Riyadh, Saudi Arabia
Riyadh, Saudi Arabia

King Saud University is a public university located in Riyadh, Saudi Arabia. It was founded in 1957 by King Saud bin Abdul Aziz as Riyadh University, as the first university in the kingdom not dedicated to religious subjects. The university was created to meet the shortage of skilled workers in Saudi Arabia. It was renamed to King Saud University in 1982. The student body of KSU today consists of about 37,874 students of both sexes. Wikipedia.

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King Saud University | Date: 2015-09-30

The synthetic recycled plastic aggregate for use in concrete is a composite material containing between 30% and 50% by weight shredded recycled plastic, the balance being a filler embedded in a matrix of the recycled plastic. The recycled plastic includes polyethylene terephthalate (PET). The filler can include dune sand, fly ash and quarry fines. The synthetic recycled plastic aggregate is best used to make concrete with a water-to-cement ratio of at least 0.5.

King Saud University | Date: 2015-09-29

Novel -Glucosidase inhibitors include propanone substituted indole ring-containing heterocyclic compounds, which are represented by Formula I: Wherein

The method of ascertaining fully grown passive film formation on steel rebar embedded in concrete utilizes electrochemical impedance spectroscopy (EIS) to determine, in situ, the degree of passive film formation on steel rebar embedded in concrete. A length of steel rebar and a counter electrode are both embedded in a concrete slab. A reservoir is supported on an external face of the concrete slab and filled with an electrolytic solution. A reference electrode is then positioned in the electrolytic solution, and the length of steel rebar, the counter electrode and the reference electrode are electrically connected an EIS test instrument to perform electrochemical impedance spectroscopy. The quality of passive film formation on the length of steel rebar is determined based on comparison of the electrochemical impedance spectroscopy results with known passive film formation data.

King Saud University | Date: 2015-07-28

The spectral method for quantifying hemoglobin fragility caused by smoking is based on decreased concentration of tryptophan and elevated concentrations of the biomolecules nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), and porphyrin in the presence of hemoglobin fragility. The method involves the steps of obtaining a blood sample from a patient who is a smoker; separating blood plasma from the samples; obtaining synchronous excitation spectra (SXS) of the blood plasma with a spectrofluorometer at a scan offset of 70 nm and at a scan offset of 10 nm; comparing the patients SXS with the SXS of normal control samples; and diagnosing hemoglobin fragility when the excitation maxima of NADH, FAD, and porphyrin are between 30% and 70% higher than the maxima for these metabolites in the normal control samples, or when the excitation maximum for tryptophan is 60% of the control sample.

Background: Gold nanoparticle (GNP) levels in the blood of rats in vivo have not been previously documented. This study aimed to evaluate the influence of size and exposure duration of GNPs on the gold levels in the blood of rats in vivo. Methods: Thirty rats were divided into five groups, NG = control group, G1A: infusion of 10 nm GNPs for three days, G1B: 10 nm GNPs for seven days, G2A: 50 nm GNPs for three days and G2B: 50 nm GNPs for seven days. Fifty microlitres of GNPs dissolved in aqueous solution were administered intraperitoneally every day for three and seven days. Gold concentrations in different samples were measured using inductively coupled plasma-optical emission spectrometer (ICP-OES). Results: The percentage normalized value of 50nm GNPs increased in the blood of rats in both three and seven days when compared with 10 nm GNPs. Conclusions: It became evident from the results of this study that the alterations in GNP levels were Size dependent, with the smaller ones inducing the most toxic effects and related to the time exposure of GNPs. The results might indicate that the smaller GNPs are mostly taken up and accumulate in the different rat organs, suggesting their toxic effects, while the 50 nm GNPs are retained in the blood of rats for a long time. These conclusions are further supported by the histological investigation.

Alashaikh A.H.,King Saud University
Arabian Journal of Geosciences | Year: 2017

In general, spatial data are not unified in the same coordinate system. The combination of data from different sources is considered a problematic practice in land surveying and geographic information systems (GIS). Therefore, there is a need to apply one of the coordinate transformation methods, in which have two types of transformations: analytical and numerical. The Universal Transverse Mercator (UTM) projection is widely used for maps in the Kingdom of Saudi Arabia (KSA), along with two different data: The World Geodetic System 1984 (WGS84) and The National Geodetic Network (NGN). This makes the process of analytical transformation more complex. In this paper, a new numerical transformation technique using a second-degree polynomial is proposed. Both analytical and numerical (second-degree polynomial) transformation types were applied for a single group of study points. Coordinates obtained from both the methods were compared. Moreover, the proposed method was also verified against the conformity criterion. Results indicated that the proposed transformation technique is conformal and can be effectively used for KSA maps. © 2017, Saudi Society for Geosciences.

Al-Numay M.S.,King Saud University
Journal of Computational and Theoretical Nanoscience | Year: 2016

Nanoelectronics are the backbone of several existing and developing technologies such as high-end military equipment, space ships, home appliances, automobiles and so on. Nanoelectronics can improve the performance and reduce the size and cost of DC-DC switched converters. The discrete-time output tracking control of pulse-width modulated (PWM) DC-DC switched converters is a challenging task in the nanoelectronics due to the existence of unacceptable zeros (such as unstable zeros) and nonlinear dynamics. Therefore, in this paper the output redefinition method is developed in the discrete time domain to overcome the instability of the system due to the presence of unacceptable zero. The proposed approach is presented for three different output tracking objectives: namely, Zero DC Error Tracking Controller (ZDCETC), Zero Phase Error Tracking Controller (ZPETC), and Zero Magnitude Error Tracking Controller (ZMETC) in a unified way. The proposed output tracking method is further enhanced to reduce the error and increase the accuracy, while maintaining the system stability, by developing the scheduled output redefinition operating points. The effectiveness of the proposed three stable approximate output tracking control options is evaluated and verified to track a desired output signal. The numerical simulation results confirm bounded and non-oscillatory responses with minimal tracking errors. Copyright © 2016 American Scientific Publishers All rights reserved.

Alodhayani A.A.,King Saud University
Biomedical Research (India) | Year: 2017

The services available in the home for the elderly patients suffering from the injured or diseases are defined as Home Health Care (HHC). This service is more convenient and less expensive to the elder population. Most of the subjects who were>65 years are not supportive towards the hospital based services. However, in the hospital care, the complete information of the care taken towards the patients will be documented. Therefore, the main concept of this literature was to compare between HHC services with the hospital care services for the coziness in the elderly population. The elder population in Saudi Arabia has been increasing rapidly and there are no special, private or personal services. Only the hospital based services are provided for care taking in elder population. This review recommends the HHC services in the Saudi Arabia region in both the private and non-private sector (government/ public). © 2017, Scientific Publishers of India. All rights reserved.

The field of family medicine is emerging as a cornerstone for the providing comprehensive, quality care to a diverse population. The importance of family medicine in Saudi Arabia has also rapidly increased due to the growing morbidity and mortality for preventable diseases. Therefore, it is necessary to train qualified and competent family medicine practitioners, and their scarcity in Saudi Arabia should be addressed on a priority basis. The objective of this study is to assess the knowledge of Saudi medical students about the family medicine specialty and their attitude towards selecting family medicine as a career. A quantitative method is used to assess the knowledge and attitudes of fourth year medical students training in a family medicine clinical course in King Saud University as part of their curriculum during (March 2015-May 2015). The study participants were evaluated through questionnaire-based responses before and after commencing their clinical rotation training. The study findings deduced that the family medicine clinical course has a significant effect on medical students' career decisions, and this course is beneficial in improving students’ knowledge of family medicine (P=0.009). The study responses suggested that students become more determined to practice family medicine after completing their clinical training (P=0.034). Many of the study participants have chosen family medicine as a career after acquiring extensive knowledge on the subject (58%). Approximately 81% of the participants believe that it is an integral part of the healthcare system in Saudi Arabia. The top reasons why students included family medicine in their career plans were observations of the physician-patient interaction in this specialty (66.7%); the faculty staff’s attitudes, interests and compassion (61.5%); and the enjoyment of the family medicine rotation (51.3%). Based on the study findings that the family medicine clinical rotation was highly beneficial for medical students in terms of improving their knowledge about and attitude toward the field, the choice of family medicine as a career was not affected by the course. Instead, the student’s personal perception and passion to pursue family medicine as a practice influences the student’s career choice. © 2017, Scientific Publishers of India. All rights reserved.

Ahsanullah T.M.G.,King Saud University | Jager G.,Stralsund University of Applied Sciences
Fuzzy Sets and Systems | Year: 2017

If L and M are frames, and N is a quantale, then using stratification mappings between frames, we introduce a category of stratified LMN-convergence tower groups - a topological category. We then prove that every stratified LMN-limit tower group induces a stratified LMN-uniform convergence tower space. Also, we introduce a category of stratified LMN-Cauchy tower groups, and show that the category of strongly normal stratified LMN-limit tower groups, is isomorphic to the category of stratified LMN-Cauchy tower groups. We provide various examples in support of our theories so far developed herein the text. © 2017 Elsevier B.V.

Alhussein M.,King Saud University
Proceedings - 2016 UKSim-AMSS 18th International Conference on Computer Modelling and Simulation, UKSim 2016 | Year: 2016

This paper proposed a new image tampering detection method based on local texture descriptor and extreme learning machine (ELM). The image tampering includes both splicing and copy-move forgery. First, the image was decomposed into three color channels (one luminance and two Chroma), and each channel was divided into non-overlapping blocks. Local textures in the form of local binary pattern (LBP) were extracted from each block. The histograms of the patterns of all the blocks were concatenated to form a feature vector. The feature vector was then fed to an ELM for classification. The ELM is a powerful and fast classification approach. The experiments was performed using two publicly available databases. The experimental results showed that the proposed method achieved a high detection accuracy in both the databases. © 2016 IEEE.

Highly luminescent and aqueous soluble CeF3:Tb (core),CeF3:Tb@LaF3(core/shell) and CeF3:Tb@LaF3@ SiO2 (core/shell/Si) nanoparticles(NPs) with mean particle size 12 nm were prepared by co-precipitation method at low temperature. X-ray diffraction pattern verified the phase purity, high crystallinity of hexagonal structure. The TEM image and SAED pattern revealed the single phase polycrystalline nature, well-dispersed irregular shaped hexagonal structure. FTIR spectra show the characteristic infrared peaks of silica, it suggests the successful silica surface coating around the core/shell NPs. The excitation and emission intensity of core/shell NPs were remarkably increased then their counterpart core NPs. It implies that a significant amount of nonradiative transition centers existing on the surface of core NPs has been eliminated due to the formation of passivated LaF3 layer. The silica surface modification over the core/shell NPs strikingly enhanced the solubility character in an aqueous environment. © 2017 Elsevier B.V.

Mahmood A.,King Saud University
Tetrahedron | Year: 2017

From what began as a casual discovery of the ketene-Claisen rearrangement (the Malherbe-Belluš rearrangement) over 3 decades ago has flourished a reaction of substantial significance. The noticeable qualities of the ketene-Claisen rearrangement is accomplished in terms of experimental simplicity, forming new C[sbnd]C bonds, high levels of chemo- and stereocontrol, ring enlargements and constructing new stereocenters. This survey of the ketene-Claisen rearrangement with some applications in organic synthesis will not only recapitulate the prospective of this reaction so far but also illustrate the achievable future significant prospective. © 2017 Elsevier Ltd

Bin-Omran S.,King Saud University
Materials Letters | Year: 2017

The first-principles-derived approach combined with the Wang-Landau algorithm is used to precisely determine the thickness dependence of the ferroelectric and electrocaloric (EC) effect response in stress-free (Ba0.50Sr0.50)TiO3 thin films under ideal short-circuit electrical boundary conditions. The results indicate that as the film's thickness decreases, the polarization, transition temperature, and diffuseness character of the phase transition are enhanced, while the maximum value of the specific heat occurring near the transition temperature increases when the film thickness increases. The calculations also reveal that the EC strength described by ΔT/Δε in the thinnest-studied BST films increases when decreasing the thickness of the films, while this response decreases as the film's thickness decreases in the thickest-investigated BST film. At room temperature, the calculated values of the EC response for BST films are higher than values measured for BTO films. © 2017 Elsevier B.V.

Ebaid Y.Y.,Fayoum University | Khater A.E.M.,King Saud University
Journal of Environmental Radioactivity | Year: 2017

In this study the commonly used f-value for the 1001.03 keV (0.835 ± 0.004%) energy transition of the 234mPa was re-evaluated due to an obvious consistent overestimation of the 238U activity concentration. Different calibration protocols, samples’ matrices and geometries, and gamma-ray spectrometers were exploited in order to assure the accuracy of the derived data. An average positive relative bias of about 24% from the currently used f-value was estimating leading to newly adopted f-value of 1.037 ± 0.052%. This newly suggested f-value will lead to an improvement in the accurate assessment process of the 238U using gamma-ray spectrometry in both environmental and nuclear safeguard fields. © 2017 Elsevier Ltd

Al-Wabli R.I.,King Saud University
Profiles of Drug Substances, Excipients and Related Methodology | Year: 2017

Lomefloxacin is a second-generation difluorinated broad-spectrum quinolone antibiotic. It is used for the treatment of bronchitis, urinary tract infection, conjunctivitis, otitis externa, and otitis media. A comprehensive profile was performed on lomefloxacin including nomenclature, formulae, elemental composition appearance, and physical characteristics. Spectral methods including ultraviolet spectrum, vibrational spectrum, 1H and 13C nuclear magnetic resonance one- and two-dimensional spectra, and mass spectrum were used for both identification and analysis of the drug. The profile also contains the reported methods of analysis such as voltammetric, polarographic, spectrophotometric, fluorimetric, chromatographic, capillary electrophoresis, and immunoassay methods. In addition, the uses, pharmacokinetics, and chemical synthesis of lomefloxacin are described. © 2017 Elsevier Inc.

Almadani S.,King Saud University
Journal of Seismology | Year: 2017

On the 27 June 2015, at 15:34:03 UTC, a moderate-sized earthquake of Mw 5.0 occurred in the Gulf of Aqaba. Using teleseismic P waves, the focal mechanism of the mainshock was investigated by two techniques. The first technique used the polarities of the first P wave onsets, and the second technique was based on the normalized waveform modeling technique. The results showed that the extension stress has a NE orientation with a shallow southward plunge while the compression stress has a NW trend with a nearly shallow westward plunge, obtaining a strike-slip mechanism. This result agrees well with the typical consequence of crustal deformation resulting from the ongoing extensional to shear stress regime in the Gulf of Aqaba (NE-SW extension and NW-SE compression). The grid search method over a range of focal depths indicates an optimum solution at 15 ± 1 km. To identify the causative fault plane, the aftershock hypocenters were relocated using the local waveform data and the double-difference technique. Considering the fault trends, the spatial distribution of relocated aftershocks demarcated a NS-oriented causative fault, in consistence with one of the nodal planes of the focal mechanism solution, emphasizing the dominant stress regime in the region. Following the Brune model, the estimates of source parameters exhibited fault lengths of 0.29 ≤ L ≤ 2.48 km, moment magnitudes of 3.0 ≤ Mw ≤ 5.0, and stress drops of 0.14 ≤ Δσ < 1.14 MPa, indicating a source scaling similar to the tectonic earthquakes related to plate boundaries. © 2017 Springer Science+Business Media Dordrecht

Al-Kahtany K.M.,King Saud University
Journal of African Earth Sciences | Year: 2017

The Middle Miocene reefal limestone of Wadi Waqb Member (Jabal Kibrit Formation) in northwest Saudi Arabia is unconformably overlaying the Precambrian basement rocks and/or Early Miocene siliciclastics. On the basis of field observations, microfacies analyses and fossil content, particularly scleractinian corals, the reefal limestone is composed of three depositional facies. These depositional facies are from base to top: 1) fore-reef facies, consists of hard, massive, marly coralline limestone with low diverse, small isolated corals heads, 2) reef-core facies, which consists of very hard, bioturbated coralline limestone with exclusively huge coral colonies of Porites and Tarbellastraea spp. and, 3) back reef facies, consists of sandy to pebbly massive, bioturbated limestone with very low diverse, scattered, small dendroid and massive heads of corals. The studied reefal limestone was deposited in fore-reef framework in an open marine environment with moderate to high energy conditions and changed upward to shallow marine facies with accumulation of skeletal grains by storms during regression. © 2017 Elsevier Ltd

The objective of this study was to investigate the antihyperglycaemic and antihyperlipidemic efficacy of Arabian coffee, Cardamom and Cloves on HFD induced diabetic mice. C57BL/6J mice that were fed a high fat (HFD) developed obesity, hyperglycemia and hyperinsulinemia compared with those that were fed a Standard pellet diet (SPD). Mice fed with HFD increased the levels of plasma glucose, insulin, glycosylated hemoglobin and a decrease in hemoglobin. The activities of carbohydrate metabolic enzymes such as glucose-6-phosphatase and fructose- 1,6-bisphosphatase increased while glucokinase activity and glycogen level decreased in HFD mice. Treatment with Arabian coffee, Cardamom and Cloves significantly reduced the plasma glucose, insulin and HbA1c and it also elevated the levels of Hb. Arabian coffee, cardamom and cloves supplementation to diabetic mice reverted back the activities of carbohydrate metabolizing enzyme in a significant manner and increased the liver glycogen level. The increased levels of lipid profile such as total cholesterol (TC), triglycerides (TG), phospholipids (PL) and free fatty acids (FFA) were observed in both the plasma and tissues of HFD-fed C57BL/6J diabetic mice. The plasma lipoproteins, very low density lipoproteins-cholesterol (VLDL-C) and low density lipoproteins-cholesterol (LDL-C) were significantly increased and the plasma levels of high density lipoproteins-cholesterol (HDL-C) were decreased in HFD-fed C57BL/6J diabetic mice. An HFD-induced C57BL/6J diabetic mouse treated with Arabian coffee, Cardamom and Cloves significantly reversed all these parameters towards normalcy. Moreover, combined effect of Arabian coffee, cardamom and cloves has more pronounced effect than their individual treatment. These findings suggest that Arabian coffee with cardamom and Cloves is having better antihyperglycaemic and antihyperlipidemic effect on HFD-fed C57BL/6J diabetic mice.

Altokhais T.,King Saud University
Urology Annals | Year: 2017

Circumcision is one of the most common procedures performed worldwide. Bleeding is one of the most common complications following male circumcision, and to decrease the risk of bleeding, electrosurgery may be utilized. However, the use of diathermy on the penis is controversial, and there are reported complications due to the use of electrosurgery for circumcision. The aim of this review is to evaluate the utilization and relative safety of monopolar and bipolar electrosurgery for circumcision in children. © 2017 Urology Annals.

