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Showing papers by "King Saud University published in 2007"


Journal ArticleDOI
TL;DR: A shape retrieval method using triangle-area representation for nonrigid shapes with closed contours that is effective in capturing both local and global characteristics of a shape, invariant to translation, rotation, and scaling, and robust against noise and moderate amounts of occlusion.

278 citations


Journal ArticleDOI
TL;DR: The oxadiazole derivatives 4c, 4g, 4i and 4j produced good dose-dependent anti-inflammatory activity, particularly against the tested Gram-positive bacteria Bacillus subtilis and yeast-like pathogenic fungus Candida albicans.

253 citations


Journal ArticleDOI
TL;DR: The aim was to delineate the phenotype and determine the genetic defects in two consanguineous families with an early‐onset, recessive muscle and cardiac disorder.
Abstract: Objective: The giant protein titin is essential for striated muscle development, structure, and elasticity. All titin mutations reported to date cause late-onset, dominant disorders involving either skeletal muscle or the heart. Our aim was to delineate the phenotype and determine the genetic defects in two consanguineous families with an early-onset, recessive muscle and cardiac disorder. Methods: Clinical and myopathological reevaluation of the five affected children, positional cloning, immunofluorescence, and Western blot studies were performed. Results: All children presented with congenital muscle weakness and childhood-onset fatal dilated cardiomyopathy. Skeletal muscle biopsies showed minicores, centrally located nuclei, and/or dystrophic lesions. In each family, we identified a homozygous titin deletion in exons encoding the C-terminal M-line region. Both deletions cause a frameshift downstream of the titin kinase domain and protein truncation. Immunofluorescence confirmed that truncated titins lacking the C-terminal end were incorporated into sarcomeres. Calpain 3 was secondarily depleted. Interpretation: M-line titin homozygous truncations cause the first congenital and purely recessive titinopathy, and the first to involve both cardiac and skeletal muscle. These results expand the spectrum of early-onset myopathies and suggest that titin segments downstream of the kinase domain are dispensable for skeletal and cardiac muscle development, but are crucial for maintaining sarcomere integrity.

207 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of the radius of the cross-sectional corners (edges) on the strength of small scale square concrete column specimens confined with FRP composite laminates was investigated.
Abstract: This paper presents the experimental and analytical results of the study carried out to investigate the influence of the radius of the cross-sectional corners (edges) on the strength of small scale square concrete column specimens confined with FRP composite laminates. The experimental part of the study was achieved by testing 20 specimens under uniaxial compression. Depending on the selected radius of the edges, the section varied from square to circular. Intermediate radii were about 1/6, 1/4, and 1/3 of the side dimension. The sharpest square specimens had a corner radius of 5 mm to make composite application easier and to avoid a premature rupture of the composite. The results show that smoothening the edges of square cross-section plays a significant role in delaying the rupture of the FRP composite at these edges, and the efficiency of FRP confinement is directly related to the radius of the cross-section edges. A modified analytical model is presented to predict the strength of FRP-confined square as well as circular sections. The predicted results are found to be in excellent agreement with the measured ones.

202 citations


Journal Article
TL;DR: Hypertension is increasing in prevalence in KSA affecting more than one fourth of the adult Saudi population, and it is recommended aggressive management of hypertension as well as screening of adults for hypertension early to prevent its damaging consequences if left untreated.
Abstract: OBJECTIVES To determine the prevalence of hypertension among Saudis of both gender, between the ages of 30-70 years in rural as well as urban communities. This work is part of a major national study on Coronary Artery Disease in Saudis Study (CADISS). METHODS This is a community-based study conducted by examining subjects in the age group of 30-70 years of selected households during a 5-year period between 1995 and 2000 in Saudi Arabia. Data were obtained from history using a validated questionnaire, and examination including measurement of blood pressure. The data were analyzed to provide prevalence of hypertension. Logistic regression was used to develop a risk assessment model for prevalence of hypertension. RESULTS The total number of subjects included in the study was 17,230. The prevalence of hypertension was 26.1% in crude terms. For males, the prevalence of hypertension was 28.6%, while for females; the prevalence was significantly lower at 23.9% (p<0.001). The urban population showed significantly higher prevalence of hypertension of 27.9%, compared to rural population's prevalence of 22.4% (p<0.001). The prevalence of CAD among hypertensive patients was 8.2%, and 4.5% among normotensive subjects (p<0.001). Increasing weight showed significant increase in prevalence of hypertension in a linear relationship. CONCLUSIONS Hypertension is increasing in prevalence in KSA affecting more than one fourth of the adult Saudi population. We recommend aggressive management of hypertension as well as screening of adults for hypertension early to prevent its damaging consequences if left untreated. Public health awareness of simple measures, such as low salt diet, exercise, and avoiding obesity, to maintain normal arterial blood pressure need to be implemented by health care providers.

