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11.
Khaled M. Al-Aribe George K. Knopf Amarjeet S. Bassi 《Microfluidics and nanofluidics》2012,12(1-4):325-335
Optically manipulating the local pH of a target solution in a microchannel, or reservoir, provides a mechanism for activating and controlling a variety of biological and chemical processes on Lab-on-a-Chip (LOC) devices and micro-total analysis systems (μ-TAS). A microscale pH gradient generator that exploits the light-activated molecular proton pumps found in the purple membranes (PM) of bacteriorhodopsin is described in this paper. The photo-electro-chemical transducer is an ultrathin layer (~13?nm) of oriented PM patches self-assembled on an Au-coated porous substrate. A biotin labeling and streptavidin molecular recognition technique is used to ensure that the extracellular side of all PM patches is attached to the porous substrate enabling unidirectional and efficient transport of ions across the transducer surface. The photo-induced proton pumps generate a flow of ions that produce a measurable change in pH between the separated solutions. The self-assembly procedure is experimentally quantified based on the capacitance characteristics of the bR membranes. The investigation confirms that the transducer is covered with the bR proton pumps at a mass density of 2.33?ng/cm2. Experimental tests also show that the proposed transducer can repeatedly generate pH gradients as high as 0.42 and absolute voltage differences as high as 25?mV when illuminated by an 18?mW, 568?nm light source. Furthermore, the ΔpH is observed to be nonlinear with respect to light intensity and exposure time. The ΔpH of the target solution is sufficient to cause a phenolphthalein indicator dye to change color or an ionic hydrogel micro-valve to expand. 相似文献
12.
El-Mansy M. A. M. Suvitha A. Osman W. Khaled Khaled F. 《Journal of Computational Electronics》2021,20(6):2387-2402
Journal of Computational Electronics - Density functional theory as well as molecular mechanics force field (MMFF94) techniques are used to study intermolecular/intramolecular interactions, band... 相似文献
13.
Rajivgandhi Govindan Nadar Chenthis Kanisha Chelliah Vijayakumar Sekar Alharbi Naiyf S. Kadaikunnan Shine Khaled Jamal M. Alanzi Khalid F. Li Wen-Jun 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(10):3921-3933
Journal of Inorganic and Organometallic Polymers and Materials - The silver oxide nanoparticle was successfully synthesized using floral waste by simple one pot, cost effective method. The complete... 相似文献
14.
Effect of Zn and Pb as alloying elements on the electrochemical behavior of brass in NaCl solutions 总被引:4,自引:0,他引:4
The electrochemical behavior of brasses with various Zn content (5.5–38 mass%) and brass (Cu–38Zn) with different Pb contents (1–3.4 mass%) in 0.6 M NaCl was investigated. The effects of temperature, immersion time, and concentration of chloride ions on the behavior of the different alloys were studied. The pitting corrosion behavior of Cu–Zn alloys and leaded–brass alloys in 0.6 M NaCl solution was also investigated. Open-circuit potential measurements (OCP), polarization techniques and electrochemical impedance spectroscopy (EIS) were used. The results show that the increase in the Zn content increases the corrosion rate of the brass alloys in chloride solutions, while the increase of Pb content in Cu–38Zn–Pb decreases the corrosion rate of the alloy. Long immersion time of the alloys in the aqueous electrolyte improves their stability due to the formation of passive film on the alloy surface. The breakdown potential is shifted to more negative direction with increasing the Zn content, whereas it shifts towards positive values with increasing Pb content. Equivalent circuit model for the electrode/electrolyte interface under different conditions was proposed to illustrate the electrochemical processes taking place at the interface. The electrochemical behavior of the different alloys was discussed in view of the fitting results. 相似文献
15.
Erika Nassar Chris Mulligan Lem Taylor Chad Kerksick Melyn Galbreath Mike Greenwood Richard Kreider Darryn S Willoughby 《Journal of the International Society of Sports Nutrition》2007,4(1):14-13
Melatonin and resistance exercise alone have been shown to increase the levels of growth hormone (GH). The purpose of this
study was to determine the effects of ingestion of a single dose of melatonin and heavy resistance exercise on serum GH, somatostatin
(SST), and other hormones of the GH/insulin-like growth factor 1 (IGF-1) axis. Physically active males (n = 30) and females
(n = 30) were randomly assigned to ingest either a melatonin supplement at 0.5 mg or 5.0 mg, or 1.0 mg of dextrose placebo.
After a baseline blood sample, participants ingested the supplement and underwent blood sampling every 15 min for 60 min,
at which point they underwent a single bout of resistance exercise with the leg press for 7 sets of 7 reps at 85% 1-RM. After
exercise, participants provided additional blood samples every 15 min for a total of 120 min. Serum free GH, SST, IGF-1, IGFBP-1,
and IGFBP-3 were determined with ELISA. Data were evaluated as the peak pre- and post-exercise values subtracted from baseline
and the delta values analyzed with separate three-way ANOVA (p < 0.05). In males, when compared to placebo, 5.0 mg melatonin
caused GH to increase (p = 0.017) and SST to decrease prior to exercise (p = 0.031), whereas both 0.5 and 5.0 mg melatonin
were greater than placebo after exercise (p = 0.045) and less than placebo for SST. No significant differences occurred for
IGF-1; however, males were shown to have higher levels of IGFBP-1 independent of supplementation (p = 0.004). The 5.0 mg melatonin
dose resulted in higher IGFBP-3 in males (p = 0.017). In conclusion, for males 5.0 mg melatonin appears to increase serum
GH while concomitantly lowering SST levels; however, when combined with resistance exercise both melatonin doses positively
impacts GH levels in a manner not entirely dependent on SST. 相似文献
16.
