In the present work the Buildup factor for gamma rays were studied in shields from epoxy reinforced by lead powder and by aluminum powder, for NaI(Tl) scintillation detector size ( ×? ), using two radioactive sources (Co-60 and Cs-137). The shields which are used (epoxy reinforced by lead powder with concentration (10-60)% and epoxy reinforced by aluminum powder with concentration (10-50)% by thick (6mm) and epoxy reinforced by lead powder with concentration (50%) with thick (2,4,6,8,10)mm. The experimental results show that: The linear absorption factor and Buildup factor increase with increase the concentration for the powders which used in reinforcement and high for aluminum powder than the lead powder and decrease with increase thick the shields. It’s for Cs-137 higher than Co-60 source.
This study was conducted for evaluating the cytotoxic effect of heat stable enterotoxin a (STa) produced by enterotoxigenic Escherichia coli on the proliferation of primary cancer cell cultures, obtained from tumor samples that were collected from (13) cancer patients and as follows: (five colon cancer patients, two bladder cancer patients, two breast cancer patients, two stomach cancer patients and two lung cancer patients), and on normal cell line (rat embryonic fibroblast / REF) (in vitro) with the use of different concentrations starting from (1) mg/ml and ending with (0.0002) mg/ml by making two fold serial dilutions by using the 96- well microtiter plate, and in comparison with negative (PBS) and positive (MMC, at concentration
... Show MorePosible interference of vamin with the activity of several antibiotics against E. coli was evaluated in vitro. In MBS- glucose medium, significant growth delay was induced by 8 ug/ml of terramycin (oxytetracycline- polymyxin B) and bactrim (trimethoprim-sulphamethoxazole), and by 16 ug/ml of refocin, lincomycin, and chloramphenicol. Rapid growth inhibition was induced by 32 ug/ml of all an- tibiotic tested separately. Significant inactivation of up to 64 ug/ml of licomycin and bactrim was in- duced by the addition of vamin at a concentration of 1:20 v/v of the medium. This effect was found to be due to the presence of specific amino acids in vamin. Among them is valine, leucine, isoleucine tyrosine, tryptophan, phenylalanine, cysteine, meth
... Show MoreVarious nutritional solutions given to patients contain amino acids. Possible interference of this supplementation with selected aminoglycoside antiboiotics, namely gentamycin and streptomycin was evaluated in vitro. In minimal medium, E.coli was inhibited by gentamycin and by streptomycin. Circumvention of this inhibition was obtained with a mixture of 20 amino acids in the medium. Deletion of amino acids revealved that circumvention. specific amino acids were required for such Deletion of the aromatic amino acids or cysteine abolished the protection against gentamycin and streptomycin, while the deletion of the branched chain amino acids abolished the protection against streptomycin only. Thereonine, on the other hand, appears to be essen
... Show MoreABSTRACT Possible interference of vamin nutritional solution with the activity of several B-lactam antibiotics against E.coli was evaluated in vitro.In Minimal basal salts-glucose medium rapid growth inhibition of sensitive E. coli was induced by 4 µg/ml of ampicillin / cloxaillin, 8 µg/ml of ampicillin, 6 µg/ml of carbencillin, hostacillin, and cephalotin, and by 32 µg/ml of penicillin G and cloxacillin. Significant inactivation of up to 32 µg/ml of carbencillin, cephalotin, penicillin G, and hostacillin was induced by addition of 1:20 v/v vamin. This inactivation was due to the presence of specific amino acids in the mixture. Deletions of amino acids revealed that valine, leucine, isoleucine, tyrosine, tryptophan, phenylalanine, cys
... Show MoreBackground: Irrigation of the canal system permits removal of residual tissue in the canal anatomy that cannot be reached by instrumentation of the main canals so the aim of this study was to compare and evaluate the efficiency of conventional irrigation system, endoactivator sonic irrigation system,P5 Newtron Satelec passive ultrasonic irrigation and Endovac irrigation system in removing of dentin debris at three levels of root canals and to compare the percentage of dentin debris among the three levels for each irrigation system. Materials and methods: Forty extracted premolars with approximately straight single root canals were randomly distributed into 4 tested groups of 10 teeth each. All canals were prepared with Protaper Universal ha
... Show MoreThe Nano compound (Ba1-xSrxTiO3) as (X=0,0.26,0.28,0.30,0.32,0.34) was synthesized by using sol-gel method, the structural properties of result compound were studied by using xray diffraction test (XRD) and scanning electron microscope (SEM). the results were exhibited and by using software indexing to x-ray diffraction pattern that all prepared samples possess tetragonal phase and there is not any other phases were existed. also the substitution process didn't change the phase of compound and increase in (Sr+2) ion concentration leads to decrease lattice parameters (a,c) then the unite cell volume was decreased, as the particle size calculated from Debye-Scherrer and Williamson-Hall equations , and the calculated dens
... Show MoreImpact strength of self-compacted concrete is a field of interest, mostly when the concrete is produced from sustainable materials. This research's main objective is to clarify the ability to use two types of Portland limestone cement (Karasta and Tasluja) in self compacted concrete under impact loading, further to the economic and environmental benefits of the limestone cement. The impact loading was applied by a low-speed test, using the drop ball on concrete. Moreover, the study reveals the resistance of the grids reinforced concrete to impact loading by using polymer grid, and steel grid reinforced concrete slabs. Mixes reinforced by steel mesh had the highest results, indicating that the steel mesh was more robust because it had
... Show MoreEnvironmental sustainability is described as one that avoids the depletion or deterioration of natural resources, while also allowing for the preservation of long-term environmental quality. By practicing environmental sustainability, we may assist to guarantee that the requirements of today’s population are satisfied without risking the capacity of future generations to meet their own needs in the future. Engineers in the field of concrete production are becoming increasingly interested in sustainable development, which includes the utilization of the locally available materials in addition to using the agricultural and industrial waste in construction industry as one of the possib
Background: Polymethylmethacrylate (PMMA) has relatively unsatisfactory mechanical properties such as low flexural strength and impact strength also dimensional instability. Material and method: Zirconium silicate nanoparticles were coated with a layer of trimethoxysilylpropylmethacrylate (TMSPM) before sonication in monomer (MMA) with the percentages 1% and 1.5% by weight then mixed with powder using conventional procedure, (150) samples were prepared and divided into three groups, each group consisted of (50) samples, the first group prepared from PMMA without addition (control), another group with the addition of 1% wt Zrsio4 nanoparticles (experimental) and the third one with 1.5% wt Zrsio4 nanoparticles (experimental). Each group
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