198 citations


Journal ArticleDOI
TL;DR: Monitoring of glycaemic control using HbA1c could have additional benefits of identifying diabetic patients who are at a greater risk of cardiovascular complications, as well as a good predictor of lipid profile.
Abstract: Impaired lipid metabolism resulting from uncontrolled hyperglycaemia has been implicated in cardiovascular complications in diabetes patients. The aim of this study was to examine the impact of glycaemic control on the lipid profile of diabetic patients. We also determined the ability of glycated haemoglobin (HbA1c) as an indirect marker of dyslipidaemia. A total of 1011 type 2 diabetic patients (males, 574; females, 437; mean age, 59.76 years) were included in this study. Venous blood samples were collected from all the subjects after at least 8 h fasting. The sera were analysed for HbA1c, fasting blood glucose (FBG), total cholesterol, triglycerides (TG), high-density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL). The levels of HbA1c, FBG and LDL did not differ significantly between males and females. Female patients showed significantly higher serum cholesterol and HDL but significantly lower TG levels as compared to males. There was a highly significant correlation between HbA1c and FBG. Both HbA1c and FBG exhibited direct correlations with cholesterol, TG and LDL and inverse correlation with HDL; the magnitude of significance for all these lipid parameters being greater with HbA1c than FBG. There was a linear relationship between HbA1c and dyslipidaemia. The levels of serum cholesterol and TG were significantly higher and of HDL significantly lower in patients with worse glycaemic control as compared to patients with good glycaemic control. The findings of this study clearly indicate that HbA1c is not only a useful biomarker of long-term glycaemic control but also a good predictor of lipid profile. Thus, monitoring of glycaemic control using HbA1c could have additional benefits of identifying diabetic patients who are at a greater risk of cardiovascular complications.

197 citations


Journal ArticleDOI
TL;DR: The results showed that pipe service age was an important factor that must not be ignored in some pipes such as cast iron, steel, cement-line ductile iron (CLDI), and cement-lined cast iron ( CLCI) pipes especially when the bulk decay is not significant relative to the wall decay.

195 citations


Journal ArticleDOI
TL;DR: This work is able to find closed-form results for systems with moderately general structures, under the assumption that the cost of an attack against any given component increases linearly in the amount of defensive investment in that component.

193 citations


Journal Article
TL;DR: There are significant variations in the prevalence of consanguinity between certain regions as well as between rural and urban settlements that should be taken into consideration in further studies.
Abstract: OBJECTIVES To report on the prevalence of consanguinity in each region of the Kingdom of Saudi Arabia including the variation in prevalence between urban and rural settlements. METHODS The study was conducted over 2 years (2004-2005). A cross-sectional sample determined by multistage random probability sampling of Saudi households from each of the 13 regions of the Kingdom. As part of survey questionnaire, the mother of each household was asked on the relationship to her husband to choose one of 3 answers: first-degree cousin, more distant relationship, or no relation. RESULTS The overall prevalence of consanguinity was 56% with the first-degree cousin (33.6%) being more common than all other relations (22.4%). The overall prevalence was significantly more common in rural (59.5%) than in urban settlements (54.7%) (p=0.000). There are regions with high prevalence of 67.2% such as Madina, and regions with significantly lower prevalence of 42.1% such as Al-Baha (p=0.000). CONCLUSIONS The national prevalence of consanguinity in the Kingdom of Saudi Arabia remains high. In addition, there are significant variations in the prevalence of consanguinity between certain regions as well as between rural and urban settlements that should be taken into consideration in further studies.

176 citations


Journal ArticleDOI
TL;DR: The concept of sustainability has become central not just in housing policy, but also in the consideration of human settlements, employment, infrastructure, transportation and urban services as mentioned in this paper, and the concept has become one of the most overused and misunderstood urban policy component in use today.

