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Butyrate regulates leptin expression through different signaling pathways in adipocytes
Mohamed Mohamed Soliman,Mohamed Mohamed Ahmed,Alaa-eldin Salah-eldin,Abeer Abdel-Alim Abdel-Aal 대한수의학회 2011 Journal of Veterinary Science Vol.12 No.4
Leptin is an adipocytokine that regulates body weight, and maintains energy homeostasis by promoting reduced food intake and increasing energy expenditure. Leptin expression and secretion is regulated by various factors including hormones and fatty acids. Butyrate is a short-chain fatty acid that acts as source of energy in humans. We determined whether this fatty acid can play a role in leptin expression in fully differentiated human adipocytes. Mature differentiated adipocytes were incubated with or without increasing concentrations of butyrate. RNA was extracted and leptin mRNA expression was examined by Northern blot analysis. Moreover, the cells were incubated with regulators that may affect signals which may alter leptin expression and analyzed with Northern blotting. Butyrate stimulated leptin expression, and stimulated mitogen activated protein kinase (MAPK) and phospho-CREB signaling in a time-dependent manner. Prior treatment of the cells with signal transduction inhibitors as pertusis toxin, Gi protein antagonist, PD98059 (a MAPK inhibitor), and wortmannin (a PI3K inhibitor) abolished leptin mRNA expression. These results suggest that butyrate can regulate leptin expression in humans at the transcriptional level. This is accomplished by: 1) Gi protein-coupled receptors specific for short-chain fatty acids, and 2) MAPK and phosphatidylinositol-3-kinase (PI3K) signaling pathways.
Identifying Cylinder Liner Wear using Precise Coordinate Measurements
Salah Hamed Ramadan Ali,Hassan Hassan Mohamed,Mohamed Kamal Bedewy 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.5
This paper aims at exploiting the accurate precise measurements of CMM machine in exploring and investigating the wear happening between contacting solid surfaces. For instance, excessive wear, if detected by the CMM measurements, in a cylinder bore of an internal combustion engine can dramatically affect its performance quality, sealing function, scheme of lubrication, and eventually its service life span. In such case, the finger print would be the original design GD&T tolerances. Widely spread availability of CMM machines at a reasonable cost may make the applicability of this novel technique of wear detection feasible. In this work, precise and accurate measurements of deviations in roundness, straightness, and concentricity in a cylinder bore of an air cooled Automotive Diesel Engine dismantled for an overhaul using a CMM machine have been executed and analyzed to validate this technique. Thus, the results have been presented, discussed, analyzed and interpreted in order to evaluate the status of the engine during operation. Locations of remarkable deviations representing aggressive wear happenings in the cylinder bore are detected and investigated. The measurements, within the limits of uncertainty attributes, could reflect the performance quality of the engine, the suitability of the applied scheduled maintenance plan, and may also point at possible adverse operating conditions contributed to this wear. In the light of the findings, recommendations may thus be drawn and offered to the engine designer to improve his design. For instance, surface treatments and coatings could be preferably changed, or an innovative constructional modification may be suggested to homogenize the wear occurrence in the cylinder bore during operation. This may extend the operating life span of the cylinder and in turn reduces the maintenance expenses. This novel technique for the wear development recalling proved to be successful and reliable tool to diagnose the root causes of the wear aggression occurrence.
Mohamed Brayek,Zied Driss,Mohamed Ali Jemni,Ali Damak,Mohamed Salah Abid 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1
Combustion characteristics and emission in spark-ignition engines could be enhanced using hydrogen as supplementary fuel. However, its production, storage, and introduction in the combustion chamber face several challenges. To overcome the necessity of a storage device, a conventional electrolyser was used to produce a hydrogen-oxygen mixture (hydroxygen). The produced hydroxygen bubbles are characterized by their macro and nanometric size. In the present work, gasoline was on top of the water in the electrolyser. Therefore, hydroxygen nanobubbles are diffused in both water and gasoline. Combustion analysis was carried out for different engine speeds. An improvement in brake torque and a reduction in fuel consumption, HC, CO, and CO 2 emissions have been witnessed in the engine during test performance. However, the emission analysis shows a slight increase in NO x emission. Finally, this disadvantage could be neglected compared to the improvements that come with the use of hydroxygen nanobubble gasoline blends.