Zaman K.,University of Wah | Abd-el Moemen M.,King Saud University
Renewable and Sustainable Energy Reviews | Year: 2017

The objective of the study is to examine the dynamic linkages among electricity production from renewable sources, permanent cropland, high technology exports, health expenditures, and carbon dioxide (CO2) emissions in the panel of 14 selected Latin America and the Caribbean countries, over the period of 1980–2013. The study employed panel unit root test, panel cointegration, panel least square, panel fixed effect model, panel random effect model, and panel two stage least square (2SLS) instrumental variables technique for robust inferences. The results confirmed the long-run relationship between the variables. The panel results indicate the effectiveness of high-technology exports that decreases the CO2 emissions, while electricity production, permanent cropland and health expenditures increase CO2 emissions, which deteriorates the environment. The study concludes with the support of long-term sustainable policies, which is imperative for sound growth in a panel of countries. © 2017 Elsevier Ltd

Zaman K.,University of Wah | Moemen M.A.-E.,King Saud University
Renewable and Sustainable Energy Reviews | Year: 2017

Pursuit of excellence in economic development, in the midst of damaging the natural environment, is a shameless growth. The economic impacts on environmental degradation are quite visible in industrialized economies where human health is compromised by rapid economic growth and energy induced emissions. This study examines the interrelationship between energy consumption, economic growth and carbon dioxide (CO2) emissions under the six alternative and plausible hypothesis including Environmental Kuznets Curve (EKC), Pollution Haven Hypothesis (PHH), population based emissions (IPAT), energy led emissions, sectoral growth emissions and Emissions emancipated Human Development Index (eHDI) in the context of low and middle income countries, high income countries and in aggregated panel, over the period of 1975–2015. The results supported the EKC hypothesis, IPAT hypothesis, energy induced emissions, and sectoral growth emissions in different regions of the world, while PHH and eHDI hypothesis does not confirm across regions. This study exclusively determines the key socio-economic and environmental problems in a large pool of the world economies to understand the need of development policy agenda for sustainable growth. © 2017 Elsevier Ltd

Diab D.M.,King Saud University | El Hindi K.M.,King Saud University
Applied Soft Computing Journal | Year: 2017

The Naive Bayes (NB) learning algorithm is simple and effective in many domains including text classification. However, its performance depends on the accuracy of the estimated conditional probability terms. Sometimes these terms are hard to be accurately estimated especially when the training data is scarce. This work transforms the probability estimation problem into an optimization problem, and exploits three metaheuristic approaches to solve it. These approaches are Genetic Algorithms (GA), Simulated Annealing (SA), and Differential Evolution (DE). We also propose a novel DE algorithm that uses multi-parent mutation and crossover operations (MPDE) and three different methods to select the final solution. We create an initial population by manipulating the solution generated by a method used for fine tuning the NB. We evaluate the proposed methods by using their resulted solutions to build NB classifiers and compare their results with the results of obtained from classical NB and Fine-Tuning Naïve Bayesian (FTNB) algorithm, using 53 UCI benchmark data sets. We name these obtained classifiers NBGA, NBSA, NBDE, and NB-MPDE respectively. We also evaluate the performance NB-MPDE for text-classification using 18 text-classification data sets, and compare its results with the results of obtained from FTNB, BNB, and MNB. The experimental results show that using DE in general and the proposed MPDE algorithm in particular are more convenient for fine-tuning NB than all other methods, including the other two metaheuristic methods (GA, and SA). They also indicate that NB-MPDE achieves superiority over classical NB, FTNB, NBDE, NBGA, NBSA, MNB, and BNB. © 2016

Invasion by the exotic species Prosopis juliflora has become a major threat to native plants in Saudi Arabia as the species continues its spread into different regions of the country. Ziziphus spina-christi is a native tree that is common in Saudi Arabia. The objective of this study was to determine how both species would benefit from the availability of sufficient resources without competition. To gain a better understanding of growth under such conditions, a greenhouse experiment was conducted in which seedlings of both species were grown under favorable conditions for 6 months. During this period, growth performance was evaluated three times at intervals of 30, 90, and 180 days. Growth performance varied between the two species during one or more of the studied periods. Significant differences between the species were observed for root mass fraction, number of root tips, root to shoot ratio, height, stem diameter, stem dry weight, stem mass fraction, leaf area, leaf mass fraction, and chlorophyll a and b contents. The relative growth rate (RGR) and relative height growth rate were higher in P. juliflora at 30–90 days, whereas leaf area ratio and net assimilation rate were higher for Z. spina-christi at 90–180 days. Remarkably, the RGR for diameter in P. juliflora was almost double that in Z. spina-christi at 30–90 days and 90–180 days. The results obtained reflect a strategic difference in the biomass allocation to different plant components by the two species, whereby P. juliflora allocates higher biomass to the stems and Z. spina-christi allocates higher biomass to the roots. © 2017, Universidade Federal de Uberlandia. All rights reserved.

Alhamdan A.A.,King Saud University
Malaysian Journal of Nutrition | Year: 2016

Introduction: Protein malnutrition increases the sensitivity to septic shock by impairing antioxidation and immune response. Based on the potent antioxidant effects of silymarin, the putative protective role of silymarin against sepsis-induced oxidative damage in protein malnourished rats was investigated. Methods: Adult male Wistar rats were subjected to protein malnutrition via a low-protein diet (8% protein), with and without silymarin supplementation (30 mg/kg/day) for four weeks, and compared to a control group on a 18% protein diet At end of the experiment, the animals received intraperitoneal injections (i.p.) of 0.1 mg/kg lipopolysaccharide (LPS) derived from Esdieridtia coil, and decapitation 24 h later. Albumin, C-reactive protein (CRP), total protein (TP), alkaline phosphates (A/CP ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), interleultine-lβ (IL-1β) and interleukine-6 (IL-6) levels were measured in serum. In the lungs and liver, thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) concentrations, superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST) activities were measured. Results: oxidative and inflammatory processes were significantly increased by the LPS injection and these changes were to a greater extent in the low-protein dietary group compared to control group. Silymarin supplementation in both dietary groups showed marked inhibition in these activities, although the affect was more prominent in the control group compared to the rats fed a low-protein diet. Conclusions: The study showed that silymarin protected against the impairment of antioxidation and immune response in protein malnourished rats, particularly in septic shock conditions.

Alkahtani S.A.,King Saud University
BMC Musculoskeletal Disorders | Year: 2017

Background: The aim of this study was to determine reference values for sarcopenia indices using different methods in healthy Saudi young men. Methods: Participants included 232 Saudi men aged between 20 and 35 years. The study measured anthropometric indices, blood pressure, hand grip strength, and lean muscle mass using dual-energy X-ray absorptiometry (DXA), and bioelectrical impedance analysis (BIA) was performed using Inbody 770 and Tanita 980 devices. Results: Using DXA, the mean value of appendicular lean mass divided by the height squared (ALM/ht2) was found to be 8.97 ± 1.23 kg/m2; hand grip strength measured 42.8 ± 7.6 kg. While the differences between DXA and BIA (Tanita) were significant for all parameters, the differences between DXA and Inbody values were significant only for ALM parameters. Inbody sensitivity and specificity values were 73% and 95.9%, respectively. The kappa (P = 0.80) and p values (P < 0.001) showed good agreement between Inbody and DXA, whereas Tanita sensitivity and specificity values were 54.2% and 98.3%, respectively. Bland-Altman plots for differences in lean mass values between Tanita, Inbody, and DXA methods showed very high bias for Tanita and DXA, with significant differences (P < 0.001). Conclusions: The cut-off values for sarcopenia indices for Saudi young men are different from those of other ethnicities. The use of tailored cut-off reference values instead of a general cut-off for BIA devices is recommended. © 2017 The Author(s).

Al-Hameed F.M.,King Saud University
Saudi Medical Journal | Year: 2017

The Middle East respiratory syndrome corona virus (MERS-CoV) is a novel positive sense singlestranded ribonucleic acid virus of the genus Beta corona virus. This virus was first isolated from a patient who died from severe respiratory illness in June 2012 in Jeddah, Kingdom of Saudi Arabia. We describe an unusual case of a 42 year old healthcare worker who was admitted to our Intensive Care Unit (ICU) King Abdul-Aziz Medical City, with MERS-CoV and severe acute respiratory distress Syndrome and developed a sudden-onset diabetes insipidus and spontaneous massive intracranial hemorrhage with intra-ventricular extension and tonsillar herniation. Computed angiogram of the brain did not reveal any aneurysm or structural defects. She never had uncontrolled hypertension, or coagulopathy, nor she received antiplatelets. We are reporting a rare case of structural neurological damage associated with MERS-CoV infection. © 2017, Saudi Arabian Armed Forces Hospital. All rights reserved.

Ahmed A.M.,King Saud University
Folia Morphologica (Poland) | Year: 2017

Background: The left ventricular hypertrophy (LVH) occurs in response to the haemodynamic overload in some physiological and pathological conditions. This study was designed to investigate the possible cardioprotective effect of simvastatin (SIM) treatment against isoproterenol (ISO)-induced LVH and the probable underlying mechanism in adult male Wistar rats. Materials and methods: Animals were allocated into four groups. Rats of control group received normal saline orally for 30 days and intraperitoneally for the last 7 days. Rats of SIM group received SIM orally (10 mg/kg/day in saline) for 30 days. Rats of ISO group received normal saline orally for 30 days and ISO intraperitoneally (5 mg/kg) for the last 7 days to induce LVH. Rats of ISO/SIM group received SIM for 30 days and ISO intraperitoneally for the last 7 days. At the end of the experiment, all animals were sacrificed by cervical decapitation under anaesthesia. Truncal blood was collected and serum was separated and used for biochemical assay. The heart was dissected and processed for histological and immunohistochemical studies. Results: The results of the present study confirmed the ISO-induced myocardial lesions including significant increase of heart weight (HW), heart weight/body weight (HW/BW) ratio, LVH, interstitial myocardial fibrosis (increased collagen types I and III), inflammatory cellular infiltration, necrosis of cardiomyocytes, and increased expression of inducible nitric oxide synthase (iNOS) and thioredoxin in cardiomyocytes. These changes were accompanied by significant increase in serum levels of troponin-T, creatine phosphokinase-MB (CPK-MB), tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). Co-administration of SIM to ISO-injected rats significantly reduced all these cardiac changes and serum biochemical markers in addition to marked depletion of iNOS and thioredoxin expression in cardiomyocytes. Conclusions: It is concluded that SIM co-administration attenuated ISO-induced cardiac lesions including LVH by inhibiting iNOS expression in cardiomyocytes. Copyright © 2017 Via Medica.

Dahshan M.H.,King Saud University
Telecommunication Systems | Year: 2017

This paper presents a robust data authentication scheme for protecting data integrity and availability in unattended wireless sensor networks. Such networks are vulnerable to several types of attacks. In particular, attackers can compromise a subset of nodes and use these nodes to transmit modified data or to prevent genuine data from being verified. The presented scheme combines security against data modification and denial of service attacks with traffic and storage efficiency. This is achieved by involving all sensor nodes in the network in the authentication process, implementing cooperative authentication with multiple authenticators, and using dual storage. Detailed analysis and extensive simulation tests show that our scheme achieves better performance compared to related schemes published in the literature in terms of traffic, storage, security against DoS attacks, and security against data replacement attacks. © 2017 Springer Science+Business Media New York

El Mouzan M.I.,King Saud University
Annals of Saudi medicine | Year: 2017

BACKGROUND: Assessment of growth using Z-score methods is important for clinical care and research, yet growth reference Z-score data for preschool Saudi children are not available.OBJECTIVE: Establish Z-score tables and corresponding growth charts.DESIGN: Uses data from a national survey in 2004-2005.SETTING: Community-based random sample of preschool Saudi children.SUBJECTS AND METHODS: Raw data from the previous nationally representative sample were analyzed using the L, M, and S statistical methods to calculate Z-scores of growth.MAIN OUTCOME MEASURE(S): Z-scores reference values for weight, length/height, head circumference, weight for length/height, and body mass index for age for boys and girls from birth to 60 months of age.RESULTS: For 15 601 Saudi children (7896, 50.6 % boys) Z-score tables and graphs from birth to 60 months of age were derived for boys and girls. The tables and graphs include weight for age, length/height for age, head circumference for age, weight for length/height, and BMI for age.CONCLUSION: Z-score reference data on the growth of preschool Saudi infants and children is essential for healthcare and research.LIMITATION: Does not include regional variations.

Bin-Omran S.,King Saud University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2017

A first-principles-derived effective Hamiltonian approach is used to reveal the temperature-versus-misfit strain phase diagram of an epitaxial (Ba0.50Sr0.50)TiO3 dot under different electrical boundary conditions. The results indicate that the electrical polarization and toroidal moment are highly sensitive to the applied strain and/or electrical boundary conditions, resulting in a wide variety of phases that are not found in a free-standing BST dot and in bulk. The calculations indicate that within a narrow range of surface charge screening an intermediate phase in which the polarization and toroidal moment coexist. The dependences of the electrical polarization, toroidal moment and dielectric permittivity on the misfit strain and electrical boundary conditions at room temperature are also investigated and compared with the available theoretical predictions and experimental measurements. © 2016 Elsevier B.V.

With the growing use of the machine-to-machine (M2M) communication and the unlicensed band by advanced long term evolution (LTE-A) networks, known as LTE unlicensed (LTE-U), demand for resource access strategy is rapidly increasing and has recently been attracting considerable attention of mobile operators. The requirement set by 3rd generation partnership project in the release 11 about LTE standards will allow LTE-U and other unlicensed band access technology to peacefully coexist and operate in the same unlicensed band. LTE-U supports not only the human-to-human (H2H) communication but also the M2M communication. In this paper, a new MAC protocol for LTE-U that allow friendly co-existence of H2H with M2M communications working in unlicensed bands is presented. The proposed MAC mechanisms is designed to ensure an efficient and fair channel access as well as enabling better H2H/M2M coexistence. The throughput performance of both H2H and M2M systems is evaluated analytically and by simulation. The impact of H2H/M2M transmissions periods and spectrum sensing time on the throughput performance of H2H and M2M systems are also studied. © 2017 Springer Science+Business Media New York

Vashist S.K.,National University of Singapore | Zheng D.,National University of Singapore | Al-Rubeaan K.,King Saud University | Luong J.H.T.,NRC Biotechnology Research Institute | Sheu F.-S.,National University of Singapore
Biotechnology Advances | Year: 2011

Electrochemical (EC) sensing approaches have exploited the use of carbon nanotubes (CNTs) as electrode materials owing to their unique structures and properties to provide strong electrocatalytic activity with minimal surface fouling. Nanofabrication and device integration technologies have emerged along with significant advances in the synthesis, purification, conjugation and biofunctionalization of CNTs. Such combined efforts have contributed towards the rapid development of CNT-based sensors for a plethora of important analytes with improved detection sensitivity and selectivity. The use of CNTs opens an opportunity for the direct electron transfer between the enzyme and the active electrode area. Of particular interest are also excellent electrocatalytic activities of CNTs on the redox reaction of hydrogen peroxide and nicotinamide adenine dinucleotide, two major by-products of enzymatic reactions. This excellent electrocatalysis holds a promising future for the simple design and implementation of on-site biosensors for oxidases and dehydrogenases with enhanced selectivity. To date, the use of an anti-interference layer or an artificial electron mediator is critically needed to circumvent unwanted endogenous electroactive species. Such interfering species are effectively suppressed by using CNT based electrodes since the oxidation of NADH, thiols, hydrogen peroxide, etc. by CNTs can be performed at low potentials. Nevertheless, the major future challenges for the development of CNT-EC sensors include miniaturization, optimization and simplification of the procedure for fabricating CNT based electrodes with minimal non-specific binding, high sensitivity and rapid response followed by their extensive validation using "real world" samples. A high resistance to electrode fouling and selectivity are the two key pending issues for the application of CNT-based biosensors in clinical chemistry, food quality and control, waste water treatment and bioprocessing. © 2010 Elsevier Inc.

Hussain S.S.,University of Adelaide | Ali M.,Bahauddin Zakariya University | Ahmad M.,South Australian Research And Development Institute | Siddique K.H.M.,University of Western Australia | Siddique K.H.M.,King Saud University
Biotechnology Advances | Year: 2011

Polyamines (PAs) are ubiquitous biogenic amines that have been implicated in diverse cellular functions in widely distributed organisms. In plants, mutant and transgenic plants with altered activity pointed to their involvement with different abiotic and biotic stresses. Furthermore, microarray, transcriptomic and proteomic approaches have elucidated key functions of different PAs in signaling networks in plants subjected to abiotic and biotic stresses, however the exact molecular mechanism remains enigmatic. Here, we argue that PAs should not be taken only as a protective molecule but rather like a double-faced molecule that likely serves as a major area for further research efforts. This review summarizes recent advances in plant polyamine research ranging from transgenic and mutant characterization to potential mechanisms of action during environmental stresses and diseases. © 2011 Elsevier Inc.

Ola M.S.,King Saud University | Nawaz Mohd.,King Saud University | Ahsan H.,Jamia Millia Islamia University
Molecular and Cellular Biochemistry | Year: 2011

Apoptosis, or programmed cell death, plays a pivotal role in the elimination of unwanted, damaged, or infected cells in multicellular organisms and also in diverse biological processes, including development, cell differentiation, and proliferation. Apoptosis is a highly regulated form of cell death, and dysregulation of apoptosis results in pathological conditions including cancer, autoimmune and neurodegenerative diseases. The Bcl-2 family proteins are key regulators of apoptosis, which include both anti- and pro-apoptotic proteins, and a slight change in the dynamic balance of these proteins may result either in inhibition or promotion of cell death. Execution of apoptosis by various stimuli is initiated by activating either intrinsic or extrinsic pathways which lead to a series of downstream cascade of events, releasing of various apoptotic mediators from mitochondria and activation of caspases, important for the cell fate. In view of recent research advances about underlying mechanism of apoptosis, this review highlights the basics concept of apoptosis and its regulation by Bcl-2 family of protein. Furthermore, this review discusses the interplay of various apoptotic mediators and caspases to decide the fate of the cell. We expect that this review will add to the pool of basic information necessary to understand the mechanism of apoptosis which may implicate in designing better strategy to develop biomedical therapy to control apoptosis. © 2011 Springer Science+Business Media, LLC.

Al-Othman Z.A.,King Saud University | Al-Warthan A.,King Saud University | Ali I.,Jamia Millia Islamia University
Journal of Separation Science | Year: 2014

During the last decade, chiral monolithic stationary phases have been prepared and used for rapid enantioseparations in CEC and HPLC. Various chiral selectors are used to prepare these CSPs. The preparation, properties, and applications of these CSPs are discussed in this paper. Attempts have been made to describe optimization strategies and the chiral recognitionmechanisms. A comparison of chiral separations in CEC and HPLC is described. Efforts have also been made to predict the future perspectives and challenges of chiral monolithic stationary phases. The most effective chiral selectors include polysaccharides, cyclodextrins, andmacrocyclic glycopeptide antibiotics. These chiral phases produced acceptable analytical enantiomeric separation of a variety of racemates. However, the development of these CSPs for preparative-scale separations is needed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhani K.,University of Sfax | Ben Bacha H.,King Saud University
Renewable Energy | Year: 2010

This paper tackles an experimental investigation of a new solar desalination prototype using the humidification dehumidification principle at the weather conditions of Sfax City, Tunisia. The prototype is designed and constructed at the national engineering school of Sfax to conduct this experimental investigation under different meteorological and operating parameters. It is composed of a flat plate solar air collector, a flat plate solar water collector, a humidifier, an evaporation tower and a condensation tower. An economic analysis was conducted, since it affects the final cost of produced water, to determine both the cost of fresh water production and the payback period of the experimental setup. Although a system may be technically very efficient, it may not be economic. The experimental investigation of the dynamic behaviour of the solar desalination unit during summer season (June, July and August) and during a typical day in July was carried to study the temporal evolutions of the temperature of air and water and the relative humidity at the inlet and the outlet of each component of the system. © 2010 Elsevier Ltd.

