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Plant assemblage and diversity variation with human disturbances in coastal habitats of the western Arabian Gulf

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Journal of Arid Land 2016年第5期8卷 787-798页

作者： Raafat H abd el-WAHAB Botany Department Faculty of ScienceSuez Canal University Science Department Faculty of Basic EducationPublic Authority for Applied Education and Training

Knowledge about plant diversity along disturbance gradients is essential for conservation and management of fragmented coastal *** study examined the effects of human disturbance intensity in coastal habitats of Kuwait on diversity,composition,identity and assemblage of vascular plant *** survey data from 113 plots （5m×5m each） were randomly selected in 51 sites at coastal fragmented habitats at three levels of disturbance intensities （high,moderate and low） and were statistically *** results revealed that about 76% of the recorded species are considered threatened species in Kuwait,most of which are being lost in high disturbed *** led to the dominance of Zygophyllum qatarense,Cornulaca aucheri and Salsola imbricata,which are species of disturbance ***,total plant cover and species diversity were higher in moderate and low disturbed habitats than in high disturbed *** diversity between high and low disturbed habitats was higher than either between high and moderate,or between moderate and low disturbed *** analyses showed statistically significant differences in composition of plant assemblages,which indicate high beta diversity between the habitat *** urbanization and industrialization are among the most serious threats that contribute to declines in biological diversity and rapid fragmentation of coastal habitats in *** protective enclosures in the disturbed habitats,planting endangered and vulnerable species,and establishing a natural reserve at Nuwaiseeb are recommended conservation actions to avoid loss of the fragmented coastal habitats and to facilitate restoration of native plants.

关键词： plant diversity disturbance gradient threatened species habitat fragmentation coastal habitat salt marsh restoration

Effect of Conductive Fillers on the Cyclic Stress-Strain and Nano-Scale Free Volume Properties of Silicone Rubber

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Chinese Journal of Polymer Science 2014年第5期32卷 558-567页

作者： M.H.abd-el Salam S.el-Gamal M.Mohsen D.M.abd el-Maqsoud Physics Department Faculty of Education Ain Shams University Physics Department Faculty of Science Ain Shams University

The effect of carbon black （CB） and graphite （G） powders on the macroscopic and nano-scale free volume properties of silicone rubber based on poly（di-methylsiloxane）（PDMS） was studied through thermal and cyclic mechanical measurements, as well as with positron annihilation lifetime spectroscopy （PALS）. The melting temperature of the composites （Tm） and the endothermic enthalpy of melting （ΔHm） were estimated by differential scanning calorimetry （DSC）. Tm and the degree of crystallinity （χc） of PDMS composites were found to decrease with increasing the CB content. This can be explained due to the increase in physical cross-linking which results in a decrease in the crystallite thickness. Besides, χc was found to be dependent on the filler type. Cyclic stress-strain behavior of PDMS loaded with different contents of filler has been studied. Mullins ratio （RM） was found to be dependent on the filler type and content. It was found that, RM increases with increasing the filler content due to the increase in physical cross-linking which results in a decrease in the size of free volume, as observed through a decrease of the o-Ps lifetime τ3 measured by PALS. Moreover, the hysteresis in PDMS-CB composites was more pronounced than in PDMS-G composites. Furthermore, a correlation was established between the free volume Vf and the mechanical properties of PDMS composites containing different fillers. A negative correlation was observed between Vf and RM.

关键词： Positron annihilation Positronium Free volume Si-rubber Composite Cyclic mechanical properties.

Magnetoresistive properties of Ni-doped La_(0.7)Sr_(0.3)MnO_3 manganites

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Rare Metals 2016年第7期35卷 551-558页

作者： Ahmed Mohamed Ahmed abd el-Moez Ahmed Mohamed Medhat abdelrady abdellateef Hassan Ahmed abd el-Ghanny Physics Department Faculty of ScienceSohag University

Lao.7Sr0.3Mnl_xNixO3 （x = 0, 0.025, 0.050 and 0.075） ceramics were prepared by the conventional solid-state reaction method. The partial substitution of Mn by Ni2＋ leads to a decrease in cell volume as well as a structural transition from the rhombohedral to the orthorhombic structure. Ni2＋ doping increases the electrical resistivity, decreases the semiconductor-metal transition temperature （Tms） and relatively enhances the room temperature magnetoresistance （MR）, especially in x = 0.025 and around Tins. With respect to conduction mechanism, the small polaron hopping （SPH） and the variable range hopping （VRH） models were used to ex- amine conduction in the semiconducting region.

