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Evaluation of phosphorus bioavailability in el mex Bay and Lake mariut sediments

International Journal of Sediment Research 2017年第3期32卷 432-441页

作者： Naglaa F.Soliman gehan m.el zokm mohamed A.Okbah Department of Environmental Studies Institute of Graduate Studies and Research University of Alexandria National Institute of Oceanography and Fisheries

Phosphorus(P) fractions and their bioavailability in the sediments from.el mex Bay and Lake mariut in Egypt were investigated using different chemical extraction methods. Sodium bicarbonate(NaHC03)extractable P(Olsen-P) was the largest fraction(14.42%), followed by algal available P(AAP)(3.56%),water soluble P(WSP)(0.79%), and readily desorbable P(RDP)(0.06%) for el mex Bay. While AAP contributed 9.94% to total P in sediments from Lake mariut, Olsen-P 8.53%, WSP 4.11%, and RDP 0.92%.Summation of the bioavailable P fractions didn’t exceed the sediment quality guidelines, and, therefore, P doesn’t represent a danger to marine organisms. Correlation coefficients showed that no apparent relations between total P(TP) and iron(Fe), aluminum(Al), and calcium(Ca) in the sediments. Furthermore, Fe:P ratio was less than 15 indicting that there was not enough Fe in surface sediments to bind to P at most of the sampling sites. The positive correlation between TP and organic matter(Om) for Lake mariut and el mex Bay sediments indicated that the organic matter content of the sediment was a useful predictor of the total phosphorus content. Data from this study constitute a baseline of phosphorus bioavailability in sediments from.el mex Bay and Lake mariut and could be used as a reference for future studies on the changes of bioavailable and residual phosphorus fractions over time.

关键词： Phosphorus bioavailability Sediments el mex Bay Lake mariut

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Adipose tissue-derived mesenchymal stem cells and chitosan/poly(vinyl alcohol)nanofibrous scaffolds for cartilage tissue engineering

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Cell Regeneration 2020年第1期9卷 62-73页

作者： Ghada Nour-eldeen mazen Abdel-Rasheed Amira m.el-Rafei Osama Azmy gehan T.el-Bassyouni molecular Genetics and Enzymology Department National Research CentreDokkiCairo 12622Egypt Stem Cell Research group Medical Research Centre of ExcellenceNational Research CentreCairo 12622Egypt Reproductive Health Research Department National Research Centre33 El-Buhouth StDokkiCairo 12622Egypt Refractories Ceramics and Building Materials DepartmentNational Research CentreDokkiCairo 12622Egypt

Osteoarthritis(OA)has been defined as a chronic inflammatory joint disease characterized by progressive articular cartilage *** growing interest in regenerative medicine,using cell therapy and tissue engineering,where cellular components in combination with engineered scaffolds and bioactive materials were used to induce functional tissue *** the present study,nanofibrous scaffold based on chitosan(CS)/poly(vinyl alcohol)(PVA)were used to develop biologically functionalized biomaterial to mimic the extracellular matrix,allowing the human adipose tissue derived mesenchymal stem cells(ADSCs)to proliferate and differentiate to chondrogenic *** morphology of the nanofibrous mat was examined using field emission scanning electron microscope(FE/SEm).The characteristic functional groups and the nature of the chemical bonds between atoms were evaluated using Fourier transform infrared spectroscopy(FTIR)*** of the seeded cells was morphologically evaluated by scanning electron microscopy and by flow cytometry for the expression of the stem cell surface *** differentiation potential was verified after chondrogenic induction by analyzing the expression of chondrogenic marker genes using real-time(RT PCR).Current study suggest significant potential for the use of ADSCs with the nanofibrous scaffolds in improving the osteoarthritis pathology.

关键词： Adipose tissue mesenchymal stem cells Nanofibrous scaffolds Osteoarthritis Cartilage tissue engineering

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Influence of host age and host deprivation on longevity, egg load dynamics and oviposition rate in microplitis rufiventris

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Insect Science 2007年第6期14卷 485-495页

作者： ESmAT mOHAmED HEGAZI gehan mOHAmED ABD el-AZIZ AHmED YOUSEF el-SHAZLY WEDAD EmAm KHAFAG Department of Entomology Faculty of Agriculture University of Alexandria Plant Protection Research Institute Sabahia Alexandria Egypt

