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71.
72.
光弹性法是确定应力集中系数的有效手段,在实际工程中应力参数都是通过分析光弹干涉条纹图获得的,由于光弹干涉条纹图的复杂性,且影响成像质量的因素较多,因此如何从光弹干涉条纹图中撇开其复杂性,较高精度的提取骨架线,是一项较困难的工作,本文提出一种由改进的Canny算子对条纹方位图进行直接运算提取光弹条纹骨架线的算法,实验表明此方法对光弹条纹图很有效。 相似文献
73.
The antibacterial activity of essential oil and methanolic extract of Teucrium polium was determined against Pseudomonas aeruginosa, Pantoea agglomerans, Brenneria nigrifluens, Rhizobium radiobacter, Rhizobium vitis, Streptomyces scabies, Ralstonia solanacearum, Xanthomonas campestris and Pectobacterium cartovorum by disc diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration were determined by using the serial dilution method. Chemical composition of essential oil and methanolic extract was determined by GC-MS and HPLC. α-Pinene (25.769%) and myrcene (12.507) were of the highest percentage in T. polium essential oil, and sinapic acid (15.553 mg/g) and eugenol (6.805 mg/g) were the major compounds in the methanolic extract. Our results indicate that both methanolic extract and essential oil did not show antibacterial activity against P. aeruginosa. Also the essential oil did not show antibacterial activity against P. cartovorum. In general, both methanolic extract and essential oil showed the same antibacterial activity against R. solanacearum, P. agglomerans, B. nigrifluens and S. scabies. 相似文献
74.
T.V.A. Lordani M.A. Brenzan L.E.R. Cortez C.R.F. Lordani P.A. Honda M.V.C. Lonardoni 《Natural product research》2015,29(10):953-957
This study evaluated the wound healing effects of topical application of an emulsion containing the HPLC-standardised extract from Calophyllum brasiliense Cambess (Clusiaceae) leaves in rats. The macroscopic analysis demonstrated that the wounds treated with the C. brasiliense emulsion healed earlier than the wounds treated with emulsion base and Dersani®. The percentage of wound healing in the group treated with the C. brasiliense emulsion was significantly higher than in the other groups at 7 and 14 days. On day 14, the animals treated with the C. brasiliense emulsion exhibited a 90.67% reduction of the wound areas. The histological evaluation revealed that on day 21, the group treated with the C. brasiliense emulsion exhibited a significant increase in fibroblasts compared with the other groups. Thus, the C. brasiliense emulsion had healing properties in the topical treatment of wounds and accelerated the healing process. 相似文献
75.
A simple and rapid method was established and validated for the simultaneous quantification of 10 saponins, namely ginsenosides-Rb1, Rb2, Rb3, Rc, Rd, Rg1, Rg2, Re, Rf and Notoginsenside R1, in Chinese Shizhu Panax by ultra performance liquid chromatography coupled with an electrospray mass spectrometry (UPLC-ESI-MS). In addition, the contents of the analytes in different parts of Chinese Shizhu Panax were also analysed. The results showed that the concentration of saponins had a reference to the different parts of Chinese Shizhu Panax. The established method could be used as a new analytical approach for assessment of the quantity of Chinese Shizhu Panax. 相似文献
76.
Murad Ali Khan 《Natural product research》2015,29(24):2318-2321
This study describes the in vitro inhibition of protein denaturation of extract/fractions of Withania somnifera and isolated withanolides including 20β hydroxy-1-oxo(22R)-witha-2,5,24 trienolide (1), (20R,22R-14α,20α)-dihydroxy-1-oxowitha-2,5,16,24 tetraenolide (2). The results showed that the extract/fractions of the plant evoked profound inhibitory effect on thermal-induced protein denaturation. The chloroform fraction caused the most dominant attenuation of 68% at 500 μg/mL. The bioactivity-guided isolation from chloroform fraction led to the isolation of compounds 1 and 2 that showed profound protein inhibition with 78.05% and 80.43% effect at 500 μg/mL and thus strongly complimented the activity of extract/fractions. In conclusion, extract/fractions of W. somnifera possessed strong inhibition of protein denaturation that can be attributed to these isolated withanolides. 相似文献
77.
