Cumulative abiotic stresses and their effect on the antioxidant defense system in two species of wheat, Triticum durum Desf and Triticum aestivum L.

The combined effects of heat and UV-B on the antioxidant system and photosynthetic pigments were investigated in the leaves of T. durum Desf. and Triticum aestivum L. The photosynthetic pigment content, in vitro evaluation of the antioxidant system activities including DPPH radical scavenging activity, and super oxide anion radical scavenging activity were determined. In addition, the antioxidant enzyme activities, such as superoxide dismutase (SOD) and guaiacol peroxidase (GPX), were determined. Heat and UV-B irradiation alone caused a significant decrease in the photosynthetic pigment content, radical scavenging activity and super oxide radical scavenging activity in the two studied plants. The antioxidant enzymes SOD and GPX were stimulated in response to UV and/or heat stresses. The elevation of enzyme activities was higher under heat than under UV-B, especially in T. aestivum. According to our findings, it can be concluded that combined heat and UV-B provided cross-tolerance; otherwise, single stress was found to aggravate the responses

First Order Phase Transformation in Amorphous Ge25Se75 – xSbx Glasses

Non-isothermal Differential scanning calorimetry (DSC) technique was used to study the kinetics of first order phase transformation in Ge25Se75 – xSbx glasses. The X-ray diffraction (XRD) technique was employed to investigate the amorphous and crystalline phases in Ge25Se75 – xSbx glasses. From the heating rate dependences of crystallization temperature; the activation energy for crystallization and other kinetics parameters were derived. The temperature difference (Tc – Tg) and Tc is highest for the samples with 6 % of Sb. Hence, Ge25Se69Sb6 glass is most stable. The enthalpy released is found to be less for Ge25Se69Sb6 glass which further confirms its maximum stability. The activation energy of crystallization (Ec) is found to vary with compositions indicating a structural change due to the addition of Sb. The crystallization data are interpreted in terms of recent analyses developed for non-isothermal conditions. The present investigation indicates that both the glass transition and the crystallization processes occur in a single stage. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3101

Global, direct and diffuse solar radiation on horizontal and tilted surfaces in Jeddah, Saudi Arabia

The measured data of global and diffuse solar radiation on a horizontal surface, the number of bright sunshine hours, mean daily ambient temperature, maximum and minimum ambient temperatures, relative humidity and amount of cloud cover for Jeddah (lat. 21°42'37''N, long. 39°11'12''E), Saudi Arabia, during the period (1996-2007) are analyzed. The monthly averages of daily values for these meteorological variables have been calculated. The data are then divided into two sets. The sub-data set I (1996-2004) are employed to develop empirical correlations between the monthly average of daily global solar radiation fraction (H/H0) and the various weather parameters. The sub-data set II (2005-2007) are then used to evaluate the derived correlations. Furthermore, the total solar radiation on horizontal surfaces is separated into the beam and diffuses components. Empirical correlations for estimating the diffuse solar radiation incident on horizontal surfaces have been proposed. The total solar radiation incident on a tilted surface facing south Ht with different tilt angles is then calculated using both Liu and Jordan isotropic model and Klucher's anisotropic model. It is inferred that the isotropic model is able to estimate Ht more accurate than the anisotropic one. At the optimum tilt angle, the maximum value of Ht is obtained as ~36 (MJ/m2 day) during January. Comparisons with 22 years average data of NASA SSE Model showed that the proposed correlations are able to predict the total annual energy on horizontal and tilted surfaces in Jeddah with a reasonable accuracy. It is also found that at Jeddah, the solar energy devices have to be tilted to face south with a tilt angle equals the latitude of the place in order to achieve the best performance all year round.Solar radiation Sunshine hours Meteorological parameters Regression analysis Tilted surfaces

Estimation of global solar radiation on horizontal surfaces in Jeddah, Saudi Arabia

The measured data of global solar radiation on a horizontal surface, as well as the number of sunshine hours, mean daily ambient temperature, maximum and minimum ambient temperatures, relative humidity and amount of cloud cover, for Jeddah (latitude 21° 42'37''N, longitude 39° 11'12''E), Saudi Arabia for the period 1996-2006 are analyzed. The data are divided into two sets. The sub-data set 1 (1996-2004) are employed to develop empirical correlations between the monthly average of daily global solar radiation fraction (H/H0) and various meteorological parameters. The nonlinear Angström type model developed by Sen and the trigonometric function model proposed by Bulut and Büyükalaca are also evaluated. New empirical constants for these two models have been obtained for Jeddah. The sub-data set 2 (2005, 2006) are then used to evaluate the derived correlations. Comparisons between measured and calculated values of H have been performed. It is indicated that, the Sen and Bulut and Büyükalaca models satisfactorily describe the horizontal global solar radiation for Jeddah. All the proposed correlations are found to be able to predict the annual average of daily global solar radiation with excellent accuracy. Therefore, the long term performance of solar energy devices can be estimated.Global solar radiation Regression analysis Meteorological data

