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Existence and numerical approximation of a solution to frictional contact problem for electro-elastic materials

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 201-219页

作者： Othman Baiz el-Hassan Benkhira Rachid Fakhar University Ibn Zohr Lab.ESERFP of OuarzazateMorocco University Moulay Ismail Faculty of SciencesLaboratory MACSESTMBP 3103Toulal-MeknesMorocco University Sultan Moulay Slimane Laboratory LS2MEPolydisciplary Faculty of Khouribga25000 KhouribgaMorocco

In this paper,a frictional contact problem between an electro-elastic body and an electrically conductive foundation is *** contact is modeled by normal compliance with finite penetration and a version of Coulomb’s law of dry friction in which the coefficient of friction depends on the *** addition,the effects of the electrical conductivity of the foundation are taken into *** model leads to a coupled system of the quasi-variational inequality of the elliptic type for the displacement and the nonlinear variational equation for the electric *** existence of a weak solution is proved by using an abstract result for elliptic variational inequalities and a fixed point ***,a finite element approximation of the problem is *** some regularity conditions,an optimal order error estimate of the approximate solution is ***,a successive iteration technique is used to solve the problem numerically and a convergence result is established.

关键词： piezoelectric material frictional contact variational Inequality fixed point process finite element method error estimation iteration method

Analysis of the Impact of the Blazhko Effect Both on the Van Hoof Effect and Radial Velocity Amplitude in the Star RR Lyr

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Research in Astronomy and Astrophysics 2024年第6期24卷 253-272页

作者： y.el jariri F.L.Sefyani A.Benhida Z.Benkhaldoun K.Kolenberg K.Chafouai A.Habib M.Sabil Observatoire de l'Oukaimeden LPHEAFSSMUniversitéCadi AyyadMarrakech2390Morocco Observatoire de l'Oukaimeden LPHEAFSTGUniversitéCadi AyyadMarrakech549Morocco Département de physique Universitéd'Anvers Avenue Groenenborger 171Anvers2020Belgium LICPM ENSA-BMUniversitéSultan Moulay SlimaneBeni-Mellal23020Morocco

The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating *** this article,we present a study of this phenomenon through the spectra of the brightest pulsating star RR Lyr of RR Lyrae stars recorded for 22 *** based ourselves,on the one hand,on 1268 spectra(41 nights of observation)recorded between the years 1994 and 1997 at the Observatory of Haute Provence(OHP,France)previously observed by Chadid and Gillet,and on the other hand on 1569 spectra(46nights of observation)recorded at our Oukaimeden Observatory(Morocco)between 2015 and *** this study,we have detected information on atmospheric dynamics that had not previously been ***,the Van Hoof effect which results in a clear correlation between the radial velocities of hydrogen and those of the metallic lines has been observed and analyzed at different Blazhko phases.A correlation between the radial velocities of different metallic lines located in the lower atmosphere has been observed as *** the first time,we were able to show that the amplitude of the radial velocity curves deduced from the lines of hydrogen and that of FeⅡ(λ4923.921?)increases toward the minimum of the Blazhko cycle and decreases toward the maximum of the same Blazhko ***,we found that the Van Hoof effect is also modulated by the Blazhko ***,toward the minimum of the Blazhko cycle the Van Hoof effect is more visible and at the maximum of the Blazhko cycle,this effect is *** also observed the temporal evolution of the amplitudes of the radial velocities of the lower and upper *** observed over a long time,we can interpret it as a function of the Blazhko phases.