162 citations


Journal ArticleDOI
TL;DR: The data suggest that the prevalence of physical inactivity among Saudis adults is relatively high and efforts are needed to encourage Saudis to be more physically active, with the goal of increasing the proportion of Saudis engaging in health-enhancing physical activity.
Abstract: Objectives: To describe the physical activity profile of Saudi adults living in Riyadh, using the International Physical Activity Questionnaire (IPAQ) short-version telephone format. Methods: Physical activity was assessed using the official Arabic short form of IPAQ, intended for use in telephone interview. The instrument asks for times spent in walking, moderate- and vigorous-intensity physical activity of at least 10min duration. The sample consisted of 1616 Saudis, between 15 and 78 years of age, living in Riyadh. Participants were drawn from a list of names in the telephone book using a simple random method. Telephone interviews were administered during the spring of 2003 by trained male interviewers. Results: The final sample size was 1064 Saudi males and females (response rate of 66%), with males comprising about 66% of the respondents. Over 43% of Saudis did not participate in any type of moderate-intensity physical activity lasting for at least 10min. More than 72% of the sample did not engage in any type of vigorous-intensity physical activity lasting for at least 10min. The proportion of Saudis who walked for 150min or more per week was 33.3%. Females were engaged more in moderate physical activity than males, whereas males participated more in vigorous activity compared with females. Activity levels did not show significant relationships with education level or job hours per week. Based on the three activity categories established by IPAQ, 40.6% of Saudis were inactive, 34.3% were minimally active and 25.1% were physically active. Physical inactivity increased with advancing age. Conclusion: The data suggest that the prevalence of physical inactivity among Saudis adults is relatively high. Efforts are needed to encourage Saudis to be more physically active, with the goal of increasing the proportion of Saudis engaging in healthenhancing physical activity.

Journal ArticleDOI
TL;DR: Sella shape and dimensions reported in the current study can be used as reference standards for further investigations involving the sella turcica area in Saudi subjects.
Abstract: The purpose of this study was to describe the shape and measure the size of the sella turcica in Saudi subjects with different skeletal types. Lateral cephalometric radiographs of 180 individuals (90 males and 90 females) with an age range of 11-26 years were taken and distributed according to skeletal classification; 60 Class I, 60 Class II, and 60 Class III. The sella turcica on each radiograph was analysed and measured to determine the shape of the sella, in addition to the linear dimensions of length, depth, and diameter. A Student's t-test was used to calculate differences in linear dimensions, while a one-way analysis of variance was performed to study the relationship between skeletal type and sella size. The results show that the sella turcica presented with a normal morphology in the majority of subjects (67 per cent). No significant differences in linear dimensions between genders could be found. When age was evaluated, significant differences were found between the older (15 years or more) and the younger (11-14 years) age groups at the 0.01 and 0.001 levels for length, depth, and diameter. Sella size of the older age group was larger than in the younger age group. When skeletal type was compared with sella size, a significant difference was found in the diameter of sella between the Class II and Class III subjects (P < 0.01). Larger diameter values were present in the skeletal Class III subjects, while smaller diameter sizes were apparent in Class II subjects (multiple comparison tests). When gender, age, and skeletal type were all compared with the size of the sella (regression analyses), age was significantly related to a change of length (P < 0.01) and diameter (P < 0.001). Sella shape and dimensions reported in the current study can be used as reference standards for further investigations involving the sella turcica area in Saudi subjects.

Journal ArticleDOI
TL;DR: ProTaper and K3 were found to be effective and faster in removing gutta-percha in comparison with hand Hedstrom files.

