557 research outputs found

    An analysis of grammatical and associated errors found in the writing of third grade Saudi male students in four high schools in the city of Riyadh

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    The main aim of the thesis is to identify and analyse the types and frequency of grammatical, lexical and general linguistic errors made in the Arabic composition writings of the third year high school students in the city of Riyadh, Saudi Arabia. This study is to provide information that can be utilised in the improvement of teaching of the grammatical rules of the Arabic language to public school students. The approach is descriptive, analytical and classificatory.Chapter one deals with the research problem, aims and significance of the study, and also discusses the limitations of the study.Chapter two reviews the background to Arabic grammar in the Saudi educational system in the country, particularly in the secondary school system.Chapter three is an extensive literature review on the background of grammatical errors and Arabic grammatical rules.Chapter four examines the prevalence of grammatical errors, their causes and complaints.Chapter five reviews the efforts and attempts to simplify Arabic grammatical rules as a reaction to the dilemma of Arabic grammar and the prevalence of the grammatical errors.Chapter six deals with the research design and methodology of the study undertaken.Chapter seven presents and analysis the main results of this study. It starts with frequency of the grammatical errors and the percentage of the students who committed grammatical errors. This chapter also presents the frequency of types of errors for each grammatical component and finally it highlights the general linguistic errors found in the students' writings.Chapter eight, which is the final chapter, is devoted to a conclusion and implications for practice and future research

    Investigating xanthine oxidase toxicity models in cultured cerebellar granule neurons

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    In the last few decades, evidence has been accumulating for a role for xanthine oxidoreductase (XOR)-generated toxic reactive oxygen species (ROS) in a variety of pathological conditions that affect different organ systems. This enzyme in mammals exists in two inter-convertible forms: xanthine dehydrogenase (XDH) (the predominant intracellular form under physiological conditions) and xanthine oxidase (XO). A combination of XO and its oxidizable substrate xanthine (X) (or hypoxanthine (HX)) is widely used as a model to produce ROS and to study their effects in a variety of cell culture studies. However, the effect of the combination of XOR and the reduced nicotinamide adenine dinucleotide (NADH) in cell cultures is much less studied. NADH is another oxidizable substrate for XOR that binds to a different site on the enzyme from that of X binding. The aim of this project was to investigate some aspects of the in vitro toxicity of XOR, which might provide more insights into its in vivo toxicity. The main investigation was a comparison between the well studied X / XO and the much less studied NADH / XO toxicity models. Also, secondary studies were undertaken to investigate those aspects of X / XO toxicity where there are uncertainties about them. These studies were performed using primary cell cultures. Cell cultures are now widely used to study different diseases, and although they have their drawbacks, they have their advantages over the in vivo studies. For this project, primary cultures of cerebellar granule neurons (CGNs) were used. In the beginning, some problems were encountered with CGNs. The main problem was the immediate damage induced to the neurons (including those in the control groups) at the intervention/experiments day (i.e. day 8 or 9 after plating) by manipulating the cultures (i.e. aspirating the culture medium, adding treatment and control vehicles, and adding the restoration medium). After several months of investigation, it was serendipitously discovered that the immediate damage seen in the neurons (including those in the control groups) when they are manipulated at the experiments/intervention day was due to glutamate excitotoxicity (through activating its N-methyl-D-aspartate (NMDA) receptors). The source of glutamate was the fresh serum which is present at 10% V/V in the fresh culture medium that is added to the cultures at that day. After solving this problem, it was possible to conduct reliable experiments to investigate XO toxicity models. Regarding investigating XO toxicity, it was found that both of the X / XO and NADH / XO combinations were toxic to cultures of CGNs. However, the concentration of NADH needed to cause the toxicity was much higher than that of the other substrate, X, which is in agreement with previous cell-free experiments that showed that NADH is a much weaker substrate than X for the bovine milk XO used here. Blocking the site of X binding on XO prevented X / XO toxicity, but did not prevent NADH / XO toxicity. On the other hand, blocking the site of NADH binding prevented both X / XO and NADH /XO toxicities. Another difference between the two systems was that deactivating either superoxide or hydrogen peroxide (both are ROS) generated by XO prevented NADH / XO toxicity, whereas although deactivating hydrogen peroxide prevented X / XO toxicity, deactivating superoxide generated from this combination did not. In the NADH / XO system, an extracellular metal contaminant (likely contaminating XO powder/preparation) seemed to be involved in the toxicity. The two toxicity models were similar in the mediation of toxicity by intracellular iron ion. In X / XO toxicity, although superoxide generated extracellularly from the combination has no role in the toxicity, intracellularly produced superoxide seemed to play a role. Conclusions: 1. Culturing/experimental conditions have been optimised for viability studies in CGNs cultures. 2. The combination of NADH and XO induces damage to CGNs, where although blocking the NADH binding site prevents this damage, blocking the X binding site does not. It is feasible that the oxidation of NADH by some forms of XOR (other than the one used here) that are known to be very efficient in oxidizing NADH might produce in vivo toxicity. 3. A possibility raised by this study is that a metal (like the metal contaminant proposed to play a role in NADH / XO toxicity in this study) might contribute to XOR toxicity in vivo. 4. Intracellular superoxide often mediates XOR toxicity. 5. The results add support to many previous studies which suggested that intracellular hydroxyl radical (or a similar species) is involved in XOR toxicity

