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Abha, Saudi Arabia

King Khalid University is a public university, distributed over several towns in the 'Asir Province in south-west Saudi Arabia, including Abha and al-Namas. On 26 July 1998, King Saud University and Imam Muhammad ibn Saud Islamic University merged to became King Khalid University. King Khalid University is a rapidly growing institution of higher education in Saudi Arabia. With around 70,000 students, it is one of the biggest centers of learning in the Middle East region with a reputation as a major provider of both further and higher education. The eLearning Center at KKU was established in 2005 as part of the university’s continuous efforts to provide the latest scientific methodologies to improve the educational process. Wikipedia.

Density functional theory (DFT) and time dependent DFT has been applied to shed light on the electronic properties, photophysical properties and electron injection in the photosensitizers 2-cyano-5-(4-(phenyl(4-vinylphenyl)amino) phenyl)penta-2,4-dienoic acid (TC4) and its derivatives. The ground state structures have been optimized by using DFT-B3LYP/6-31G** level of theory. The absorption spectra have been computed by using PCM-TDBHandHLYP/6-311 + G** level of theory. Generally, highest occupied molecular orbitals are delocalized on whole of the dye while lowest unoccupied molecular orbitals are localized on ligand C, conjugated chain and anchoring group. By substituting the vinyl at positions 3,3′ on A- and B-ligands leads toward red shift. The methoxy group as donor is better than the methyl which can improve the electron injection and coupling constant. The light harvesting efficiency of mono-methoxy derivative (11) would be comparable to TC4. The size effect of titanium dioxide (TiO2) (nanoparticles) has been investigated on the electronic structure of the dye. By increasing the size of TiO2 intra-molecular charge transfer from dye to nanoparticles enhanced. © 2013 Elsevier B.V. All rights reserved.

Alkuraya F.S.,King Khalid University
Genetics in Medicine | Year: 2010

Consanguineous unions permit the "reunion" of ancestral chromosomal segments in a pattern referred to as "autozygosity," which is essentially a special form of homozygosity. This has long been exploited as a gene mapping tool because it is relatively easy to track a recessive mutation by the surrounding pattern of homozygous markers. The recent advent of single nucleotide polymorphism microarrays has rapidly replaced the historical use of microsatellites for this purpose. In this review, the author discusses other exciting opportunities offered by this unique arrangement of the human genome that range from pure clinical to functional genomic applications. The emerging field of whole genome sequencing promises to unlock much of the potential of the "autozygome.". © 2010 Lippincott Williams & Wilkins.

The 4,6-di(thiophen-2-yl)pyrimidine has alternate pi-rich and pi-poor units. To reduce the HOMO-LUMO energy gap and improve the intra-molecular charge transfer pi-backbone has been elongated along with push-pull strategy. The ground state geometries have been optimized by using density functional theory. The frontier molecular orbitals, i.e., highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) have been conferred. The absorption spectra have been computed by using time dependent density functional theory. On the basis of ionization potentials, electron affinities and reorganization energies charge transfer properties have been discussed. We tuned the electronic, photophysical and charge transfer properties of 4,6-di(thiophen-2-yl)pyrimidine derivatives. It is expected that new designed derivatives might be better/comparable to commonly used hole transfer material (pentacene). The smaller reorganization energies revealing that the electron transfer properties of new designed derivatives might be better/comparable to commonly used electron transfer materials (tris(8-hydroxyquinolinato)aluminum). The structure-property relationship has been discussed. © 2013 Elsevier B.V. All rights reserved.

Alfaleh K.,King Khalid University
Cochrane database of systematic reviews (Online) | Year: 2011

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 associated morbidity. To compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe NEC and/or sepsis in preterm infants. For this update, searches were made of MEDLINE (1966 to October 2010), EMBASE (1980 to October 2010), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2010), and abstracts of annual meetings of the Society for Pediatric Research (1995 to 2010). Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age and/or < 2500 g birth weight were considered. Trials were included if they involved enteral administration of any live microbial supplement (probiotics) and measured at least one prespecified clinical outcome. Standard methods of the Cochrane Collaboration and its Neonatal Group were used to assess the methodologic quality of the trials, data collection and analysis. Sixteen eligible trials randomizing 2842 infants were included. Included trials were highly variable with regard to enrollment criteria (i.e. birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. Data regarding extremely low birth weight infants (ELBW) could not be extrapolated. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) (typical RR 0.35, 95% CI 0.24 to 0.52) and mortality (typical RR 0.40, 95% CI 0.27 to 0.60). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.90, 95% CI 0.76 to 1.07). The included trials reported no systemic infection with the probiotics supplemental organism. The statistical test of heterogeneity for NEC, mortality and sepsis was insignificant. Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our updated review of available evidence supports a change in practice. More studies are needed to assess efficacy in ELBW infants and assess the most effective formulation and dose to be utilized.

Experimental studies have been carried out to investigate effects of biodiesel fuels on diesel engine performance, Carbon monoxide (CO) and nitric oxide (NOX) emissions, exhaust gas temperature (TExhaust), oil temperature (TOil), wall temperature (TWall), and cylinder pressure with/without exhaust gas recirculation (EGR). Biodiesel fuels are prepared from cotton seed oil, palm oil and flax oil. All the measured parameters for biodiesel fuels are compared with the base diesel fuel with/without EGR for different engine speeds. Fuel inlet temperature of 120 °C gives minimum viscosity different between diesel and biodiesel fuels. Biodiesel fuels give slightly less brake power (BP), brake thermal efficiency ()/Bth) and slightly high brake specific fuel consumption (BSFC) and high fuel mass flow rate per cycle. Diesel fuel gives CO higher than biodiesel fuels due to less O atoms in fuel molecules. Biodiesel fuels give NOX higher than diesel fuel due to high oxygen content in biodiesel fuels molecules and cetane number (CN). As EGR increases, CO increases while NOX decreases due to decrease flame temperature and O2 in fresh air charge. For biodiesel fuels, TExhaust and TOil are higher than for diesel fuel. TWall for diesel fuel is higher than for all biodiesel fuels. Biodiesel fuels give peak cylinder pressure higher than diesel fuel. The position of peak cylinder pressure is arrangement as 11 crank angle degree (CAD) after top dead center (ATDC) for flax, 12 CAD ATDC for cotton, 14 CAD ATDC for palm and 20 CAD ATDC for diesel fuel respectively. The present work contributes in using biodiesel fuels as alternative fuel for diesel engines without major change for engines parts. For comparison between biodiesel and diesel fuels, the viscosity is not the main parameter affecting on engine performance and emissions. © 2013 Elsevier Ltd. All rights reserved.

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