Diarylpropane‐1,3‐dione Derivatives as TetR‐Inducing Tetracycline Mimetics: Synthesis and Biological Investigations

Synthesis, biological investigations and molecular docking studies of nonantibiotic and nontetracyclic inducers that feature a minimal key motif of the natural lead tetracycline are presented. The diarylpropane‐1,3‐dione motif was identified as the minimal substructure responsible for TetR induction by tetracyclines. The first nontetracyclic surrogates of the natural tetracyclines displayed significant inducing effects for TetR(BD)S135L, whereby the chlorohydroxyphenyl‐substituted β‐diketone 31 displayed the highest activity. Interestingly, antibiotic activity could not be detected for 31 . Homology modeling based on the X‐ray structure of 7‐chlorotetracycline bound to TetR indicated analogous binding modes for the natural inducer and the synthetic diarylpropane‐1,3‐dione derivatives.     

原油减压渣油馏分的油-水界面性质：Ⅷ．减渣馏分分子参数与其模拟乳状液的稳定性

采用相对分子质量测定、元素分析、紫外光谱和红外光谱等手段，确定了大庆减压渣油与伊朗重质减压渣油的分子参数，并考察了两个系列减压渣油馏分的模拟乳状液的稳定性。在此基础上，采用复合变量分析探讨了减压渣油馏分的各分子参数之间的关系，以及这些分子参数与模拟乳状液稳定性的关系。结果表明，减压渣油馏分不同的分子参数对其模拟乳状液稳定性的影响不同，其中馏分的相对分子质量、稠环芳香结构的含量、脂肪烃相对含量、羰基相对含量对模拟乳状液的稳定性影响最明显。一般情况下，馏分的相对分子质量越大、稠环芳香结构和羰基含量越高，则乳状液越稳定。     

Corn4并股线——织造完美织物的纱线

使用Rieter公司的Com4并股线纺纱方法纺制的天丝纱能够满足生产精致的印度莎丽服的高要求。从许多方面来说，这种莎丽服与采用100％丝织成的传统莎丽服性能相当，但从纤维与纱线的加工成本看，比丝制莎丽服更加经济。     

Applicability of highly reflective aluminium coil for solar concentrators

Because of their manufacturing flexibility and their low costs, mirrors based on anodized or coated sheet aluminium are a promising alternative as primary or secondary concentrators in a number of solar energy applications. They offer solar weighted reflectances of 88–91%, good mechanical properties and are easy to recycle. However, problems occur due to their limited corrosion resistance. Therefore, prior to application, lifetime tests including outdoor and accelerated ageing tests are necessary to prove their optical durability in terms of achieving a 10-year service lifetime. In this study the optical properties of a number of different aluminized reflector materials after accelerated and outdoor exposure tests have been investigated. Optical testing has been performed by measuring the spectral hemispherical reflectance of exposed samples and calculating the solar weighted value. Additionally, specular reflectance has been measured with a simple mobile reflectometer. Materials involved are standard commercial anodized sheet aluminium with layers of different thicknesses and standard high specular aluminium with a metaloxide layer system plus an anti-oxidation polymer coating. Results show that optical degradation is strongly dependent on climatic conditions. Non-organic coatings involved are primarily attacked by humid climates with higher amounts of atmospheric pollution. Standard anodized materials withstand outdoor and accelerated weathering. However reflectance tends to become less specular, which limits their application in concentrating technologies. Finally, small scale application tests have been performed to demonstrate the applicability concerning handling and mechanical connection with support structures. By measuring power density in the focus of a test collector, minimum specular reflectance requirements for trough systems can be defined.     

Optical Properties of Aluminum Oxide: Determined from Vacuum Ultraviolet and Electron Energy-Loss Spectroscopies

The optical properties of alpha-Al₂O₃ have been determined by two independent methods, vacuum ultraviolet (VUV) spectroscopy and electron energy-loss spectroscopy (EELS) over the energy range from 6 to 142 eV. For each experimental method two sets of high-quality data have been measured and analyzed from alpha-Al₂O₃. The evolution of the differences between the data for each experimental method and its associated analytical method indicate the reliability of the results, and the comparison between the methods emphasizes the relative advantages of each. VUV spectroscopy offers a higher energy resolution, resolving sharper features in the spectra, whereas EELS significantly extends the energy range, which has been exploited here to 140 eV but can be extended even further. Good overall consistency is found, but there are pronounced differences in the valence region from 10 to 30 eV, where strong absorptions are present, increasing the relative variability of the analysis. This demonstrates that accuracy estimates of the optical properties are meaningful only when supplied as a function of energy, because both strong intrinsic absorptions and weak experimental signals make accurate determinations difficult. Moreover, variations in the optical properties are observed most easily in the interband transition strength, J _cv, and are less evident when the optical properties are represented as the complex index of refraction. Because the optical properties can change with specimen origin and preparation and because of the details of data acquisition and numerical analysis procedures, assessing the contributions of each of these methods to our accurate knowledge of the optical constants is essential.     

美国食醋市场最新动态及发展趋势

目前全球每年调味品营业额高达2180亿美元，占到食品工业额的10%左右，是典型的“小产品、大市场”。据最新统计数字表明，美国食醋年消费量为130万kL，位居世界第一，其次为日本，年消费量为42万kL，德国居第三位。美国醋厂不仅规模大，而且厂家也多；我均食醋消费量为2.4L。