Frontera A.,University of the Balearic Islands | Gamez P.,University of Barcelona | Mascal M.,University of California at Davis | Mooibroek T.J.,Leiden University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Supramolecular chemistry is a field of scientific exploration that probes the relationship between molecular structure and function. It is the chemistry of the noncovalent bond, which forms the basis of highly specific recognition, transport, and regulation events that actuate biological processes. The classic design principles of supramolecular chemistry include strong, directional interactions like hydrogen bonding, halogen bonding, and cation-π complexation, as well as less directional forces like ion pairing, π-π, solvophobic, and van der Waals potentials. In recent years, the anion-π interaction (an attractive force between an electron-deficient aromatic π system and an anion) has been recognized as a hitherto unexplored noncovalent bond, the nature of which has been interpreted through both experimental and theoretical investigations. The design of selective anion receptors and channels based on this interaction represent important advances in the field of supramolecular chemistry. The objectives of this Review are 1) to discuss current thinking on the nature of this interaction, 2) to survey key experimental work in which anion-π bonding is demonstrated, and 3) to provide insights into the directional nature of anion-π contact in X-ray crystal structures. As easy as π systems found it to bond with cations, they concealed their attraction to anions until they were spotted together in too many crystal structures for it to be mere coincidence. Today, the anion-π relationship has an established place in the repertory of noncovalent interactions. Extensive theoretical and experimental studies illuminate the physical nature of the interaction and its utility in the design of hosts, and the engineering of solid-state structures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ming R.,University of Illinois at Urbana - Champaign | Bendahmane A.,French National Institute for Agricultural Research | Bendahmane A.,King Saud University | Renner S.S.,Ludwig Maximilians University of Munich
Annual Review of Plant Biology | Year: 2011

Sex chromosomes in land plants can evolve as a consequence of close linkage between the two sex determination genes with complementary dominance required to establish stable dioecious populations, and they are found in at least 48 species across 20 families. The sex chromosomes in hepatics, mosses, and gymnosperms are morphologically heteromorphic. In angiosperms, heteromorphic sex chromosomes are found in at least 19 species from 4 families, while homomorphic sex chromosomes occur in 20 species from 13 families. The prevalence of the XY system found in 44 out of 48 species may reflect the predominance of the evolutionary pathway from gynodioecy towards dioecy. All dioecious species have the potential to evolve sex chromosomes, and reversions back from dioecy to various forms of monoecy, gynodioecy, or androdioecy have also occurred. Such reversals may occur especially during the early stages of sex chromosome evolution before the lethality of the YY (or WW) genotype is established. Copyright © 2011 by Annual Reviews. All rights reserved.

Halwani R.,King Saud University | Al-Muhsen S.,King Saud University | Hamid Q.,King Saud University | Hamid Q.,University of Sfax
Chest | Year: 2013

T helper 17 (Th17) cytokines are now widely believed to be critical for the regulation of various chronic immune diseases. Investigations have revealed a signifi cant role for IL-17 cytokines in regulating infl ammation and modulating lung and airway structural cells in asthma and COPD. In this review, our current understanding of the role of Th17-associated cytokines in airway diseases is summarized. Therapeutic approaches targeting IL-17 during asthma and COPD are also discussed. CHEST 2013; 143 ( 2 ): 494 - 501 © 2013 American College of Chest Physicians.

Techen N.,National University of Pharmacy | Parveen I.,National University of Pharmacy | Khan I.A.,National University of Pharmacy | Khan I.A.,King Saud University
Current Opinion in Biotechnology | Year: 2014

Because of the increasing demand for herbal remedies and for authentication of the source material, it is vital to provide a single database containing information about authentic plant materials and their potential adulterants. The database should provide DNA barcodes for data retrieval and similarity search. In order to obtain such barcodes, several molecular methods have been applied to develop markers that aid with the authentication and identification of medicinal plant materials. In this review, we discuss the genomic regions and molecular methods selected to provide barcodes, available databases and the potential future of barcoding using next generation sequencing. © 2013 Elsevier Ltd.

Aloui C.,King Saud University
Physica A: Statistical Mechanics and its Applications | Year: 2015

In this article, we propose a wavelet-based approach to accommodate the stylized facts and complex structure of financial data, caused by frequent and abrupt changes of markets and noises. Specifically, we show how the combination of both continuous and discrete wavelet transforms with traditional financial models helps improve portfolio's market risk assessment. In the empirical stage, three wavelet-based models (wavelet-EGARCH with dynamic conditional correlations, wavelet-copula, and wavelet-extreme value) are considered and applied to crude oil price and US dollar exchange rate data. Our findings show that the wavelet-based approach provides an effective and powerful tool for detecting extreme moments and improving the accuracy of VaR and Expected Shortfall estimates of oil-exchange rate portfolios after noise is removed from the original data. © 2015 Elsevier B.V. All rights reserved.

Caliskan H.,Ege University | Dincer I.,University of Ontario Institute of Technology | Hepbasli A.,King Saud University
Energy Conversion and Management | Year: 2012

In this study, three various novel air coolers based on M-Cycle are evaluated using energy and exergy analyses based efficiency assessments along with environmental impact and sustainability parameters. The M-Cycle systems are considered to cool a building room air while their inlet air parameters are same, but outlet cooled air parameters are different. Systems I and III draw electricity directly taken from an electric grid in the building while System II, which is stand alone system, produces and draws electricity from its solar PV panels. In the energy analysis, wet bulb effectiveness, cooling capacity, Coefficient of Performance (energetic COP) and Primary Energy Ratio (PER) are found. In the exergy analysis, exergy input and output rates, exergy loss rate, exergy destruction rate, Exergetic Coefficient of Performance (COP ex), Primary Exergy Ratio (PE xR) and exergy efficiency are obtained for six different dead state temperatures changing between 10 °C and 35 °C. Also, sustainability assessments of the systems are obtained using sustainability index (SI) tool for these various dead state temperatures. Finally, environmental assessments of the systems are calculated from their greenhouse gas (GHG) emissions (gCO 2/kW h) due to their electricity consumptions. Maximum exergy efficiencies and sustainability assessments are found to be 35.13% and 1.5415 for System III and 34.94% and 1.5372 for System II, respectively. GHG emissions of the systems are calculated to be 2119.68 gCO 2/day, 153.6 gCO 2/day and 3840 gCO 2/day for Systems I, II and III respectively. So, System II becomes a good choose to prevent the global warming and to attain sustainable future. © 2011 Elsevier Ltd. All rights reserved.

Clusella-Trullas S.,Stellenbosch University | Blackburn T.M.,UK Institute of Zoology | Blackburn T.M.,King Saud University | Chown S.L.,Stellenbosch University
American Naturalist | Year: 2011

Determining organismal responses to climate change is one of biology's greatest challenges. Recent forecasts for future climates emphasize altered temperature variation and precipitation, but most studies of animals have largely focused on forecasting the outcome of changes in mean temperature. Theory suggests that extreme thermal variation and precipitation will influence species performance and hence affect their response to changes in climate. Using an information-theoretic approach, we show that in squamate ectotherms (mostly lizards and snakes), two fitness-influencing components of performance, the critical thermal maximum and the thermal optimum, are more closely related to temperature variation and to precipitation, respectively, than they are to mean thermal conditions. By contrast, critical thermal minimum is related to mean annual temperature. Our results suggest that temperature variation and precipitation regimes have had a strong influence on the evolution of ectotherm performance, so that forecasts for animal responses to climate change will have to incorporate these factors and not only changes in average temperature. ©2011 by The University of Chicago.

Casini A.,University of Groningen | Reedijk J.,Leiden University | Reedijk J.,King Saud University
Chemical Science | Year: 2012

A critical discussion is presented about the possible role of Pt-protein interactions in the mechanisms of action of platinum anticancer compounds. Although, since 40 years from its discovery, cisplatin and analogues are believed to exert their therapeutic effects via direct interactions with nucleic acids, several proteins/enzymes have recently appeared to be involved in the compounds' overall pharmacological and toxicological profiles, apart from classical serum transport proteins and metal detoxification systems. As an example, the emerging role of zinc finger proteins is noteworthy in the activity of platinum drugs. Moreover, the pursuit of novel platinum candidates that selectively target enzymes is now the subject of intense investigation in medicinal bioinorganic chemistry and chemical biology. An overview is presented of the most representative studies in the field, with particular focus on the characterization of the Pt-protein interactions at a molecular level, using different biophysical and analytical methods. © 2012 The Royal Society of Chemistry.

Schwartz P.J.,University of Pavia | Schwartz P.J.,University of Cape Town | Schwartz P.J.,Stellenbosch University | Schwartz P.J.,King Saud University | And 5 more authors.
Journal of the American College of Cardiology | Year: 2013

There are few areas in cardiology in which the impact of genetics and genetic testing on clinical management has been as great as in cardiac channelopathies, arrhythmic disorders of genetic origin related to the ionic control of the cardiac action potential. Among the growing number of diseases identified as channelopathies, 3 are sufficiently prevalent to represent significant clinical and societal problems and to warrant adequate understanding by practicing cardiologists: long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome. This review will focus selectively on the impact of genetic discoveries on clinical management of these 3 diseases. For each disorder, we will discuss to what extent genetic knowledge and clinical genetic test results modify the way cardiologists should approach and manage affected patients. We will also address the optimal use of genetic testing, including its potential limitations and the potential medico-legal implications when such testing is not performed. We will highlight how important it is to understand the ways that genotype can affect clinical manifestations, risk stratification, and responses to the therapy. We will also illustrate the close bridge between molecular biology and clinical medicine, and will emphasize that consideration of the genetic basis for these heritable arrhythmia syndromes and the proper use and interpretation of clinical genetic testing should remain the standard of care. © 2013 by the American College of Cardiology Foundation.

Al-Sanea S.A.,King Saud University | Zedan M.F.,King Saud University
Applied Energy | Year: 2013

Effects of type of masonry material and surface absorptivity to solar radiation on critical thermal mass thickness in insulated building walls are investigated for a fixed wall nominal thermal resistance (Rn-value). The concepts of "thermal-mass energy-savings potential" (Δ) and "critical thermal mass thickness" (Lmas,cr), developed in a previous study, are utilized to determine the thermal mass thickness required for a desired percentage energy savings. Transmission loads are calculated under the climatic data of Riyadh, assuming steady periodic conditions, by using a previously validated computer model. Effects of masonry materials are investigated by using solid and hollow concrete blocks, while surface absorptivity (λ) influence is studied for λ=0.4 and 0.2. Walls are considered where thermal mass is located on the inside or on the outside relative to insulation layer. Thermal mass thickness is varied between 0 and 50cm while keeping Rn-value constant. The results show that for a given critical thermal mass thickness, higher energy savings potential is obtained with: (i) walls with solid concrete blocks, (ii) walls with lower surface absorptivity, and (iii) walls with inside thermal mass. Charts are developed for Lmas,cr versus Δ under the different conditions for the benefit of building envelope designers. © 2012 Elsevier Ltd.

Al-Sanea S.A.,King Saud University | Zedan M.F.,King Saud University
Applied Energy | Year: 2012

Effects of varying amount and location of thermal mass on dynamic heat-transfer characteristics of insulated building walls with same nominal resistance (Rn-value) are investigated numerically under steady periodic conditions using climatic data of Riyadh. Concepts of " thermal-mass energy-savings potential" (Δ) and " critical thermal-mass thickness" (Lmas,cr) are developed and utilized in order to determine thermal mass thickness (Lmas) required for a selected desirable percentage of energy savings. Results show that daily transmission loads are not affected by Lmas for representative days of months in summer and winter. However, for moderate months, daily cooling and heating transmission loads decrease with increasing Lmas and either diminish to zero or be reduced asymptotically to constant values. For all months, peak transmission loads and decrement factor decrease, while time lag increases, with increasing Lmas. For a given Lmas, a wall with outside insulation gives better overall performance than a wall with inside insulation. While Rn-value is constant, wall dynamic resistance (Rd-value) changes and represents actual variations in transmission loads. For Δ in the range 70-99%, Lmas,cr ranges between 6 and 30cm by using heavyweight concrete. It is found that maximum savings in yearly cooling and heating transmission loads are about 17% and 35%, respectively, as a result of optimizing Lmas for same Rn-value. It is recommended that building walls should contain Lmas,cr that corresponds to high Δ (≈95%) and with insulation placed on outside for applications with continuously operating year-round AC. © 2011 Elsevier Ltd.

Alfaleh K.,King Saud University | Anabrees J.,Sulaiman AlHabib Medical Group
Evidence-Based Child Health | Year: 2014

Background: Necrotizing enterocolitis (NEC) and nosocomial sepsis are associated with increased morbidity and mortality in preterm infants. Through prevention of bacterial migration across the mucosa, competitive exclusion of pathogenic bacteria, and enhancing the immune responses of the host, prophylactic enteral probiotics (live microbial supplements) may play a role in reducing NEC and the associated morbidity. Objectives: To compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe NEC or sepsis, or both, in preterm infants. Search methods: For this update, searches were made of MEDLINE (1966 to October 2013), EMBASE (1980 to October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 10), and abstracts of annual meetings of the Society for Pediatric Research (1995 to 2013). Selection criteria: Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age or < 2500 g birth weight, or both, were considered. Trials were included if they involved enteral administration of any live microbial supplement (probiotics) and measured at least one prespecified clinical outcome. Data collection and analysis: Standard methods of The Cochrane Collaboration and its Neonatal Group were used to assess the methodologic quality of the trials and for data collection and analysis. Main results: Twenty-four eligible trials were included. Included trials were highly variable with regard to enrolment criteria (that is birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) (typical relative risk (RR) 0.43, 95% confidence interval (CI) 0.33 to 0.56; 20 studies, 5529 infants) and mortality (typical RR 0.65, 95% CI 0.52 to 0.81; 17 studies, 5112 infants). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.91, 95% CI 0.80 to 1.03; 19 studies, 5338 infants). The included trials reported no systemic infection with the supplemental probiotics organism. Probiotics preparations containing either lactobacillus alone or in combination with bifidobacterium were found to be effective. Authors' conclusions: Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our updated review of available evidence strongly supports a change in practice. Head to head comparative studies are required to assess the most effective preparations, timing, and length of therapy to be utilized. © 2014 John Wiley & Sons, Ltd.

The present disclosure generally relates to devices and procedures for the development of glucose oxidase-bound electrodes by a covalent binding of glucose oxidase on amine-functionalized electrodes. More particularly, the present disclosure is related to covalently-bound enzyme-coated electrodes that are leach-proof and highly stable for continuous glucose monitoring. The glucose oxidase-bound electrodes are employed for the development of a mediator-less electrochemical glucose sensing procedure having no interference from biological substances and drugs.

Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: INCO-2009-1.1 | Award Amount: 2.62M | Year: 2010

INCONET-GCC aims to develop and support the bi-regional dialogue by bringing together policymakers and stakeholders of the GCC and EU Member States. It aims to create a dialogue and action platform to identify common interests in research areas, set up S&T priorities, support capacity building activities, and enhance the interaction between different cooperation instruments of the EC and EU Member States. It will promote actions in order to monitor, develop, promote and contribute to the creation of synergies among the various S&T cooperation programmes between the GCC and the EU Member States, and foster the participation of the GCC in the FP7, CIP, etc. An observatory of EU-GCC cooperation in S&T will be created in the project framework. The main outputs of INCONET-GCC will be INCONET-GCC open networking platform for policy dialogue and the future S&T, Contribution of INCONET-GCC to the EU Strategic Framework for International Cooperation is S&T, Collaborative plan in S&T policy advisory contributing to the decisions of the GCC-EU Joint Council, INCONET-GCC White Paper, Integration of GCC NCPs with EU NCP network, INCONET-GCC roadmap and sustainability report, Organisation of International Conference and dissemination events. INCONET-GCC will be achieved through a high quality, recognized value and expertise consortium. Consortium roles and expertise are complementary and allows for a balanced effort allocation across its the different objectives. Partners coming from distinguished institutions in EU and GCC region and includes representatives of all countries of the Arabian Peninsula, which politically includes the 6 GCC states and Yemen, which repeatedly seeks to join the GCC six-country block. The Ministry of Education (Egypt) and the Ministry of Higher Education (Morocco) are MIRA partners that will act as the liaison with MIRA project and their cultural background is close to those of GCC region. The consortium is flexible and easily manageable.

Terramark Markencreation Gmbh and King Saud University | Date: 2010-03-25

This invention is concerned with the use of date syrup used as a binder (agglutinant) for solid dosage forms, such as tablets. The features of the granules and the tablets have been studied in comparison with granules and tablets which use different types of agglutinants such as starch paste and sucrose syrup and the results have shown that the use of date syrup as a binder for tablets yields results superior to other kinds of binders. In addition, date syrups gives the granules and tablets a fair color, good taste, distinct and pleasant odor, and it is favorable in regards to shape and taste by patients.

Shehata A.I.,King Saud University
Oncogene | Year: 2013

Cancer-associated fibroblasts (CAFs), the most abundant and probably the most active cellular component of breast cancer-associated stroma, promote carcinogenesis through paracrine effects; however, the molecular basis remains elusive. We have shown here that p16 INK4A expression is reduced in 83% CAFs as compared with their normal adjacent counterparts cancer-free tissues isolated from the same patients. This decrease is mainly due to AUF1-dependent higher turnover of the CDKN2A mRNA in CAFs. Importantly, p16 INK4A downregulation using specific siRNA activated breast fibroblasts and increased the expression/secretion levels of stromal cell-derived factor 1 (SDF-1) and matrix metalloproteinase (MMP)-2. Consequently, media conditioned with these cells stimulated the proliferation of epithelial cells. Furthermore, the migration/invasion of breast cancer cells was also enhanced in an SDF-1-dependent manner. This effect was mediated through inducing an epithelial-mesenchymal transition state. By contrast, increase in p16 INK4A level through ectopic expression or AUF1 downregulation, reduced the secreted levels of SDF-1 and MMP-2 and suppressed the pro-carcinogenic effects of CAFs. In addition, p16 INK4A-defective fibroblasts accelerated breast tumor xenograft formation and growth rate in mice. Importantly, tumors formed in the presence of p16 INK4A-defective fibroblasts exhibited higher levels of active Akt, Cox-2, MMP-2 and MMP-9, showing their greater aggressiveness as compared with xenografts formed in the presence of p16 INK4A-proficient fibroblasts. These results provide the first indication that p16 INK4A downregulation in breast stromal fibroblasts is an important step toward their activation. © 2013 Macmillan Publishers Limited.

Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: KBBE.2010.3.5-02 | Award Amount: 1.26M | Year: 2011

More than water scarcity, diseases and civil wars, Africa is also the least wealthy continent, in terms of economic and financial resources. These combined and tightly linked problems have led to a restricted range of choices, affordable for African countries, to deal particularly with the water issue, as a major topic. Polluted water treatment before use has been their almost unique solution to deal with a growing water scarcity. The treatment of water and elimination of pollutants, mainly pathogenic organisms, xenobiotics and heavy metals, although itself presents significant challenges, is crucial for human health and environmental considerations. However, most regions in developing countries cannot afford the costs of advanced and specialized systems. Numerous water cleaning methods are based in natural, plants or micro-organisms, biochemical processes. Biotechnology is a useful tool that is delivering improved products and process for environmental sustainability, and promises a range of benefits to manage the industrial WW economically and effectively around the world. Some biotechnological techniques are quite sophisticated but others are simple, cost effective and adapted to local conditions and resources of developing countries. These natural biological treatment systems include lagooning, land treatment, phytodepuration, or constructed wetlands systems. They can be applied as secondary or tertiary purification treatment, allowing the removal of pathogenic microorganisms and the degradation of the organic pollutants, so that waste water can be recycled for irrigation and domestic use and hence reduce the pressure on the hydric resources. Other biotechnological techniques to be taken into account within this proposal are biofiltration, membrane bioreactors and algae and other aquatic crops application for wastewater purification.