The corrosion inhibition of Cu-Ni alloys was investigated in aqueous chloride solutions using amino acids as environmentally safe materials. The corrosion rate was calculated in absence and presence of the corrosion inhibitor using polarization and impedance techniques. The inhibition efficiency of the different amino acids was also calculated.The experimental results have shown that a simple amino acid like glycine can be used as efficient corrosion inhibitor for the Cu-Ni alloys in neutral chloride solutions. An inhibition efficiency of about 85% could be achieved at very low concentrations of the amino acid (0.1 mM). For low Ni content alloy (Cu-5Ni), 2.0 mM cysteine shows a remarkable high (∼96%) corrosion inhibition efficiency. The experimental impedance data were fitted to theoretical data according to a proposed equivalent circuit model for the electrode/electrolyte interface, and the mechanism of the corrosion inhibition process was suggested. Different adsorption isotherms were tested and the corrosion inhibition process was found to depend on the adsorption of the amino acid molecules and/or the deposition of corrosion products on the alloy surface. The adsorption free energy of cysteine on Cu-5Ni (−37.81 kJ mol−1) reveals a strong physical adsorption of the inhibitor on the alloy surface. 相似文献
17.
A model permits analysis of the influence of temperature on permeate recovery and energy consumption. The proposed model is based on the following assumptions: (1) membrane morphology is temperature-independent; (2) membrane rejection and other transport characteristics of membranes are position-independent; (3) specific water permeability of membranes was based on exponential dependence of viscosity vs. temperature; (4) temperature-dependence depembrane rejection is assumed to be linear. This allows for analyzing the influence of channel geometry, feed concentration, flow rate and temperature on permeate recovery and energy consumption. Calculated data are included. The solutionpresented can be segmented andbuilt into systems for comprehensive techno-economic evaluation of the RO-based process where temperature-dependence of process characteristics has to be considered. 相似文献
18.
ABSTRACTIn this study, an Egyptian siliceous/calcareous sedimentary phosphorite was subjected to beneficiation by unsophisticated economic means. The mineralogical and chemical examination showed that the ore sample is a typical example for the East Mediterranean phosphorites with 21.80% P2O5, 10.93% acid insoluble and 16.61% loss on ignition. The primary crushed sample was classified into three size fractions without any milling and they were separately subjected to an integrated attrition scrubbing study. Screening and classification on the 2.30 mm and 0.071 mm sieves were sequentially introduced with the attrition process. The effect of solid%, attrition speed and time were studied and optimized for each size fraction. Results showed that three products were produced and could be categorized according to their P2O5 content into the coarse tailing (+2.30 mm), the attrition concentrate (?2.30 + 0.071 mm) and the phosphate fines (?0.071 mm). The P2O5 contents of these products reached 12.24%, 28.72% and 18.77%, with P2O5 distribution reached 6.74%, 51.75% and 41.51%, respectively. A global P2O5 of 28.72% was obtained with a recovery of about 52%. A tentative flow-sheet for the whole process was postulated. 相似文献
19.
Colin?WilbornEmail author Jacqueline?Beckham Bill?Campbell Travis?Harvey Melyn?Galbreath Paul?La Bounty Erika?Nassar Jennifer?Wismann Richard?Kreider 《Journal of the International Society of Sports Nutrition》2005,2(2):4-31
Obesity and its associated disorders are a growing epidemic across the world. Many genetic, physiological, and behavioral
factors play a role in the etiology of obesity. Diet and exercise are known to play a valuable role in the treatment and prevention
of obesity and associated disorders such as hypertension, heart disease, and diabetes. Therefore, the purpose of this review
is to examine the prevalence, etiology, consequences, and treatment of obesity. 相似文献
20.
Sybren de Kinderen Khaled Gaaloul Henderik A. Proper 《Software and Systems Modeling》2014,13(3):1043-1057
The ArchiMate modelling language provides a coherent and a holistic view of an enterprise in terms of its products, services, business processes, actors, business units, software applications and more. Yet, ArchiMate currently lacks (1) expressivity in modelling an enterprise from a value exchange perspective, and (2) rigour and guidelines in modelling business processes that realize the transactions relevant from a value perspective. To address these issues, we show how to connect e \(^{3}\) value, a technique for value modelling, to ArchiMate via transaction patterns from the DEMO methodology. Using ontology alignment techniques, we show a transformation between the meta models underlying e \(^{3}\) value, DEMO and ArchiMate. Furthermore, we present a step-wise approach that shows how this model transformation is achieved and, in doing so, we also show the of such a transformation. We exemplify the transformation of DEMO and e \(^{3}\) value into ArchiMate by means of a case study in the insurance industry. As a proof of concept, we present a software tool supporting our transformation approach. Finally, we discuss the functionalities and limitations of our approach; thereby, we analyze its and practical applicability. 相似文献