Journal ArticleDOI
TL;DR: Data from the present study suggest that TQ supplementation prevents the development of GM‐induced acute renal failure by a mechanism related to its ability to decrease oxidative stress and to preserve the activity of the anti‐oxidant enzymes, as well as it ability to prevent the energy decline in kidney tissues.
Abstract: SUMMARY 1. The present study investigated the possible protective effects of thymoquinone (TQ), a compound derived from Nigella sativa with strong anti-oxidant properties, against gentamicin (GM)-induced nephrotoxicity. 2. A total of 40 adult male Wistar albino rats was divided into four groups. Rats in the first group were injected daily with normal saline (2.5 mL/kg, i.p.) for 8 consecutive days, whereas rats in the second group received TQ (50 mg/L in drinking water) for 8 consecutive days. Animals in the third group were injected daily with GM (80 mg/kg, i.p.) for 8 consecutive days, whereas animals in the fourth group received a combination of GM (80 mg/kg, i.p.) and TQ (50 mg/L in drinking water) for 8 consecutive days. 3. Gentamicin resulted in a significant increase in serum creatinine, blood urea nitrogen (BUN), thiobarbituric acidreactive substances (TBARS) and total nitrate/nitrite (NOx) and a significant decrease in reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT) and ATP levels in kidney tissues. 4. Interestingly, TQ supplementation resulted in a complete reversal of the GM-induced increase in BUN, creatinine, TBARS and NOx and decrease in GSH, GPx, CAT and ATP to control values. Moreover, histopathological examination of kidney tissues confirmed the biochemical data, wherein TQ supplementation prevents GM-induced degenerative changes in kidney tissues. 5. Data from the present study suggest that TQ supplementation prevents the development of GM-induced acute renal failure by a mechanism related, at least in part, to its ability to decrease oxidative stress and to preserve the activity of the anti-oxidant enzymes, as well as it ability to prevent the energy decline in kidney tissues.

Journal ArticleDOI
TL;DR: In this paper, equal channel angle pressing (ECAP) of commercial purity aluminum (1050) was conducted using two processing routes, namely routes BC and C, up to eight passes.
Abstract: Equal channel angle pressing (ECAP) of commercial purity aluminum (1050) was conducted using two processing routes, namely routes BC and C. The variation of hardness and yield strength with number of pressings was documented up to eight passes. Compression tests were used to evaluate post ECAP deformation response. Electron back scattered diffraction (EBSD) was used to obtain statistical information on the microstructure developed (cell size and misorientation angle) during ECAP and after combining ECAP with simple compression. The present results showed that first ECAP pass has resulted in enhancement of mechanical properties more than three times over the annealed condition. Further ECAP processing has resulted in slight improvement. The true stress–strain curve for ECAPed specimens tested under compression showed short transient region of large strain hardening rate followed by perfectly plastic behavior and strain softening. This behavior was discussed in details based on the microstructure study. © 2006 Elsevier B.V. All rights reserved.

Journal ArticleDOI
TL;DR: In this article, the authors used the S-wave receiver function technique to produce the first images of the lithosphere-asthenosphere boundary (LAB) structure along the Red Sea and throughout the Arabian Peninsula.

Journal ArticleDOI
TL;DR: A 63-kb intragenic LARGE deletion in a family with Walker-Warburg syndrome (WWS), which is characterized by CMD, and severe structural brain and eye malformations, demonstrates that LARGE gene mutations can give rise to a wide clinical spectrum, similar to other genes that have a role in the post-translational modification of the α-dystroglycan protein.
Abstract: Intragenic homozygous deletions in the Large gene are associated with a severe neuromuscular phenotype in the myodystrophy (myd) mouse These mutations result in a virtual lack of glycosylation of alpha-dystroglycan Compound heterozygous LARGE mutations have been reported in a single human patient, manifesting with mild congenital muscular dystrophy (CMD) and severe mental retardation These mutations are likely to retain some residual LARGE glycosyltransferase activity as indicated by residual alpha-dystroglycan glycosylation in patient cells We hypothesized that more severe LARGE mutations are associated with a more severe CMD phenotype in humans Here we report a 63-kb intragenic LARGE deletion in a family with Walker-Warburg syndrome (WWS), which is characterized by CMD, and severe structural brain and eye malformations This finding demonstrates that LARGE gene mutations can give rise to a wide clinical spectrum, similar as for other genes that have a role in the post-translational modification of the alpha-dystroglycan protein

Journal ArticleDOI
TL;DR: Untreated sinusitis and prior history of orbital trauma were the 2 major causes of orbital cellulitis in patients referred to a tertiary care eye center in the Middle East.