Adult size, longevity, egg load dynamics and oviposition ofmicroplitis rufiventris Kok. which began their development in the first, second, third （preferred hosts） or fourth （non-preferred hosts） instar larvae of Spodoptera littoralis （Boisd.） were studied. The parasitoid size was largely determined by the initial host size at parasitism. Non-ovipositing females derived from older hosts lived for longer periods than those derived from younger ones. However, the ovipositing females, irrespective of their size, lived for almost the same periods. At emergence, the oviducts of adult females contain a significant amount of mature eggs available for oviposition for a few hours on eclosion day. Egg load increases during the early phase of adult life. The amount of additional mature eggs and rate of egg maturation per hour was greater for wasps derived from preferred hosts compared with those in females derived from non-preferred hosts. The pattern of egg production in m. rufiventris females depended on the availability of hosts for parasitization. Host-deprived females depleted the egg complement with aging; the longer the host deprivation, the lower the oviduct egg load. marked reduction in both realized or potential fecundity of host-deprived females was observed following host availability. Host privation for more than 3 days induced a marked deficit fecundity pattern through the female＇ s life. The realized fecundity was determined by the interaction among host availability, the number of eggs that are matured over the female＇ s life span, oviposition rate and host size from which the female was derived. These results suggest that：（i） m. rufiventris wasp is a weak synovigenic species; （ii） the maturation of additional eggs is inhibited once the maximum oviduct egg load is reached; （iii） the egg load of the newly emerged female is significantly less than the realized fecundity; and （iv） because m. rufiventris females oviposit fewer eggs when they begin depleting their

关键词： aging egg production host privation longevity microplitis rufiventris,oviposition Spodoptera littoralis wasp size

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Nutrient Fluxes and Sediments Composition in el mex Bay and Surround Drains, Alexandria, Egypt

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American Journal of Analytical Chemistry 2015年第6期6卷 513-527页

作者： mohamed Attia Shreadah mamdouh Saad masoud Abdel-Rhman mosaad Khattab gehan mohamed el zokm National Institute of Oceanography and Fisheries Alexandria Egypt Faculty of Science Alexandria University Alexandria Egypt Faculty of Science Al-Azhar University Cairo Egypt

The regeneration of pore water (PW) nutrients was investigated and the contribution of benthic nutrient fluxes to the overlying bottom water (BW) was examined. Dissolved inorganic nutrients (NO-2, NO-3, PO3-4 and SIO4-4) were measured in PW and BW in el mex Bay and surround drains during spring 2010. Nutrient concentrations gradiance in PW with overlying seawater were evaluated according to Fick’s Law. Average inorganic nutrient fluxes were estimated using the pore water gradient concentration across the sediment-water interface. Calculated nutrient fluxes had averages of ﹣7.24, ﹣1.36, ﹣7.86 and ﹣1.33 in el mex Bay. Additionally, the fluxes in the drains were ﹣34.39, ﹣32.28, ﹣53.20 and ﹣117.6 mg·m﹣2·day﹣1 for NO-3, NO-2, PO3-4 and SIO4-4, respectively. mineralogical studies of sediment samples by using IR, X-ray analysis were carried out to identify the chemical structure of sediments. The results revealed that calcite, aragonite and quartz are the dominant minerals. On the other hand, differential thermal analysis (DTA) was used to evaluate and discuss different kinetic parameters such as Ea#, ΔG#, ΔH#, ΔS#, Z and Tm support the view of the extra stability of these sediments.

关键词： Nutrient Fluxes IR-X-Ray-DTA Sediments el mex Bay Alexandria Egypt

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Hierarchical TiO_2/ZnO Nanostructure as Novel Non-precious electrocatalyst for Ethanol electrooxidation

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Journal of materials Science & Technology 2015年第1期31卷 97-105页

作者： gehan m.K.Tolba Nasser A.m.Barakat A.m.Bastaweesy E.A.Ashour Wael Abdelmoez mohamed H.el-Newehy Salem S.Al-Deyab Hak Yong Kim Organic materials and Fiber Engineering Department Chonbuk National University Chemical Engineering Department Faculty of EngineeringMinia University BioNanosystem Department Chonbuk National University Department of Chemistry College of ScienceKing Saud University

metal oxides have a higher chemical stability in comparison to metals,so they can be utilized as electrocatalysts if the activity could be *** the composition,the morphology of the nanostructures has a considerable impact on the electrocatalytic *** this work,zinc oxide nano branches-attached titanium dioxide nanofibers were investigated as an economic and stable catalyst for ethanol electrooxidation in the alkaline *** introduced material has been synthesized by electrospinning process followed by hydrothermal ***,electrospinning of colloidal solution consisting of titanium isopropoxide,poly（vinyl acetate） and zinc nanoparticles was performed to produce nanofibers embedding solid *** order to produce TiO2nanofibers containing ZnO nanoparticles,the obtained electrospun nanofiber mats were calcined in air at 600 °*** formed ZnO nanoparticles were exploited as seeds to outgrow ZnO branches around the TiO2nanofibers using the hydrothermal technique at sub-critical water conditions in the presence of zinc nitrate and bis-hexamethylene *** morphology of the final product,as well as the electrochemical measurements indicated that zinc nanoparticles content in the original electrospun nanofibers has a significant influence on the electrocatalytic activity as the best performance was observed with the nanofibers synthesized from.electrospun solution containing 0.1 g Zn,and the corresponding current density was 37 mA/***,this study paves a way to titanium dioxide to be exploited to synthesize effective and stable metal oxide-based electrocatalysts.

关键词： Direct ethanol fuel cells electrospinning Nanofibe

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