关键词： Manganites X-ray diffraction Structure electrical resistivity Magnetoresistance

Neoproterozoic Tectonic Events of Egypt

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Acta Geologica Sinica(English Edition) 2021年第4期95卷 1366-1405页

作者： Mohamed abd el-WAHED Zakaria HAMIMI Geology Department Faculty of ScienceTanta UniversityTanta 31527Egypt Department of Geology Faulty of ScienceBen ha UniversityBenha 13518Egypt

The Egyptian Nubian Shield(ENS)represents the northwestern part of the Arabian-Nubian Shield and the northern extension of the East African *** ENS is regarded as being formed due to northward-directed escape *** is characterized by mild accretion and suture zones dominated by major strike-slip zones with a commonly sinistral sense of movement;some shear zones display a dextral sense of *** is dominated by gneisses and migmatites in the south,arc volcaniclastic metasediments and highly dismembered ophiolites in the central parts,whereas its northern part is dominated by late-to post-tectonic *** southern Sinai,the Neoproterozoic rocks are grouped into four complexes,namely Feiran–Solaf,Sa’al–Zaghra,Kid and *** ENS ophiolites were formed between 730–750 Ma,mainly in a supra-subduction zone *** ENS has undergone a Neoproterozoic deformation history involving three successive phases:(1)Early N–S shortening phase(D1),(2)Syn-accretionary phase(D2)and(3)Post-accretionary phase(D3).The initial island-arc stage(780–730 Ma)is a N–S shortening phase initiated by collision between the Eastern Desert tectonic terrane to the north with both the Gebeit and Gabgaba terranes to the south(830–720 Ma).During the arc-splitting and back-arc spreading stage(730–620),voluminous syn-tectonic granitoids intruded into the ENS(750–610 Ma).The E–W-directed compressional/transpressional phase(620–450 Ma)led to the overall uplift of the central part of the ENS and consequently the development and exhumation of the core complexes in oblique convergent *** E–W intense shortening deformation resulted also in the formation of NW-and NE-striking sinistral and dextral strike-slip shear zones,*** latest periods of the E–W-directed compressional/transpressional regime were characterized by deposition of the molasse-type Hammamat Sediments unconformably over the Dokhan Volcanics,or interbedded with *** combined thrusting,folding and sin

关键词： Neoproterozoic deformation N–S shortening syn-accretionary phase post-accretionary phase Egyptian Nubian Shield

Radionuclides measurements and mineralogical studies on beach sands, East Rosetta Estuary, Egypt

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Chinese Journal Of Geochemistry 2013年第2期32卷 146-156页

作者： abd el Wahab M. el Nahas H.A. Physics Department Faculty of Women for Arts Science and Education Ain Shams University Cairo P.O 11757 Egypt Nuclear Materials Authority Cairo P.O. Box 530 Egypt

Radiometric measurements were carried out for the beach sands from East Rosetta estuary to determine the activity concentrations of 238 U, 226 Ra, 232 Th, and 40 K, using a Hyper Pure Germanium spectrometer, to estimate the dose rates and radiation hazard indices. The average specific activities are 778.20 Bq/kg for 238 U; 646.89 Bq/kg for 226 Ra; 621.92 and 627.85 Bq/kg for the 222 Rn daughters 214 Pb and 214 Bi respectively. The average specific activity of 232 Th is 1510.25 Bq/kg, while the calculated specific activity for 40 K has an average of 8.41 Bq/kg. The average specific activity of 235 U is 38.61 Bq/kg. The average absorbed dose rate is 1211.36 nGy/h, 20 times higher than the estimated average global primordial radiation of 60 nGy/h and 6 times higher than that of the world range (10-200 nGy/h). The radium equivalent (Ra eq ) values are from 6 to 9 times the recommended value. The internal and external hazard indices (H int , H ex ) indicate that their values are from 6 to 11 times the permissible values of these indices. These higher values may be due to the presence of economic heavy minerals containing radionuclides as zircon and monazite as well as some trace minerals, thorite and uranothorite. The mineralogical study indicates the beach sands contain heavy minerals, zircon, monazite, rutile, ilmenite, leucoxene, magnetite and garnet. The average abundance of zircon is 0.175 wt% ranging from 0.125 wt% to 0.239 wt%, while it is 0.004wt% ranging from 0.001 wt% to 0.007 wt% for monazite. The average abundance is 0.087 wt% for rutile; 2.029 wt% for ilmenite; 1.084 wt% for magnetite; 0.384 wt% for leucoxene and 0.295 wt% for garnet.