Journal ArticleDOI
TL;DR: In this article, the authors examine some long-standing assumptions about the early use of coastlines and marine resources and their contribution to the pattern of early human dispersal, focusing on the southern Red Sea Basin and the proposed southern corridor of movement between Africa and Arabia across the Bab al-Mandab Straits.
Abstract: We examine some long-standing assumptions about the early use of coastlines and marine resources and their contribution to the pattern of early human dispersal, and focus on the southern Red Sea Basin and the proposed southern corridor of movement between Africa and Arabia across the Bab al-Mandab Straits. We reconstruct relative sea levels in light of isostatic and tectonic effects, and evaluate their paleogeographical impact on the distribution of resources and human movement. We conclude that the crossing of the Bab al-Mandab posed little significant or long-lasting physical or climatic barrier to human transit during the Pleistocene and that the emerged continental shelf during periods of low sea level enhanced the possibilities for human settlement and dispersal around the coastlines of the Arabian Peninsula. We emphasize the paleogeographical and paleoenvironmental significance of Pleistocene sea-level change and its relationship with changes in paleoclimate, and identify the exploration of...

Journal ArticleDOI
TL;DR: In this paper, trilathin films of highly monodispersed luminescent Si nanoparticles are directly integrated on polycrystalline Si solar cells, and the authors monitor the open-circuit voltage and short circuit current.
Abstract: Ultrathin films of highly monodispersed luminescent Si nanoparticles are directly integrated on polycrystalline Si solar cells. The authors monitor the open-circuit voltage and the short circuit current. The results demonstrate that films of 1 nm blue luminescent or 2.85 nm red luminescent Si nanoparticles produce large voltage enhancements with improved power performance of 60% in the UV/blue range. In the visible, the enhancements are ∼ 10 % for the red and ∼ 3 % for the blue particles. The results point to a significant role for charge resonant transport across the nanofilm and Schottky-like rectification at nanoparticle-metal interface.

Journal ArticleDOI
TL;DR: The results clearly demonstrated the ability of the system to maintain tight blood glucose level and improved the patient compliance by enhancing, controlling and prolonging the systemic absorption of gliclazide.

Journal ArticleDOI
Suhil Kiwan1
TL;DR: In this article, the effect of different design and operating parameters such as: Ra number, Da number, thermal conductivity ratio, Kr and length thickness ratio on the temperature distribution along the fin is grouped into one newly defined parameter called S_H.
Abstract: This work introduces a simple method of analysis to study the performance of porous fins in a natural convection environment. The method is based on using energy balance and Darcy’s model to formulate the heat transfer equation. The thermal performance of porous fins is then studied for three types of fins: long fin, finite-length fin with insulated tip and a finite-length fin with tip exposed to a known convection coefficient. It is found from the analysis that the effect of different design and operating parameters such as: Ra number, Da number, thermal conductivity ratio, Kr and length thickness ratio on the temperature distribution along the fin is grouped into one newly defined parameter called S_H. The effect of the variation of S_H on the porous fin thermal performance is established. The effect of varying the fin length and thermal conductivity ratio on the heat transfer rate from the fin is investigated and compared with that for a solid fin at certain conditions. It is found that the heat transfer rate from porous fin could exceed that of a solid fin. It is also found that increasing the fin length and effective thermal conductivity enhances the heat transfer from the fin up certain limit, where a further increase in these parameters adds no improvement to the fin performance.

Journal ArticleDOI
TL;DR: It is demonstrated that Tdp1 repairs Topo I covalent lesions in vivo and suggests that SCAN1 arises from the recessive neomorphic mutation H493R, a novel mechanism for disease since neomorphic mutations are generally dominant.
Abstract: Tyrosyl-DNA phosphodiesterase 1 (Tdp1) cleaves the phosphodiester bond between a covalently stalled topoisomerase I (Topo I) and the 3′ end of DNA. Stalling of Topo I at DNA strand breaks is induced by endogenous DNA damage and the Topo I-specific anticancer drug camptothecin (CPT). The H493R mutation of Tdp1 causes the neurodegenerative disorder spinocerebellar ataxia with axonal neuropathy (SCAN1). Contrary to the hypothesis that SCAN1 arises from catalytically inactive Tdp1, Tdp1−/− mice are indistinguishable from wild-type mice, physically, histologically, behaviorally, and electrophysiologically. However, compared to wild-type mice, Tdp1−/− mice are hypersensitive to CPT and bleomycin but not to etoposide. Consistent with earlier in vitro studies, we show that the H493R Tdp1 mutant protein retains residual activity and becomes covalently trapped on the DNA after CPT treatment of SCAN1 cells. This result provides a direct demonstration that Tdp1 repairs Topo I covalent lesions in vivo and suggests that SCAN1 arises from the recessive neomorphic mutation H493R. This is a novel mechanism for disease since neomorphic mutations are generally dominant.

