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排序方式: 共有639条查询结果,搜索用时 15 毫秒
21.
The U.S. Food Safety and Inspection Service (FSIS) pathogen reduction-hazard analysis critical control point systems final rule, published in 1996, established Salmonella performance standards for broiler chicken, cow and bull, market hog, and steer and heifer carcasses and for ground beef, chicken, and turkey meat. In 1998, the FSIS began testing to verify that establishments are meeting performance standards. Samples are collected in sets in which the number of samples is defined but varies according to product class. A sample set fails when the number of positive Salmonella samples exceeds the maximum number of positive samples allowed under the performance standard. Salmonella sample sets collected at 1,584 establishments from 1998 through 2003 were examined to identify factors associated with failure of one or more sets. Overall, 1,282 (80.9%) of establishments never had failed sets. In establishments that did experience set failure(s), generally the failed sets were collected early in the establishment testing history, with the exception of broiler establishments where failure(s) occurred both early and late in the course of testing. Small establishments were more likely to have experienced a set failure than were large or very small establishments, and broiler establishments were more likely to have failed than were ground beef, market hog, or steer-heifer establishments. Agency response to failed Salmonella sample sets in the form of in-depth verification reviews and related establishment-initiated corrective actions have likely contributed to declines in the number of establishments that failed sets. A focus on food safety measures in small establishments and broiler processing establishments should further reduce the number of sample sets that fail to meet the Salmonella performance standard. 相似文献
22.
Tatiana B. Eronina Valeriya V. Mikhaylova Natalia A. Chebotareva Kristina V. Tugaeva Boris I. Kurganov 《International journal of molecular sciences》2022,23(7)
Protein–protein interactions (PPIs) play an important role in many biological processes in a living cell. Among them chaperone–client interactions are the most important. In this work PPIs of αB-crystallin and glycogen phosphorylase b (Phb) in the presence of betaine (Bet) and arginine (Arg) at 48 °C and ionic strength of 0.15 M were studied using methods of dynamic light scattering, differential scanning calorimetry, and analytical ultracentrifugation. It was shown that Bet enhanced, while Arg reduced both the stability of αB-crystallin and its adsorption capacity (AC0) to the target protein at the stage of aggregate growth. Thus, the anti-aggregation activity of αB-crystallin increased in the presence of Bet and decreased under the influence of Arg, which resulted in inhibition or acceleration of Phb aggregation, respectively. Our data show that chemical chaperones can influence the tertiary and quaternary structure of both the target protein and the protein chaperone. The presence of the substrate protein also affects the quaternary structure of αB-crystallin, causing its disassembly. This is inextricably linked to the anti-aggregation activity of αB-crystallin, which in turn affects its PPI with the target protein. Thus, our studies contribute to understanding the mechanism of interaction between chaperones and proteins. 相似文献
23.
24.
Nader Makki Kristina W. Thiel Francis J. Miller Jr. 《International journal of molecular sciences》2013,14(10):20597-20613
The epidermal growth factor receptor (EGFR) family and its ligands serve as a switchboard for the regulation of multiple cellular processes. While it is clear that EGFR activity is essential for normal cardiac development, its function in the vasculature and its role in cardiovascular disease are only beginning to be elucidated. In the blood vessel, endothelial cells and smooth muscle cells are both a source and a target of EGF-like ligands. Activation of EGFR has been implicated in blood pressure regulation, endothelial dysfunction, neointimal hyperplasia, atherogenesis, and cardiac remodeling. Furthermore, increased circulating EGF-like ligands may mediate accelerated vascular disease associated with chronic inflammation. Although EGFR inhibitors are currently being used clinically for the treatment of cancer, additional studies are necessary to determine whether abrogation of EGFR signaling is a potential strategy for the treatment of cardiovascular disease. 相似文献
25.
Linden (Tilia cordata) bark was shown to contain an antifeedant effective against the large pine weevil, Hylobius abietis. Soxhlet extraction of inner and outer bark resulted in an extract that showed antifeedant activity in a microfeeding assay. The extract was fractionated by chromatography on silica gel using gradient elution with solvents of increasing polarity. The content of the fractions obtained was monitored by thin layer- and gas chromatography. Fractions of similar chemical composition were merged. Two of the 17 fractions showed antifeedant activity in the microfeeding assay. Nonanoic acid was identified in both of these fractions. Subsequent testing in the microfeeding assay showed that nonanoic acid possessed strong antifeedant activity against H. abietis adults. 相似文献
26.
Xu Xuan Khoshima Sina Karajic Milana Balderman Jan Markovic Katarina Scancar Janez Samardzija Zoran Sturm Saso Rozman Kristina Zuzek 《Journal of Applied Electrochemistry》2022,52(7):1081-1090
Journal of Applied Electrochemistry - The consumption of critical raw materials, especially those in permanent magnets of Nd–Fe–B and Sm–Co-type, has significantly grown in the... 相似文献
27.
