143 research outputs found

    Groundwater studies in arid areas in Egypt using LANDSAT satellite images

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    Various features are interpreted which have strong bearing on groundwater in the arid environment. These include the nature of geological and lithologic units, structural lineaments, present and old drainage systems, distribution and form of water pools, geomorphologic units, weathering surfaces and other weathering phenomena, desert soils, sand dunes and dune sand accumulations, growths of natural vegetation and agriculture, and salt crusts and other expressions of salinization. There are many impressive examples which illustrate the significance of satellite image interpretation on the regional conditions of groundwater which could be traced and interconnected over several tens or even several hundreds of kilometers. This is especially true in the northern Western Desert of Egypt where ground water issuing from deep strata comes to the surface along ENE-WSW and ESE-WNW fault lines and fracture systems. Another striking example is illustrated by the occurrence of fresh to brackish groundwater on the Mediterranean Sea Coastal Zone of the Western Desert where the groundwater is found in the form of lenses floating on the saline sea water

    Application of LANDSAT satellite imagery for iron ore prospecting in the Western Desert of Egypt

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    Prospecting for iron ore occurrences was conducted by the Remote Sensing Center in Bahariya Oasis-El Faiyum area covering some 100,000 km squared in the Western Desert of Egypt. LANDSAT-1 satellite images were utilized as the main tool in the regional prospecting of the iron ores. The delineation of the geological units and geological structure through the interpretation of the images corroborated by field observations and structural analysis led to the discovery of new iron ore occurrences in the area of investigation

    Parameter Estimation for the New Weibull Pareto Distribution under Type II Censored Samples

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    In this paper, parameters estimation under type II censored samples and the corresponding variance covariance matrix for the new WeibullndashPareto distribution are obtained. Nasiru and Luguterah (2015) Results may be considered as a special case from present results. An illustrative example is carried out by using a simulated data

    Morphological Variation between Life and Death Gastropod Populations in the Nile Delta: A Pollution-Induced Evolution

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    Wetland ecosystems of the Nile Delta face severe threats due to natural climatic changes and anthropogenic activities. Life and death assemblage comparisons can be implemented as a historical record to detect anthropogenic-induced environmental changes in the past few decades. A geometric morphometric approach was applied to quantify the pollution-induced morphological variation between life and death populations of the gastropod Melanoides tuberculata. The results indicated that life populations differ significantly from the death ones, where the first tend to be much smaller, more globular, and with a depressed aperture and whorl section. In addition, the phenetic diversity of the life populations was also decreased, and the allometric growth was shifted. These morphological changes in the life populations are well-known adaptations for reducing the cost of shell maintenance in polluted water. No distinct morphospace was found between life populations from different habitats, suggesting that habitats have no significant role in the current pollution-induced evolution.This work is funded by the Researchers Supporting Project number (RSP2023R455), King Saud University, Riyadh, Saudi Arabia

    Impact of Vancomycin on sarA-Mediated Biofilm Formation: Role in Persistent Endovascular Infections Due to Methicillin-Resistant Staphylococcus aureus

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    Background. Staphylococcus aureus is the most common cause of endovascular infections. The staphylococcal accessory regulator A locus (sarA) is a major virulence determinant that may potentially impact methicillin-resistant S. aureus (MRSA) persistence in such infections via its influence on biofilm formation. Methods. Two healthcare-associated MRSA isolates from patients with persistent bacteremia and 2 prototypical community-acquired MRSA strains, as well as their respective isogenic sarA mutants, were studied for in vitro biofilm formation, fibronectin-binding capacity, autolysis, and protease and nuclease activities. These assays were done in the presence or absence of sub-minimum inhibitory concentrations (MICs) of vancomycin. In addition, these strain pairs were compared for intrinsic virulence and responses to vancomycin therapy in experimental infective endocarditis, a prototypical biofilm model. Results. All sarA mutants displayed significantly reduced biofilm formation and binding to fibronectin but increased protease production in vitro, compared with their respective parental strains. Interestingly, exposure to sub-MICs of vancomycin significantly promoted biofilm formation and fibronectin-binding in parental strains but not in sarA mutants. In addition, all sarA mutants became exquisitely susceptible to vancomycin therapy, compared with their respective parental strains, in the infective endocarditis model. Conclusions. These observations suggest that sarA activation is important in persistent MRSA endovascular infection, potentially in the setting of biofilm formatio

    Efavirenz inhibits the human ether-a-go-go related current (hERG) and induces QT interval prolongation in CYP2B6*6*6 allele carriers

