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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.

Assessment of hepatic fibrosis in pediatric cases with hepatitis C virus in Egypt

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World Journal of Gastroenterology 2007年第20期13卷 2846-2851页

作者： Manal A el-Hawary Mona s el-Raziky gamal Esmat Hanan soliman Amr Abouzied Maissa el-Raziky Wafaa el-Akel Rokaya el-sayed Fatma shebl abdel aziz shaheen Hanaa el-Karaksy Department of Pediatrics Fayoum UniversityEgypt Department of Pediatrics Cairo UniversityEgypt Department of Tropical Medicine Cairo UniversityEgypt Department of Pathology Cairo UniversityEgypt Department of Tropical Medicine Hepatitis C ProjectEgypt Department of Public Health National Liver InstituteEgypt

AIM: To assess hepatic fibrosis and factors associated with its progression in children with HCV infection. METHODs: At the Hepatology Unit,Cairo University Children's Hospital,a single liver biopsy was performed to 43 children with HCV infection after an informed consent between 1998-2004. Their mean age at liver biopsy was 8.67 ± 4.3 years. REsULTs: Among the 43 patients' biopsies,12 (27.9%) were having no fibrosis,20 (46.5%) mild fibrosis and 11 (25.6%) moderate to severe fibrosis. The median time for development of fibrosis was estimated to be 5.5 years. Developing fibrosis was significantly associated with shorter duration from first detected ALT elevation to biopsy (12 mo vs 1.2 mo,P = 0.015) and having higher levels of direct serum bilirubin (0.3 mg/dL vs 0.5 mg/dL,P = 0.048). No association was found between fibrosis stage and the presence of co-morbid conditions (P = 0.33). CONCLUsION: Hepatic fibrosis was present in 72.1% of children with HCV infection. The development of fibrosis was associated with higher levels of direct serum bilirubin. There was no significant association between fibrosis and age,duration of infection,risk factors,co-morbid conditions and most biochemical parameters.

关键词： Children Egypt Fibrosis Hepatitis C virus Liver

Fabrication, Microstructure, Thermal and electrical Properties of Copper Heat sink Composites

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Materials sciences and Applications 2016年第9期7卷 542-561页

作者： Walid Daoush Ahmed swidan gamal abd el-aziz Mohamed abdelhalim Department of Production Technology Faculty of Industrial Education Helwan University Cairo Egypt Present Address: Department of Chemistry Faculty of Science Al-Imam Muhammad Ibn Saud Islamic University Al Riyadh KSA Mechanical Department Ameeria Integrated Technical Cluster Cairo Egypt Mechanical Department Faculty of Industrial Education Suez University Suez Egypt

Copper as well as copper base composites reinforced with coated and uncoated 1 wt% diamond, graphite particles or short carbon fibers are prepared by powder metallurgy process. The reinforcement particles were encapsulated with silver as well as copper layer by using the electroless deposition technique to investigate the influence of the reinforcement surface coating on the microstructure, density, electrical and thermal properties of the sintered samples. The coated and the uncoated powders were cold compacted at 600 MPa, and then sintered at 1173 K (900°C) for 2 h under hydrogen atmosphere. The phase composition, morphology and microstructure of the prepared powders as well as the copper base sintered composites were investigated using X-ray diffraction analysis (XRD) and scanning electron Microscope (sEM) equipped with an Energy Dispersive spectrometer (EDs) respectively. The density of the sintered composites was measured by Archimedes method. The copper base consolidated composites had a density up to 96% and the reinforcement coated particles were distributed uniformly within the copper matrix better than the uncoated one. The electrical resistivity at room temperature and the heat transfer conduction of the produced samples were measured in a temperature range between 323 K (50°C) and 393 K (120°C). The results observed that the sintered materials prepared from the coated powder have lower electrical resistivity than the sintered materials prepared from the mixed powders. On the other hand the thermal conductivity values were calculated using the heat transfer conduction values by means of the Fourier formula. The results observed that the thermal conductivity of copper is (391 W/m·K), 1 wt% diamond/Cu is (408 W/m·K), 1 wt% graphite coated silver/Cu is (393 W/m·K), 1 wt% Cu coated short carbon fiber/Cu is (393 W/m·K), graphite/Cu is (383 W/m·K) and short carbon fiber/Cu is (382 W/m·K). The obtained compos

关键词： Heat sink Powder Metallurgy Matrix Composites electrical Resistivity Thermal Conductivity Natural Forced Convection

Tagetones A and B, new cytotoxic monocyclic diterpenoids from flowers of Tagetes minuta

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Chinese Journal of Natural Medicines 2017年第7期15卷 546-549页

作者： sabrin Ragab Mohamed Ibrahim gamal abd Allah Mohamed Department of Pharmacognosy and Pharmaceutical Chemistry College of Pharmacy Taibah University Al-Madinah Al-Munawarah 30078 Saudi Arabia Department of Natural Products and Alternative Medicine Faculty of Pharmacy King Abdulaziz University Jeddah 21589 Saudi Arabia

Tagetones A(1) and B(2), two new monocyclic diterpenoids were isolated from the n-hexane fraction of fresh flowers of Tagetes minuta L.(Asteraceae). Their structures were established by multiple spectroscopic methods(IR, HR-EsI-Ms, and 1D-, and 2D-NMR), in addition to comparison with literature data. Compound 1 showed cytotoxic activity towards MCF7 and A549 cancer cells with IC_(50) values being 4.68 and 4.24 μmol·L^(-1), respectively, compared to doxorubicin(IC_(50) 0.13 and 1.12 μmol·L^(-1), respectively). Compound 2 also exhibited significant activity against HCT116 cancer cells(IC_(50), 6.30 μmol·L^(-1)).