Agency: European Commission | Branch: FP7 | Program: CP-CSA | Phase: ENERGY.2013.10.1.10 | Award Amount: 21.20M | Year: 2014

Concentrating Solar Thermal Energy encompasses Solar Thermal Electricity (STE), Solar Fuels, Solar Process Heat and Solar Desalination that are called to play a major role in attaining energy sustainability in our modern societies due to their unique features: 1) Solar energy offers the highest renewable energy potential to our planet; 2) STE can provide dispatchable power in a technically and economically viable way, by means of thermal energy storage and/or hybridization, e.g. with biomass. However, significant research efforts are needed to achieve this goal. This Integrated Research Programme (IRP) engages all major European research institutes, with relevant and recognized activities on STE and related technologies, in an integrated research structure to successfully accomplish the following general objectives: a) Convert the consortium into a reference institution for concentrating solar energy research in Europe, creating a new entity with effective governance structure; b) Enhance the cooperation between EU research institutions participating in the IRP to create EU added value; c) Synchronize the different national research programs to avoid duplication and to achieve better and faster results; d) Accelerate the transfer of knowledge to industry in order to maintain and strengthen the existing European industrial leadership in STE; e) Expand joint activities among research centres by offering researchers and industry a comprehensive portfolio of research capabilities, bringing added value to innovation and industry-driven technology; f) Establish the European reference association for promoting and coordinating international cooperation in concentrating solar energy research. To that end, this IRP promotes Coordination and Support Actions (CSA) and, in parallel, performs Coordinated Projects (CP) covering the full spectrum of current concentrating solar energy research topics, selected to provide the highest EU added value and filling the gaps among national programs.

Barakah D.M.,Ministry of Health | Ammad-Uddin M.,King Saud University
Proceedings - 3rd International Conference on Intelligent Systems Modelling and Simulation, ISMS 2012 | Year: 2012

Wireless body area network has gained much interest and became emerging technology at health service facilities due to its wide range of utility and vital role to improve the human health. In this research paper, we are conducting a comprehensive survey of wireless Body Area Network (WBAN) and also introducing a virtual doctor server (VDS) in existing WBAN architecture. Existing architecture of WBAN consists of: wireless sensor, wireless actuator node, wireless central unit and wireless Personal Device (PD). Personal Digital Assistant (PDA) or smart phone can be used as PD. Based on the existing architecture mentioned above, we propose a design concept for a virtual doctor server (VDS) to support various patient health care services. VDS will keep the historical data about the patient, generate the daily tips and advices for him, call the doctor or emergency squad if required and can provide first aid assistance instructions on patient or any of his close relative's PDA's. © 2012 IEEE.

Khan A.S.,University of Maryland Baltimore County | Baig M.,King Saud University | Choi S.-H.,Sunchon National University | Yang H.-S.,Sunchon National University | Sun X.,Pacific Northwest National Laboratory
International Journal of Plasticity | Year: 2012

Measured responses of advanced high strength steels (AHSS) and their tailor welded blanks (TWBs), over a wide range of strain-rates (10 -4 to 10 3 s -1) are presented. The steels investigated include transformation induced plasticity (TRIP), dual phase (DP), and drawing quality (DQ) steels. The TWBs include DQ-DQ and DP-DP laser welds. A tensile split Hopkinson pressure bar (SHPB) was used for the dynamic experiments. AHSS and their TWB's were found to exhibit positive strain-rate sensitivity. The Khan-Huang-Liang (KHL) constitutive model is shown to correlate and predict the observed responses reasonably well. Micro-texture characterization of DQ steels, DQ-DQ and DP-DP laser welds were performed to investigate the effect of strain-rate on texture evolution of these materials. Electron backscatter diffraction (EBSD) technique was used to analyze the micro-texture evolution and kernel average misorientation (KAM) map. Measurement of micro-hardness profile across the cross section of tensile samples was conducted to understand the effect of initial microstructure on ductility of laser weld samples. © 2011 Elsevier Ltd. All rights reserved.

Aldalbahi A.,University of Wollongong | Aldalbahi A.,King Saud University | In Het Panhuis M.,University of Wollongong
Carbon | Year: 2012

The electrical and mechanical characteristics of composite materials prepared using evaporative casting and vacuum filtration of carbon nanotubes (CNTs) dispersed in the biopolymer τ-carrageenan (IC) are reported. It is demonstrated that the contact angle of water with films is proportional to the CNT mass and volume fraction, which is used to compare the properties of buckypapers with those of evaporative cast films. Multi-walled carbon nanotube films were found to exhibit higher conductivity values compared to those observed for single-walled carbon nanotubes composites at comparable contact angle values up to true nanotube volume fraction of 0.12. Buckypapers prepared by varying the absolute amount of CNT mass while keeping the IC amount of mass constant, were found to be more robust and conducting compared to evaporative cast films. In contrast, buckypapers prepared by changing the amount of IC mass while keeping the CNT amount of mass constant were found to be more conducting, but less robust compared to evaporative cast films. It is suggested that the electrical characteristics of these gel-carbon nanotube materials are determined by the relative amounts of mass (or volume) of CNTs and polymer, while the mechanical characteristics are governed by the absolute amounts of mass (or volume). © 2011 Elsevier Ltd. All rights reserved.

News Article | December 6, 2016
Site: www.prnewswire.co.uk

RIYADH, Saudi Arabia, Dec. 6, 2016 /PRNewswire/ -- Cognizant (NASDAQ: CTSH), a leading global provider of information technology, consulting and business process services, today announced the expansion of its operations in the Kingdom of Saudi Arabia (KSA) with the opening of a new office in Riyadh. Cognizant's expanded presence in KSA will enhance its existing operations in the Middle East and further enable Cognizant's clients to leverage the technical and business capabilities available in the region for building digital businesses, operations and systems. Cognizant currently employs more than 200 professionals in KSA, delivering a broad range of services—across digital business, operations, and systems and technology—to more than 25 leading organisations in industry sectors such as financial services, insurance, energy, utilities, telecommunications, and retail. "We congratulate Cognizant on the inauguration of its new office in Riyadh," said Meletis Meletiou, Chief Financial Officer at Kudu Company, a leading restaurant chain in KSA. "In working with us on a key ERP programme, Cognizant has proven itself to be a reliable and highly professional strategic partner who combines deep business and technology capabilities and experience. We thank Cognizant for its hard work and collaborative approach to helping us further strengthen our market leadership through greater efficiency, reduced operational costs and superior performance." "We started operations in KSA in 2011 and have steadily grown our presence and investment in the country," said Narayan Iyer, Vice President, Middle East and India, Cognizant. "Our expansion in KSA underscores our confidence in the country's talent pool and its ability to help our clients drive not just operational efficiencies, but also digital transformation for the needs of tomorrow. We will continue to work closely with the academia in KSA and build talent across our full range of services by helping STEM (science, technology, engineering and mathematics) graduates become software professionals of global standards and work on helping clients navigate the shift to the digital era." In 2012, Cognizant launched its graduate recruitment programme in KSA to hire entry-level technical and management talent from premier institutions in the country and has been hiring graduates from institutions such as King Saud University, King Fahad University of Petroleum and Minerals, King Faisal University, King Khalid University, Al-Imam Muhammad Ibn Saud Islamic University, and Alyammamah University. As part of its commitment to building talent for the future, Cognizant provides technical and soft skills training to entry-level hires in line with global benchmarks and deploys them to technology and consulting projects upon the successful completion of the training. The objective of this uniquely designed programme is to create a young, dynamic and local talent supply that can deliver value to the company's clients in the region and elsewhere. Cognizant's new office houses a state-of-the-art training facility for new and experienced hires. About Cognizant Cognizant (NASDAQ: CTSH) is a leading provider of information technology, consulting, and business process services, dedicated to helping the world's leading companies build stronger businesses. Headquartered in Teaneck, New Jersey (U.S.), Cognizant combines a passion for client satisfaction, technology innovation, deep industry and business process expertise, and a global, collaborative workforce that embodies the future of work. With over 100 development and delivery centers worldwide and approximately 255,800 employees as of September 30, 2016, Cognizant is a member of the NASDAQ-100, the S&P 500, the Forbes Global 2000, and the Fortune 500 and is ranked among the top performing and fastest growing companies in the world. Visit us online at www.cognizant.com or follow us on Twitter: Cognizant.

News Article | December 2, 2015
Site: www.nature.com

As former chairman of Pakistan's Higher Education Commission and former coordinator-general of the Organisation of Islamic Cooperation's science and technology body COMSTECH, I suggest that some universities in the Muslim world are not in such dire need of revitalization as Nidhal Guessoum and Athar Osama imply (Nature 526, 634–636; 2015). At least 3 such institutions are ranked in the world's top 250 — the University of Malaya in Kuala Lumpur, and King Fahd University and King Saud University, both in Saudi Arabia (see go.nature.com/4gfu2u). In 2013 and 2014, the Middle East Technical University, Istanbul Technical University and Bilkent University in Turkey were ranked in the top 400 globally (see go.nature.com/m6195d). Pakistan's National University of Sciences and Technology and the Pakistan Institute of Engineering and Applied Sciences were ranked in the top 200 Asian universities in 2014 (see go.nature.com/kdwt8w). The King Abdullah University of Science and Technology in Saudi Arabia and the Masdar Institute in Abu Dhabi are rising stars. According to 2014 data on scientific publications, Iran ranks 16th in the world, Turkey is 19th and Malaysia is 23rd — on a par with Switzerland, Taiwan and some Scandinavian countries, and ahead of South Africa (see go.nature.com/ms6fct). Furthermore, the requirements of the United Arab Emirates' Commission of Academic Accreditation (CAA) are more stringent than those of the US Accreditation Board for Engineering and Technology (ABET), for instance. Whereas the CAA requires faculty members to have the highest degree in their field (such as a PhD), ABET requires only appropriate qualifications. The CAA also requires universities to have accredited PhD programmes in addition to accredited bachelor's and master's degrees.

Nafady A.,Monash University | Nafady A.,King Saud University | O'Mullane A.P.,RMIT University | Bond A.M.,Monash University
Coordination Chemistry Reviews | Year: 2014

TCNQ- radical anions (TCNQ=7,7,8,8,-tetracyanoquinodimethane) form a wide range of semiconducting coordination polymers when coordinated to transition metals. Some materials such as CuTCNQ and AgTCNQ exhibit molecular switching and memory storage properties; others have intriguing magnetic properties and for example may behave as molecular magnets at low temperature. In this review, the electro- and photo-chemical synthesis and characterization of this important class of material is reviewed. In particular, the electrochemistry and the redox properties of TCNQ derivatives of coordination polymers based on Cu, Ag, Mn, Fe, Co, Ni, Zn and Cd transition metals are surveyed, with an emphasis on the mechanistic aspects of their electrochemical formation via nucleation-growth processes. Given that TCNQ is an extremely good electron acceptor, readily forming TCNQ- and TCNQ2-, electrochemical reduction of TCNQ in the presence of a transition metal ion provides an ideal method for synthesis of metal-TCNQ materials by electrocrystallization from organic solvents and ionic liquids or solid-solid transformation using TCNQ modified electrodes from aqueous media containing transition metal electrolytes. The significance of the reversible formal potential (E0f) in these studies is discussed. The coupling of electrocrystallization on electrode surfaces and microscopic characterization of the electrodeposited materials reveals a wide range of morphologies and phases which strongly influence their properties and applications. Since TCNQ can also be photo-reduced in the presence of suitable electron donors, analogous photochemical approaches to the synthesis of TCNQ-transition metal derivatives are available. The advantages of electrochemical and photochemical methods of synthesis relative to chemical synthesis are outlined. © 2014 Elsevier B.V.

Li W.,Fudan University | Wu Z.,Monash University | Wang J.,Fudan University | Elzatahry A.A.,King Saud University | And 2 more authors.
Chemistry of Materials | Year: 2014

Mesoporous TiO2 has gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. In this Perspective, we summarize the significant advances on the synthesis of mesoporous TiO2 in terms of rationally controlling the hydrolysis and condensation rates of titanium precursors to enable the cooperative assembly and/or successful infiltration via the templating methods. The rational designs and fundamentals for preparing mesoporous TiO2 are presented in the context of improving the conversion efficiencies of solar energy (e.g., maximizing the UV and/or visible light adsorption, minimizing the recombination of photogenerated electron-hole pairs, and optimizing the mass and charge transport) and enhancing the performances of lithium-ion batteries. New trends and ongoing challenges in this field are also highlighted and proposed. © 2013 American Chemical Society.

Sallam R.M.,King Saud University | Sallam R.M.,Ain Shams University
Disease Markers | Year: 2015

With the introduction of recent high-throughput technologies to various fields of science and medicine, it is becoming clear that obtaining large amounts of data is no longer a problem in modern research laboratories. However, coherent study designs, optimal conditions for obtaining high-quality data, and compelling interpretation, in accordance with the evidence-based systems biology, are critical factors in ensuring the emergence of good science out of these recent technologies. This review focuses on the proteomics field and its new perspectives on cancer research. Cornerstone publications that have tremendously helped scientists and clinicians to better understand cancer pathogenesis; to discover novel diagnostic and/or prognostic biomarkers; and to suggest novel therapeutic targets will be presented. The author of this review aims at presenting some of the relevant literature data that helped as a step forward in bridging the gap between bench work results and bedside potentials. Undeniably, this review cannot include all the work that is being produced by expert research groups all over the world. © 2015 Reem M. Sallam.

Alothman Z.A.,King Saud University | Apblett A.W.,Oklahoma State University
Journal of Hazardous Materials | Year: 2010

Mesoporous silicas carrying di-, tri-, or penta-amine functional groups were prepared by prior functionalization of a mesoporous silica with bromopropyl-functional groups followed by nucleophilic displacement of the bromine atoms by ethylenediamine, diethylenetriamine, or tetraethylenepentamine, respectively. A synthetic method was developed that gave a starting material with very high surface coverage by the 3-brompropyl groups. Batch tests were conducted to investigate the capabilities of the prepared adsorbents for the removal of copper, zinc, and cadmium from aqueous solutions. The metal adsorption capacities for these metals were determined as a function of the polyamine group used and the total nitrogen content. The tendency to chemisorb divalent metal ions was found to follow the order: Cu2+>Zn2+>Cd2+. It was found that the ethylenediamine derivative unexpectedly exhibited the highest capacities. The metal sorption by the ethylenediamine functionalized silica was found to follow first order kinetics with rate constants for Cu2+, Zn2+ and Cd2+ uptake of 0.028, 0.019, and 0.014min-1, respectively. The substituted mesoporous silicas showed high resistance to leaching of the grafted polyamine groups. Copper ions that were adsorbed at the surface of the mesoporous silicas can be recovered by washing with an aqueous solution of 1.0M HNO3. The activities of the recovered mesoporous silicas were between 80 and 90% of the original materials. © 2010 Elsevier B.V.

Pignolo R.J.,University of Pennsylvania | Kassem M.,University of Southern Denmark | Kassem M.,King Saud University
Journal of Bone and Mineral Research | Year: 2011

The aim of this review is to provide a critical reading of recent literature pertaining to the presence of circulating, fluid-phase osteoblastic cells and their possible contribution to bone formation. We have termed this group of cells collectively as circulating osteogenic precursor (COP) cells. We present evidence for their existence, methods used for their isolation and identification, possible physiological and pathophysiological roles, cellular origins, and possible mechanisms for their migration to target tissues. Copyright © 2011 American Society for Bone and Mineral Research.

Mostafa G.A.,Ain Shams University | Mostafa G.A.,King Saud University | Al-Ayadhi L.Y.,King Saud University
Journal of Neuroimmunology | Year: 2013

Etiology of autism has become an area of a significant controversy. Allergy induced autism is an area of research wherein immune responses to some allergens may play a pathogenic role in autism. Allergy may induce the production of brain specific auto-antibodies in a subgroup of autistic children. We are the first to investigate the possible link between allergic manifestations and serum levels of both anti-myelin basic protein (anti-MBP) and anti-myelin associated glycoprotein (anti-MAG) brain-specific auto-antibodies, which were measured by ELISA method, in 42 autistic children in comparison to 42 healthy-matched children. Allergic manifestations (bronchial asthma, atopic dermatitis and/or allergic rhinitis) were found in 47.6% of autistic patients. Increased serum levels of anti-MBP and anti-MAG auto-antibodies were found in 57.1% and 66.7%, respectively of autistic children. In addition, 78.5% of autistic children had increased serum levels of both anti-MBP and/or anti-MAG auto-antibodies. Autistic patients with allergic manifestations had significantly higher serum levels of anti-MBP and anti-MAG auto-antibodies than those without these manifestations (P. <. 0.001 and P. = .0.001, respectively). In conclusion, allergy may be a contributing factor to the increased serum levels of anti-MBP and anti-MAG auto-antibodies in some autistic children. Indeed, we need to know more about the links between allergy, immune system and brain in autism for finding new therapeutic modalities in autism. © 2013 Elsevier B.V.

Lelieveld J.,Max Planck Institute for Chemistry | Lelieveld J.,Cyprus Institute | Evans J.S.,Harvard University | Evans J.S.,Cyprus University of Technology | And 3 more authors.
Nature | Year: 2015

Assessment of the global burden of disease is based on epidemiological cohort studies that connect premature mortality to a wide range of causes, including the long-term health impacts of ozone and fine particulate matter with a diameter smaller than 2.5 micrometres (PM2.5). It has proved difficult to quantify premature mortality related to air pollution, notably in regions where air quality is not monitored, and also because the toxicity of particles from various sources may vary. Here we use a global atmospheric chemistry model to investigate the link between premature mortality and seven emission source categories in urban and rural environments. In accord with the global burden of disease for 2010 (ref. 5), we calculate that outdoor air pollution, mostly by PM2.5, leads to 3.3 (95 per cent confidence interval 1.61-4.81) million premature deaths per year worldwide, predominantly in Asia. We primarily assume that all particles are equally toxic, but also include a sensitivity study that accounts for differential toxicity. We find that emissions from residential energy use such as heating and cooking, prevalent in India and China, have the largest impact on premature mortality globally, being even more dominant if carbonaceous particles are assumed to be most toxic. Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity. Model projections based on a business-as-usual emission scenario indicate that the contribution of outdoor air pollution to premature mortality could double by 2050. ©2015 Macmillan Publishers Limited. All rights reserved.

