2,433 research outputs found
Evaluating the mechanical properties of Epoxy resin with Fly ash and Silica fume as fillers
Composite material consists of merging two composite materials or more are different in mechanical and physical properties, in this study a composite polymeric material has been prepared, it's mainly used in treatment of cracks that happened in concrete slabs, by using Epoxy resin as a major substance in work while the filler were the Fly ash and Silica fume. Samples were prepared by hand-made molds has special dimensions according to the American Standards for Testing and Materials (ASTM) and adding each filler separately with different ratios as ( 10%, 20%, 30 %, 40% and 50%), then studying the mechanical properties of these material like tensile, hardness, compression, impact and bending properties. Key Words : Epoxy resin, Fly ash, Silica fume, fillers
Microbial Contamination of Date Rutab Collected from the Markets of Al-Hofuf City in Saudi Arabia
The microbial contamination of 60 samples from six date cultivars in the rutab stage purchased from different retail outlets in AL-Hofuf City, Saudi Arabia was studied. All samples were found contaminated with aerobic mesophilic bacteria at loads in the order 102 to 105 cfu/cm2 with some significant differences among varieties that can be attributed to differences in the weather conditions during rutab season. Also all samples, except only one, were contaminated with molds and yeasts at loads in the order 102 to 103 cfu/cm2. Potentially pathogenic Staphylococcus aureus was detected in 57 samples and A. flavus/parasiticus in 13 samples, while coliforms were detected in 39 samples
Efecto del injerto poli-quitosano (N-L-lactide) sintetizado sobre el material genético humano
Introduction: Chitosan is one of the natural polymers can generally consider as a biocompatible and biodegradable polycationicpolymer, which has minimum immunogenicity and low cytotoxicity. Therefore, chitosan and its derivatives may represent potentially safe cationic carriers for use in gene delivery. Materials andMethods: Chitosan with 90.1 DD% obtained by deacetylation ofchitin extracted from local shrimp shells. Graft copolymerizationof L-lactide onto chitosan was carried out at room temperature byring opening polymerization under a nitrogen atmosphere to prepare chitosan-g-poly (N-lactide) graft copolymer. It was obtainedin good yield and characterized by FTIR. The samples purity andconcentration were detected using both Nanodrop UV-spectroscopy and agarose gel electrophoresis techniques. The humanheat shock proteins gene, hsp-70, was used as a model of humangenes to study the effect of chitosan-g-poly (N-lactide) graft copolymer. Results and Discussion: The results revealed that chitosan-g-poly (N-lactide) graft copolymers had safety effect on theDNA, and binding with it. the human heat shock proteins gene,hsp-70, was used as a model of human genes to study the effectof chitosan-g-poly (N-lactide) graft copolymer, it shows a goodbinding ability the human gene, implies that it might be used inbiomedical applications in the future. Conclusions: Grafting ofL-lactide onto chitosn by ring opening polymerization was confirmed by FTIR. The repared polymer hase safety effectson human DNA and genes. The chitosan-g-poly (N-lactide) graftcopolymer has shown highly efficiency to electrostatic interactionwith human DNA and gene, implying that it is suitable to be usedas DNA and gene delivery
Saudi mothers' preferences about breaking bad news concerning newborns: a structured verbal questionnaire
<p>Abstract</p> <p>Background</p> <p>Breaking bad news (BBN) to parents whose newborn has a major disease is an ethical dilemma. In Saudi Arabia, BBN about newborns is performed according to the parental preferences that have been reported from non-Arabic/non-Islamic countries. Saudi mothers' preferences about BBN have not yet been studied. Therefore, we aimed to elicit the preferences of Saudi mothers about BBN concerning newborns.</p> <p>Methods</p> <p>We selected a convenience sample of 402 Saudi mothers, aged 18-50 years, who had no previous experience with BBN. We selected them via a simple number-randomization scheme from the premises of a level III Saudi hospital between October of 2009 and January of 2011. We used a hypothetical situation (BBN about trisomy 21) to elicit their preferences about BBN concerning newborns via a structured verbal questionnaire composed of 12 multiple-choice questions. We expressed their preferences as percentages (95% confidence interval), and we used the Kendall's W test (W) to assess the degree of agreement in preferences.