Plasmonic sensing of CTAB in gold nanorods solution based on Cu(II) ions-mediated H2O2 etching effect

Controlled release formulation of pesticides is highly desirable for attaining the most effective utilization of the pesticide as well as reducing environmental pollution. Nano-sized controlled release formulations can provide better penetration through cuticle and deliver the active ingredients efficiently to the targeted tissue. In this study, a novel strategy for the preparation of a nanoconjugate derived from kasugamycin with amino-modified silica was developed. The kasugamycin was connected with amino-modified silica matrix by an amide bond, which could avoid the initial burst release effectively and prolong the duration remarkably. The results showed the kasuga-silica can protect kasugamycin against photo-degradation effectively and the release rate of the active ingredient of nanoconjugate was related to the temperature, pH value, and the particle size (52.5–315.4 nm). With reduced particle size as well as increased temperature and acidity, the release of the active ingredient was faster. This amide linkage of kasuga-silica could be degraded by amidase effectively. This nanoconjugate displayed a better and a sustained bactericidal efficacy against E. coli than kasugamycin technical, which makes it a potential candidate as a controlled release conjugate for kasugamycin in the future.     

Failure Processes in Fiber-Reinforced Liquid-Crystalline Polyester Composites

A hierarchical structural model for liquid-crystalline polyester reinforced with short glass fibers has been determined by using injection-molded bars. The gradient structure showed similar orientations between the glass fibers and the molecular orientation of the matrix. In the fiber-reinforced composites, the core failed prior to the skin by matrix cracking and transverse fiber pull-out as evidenced by the initial growth of parabolic cracks in the core. In the 30 wt% composite this was followed by complex cooperative phenomena involving fiber breakage, debonding, pull-out, and matrix deformation in the skin. The 50 wt% composite failed prematurely due to inadequate fiber/matrix interactions in the skin structure. Acoustic emission coupled with microscopy provided mechanistic insight throughout this work into the amount and intensity of specific failure mechanisms.     

高效液相色谱法测定榨菜中柠檬黄的不确定度评定

根据JJF1059～1999《测量不确定度评定与表示》对高效液相色谱法测定榨菜中柠檬黄含量的测定不确定度进行评定。通过对实验过程中样品的取样称量、使用仪器、标准物质、测试过程中的随机因素以及标准工作曲线的拟合等因素进行分析,计算了不确定度分量和合成不确定度。榨菜中柠檬黄含量的测定结果为（0．0375±0．0050）g／kg,k=2。     

微波消解–石墨炉原子吸收法测定化妆品中的铅

建立了微波消解–石墨炉原子吸收光谱法测定化妆品中铅的方法。探讨了样品前处理条件、基体改性剂的选择和优化、石墨炉升温条件等对测定结果的影响。在优化的试验条件下,铅的质量浓度在0~100 ng/mL范围内与吸光度具有良好的线性关系,线性相关系数r=0.9991,检出限为0.33 ng/mL。用该法对5种化妆品中的铅进行测定,加标回收率在95.0%~106.1%之间,测定结果的相对标准偏差不大于3.6%。该方法可应用于化妆品中痕量铅的分析。     

Direct Esterification of Carboxylic Acids with Alcohols Catalyzed by Iron(III) Acetylacetonate Complex

Direct condensation of carboxylic acids and alcohols with electronic, steric, and functional group variations was carried out using the environmentally benign, moisture-stable, inexpensive, and recoverable iron(III) acetylacetonate [Fe(acac)₃] as catalyst (5 mol%). This iron salt efficiently catalyzed the esterification of several primary and secondary alcohols in refluxing xylene, without the need for a dehydration reagent. The chemoselectivity of the proposed protocol was demonstrated by the selective esterification of primary alcohol functionality in racemic 1-phenylethane-1,2-diol with benzoic acid. The esterification was also applicable to unmasked α -hydroxyacid, guasiaromatic, heterocyclic, and N-protected amino acids.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.