Controlling of photoresponse properties of pentacene thin film phototransistors by dielectric layer thickness and channel widths

Organic thin film transistors have recently attracted increasing attention due to some features such as their low production cost, flexibility and possibility of large area. In present review, we report the photoresponse performance of the pentacene thin film transistors including electrodes and dielectric layer thickness. The pentacene transistors having various gate thickness and the various channel widths were fabricated and their electrical characteristics were investigated under dark and white light illuminations. The thickness of gate dielectric layer of the pentacene transistors plays role on the photoresponse of the pentacene transistors. Modification of production parameters of the pentacene organic thin film transistors can be exploited in photosensors based upon organic transistors. It is evaluated that these transistors can be used in two-terminal photodetector applications. © 2013 Elsevier B.V.University of TabukThis study was supported by Tabuk University under projects No. S-0195-1434 and S-0196-1434 . Atuhors thank to Tabuk University for supporting

De novo mutation in the KCNQ1 gene causal to Jervell and Lange-Nielsen syndrome.

Jervell and Lange-Nielsen syndrome (JLNS) is an autosomal recessive disorder, clinically characterized by severe cardiac arrhythmias [due to prolonged QTc interval in electrocardiogram (ECG)] and bilateral sensory neural deafness. Molecular defects causal to JLNS are either homozygous or compound heterozygous mutations, predominantly in the KCNQ1 gene and occasionally in the KCNE1 gene. As the molecular defect is bi-allelic, JLNS patients inherit one pathogenic mutation causal to the disorder from each parent. In this report, we show for the first time that such a disorder could also occur due to a spontaneous de novo mutation in the affected individual, not inherited from the parent, which makes this case unique unlike the previously reported JLNS cases

The Prevalence of Antibiotic-Resistant Bacterial Nasal Carriage at a Saudi University Hospital

<p>The objective of our study was to identify the nasal carriage of common and novel nosocomial pathogens that may occur in the patients of an Intensive Care Unit (ICU) of a Saudi university hospital.</p><p>Nasal swabs taken from 95 randomly selected patients were used as clinical specimens, which  were plated onto blood, MacConkey, and chocolate agars. Thereafter, these pathogens were grown, they were identified using Matrix Assisted Laser Desorption Ionization-Time of Flight mass spectrometry (MALDI-TOF MS) and tested for antimicrobial-susceptibility using an automated VITEK2 system (bioMerieux).</p><p>Pseudomonas aeruginosa was the most prevalent species, accounting for 16 (16.84%) isolates. Gentamicin was the most effective antibiotic against Multidrug-Resistant (MDR) Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumonia. Trimethroprim-sulfamethoxazole A was the least effective antibiotic against K. pneumonia.</p><p>In conclusion, the AMR bacteria isolated from the nasal swabs showed different resistance patterns compared to those in other studies in Saudi Arabia. This data could assist healthcare practitioners to prescribe the most effective and appropriate antibiotics, and it also provides information upon which infection control plans, which are critical for outbreak prevention, can be based.</p&gt

Evaluation of health care services provided for older adults in primary health care centers and its internal environment. A step towards age-friendly health centers

Objectives: to evaluate the health care services provided for older adults by primary health care centers (PHCCs) in Riyadh, Kingdom of Saudi Arabia (KSA), and the ease of use of these centers by older adults. Methods: between October 2013 and January 2014, we conducted a descriptive cross-sectional study of 15 randomly selected PHCCs in Riyadh City, KSA. The evaluation focused on basic indicators of clinical services offered and factors indicative of the ease of use of the centers by older adults. Evaluations were based upon the age-friendly PHCCs toolkit of the World Health Organization. Results: coverage of basic health assessments (such as blood pressure, diabetes, and blood cholesterol) was generally good. However, fewer than half of the PHCCs offered annual comprehensive screening for the common age-related conditions. There was no screening for cancer. Counseling on improving lifestyle was provided by most centers. However, there was no standard protocol for counseling. Coverage of common vaccinations was poor. The layout of most PHCCs and their signage were good, except for lack of Braille signage. There may be issues of access of older adults to PHCCs through lack of public transport, limited parking opportunities, the presence of steps, ramps, and internal stairs, and the lack of handrails. Conclusions: clinical services and the internal environment of PHCCs can be improved. The data will be useful for health-policy makers to improve PHCCs to be more age-friendl

Effect of ethylene carbonate as a plasticizer on CuI/PVA nanocomposite: Structure, optical and electrical properties

Layers of ethylene carbonate (EC) modified CuI/PVA polymer composites were prepared by growth of CuI nano-particles in an aqueous solution of PVA followed by casting at room temperature. The structural, thermal, optical, electrical and di-electrical characterization of polymer composites was investigated using different techniques. These investigations confirm the growth of CuI nano-particles and reduction of PVA crystallinity by increasing ethylene carbonate concentration. These results show that energy band gap and bulk conductivity increase while activation energy reduces with the increase of EC concentration in the composite. Moreover, the variation of the dielectric permittivity and dielectric loss with EC content are found to obey Debye dispersion relations