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991.
The oregano spice includes various plant species. The most common are the genus Origanum, native of Europe, and the Lippia, native of Mexico. Among the species of Origanum. their most important components are the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol. In the genus Lippia, the same compounds can be found. The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Some of the properties of this plant's extracts are being currently studied due to the growing interest for substituting synthetic additives commonly found in foods. Oregano has a good antioxidant capacity and also presents antimicrobial activity against pathogenic microorganisms like Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, among others. These are all characteristics of interest for the food industry because they may enhance the safety and stability of foods. There are also some reports regarding the antimutagenic and anticarcinogenic effect of oregano; representing an alternative for the potential treatment and/or prevention of certain chronic ailments, like cancer.  相似文献   
992.
Polyurethane foams with different formulations were synthesized and characterized for use as supporting matrices of granular solid adsorbents. The open cell content, specific gravity, thermal stability, and hydrophobicity were determined and related to the formulation composition. The synthesized foams had open cell contents of 88.1–98.5% and specific gravity values of 120–28 kg m?3. The thermal stability of the prepared foams was influenced mainly by the water content and the type of isocyanate used. The hydrophobicity was assessed by an analysis of the water adsorption isotherms determined on selected foams, and a correlation between these results and the formulation of the foams was attempted. Two types of activated carbons were supported in a polyurethane matrix. The adsorption characteristics evaluated before and after the supporting procedure, by nitrogen adsorption, revealed that there was only a moderate surface area reduction of 15–20%. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2045–2053, 2004  相似文献   
993.
Biocatalysis offers an alternative approach to conventional chemical processes for the production of single-isomer chiral drugs. Lipases are one of the most used enzymes in the synthesis of enantiomerically pure intermediates. The use of this type of enzyme is mainly due to the characteristics of their regio-, chemo- and enantioselectivity in the resolution process of racemates, without the use of cofactors. Moreover, this class of enzymes has generally excellent stability in the presence of organic solvents, facilitating the solubility of the organic substrate to be modified. Further improvements and new applications have been achieved in the syntheses of biologically active compounds catalyzed by lipases. This review critically reports and discusses examples from recent literature (2007 to mid-2015), concerning the synthesis of enantiomerically pure active pharmaceutical ingredients (APIs) and their intermediates in which the key step involves the action of a lipase.  相似文献   
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This paper presents a study on the curing conditions of several resin-impregnated papers and its impact on the performance of HPL (high-pressure decorative laminate). A new methodology for evaluating the bond strength development between the different layers of a HPL(overlay, decorative, and kraft papers) was developed using ABES (Automated Bonding Evaluation System) equipment. The proposed method can be applied to the study of the curing step of the different impregnated paper and the development of bonds between them (overlay paper on decorative paper, decorative paper on kraft paper, and kraft paper on kraft paper) trying to simulate the hot-pressing of an industrial HPL. This will permit to establish a more adapted temperature gradient in hot-press in order to achieve the same curing rate for all layers and provide a good final overall product quality.  相似文献   
997.
A new iron-based T 1 contrast agent consisting of a complex of iron ions coordinated to phosphate and amine ligands (Fe(phos) in short) has been characterized by spectroscopic and magnetic measurements. NMR relaxation studies showed r 1 values to be dependent on the phosphate salt concentration, K2HPO4, present in the medium. r 1 reaches a maximum value of 2.5 mM?1 s?1 for measurements carried out at 7 T and 298 K. 31P MRS, Mössbauer spectroscopy and magnetic measurements of Fe(phos) solutions suggest paramagnetic Fe3+ ions present in the studied iron–phosphate complex. In vitro and in vivo toxicity experiments with C6 cells and CD1 mice, respectively, demonstrated lack of toxicity for Fe(phos) at the highest dose tested in the MRI experiments (12 mM iron for C6 cells and 0.32 mmol iron/kg for mice). Finally, T 1 weighted images of brain tumours in mice have shown positive contrast enhancement of Fe(phos) for tumour afflicted regions in the brain.  相似文献   
998.
针对数据样本较少,且时间序列不连续的邯郸重度污染日的空气质量指标数据,采用基于数据分组的分数阶GM(1,1)模型(The data grouping GM(1,1) model with fractional order accumulation,简称DGFGM(1,1)),对邯郸地区2018—2019年12月28、29、30日三天的AQI及PM_(2. 5)、PM_(10)、NO_2的日均浓度进行预测。使用该模型预测的AQI、PM_(2. 5)、PM_(10)和NO_2的MAPE分别为2. 89%、3. 28%、3. 83%、3. 23%,表明DGFGM(1,1)模型具有良好的预测性能。预测结果显示,在当前的治理力度下,邯郸地区空气重污染的发生仍然难以避免,有些污染物浓度不降反升,除2018—2019年的12月30日的NO_2外,其他时间的所有污染物浓度全部超过标准限值,污染情况相当严重。当地有关部门应重视对极端重度污染天气的预防和治理,使得大气环境质量得以全面提升。  相似文献   
999.
简要分析了发电机组集散控制系统 (DCS)的CMOS电池对机组控制系统的重要性 ,介绍了目前MAXl0 0 0 PLUS集散控制系统的工作站、DBM、DPU的CMOS电池的使用观状及在的隐患 ,并针对性地提出了一些防范改进措施 ,以确保机组安全稳定运行  相似文献   
1000.
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