Salah Mohamed El-Bahy,Zeinhom Mohamed El-Bahy 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.8
New porous chelating resin beads CPN-IDA were prepared by the reaction of poly (acrylonitrile-co-N,N'- methylenebisacrylamide) with etheylenediamine and sodium chloroacetate, respectively. The composition and morphology of the chelating resin was characterized by Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA and DrTGA), scanning electron microscopy (SEM), surface area measurements by N2 adsorption (SBET) and water regain (w%). Batch adsorption experiments were employed to study the impact of some factors that control the adsorption of metal ions including solution pH, concentration of metal ions, contact time and the temperature of the solution. Batch sorption results showed that the chelating resin had high affinity towards Cu(II), Cd(II) and Pb(II). The saturated adsorption capacity at 25 oC was 2.43, 1.93 and 1.45mmolg−1 resin for Cu(II), Cd(II) and Pb(II), respectively. Among the empirical isotherm models, the equilibrium adsorption results were obviously fitted with Langmuir model. The kinetics was analyzed using pseudo-first-order, pseudo-second-order, and intra-particle diffusion equations. The adsorption kinetic data were well elucidated with pseudo-second-order kinetic model. Thermodynamic parameters were calculated for the uptake of the metal ions under study and it was found to be a spontaneous process. Moreover, the adsorption of metal ions has been studied using column technique. The regeneration of CPN-IDA was experimentally performed by using nitric acid. The chelating resin was used repeatedly for five times with a little decrease in sorption of metal ions.
Electronic structure of p-type transparent conducting oxide CuAlO2
Salah Mohamed,Yoon Joonseok,El-Desoky Mohamed M.,Hussain Zahid,Ju Honglyoul,Mo Sung-Kwan 한국물리학회 2022 Current Applied Physics Vol.39 No.-
Copper-based delafossite oxides are excellent candidates for the p-type transparent conducting oxide (TCO), which is essential in realizing transparent semiconductor applications. Using angle-resolved photoemission spectroscopy (ARPES), we report the low-energy electronic structure of CuAlO2. We found that the band structure near the valence band top is characterized by hole bands with their maxima along the Brillouin zone boundary. Furthermore, the effective masses along the Γ–M and Γ–K directions were found to be (0.6 ± 0.1) m0 and (0.9 ± 0.1) m0, respectively, which impose an important benchmark against the existing band calculations.
( Khaled Salah Mohamed ),( Sayed Kaoud Abd-elshafy ),( Ali Mahmoud El Saman ) 대한통증학회 2017 The Korean Journal of Pain Vol.30 No.3
Background: Surgeon satisfaction and patient analgesia during the procedure of laparoscopic surgery are important issues. The aim of this work was to study if an intrathecal (IT) Bupivacaine combined with Magnesium sulfate may or may not provide good surgeon satisfaction in addition to improvement of intraoperative and postoperative analgesia. Methods: Sixty female patients were enrolled in this prospective, randomized, double-blind controlled clinical trial study. All patients were operated for gynecological laparoscopic surgery under spinal anesthesia. Patients were divided into two groups (Bupivacaine and Magnesium). Group Bupivacaine (30 patients) received intrathecal Bupivacaine 0.5% only (15 mg), while 30 patients in group Magnesium received intrathecal Bupivacaine (15 mg) in addition to intrathecal Magnesium sulfate (50 mg). The sensory block level, the intensity of motor block, the surgeon satisfaction, the intraoperative visual analog scale (VAS) for pain assessment, the postoperative VAS, and side effects were recorded during the intraoperative period and within the first 24 hours after surgery in the post-anesthesia care unit. Results: Surgeon satisfaction, intraoperative shoulder pain, postoperative pain after 2 h, and perioperative analgesic consumption (ketorolac) were significant better in group Magnesium than in group Bupivacaine. (P < 0.05). The onset of motor and sensory blocks was significant longer in group Magnesium than the other one. The incidence of PONV, pruritus and urinary retention was insignificant statistically between both groups. Conclusions: Magnesium sulfate if used intrathecally as an adjuvant to Bupivacaine would provide a better surgeon satisfaction and would improve the analgesic effect of spinal anesthesia used for gynecological laparoscopic surgery. (Korean J Pain 2017; 30: 207-13)