关键词： stars:atmospheres stars:variables:RR Lyrae shock waves techniques:spectroscopic techniques:radial velocities stars:individual(RR Lyr)

A review on the multi-scaled structures and mechanical/thermal properties of tool steels fabricated by laser powder bed fusion additive manufacturing

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1048-1071页

作者： Huajing Zong Nan Kang Zehao Qin Mohamed el Mansori Arts et Metiers Institute of Technology MSMPHESAM UniversitéChâlons-en-Champagne F-51006France Texas A&M Engineering Experiment Station Institute for Manufacturing SystemsCollege Station TX77843USA

The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds *** appearance of the LPBF makes it possible to design and produce complex conformal cooling channel systems in ***,LPBF-processed tool steels have attracted more and more *** complex thermal history in the LPBF process makes the microstructural characteristics and properties different from those of conventional manufactured tool *** paper provides an overview of LPBF-processed tool steels by describing the physical phenomena,the microstructural characteristics,and the mechanical/thermal properties,including tensile properties,wear resistance,and thermal *** microstructural characteristics are presented through a multiscale perspective,ranging from densification,meso-structure,microstructure,substructure in grains,to ***,a summary of tool steels and their challenges and outlooks are introduced.

关键词： additive manufacturing laser powder bed fusion tool steel multi-scaled structure mechanical properties thermal properties

Classical taxonomy,molecular phylogeny and genetic analysis of the genus Exitianus Ball,1929(Hemiptera:Cicadellidae:Deltocephalinae)from Egypt

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Zoological Systematics 2024年第2期49卷 143-157页

作者： Rabab M.el-Hady Ahmed F.el-Sayed Survey&Taxonomy Department Plant Protection Research InstituteAgriculture Research CentreGizaEgypt Microbial Genetics Department Biotechnology Research InstituteNational Research CentreGizaEgypt Egypt Center for Research and Regenerative Medicine(ECRRM) CairoEgypt

Egyptian species of the leafhopper genus Exitianus Ball,1929,***(St?l,1855),***(Distant,1908),and *** Ross,1968 are ***,morphological descriptions,and a key for their identification are *** this study,we used molecular techniques to confirm morphological identification and detect phylogeny among the three Exitianus *** partial nucleotide sequences of the amplified products obtained were determined by Macrogen *** nucleotide sequences of 28S rDNA and COX genes of the EGy-ARC-9,EGy-ARC-4,and EGy-ARC-5 were determined by Macrogen Korea,blasted into BLAST at the National Center for Biotechnology Information website(NCBI)and compared with those deposited in the GenBank DNA *** results represented the homology percentage between the partial sequences of the 28S rRNA and COX genes from each species and related species obtained from GenBank DNA *** morphological identifications of the three Exitianus species were confirmed by molecular characterization and sequencing of 28S rDNA and COX genes and identified as ***,***,and ***,their sequences of 28srDNA and COX genes were deposited in GenBank with an accession number(LC670610,LC670607,and OQ196105)for 28srDNA gene and(LC775357,LC775358,and LC775359)for the COX gene.

关键词： Auchenorrhyncha Chaismini taxonomic 28S rDNA phylogenetic

The role of polymorphic cytochrome P450 gene(CyP2B6)in B-chronic lymphocytic leukemia(B-CLL)incidence and outcome among Egyptian patients

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Oncology Research 2024年第4期32卷 785-797页

作者： MENNA AL-ADL MAGDy MyOUSSEF AHMED el-SEBAIE SHERIF REFAAT AFAF el-SAID Division of Biochemistry Department of ChemistryFaculty of ScienceMansoura UniversityMansoura35511Egypt Hematology Unit Department of Clinical PathologyFaculty of MedicineMansoura UniversityMansoura35511Egypt Medical Oncology Unit Oncology Center Mansoura UniversityMansoura35511Egypt Department of Genetics Mansoura University Children’s HospitalMansoura35511Egypt

Cytochromes P450(CyPs)play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75%of the total metabolism of commercially available drugs,including *** gene expression and enzyme activity of CyPs are variable between individuals,which subsequently leads to different patterns of susceptibility to carcinogenesis by genotoxic xenobiotics,as well as differences in the efficacy and toxicity of clinically used *** research aimed to examine the presence of the CyP2B6*9 polymorphism and its possible association with the incidence of B-CLL in Egyptian patients,as well as the clinical outcome after receiving cyclophosphamide *** was isolated from whole blood samples of 100 de novo B-CLL cases and also from 100 sex-and age-matched healthy *** presence of the CyP2B6*9(G516T)polymorphism was examined by PCR-based allele specific amplification(ASA).Patients were further indicated for receiving chemotherapy,and then they were followed *** CyP2B6*9 variant indicated a statistically significant higher risk of B-CLL under different genetic models,comprising allelic(T-allele vs.G-allele,OR=4.8,pyclophosphamide chemotherapy,we found that the patients with variant genotypes(GT+TT)were less likely to achieve remission compared to those with the wild-type genotype(GG),with a response percentage of(37.5%vs.83%,respectively).In conclusion,our findings showed that the CyP2B6*9(G516T)polymorphism is associated with B-CLL susceptibility among Egyptian *** variant greatly affected the clinical outcome and can serve as a good therapeutic marker in predicting response to cyclophosphamide treatment.

