Identification of Dancer Emulsion

There is some doubt concerning the identity of the emulsion vehicle used in J. B. Dancer’s microphotographs. Separation and analytical identification revealed that in two specimens the binder was collodion.     

Numerical analysis for the prediction of bump prone conditions:A southern Appalachian pillar coal bump case study

Two miners were fatally injured when a pillar bump occurred during retreat mining in a southern West Virginia coal mine. The mine was operating in the Eagle seam with overmining in the No. 2 Gas and Powellton seams. A coal bump is defined as a sudden and violent failure of coal caused by the release of stored strain energy in the pillar. While significant strides have been made by academia, industry,and regulatory agencies to better understand bump conditions and mitigation techniques, coal bumps represent a long standing, highly site-specific engineering problem in which the exact failure mechanism is not clearly understood. In this case history, a cut-by-cut analysis of retreat mining operations was conducted on the 4 East Main leading up to the pillar bump event. Numerical input parameters were derived from site-specific geologic information and mine geometry for the analysis of pillar stress conditions and energy release using LaModel. An overview of stress conditions in the panel was presented including a precursor event that occurred two crosscuts inby the bump site. The methodology presented in the paper for the evaluation of the fatal bump event can be used for the identification of bump prone conditions prior to development and retreat of a mining area.     

开关电容ADC及其驱动放大器之间的阻抗谐振匹配方法

高采样速率模数转换器（ADC）通常用在现代无线接收器设计中,以中频（IF）采样速率采集复数调制的信号.这类设计通常都选用基于CMOS开关电容的ADC,因为它们的低成本和低功耗特点很吸引人。但这类ADC采用一种直接连接到采样网络的无缓冲器的前端,这样就会出现驱动ADC的放大器的输入跟踪和保持阻抗随时间变化的问题.为了有效地驱动ADC,使噪声最低和有用信号失真最小,必须设计一种无源网络接口帮助抑制宽带噪声,并对跟踪阻抗和保持阻抗进行变换以便为驱动放大器提供更好的负载阻抗。针对几种常见的IF频率,本文中提出了一种谐振匹配方法,用于将跟踪和保持阻抗转换为比较容易计算的负载,从而实现抗锯齿滤波器的精密设计。     

Cross-Omics Analysis of Fenugreek Supplementation Reveals Beneficial Effects Are Caused by Gut Microbiome Changes Not Mammalian Host Physiology

Herbal remedies are increasing in popularity as treatments for metabolic conditions such as obesity and Type 2 Diabetes. One potential therapeutic option is fenugreek seeds (Trigonella foenum-graecum), which have been used for treating high cholesterol and Type 2 diabetes. A proposed mechanism for these benefits is through alterations in the microbiome, which impact mammalian host metabolic function. This study used untargeted metabolomics to investigate the fenugreek-induced alterations in the intestinal, liver, and serum profiles of mice fed either a 60% high-fat or low-fat control diet each with or without fenugreek supplementation (2% w/w) for 14 weeks. Metagenomic analyses of intestinal contents found significant alterations in the relative composition of the gut microbiome resulting from fenugreek supplementation. Specifically, Verrucomicrobia, a phylum containing beneficial bacteria which are correlated with health benefits, increased in relative abundance with fenugreek. Metabolomics partial least squares discriminant analysis revealed substantial fenugreek-induced changes in the large intestines. However, it was observed that while the magnitude of changes was less, significant modifications were present in the liver tissues resulting from fenugreek supplementation. Further analyses revealed metabolic processes affected by fenugreek and showed broad ranging impacts in multiple pathways, including carnitine biosynthesis, cholesterol and bile acid metabolism, and arginine biosynthesis. These pathways may play important roles in the beneficial effects of fenugreek.     