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    Background Efavirenz (EFV) has been associated with torsade de pointes despite marginal QT interval lengthening. Since EFV is metabolized by the cytochrome P450 (CYP) 2B6 enzyme, we hypothesized that EFV would lengthen the rate-corrected QT (QTcF) interval in carriers of the CYP2B6*6 decreased functional allele. Objective The primary objective of this study was to evaluate EFV-associated QT interval changes with regard to CYP2B6 genotype and to explore mechanisms of QT interval lengthening. Methods EFV was administered to healthy volunteers (n=57) as a single 600 mg dose followed by multiple doses to steady-state. Subjects were genotyped for known CYP2B6 alleles and ECGs and EFV plasma concentrations were obtained serially. Whole-cell, voltage-clamp experiments were performed on cells stably expressing hERG and exposed to EFV in the presence and absence of CYP2B6 expression. Results EFV demonstrated a gene-dose effect and exceeded the FDA criteria for QTcF interval prolongation in CYP2B6*6/*6 carriers. The largest mean time-matched differences ΔΔQTcF were observed at 6 hrs (14 ms; 95% CI [1; 27]), 12 hrs (18 ms; 95% CI [−4; 40] and 18 hrs (6 ms; 95% CI [−1; 14]) in the CYP2B6*6/*6 genotype. EFV concentrations exceeding 0.4 µg/mL significantly inhibited outward hERG tail currents (P<0.05). Conclusions This study demonstrates that homozygous carriers of CYP2B6*6 allele may be at increased risk for EFV-induced QTcF interval prolongation via inhibition of hERG

    Trans-species transmission of Brucellae among ruminants hampering brucellosis control efforts in Egypt

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    Aims: This study aimed to identify the genotypic fingerprinting of Brucella melitensis biovar 3 isolates from ruminants in Kafr El-Sheikh, Egypt, to compare with other peers globally and to highlight the epidemiology and potential causes of brucellosis control failure.Kafr El-Sheikh University, Grant/Award Number: KFSU-3-13-04Depto. de Sanidad AnimalCentro de Vigilancia Sanitaria Veterinaria (VISAVET)TRUEpu

    Parental awareness regarding pediatric antibiotic use in Madinah, Saudi Arabia

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    Purpose: To determine the level of awareness of antibiotic use in children in Madinah, Saudi Arabia, and to identify factors associated with parental decisions regarding it. Methods: Using a multiple-choice-question-based questionnaire survey, 1256 forms were distributed to visitors of major shopping malls in Madinah City to obtain socio-demographic and antibiotics knowledgebased data from October 2017 to January 2018. Differences in scores between and within groups on knowledge of parents about antibiotics were determined. Results: Most participants (67 %) had good basic knowledge of antibiotics: 69 and 40 % of respondents were aware of their side effects and antibacterial resistance, respectively. Participants in high age groups (&gt; 46 years old) have a significantly higher mean knowledge score (55.4 ± 20.1, p &lt; 0.05) than those in younger groups. Educational status increased the mean knowledge score by approximately 60 %, with the most educated group having a mean score of 61.2 ± 16.4 (p &lt; 0.05). Conclusion: These results reveal the importance of awareness campaigns on antibiotic use and the role of healthcare professionals in the education of patients and parents on correct use of antibiotics, as well as the significance of antibacterial resistance. Keywords: Antibiotics misuse, Pediatrics, Patient education, Antibacterial resistanc

    Impact of exposure of methicillin-resistant Staphylococcus aureus to polyhexanide in vitro and in vivo.

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    Staphylococcus aureus (MRSA) resistant to decolonization agents such as mupirocin and chlorhexidine increase the need to develop alternative decolonization molecules. The absence of reported adverse reactions and bacterial resistance to polyhexanide makes it an excellent choice as topical antiseptic. In the present study we evaluated the in vitro and in vivo capacity to generate strains with reduced polyhexanide susceptibility and cross-resistance with chlorhexidine and/or antibiotics currently used in clinic. Here we report the in vitro emergence of reduced-susceptibility to polyhexanide by prolonged-stepwise exposure to low concentrations in broth culture. Reduced susceptibility to polyhexanide was associated with genomic changes in the mprF and purR genes, and with concomitant decreased susceptibility to daptomycin and other cell-wall active antibiotics. However, the in vitro emergence of reduced-susceptibility to polyhexanide did not result in cross-resistance to chlorhexidine antiseptic. During in vivo polyhexanide clinical decolonization treatment, neither polyhexanide reduced-susceptibility nor chlorhexidine cross-resistance were observed. Together, these observations suggest that polyhexanide could be used safely for decolonisation of carriers of chlorhexidine-resistant S. aureus strains but highlight the need for careful use of polyhexanide at low antiseptic concentrations
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