关键词： B-CLL Xenobiotics Cytochromes P450 CyP2B6

Hematobiochemical and histopathological alterations in Nile Tilapia(Oreochromis niloticus)exposed to ethidium bromide:The protective role of Spirulina platensis

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Aquaculture and Fisheries 2024年第1期9卷 93-103页

作者： Sabreen Abdullah Mervat Naguib Alaa el-Din Salah el-Din Alaa el-Din H.Sayed Zoology Department Faculty of ScienceAswan UniversityAswan81528Egypt Zoology Department Faculty of ScienceAssuit UniversityAssiut71516Egypt

Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its *** study examined the potential protective effects of Spirulina platensis(SP)against the effects of EtBr toxicity in the Nile tilapia(Oreochromis niloticus)*** were divided to five groups,viz.,a control and four treatment groups of low-dose EtBr(10μg/L),low-dose EtBr with SP(10μg/L EtBr+200 mg/L SP),high-dose EtBr(100μg/L),and high-dose EtBr with SP(100μg/L EtBr+200 mg/L SP);the exposure period was 2 *** and high doses of EtBr induced alterations in some hematological,biochemical,and histopathological *** hepatocytes,degenerated area,vacuolated hepatocytes,pyknotic nuclei,constricted and dilated blood sinusoids,and infiltration of inflammatory cells were *** peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP,but it was increased in groups exposed to high doses of EtBr and EtBr with SP,compared with the control *** feeding with SP,most histological and histochemical parameters restored to normal ***,SP may possess the ability to preserve the structural integrity of the hepatic and renal membranes.

关键词： Ethidium bromide Spirulina platensis Oreochromis niloticus Liver Lipid peroxidation

Effects of Moringa oleifera aqueous extract on the growth performance,blood characteristics,and histological features of gills and livers in Nile tilapia

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Aquaculture and Fisheries 2024年第1期9卷 85-92页

作者： Mahamoud A.Emam Ramy M.Shourbela Waleed N.el-Hawarry Seham y.Abo-Kora Fatma Abdel-Monem Gad Ashraf M.Abd el-latif Mahmoud A.O.Dawood Histology Department Faculty of Veterinary MedicineBenha UniversityBenha13511Egypt Department of Animal Husbandry and Animal Wealth Development Faculty of Veterinary MedicineAlexandria UniversityAlexandria22758Egypt Pharmacology Department Faculty of Veterinary MedicineBenha UniversityBenha13511Egypt Clinical Pathology Department Faculty of Veterinary MedicineBenha UniversityBenha13511Egypt Department of Aquatic Animal Diseases and Management Faculty of Veterinary MedicineBenha UniversityBenha13511Egypt Animal Production Department Faculty of AgricultureKafrelsheikh UniversityKafr El-Sheikh33511Egypt The Center for Applied Research on the Environment and Sustainability The American University in CairoCairo11835Egypt