关键词：放射性核素海滩砂矿物学核素测量河口平均丰度埃及辐射测量

Comparison of bacterial community structures in two systems of a sewage treatment plant using PCR-DGGE analysis

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Journal of Environmental Sciences 2011年第12期23卷 2049-2054页

作者： abd el-Latif Hesham Rong Qi Min Yang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Genetics Department Faculty of Agriculture Assiut University Assiut Egypt

The combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis （DGGE） analysis was used to reveal the compositions and dynamics of bacterial communities in a sewage treatment plant with two systems, i.e., an anoxic- anaerobic-aerobic system （inverted A2O） and an anaerobic-anoxic-aerobic one （conventional A2O） over a period from February to July 2009, during which both systems experienced serious sludge bulking problems. The DGGE patterns showed that there were many common bands in both systems, suggesting the high similarity of bacterial communities of the two systems. Meanwhile, the moving window correlation analysis showed that the two systems experienced different microbial community structure changes during the period, which might be related with the different situations of the occurrence and disappearance of sludge bulking, as being reflected by sludge volume index （SVI） values. Major bands of DGGE patterns of sludge samples were further sequenced. Phylogenetic affiliation indicated that the majority of the sequences obtained were affiliated with Actinobacteria, Firmicutes, Bacteroidetes/Chlorobi group and α- and β-Proteobacteria. Two sequences showed high similarities to typical filamentous bacteria Microthrix parvicella and Nostocoida limicola I, indicating that these bacterial species have been involved in the sludge bulking problems.

关键词： PCR-DGGE bacterial community activated sludge sludge bulking sewage treatment plant

Biochemical Liver Functions and Molecular Identification of Fasciola hepatica from Experimentally Infected Rat Model

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Open Journal of Animal Sciences 2024年第2期14卷 88-100页

作者： Omnia M. Kandil Emad B. Ata Margarita P. Gabrashanska Hatem A. Shalaby Tamer H. abd el-Aziz Noha M. F. Hassan Soad M. Nasr Mohamed A. Helal Ebtesam M. Al-Olayan Department of Parasitology & Animal Diseases Veterinary Research Institute National Research Centre Giza Egypt Institute of Experimental Morphology Pathology and Anthropology with Museum Bulgarian Academy of Sciences Sofia Bulgaria Department of Zoology Collage of Science King Saud University Riyadh Saudi Arabia

The current study was performed to evaluate the liver function status as well as molecular characterization of the recovered worms in rats experimentally infected with F. hepatica. Sixteen male Wister rats aged 30 days were randomly allocated into two groups (n = 8). The first group was infected orally with 15 viable encysted metacercaria of F. hepatica per animal. The other group was kept non-infected (control group). At zero time (before infection), the 2nd, 4th, 6th, 8th, 10th, 12th and 14th weeks post-infection (WPI), blood and serum samples were collected via puncture of retro-orbital plexus of veins from each rat. Serum enzyme level (AST and ALT) and total protein were measured, and the serum protein profile was carried out using agarose gel electrophoresis. During the period of the experiment, serum ALT and AST activities and serum total globulins significantly increased while serum total proteins and albumin markedly decreased in the infected group. On the 14th WPI, the data of the electropherogram showed that globulin fractions (α1-, β- and γ-globulin) levels were significantly increased while α2-globulin was markedly decreased in the infected group. The molecular analysis confirmed the amplification of the ITS1, ITS2 and NDI genes of F. hepatica recovered from the infected liver of rats with amplicon sizes of 630, 510 and 560 bp, respectively. Sequencing of the amplified ITS gene resulted in the determination of 3 strains (PP108836, PP108837, and PP108838). Also, analysis of the ITS2 gene resulted in obtaining 3 isolates under the accession numbers (PP109065, PP109066, and PP109067). In conclusion, fasciolosis in the rat model is suitable for routine experimental infections and caused a pronounced liver dysfunction with discharging of the Fasciola eggs in the faeces and the development of adult stages in the bile ducts. Furthermore, molecular techniques are a sensitive

