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951.
Angiotensin converting enzyme‐inhibitory activity and antimicrobial effect of fermented camel milk (Camelus dromedarius)
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Omar A Alhaj Ali A Metwalli Elsayed A Ismail Hatem S Ali Abdulrahman S Al‐Khalifa Ara D Kanekanian 《International Journal of Dairy Technology》2018,71(1):27-35
This study aimed to determine the angiotensin converting enzyme‐inhibitory activity and antimicrobial effect of fermented camel milk. Samples were prepared either using Lactobacillus acidophilus and Streptococcus thermophilus or Lactobacillus helveticus and Str. thermophilus and labelled as S1 and S2, respectively. The IC50 values of S1 and S2 samples ranged between 113–200 and 70–133 μg/mL, respectively. The antimicrobial effects of S1 and S2 samples against Bacillus cereus, Salmonella Typhimurium and Staphylococcus aureus were apparent after 12 h of incubation and continued until 15 days of storage, whereas unfermented camel milk exhibited no antimicrobial effects against any of the tested pathogens. 相似文献
952.
M. Ismail Y. Zhao X.B. Yu J.F. MaoS.X. Dou 《International Journal of Hydrogen Energy》2011,36(15):9045-9050
In this study, we report the hydrogen absorption/desorption properties and reaction mechanism of the MgH2-NaAlH4 (4:1) composite system. This composite system showed improved dehydrogenation performance compared with that of as-milled NaAlH4 and MgH2 alone. The dehydrogenation process in the MgH2-NaAlH4 composite can be divided into four stages: NaAlH4 is first reacted with MgH2 to form a perovskite-type hydride, NaMgH3 and Al. In the second dehydrogenation stage, the Al phase reacts with MgH2 to form Mg17Al12 phase accompanied with the self-decomposition of the excessive MgH2. NaMgH3 goes on to decompose to NaH during the third dehydrogenation stage, and the last stage is the decomposition of NaH. Kissinger analysis indicated that the apparent activation energy, EA, for the MgH2-relevent decomposition in MgH2-NaAlH4 composite was 148 kJ/mol, which is 20 kJ/mol less than for as-milled MgH2 (168 kJ/mol). X-ray diffraction patterns indicate that the second, third, and fourth stages are fully reversible. It is believed that the formation of Al12Mg17 phase during the dehydrogenation process alters the reaction pathway of the MgH2-NaAlH4 (4:1) composite system and improves its thermodynamic properties. 相似文献
953.
Mostafa Ghasemi Samaneh Shahgaldi Manal Ismail Byung Hong Kim Zahira Yaakob Wan Ramli Wan Daud 《International Journal of Hydrogen Energy》2011,36(21):13746-13752
This paper evaluated the oxygen reduction reaction (ORR) in a microbial fuel cell (MFC) system by using chemically and physically activated electrospun carbon nanofibers (ACNFs) in an MFC and comparing their performance with that of plain carbon paper. The chemical and physical activation was carried out by KOH reagents and CO2 gas to increase the electrode surface area and the catalytic activity. As a result, it was found that the MFC with the chemically activated carbon nanofibers (ACNFs) exhibited better catalytic activity than that of the physically activated ACNFs. Chemically ACNFs with 8 M KOH were found to be one of the most promising candidates for the ORR and could generate up to 3.17 times more power than that of the carbon paper. The ACNFs with 8 M KOH exhibited 78% more power generation than that of the physically activated ACNFs and exhibited 16% more power generation than the chemically activated ACNFs with 4 M KOH. The power per cost of ACNFs with 8 M KOH is 2.65 times greater than that of the traditionally used platinum cathode. Thus, ACNFs are a good alternative catalyst to Pt for MFCs. 相似文献
954.
Nuru Gambo Ilias Said Radzi Ismail 《International Journal of Construction Education and Research》2017,13(1):24-46
Performance of small-scale building construction contract business poses a challenge to the sustainable development of the construction industry, particularly in developing countries like Nigeria. Small-scale construction contract business plays an important role in the economic development of any nation. In Nigeria, small-scale construction contract business has a tremendous role in the development of rural areas. This study assesses the mediation effects of client support with advance payment on cost factors that affect performance of small-scale contract businesses in Nigeria. The study identified three factors that affect cost performance of construction projects in developing countries: cash flow problems, effects of fraudulent practices, and effects of the nature of construction environments. In total, 550 survey questionnaires were administered to stakeholders in the Nigerian construction industry. Stratified proportionate random sampling method was used for the selection of respondents and 387 questionnaires were returned, with 357 used in the analysis. 相似文献
955.
Hasan Huseyin Erdem Ahmet Dagdas Suleyman Hakan Sevilgen Burhanettin Cetin Ali Volkan Akkaya Bahri Sahin Ismail Teke Cengiz Gungor Selcuk Atas 《Applied Thermal Engineering》2010,30(2-3):181-187
In a conventional coal-fired power plant, which is only designed for electricity generation, 2/3 of fuel energy is wasted through stack gases and cooling water of condensers. This waste energy could be recovered by trigeneration; modifying the plants in order to meet district heating/cooling demand of their locations. In this paper, thermodynamical analysis of trigeneration conversion of a public coal-fired power plant, which is designed only for electricity generation, has been carried out. Waste heat potentials and other heat extraction capabilities have been evaluated. Best effective steam extraction point for district heating/cooling system; have been identified by conducting energetic and exergetic performance analyses. Analyses results revealed that the low-pressure turbine inlet stage is the most convenient point for steam extraction for the plant analyzed. 相似文献
956.
