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The 3rd generation partnership project (3GPP) has defined the protocols and codecs for implementing media streaming services over packet-switched 3G mobile networks. The specification is based on IETF RFCs on audio/video transport. It also adds new features to achieve better adaptation to the mobile network environment. In this paper, we propose an algorithm for handover detection and fast buffer refill that is based on the existing feedback and signaling mechanisms. The proposed algorithm refills the receiver buffer at a faster pace during a limited time frame after a hard handover is detected in order to achieve higher video quality. 相似文献
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Abdul Wahab Syed Aleem Jan Abdur Rauf Zia ur Rehman Zahid Khan Aftab Ahmed Fatima Syed Sher Zaman Safi Hamayun Khan Muhammad Imran 《Journal of Zhejiang University. Science. B》2018,19(2):120-129
Objective
Scandix pecten-veneris L. is a less studied wild edible herb and is considered an extinct plant species in many parts of the world. This study was designed to evaluate its phytochemical composition and biological potential of S. pecten-veneris L.Methods
Phytochemicals including alkaloids, flavonoids, polyphenols, and tannins were determined in extracts of S. pecten-veneris. Antioxidant activity was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), while reducing power was tested by ferric reducing/antioxidant power (FRAP) assay. Antimicrobial activity against seven bacterial and four fungal strains was evaluated using agar well diffusion assay. Enzymes inhibition study was performed for urease, phosphodiesterase-I, and catalase-II.Results
S. pecten-veneris showed moderate antiradical activity and reducing potential of hydroxyl radicals to about 20% of the initial value. The antioxidant activity of various extracts of S. pecten-veneris showed a linear correlation with total phenolic contents in the order of water>n-butanol>chloroform>ethyl acetate>methanol extracts. S. pecten-veneris leaves showed the highest inhibitory activity against Staphylococcus aureus while the highest antifungal activity was observed against Candida albicans. The plant extract was most potent against urease enzymes but showed moderate activity against phosphodiestrase-I and carbonic anhydrase-II.Conclusions
Our data demonstrate that in addition to its culinary uses, S. pecten-veneris has good medicinal potential and hence could be used for treating some specific health ailments.4.
Abdul WAHAB Syed Aleem JAN Abdur RAUF Zia ur REHMAN Zahid KHAN Aftab AHMED Fatima SYED Sher Zaman SAFI Hamayun KHAN Muhammad IMRAN 《Journal of Zhejiang University. Science. B》2018,(2)
目的:本研究旨在测定Scandix pecten-veneris L.的植物素和评价其生物学潜力。方法:测定S.pecten-veneris提取物中植物素的含量,包括生物碱、黄酮、多酚和单宁。使用2,2-二苯基-1-苦肼基(DPPH)测定抗氧化活性;同时通过铁还原/抗氧化能力(FRAP)测定还原能力;使用琼脂扩散测定法评价对七种细菌和四种真菌菌株的抗微生物活性。同时,对脲酶、磷酸二酯酶-Ⅰ和过氧化氢酶-Ⅱ进行酶抑制研究。结论:沙门氏菌显示出适度的抗自由基活性;羟基自由基的潜能降至初始值的20%左右。S.pectenveneris多种提取物的抗氧化活性与总酚含量呈线性相关。S.pecten-veneris叶对金黄色葡萄球菌表现出最高的抑制活性;对白色念珠菌表现出到最高的抗真菌活性。植物提取物对脲酶的活性最有效;对磷酸二酯酶-Ⅰ和碳酸酐酶-Ⅱ显示出中等活性。结果表明,S.pecten-veneris具有良好的药用潜力,可用于治疗一些特定的疾病。 相似文献
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