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21.
S. Afaque M. M. Siddiqui I. Ahmad M. S. Siddiqui S. M. Osman 《European Journal of Lipid Science and Technology》1987,89(11):433-435
Vernolic acid represents 22.3% of the constituent fatty acids of the speed oil of an additional hitherto unexamined species of Bignoniaceae Kigelia pinnata. Its identification is based on comparative informations from thin-layer chromatography, infrared analysis, gas liquid chromatography and nuclear magnetic resonance spectroscopy with that of reference sample of Vernonia anthelmintica seed oil. The other fatty acids in this oil are: 14:0 (0.4), 16:0 (25.4), 18:0(0.9), 18:1 (8.9) and 18:2 (42.0%). K. pinnata is the first species of Bignoniaceae to be reported to contain vernolic acid in moderate amount. 相似文献
22.
Mercier Gustavo A. Jr; Osman Roman; Weinstein Harel 《Protein engineering, design & selection : PEDS》1988,2(4):261-270
A proton transfer triggered by a ligand interacting with thereceptor had been suggested as the initial step in the activationof a receptor for the neurotransmitter serotonin (5-hydroxy-tryptamine;5-HT). To evaluate the role of the receptor macromolecule inmodulating the primary molecular event in ligand-mediated activation,the process of proton transfer was analysed in the environmentof a protein model for the 5-HT receptor. In the absence ofa detailed receptor structure, the enzyme actinidin was chosenas the model for the receptor based on criteria obtained fromstructure-activity considerations on the ligands. The firstsimulation of a mechanism for receptor activation was performedon this model using methods of theoretical chemistry to studythe effect of specific structural elements. The premise is thatthe role of the elements of secondary structure of soluble proteins(e.g. actinidin) in determining structure-function relationsin these macromolecules is maintained when these elements arepart of membrane-bound receptor proteins. Results from the calculationsof the effects of the six alpha helices of actinidin on theproton transfer process from the imidazolium side chain of His162 to the thiol side chain of Cys 25 in the protein show thatthe helices contribute in different ways to modulate the energyof proton transfer. The largest helix, Al, opposes the protontransfer through the effect of the helix dipole. The chargedresidues (primary structure) in helix A3 favor the proton transfer,and mask the effect of its helix dipole (secondary structure)which opposes the transfer. The direction of the proton transfersimulated for the activation mechanism is opposite to that assumedin the catalytic process of the thiol protease, and the entireprotein environment opposes the transfer. This supports thespecific role of the ligand in triggering the proton transferas a response to its binding. 相似文献
23.
M. Babu S. Husain M. U. Ahmad S. M. Osman 《European Journal of Lipid Science and Technology》1980,82(2):63-66
The seed oil of Abutilon indicum (Malvaceae) contains three HBr-reactive fatty acids. These are shown to be cis-12,13-epoxyoleic (vernolic) acid, 1.6% 9,10-methylene-octadec-9-enoic (sterculic) acid, 0.9%; as well as 8,9-methylene-heptadec-8-enoic (malvalic) acid, 2.3%. Quantitative results are obtained by combining informations about the HBr-titration, the preparative thin layer separation of oxygenated and non-oxygenated acids, and gas liquid chromatographic analysis. 相似文献
24.
25.
V.P. Astakhov M.O.M. Osman 《International Journal of Machine Tools and Manufacture》1996,36(11):1187-1200
The performance of a self-piloting tool is affected by its design and geometry parameters. These parameters constitute the tool-force system which directly defines quality of the machined holes, tool life and required power. This paper presents an analytical approach to describe the cutting forces in self-piloting drilling. The approach is useful at the level of tool and process design. The subject has been covered in two parts. Part one deals with the analysis of the cutting mechanics employing the shear-zone model with parallel boundaries. The analysis of the continuity condition results in better understanding of the traditional cutting model's characteristics, such as the chip compression ratio and velocity diagram. Based on this analysis and using the thermomechanical model of the work-material resistance to cutting, a cutting-force model is proposed and has been verified experimentally. 相似文献
26.
Vishanth Weerakkody Zahir Irani Habin Lee Nitham Hindi Ibrahim Osman 《Information Systems Management》2016,33(4):331-343
Citizens’ satisfaction is acknowledged as one of the most significant influences for e-government adoption and diffusion. This study examines the impact of information quality, system quality, trust, and cost on user satisfaction of e-government services. Using a survey, this study collected 1518 valid responses from e-government service adopters across the United Kingdom. Our empirical outcomes show the five factors identified in this study have a significant impact on U.K. citizens’ satisfaction with e-government services. 相似文献
27.
Félix Gómez Mármol Christoph Sorge Ronald Petrlic Osman Ugus Dirk Westhoff Gregorio Martínez Pérez 《International Journal of Information Security》2013,12(2):67-82
The recent deployment of smart grids promises to bring numerous advantages in terms of energy consumption reduction in both homes and businesses. A more transparent and instantaneous measurement of electricity consumption through smart meters utilization leads to an enhancement in the ability of monitoring, controlling and predicting energy usage. Nevertheless, it also has associated drawbacks related to the privacy of customers, since such management might reveal their personal habits, which electrical appliances they are using at each moment, whether they are at home or not, etc. In this work, we present a privacy-enhanced architecture for smart metering aimed at tackling this threat by means of encrypting individual measurements while allowing the electricity supplier to access the aggregation of the corresponding decrypted values. 相似文献
28.
Jun Pan Li Na Quan Yongbiao Zhao Wei Peng Banavoth Murali Smritakshi P. Sarmah Mingjian Yuan Lutfan Sinatra Noktan M. Alyami Jiakai Liu Emre Yassitepe Zhenyu Yang Oleksandr Voznyy Riccardo Comin Mohamed N. Hedhili Omar F. Mohammed Zheng Hong Lu Dong Ha Kim Edward H. Sargent Osman M. Bakr 《Advanced materials (Deerfield Beach, Fla.)》2016,28(39):8718-8725
29.
Rasha Osman Irfan Awan Michael E. Woodward 《Simulation Modelling Practice and Theory》2011,19(1):251-270
Databases form the common component of many software systems. However, performance models specifically targeted at the database design have not been extensively studied. In this paper, we propose QuePED – a queueing network performance evaluation model for database designs. QuePED provides for the performance modelling of database design constructs, including active database rules; thus, deviating from current methods that consider database designs as processing demands on the hardware architecture. We present a formal specification of QuePED and describe its application to database designs. Experimental evaluation has shown the ability of QuePED to capture the steady state performance of an implementation of the TPC-C benchmark. 相似文献
30.
Preserving individual privacy when publishing data is a problem that is receiving increasing attention. Thanks to its simplicity the concept of k-anonymity, introduced by Samarati and Sweeney [1], established itself as one fundamental principle for privacy preserving data publishing. According to the k-anonymity principle, each release of data must be such that each individual is indistinguishable from at least k−1 other individuals. 相似文献