News Article | January 25, 2016
Site: www.scientificcomputing.com

Carnivorous plants, such as the Venus flytrap, depend on meals of insects to survive in nutrient-poor soil. They sense the arrival of juicy insects, lured by the plants' fruity scent, with the aid of sensitive trigger hairs on the inner surfaces of their traps. Researchers have looked more closely at exactly how the plants decide when to keep their traps shut and begin producing their acidic, prey-decomposing cocktail of enzymes. The short answer is: they count. "The carnivorous plant Dionaea muscipula, also known as Venus flytrap, can count how often it has been touched by an insect visiting its capture organ in order to trap and consume the animal prey," says Rainer Hedrich of Universität Würzburg in Germany. To find out whether Venus flytraps record touches, in the new study, reported in the Cell Press journal Current Biology on January 21, 2016, Hedrich and his colleagues fooled the plants into thinking they'd landed an insect by applying increasing numbers of mechano-electric stimuli to their trap and monitoring their responses. The studies show that a single touch to the trigger hair is enough to generate a response, setting the trap into a "ready-to-go" mode. In other words, the plants make note but don't snap just yet. It might be a false alarm, after all. With the second stroke, the trap closes around the prey to form what Hedrich and his colleagues liken to a green stomach. As the prey attempt to escape, they wind up touching the mechano-sensitive trigger hairs again and again, which only serves to excite the plant further. At this stage, the plant begins to produce a special touch hormone. After five triggers, glands on the inner surface of the trap also produce digestive enzymes and transporters to take up nutrients. Hedrich calls it a "deadly spiral of capture and disintegration." This input also allows the plant to scale its production of costly ingredients to the size of the meal. "The number of action potentials informs [the plant] about the size and nutrient content of the struggling prey," Hedrich said. "This allows the Venus flytrap to balance the cost and benefit of hunting." Interestingly, the plants show a particularly marked increase in production of a transporter that allows them to take up sodium. It's not clear exactly what the salt does for the plant, but the researchers suggest that it may have something to do with how Venus flytraps maintain the right balance of water inside their cell walls. Hedrich and his colleagues are now sequencing the Venus flytrap genome. In those sequences, they expect to find additional clues about the plants' sensory systems and chemistry needed to support a carnivorous lifestyle and about how those traits have evolved over time. This work was supported by the European Research Council; MINECO; the International Research Group Program; the Deanship of Scientific Research, King Saud University; the Australian Research Council; and the Grain Research and Development Corporation. Citation: Current Biology, Böhm and Scherzer et al.: "The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake" http://dx.doi.org/10.1016/j.cub.2015.11.057

Al-Saleh I.,King Faisal Specialist Hospital And Research Center | Al-Sedairi A.A.,King Saud University
Science of the Total Environment | Year: 2011

The risks and benefits of using mercury (Hg) in dental amalgam have long been debated. This study was designed to estimate Hg body burden and its association with dental amalgam fillings in 182 children (ages: 5-15. years) living in Taif City. Hg was measured in urine (UHg), hair (HHg) and toenails (NHg) by the Atomic Absorption Spectrophotometer with Vapor Generator Accessory system. Urinary Hg levels were calculated as both micrograms per gram creatinine (μg/g creatinine) and micrograms per liter (μg/L). We found that children with amalgam fillings (N=106) had significantly higher UHg-C levels than children without (N=76), with means of 3.763μg/g creatinine versus 3.457μg/g creatinine, respectively (P=0.019). The results were similar for UHg (P=0.01). A similar pattern was also seen for HHg, with means of 0.614μg/g (N=97) for children with amalgam versus 0.242μg/g (N=74) for those without amalgam fillings (P=0). Although the mean NHg was higher in children without amalgam (0.222μg/g, N=61) versus those with (0.163μg/g, N=101), the relationship was not significant (P=0.069). After adjusting for many confounders, the multiple logistic regression model revealed that the levels of UHg-C and HHg were 2.047 and 5.396 times higher, respectively, in children with dental amalgam compared to those without (P<0.01). In contrast, a significant inverse relationship was seen between NHg levels and dental amalgam fillings (P=0.003). Despite the controversy surrounding the health impact of dental amalgam, this study showed some evidence that amalgam-associated Hg exposure might be related with symptoms of oral health, such as aphthous ulcer, white patches, and a burning-mouth sensation. Further studies are needed to reproduce these findings. The present study showed that significant numbers of children with or without amalgam had Hg levels exceeding the acceptable reference limits. The detrimental neurobehavioral and/or nephrotoxic effects of such an increased Hg on children should be a cause of concern, and further investigation is warranted. Our results are alarming and indicate an urgent need for biomonitoring and assessment of exposure. Changes in dental practices involving amalgam, especially for children, are highly recommended in order to avoid unnecessary exposure to Hg. © 2011 Elsevier B.V.

Badr G.,King Saud University | Badr G.,Assiut University
Lipids in Health and Disease | Year: 2013

Background: Delayed wound healing is considered one of the most serious diabetes-associated complications. The presence of replicating organisms such as bacteria within a diabetic's wound is considered one of the most important factors that impair cutaneous wound healing and the potential cellular and/or molecular mechanisms that are involved in the healing process. Defensins, which are anti-microbial peptides, have potent bactericidal activity against a wide spectrum of the bacterial and fungal organisms that are commonly responsible for wound infections. We recently demonstrated that camel whey proteins (WPs) expedite the healing of diabetic wounds by enhancing the immune response of wounded tissue cells and by alleviating some of the diabetic complications. Methods. In the present study, we investigated the effects of WP supplementation on the mRNA and protein expression levels of β-defensin-1 (BD-1), 2 and 3 and subsequently on the wound healing process in a streptozotocin (STZ)-induced diabetic mouse model. In this study, three groups of mice were used (10 mice per group): group 1, the non-diabetic mice (control); group 2, the diabetic mice; and group 3, the diabetic mice that received a daily supplement of undenatured WP (100 mg/kg of body weight) via oral gavage for 1 month. Results: Compared with the non-diabetic control mice, the diabetic mice exhibited delayed wound closure that was characterized by a reduction in hydroxyproline content (indicator of collagen deposition), a marked elevation in free radical levels and a prolonged elevation in the levels of inflammatory cytokines, including interleukin-6 (IL-6), transforming growth factor-beta (TGF-β) and tumor necrosis factor-alpha (TNF-α). Interestingly, compared with the diabetic mice that did not receive WP supplementation, the diabetic mice with WP had an accelerated closure and healing process of their wounds. The WP supplementation also decreased their levels of free radicals and restored their hydroxyproline content; proinflammatory cytokine levels; and expression of BD-1, 2 and 3 in the wounded tissue. Conclusion: WP supplementation may be beneficial for improving the healing and closure of diabetic wounds. © 2013 Badr; licensee BioMed Central Ltd.

Sherif E.-S.M.,King Saud University | Erasmus R.M.,University of Witwatersrand | Comins J.D.,University of Witwatersrand
Electrochimica Acta | Year: 2010

The corrosion of single crystal pure iron in 3.5% NaCl solutions and its inhibition by 3-amino-5-mercapto-1,2,4-triazole (AMTA) have been studied using in situ and ex situ Raman spectroscopy, cyclic voltammetry (CV), open-circuit potential (OCP), potentiodynamic polarization (PDP), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) measurements. CV experiments indicated that the iron electrode in the chloride solution alone showed an anodic peak at ∼-650 mV after the 5th cycle shifted to ∼-610 mV after the 20th cycle; another cathodic peak appeared at ∼-990 mV. In the presence of 1.0 mM AMTA, these two peaks shifted to ∼550 and -1050 mV, respectively. OCP, PDP, CA and EIS revealed that the presence of AMTA and the increase of its concentration move the corrosion potential to more positive values and decrease both the corrosion current and corrosion rate. This effect also increases with increasing the immersion time of iron electrode to 24 h in the test electrolyte. In situ and ex situ Raman investigations confirmed that the addition of AMTA molecules to the chloride solution strongly inhibits the iron corrosion through their adsorption onto the surface blocking its active sites and preventing its corrosion. © 2010 Elsevier Ltd. All rights reserved.

Long and persistent uncontrolled diabetes tends to degenerate the immune system and increase the incidence of infections in diabetic patients. A serious complication of diabetes is impaired healing, which diminishes physical activity and, in some cases, leads to chronic wounds and limb amputation. Whey proteins (WPs) enhance immunity during early development and have a protective role in some immune disorders. The effect of camel WPs on wound healing in a streptozotocin-induced type 1 diabetic mice model was investigated. Sixty male mice were equally distributed into 3 experimental groups: group 1, non-diabetic control mice; group 2, diabetic mice; and group 3, diabetic mice that were orally supplemented with undenatured WP (100 mg/kg body weight/day for 1 month through oral gavage). We observed that the diabetic mice exhibited delayed wound closure characterized by a significant reduction in collagen deposition, prolonged elevation in inflammatory cytokines, aberrant activation of STAT3 and reduction in the activation of Akt and NF-κB when compared with the control mice. Moreover, in the diabetic mice, the wound-resident macrophages were dysfunctional and demonstrated increased apoptosis, a significant reduction in their phagocytotic ability, aberrant activation of STAT3 and a marked reduction in the activation of Akt. Interestingly, the supplementation of diabetic mice with WP significantly enhanced the collagen deposition, limited the inflammatory stimuli, restored the activation of STAT3, Akt and NF-κB and greatly improved the closure of diabetic wounds compared with the control mice. Most important, the supplementation of diabetic mice with WP rescued functional, long-lived wound-resident macrophages. Our data reveal the benefits of WP supplementation in improving the healing and closure of diabetic wounds. Copyright © 2012 S. Karger AG, Basel.

Beyenbach K.W.,Cornell University | Skaer H.,University of Cambridge | Dow J.A.T.,University of Glasgow | Dow J.A.T.,King Saud University
Annual Review of Entomology | Year: 2010

Molecular biology is reaching new depths in our understanding of the development and physiology of Malpighian tubules. In Diptera, Malpighian tubules derive from ectodermal cells that evaginate from the primitive hindgut and subsequently undergo a sequence of orderly events that culminates in an active excretory organ by the time the larva takes its first meal. Thereafter, the tubules enlarge by cell growth. Just as modern experimental strategies have illuminated the development of tubules, genomic, transcriptomic, and proteomic studies have uncovered new tubule functions that serve immune defenses and the breakdown and renal clearance of toxic substances. Moreover, genes associated with specific diseases in humans are also found in flies, some of which, astonishingly, express similar pathophenotypes. However, classical experimental approaches continue to show their worth by distinguishing between-omic possibilities and physiological reality while providing further detail about the rapid regulation of the transport pathway through septate junctions and the reversible assembly of proton pumps. © 2010 by Annual Reviews All rights reserved.

Azer S.A.,King Saud University | Guerrero A.P.S.,University of Hawai | Walsh A.,McMaster University
Medical Teacher | Year: 2013

Background: In an integrated curriculum such as problem-based learning (PBL), students need to develop a number of learning skills and competencies. These cannot be achieved through memorization of factual knowledge but rather through the development of a wide range of cognitive and noncognitive skills that enhance deep learning. Aim: The aim of this article is to provide students and teachers with learning approaches and learning strategies that enhance deep learning. Methods: We reviewed current literature in this area, explored current theories of learning, and used our experience with medical students in a number of universities to develop these tips. Results: Incorporating the methods described, we have developed 12 tips and organized them under three themes. These tips are (1) learn how to ask good questions, (2) use analogy, (3) construct mechanisms and concept maps, (4) join a peer-tutoring group, (5) develop critical thinking skills, (6) use self-reflection, (7) use appropriate range of learning resources, (8) ask for feedback, (9) apply knowledge learnt to new problems, (10) practice learning by using simulation, (11) learn by doing and service learning, and (12) learn from patients. Conclusions: Practicing each of these approaches by students and teachers and applying them in day-to-day learning/teaching activities are recommended for optimum performance. © 2013 Informa UK Ltd.

Zhang Y.,University of Hong Kong | Crous P.W.,Fungal Biodiversity Center | Schoch C.L.,U.S. National Center for Biotechnology Information | Hyde K.D.,Mae Fah Luang University | Hyde K.D.,King Saud University
Fungal Diversity | Year: 2012

One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae. © 2011 The Author(s).

Khan M.A.,King Saud University | Ho Y.-S.,Asia University, Taiwan
Science of the Total Environment | Year: 2012

The purpose of this study was to identify the top-cited articles published in environmental science journals listed in Journal Citation Reports (JCR). The Web of Science database was used to retrieve the top-cited articles having 500 or more total citations from their publication to 2010. The articles were analyzed with regard to institution and country of origin with five indicators including total number of top-cited articles, as well as independent, collaborative, first author, and corresponding author articles. Article life was also investigated for history of impact of articles. Results showed that 88 articles were cited more than 500 times. These articles appeared in 26 different journals, with 28% of all top-cited articles in Environmental Science & Technology, followed by Water Resources Research. The top-cited articles published since 1971 to 2002 were from 17 countries. The USA published the most of the articles and was ranked on top among the five indicators. The U.S. Geological Survey was the most productive institution while, the Brunel University, UK published the most inter-institutionally collaborative and corresponding author articles under environmental science category. © 2012 Elsevier B.V..

King Saud University and King Faisal Specialist Hospital And Research Center | Date: 2016-03-16

The present invention relates to benzo-thiazolo-imidazole compounds and their uses. Moreover, the present invention relates to pharmaceutical compositions comprising such a benzo-thiazolo-imidazole compound. Furthermore, the present invention relates to the use of such a benzo-thiazolo-imidazole compound for the manipulation of cultured cells.

The present invention relates to benzo-thiazolo-imidazole compounds and their uses. Moreover, the present invention relates to pharmaceutical compositions comprising such a benzo-thiazolo-imidazole compound. Furthermore, the present invention relates to the use of such a benzo-thiazolo-imidazole compound for the manipulation of cultured cells.

Via G.,Cardiac Guard | Via G.,University of Witwatersrand | Via G.,King Saud University | Via G.,Mount Sinai School of Medicine
Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography | Year: 2014

BACKGROUND: Focused cardiac ultrasound (FoCUS) is a simplified, clinician-performed application of echocardiography that is rapidly expanding in use, especially in emergency and critical care medicine. Performed by appropriately trained clinicians, typically not cardiologists, FoCUS ascertains the essential information needed in critical scenarios for time-sensitive clinical decision making. A need exists for quality evidence-based review and clinical recommendations on its use.METHODS: The World Interactive Network Focused on Critical UltraSound conducted an international, multispecialty, evidence-based, methodologically rigorous consensus process on FoCUS. Thirty-three experts from 16 countries were involved. A systematic multiple-database, double-track literature search (January 1980 to September 2013) was performed. The Grading of Recommendation, Assessment, Development and Evaluation method was used to determine the quality of available evidence and subsequent development of the recommendations. Evidence-based panel judgment and consensus was collected and analyzed by means of the RAND appropriateness method.RESULTS: During four conferences (in New Delhi, Milan, Boston, and Barcelona), 108 statements were elaborated and discussed. Face-to-face debates were held in two rounds using the modified Delphi technique. Disagreement occurred for 10 statements. Weak or conditional recommendations were made for two statements and strong or very strong recommendations for 96. These recommendations delineate the nature, applications, technique, potential benefits, clinical integration, education, and certification principles for FoCUS, both for adults and pediatric patients.CONCLUSIONS: This document presents the results of the first International Conference on FoCUS. For the first time, evidence-based clinical recommendations comprehensively address this branch of point-of-care ultrasound, providing a framework for FoCUS to standardize its application in different clinical settings around the world. Copyright © 2014. Published by Mosby, Inc.

Javed F.,King Saud University | Romanos G.E.,State University of New York at Stony Brook
Photomedicine and Laser Surgery | Year: 2013

Objective: The aim of this study was to assess whether or not photodynamic therapy enhanced standard antibacterial therapy in dentistry. Background data: Photodynamic therapy when used as an adjunct to conventional periodontal therapy kills more bacteria than when conventional periodontal therapy is used alone. Materials and methods: To address the focused question, "Does photodynamic therapy enhance killing of oral bacteria?" PubMed/MEDLINE® and Google Scholar databases were explored. Original human and experimental studies and studies using photodynamic therapy for killing oral bacteria were included. Letters to the Editor, historic reviews, and unpublished data were excluded. Results: Photodynamic therapy significantly reduces periodontopathogenic bacteria including Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Porphyromonas gingivalis. Photodynamic therapy kills cariogenic bacteria (such as Streptococcus mutans and Streptococcus sanguis), bacteria associated with infected root canals, and those associated with periimplantitis. Conclusions: Photodynamic therapy, when used as an adjunct to conventional oral disinfection protocols, enhances standard antibacterial therapy in dentistry. © Mary Ann Liebert, Inc.

Romanos G.E.,State University of New York at Stony Brook | Javed F.,King Saud University
Journal of Oral Rehabilitation | Year: 2014

The aim was to assess the role of platform switching (PS) in minimising crestal bone loss around dental implants through a systematic review of the currently available clinical evidence. To address the focused question 'Does PS minimise crestal bone loss compared with non-platform-switched (NPS) implants?', PubMed/Medline and Google Scholar databases were explored from 1986 up to and including December 2013 using the following key words in different combinations: 'bone loss', 'dental implant', 'diameter', 'mandible', 'maxilla' and 'platform switching'. Letters to the Editor, unpublished data, historical reviews, case reports and articles published in languages other than English were excluded. Fifteen clinical studies were included. In seven studies, PS and NPS implants were placed in both the maxilla and mandible. In 13 studies, implants were placed at crestal bone levels whereas in one study, implants were placed supracrestally. Three studies reported the bucco-lingual (or transversal) width of the alveolar ridge which ranged between 7-8 mm. Seven studies reported that implants placed according to the PS concept did not minimise crestal bone loss as compared with NPS implants. 3D-Implant positioning, width of alveolar ridge and control of micromotion at the implant-abutment interface are the more critical factors that influence crestal bone levels than PS. © 2014 John Wiley & Sons Ltd.

Dyab A.K.F.,Minia University | Atta A.M.,King Saud University
RSC Advances | Year: 2013

Non-aqueous emulsions with a high storage stability are stabilised with organic solvent-borne crosslinked poly(N-isopropylacrylamide-co-2-acrylamido-2- methylpropane sulfonic acid) poly(NIPAM-co-AMPS) microgels functionalised with a nonionic polymerisable surfactant (polyoxyethylene 4-nonyl-2-propyl-phenyl maleate ester). The oil-oil interfacial tensions are reduced to unprecedented values by the newly prepared microgels. © 2013 The Royal Society of Chemistry.

Background: While it is known that advanced age alters the recruitment of neutrophils during wound healing, thereby delaying the wound healing process, little is known about prolonged wound healing in advanced ages. Thus, we investigated the correlation of neutrophil recruitment with healing events, and the impact of whey protein (WP) on neutrophil activation.Methods: The animals were allocated into wounded young group, wounded older group and wounded older rats with daily treatment of WP at a dose of 100 mg/kg of body weight.Results: Our results pointed to a marked deficiency in the number of neutrophils in the wounds of older rats, which was accompanied with impairment of the healing process. In the group of older rats, phagocytic activity, as tested by fluorescence microscopy, declined throughout the first 24 hours after wounding. Both the neutrophil number and the phagocytic activity recovered in older rats which received WP supplementation. Interestingly, WP was found to significantly up-regulate the MIP-1α and CINC-1 mRNA expression in old rats. On the other hand, the wound size in older rats was significantly higher than that in younger ones. Blood angiogenesis was also significantly delayed in the older group as opposed to the young rats. WP, however, was found to return these indices to normal levels in the older rats. Proliferation and epidermal migration of the keratinocytes and the collagen deposition were also returned to the normal rates.Conclusions: This data confirms the critical role of neutrophil recruitment in the early inflammatory phase of wound healing in older rats. In addition, WP protein was used to improve neutrophil function in older rats, healing events returned to a more normal profile. © 2014 Ebaid; licensee BioMed Central Ltd.

Ebaid H.,King Saud University | Ebaid H.,Minia University
Nutrition and Metabolism | Year: 2014

T cell mediated autoimmune diabetes is characterized by immune cell infiltration of pancreatic islets and destruction of insulin-producing β-cells. This study was designed to assess the effect of whey proteins (WP) on the responsiveness of lymphocytes in rats after four months of Streptozotocin (STZ)-induced Type 1 diabetes (T1D). A diabetic group was supplemented with WP daily for five weeks at a dose of 100 mg/kg. Ribonucleic acid (RNA) was extracted from stimulated lymphocytes in order to analyse gene expressions using real time PCR and RT-PCR. PCR results were confirmed with ELISA. The proliferation capacity of lymphocytes and their homing to the spleen were studied. Antigen-activated lymphocytes showed that diabetes impaired the mRNA expression of the protein kinase B (Akt1), Cdc42, and the co-stimulatory molecule, CD28, which are important for cell survival, actin polymerization and T cell activation, respectively. Accordingly, proliferation of lymphocytes was found to be suppressed in diabetic rats, both in vivo and in vitro. WP was found to restore Akt1, Cdc42 and CD28 mRNA expression during diabetes to normal levels. WP, therefore, served to activate the proliferation of B lymphocytes in diabetic rats both in vivo and in vitro. Although WP was found to up-regulate mRNA expression of both interleukin (IL)-2 and interferon gamma (IFN-γ), it suppressed the proliferation activity of almost all T cell subsets. This was confirmed by WP normalizing the structure and function of ß cells. Meanwhile, WP was found to down regulate the mRNA expression of Tumor necrosis factor-alpha (TNF-α) and its programmed cell death-receptor (Fas). Taken together, the results of this study provide evidence for the potential impact of WP in the treatment of immune impairment in T1D, suggesting that it serves to reverse autoimmunity by suppressing autoreactive T cells and down regulating TNF-α and Fas, resulting in improved pancreatic ß cell structure and function. © 2014 Ebaid; licensee BioMed Central Ltd.