    An analysis of grammatical and associated errors found in the writing of third grade Saudi male students in four high schools in the city of Riyadh

    Get PDF
    The main aim of the thesis is to identify and analyse the types and frequency of grammatical, lexical and general linguistic errors made in the Arabic composition writings of the third year high school students in the city of Riyadh, Saudi Arabia. This study is to provide information that can be utilised in the improvement of teaching of the grammatical rules of the Arabic language to public school students. The approach is descriptive, analytical and classificatory.Chapter one deals with the research problem, aims and significance of the study, and also discusses the limitations of the study.Chapter two reviews the background to Arabic grammar in the Saudi educational system in the country, particularly in the secondary school system.Chapter three is an extensive literature review on the background of grammatical errors and Arabic grammatical rules.Chapter four examines the prevalence of grammatical errors, their causes and complaints.Chapter five reviews the efforts and attempts to simplify Arabic grammatical rules as a reaction to the dilemma of Arabic grammar and the prevalence of the grammatical errors.Chapter six deals with the research design and methodology of the study undertaken.Chapter seven presents and analysis the main results of this study. It starts with frequency of the grammatical errors and the percentage of the students who committed grammatical errors. This chapter also presents the frequency of types of errors for each grammatical component and finally it highlights the general linguistic errors found in the students' writings.Chapter eight, which is the final chapter, is devoted to a conclusion and implications for practice and future research

    Probucol Attenuates Oxidative Stress, Energy Starvation, and Nitric Acid Production Following Transient Forebrain Ischemia in the Rat Hippocampus

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    Oxidative stress and energy depletion are believed to participate in hippocampal neuronal damage after forebrain ischemia. This study has been initiated to investigate the potential neuroprotective effects of probucol, a lipid-lowering drug with strong antioxidant properties, against transient forebrain ischemia-induced neuronal damage and biochemical abnormalities in rat hippocampal CA1 region. Adult male Wistar albino rats were subjected to forebrain ischemia and injected with probucol for the next 7 successive days, and compared to controls. Forebrain ischemia resulted in a significant decrease in the number of intact neurons (77%), glutathione (GSH), and adenosine triphosphate (ATP), and a significant increase in thiobarbituric acid reactive substances (TBARS) and total nitrate/nitrite, (NOx) production in hippocampal tissues. The administration of probucol attenuated forebrain ischemia-induced neuronal damage, manifested as a complete reversal of the decrease in the number of intact neurons, ATP and GSH and the increase in TBARS and NOx in hippocampal tissues. This study demonstrates that probucol treatment abates forebrain ischemia-induced hippocampal neuronal loss, energy depletion, and oxidative stress in hippocampal CA1 region. Thus, probucol could be a promising neuroprotective agent in the treatment of forebrain ischemia

    Effect of Chloride Ions on the Corrosion Behavior of Al Zn Alloy in NaOH Solution at Four Different Temperatures

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    This research involves study effect of chloride ions in concentration range (0.01 0.50 mol.dm-3) on the corrosion behavior of Al-Zn alloy in basic media of 1x10-3 mol.dm-3 NaOH at pH=11 and four different temperatures in the range (298-313 K). Cathodic and anodic Tafel slopes (bc &ba) and transfer coefficients (αc & αa) were calculated and the results interprets according to the variation of the rate determining steps. The results also indicate that the chloride ions are bonded chemically in the interface as an initial step of formation of different mixed oxohydroxy and chloro complexes. Polarization resistance (Rp) is calculates and interprets the different polarization behavior because of addition of chloride ions to the basic media

    Dynamic Behavior of Jacket Type Offshore Structure

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    Unlike structures in the air, the vibration analysis of a submerged or floating structure such as offshore structures is possible only when the fluid-structures is understood, as the whole or part of the structure is in contact with water. Using the commercial F.E.A. program ANSYS (v.12.0) (to model the Winkler and Brick-full bond models) and program ABAQUS(v.6.9) (to model the Brickinterface model), the stress matrix considering a dynamic load was superposed on the stiffness matrix of the structure. A time domain solution is recommended, using the generalized Morison’s equation by FORTRAN90 program to construct a program to calculate the wave forces, and Airy's linear and Second Order Stoke's wave theories are employed to describe the flow characteristics by using MAPLE13 program (to solve and apply the boundary conditions of the problems on Laplace's equation), and the results are compared and discussed. Both free and forced vibration analyses are carried out for two case studies

