Quantitative determination of soybean meal content in compound feeds: comparison of near-infrared spectroscopy and real-time PCR

Standard methods for determining the raw material content of compound feed are little exploited, except for the identification of meat and bone meal in feeds. In this work, near-infrared (NIR) spectroscopy and real-time polymerase chain reaction (PCR) were applied in order to establish new and fast methods for quantification of soybean meal content in compound feeds. The best prediction quality was achieved by using a model based on NIR spectroscopy (R ² = 0.9857, standard error of cross-validation 1.1065). Furthermore, a sensitive qualitative detection method by using the real-time PCR was developed (R ² = 0.976, slope −3.7599). Finally, the differences between the real-time PCR result and the NIR spectroscopy result for a given sample were also treated, and we found that the NIR spectroscopy method provided quite accurate results which approach closely those of the real-time PCR method. Hui Li and Xiaowen Lv contributed equally to this work.     

At-line coupling of UPLC to chip-electrospray-FTICR-MS

Since highly sensitive on-line coupling of UPLC with FTICR-MS is technically infeasible due to their different scan rates, at-line coupling of these techniques was developed for rapid analysis. To enable cutting of one peak of the chromatogram into one fraction, several conditions and relationships were investigated, e.g. the optimum volume of the inserted delay loop, the relationship between retention time, loop outlet drop speed, individual drop volume versus mobile phase composition under constant speed, and linear solvent strength gradient elution modes. Good and reproducible results were achieved applying UPLC as an efficient separation and fast fractionation tool before the FTICR-MS measurements. A chip-based nanoelectrospray ionization system was employed which was perfectly suited to handling the small-volume fractions and was thus chosen for the at-line coupling. The method was initially applied to spiked extracts of cell-free bacterial culture supernatants in which bacterial signalling compounds, namely N-acyl homoserine lactones (AHL), were detected. Good reproducibility and high recovery was observed. Afterwards, a culture supernatant of Erwinia sp. JX3.2, a putative AHL producer, was investigated and N-hexanoyl-homoserine lactone was determined as a possible signalling molecule. More reliable assignments were achieved by use of at-line coupling of UPLC and FTICR-MS compared with off-line measurements. Xiaojing Li and Agnes Fekete have contributed equally to this publication.     

高热值多面体硼氢化合物十氢十硼酸双四乙基铵的合成、热分解机理及动力学研究

以四氢硼酸四乙基铵为原料,通过热解反应合成了十氢十硼酸双四乙基铵,并采用红外光谱(IR),核磁共振波谱(1H NMR,11B NMR)及元素分析对其结构进行了表征.采用差热-热重(DSC-TG)分析研究了其在氩气及氧气气氛下的热稳定性,发现其在氩气中仅发生热分解反应,放热量较小,而在氧气中则先分解,再发生氧化反应并放出大量的热.采用Kissinger方法及Coat-redfern方程得到其热分解主反应的动力学方程,并进一步通过热裂解原位池-傅里叶变换红外光谱(FTIR)联用技术和同步热分析-红外-质谱(DSC-TGFTIR-MS)联用技术研究了其热分解机理,推测在加热升温过程中,化合物在303.2℃下快速分解,气相产物主要为乙烷与少量氨气及氢气,固相产物为单质硼.     

BODIPY-吡咯类荧光染料的合成及光谱识别性能

采用Knoevenagel反应以氟化硼配位二吡咯甲川类荧光染料BODIPY(4,4-difluoro-4-bora-3a,4adiaza-s-indacene)为母体,经吡咯甲醛或杯吡咯甲醛合成了四个BODIPY荧光染料1a~1d,用MS,NMR和元素分析进行结构确证。考察了它们的紫外吸收光谱与荧光发射光谱,结果表明1a~1d具有较高的摩尔吸光系数,在BODIPY母环的3,5位双取代物(1c和1d)相对于单取代物(1a和1b)其最大吸收波长和发射波长分别红移了约90nm和80nm,说明BODIPY-吡咯衍生物中共轭程度增强,光谱出现红移。阴离子识别研究表明,1b和1d能够与Cl-形成多重氢键,导致吸收光谱红移和荧光猝灭。     

Synthesis,Photophysics, and Self‐Assembly of Furan‐Embedded Heteroarenes

A series of pyrene/phenanthrene‐fused furan derivatives ( 1 – 8 ) were synthesized by a simple condensation reaction between pyrene‐4,5‐diketone/phenanthrenequinone and substituted phenol/naphthol in the presence of trifluoromethanesulfonic acid in 1,2‐dichlorobenzene heated at reflux. The formed compounds can emit strong blue light in organic solvents. Additionally, the self‐assembly behaviors of two of the compounds ( 3 and 5 ) were studied through re‐precipitation method and the resulting nanostructures were characterized by UV/Vis, fluorescence spectra, and field‐emission scanning electron microscopy (FESEM). The findings showed that the shape and size of compounds 3 and 5 could be tuned by the ratio of THF and hexadecyl trimethyl ammonium bromide (CTAB) solution in water.     

Dipeptidyl peptidase-IV activity assay and inhibitor screening using a gold nanoparticle-modified gold electrode with an immobilized enzyme substrate

Microchimica Acta - We report on an electrochemical biosensor for the determination of the activity of dipeptidyl peptidase-IV (DPP-IV), and on a method for screening the effect of its inhibitors....     

淀粉基聚合物胶束用作药物载体

两亲性聚合物能通过亲疏水作用自组装为核-壳结构,而这独特的优势已使其成为在肿瘤靶向药物缓释方面具有很好发展前景的药物载体.淀粉原材料来源丰富,价格低廉,同时具有良好的生物相容性和生物可降解性,故基于淀粉的两亲性聚合物胶束正引起越来越多研究者极大的关注.作为药物载体,淀粉基聚合物胶束不仅可以提高药物的水溶性、延长药物在体内的循环时间、降低副作用和通过增强渗透与滞留(EPR)效应提高药物在靶向部位的优先累积,还可以在淀粉骨架上引入一些刺激响应型的官能团实现胶束快速靶向释药的功能.因此,淀粉基聚合物胶束在用作药物载体方面有着广阔的发展潜力.本文结合本课题组目前的研究工作和近几年的相关报道对淀粉基聚合物胶束作为药物载体的最新研究进展做简要综述.     

ChemInform Abstract: First‐Principles Molecular Dynamics Investigation on Na3AlF6 Molten Salt.

The partial radial distribution function, coordination numbers, bond angles, F atoms type, self‐diffusion coefficient, viscosity, and ionic conduction of molten Na₃AlF₆ are investigated by first‐principles molecular dynamics simulation.