Aljada A.,King Saud bin Abdulaziz University for Health Sciences | Mousa S.A.,Albany College of Pharmacy and Health Sciences | Mousa S.A.,King Saud University
Pharmacology and Therapeutics | Year: 2012

Abstract Metformin has been shown to exert anti-neoplastic and chemopreventive activities in epidemiological and animal studies. This review article discusses the epidemiological studies and examines the possible mechanisms by which metformin exerts its anti-carcinogenic activities in breast, colon, ovarian, lung, and prostate cancers. We performed a systematic review of the clinical studies examining the anti-neoplastic activities of metformin and the potential mechanisms associated with these activities. Several observational and biological studies revealed a significant association between metformin and reduction in cancer incidence. The mechanisms by which metformin exerts these effects are unknown. This action may be mediated through activation of AMP-activated protein kinase (AMPK), inhibition of the mammalian target of rapamycin (mTOR) pathway, and inhibition of insulin like growth factors (IGFs), and many others. Further laboratory investigation and large, prospective population clinical trials are required to elucidate metformin anti-neoplastic and chemo-preventive actions. © 2011 Elsevier Inc. All rights reserved.

Nowilaty S.R.,King Khaled Eye Specialist Hospital | Mousa A.,King Saud University | Ghazi N.G.,King Khaled Eye Specialist Hospital
Ophthalmology | Year: 2013

Purpose: To report and analyze the spectral-domain optical coherence tomography (SD-OCT) features of the posterior pole and papillomacular fold (PMF) in posterior microphthalmos (PM) in relation to axial length of the globe and corneal power. Design: Comparative case series. Participants: Forty eyes of 20 PM patients and 70 eyes of 35 age-matched controls. Methods: All PM and control eyes underwent a full biometric evaluation, including axial length and corneal power measurements, and macular SD-OCT. In addition, a novel SD-OCT marker of the posterior pole curvature, termed the posterior pole curvature index (PPCI), was measured along both the vertical and horizontal meridians. The OCT characteristics of the PMF were analyzed and the PPCIs were compared and correlated with the axial length and corneal power in both groups of eyes, and with the PMF severity in PM eyes. Main Outcome Measures: We considered the SD-OCT features of the PMF, the PPCI in PM eyes and controls, and the correlations between PPCI and PMF severity and axial length. Results: All PMFs were predominantly horizontal and partial thickness, sparing the outer retina except the outer plexiform layer. The PPCI in PM eyes (mean ± standard deviation, 145±40.3 microns; median, 144) was significantly larger than that of controls (14±12.8 microns; median, 14; P<0.0001). In addition, the vertical PPCI in PM eyes, but not in controls, was notably larger than the horizontal PPCI (mean difference, 55±30.4 microns; P<0.0001). In PM eyes, the PPCI strongly correlated with PMF height (R = 0.68; P<0.0001), inverse axial length (R = -0.71; P<0.0001), and corneal power (R = 0.49; P = 0.002), and the PMF height correlated strongly and inversely with the axial length (R = -0.62; P<0.0001). Conclusions: The PMF in PM eyes has characteristic morphologic SD-OCT features. The increased posterior pole curvature in PM and its significant correlation with the axial length, the PMF severity and keratometry established in this study suggest that PM eyes are not only shorter than normal, but seem to be abnormally shaped posteriorly, particularly along the vertical meridian. This factor may play a role in the pathogenesis and morphology of the PMF. © 2013 by the American Academy of Ophthalmology Published by Elsevier Inc.

Ramadan M.F.,Zagazig University | Al-Ghamdi A.,King Saud University | Al-Ghamdi A.,King College
Journal of Functional Foods | Year: 2012

Royal jelly (RJ) is an important functional food item that possess several health promoting properties. It has been widely used in commercial medical products, healthy foods and cosmetics in many countries. RJ has been demonstrated to possess numerous functional properties such as antibacterial activity, anti-inflammatory activity, vasodilative and hypotensive activities, disinfectant action, antioxidant activity, antihypercholesterolemic activity and antitumor activity. Biological activities of RJ are mainly attributed to the bioactive fatty acids, proteins and phenolic compounds. In consideration of potential utilisation, detailed knowledge on the composition of RJ is of major importance. The diversity of applications to which RJ can be put gives this novel food great industrial importance. This review summarises the composition, nutritional value and functional properties of RJ. © 2011 Elsevier Ltd.

Dyab A.K.F.,Minia University | Dyab A.K.F.,King Saud University
Macromolecular Chemistry and Physics | Year: 2012

Various polymeric materials based on simple, double, and triple emulsions stabilized solely by dichlorodimethylsilane (DCDMS)-modified amorphous silica nanoparticles of well-controlled surface hydrophobicities or organo-modified Laponite clay nanoparticles are described. Magnetic and fluorescent polymer beads having different morphologies are fabricated from double-emulsion templates. Polymer foams based on Pickering emulsions are fabricated and functionalized using different materials such as sporopollenin and zinc metal particles. Suspension polymerization of both oil phases of a novel Pickering triple emulsion results in the formation of new porous hierarchical structures. Polymer foams and beads based on novel nonaqueous Pickering simple and double emulsions are fabricated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rezk H.,Minia University | Eltamaly A.M.,King Saud University | Eltamaly A.M.,Mansoura University
Solar Energy | Year: 2015

This paper aimed to study the behavior of different maximum power point tracking (MPPT) techniques applied to PV systems. In this work, techniques such as hill climbing (HC), incremental conductance (INC), perturb-and-observe (P&O), and fuzzy logic controller (FLC) are assessed. A model of PV module and DC/DC boost converter with the different techniques of MPPTs was simulated using PSIM and Simulink software. Co-simulation between PSIM and Simulink software packages is used to establish FLC MPPT technique. The co-simulation is done to take advantage of each program to handle certain part of the system. The response of the different MPPT techniques is evaluated in rapidly changing weather conditions. The results indicate that, FLC performed best among compared MPPT techniques followed by P&O, INC, and, HC MPPT techniques in both dynamic response and steady-state in most of the normal operating range. © 2014 Elsevier Ltd.

A series of 1,3,4-thiadiazole-2(3H)-thiones, 1,3,4-oxadiazole-2(3H)-thiones, 4-amino-1,2,4-triazole-5(4H)-thiones, and substituted hydrazides were tailored and synthesized as new potent inhibitors of tyrosinase. The rationale for inhibitor design was based on the active site structural evidence from the crystal structures of bacterial tyrosinase and potato catechol oxidase enzymes. Kinetic and active site binding studies suggested mono-dentate binding of thiadiazole, oxadiazole, and triazole rings to the active site dicopper center of tyrosinase including hydrophobicity contributing to the potent inhibition. Kinetic plots showed mixed-type of inhibition by all 25 compounds. Substitutions at C3 of the triazole ring and C5 of the thiadiazole/oxadiazole rings were found to be playing a major role in the high binding affinity to tyrosinase. The current work may help develop new potent tyrosinase inhibitors against hyperpigmentation including potential insecticides. © 2010 Elsevier Ltd. All rights reserved.

Omran W.A.,University of Waterloo | Kazerani M.,University of Waterloo | Salama M.M.A.,University of Waterloo | Salama M.M.A.,King Saud University
IEEE Transactions on Energy Conversion | Year: 2011

Photovoltaic (PV) systems are presently allowed to inject into the grid all the power they can generate. However, in the near future, utilities are expected to impose additional regulations and restrictions on the power being injected by large centralized PV systems because of their possible adverse impacts. One of the main issues associated with large PV systems is the fluctuation of their output power. These fluctuations can negatively impact the performance of the electric networks to which these systemsare connected, especially if the penetration levels of these systems are high. Moreover, the fluctuations in the power of PV systems make it difficult to predict their output, and thus, to consider them when scheduling the generating units in the network. The main objective of this paper is to investigate some methods that can be used to reduce the fluctuations in the power generated from a large customer-owned PV system, in the order of megawatts. This paper focuses on three methods: 1) the use of battery storage systems; 2)the use of dump loads; and 3) curtailment of the generated power by operating the power-conditioning unit of the PV system below the maximum power point. The emphasis in the analysis presented in this paper is on investigating the impacts of implementing these methods on the economical benefits that the PV system owner gains. To estimate the maximum revenues gained by the system owner, an linear programming optimization problem is formulated and solved. Moreover, the effect of varying different parameters of the problem is investigated through sensitivity analysis. © 2010 IEEE.

Zeineldin H.H.,Masdar Institute of Science and Technology | Salama M.M.A.,University of Waterloo | Salama M.M.A.,King Saud University
IEEE Transactions on Industrial Electronics | Year: 2011

Sandia frequency shift (SFS) falls under the active islanding detection methods that rely on frequency drift to detect an islanding condition for inverter-based distributed generation. Active islanding detection methods are commonly tested on constant RLC loads where the load's active power is directly proportional to the square of voltage and is independent on the system frequency. Since the SFS method relies primarily on frequency to detect islanding, the load's active power frequency dependence could have an impact on its performance and the nondetection zone (NDZ). In this paper, the impact of the load's active power frequency dependence on the performance of the SFS method, during an islanding condition, is analyzed. A NDZ model that takes into account the load's frequency dependence parameter is derived mathematically and validated through digital simulation. The results show that the load's frequency dependence has a significant impact on the NDZ of the SFS method and thus is an important factor to consider when designing and testing this method. © 2006 IEEE.

Bharali D.J.,Albany College of Pharmacy and Health Sciences | Mousa S.A.,Albany College of Pharmacy and Health Sciences | Mousa S.A.,King Saud University
Pharmacology and Therapeutics | Year: 2010

The application of nanotechnology to medicine, commonly referred to as 'nanomedicine', has the potential to transform our approach to human health and disease. Research at the nanoscale level affords the opportunity to address some of the most confounding human diseases at the molecular level, with the potential for significant improvements in disease prevention, diagnosis and treatment. Rapid advances and emerging technologies in nanoscale systems, particularly nanoparticles, are having a profound impact on cancer diagnosis, treatment and monitoring. The development of nanoparticulate systems that offer improved chemotherapeutic delivery through increased solubility and sustained retention times is an area of intense focus in nanomedicine. In addition, active targeting of nanoparticles through conjugation of tumor-specific cell surface markers such as tumor-specific antibodies or ligands can enhance the efficacy of nanoparticle drug delivery systems while significantly reducing toxicity. Perhaps some of the most exciting advances in nanomedicine are multifunctional nanoparticulate systems for simultaneous imaging of tumor mass and drug delivery. In a relatively short period of time, nanomedicine has already begun to have a strong presence in the global market. This review provides a comprehensive summary of recent progress in nanomedicine as it relates specifically to nanoparticles and anticancer drug delivery. Research into different nanoprobes for cancer detection/imaging will also be discussed. Lastly, the future of this growing and dynamic field and its potential impact will be discussed. © 2010 Elsevier Inc.

El-Sayed A.K.,King Saud University | Soudki K.,University of Waterloo
Journal of Composites for Construction | Year: 2011

Several codes and design guidelines addressing fiber-reinforced polymer (FRP) bars as primary reinforcement for structural concrete have been recently published worldwide. This reflects the great progress in FRP research area that has been conducted by the research community over the past two decades. Most of these design provisions follow the traditional approach of Vc + Vs for shear design. Nevertheless, both equations of concrete contribution Vc and FRP stirrup contribution Vs to shear strength in these guidelines are different in the manner that they are calculated. In this paper, five methods for FRP shear design, currently used in design practice, were reviewed. These methods include the American Concrete Institute design guide, ACI 440.1R-06; the Canadian Standards Association, CAN/CSA-S806-02; the ISIS Canada design manual, ISIS-M03-07; the British Institution of Structural Engineers guidelines; and the design recommendations of the Japan Society of Civil Engineers. The five methods for shear design prescribed in these guidelines were compared with experimental database obtained from the literature. In addition, the modified compression field theory approach was reviewed and compared with the experimental database. © 2011 ASCE.

Stahl W.,Heinrich Heine University Düsseldorf | Sies H.,Heinrich Heine University Düsseldorf | Sies H.,King Saud University
Molecular Nutrition and Food Research | Year: 2012

Carotenoids are micronutrients present mainly in fruits and vegetables, and they are ingested from these sources with the diet. They exhibit specific antioxidant activity but also influence signaling and gene expression at the cellular level. β-Carotene and lycopene, the colorants of carrots and tomatoes, respectively, are among the most prominent members of this group of lipids, and they are usually the dominating carotenoids in human blood and tissues. Both compounds modulate skin properties when ingested as supplements or as dietary products. There is evidence that they protect the skin against sunburn (solar erythema) by increasing the basal defense against UV light-mediated damage. Their photoprotective efficacy, however, is not comparable to the use of a sunscreen. In vitro data show that also other carotenoids are efficient photoprotectors. Among them are lutein and structurally unusual phenolic polyenes like 3,3′-dihydroxyisorenieratene. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stahl W.,Heinrich Heine University Düsseldorf | Sies H.,Heinrich Heine University Düsseldorf | Sies H.,King Saud University
American Journal of Clinical Nutrition | Year: 2012

Protection against skin damage from sunlight by nutritional means has been examined. Likewise, there has been work on the topical application of phytochemicals to the skin. This review focuses on the nutritional aspect of phytochemicals in humans - ie, the provision of carotenoid micronutrients by dietary means to the skin and their role in protection. Human intervention studies have documented protective effects for β-carotene or for lycopene provided either by a carotenoid-rich diet or by supplementation. In exposed tissues, light induces primary and secondary photooxidative processes. Scavenging of reactive oxygen species is considered to be a mechanism of action underlying the protective activity of carotenoids. However, food comprises a complex mixture of numerous constituents, so that other components may also contribute to the observed activity. Molecules with suitable structures absorb UV light and prevent direct damage of cellular targets. Phytoene and phytofluene are precursor molecules of higher unsaturated carotenoids and occur in various fruit and vegetables. Their absorption spectra cover the UVB and UVA range, respectively, thus potentially contributing to photoprotective effects of carotenoid-rich food. Because of the physiologic turnover time of skin, several weeks are required for protective effects to appear. Photoprotection through individual dietary components such as β-carotene or lycopene in terms of sun protection factor is considerably lower than that achieved by using topical sunscreens. However, an optimal supply of antioxidant micronutrients in the skin increases basal dermal defense against UV irradiation, supports longer-term protection, and contributes to maintenance of skin health and appearance. © 2012 American Society for Nutrition.

Shams El-Dein M.Z.,University of Waterloo | Kazerani M.,University of Waterloo | Salama M.M.A.,University of Waterloo | Salama M.M.A.,King Saud University
IEEE Transactions on Sustainable Energy | Year: 2013

Partial shading of a photovoltaic array is the condition under which different modules in the array experience different irradiance levels due to shading. This difference causes mismatch between the modules, leading to undesirable effects such as reduction in generated power and hot spots. The severity of these effects can be considerably reduced by photovoltaic array reconfiguration. This paper proposes a novel mathematical formulation for the optimal reconfiguration of photovoltaic arrays to minimize partial shading losses. The paper formulates the reconfiguration problem as a mixed integer quadratic programming problem and finds the optimal solution using a branch and bound algorithm. The proposed formulation can be used for an equal or nonequal number of modules per row. Moreover, it can be used for fully reconfigurable or partially reconfigurable arrays. The improvement resulting from the reconfiguration with respect to the existing photovoltaic interconnections is demonstrated by extensive simulation results. © 2010-2012 IEEE.

Louly M.-A.,King Saud University | Dolgui A.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP
International Journal of Production Economics | Year: 2011

This paper deals with component supply planning for assembly systems where several types of components are ordered from external suppliers to produce a single type of finished product. Actual component lead times are often different from those contracted because of random delays. An MRP approach with periodic order quantity (POQ) policy is used for the supply planning of components. Our aim is to find the optimal values of the order periodicity and planned lead times at the offsetting step of the MRP procedure. The goal is to minimise the sum of the average component holding, finished product backlogging and setup costs. Several theoretical properties of the objective function are proven and an efficient optimization algorithm is developed. The proofs of the explicit form and properties of the objective function as well as the development of the optimization algorithm occupy a large portion of this paper. The method developed can be used for the optimization of time phasing and periodicity for such an MRP system under lead time uncertainties. © 2010 Elsevier B.V. All rights reserved.

Louly M.-A.,King Saud University | Dolgui A.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP
International Journal of Production Economics | Year: 2013

This study deals with Material Requirement Planning (MRP) software parameterization under uncertainties. The actual lead time has random deviations; so it can be considered as a random variable. MRP approach with Periodic Order Quantity (POQ) policy is considered. The aim is to find the optimal MRP time phasing corresponding to each periodicity of the POQ policy. This is a crucial issue in supply planning with MRP approach because inappropriate planned lead times under lead time uncertainties invariably lead to large and costly inventories or insufficient customer service levels. The proposed model and algorithms minimize the sum of the setup and holding costs while satisfying a constraint on the service level. Our approach does not need to employ the commonly used normal probability distributions. Instead, its originality is in finding a closed form of the objective function, valid for any probability distribution of the actual lead times. © 2011 Elsevier B.V.

Elkhatib M.E.,University of Waterloo | El-Shatshat R.,University of Waterloo | Salama M.M.A.,King Saud University
IEEE Transactions on Smart Grid | Year: 2011

In this paper a novel coordinated voltage control scheme is proposed to enable voltage regulator to efficiently regulate the voltage of multiple feeders in the presence of DGs. The proposed technique is based on placing a remote terminal unit (RTUs) at each DG and each line capacitor. These RTUs coordinate together, through communication, and form a multiagent system. Detailed analysis is given for the estimation of the voltage profile based on the RTUs readings. The conditions under which the usage of one voltage regulator for the regulation of multiple-feeders fails are presented along with proposed solutions for such situation. Simulation results show that this technique enable a considerable increase in the allowed DG injected power to the system. © 2011 IEEE.

El-Bashir S.M.,King Saud University | El-Bashir S.M.,Banha University
Journal of Luminescence | Year: 2012

This work concerning the photophysical properties of fluorescent nanohybrid films based on poly(methylmethacrylate) (PMMA) doped with coumarin dyestuff and entrapped with different concentrations of hydrophilic nanosilica. Spectroscopic tools were applied in order to determine the optimum concentration of nanosilica for the best optical properties for a matrix used as fluorescent solar concentrator. The optical constants and photoluminescence spectra of fluorescent nanohybrid films showed an enhancement of the photon trapping efficiency and matrix stability by increasing the concentration of SiO 2 nanoparticles. © 2012 Elsevier B.V.