    Medication prescribing errors in a pediatric inpatient tertiary care setting in Saudi Arabia

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    <p>Abstract</p> <p>Background</p> <p>Medication errors (MEs) are among the most common types of medical errors and one of the most common and preventable causes of iatrogenic injuries. The aims of the present study were; (i) to determine the incidence and types of medication prescribing errors (MPEs), and (ii) to identify some potential risk factors in a pediatric inpatient tertiary care setting in Saudi Arabia.</p> <p>Findings</p> <p>A five-week retrospective cohort study identified medication errors in the general pediatric ward and pediatric intensive care unit (PICU) at King Abdulaziz Medical City (KAMC) through the physical inspection of physician medication orders and reviews of patients' files. Out of the 2,380 orders examined, the overall error rate was 56 per 100 medication orders (95% CI: 54.2%, 57.8%). Dose errors were the most prevalent (22.1%). These were followed by route errors (12.0%), errors in clarity (11.4%) and frequency errors (5.4%). Other types of errors were incompatibility (1.9%), incorrect drug selection (1.7%) and duplicate therapy (1%). The majority of orders (81.8%) had one or more abbreviations. Error rates were highest in prescriptions for electrolytes (17.17%), antibiotics (13.72%) and bronchodilators (12.97%). Medication prescription errors occurred more frequently in males (64.5%), infants (44.5%) and for medications with an intravenous route of administration (50.2%). Approximately one third of the errors occurred in the PICU (33.9%).</p> <p>Conclusions</p> <p>The incidence of MPEs was significantly high. Large-scale prospective studies are recommended to determine the extent and outcome of medication errors in pediatric hospitals in Saudi Arabia.</p

    Re-sequencing of the APOAI promoter region and the genetic association of the -75G > A polymorphism with increased cholesterol and low density lipoprotein levels among a sample of the Kuwaiti population

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    BACKGROUND: APOAI, a member of the APOAI/CIII/IV/V gene cluster on chromosome 11q23-24, encodes a major protein component of HDL that has been associated with serum lipid levels. The aim of this study was to determine the genetic association of polymorphisms in the APOAI promoter region with plasma lipid levels in a cohort of healthy Kuwaiti volunteers. METHODS: A 435 bp region of the APOAI promoter was analyzed by re-sequencing in 549 Kuwaiti samples. DNA was extracted from blood taken from 549 healthy Kuwaiti volunteers who had fasted for the previous 12 h. Univariate and multivariate analysis was used to determine allele association with serum lipid levels. RESULTS: The target sequence included a partial segment of the promoter region, 5’UTR and exon 1 located between nucleotides −141 to +294 upstream of the APOAI gene on chromosome 11. No novel single nucleotide polymorphisms (SNPs) were observed. The sequences obtained were deposited with the NCBI GenBank with accession number [GenBank: JX438706]. The allelic frequencies for the three SNPs were as follows: APOAI rs670G = 0.807; rs5069C = 0.964; rs1799837G = 0.997 and found to be in HWE. A significant association (p < 0.05) was observed for the APOAI rs670 polymorphism with increased serum LDL-C. Multivariate analysis showed that APOAI rs670 was an independent predictive factor when controlling for age, sex and BMI for both LDL-C (OR: 1.66, p = 0.014) and TC (OR: 1.77, p = 0.006) levels. CONCLUSION: This study is the first to report sequence analysis of the APOAI promoter in an Arab population. The unexpected positive association found between the APOAI rs670 polymorphism and increased levels of LDL-C and TC may be due to linkage disequilibrium with other polymorphisms in candidate and neighboring genes known to be associated with lipid metabolism and transport

    Ionophore-based potentiometric PVC membrane sensors for determination of phenobarbitone in its pharmaceutical formulations

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    The fabrication and development of two polyvinyl chloride (PVC) membrane sensors for assaying phenobarbitone sodium are described. Sensors 1 and 2 were fabricated utilizing - or -cyclodextrin as ionophore in the presence of tridodecylmethylammonium chloride as a membrane additive, and PVC and dioctyl phthalate as plasticizer. The analytical parameters of both sensors were evaluated according to the IUPAC guidelines. The proposed sensors showed rapid, stable anionic response (–59.1 and –62.0 mV per decade) over a relatively wide phenobarbitone concentration range (5.0×10–6–1×10–2 and 8×10–6–1×10–2 mol L–1) in the pH range of 9–11. The limit of detection was 3.5×10–6 and 7.0×10–6 mol L–1 for sensors 1 and 2, respectively. The fabricated sensors showed high selectivity for phenobarbitone over the investigated foreign species. An average recovery of 2.54 µg mL–1 phenobarbitone sodium was 97.4 and 101.1 %, while the mean relative standard deviation was 3.0 and 2.1 %, for sensors 1 and 2, respectively. The results acquired for determination of phenobarbitone in its dosage forms utilizing the proposed sensors are in good agreement with those obtained by the British Pharmacopoeial method
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