Yeek Chia Ho Norli Ismail Abbas F. M. Alkarkhi Norhashimah Morad 《Canadian Metallurgical Quarterly》2010,136(11):1267-1276
The performance of two flocculants on turbidity reduction was studied. The two flocculants were: a biopolymeric flocculant which was extracted from fruit waste and a commercial industrial flocculant. The effect of the flocculants’ average molecular weight on turbidity treatment, the treatment efficiency of both flocculants and the flocculants’ degradability were investigated. Response surface methodology was carried out using Box Behnken design to find the optimal pH, cation concentration, and flocculant dosage to maximize the turbidity reduction. The results showed that the maximum turbidity reduction by industrial flocculant occurs between pH 7.5 and pH 8.2, cation concentration between 0.02 and 0.06 mM, and industrial flocculant dosage between 6.5 and 8.0 mg/L. While with biopolymeric flocculant, maximum turbidity reduction occurred between pH 4.6 and pH 7.5, cation concentration between 0.60 and 0.95 mM, and biopolymeric flocculant dosage between 4 and 6 mg/L. 相似文献
957.
Hilda Ismail Rute Madeira Lau Fred van Rantwijk RogerA. Sheldon 《Advanced Synthesis \u0026amp; Catalysis》2008,350(10):1511-1516
A fully enzymatic methodology for the resolution of chiral amines has been demonstrated. Candida antarctica lipase B (CaLB)‐catalyzed acylation with N‐methyl‐ and N‐phenylglycine, as well as analogues having the general formula R1 X CH2CO2R2 (R1=Me, Ph; X=O, S) afforded the corresponding enantioenriched amides, which were subsequently enzymatically hydrolyzed. Surprisingly, CaLB also proved to be the catalyst of choice for this latter step. The heteroatom in the acyl donor profoundly influences both the enzymatic acylation and deacylation; the O‐substituted reagents performed best with regard to enantioselectivity as well as reaction rate in synthesis and hydrolysis. 相似文献
958.
Volkan Cecen Mehmet Sarikanat Yoldas Seki Hasan Yildiz Ismail H. Tavman 《Polymer Composites》2008,29(3):262-273
The primary purpose of the study was to investigate the anisotropic behavior of different noncrimp stitched fabric reinforced polyester composites. The effects of geometric variables on composite structural integrity and strength are illustrated. Hence, tensile, three‐point bending flexural and short beam shear tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in noncrimp stitched fabric. The remark, based on the observations while tensile testing, is that the stress–strain curves of polyester based composites were linear in the direction of fibers. However, in the matrix dominated orientations nonlinear relation between the stress and the strain was observed. Another aim of the present work was to investigate the interaction between glass fiber and polyester matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the interaction between glass fiber and polyester and were interpreted in an attempt to explain the instability of polyester resin–glass fiber interfaces. It was concluded that the polymer was either deposited between adjacent fibers or as widely separated islands on the fiber surface. Infrared spectra of the cured polyester and its glass fiber composite were obtained by Fourier transform infrared spectroscopy. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers 相似文献
959.
Naghmouchi K Fliss I Drider D Lacroix C 《Journal of Bioscience and Bioengineering》2008,105(5):513-517
Pediocin PA-1 production by Pediococcus acidilactici UL5 cells immobilized in kappa-carrageenan/locust bean gum gel beads was studied during repeated-cycle batch (RCB) culture with pH control in Man Rogosa and Sharpe (MRS) broth supplemented with 1% glucose and whey permeate (SWP) medium. The pediocin PA-1 production by free P. acidilactici cells pH-controlled batch culture has reached 2048 and 4096 AU ml(-1) after 11 and 12 h of incubation, with volumetric productivities of 187 and 342 AU ml(-1) h(-1) in SWP and MRS media, respectively. In RCB culture, immobilized cells reached a maximum concentration of 7.3+/-0.2 x 10(10) and 4.3+/-0.9 x 10(10) cfu g(-1) of beads in MRS and SWP media, respectively. The maximum pediocin PA-1 activity obtained during RCB fermentation was 4096 AU ml(-1); it was attained after only 0.75 and 2 h of incubation in MRS and SWP media, respectively. The corresponding volumetric productivities were 5461 and 2048 AU ml(-1) h(-1). Pediocin PA-1 production in the RCB culture was highly stable over 12 fermentation cycles carried out over 3 d in SWP media. 相似文献
960.
Yusuf Kayalı Ismail Ucun Kubilay Aslantaş 《Journal of Failure Analysis and Prevention》2009,9(3):288-294
Tapered roller bearings, which are also known as angular-contact bearing, are suitable for supporting radial and axial loads.
The more frequent types of defects in such bearings are caused by contact fatigue in these machine components, and this examination
focuses on a contact fatigue failure in a tapered rolling bearing. The examination included visual inspection, microscopic
analysis (optical and scanning electron microscope), and microhardness measurements. These measurements were conducted to
help understand the failure mechanisms. Based on the results of visual examination and microstructure and fracture surface
analysis, it was determined that the tapered roller bearing failed by contact fatigue that was caused by overloading of the
bearing. 相似文献