Kristina Hoffmann Tatjana Friedrich Bernd Tieke 《Polymer Engineering and Science》2011,51(8):1497-1506
Polyelectrolyte blend films and membranes were prepared upon alternating electrostatic adsorption of polyallylamine hydrochloride (PAH) and mixtures of polystyrene sulfonate (PSS) and polyacrylic acid (PAA) in different ratio on solid supports. Infrared studies indicated that the PSS‐PAA blend composition of the films always differed from the mixture composition in the dipping solution, PSS being preferentially adsorbed. Films deposited on porous supporting membranes (polyacrylonitrile/polyethylene terephthalate) were studied on their ion permeation under diffusion dialysis conditions, and their flux and salt rejection under nanofiltration and reverse osmosis (RO) conditions. Blend membranes prepared at pH 1.7 exhibit a significantly improved anion separation and salt rejection, the ideal separation factor α(NaCl/Na2SO4) of a membrane prepared from a PSS:PAA mixture of 1:1 (w/w) being 197 ± 10 (pure PAH/PSS: 45). The NaCl and Na2SO4 rejections under RO conditions are 85 and 97% (pure PAH/PSS: 15 and 27%), respectively. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers 相似文献
28.
Dr. Kristina Goncharenko Dr. Michele Mari Dr. Yves P. Auberson Brieuc Matagne 《ChemMedChem》2020,15(24):2359-2362
The European Federation for Medicinal Chemistry (EFMC) created the Young Scientists Network (YSN) to support early-career medicinal chemists and chemical biologists. By doing this, it addressed the rapid changes taking place in the scientific community and in our society, such as the rise of social media, the evolution of the gender balance in the scientific population, and educational needs. Creating the YSN was also a way to ensure that the next generation of scientists would contribute to shaping EFMC's strategy, while recognizing and addressing their needs. The YSN was set up as a very dynamic concept, and has now developed to the point where its impact is evident. The activities it promotes complement EFMC's community support and scientific opportunities, rejuvenating the Federation and preparing it for the future. It also provides opportunities for many brilliant young scientists, who do not hesitate to invest time and energy in supporting our community and shaping their own future. 相似文献
29.
Production and Emulsifying Effect of Polyglycerol and Fatty Acid Esters with Varying Degrees of Esterification 下载免费PDF全文
Khidmet S. Shikhaliev Nadezhda V. Stolpovskaya Mikhail Yu. Krysin Anna V. Zorina Denis V. Lyapun Fedor I. Zubkov Kristina Yu. Yankina 《Journal of the American Oil Chemists' Society》2016,93(10):1429-1440
Esters with acyl groups can be formed by the esterification of polyglycerol. The purpose of the present study was to produce fatty acid esters [hexanoic (caproic), octanoic (caprylic), decanoic (capric), dodecanoic (lauric), tetradecanoic (myristic), hexadecanoic (palmitic), octadecanoic (stearic)] and polyglycerol (average number‐of degrees of polymerization of 5) with varying degrees of esterification and to examine their emulsifying properties. A number of fundamental catalysts of polyglycerol acylation reactions by methyl esters of carboxylic acid were studied, and sodium methoxide was found to be the best choice. The temperature rate of transesterification increased from 180 to 220 °C with the fatty acid chain alkyl residue. Synthesized mono‐, di‐, tri‐, tetra‐, and heptaesters of various fatty acids and polyglycerol provided the highest hydroxyl values from 15 to 815 mg KOH g?1 and saponification values from 82 to 321 mg KOH g?1. The emulsifying properties were assessed for all polyglycerol and fatty acid esters, with results showing maximum emulsifying effect for tri‐ and tetraesters of capric, lauric, and caprylic acids. Regardless of the hydrophilic–lipophilic balance value (HLB) of polyglycerol esters and carboxylic acid, a 4:1 ratio of sunflower oil to water formed a water‐in‐oil type emulsion. When mixing oil and water in a 1:1 ratio, mono‐ and diesters of polyglycerol formed an oil‐in‐water type emulsion, heptaesters formed a water‐in‐oil type emulsion, and tri‐ and tetraesters formed both of types of emulsions, depending on the length of the acid hydrocarbon radicals. 相似文献
30.
Dr. Andrea C. Kneuttinger Martin Winter Nadja A. Simeth Kristina Heyn Prof. Dr. Rainer Merkl Prof. Dr. Burkhard König Prof. Dr. Reinhard Sterner 《Chembiochem : a European journal of chemical biology》2018,19(16):1750-1757
The artificial regulation of proteins by light is an emerging subdiscipline of synthetic biology. Here, we used this concept to photocontrol both catalysis and allostery within the heterodimeric enzyme complex imidazole glycerol phosphate synthase (ImGP‐S). ImGP‐S consists of the cyclase subunit HisF and the glutaminase subunit HisH, which is allosterically stimulated by substrate binding to HisF. We show that a light‐sensitive diarylethene (1,2‐dithienylethene, DTE)‐based competitive inhibitor in its ring‐open state binds with low micromolar affinity to the cyclase subunit and displaces its substrate from the active site. As a consequence, catalysis by HisF and allosteric stimulation of HisH are impaired. Following UV‐light irradiation, the DTE ligand adopts its ring‐closed state and loses affinity for HisF, restoring activity and allostery. Our approach allows for the switching of ImGP‐S activity and allostery during catalysis and appears to be generally applicable for the light regulation of other multienzyme complexes. 相似文献