Methylmercury formation in a wetland mesocosm amended with sulfate

This study used an experimental model to evaluate methylmercury accumulation when the soil of a constructed wetland is amended with sulfate. The model was planted with Schoenoplectus californicus and designed to reduce wastestream metals and metal-related toxicity. The soil was varied during construction to provide a control and two sulfate treatments which were equally efficient at overall mercury and copper removal. After an initial stabilization period, methylmercury concentrations in porewater were up to three times higher in the sulfate-treated porewater (0.5-1.6 ng/L) than in the control (<0.02-0.5 ng/L). Mean percent methylmercury was 9.0% in the control with 18.5 and 16.6% in the low- and high-sulfate treatments, respectively. Methylmercury concentrations measured in mesocosm surface water did not reflect the differences between the control and the sulfate treatments that were noted in porewater. The mean bulk sediment methylmercury concentration in the top 6 cm of the low-sulfate treatment (2.33 ng/g) was significantly higher than other treatment means which ranged from 0.96 to 1.57 ng/g. Total mercury in sediment ranged from 20.8 to 33.4 ng/g, with no differences between treatments. Results suggest that the non-sulfate-amended control was equally effective in removing metals while keeping mercury methylation low.     

Mica composites of improved strength

Mineral fillers of flake configuration such as mica can, in principle, produce large increases in modulus and strength especially if the flake is oriented predominantly in a plane. Additionally, the resulting composites have the advantage of possessing isotropic properties in the plane of orientation, thereby minimizing the warpage normally associated with the injection molding of fiber-reinforced thermoplastics. However, to properly transmit stress from the matrix to the mica and minimize the effect of defects in morphology, a ductile matrix is required with adequate interaction or adhesion between phases. Many of the above conclusions are documented in the literature and are confirmed by our investigations of the system mica-polypropylene. The novelty of this effort rests upon (1) successful attempts to identify specific non-silane additives which by co-blending suitably modify the mica-polypropylene interface, (2) to demonstrate the remarkable effects of time-temperature during melt processing on the behavior of this system; and, (3) to show the relation between composition and time-temperature effects on resultant mechanical, physical, and thermal properties. Most notably, large improvements in tensile and flexural strength and heat distortion temperature can be attributed to the use of small amounts of chlorinated organic compounds blended under carefully selected melt process conditions. Some speculation concerning the mechanism of interaction will be discussed and the resultant potential for increased application will also be outlined.     

The use of video image analysis for quantitative measurement of visible fat and lean in meat: Part 4- application of image analysis measurement techniques to minced meats

The quantitative measurement of fat in minced meat by video techniques has, to date, been impractical due to the nature of the raw material and camera limitations in particle resolution. The latter have been enhanced by improving the optical system and by illuminating the meat with a limited wavelength ultraviolet light source. Problems with fat smear and drip stain, causing over- and under-estimation of fat, respectively, have been overcome by better control of mincing conditions. Tempering of the meat to between -2°C and -5°C before mincing gave the best results. The level of fat detection was unchanged for up to 20 min after mincing, but, by 2 h, the initial value had fallen by 50%. Magnifying the field of view, thus reducing the sample size measured by 50%, did not adversely affect results with 4mm-10mm diameter mince. The system could not accurately resolve mince below 4 mm. Estimation of total lipid from video data using prediction equations was in good agreement with chemical analysis (r=0·99 for 10mm mince, r=0·95 for 4 mm mince). Video image analysis (VIA) can now be effectively extended to areas of meat processing using particulate meats.     

Light aromatics from the hydropyrolysis of coal

The hydropyrolysis of British coals was studied at hydrogen pressures of 5–15 MPa using heating rates of up to 30 K s^?1. In a single-stage reactor, hydropyrolysis of a high-volatile coal gave a maximum yield of 4.5 Wt % of single-ring aromatics. The results suggested that the evolution of volatiles and their cracking to benzene, toluene and xylenes were sequential reactions. This was confirmed using a two-stage reactor in which the coal was heated in one zone and the volatiles cracked in a separate, isothermally heated zone. Yields of up to 12 wt % benzene were then obtained from a high-volatile bituminous coal in hydrogen at 15 MPa, both the cracking temperature and the vapour residence time being separately optimized. Hydropyrolysis of model compounds showed that benzene was a major product of the cracking of polynuclear aromatics under hydrogen pressure.