Moringa oleifera is well known as a highly nutritious plant and a water purifier in fish *** fish has many impressive qualities making them very suitable for ***,this study aimed to evaluate the effect of supplementation of Moringa oleifera aqueous extract(MOAE)at varying concentrations(0,100,200,and 400 mg/kg diet for 90 days)on growth performance,hematological,and some biochemical parameters of Nile ***,histological changes and immunohistochemical expression of caspase 3 in gills and livers were *** enhancements(Pells,hemoglobin,packed cell volume,white blood cells,and total serum protein were observed in fish fed 200 mg MOAE/kg diet compared with other ***,a significant reduction(Py function tests and non-significant changes in lipid profile were *** the other hand,fish fed 400 mg MOAE/kg diet revealed disturbance in the corresponding *** histological degenerative changes were detected in the gills and liver of fish fed 400 mg MOAE/kg *** comparison,fish fed 200 mg MOAE/kg diet showed the best histo-architectures of these organs compared with other *** immune expressions of caspase 3 were determined where gills and liver of fish fed 400 mg MOAE/kg diet revealed extensive number of positive caspase 3 cells indicating severe apoptotic ***,a dietary MOAE at 200 mg/kg diet is recommended to improve the growth performance,hematological parameters,liver and kidney functions in Nile ***,caution must be considered when using MOAE at a concentration over 200 mg/kg diet.

关键词： Growth performance Liver Gills Moringa oleifera Nile tilapia

Financial and non-financial determinants of the indebtedness of hospitals:the case of Poland

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Journal of Management Analytics 2024年第1期11卷 26-44页

作者： Katarzyna Miszczyńska elżbieta Antczak Department of Banking Faculty of Economics and SociologyUniversity of LodzLodzPoland Department of Spatial Econometrics Faculty of Economics and SociologyUniversity of LodzLodzPoland

The performance of Polish healthcare is still far from satisfactory,which is connected with growing indebtedness that adversely affects not only the development of healthcare but also the quality of medical services *** turn,the financial situation of hospitals depends on various indicators and the relationship between *** paper investigates the determinants of healthcare sector functioning in the context of hospitals’financial situation(dependent variable measured by total debt ratio).321 individual public units were examined between years 2007–*** specifically,the fixed effects panel data model in question measures and evaluates the impact of economic,regional,institutional,and social factors in determining the dependent *** study confirmed dependencies between financial and non-financial ratios along with their impact on the financial condition of studied *** management implications of our study lay the groundwork for the improvement of efficient resource management for public hospitals.

关键词： polish healthcare system hospitals’financial situation debt ratio panel data analysis

Smart prediction of liquefaction-induced lateral spreading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2310-2325页

作者： Muhammad Nouman Amjad Raja Tarek Abdoun Waleed el-Sekelly New york University(NyU)Abu Dhabi Abu Dhabi129188United Arab Emirates University of Management and Technology Lahore54372Pakistan Department of Civil and Environmental Eng. Rensselaer Polytechnic Institute(RPI)1108th StreetJEC 4049TroyNY12180USA Department of Structural Engineering Mansoura UniversityMansoura35516Egypt

The prediction of liquefaction-induced lateral spreading/displacement(Dh)is a challenging task for civil/geotechnical *** this study,a new approach is proposed to predict Dh using gene expression programming(GEP).Based on statistical reasoning,individual models were developed for two topographies:free-face and gently sloping *** with a comparison with conventional approaches for predicting the Dh,four additional regression-based soft computing models,*** process regression(GPR),relevance vector machine(RVM),sequential minimal optimization regression(SMOR),and M5-tree,were developed and compared with the GEP *** results indicate that the GEP models predict Dh with less bias,as evidenced by the root mean square error(RMSE)and mean absolute error(MAE)for training(i.e.1.092 and 0.815;and 0.643 and 0.526)and for testing(i.e.0.89 and 0.705;and 0.773 and 0.573)in free-face and gently sloping ground topographies,*** overall performance for the free-face topology was ranked as follows:GEP>RVM>M5-tree>GPR>SMOR,with a total score of 40,32,24,15,and 10,*** the gently sloping condition,the performance was ranked as follows:GEP>RVM>GPR>M5-tree>SMOR with a total score of 40,32,21,19,and 8,***,the results of the sensitivity analysis showed that for both free-face and gently sloping ground,the liquefiable layer thickness(T_(15))was the major parameter with percentage deterioration(%D)value of 99.15 and 90.72,respectively.

关键词： Lateral spreading Intelligent modeling Gene expression programming(GEP) Closed-form solution Feature importance