Glass fibers with clay nanocomposite coating: Improved barrier resistance in alkaline environment

Coatings made from neat vinyl ester and nanoclay reinforced vinyl ester composites are applied onto individual glass fibers as well as rovings to evaluate their barrier resistance against alkali and moisture attack. The fibers coated with clay nanocomposites present a significantly less damage caused by the diffusing alkali ions, giving rise to a much higher residual tensile strength after aging than the fibers without coating or those with a neat polymer coating. The static fatigue test performed on individual fibers verifies the advantage of using nanoclay composite to retard the corrosion process under the combined stress and alkaline environment. Similar beneficial effects of incorporating nanoclay on residual strength are identified for impregnated fiber bundles. The above observations confirm the excellent barrier characteristics of intercalated/exfoliated nanoclay in polymer that are applied in composite structures on both the microscopic and macroscopic scales.     

Dielectric loaded HTS resonators as frequency standards andlow-phase noise oscillators

High-quality, high-temperature superconducting (HTS) thin-films exhibit very low losses at microwave frequencies and, as a result, allow very high Q resonators to be produced. The size of such resonators may be significantly reduced by loading with low-loss single crystal dielectric. The potential for HTS dielectric loaded resonators as practical frequency standards and reference elements for low-phase-noise oscillators is assessed, with emphasis on operation at 60 K, a temperature readily attainable with compact Stirling cycle coolers     

Monoclonal Cell Line Generation and CRISPR/Cas9 Manipulation via Single‐Cell Electroporation

Stably transfected cell lines are widely used in drug discovery and biological research to produce recombinant proteins. Generation of these cell lines requires the isolation of multiple clones, using time‐consuming dilution methods, to evaluate the expression levels of the gene of interest. A new and efficient method is described for the generation of monoclonal cell lines, without the need for dilution cloning. In this new method, arrays of patterned cell colonies and single cell transfection are employed to deliver a plasmid coding for a reporter gene and conferring resistance to an antibiotic. Using a nanofountain probe electroporation system, probe positioning is achieved through a micromanipulator with sub‐micron resolution and resistance‐based feedback control. The array of patterned cell colonies allows for rapid selection of numerous stably transfected clonal cell lines located on the same culture well, conferring a significant advantage over slower and labor‐intensive traditional methods. In addition to plasmid integration, this methodology can be seamlessly combined with CRISPR/Cas9 gene editing, paving the way for advanced cell engineering.     

Application of synchronous fluorescence spectroscopy for the determination of some chemical parameters in PDO French blue cheeses

The present study was aimed at investigating the potential of using synchronous fluorescence spectroscopy (SFS) coupled with multivariate statistical analyses for the determination of some chemical parameters (pH, fat, dry matter, protein and soluble nitrogen) of French blue-veined cheeses belonging to four brands (FA-Fourme d’Ambert, FM-Fourme de Montbrison, BA-Bleu d’Auvergne and BC-Bleu des Causses). Three partial least square regression models with leave-one-out cross-validation technique were considered in the present study. The first one including the “Fourme cheeses” (FA and FM), the second one including the “Blue cheeses” (BA and BC) and the last one including the 4 Blue-veined cheeses (FA, FM, BA and BC). The models qualities were investigated principally by the R ² (coefficient of determination) and the RPD (ratio of standard deviation to root-mean-square error of cross-validation) factors. The results showed that SFS succeeded to predict ash and protein in Blue (ash: R ² = 0.90, RPD = 3.17; protein R ² = 0.80, RPD = 2.24) or Fourme cheeses (ash: R ² = 0.81, RPD = 2.29; protein R ² = 0.81, RPD = 2.26) when considered individually, while SFS failed to predict all the physicochemical parameters when the two groups were analyzed jointly.     

分光光度法测定维吾尔传统药用植物何首乌的总黄酮含量

以芦丁为对照品，用分光光度法测定何首乌提取物中总黄酮含量。得乙酸乙酯部位的黄酮含量最高，石油醚部位的黄酮含量最低。     

Comparison of electrothermal and hydride generation atomic absorption spectrometry for the determination of total arsenic in broiler chicken

The purpose of this study was to estimate total arsenic concentration in different tissues (leg, breast, liver and heart) of broiler chicken by hydride generation atomic absorption spectrometry (HGAAS) and graphite furnace atomic absorption spectrometry (GFAAS), prior to microwave assisted acid digestion. The accuracy of the techniques was evaluated by using certified reference material DORM-2. The percentage recoveries of total As were observed as 100.6% and 99.4% for HGAAS and GFAAS, respectively. The precision of the techniques, expressed as relative standard deviation, was observed as 1.71% and 4.18% for HGAAS and GFAAS measurements, respectively. The limits of detection for HGAAS and GFAAS were 0.025 μg/g and 0.052 μg/g, respectively. The concentrations of total arsenic in different tissues of broiler chicken were found in the range of 2.19–5.28, 2.15–5.22, 2.97–7.17 and 2.68–6.36 μg/g for leg, breast, liver and heart tissues, respectively. At a mean level of chicken consumption (60 g/person/day), people may ingest in the range of 72.0–85.1 μg arsenic/person/day from chicken alone.     

超声波提取紫草叶中总黄酮的工艺研究

对紫草叶中的总黄酮的含量和提取工艺进行了研究,通过单因素试验和正交试验确定超声提取最佳工艺是:以80%乙醇作为溶剂,料液比为1:30,在超声波功率为400W的条件下超声提取15min,其黄酮含量为5.58%。     

Volatile Compounds of Roasted and Steamed Malaysian Tropical Almond Nut (Terminalia catappa L.)

The flavor extract components contributing to the characteristic aroma notes of roasted and steamed tropical almond nuts were investigated by means of gas chromatography-olfactometry and mass spectrometry of solvent extracts. Roasting and steaming data revealed all of the main classes of compounds commonly listed as thermally generated flavors in oily seeds. A total of 72 volatile compounds were identified in the sample from roasted nuts; among these were 27 hydrocarbons, 12 aldehydes, 12 ketones, 8 acids, 4 esters, 3 alcohols, 3 furans, and a pyrazine. The steamed nuts, however, yielded 66 peaks from which 63 volatile compounds were identified (22 hydrocarbons, 9 aldehydes, 9 ketones, 9 esters, 4 acids, 9 alcohols, and a pyrazine). The small number of aldehydes, ketones, pyrazine, and alcohols identified are the ones most likely to contribute to the aroma of the nuts.     

Κ‐CN gene polymorphism in Nili‐ravi buffalo,Achai and Sahiwal cattle of Pakistan

Kappa‐casein (κ‐CN) is the subtype of casein protein, an important constituent of bovine milk protein. The current study was undertaken to investigate the genetic polymorphism in κ‐CN gene of Nili‐ravi buffalo, Achai and Sahiwal cattle of Pakistan using polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) technique. The Nili‐ravi buffalo was found to be monomorphic (genotype BB only) for κ‐CN gene. Achai cattle were polymorphic for κ‐CN (having three genotypes AA, AB and BB) with a frequency of 0.70, 0.18 and 0.12, respectively, while in Sahiwal cattle, both the genotypes AA and AB were found with genotypic frequencies of 0.92 and 0.08, respectively. The presence of genotype BB in Achai cattle is surprising as it is absent in most of the cattle breeds worldwide.