</p> <p>Results</p> <p>The Saudi mothers preferred that BBN be conducted with both parents together (64% [60-69]), albeit with weak levels of agreement (W = 0.29). They showed moderate agreement in their preferences that BBN should be conducted early (79% [75-83], W = 0.48), in detail (81% [77-85], W = 0.52), in person (88% [85-91], W = 0.58), and in a quiet setting (86% [83-90], W = 0.53). With extremely weak agreement, they preferred to have a known person present for support during BBN (56% [51-61], W = 0.01), to have close bodily contact with their babies (66% [61-70], W = 0.10), and to have no another patients present (64% [59-68], W = 0.08). They showed moderate levels of agreement in their desires to detail, in advance, their preferences about process of BBN by giving a reversible, written informed consent that could be utilized for guidance, if needed (80% [76-84], W = 0.36).</p> <p>Conclusions</p> <p>In our experience, Saudi mothers' preferences about BBN concerning newborns are varied, suggesting that a "one-size-fits-all" approach is inappropriate. A reversible, written informed consent detailing their preferences about BBN that would be kept in their medical records and utilized for guidance, if needed, may be the best solution, given this level of diversity. These findings merit further study.</p
Catalyzed and Promoted Direct Reaction of Ethyl Chloride with Silicon Using Stirred-Bed Reactor
In this paper a stirred-bed performed of the copper catalyzed synthesis of ethylchlorosilanes from silicon and ethyl chloride was described. A Si-catalyst mixture prepared by reaction of CuCl and Si was employed. The compositions of products were mainly ethyltrichlorosilane, diethyldichlorosilane, and ethyldichlorosilane and mainly depended on the extent of Cu in the mixture and the reaction temperature. A promoting effect on the extent of adsorption was observed on the addition of certain additives. The kinetic data revealed the direct depended of the reaction rate on C2H5Cl pressure
Determination Of Aerosol Optical Thickness From Spectral Sky Transmittance.
The objective of this study is to test the feasibility of the proposed technique for retrieving spectral aerosol optical thickness (AOT) from the spectral transmittance measurements. The measurements have been acquired around Penang Island, Malaysia. Ground-based measurements were made with a handheld spectroradiometer. The measured spectral transmittance data were then converted to AOT values 6 spectral bands between 400 and 900 nm. Spectral AOT maps were generated using Kriging interpolation method for the 6 spectral bands. Air quality map was produced using this technique
Risky Driving Behaviours among Medical Students in Erbil, Iraq
Objectives: This study aimed to assess risky driving behaviours among medical students in Erbil, Iraq, and to explore the relationship between risky driving behaviours and perceptions of risky driving. Methods: This self-administered questionnaire-based survey was conducted from January to May 2014 among a random sample of 400 medical students at Hawler Medical University in Erbil. The questionnaire was designed to assess the frequency of engagement in 21 risky driving behaviours, the perceived risk of each behaviour and the preference for each behaviour as ranked on a 5-point scale. Results: A total of 386 students responded to the survey (response rate: 96.5%). Of these, 211 reported that they currently drove a vehicle (54.7%). Drivers most frequently engaged in the following behaviours: playing loud music (35.9%), speeding (30.4%), allowing front seat passengers to not wear seat belts (27.9%) and using mobile phones (27.7%). Least frequent driving behaviours included not stopping at a red light (3.9%), driving while sleepy (4.4%), driving after a mild to moderate intake of alcohol (4.5%) and drunk driving (6.4%). Mean risky driving behaviour scores were significantly higher among males (P <0.001) and those who owned a car (P = 0.002). The mean risk perception score was higher among >20-year-olds (P = 0.028). There was a significant positive relationship between the preference for risky behaviours and risky driving behaviours (beta = 0.44; P <0.001). Conclusion: Medical students in Erbil reported high frequencies of several serious risky driving behaviours. The preference for risky behaviours was found to be an important predictor of risky driving behaviours among medical students in Erbil
PM10 Retrieval From Spectroradiometer Measurements.
This study attempts to determine the aerosol optical thickness (AOT) from spectroradiometer data. The spectroradiometer is used to measure the atmospheric transmittances in a wide spectrum over Penang Island, Malaysia
The Effects of Disinfectants on Dimensional Accuracy and Surface Quality of Impression Materials and Gypsum Casts
Abstract Background: The study aimed to evaluating the effect of disinfecting impression materials on the dimensional accuracy and surface quality of the resulting casts
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