Development of a method to screen and isolate potential α‐glucosidase inhibitors from Panax japonicus C.A. Meyer by ultrafiltration,liquid chromatography,and counter‐current chromatography
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A new assay based on ultrafiltration, liquid chromatography and mass spectrometry was developed for the rapid screening and identification of the ligands for α‐glucosidase from the extract of Panax japonicus. Six saponins were identified as α‐glucosidase inhibitors. Subsequently, the specific binding ligands, namely, notoginsenoside R1, ginsenoside Rb1, chikusetsusaponin V, chikusetsusaponin IV, chikusetsusaponin IVa, and ginsenoside Rd (the purities were 94.18, 95.43, 96.09, 93.26, 94.50, 93.86%, respectively) were separated by counter‐current chromatography using two‐phase solvent systems composed of tert‐butyl methyl ether, acetonitrile, 0.1% aqueous formic acid (3.8:1.0:4.4, v/v/v) and the solvent system composed of methylene chloride, isopropanol, methanol, 0.1% aqueous formic acid (5.8:1.0:6.0:2.2, v/v/v). The results demonstrate that ultrafiltration, liquid chromatography and mass spectrometry combined with high‐speed counter‐current chromatography might provide not only a powerful tool for screening and isolating α‐glucosidase inhibitors in complex samples but also a useful platform for discovering bioactive compounds for the prevention and treatment of diabetes mellitus. 相似文献
78.
《Journal of separation science》2017,40(7):1500-1507
The increasing world population with their growing consumption of goods escalates the issue of sustainability concepts with increasing demands in recycling technologies. Recovery of post‐consumer packaging waste is a major topic in this respect. However, contamination with odorous constituents currently curtails the production of recycling products that meet the high expectations of both consumers and industry. To guarantee odor‐free recyclates, the main prerequisite is to characterize the molecular composition of the causative odorants in post‐consumer plastic packaging waste. However, targeted characterization of odorous trace contaminants among an abundance of volatiles is a major challenge and requires specialized and high‐resolution analytical approaches. For this aim, post‐consumer packaging waste was characterized by sensory analysis and two‐dimensional high resolution gas chromatography coupled with mass spectrometry and olfactometry. The 33 identified odorants represent various structural classes as well as a great diversity of smell impressions with some of the compounds being identified in plastics for the first time. Substances unraveled within this study provide insights into sources of odorous contamination that will require specific attention in the future in terms of screening and prevention in recycling products. 相似文献
79.
Shah Hussain Cornelia Pezzei Yüksel Güzel Matthias Rainer Christian W. Huck Günther K. Bonn 《Analytica chimica acta》2014
An efficient blood plasma clean-up method was developed, where methanol protein precipitation was applied, followed by zirconium silicate assisted exclusion of residual proteins. A strong binding of zirconium (IV) silicate to the proteins enabled the elimination of remaining proteins after solvent deproteinization through a rapid solid-phase extraction (SPE) procedure. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF MS) was used for monitoring the proteins during clean-up practice applied to human plasma samples. The proteins were quantified by colorimetric detection using the bicinchoninic acid (BCA) assay. The presented analytical strategy resulted in the depletion of >99.6% proteins from human plasma samples. Furthermore, high-performance liquid chromatography hyphenated to diode-array and electrospray ionization mass spectrometric detection (HPLC–DAD/ESI MS) was applied for qualitative and quantitative analysis of the caffeoylquinic acids (CQAs) and their metabolites in human plasma. The procedure demonstrated high recoveries for the standard compounds spiked at different concentrations. Cynarin and chlorogenic acid were recovered in the range of 81–86% and 78–83%, respectively. Caffeic acid was extracted in the excess of 89–92%, while ferulic acid and dihydroxyhydrocinnamic acid showed a recovery of 87–91% and 92–95%, respectively. The method was partially validated in accordance with FDA-Industry Guidelines for Bioanalytical Method Validation (2001). The presented scheme improves the clean-up efficacy of the methanol deproteinization, significantly reduces the matrix effects and provides a great analytical tool for the isolation of small molecules from human plasma. 相似文献
80.