Journal ArticleDOI
TL;DR: In this paper, acid anhydrides, imides and dicarboxylic acids were successfully subjected to dehydrative cyclization with substituted amines using DPPOx and Et(3)N to afford N-substituted imides under mild conditions.

Journal ArticleDOI
TL;DR: In this paper, the behavior of concrete cylinders with varying compressive strength wrapped with E-glass/epoxy fiber reinforced polymer (GFRP) jackets and subjected to uniaxial compressive loads was investigated.
Abstract: This paper is aimed at studying the behavior of concrete cylinders with varying compressive strength wrapped with E-glass/epoxy fiber reinforced polymer (GFRP) jackets and subjected to uniaxial compressive loads. A comprehensive experimental program which involves 54 plain concrete cylinders was conducted in this study. The cylinders evaluated in this study, were divided into six groups, and each group contain a control cylinder without confinement to quantify the amount of gain obtained using the GFRP laminates. Experimental results indicated that the use of GFRP jackets substantially increases both the compressive strength and ductility of unreinforced concrete cylinders. In this paper, the influences of two parameters influencing the behavior of the GFRP confined cylinder is investigated. These parameters are: the number of composite plies (i.e. composite thickness) and concrete compressive strength. The results of this study showed that: (i) compressive strength and ductility of the concrete cylinders increases with number of composite layers; and (ii) effect of confinement is substantial for normal strength concrete and marginal for high-strength concrete. A semi-empirical theoretical model is also presented in order to predict stress–strain relationship of GFRP confined concrete cylinders. The model results showed an excellent agreement with experimental values.

Journal ArticleDOI
TL;DR: The problems of maintaining oral care with oral intubation, performing oral assessment, guidelines for oral hygiene care, frequency of oral care needed, and suggested mouth care protocol followed by recommendations are presented and discussed in this paper.
Abstract: Oral care for patients in the hospital's Intensive Care Unit (ICU) is important, but this is usually the responsibility of nurses without sufficient knowledge in oral care or comprehensive protocols to follow. The problems of maintaining oral care with oral intubation, performing oral assessment, guidelines for oral hygiene care, frequency of oral care needed, and suggested mouth care protocol followed by recommendations are presented and discussed in this paper.

01 Jan 2007
TL;DR: A new model for predicting the impure and pure CO2–oil MMP and the effects of impurities on MMP is presented, which yielded the accurate prediction of the experimental slim-tube CO2- oil MMP with the lowest average relative and average absolute error.
Abstract: CO2 injection processes are among the effective methods for enhanced oil recovery A key parameter in the design of CO2 injection project is the minimum miscibility pressure (MMP), whereas local displacement efficiency from CO2 injection is highly dependent on the MMP From an experimental point of view, slim tube displacements, and rising bubble apparatus (RBA) tests routinely determine the MMP Because such experiments are very expensive and time-consuming, searching for fast and robust mathematical determination of CO2–oil MMP is usually requested It is well recognized that CO2–oil MMP depends upon the purity of CO2, oil composition, and reservoir temperature This paper presents a new model for predicting the impure and pure CO2–oil MMP and the effects of impurities on MMP The alternating conditional expectation (ACE) algorithm was used to estimate the optimal transformation that maximizes the correlation between the transformed dependent variable (CO2–oil MMP) and the sum of the transformed independent variables These independent variables are reservoir temperature (TR), oil compositions (mole percentage of volatile components (C1 and N2), mole percentage of intermediate components (C2–C4, H2S and CO2), and molecular weight of C5+ (MWC5+)), and non-CO2 components (mole percentage of N2, C1, C2–C4, and H2S) in the injected CO2 The validity of this new model was successfully approved by comparing the model results to the pure and impure experimental slim-tube CO2–oil MMP and the calculated results for the common pure and impure CO2–oil MMP correlations The new model yielded the accurate prediction of the experimental slim-tube CO2–oil MMP with the lowest average relative and average absolute error among all tested impure and pure CO2–oil MMP correlations In addition, the new model could be used for predicting the impure CO2–oil MMP at higher fractions of non-CO2 components

Journal ArticleDOI
TL;DR: In this article, empirical models for tool life, surface roughness and cutting force are developed for turning operations for turning austenitic AISI 302 and 28 experiments were used to generate, compare and evaluate the proposed models.

