑制人宫颈癌Hela细胞作用的组效关系模型,寻找与药效显著相关的活性成分。采用水蒸汽蒸馏法提取得到31批姜黄挥发油,提取率在1.63%～4.52%之间;采用GC-MS联用仪建立了31批姜黄挥发油的指纹图谱,确定了20个特征峰,以特征峰的相对峰面积(各峰面积与内标正十三烷的峰面积之比)来表征其相对含量;MTT法测定姜黄挥发油抑制人宫颈癌Hela细胞活性,以抑制率为评价指标;利用Simca-p11.5软件的正交投影偏最小二乘法(Orthogonal Partial leastsquares,OPLS)和SPSS软件的双变量相关(bivariate)分析,研究特征峰与药效的相关性,根据S-载荷图、变异权重参数值(Variable importance in projection,VIP)和皮尔逊(Pearson)相关系数来辨识显著活性成分。结果表明,11,15,7,19,3,6,12,14,9号等9个特征峰与姜黄挥发油抑制Hela细胞活性显著相关,除19号峰尚未定性外,11,15,7,3,6,12,14和9号峰对应的成分分别为芳姜黄酮、β-姜黄酮、姜烯、β-榄香烯、α-姜黄烯、α-姜黄酮、吉马酮和β-倍半水芹烯。     

Biological responses of suspension cultures of Taxus chinensis var. mairei to shear stresses in the short term

The biological responses of Taxus chinensis var. mairei suspension cultures to a range of shear rates, were investigated in a Couette-type shear reactor. It was found that the shear rate below 458 s⁻¹ enhanced the primary metabolism, increasing mitochondrial activity and protein expression and inhibiting the activity of phenylalanine ammonia lyase (PAL), an enzyme relevant to the secondary metabolism. However, the shear rate over 719 s⁻¹ damaged taxus cells to some extent, decreasing the mitochondrial activity, increasing the membrane permeability, and even causing cell hypersensitive responses. As a result, PAL and intracellular peroxidase, an enzyme in cells relevant to reactive oxygen species scavenging, were activated and extracellular phenolics were accumulated. Additionally, shear-induced accumulation of free radicals and alkalization of the culture medium were observed. The results might shed light on a better understanding of the mechanism of plant cells responses to shearstress through the signal transduction pathway.     

青蒿二烯功能模块与酵母底盘的适配性

设计构建人工酿酒酵母细胞合成青蒿二烯的关键是使外源功能模块与底盘细胞适配,本文通过对外源功能模块中的载体、蛋白表达和启动子进行优化,以提高功能模块与底盘细胞的适配性. 使用着丝粒载体和附加型载体构建了2种青蒿二烯功能模块,在过表达甲羟戊酸（MEV）途径中关键基因（截短的3-羟基-3-甲基戊二酰辅酶A还原酶基因tHMGR及法尼基焦磷酸合酶基因ERG20）的2种酵母底盘中进行适配,得到适配性较好的人工合成细胞,其产量为11.2 mg/L;将青蒿二烯合酶基因（ADS）与ERG20进行融合构建融合蛋白功能模块,在选定底盘中适配性进一步提高,青蒿二烯的产量提升至17.5 mg/L;采用不同强度的启动子（TDH3p,TEF1p和PGK1p）对融合蛋白功能模块进行调控,最终得到功能模块与底盘间适配关系更好的人工合成细胞,其产量提升到71.8 mg/L.