Steinbrenner H.,Heinrich Heine University Düsseldorf | Sies H.,Heinrich Heine University Düsseldorf | Sies H.,King Saud University
Archives of Biochemistry and Biophysics | Year: 2013

The essential trace element selenium, as selenocysteine, is incorporated into antioxidant selenoproteins such as glutathione peroxidases (GPx), thioredoxin reductases (TrxR) and selenoprotein P (Sepp1). Although comparatively low in selenium content, the brain exhibits high priority for selenium supply and retention under conditions of dietary selenium deficiency. Liver-derived Sepp1 is the major transport protein in plasma to supply the brain with selenium, serving as a "survival factor" for neurons in culture. Sepp1 expression has also been detected within the brain. Presumably, astrocytes secrete Sepp1, which is subsequently taken up by neurons via the apolipoprotein E receptor 2 (ApoER2). Knock-out of Sepp1 or ApoER2 as well as neuron-specific ablation of selenoprotein biosynthesis results in neurological dysfunction in mice. Astrocytes, generally less vulnerable to oxidative stress than neurons, are capable of up-regulating the expression of antioxidant selenoproteins upon brain injury. Occurrence of neurological disorders has been reported occasionally in patients with inadequate nutritional selenium supply or a mutation in the gene encoding selenocysteine synthase, one of the enzymes involved in selenoprotein biosynthesis. In three large trials carried out among elderly persons, a low selenium status was associated with faster decline in cognitive functions and poor performance in tests assessing coordination and motor speed. Future research is required to better understand the role of selenium and selenoproteins in brain diseases including hepatic encephalopathy. © 2013 Elsevier Inc. All rights reserved.

Steinbrenner H.,Heinrich Heine University Düsseldorf | Speckmann B.,Queensland Institute of Medical Research | Sies H.,Heinrich Heine University Düsseldorf | Sies H.,King Saud University
Antioxidants and Redox Signaling | Year: 2013

Significance: Adequate and supranutritional selenium (Se) intake, maintaining full expression of selenoproteins, has been assumed to be beneficial for human health with respect to prevention of cancer. Strikingly, the effectiveness of dietary Se supplementation depends on many factors: baseline Se status, age, gender, and genetic background of an individual; type of cancer; and time point of intervention in addition to metabolic conversion and dose of applied Se compounds. Recent Advances: Se intake levels for optimization of plasma selenoproteins in humans have been delineated. Regulation, function, and genetic variants of several selenoproteins have been characterized in the intestine, where Se-mediated prevention of colorectal cancer appears to be particularly promising. Critical Issues: Numerous cell culture and animal studies indicate anticarcinogenic capacity of various Se compounds but, at present, the outcome of human studies is inconsistent and, in large part, disappointing. Moreover, supranutritional Se intake may even trigger adverse health effects, possibly increasing the risk for Type 2 diabetes in Se-replete populations. Future Directions: To improve protocols for the use of Se in cancer prevention, knowledge on cellular and systemic actions of Se compounds needs to be broadened and linked to individual-related determinants such as the occurrence of variants in selenoprotein genes and the Se status. Based on better mechanistic insight, populations and individuals that may benefit most from dietary Se supplementation need to be defined and studied in suitably planned intervention trials. Antioxid. Redox Signal. 19, 181-191. © Mary Ann Liebert, Inc.

News Article | November 16, 2016
Site: www.eurekalert.org

Québec City, November 16, 2016--A large number of mouth cells exposed to e-cigarette vapor in the laboratory die within a few days, according to a study conducted by Université Laval researchers and published in the latest issue of Journal of Cellular Physiology. Dr. Mahmoud Rouabhia and his team at Université Laval's Faculty of Dental Medicine came to this conclusion after exposing gingival epithelial cells to e-cigarette vapor. "Mouth epithelium is the body's first line of defense against microbial infection," Professor Rouabhia explains. "This epithelium protects us against several microorganisms living in our mouths." To simulate what happens in a person's mouth while vaping, researchers placed epithelial cells in a small chamber containing a saliva-like liquid. Electronic cigarette vapor was pumped into the chamber at a rate of two five-second "inhalations" per minute for 15 minutes a day. Observations under the microscope showed that the percentage of dead or dying cells, which is about 2% in unexposed cell cultures, rose to 18%, 40%, and 53% after 1, 2, and 3 days of exposure to e-cigarette vapor, respectively. "Contrary to what one might think, e-cigarette vapor isn't just water," explains Dr. Rouabhia. "Although it doesn't contain tar compounds like regular cigarette smoke, it exposes mouth tissues and the respiratory tract to compounds produced by heating the vegetable glycerin, propylene glycol, and nicotine aromas in e-cigarette liquid." The cumulative effects of this cell damage have not yet been documented, but they are worrying, according to Dr. Rouabhia, who is also a member of the Oral Ecology Research Group (GREB) at Université Laval: "Damage to the defensive barrier in the mouth can increase the risk of infection, inflammation, and gum disease. Over the longer term, it may also increase the risk of cancer. This is what we will be investigating in the future." In addition to Mahmoud Rouabhia, the study's coauthors are: Hyun Jin Park, Andrew Zakrzewski, Witold Chmielewski, and Jamila Chakir (Université Laval); Abdelhabib Semlali (King Saud University).

Saraswati S.,King Saud University | Kumar S.,North - Eastern Hill University | Alhaider A.A.,King Saud University
Molecular Cancer | Year: 2013

Background: VEGF receptor 2 (VEGFR2) inhibitors, as efficient antiangiogenesis agents, have been applied in the cancer treatment. However, recently, most of these anticancer drugs have some adverse effects. Discovery of novel VEGFR2 inhibitors as anticancer drug candidates is still needed. Methods: We used α-santalol and analyzed its inhibitory effects on human umbilical vein endothelial cells (HUVECs) and Prostate tumor cells (PC-3 or LNCaP) in vitro. Tumor xenografts in nude mice were used to examine the in vivo activity of α-santalol. Results: α-santalol significantly inhibits HUVEC proliferation, migration, invasion, and tube formation. Western blot analysis indicated that α-santalol inhibited VEGF-induced phosphorylation of VEGFR2 kinase and the downstream protein kinases including AKT, ERK, FAK, Src, mTOR, and pS6K in HUVEC, PC-3 and LNCaP cells. α-santalol treatment inhibited ex vivo and in vivo angiogenesis as evident by rat aortic and sponge implant angiogenesis assay. α-santalol significantly reduced the volume and the weight of solid tumors in prostate xenograft mouse model. The antiangiogenic effect by CD31 immunohistochemical staining indicated that α-santalol inhibited tumorigenesis by targeting angiogenesis. Furthermore, α-santalol reduced the cell viability and induced apoptosis in PC-3 cells, which were correlated with the downregulation of AKT, mTOR and P70S6K expressions. Molecular docking simulation indicated that α-santalol form hydrogen bonds and aromatic interactions within the ATP-binding region of the VEGFR2 kinase unit.Conclusion: α-santalol inhibits angiogenesis by targeting VEGFR2 regulated AKT/mTOR/P70S6K signaling pathway, and could be used as a potential drug candidate for cancer therapy. © 2013 Saraswati et al.; licensee BioMed Central Ltd.

Batoo K.M.,King Saud University | El-Sadek M.-S.A.,South Valley University
Journal of Alloys and Compounds | Year: 2013

Nanoscale Ni0.7-xMgxCu 0.3Fe2O4 (0.0 ≤ x ≤ 0.5) ferrite powders were prepared by sol-gel method and obtained as dried gel after successful reaction between respective metal nitrates. X-ray diffraction (XRD) confirmed the successful synthesis of materials, and the formation of single-phase cubic spinel structure. The average particle sizes of these materials were found between 40 to 50 nm and confirmed by TEM (±1). Dielectric constant (*′) measured in the frequency range (42 Hz to 5 MHz) was found to decrease with increasing frequency of the applied field, which shows normal behavior, and has been explained in the light of Maxwell-Wagner interfacial polarization. Debye relaxation peaks were observed for lower concentration of Mg in frequency dependent dielectric loss tangent curves. Real and imaginary parts of impedance (Z′ and Z″) suggest existence of one relaxation mechanism which is attributed to the co-effect of grains and grain boundaries. The room temperature dc magnetization studies infer magnetic moment of Ni-Cu-Mg nanoparticles decreases with increasing Mg2+ doping content. © 2013 Elsevier B.V. All rights reserved.

Amin M.T.,King Saud University | Han M.Y.,Seoul National University
Desalination | Year: 2011

The inefficiency of solar disinfection (SODIS) for the disinfection purposes can be improved by concentrating the sunlight i.e. by using solar collector disinfection (SOCO-DIS) system as investigated by authors in previous research or by increasing the exposure time of the targeted water to direct sunlight. Under weak sunlight conditions, however, this still remained ineffective as highlighted by earlier research. The efficiency of solar-based disinfection systems for the treatment of stored rainwater is further improved based on the better performance of these systems at low pH, by adding commonly available and inexpensive food preservative products, such as lemon and vinegar. Lemon and vinegar both increased the disinfection efficiency in SODIS by about 40% and completely disinfected rainwater in a SOCO-DIS system under weak weather conditions by lowering the pH to 3. An optimum combination of 2.5. ml (0.25%) of lemon and 1.7. ml (0.17%) of vinegar was selected to avoid any taste or odor problems while maintaining complete disinfection. Results showed that the choice of catalyst (lemon or vinegar in this study) was also an important factor in addition to low pH for disinfection using sunlight. © 2011 Elsevier B.V.

Khalil K.A.,King Saud University | Khalil K.A.,South Valley University | Almajid A.A.,King Saud University
Materials and Design | Year: 2012

Recently, efforts have been undertaken to develop nanostructured materials with enhanced mechanical and microstructural properties for use in various fields of materials engineering. The purpose of the present study was to help clarify and optimize the overall processing parameters of the high-frequency induction heat sintering (HFIHS) process, such as sintering temperatures, times, pressures and heating rates, focusing on the sintering of nanostructured powders and the suitability of the HFIHS process for combining a high sintering density with inhibited grain growth. In this study, super-fast densification behavior and the attendant mechanical and microstructural features of magnesium/1. wt% hydroxyapatite (Mg/1. wt% HAp) bio-nanocomposites processed by HFIHS were investigated. The results indicate that a nano-grained, nearly fully dense Mg/HAp nanostructure with a small crystal size (<40. nm) could be obtained by optimizing the overall processing parameters. A relative density, microhardness and compressive strength for the nanocomposite of approximately 99.7%, 60. HV and 194.5. MPa, respectively, were obtained. Phase analysis using X-ray diffraction (XRD) shows no major variations between the product and starting materials. © 2011 Elsevier Ltd.

Bosilevac J.M.,U.S. Department of Agriculture | Koohmaraie M.,Forest Laboratories | Koohmaraie M.,King Saud University
Applied and Environmental Microbiology | Year: 2011

Escherichia coli O157:H7 is a Shiga toxin (stx)-producing E. coli (STEC) strain that has been classified as an adulterant in U.S. beef. However, numerous other non-O157 STEC strains are associated with diseases of various severities and have become an increasing concern to the beef industry, regulatory officials, and the public. This study reports on the prevalence and characterization of non-O157 STEC in commercial ground beef samples (n = 4,133) obtained from numerous manufacturers across the United States over a period of 24 months. All samples were screened by DNA amplification for the presence of Shiga toxin genes, which were present in 1,006 (24.3%) of the samples. Then, culture isolation of an STEC isolate from all samples that contained stx1 and/or stx2 was attempted. Of the 1,006 positive ground beef samples screened for stx, 300 (7.3% of the total of 4,133) were confirmed to have at least one strain of STEC present by culture isolation. In total, 338 unique STEC isolates were recovered from the 300 samples that yielded an STEC isolate. All unique STEC isolates were serotyped and were characterized for the presence of known virulence factors. These included Shiga toxin subtypes, intimin subtypes, and accessory virulence factors related to adherence (saa, iha, lifA), toxicity (cnf, subA, astA), iron acquisition (chuA), and the presence of the large 60-MDa virulence plasmid (espP, etpD, toxB, katP, toxB). The isolates were also characterized by use of a pathogenicity molecular risk assessment (MRA; based on the presence of various O-island nle genes). Results of this characterization identified 10 STEC isolates (0.24% of the 4,133 total) that may be considered a significant food safety threat, defined by the presence of eae, subA, and nle genes. © 2011, American Society for Microbiology.

Swarbrick H.A.,University of New South Wales | Alharbi A.,King Saud University | Watt K.,University of New South Wales | Lum E.,University of New South Wales | Kang P.,University of New South Wales
Ophthalmology | Year: 2015

Purpose To investigate the effect of overnight orthokeratology (OK) contact lens wear on axial length growth in East Asian children with progressive myopia. Design A prospective, randomized, contralateral-eye crossover study conducted over a 1-year period. Participants We enrolled 26 myopic children (age range, 10.8-17.0 years) of East Asian ethnicity. Methods Subjects were fitted with overnight OK in 1 eye, chosen at random, and conventional rigid gas-permeable (GP) lenses for daytime wear in the contralateral eye. Lenses were worn for 6 months. After a 2-week recovery period without lens wear, lens-eye combinations were reversed and lens wear was continued for a further 6 months, followed by another 2-week recovery period without lens wear. Axial eye length was monitored at baseline and every 3 months using an IOLMaster biometer. Corneal topography (Medmont E300) and objective refraction (Shin-Nippon NVision-K 5001 autorefractor) were also measured to confirm that OK lens wear was efficacious in correcting myopia. Main Outcome Measurements Axial length elongation and myopia progression with OK were compared with conventional daytime rigid contact lens wear. Results After 6 months of lens wear, axial length had increased by 0.04±0.06 mm (mean ± standard deviation) in the GP eye (P = 0.011) but showed no change (-0.02±0.05 mm) in the OK eye (P = 0.888). During the second 6-month phase of lens wear, in the OK eye there was no change from baseline in axial length at 12 months (-0.04±0.08 mm; P = 0.218). However, in the GP eye, the 12-month increase in axial length was significant (0.09±0.09 mm; P < 0.001). The GP lens-wearing eye showed progressive axial length growth throughout the study. Conclusions These results provide evidence that, at least in the initial months of lens wear, overnight OK inhibits axial eye growth and myopia progression compared with conventional GP lenses. Apparent shortening of axial length early in OK lens wear may reflect the contribution of OK-induced central corneal thinning, combined with choroidal thickening or recovery due to a reduction or neutralization of the myopiogenic stimulus to eye growth in these myopic children. © 2015 American Academy of Ophthalmology.

Xu A.,University of Hong Kong | Vanhoutte P.M.,University of Hong Kong | Vanhoutte P.M.,King Saud University
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2012

The heart and blood vessels are surrounded by epicardial and perivascular adipose tissues, respectively, which play important roles in maintaining cardiovascular homeostasis by secreting a number of biologically active molecules, termed "adipokines." Many of these adipokines function as an important component of the 'adipo-cardiovascular axis' mediating the cross talk between adipose tissues, the heart, and the vasculature. On the one hand, most adipokines [including tumor necrosis factor-α, resistin, adipocyte fatty acid binding protein (A-FABP), and lipocalin-2] are proinflammatory and causally associated with endothelial and cardiac dysfunction by their endocrine/paracrine actions. On the other hand, adiponectin is one of the few adipokines that possesses multiple salutary effects on the prevention of cardiovascular disease, because of its pleiotropic actions on the heart and the blood vessels. The discordant production of adipokines in dysfunctional adipose tissue is a key contributor to obesity-related cardiovascular disease. This review provides an update in understanding the roles of adipokines in the pathogenesis of cardiovascular disorders associated with obesity and diabetes and focuses on the two most abundant adipokines, adiponectin and A-FABP. Indeed, data from both animal studies and clinical investigations imply that these two adipokines are prognostic biomarkers for cardiovascular disease and even promising therapeutic targets for its treatment. © 2012 the American Physiological Society.

Lam A.Y.S.,University of California at Berkeley | Li V.O.K.,University of Hong Kong | Li V.O.K.,King Saud University | Yu J.J.Q.,University of Hong Kong
IEEE Transactions on Evolutionary Computation | Year: 2012

Optimization problems can generally be classified as continuous and discrete, based on the nature of the solution space. A recently developed chemical-reaction-inspired metaheuristic, called chemical reaction optimization (CRO), has been shown to perform well in many optimization problems in the discrete domain. This paper is dedicated to proposing a real-coded version of CRO, namely, RCCRO, to solve continuous optimization problems. We compare the performance of RCCRO with a large number of optimization techniques on a large set of standard continuous benchmark functions. We find that RCCRO outperforms all the others on the average. We also propose an adaptive scheme for RCCRO which can improve the performance effectively. This shows that CRO is suitable for solving problems in the continuous domain. © 2012 IEEE.

Simos T.E.,King Saud University | Simos T.E.,University of Peloponnese
Journal of Mathematical Chemistry | Year: 2014

In this paper we will develop an explicit fourth algebraic order four-step method with phase-lag and its first and second derivatives vanished. The comparative error and the stability analysis of the above mentioned paper is also presented. The new obtained method is applied on the resonance problem of the Schrödinger equationIn order in order to examine its efficiency. The theoretical and the computational results shown that the new obtained method is more efficient than other well known methods for the numerical solution of the Schrödinger equation and related initial-value or boundary-value problems with periodic and/or oscillating solutions. © 2013 Springer Science+Business Media New York.

Panopoulos G.A.,University of Peloponnese | Anastassi Z.A.,Qatar University | Simos T.E.,University of Peloponnese | Simos T.E.,King Saud University
Astronomical Journal | Year: 2013

A new multistep predictor-corrector (PC) pair form is introduced for the numerical integration of second-order initial-value problems. Using this form, a new eight-step symmetric embedded predictor-corrector method is constructed. The new PC method is based on the multistep symmetric method of Quinlan & Tremaine, with eight steps and eighth algebraic order, and is constructed to solve numerically the N-body problem. The new integrator has algebraic order 10 and it can be used to solve problems, for which the frequency is not known. We investigate the behavior of the new algorithm by integrating the five outer-planet problem and the two-body problem with various eccentricities. Regarding the five outer-planet problem, we calculate the error of the integrator in the solution, the Hamiltonian, and the phase after forward and backward integration over various intervals that are multiples of the period of Jupiter. © 2013. The American Astronomical Society. All rights reserved.

Simos T.E.,King Saud University | Simos T.E.,University of Peloponnese
Journal of Mathematical Chemistry | Year: 2012

In this paper we study the connection between: (i) closed Newton-Cotes formulae of high order, (ii) trigonometrically-fitted and exponentially-fitted differential methods, (iii) symplectic integrators. Several one step symplectic integrators have been produced based on symplectic geometry during the last decades (see the relevant literature and the references here). However, the study of multistep symplectic integrators is very poor. In this paper we investigate the High Order Closed Newton-Cotes Formulae and we write them as symplectic multilayer structures. We develop trigonometrically-fitted and exponentially-fitted symplectic methods which are based on the closed Newton-Cotes formulae. We apply the symplectic schemes in order to solve the resonance problem of the radial Schrödinger equation. Based on the theoretical and numerical results, conclusions on the efficiency of the new obtained methods are given. © 2011 Springer Science+Business Media, LLC.

Simos T.E.,King Saud University | Simos T.E.,University of Peloponnese
Journal of Mathematical Chemistry | Year: 2011

In this paper we introduce a new explicit hybrid Numerov-type method. This method is of fourth algebraic order and has phase-lag and its first two derivatives equal to zero. We present a stability analysis and an error analysis based on the radial Schrödinger equation. Finally we apply the new proposed method to the resonance problem of the radial Schrödinger equation and we present the final conclusion based on the theoretical analysis and numerical results. © 2011 Springer Science+Business Media, LLC.

