铜蒸气激光器窗口污染实验研究

提出铜蒸气激光器窗口污染主要是由放电管中钻电极的溅射以及金属钢原子的热扩散引起。对１０Ｗ的国产器件，当连续运转１００ｋｗｈ后，窗口透过率由８０％下降至６５％左右，同时用化学方法测得吸附于器件富片内表面沾污层中钻铜含量比为３：１。另外，还讨论了窗口沾污对器件输出功率等因素的影响。最后，实验采用加长器件阳极端部管长的方式减少沾污，并得到了实际应用。     

既有混凝土弹性模量的证据理论估计方法

提出了一种估计既有混凝土的弹性模量的新方法．该方法基于证据理论，可充分利用已有资料所提供的信息，能更好地反映混凝土的实际情况。     

电子枪发射系统对上屏束点的影响

利用ＳＥＵ－８７５３Ｄ程序对彩色显像管电子枪系统做了详细地计算，得到了放大率，球差，空间电荷效应的变化曲线，由此看出它们对上屏束点大小的影响，并且由这些曲线中找到使上屏束点最小的结构。     

时序电路的自锁与自解锁

本文讨论了在不考虑冗余状态设计时序电路时，可能会导致“自锁”现象，并提出了设计自解锁功能异步时序电路应当遵循的一种规范化方法。     

TrueType字体文件格式初探

随着Ｗｉｎｄｏｗｓ３．ｘ的流行及其后续版本对ＴｒｕｅＴｙｐｅ字体的支持，ＴＴＦ的重要性已越来越受到人们的关注。ＴＴＦ不仅可以用来描述西文字体，也可以用来描述汉字字形。本文比较详细地分析了ＴＴＦ文件的结构，描述了其中的重要表格，为进一步研究了ＴＴＦ提供了基本知识。     

Molecular diagnosis of 5α-reductase type II deficiency in Brazilian siblings with 46,XY disorder of sex development

The steroid 5α-reductase type II enzyme catalyzes the conversion of testosterone (T) to dihydrotestosterone (DHT), and its deficiency leads to undervirilization in 46,XY individuals, due to an impairment of this conversion in genital tissues. Molecular analysis in the steroid 5α-reductase type II gene (SRD5A2) was performed in two 46,XY female siblings. SRD5A2 gene sequencing revealed that the patients were homozygous for p.Gln126Arg missense mutation, which results from the CGA > CAA nucleotide substitution. The molecular result confirmed clinical diagnosis of 46,XY disorder of sex development (DSD) for the older sister and directed the investigation to other family members. Studies on SRD5A2 protein structure showed severe changes at NADPH binding region indicating that structural modeling analysis can be useful to evaluate the deleterious role of a mutation as causing 5α-reductase type II enzyme deficiency.     

Metabolic responses to high glycemic index and low glycemic index meals: a controlled crossover clinical trial

Background  

The consumption of low glycemic index (LGI) foods before exercise results in slower and more stable glycemic increases. Besides maintaining an adequate supply of energy during exercise, this response may favor an increase in fat oxidation in the postprandial period before the exercise compared to high glycemic index (HGI) foods. The majority of the studies that evaluated the effect of foods differing in glycemic index on substrate oxidation during the postprandial period before the exercise are acute studies in which a single meal is consumed right before the exercise. The purpose of this study was to investigate the effect of consuming two daily HGI or LGI meals for five consecutive days on substrate oxidation before the exercise and in the concentrations of glucose, insulin and free fatty acids before and during a high intensity exercise.     

Development and scale-up of thermoplastic poly(ether-ester) glycol polyurethanes for flexography

This study presents an experimental essay on the production of thermoplastic polyurethanes for flexographic printing ink applications. Four formulations were obtained by step-growth polymerization reactions having the pre-polymer 4,4′-diphenylmethylene diisocyanate and Voranol 2120 L® catalyzed by dibutyltin dilaurate as common ground. In the chain extension step, ethanol or ethyl acetate was used as solvent, and the use or not of castor oil as a chain extender in addition to hexanedioic acid and 2,2′-oxydi(ethan-1-ol) was evaluated. The chemical structures of the synthesized thermoplastic polyurethanes (TPUs) were evaluated by Fourier transform infrared spectroscopy, ¹H NMR, gel permeation chromatography, differential scanning calorimetry, and rheological features were assessed by density and viscosity analysis. The TPU resins were used to produce flexographic printing inks and further tested by friction, adhesion, gloss, and Gardner viscosity essays. It was found that the castor oil presence enhanced ink viscosity in 66% (from 26,790 to 44,440 Pa s) as well as improved strength. Formulations using ethanol as solvent showed the best results. The experiments were carried in a 250 ml reactor and then, scaled up to 2000 ml, keeping the power transfer per unit of volume constant at around 0.8 W/L. The analytical results from the larger scale were as good as the obtained in scale one, showing promising application.     

Interlaboratory comparison of sulfur mass fraction in gasoline: MWDXRF spectrometry versus UV fluorescence

The authors’ aims are to compare the performance of two test methods and participants’ results with combined results from a group in the same round and limits determined by the variability of participant results. Moreover, this study can be considered as a tutorial; because stability, homogeneity and characterization tests related to interlaboratory comparisons are detailed. Sulfur mass fractions in three different samples of gasoline (with 26% anhydrous ethanol) are analyzed by ultraviolet fluorescence or monochromatic wavelength dispersive X-ray fluorescence spectrometry, by the participating laboratories. Applying robust statistical methods, the results show that there are systematic errors between both test methods.