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61.
Bahri S Jonsson CM Jonsson CL Azzolini D Sverjensky DA Hazen RM 《Environmental science & technology》2011,45(9):3959-3966
Dihydroxyphenylalanine (DOPA) and similar molecules are of considerable interest in studies of bioadhesion to minerals, solar cells involving titanium dioxide, and biomedical imaging. However, the extent and mechanisms of DOPA adsorption on oxides in salt solutions are unknown. We report measurements of DOPA adsorption on well-characterized rutile (α-TiO?) particles over a range of pH, ionic strength, and surface coverage as well as a surface complexation model analysis establishing the stoichiometry, model surface speciation, and thermodynamic equilibrium constants, which permits predictions in more complex systems. DOPA forms two surface species on rutile, the proportions of which vary strongly with pH but weakly with ionic strength and surface loading. At pH < 4.5 a species involving four attachment points ("lying down") is important, whereas at pH > 4.5 a species involving only two attachment points via the phenolic oxygens ("standing up") predominates. Based on evidence of strong attachment of DOPA to titanium dioxide from single molecule AFM (Lee, H. et al., Proc. Natl. Acad. Sci.2006, 103, 12999-12003) and studies of catechol adsorption, one or more of the DOPA attachments for each species is inner-sphere, the others are likely to be H-bonds. 相似文献
62.
Modaresi J Fathi Nasri MH Rashidi L Dayani O Kebreab E 《Journal of dairy science》2011,94(8):4075-4080
The effects of feeding pomegranate seed pulp (PSP) on milk yield, milk composition, fatty acid profiles of milk fat, and blood metabolites were examined in this study. During a pretrial period, 27 multiparous southern Khorasan (Iran) cross-bred goats were fed a similar diet and dry matter intake, milk yield, and milk composition were recorded. After adaptation and based on pretrial records, the goats were randomly assigned to 1 of 3 experimental diets and were housed in individual stalls. Experimental diets included 0, 6, or 12% of PSP (dry matter basis) and were fed as total mixed rations ad libitum for a 45-d period. Diets were formulated to be isonitrogenous and isocaloric. Supplementation of PSP did not affect dry matter intake or average daily gain of goats. Milk yield was not affected by inclusion of PSP in the diet. Milk fat concentration of goats fed diets with 6 and 12% PSP increased, but milk fat yield, milk protein concentration, and milk solids-not-fat concentration of goats were not affected by diets. Feeding PSP did not affect blood glucose, cholesterol, urea N, triglyceride, or lipoproteins. Feeding goats a diet containing 12% PSP modified the milk fatty acid profile, including conjugated linoleic, punicic, and vaccenic acids. 相似文献
63.
Najib A. Odhah Kamal H. Awadalla Moawad I. Dessouky Fathi E. Abd El-Samie 《International Journal of Wireless Information Networks》2011,18(3):158-170
In this paper, frequency domain pre-equalization (Pre-FDE) is developed for broadband cyclic prefix-code division multiple
access (CP-CDMA) as a single carrier transmission scheme, and for multi carrier-CDMA (MC-CDMA) and orthogonal frequency division
multiplexing (OFDM) as multi carrier transmission schemes. A comparison study is held between these schemes and the traditional
equalization schemes. Experimental results show that pre-equalization improves significantly the performance of the single
and multi carrier communication systems with a very low complexity at the receiver. The comparative study between MIMO pre-equalization
for single carrier systems and for multi carrier systems shows that MIMO pre-equalization for single carrier systems outperforms
that for multi carrier systems in terms of bit error rate (BER) performance since single carrier transmission has more frequency
diversity than multi carrier transmission in the uncoded case. 相似文献
64.
Fathi H. SeongHan Shin Kobara K. Chakraborty S.S. Imai H. Prasad R. 《Selected Areas in Communications, IEEE Journal on》2005,23(11):2182-2193
The coupling of mobility and quality-of-service with security is a challenge that should be addressed in future wireless overlay systems. The mobility of a node can disrupt or even intermittently disconnect an ongoing real-time session because a secure handover must be performed to ensure continuous connectivity. The duration of the such interruptions is called disruption time or handover delay and can heavily affect the user satisfaction. The handover procedure needs to protect its integrity and confidentiality-otherwise, the packets may be rerouted to a malicious node and the legitimate handover may not be performed. The security procedure to ensure this should not lengthen significantly the handover delay to provide good quality real-time services. In this paper, we focus on the network-layer mobility, specifically, on Mobile Internet protocol version 6 (MIPv6) since it is the natural candidate for providing such mobility in future systems. To solve the problem of on-path attackers and prevent leakage of secrets, we propose a security architecture for MIPv6 based on leakage resilient-authenticated key establishment (LR-AKE) protocol and its cooperation with public key infrastructure. The proposed architecture prevents against on-path attackers which was not addressed in the specifications of MIPv6, and also provides robustness against leakage of secret values. Using analytical models, we evaluate MIPv6 handover delay for real-time services. We identify the crucial factors affecting the handover delay among transmission delays of MIPv6, security and LR-AKE messages, queueing delays and en/decryption delays. 相似文献
65.
V Baeyens V Kaltsatos B Boisramé E Varesio JL Veuthey M Fathi LP Balant M Gex-Fabry R Gurny 《Canadian Metallurgical Quarterly》1998,52(1-2):215-220
The aziridinium ion of ethylcholine (AF64A), a cholinergic neurotoxin, was injected into the right striatum of a rat. The unilateral injection of 10 nmol AF64A reduced the activity of choline acetyltransferase (CAT) and the tissue content of acetylcholine (ACh) in the striatum. The striatal contents of dopamine (DA), norepinephrine (NE), 5-hydroxyindoleacetic acid (5-HIAA) and gamma-aminobutyric acid (GABA) were unchanged. These results suggest that the cholinospecificity in the striatal lesion was induced by the 10 nmol dose of AF64A. The number of N-methyl-D-aspartic acid (NMDA) receptors in the striatum treated with 10 nmol AF64A was determined by a specific binding assay using [3H](+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid ([3H]CPP), a selective ligand for NMDA receptors. The number of the NMDA receptors decreased significantly in the injected area. On the other hand, in a microdialysis using normal rats, the perfusion of 50 microM NMDA into the striatum increased ACh release. The perfusion of 100 microM MK801 which is the specific and non-competitive NMDA receptor antagonist, decreased the basal levels of ACh release and blocked NMDA-elicited ACh release. Taken together, the present results strongly suggest that a population of NMDA receptors exists on cholinergic interneurons within the striatum, and it directly regulates ACh release. 相似文献
66.
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68.
A computer program has been developed for the simulation of gas-liquid absorption columns. The calculations are based on known assumptions and methods – the two-film theory. Mass and energy balances together with chemical reactions are carried out for each tray of the column. The results obtained from the simulation procedure are compared with those measured at industrial plants. For the items “rich solution temperature” and “calculated number of trays” the agreement of calculated and measured results are satisfactory. However, for the CO2 and H2S content of the streams only few comparisons could be made due to the fact that no measured values are available. 相似文献
69.
Fathi Moussa Pascale Chretie Pierre Dubois Laurence Chuniaud Michelle Dessante Fran ois Trivin Pierre-Yves Sizaret Viatcheslav Agafonov Ren C olin Henri Szwarc Virginie Greugny Claude Fabre Andr Rassat 《Fullerenes, Nanotubes and Carbon Nanostructures》1995,3(3):333-342
In order to check its possible acute toxicity, C60 was incorporated into living human phagocytes. It was observed that C60 has no influence on the survival of human leukocytes. 相似文献
70.