Kalogiratou Z.,Technological Educational Institution of Western Macedonia at Kastoria | Monovasilis T.,Technological Educational Institute of West Macedonia | Psihoyios G.,University of Peloponnese | Simos T.E.,University of Peloponnese | Simos T.E.,King Saud University
Physics Reports | Year: 2014

In this work we review single step methods of the Runge-Kutta type with special properties. Among them are methods specially tuned to integrate problems that exhibit a pronounced oscillatory character and such problems arise often in celestial mechanics and quantum mechanics. Symplectic methods, exponentially and trigonometrically fitted methods, minimum phase-lag and phase-fitted methods are presented. These are Runge-Kutta, Runge-Kutta-Nyström and Partitioned Runge-Kutta methods. The theory of constructing such methods is given as well as several specific methods. In order to present the performance of the methods we have tested 58 methods from all categories. We consider the two dimensional harmonic oscillator, the two body problem, the pendulum problem and the orbital problem studied by Stiefel and Bettis. Also we have tested the methods on the computation of the eigenvalues of the one dimensional time independent Schrödinger equation with the harmonic oscillator, the doubly anharmonic oscillator and the exponential potentials. © 2013 Elsevier B.V..

El-Fayez F.F.M.,Electronics Research Institute of Egypt | El-Fayez F.F.M.,King Saud University
IEEE Transactions on Industrial Electronics | Year: 2010

This paper proposes a hybrid H∞-based wavelet-neural- network (WNN) position tracking controller as a new robust motion-control system for permanent-magnet synchronous motor (PMSM) servo drives. The combinations of both WNN and H∞ controllers would insure the robustness and overcome the uncertainties of the servo drive. The new controller combines the merits of the H∞ control with robust performance and the WNN control (WNNC) which combines the capability of NNs for online learning ability and the capability of wavelet decomposition for identification ability. The online trained WNNC is utilized to predict the uncertain system dynamics to relax the requirement of uncertainty bound in the design of the H ∞ controller. The WNNC generates an adaptive control signal to attain robust performance regardless of parameter uncertainties (PU) and load disturbances. Systematic methodology for both controllers' design is provided. A computer simulation is developed to demonstrate the effectiveness of the proposed WNN-based H∞ controller. An experimental system is established to validate the effectiveness of the drive system. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulated and experimental results confirm that the new motion controller grants robust performance and precise dynamic response regardless of load disturbances and PMSM PU. © 2006 IEEE.

Panopoulos G.A.,University of Peloponnese | Simos T.E.,University of Peloponnese | Simos T.E.,King Saud University
Computer Physics Communications | Year: 2014

Our new phase-fitted embedded predictor-corrector method (EPCM) presented here is based on the multistep symmetric method of Quinlan-Tremaine (1990), with eight steps and eighth algebraic order and constructed to solve numerically the two-dimensional Kepler problem. It can also be used to integrate other orbital problems and related IVPs with oscillatory solutions. First we present a EPCM (Panopoulos et al. (2011) and Panopoulos et al. (2013)) pair form. From this form we construct a new eight-step method. The new scheme has algebraic order ten and infinite order of phase-lag. We tested the efficiency of our newly developed scheme against to some recently constructed optimized methods and other well known methods from the literature. We measure the efficiency of the methods and conclude that the new scheme is noticeably more efficient of all the compared methods and for all the problems solved, including the radial Schrödinger equation. © 2013 Elsevier B.V. All rights reserved.

Rashidi M.M.,Bu - Ali Sina University | Ali M.,King Saud University | Freidoonimehr N.,Bu - Ali Sina University | Nazari F.,Islamic Azad University
Energy | Year: 2013

The present study first of all concerns the first and second law analyzes of an electrically conducting fluid past a rotating disk in the presence of a uniform vertical magnetic field, analytically via Homotopy Analysis Method (HAM), and then applies Artificial Neural Network (ANN) and Particle Swarm Optimization (PSO) algorithm in order to minimize the entropy generation. In the first part of this study, entropy generation equation is derived as a function of velocity and temperature gradients and non-dimensionalized using geometrical and physical flow field-dependent parameters. A very good agreement can be seen between some of the obtained results of the current study and the results of the previously published data. The effects of physical flow parameters such as magnetic interaction parameter, unsteadiness parameter, disk stretching parameter, Prandtl number, Reynolds number and Brinkman number on all fluid velocity components, temperature distribution and the averaged entropy generation number are checked and analyzed. For minimizing the entropy generation value a procedure based on ANN and PSO is proposed. This procedure comprises three steps. The first step is to find entropy generation for values of some different affecting factors. In the second step, some distinct multi-layer perceptron ANNs based on the data obtained from step one are trained. In step three, PSO is used to minimize the entropy generation in the considered stretchable rotating disk. © 2013 Elsevier Ltd.

Simos T.E.,King Saud University | Simos T.E.,University of Peloponnese
International Journal of Modern Physics C | Year: 2013

The investigation on the connection between: (1) closed Newton-Cotes formulae of high-order, (2) trigonometrically-fitted differential schemes and (3) symplectic integrators is presented in this paper. In the last decades, several one step symplectic methods were obtained based on symplectic geometry (see the appropriate literature). The investigation on multistep symplectic integrators is poor. In the present paper: (1) we study a trigonometrically- fitted high-order closed Newton-Cotes formula, (2) we investigate the necessary conditions in a general eight-step differential method to be presented as symplectic multilayer integrator, (3) we present a comparative error analysis in order to show the theoretical superiority of the present method, (4) we apply it to solve the resonance problem of the radial Schrödinger equation. Finally, remarks and conclusions on the efficiency of the new developed method are given which are based on the theoretical and numerical results. © 2013 World Scientific Publishing Company.

Khan M.K.,King Saud University | Kim S.-K.,Korea University | Alghathbar K.,King Saud University
Computer Communications | Year: 2011

Remote user authentication is a method, in which remote server verifies the legitimacy of a user over an insecure communication channel. Currently, smart card-based remote user authentication schemes have been widely adopted due to their low computational cost and convenient portability for the authentication purpose. Recently, Wang et al. proposed a dynamic ID-based remote user authentication scheme using smart cards. They claimed that their scheme preserves anonymity of user, has the features of strong password chosen by the server, and protected from several attacks. However, in this paper, we point out that Wang et al.'s scheme has practical pitfalls and is not feasible for real-life implementation. We identify that their scheme: does not provide anonymity of a user during authentication, user has no choice in choosing his password, vulnerable to insider attack, no provision for revocation of lost or stolen smart card, and does provide session key agreement. To remedy these security flaws, we propose an enhanced authentication scheme, which covers all the identified weaknesses of Wang et al.'s scheme and is more secure and efficient for practical application environment. © 2010 Elsevier B.V. All rights reserved.

German Cancer Research Center and King Saud University | Date: 2013-06-12

Described are shuffled fragments of the genes encoding HPV 16 E6/E7 useful as a therapeutic vaccine against persistent HPV infections and HPV-related tumors, e.g, cervical carcinoma.

Simos T.E.,King Saud University | Simos T.E.,University of Peloponnese
Applied Mathematics and Information Sciences | Year: 2014

In the present paper, we will investigate a family of explicit four-step methods first introduced by Anastassi and Simos [1] for the case of vanishing of phase-lag and its first derivative. These methods are efficient for the numerical solution of the Schrödinger equation and related initial-value or boundary-value problems with periodic and/or oscillating solutions. As we mentioned before the main scope of this paper is the study of the elimination of the phase-lag and its first derivative of the family of the methods to be investigated. A comparative error and stability analysis will be presented for the studied family of four-step explicit methods. The new obtained methods will finally be tested on the resonance problem of the Schrödinger equation in order to examine their efficiency.

Baig M.,King Saud University | Khan A.S.,University of Maryland Baltimore County | Choi S.-H.,Sunchon National University | Jeong A.,Sunchon National University
International Journal of Plasticity | Year: 2013

In this paper, the experimental response of oxygen free high conductivity (OFHC) copper under multiaxial loading conditions is presented, along with quasi-static and dynamic response under uniaxial compression loading. The multiaxial experiments were performed under non-proportional loading conditions, where the sample was subjected to uniaxial loading for a predetermined strain followed by biaxial loading. These experimental results provide a comprehensive data set for constitutive modeling of the material response at finite strains, over a wide range of strain-rates and temperatures. The observed strain-rate and temperature dependent responses under uniaxial loading are shown to correlate closely using the Khan-Huang-Liang (KHL) constitutive model; the model is shown to be in close agreement with other published experimental results [Khan, A.S.; Liang, R.; 1999. Behavior of three BCC metal over a wide range of strain rates and temperatures. International Journal of Plasticity 15, 1089-1109; Nemat-Nasser, S.; Li, Y.; 1998. Flow stress of F.C.C polycrystals with applications to OFHC Cu. Acta Materialia 46 (2), 565-577]. This constitutive model is further demonstrated to predict the observed material response accurately, using the material constants determined from uniaxial loading results during proportional and non-proportional loading experiments. The micro-texture characterization of as-extruded, annealed and deformed samples was performed to investigate the effect of temperature and strain-rate on texture evolution of OFHC copper. Grain average misorientation (GAM) was used to reveal the deformation heterogeneity and orientation gradients in deformed samples. © 2012 Elsevier Ltd. All rights reserved.

Bartke A.,University of Illinois at Springfield | Bartke A.,King Saud University
Gerontology | Year: 2012

A recent report of virtually complete protection from diabetes and cancer in a population of people with hereditary dwarfism revived interest in elucidating the relationships between growth, adult body size, age-related disease and longevity. In many species, smaller individuals outlive those that are larger and a similar relationship was shown in studies of various human populations. Adult body size is strongly dependent on the actions of growth hormone (GH) and the absence of GH or GH receptor in mice leads to a remarkable extension of longevity. Many mechanisms that may account for, or contribute to, this association have been identified. It is suggested that modest modifications of the diet at different ages may extend human healthspan and lifespan by reducing levels of hormones that stimulate growth. Copyright © 2012 S. Karger AG, Basel.

Alzahrani S.,King Saud University | Mohammad A.W.,National University of Malaysia
Journal of Water Process Engineering | Year: 2014

This review provides insight into the implementation of membrane technology in the petroleum industry for treating produced water that is generated from conventional oilfields in upstream and downstream processes. The ever-evolving and increasingly stringent regulatory standards for discharging produced water pose colossal environmental and economic implications because the bulk of this produced water is disposed into the environment. Thus, a review of the implementation of membrane technology for produced water treatment could contribute to the knowledge required for the increased introduction of scaled-up membrane technology in the petroleum industry. This review encompasses the capabilities and performance optimization possibilities of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis membranes. The level of applications that these membrane technologies might attain within the petroleum industry were determined, and these implementations were correlated with the purpose, performance efficiency, treatment system configurations, necessary pretreatment procedures, quality of treated produced water, fouling occurrence and control, foulants, cleaning procedures, raw produced water content, potential challenges with corresponding applied solutions, and economic factors. This review also maps current and future trends and provides a perspective on the outlook for advances in novel membrane applications for produced water treatment. © 2014 Elsevier Ltd.

King Saud University, King Abdulaziz City for Science and Technology | Date: 2011-11-04

The proposed invention is an indoor firefighting robot which has the capability to climb stairs and negotiate several types of floor materials inside buildings. it can withstand very high temperature up to 700 Celsius for as long as 60 minutes using multiple thermal insulation technique. It can communicate with trapped and injured persons inside the fire scene and can send back video and audio information describing the fire environment inside the building to the controller. It has also an insulated container at the rear with oxygen masks to help victims to breathe safely in the smoke environment in the early stage of the firefighting process. Several of these compact firefighting robots can be launched and can work together inside the room or multiple rooms under fire with assistance of remote control unit. The fire robot can avoid obstacles while trying to rescue injured victims.

King Abdulaziz City for Science, Technology and King Saud University | Date: 2016-04-11

A vehicle safety device for reducing whiplash in a vehicle includes a curved guide configured to allow a seat to slide thereon, an impact sensor that can detect an impact on a rear end of the vehicle; and a locking mechanism that can allow the seat to slide on the curved guide when an impact is detected by the impact sensor. The locking mechanism can prevent the seat from moving relative to the curved guide when there is no impact detected by the impact sensor.

King Abdulaziz City for Science, Technology and King Saud University | Date: 2013-02-21

The invention relates to the development of a catalyst for selectively producing acetic acid from a gaseous feedstock of ethane, ethylene or mixtures thereof and oxygen at a low temperature. Said gaseous feedstock is brought together with a catalyst containing the oxides of Mo, V and Nb and nano metallic Pd optionally together with a hetero-poly acid and/or Sb and Ca. The present catalytic system provides both higher selectivity and yield of acetic with minimal production of side products of ethylene and CO.

King Saud University, King Abdulaziz City for Science and Technology | Date: 2010-11-24

An isolation base system for sensitive structures such as nuclear power plant modules is suggested. The proposed isolation system considers a base supported on specially designed hollow spherical balls and equipped with 3 linear hydraulic actuators to restrict the lateral motion of the base and provide a stable base under normal conditions. The actuators are released when an earthquake signal is detected to allow the base to oscillate freely during the earthquake attack. The hydraulic actuators are reactivated after shock wave ends to compress the springs and restore the base to its original position.

Simos T.E.,King Saud University | Simos T.E.,University Sidi Mohammed Ben Abdellah
Journal of Chemical Physics | Year: 2010

In this paper, we introduce new integrators of Newton-Cotes type and investigate the connection between these new methods, differential methods, and symplectic integrators. From the literature, we can see that several one step symplectic integrators have been obtained based on symplectic geometry. However, the investigation of multistep symplectic integrators is very poor. In this paper, we introduce a new numerical method of closed Newton-Cotes type and we write it as a symplectic multilayer structure. We apply the symplectic schemes in order to solve Hamilton's equations of motion which are linear in position and momentum. We observe that the Hamiltonian energy of the system remains almost constant as integration proceeds. © 2010 American Institute of Physics.

Halwani R.,King Saud University | Al-Muhsen S.,King Saud University | Hamid Q.,King Saud University | Hamid Q.,McGill University
Current Opinion in Pharmacology | Year: 2010

Asthmatic airway remodeling is the pathophysiological modifications of the normal airway wall structure which include changes in the composition and organization of its cellular and molecular constituents. These modifications are the major cause of the symptoms associated with decreased pulmonary function. Airway remodeling is partially reversible in mild asthma but mostly irreversible in chronic severe asthma. It is initiated as a repair process in response to airway wall injuries caused by inflammation; however, dysregulation of this process leads to airway remodeling. In this review, we will summarize the most recent findings about the different structural changes in airways of asthmatics as well as mediators involved in this process. © 2010 Elsevier Ltd.

Al-Muhsen S.,King Saud University | Al-Muhsen S.,McGill University | Johnson J.R.,McGill University | Hamid Q.,King Saud University | Hamid Q.,McGill University
Journal of Allergy and Clinical Immunology | Year: 2011

Airway remodeling encompasses the structural alterations in asthmatic compared with normal airways. Airway remodeling in asthmatic patients involves a wide array of pathophysiologic features, including epithelial changes, increased smooth muscle mass, increased numbers of activated fibroblasts/myofibroblasts, subepithelial fibrosis, and vascular changes. Multiple cytokines, chemokines, and growth factors released from both inflammatory and structural cells in the airway tissue create a complex signaling environment that drives these structural changes. However, recent investigations have changed our understanding of asthma from a purely inflammatory disease to a disease in which both inflammatory and structural components are equally involved. Several reports have suggested that asthma primarily develops because of serious defects in the epithelial layer that allow environmental allergens, microorganisms, and toxins greater access to the airway tissue and that can also stimulate the release of mediators from the epithelium, thus contributing to tissue remodeling. Lung-resident fibroblasts and smooth muscle cells have also been implicated in the pathogenesis of airway remodeling. Remodeling is assumed to result in persistent airflow limitation, a decrease in lung function, and airway hyperresponsiveness. Asthmatic subjects experience an accelerated decrease in lung function compared with healthy subjects, which is proportionally related to the duration and severity of their disease. © 2011 American Academy of Allergy, Asthma & Immunology.

Marie P.J.,Institute National Of La Sante Et Of La Recherche Medicale Unite 606 | Marie P.J.,University Paris Diderot | Kassem M.,University of Southern Denmark | Kassem M.,King Saud University
Journal of Clinical Endocrinology and Metabolism | Year: 2011

Context: Age-related bone loss is associated with progressive changes in bone remodeling characterized by decreased bone formation relative to bone resorption. Both trabecular and periosteal bone formation decline with age in both sexes, which contributes to bone fragility and increased risk of fractures. Studies in rodents and humans revealed that, independent of sex hormone deficiency, the age-related decline in bone formation is characterized by decreased osteoblast number and lifespan and reduced bone-forming capacity of individual osteoblasts. An important clinical question is to identify the mechanisms involved in the age-related defective bone formation. Evidence Acquisition: The mechanisms discussed in this review are based on a PubMed search and knowledge of the authors in the field. Evidence Synthesis: Available basic and clinical studies indicate that multiple mechanisms are involved in the alterations of osteoblastogenesis and the resulting decline in bone formation with aging. Notably, the age-related osteoblast dysfunctions and defective bone formation are caused by a number of extrinsic clinical factors that inhibit anabolic signaling pathways in bone. Thus, targeting these pathways can abolish age-related bone loss. Conclusions: The identification of extrinsic mechanisms involved in osteoblast dysfunctions associated with aging improves our knowledge of age-related bone loss and provides a basis for therapeutic intervention to improve bone formation and bone mass in the aging population. Copyright © 2011 by The Endocrine Society.

Hasanien H.M.,King Saud University | Muyeen S.M.,The Petroleum Institute
Electric Power Systems Research | Year: 2012

In wind energy conversion system, variable speed operation is becoming popular nowadays, where conventional synchronous generators, permanent magnet synchronous generators, and doubly fed induction generators are commercially used as wind generators. Along with the existing and classical solutions of the aforementioned machines used in wind power applications, the switched reluctance generator (SRG) can also be considered as a wind generator due to its inherent characteristics such as simple construction, robustness, low manufacturing cost, etc. This paper presents a novel speed control of switched reluctance generator by using adaptive neural network (ANN) controller. The SRG is driven by variable speed wind turbine and it is connected to the grid through an asymmetric half bridge converter, DC-link, and DC-AC inverter system. Speed control is very important for variable speed operation of SRG to ensure maximum power delivery to the grid for any particular wind speed. Detailed modeling and control strategies of SRG as well as other individual components including wind turbine, converter, and inverter systems are presented. The effectiveness of the proposed system is verified with simulation results using the real wind speed data measured at Hokkaido Island, Japan. The dynamic simulation study is carried out using PSCAD/EMTDC. © 2011 Elsevier B.V.

Yager R.R.,The College of New Rochelle | Yager R.R.,King Saud University
IEEE Transactions on Fuzzy Systems | Year: 2011

Our concern here is with the multi-source fusion problem. Two important aspects of this problem are the representation of information provided by the sources and the formulation of the instructions on how to fuse the information provided, which we refer to as the fusion imperative. We investigate the use of a monotonic set measure as a means of representing the fusion imperative. We look at the fusion of various different types of information, precise data, uncertain information such as probabilistic and possibilistic. We also consider the case of imprecise uncertain information such as that represented by a Dempster-Shafer belief structure. © 2011 IEEE.

Yager R.R.,The College of New Rochelle | Yager R.R.,King Saud University
Information Sciences | Year: 2011

Our interest is in the fusion of information from multiple sources when the information provided by the individual sources is expressed in terms of an imprecise uncertainty measure. We observe that the Dempster-Shafer belief structure provides a framework for the representation of a wide class of imprecise uncertainty measures. We then discuss the fusion of multiple Dempster-Shafer belief structures using the Dempster rule and note the problems that can arise when using this fusion method because of the required normalization in the face of conflicting focal elements. We then suggest some alternative approaches fusing multiple belief structures that avoid the need for normalization. © 2011 Elsevier Inc. All rights reserved.

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