Journal ArticleDOI
TL;DR: TQ is effective in protecting rats against l‐NAME‐induced hypertension and renal damage possibly via antioxidant activity, and inhibited the in vitro production of superoxide radical in enzymatic and non‐enzymatic systems.
Abstract: The present study was undertaken to evaluate the protective effect of thymoquinone (TQ), the main constituent of the volatile oil from Nigella sativa seeds, in rats after chronic inhibition of nitric oxide synthesis with N(omega)-nitro-l-arginine methyl esters (l-NAME) Rats were divided randomly into different treatment groups: control, l-NAME, TQ and l-NAME + TQ Hypertension was induced by 4 weeks administration of l-NAME (50 mg/kg/day po) TQ was administered alone or in combination with l-NAME and continued for 4 weeks The animals were killed, and the serum and kidney tissues were isolated for the determination of creatinine and glutathione (GSH), respectively Rats receiving l-NAME showed a progressive increase in systolic blood pressure compared with control rats Concomitant treatment with TQ (05 and 1 mg/kg/day po) reduced the increase in systolic blood pressure induced by l-NAME in a dose dependent manner Kidney injury was demonstrated by a significant increase in serum creatinine and a decrease in GSH in kidney tissue from l-NAME treated rats Treatment of rats with TQ decreased the elevated creatinine and increased GSH to normal levels TQ inhibited the in vitro production of superoxide radical in enzymatic and non-enzymatic systems In conclusion, TQ is effective in protecting rats against l-NAME-induced hypertension and renal damage possibly via antioxidant activity

Journal ArticleDOI
TL;DR: The objectives of the present study were to test the in vivo effect of peripherally administered ghrelin on gastric I/R‐induced lesions in rats and investigate in vitro the effect of gh Relin on reactive oxygen species (ROS) production by human polymorphoneuclear (PMN) cells.
Abstract: Background and Aim: Gherlin, an endogenous ligand for the growth hormone secreta- gogue receptor (GHS-R), is produced by stomach cells. It regulates food intake, gastric secretion and motility. However, its role as a protective agent in gastric ischemia/ reperfusion (I/R) injury has not yet been investigated. Therefore, the objectives of the present study were to: (i) test the in vivo effect of peripherally administered ghrelin on gastric I/R-induced lesions in rats; and (ii) investigate in vitro the effect of ghrelin on reactive oxygen species (ROS) production by human polymorphoneuclear (PMN) cells. Methods: The present study was carried out on three groups of rats (six per group): control (sham-operated), I/R (clamping of celiac artery for 30 min and reperfusion for 1 h), and I/R + ghrelin (200 ng/kg i.v., 15 min before ischemia and before reperfusion, respectively). Histological assessment of hematoxylin and eosin stained sections was performed and immunostaining with inducible nitric oxide (iNOS) antibody were performed on a gastric paraffin embedded section. Oxidative stress markers thiobarbituric acid reactive substance (TBARS) and glutathione (GSH) were measured in gastric tissue homogenates. Serum lactic acid dehydrogenase (LDH) was determined. Tumor necrosis factor-alpha (TNF-a) was assayed in gastric tissue homogenate. Gastric permeability was assessed calorimetri- cally using Evans blue dye. In vitro studies were carried out on isolated human PMN cells incubated with ghrelin and tested for ROS generation as measured by chemiluminecence (CL). Results: Peripheral administration of ghrelin attenuated gastric injury by reducing ulcer- ation, tissue congestion, cellular infiltration and vascular permeability. Serum level of LDH and tissue content of TNF-a were markedly reduced. A decrement in TBARS and an increment in GSH were observed. Ghrelin treatment attenuated iNOS protein expression which was upregulated by gastric ischemic injury. In vitro studies showed for the first time that ghrelin inhibited ROS generation by human PMN in a dose-dependent manner. Conclusions: These results provide evidence that peripherally administered ghrelin pro- tects against gastric I/R injury. We also demonstrated that this protection is possibly accomplished through the antioxidant activity of ghrelin observed in vivo and in vitro.