关键词： Fasciola hepatica Liver Functions Serum Enzymes Serum Protein electrophoresis Molecular Characterization

Entropy Generation for Flow and Heat Transfer of Sisko-Fluid Over an Exponentially Stretching Surface

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Computers, Materials & Continua 2020年第1期62卷 37-59页

作者： Mohamed abd el-Aziz A.M.Aly Department of Mathematics Faculty of ScienceKing Khalid UniversityAbha61411Saudi Arabia Department of Mathematics Faculty of ScienceHelwan UniversityHelwan-Cairo11795Egypt Department of Mathematics Faculty of ScienceSouth Valley UniversityQena83523Egypt

In the present study,the effects of the magnetic field on the entropy generation during fluid flow and heat transfer of a Sisko-fluid over an exponentially stretching surface are *** similarity transformations are used to transfer the governing partial differential equations into a set of nonlinear-coupled ordinary differential ***-Kutta-Fehlberg method is used to solve the governing *** effects of magnetic field parameter,local slip parameterλ,generalized Biot numberγ,Sisko fluid material parameter,Eckert number Ec,Prandtl number Pr and Brinkman number Br at two values of power law index on the velocity,temperature,local entropy generation number N_(G) and Bejan number Be are ***,the tabular forms for local skin friction coefficient and local Nusselt number under the effects of the physical parameters are *** current results are helpful in checking the entropy generation for *** is found that,an extra magnetic field parameter makes higher Lorentz force that suppresses the *** shear thinning fluids(nelocity *** entropy generation number is more for larger generalized Biot number,magnetic field parameter and Brinkman *** local skin friction coefficient increases as magnetic field parameter and material parameter are increase and it decreases as local slip parameter *** local Nusselt number decreases as magnetic field parameter,local slip parameter and Eckert number are increase,while it increases as material parameter,generalized Biot number and Prandtl number are increase.

关键词： Boundary layer entropy generation exponentially stretching surface magnetic field sisko-fluid

MHD Boundary Layer Flow of a Power-Law Nanofluid Containing Gyrotactic Microorganisms Over an Exponentially Stretching Surface

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Computers, Materials & Continua 2020年第2期62卷 525-549页

This study focusses on the numerical investigations of boundary layer flow for magnetohydrodynamic(MHD)and a power-law nanofluid containing gyrotactic microorganisms on an exponentially stretching surface with zero nanoparticle mass flux and convective *** nonlinear system of the governing equations is transformed and solved by Runge-Kutta-Fehlberg *** impacts of the transverse magnetic field,bioconvection parameters,Lewis number,nanofluid parameters,Prandtl number and power-law index on the velocity,temperature,nanoparticle volume fraction,density of motile microorganism profiles is *** addition,the impacts of these parameters on local skin-friction coefficient,local Nusselt,local Sherwood numbers and local density number of the motile microorganisms are *** results reveal that the power law index is considered an important factor in this *** to neglecting the buoyancy force term,the bioconvection and nanofluid parameters have slight effects on the velocity *** resultant Lorentz force,from increasing the magnetic field parameter,try to decrease the velocity profiles and increase the rescaled density of motile microorganisms,temperature and nanoparticle volume fraction ***,an augmentation of power-law index drops the reduced local skin-friction and reduced Sherwood number,while it increases reduced Nusselt number and reduced local density number of motile microorganisms.

关键词： Bioconvection gyrotactic microorganisms magnetohydrodynamic nanofluid boundary layer power-law