关键词： Tagetes minuta Asteraceae Monocyclic diterpenoids Tagetones Cytotoxic

Evaluation of Antioxidants, Total Phenolics and Antimicrobial Activities of Ethyl Acetate Extracts From Fungi Grown on Rice straw

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Journal of Renewable Materials 2019年第7期7卷 667-682页

作者： Bahaa T.shawky Mohammed Nagah Mosad A.Ghareeb gamal M.el-sherbiny saad A.M.Moghannem Mohamed s.abdel-aziz Microbial Chemistry Department National Research CentreDokki-12622CairoEgypt Medicinal Chemistry Department Theodor Bilharz Research InstituteKornaish El-NileWarrak El-HadarImbaba(P.O.30)Giza 12411Egypt Botany and Microbiology Department Faculty of ScienceAzhar UniversityNasr CityCairoEgypt

Rice straw(Rs)collected from Egyptian agricultural environment(Al-Masied village-Alsharqia Governorate-Egypt)was used as substrate for three fungal isolates namely:4b,1Asp,Pleurotus ostreatus NRRL 3501 and mixed culture of(4b,1Asp).Isolates number 4b and 1Asp were identified using the molecular technique(18s rRNA).Isolate 4b and 1Asp,were identified as Trichoderma saturnisporum MN1-EGY and Aspergillus niger MN2-EGY,*** saturnisporum MN1-EGY extract exhibited the highest antimicrobial activity compared to the other fungal *** phenolic,antimicrobial and antioxidant activities were also determined from the ethyl acetate extract of rice straw inoculated by these *** antioxidant scavenging concentration(sC50)values of the tested samples were 88.84,91.45,94.65 and 100.0μg/ml,respectively for Pleurotus sp.,Aspergiluus niger,Aspergiluus niger+Trichoderma sp.,and Trichoderma sp.,after 15 days incubation,compared to ascorbic acid as positive control with sC50 value equal to 8.0μg/*** phenolic contents(TPCs)were maximum in Pleurotus *** and found to be the most polyphenolic enriched sample(380.64 mg GAE/g dry extract)compared to extracts of Aspergiluusniger,Aspergiluus niger+Trichoderma sp.,and Trichoderma sp.(261.89,198.52,and 119.80 mg GAE/g dry extract),*** GC-Ms analysis has been also performed for the promising extracts.

关键词： Rice straw fungi molecular identification antimicrobial antioxidant total phenolics

A computer-based image analysis for tear ferning featuring

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Journal of Innovative Optical Health sciences 2015年第5期8卷 40-49页

作者： Ali s.saad gamal A.el-Hiti Ali M.Masmali Department of Biomedical Technology College of Applied Medical sciences King saud University P.O.Box 10219 Riyadh 11433Saudi Arabia Cornea Research Chair(CRC) Department of Optometry College of Applied Medical SciencesKing Saud University Riyadh 11433Saudi Arabia

The present work focuses on the development of a novel computer-based approach for tear ferning(TF)*** original TF images of the recently developedfive-point grading scale have been used to assign a grade for any TF image automatically.A vector characteristic(VC)representing each grade was built using the reference images.A weighted combination between features selected from textures analysis using gray level co-occurrence matrix(GLCM),power spectrum(Ps)analysis and linear specificity of the image were used to build the VC of each grade.A total of 14 features from texture analysis were *** at di®erent frequency points and number of line segments in each image were also *** features from GLCM have shown significant di®erences between the recently developed grading scale images which are:angular second moment at 0and 45,contrast,and correlation at 0and 45;thesefive features were all included in the characteristic *** specific power frequencies were used in the VC because of the discrimination *** of line segments was also chosen because of dissimilarities between images.A VC for each grade of TF reference images was constructed and was found to be significantly different from each other'*** is a basic and fundamental step toward an automatic grading for computer-based diagnosis for dry eye.

关键词： Objective grading tear ferning new grading scale texture analysis image processing Ps

New Polymer syntheses Part 60: A Facile synthetic Route to Polyamides Based on Thieno[2,3-b]thiophene and Their Corrosion Inhibition Behavior

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Chinese Journal of Polymer science 2018年第7期36卷 835-847页

作者： Kamal I.Aly Amr H.Moustafa Essam K.Ahmed Hany M.abd el-lateef Mohamed gamal Mohamed sahar M.Mohamed Polymer Research Lab Chemistry Department Faculty of Science Assiut University Chemistry Department Faculty of Science Sohag University Chemistry Department Faculty of Science Minia University Chemistry Department College of Science King Faisal university

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer la with different kinds of diacid chlorides （including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4＇-azodibenzoyl, 3,3＇-azodibenzoyl, p-phenylene diacryloyl） in the presence of LiC1 and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy （including 1 H-NMR and 13 C-NMR） and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis （TGA）, wide-angle X-ray diffraction analysis （WAXD） and scanning electron microscopy （sEM）. Also, the corrosion inhibition behavior of selected examples ofpolyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol＇L-1 HCI was studied using potentiodynamic polarization （PDP） and electrochemical impedance spectroscopy （EIs） methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency （P, %） was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.

关键词： Thieno[2 3-b]thiophene Polymer synthesis Thermal properties Industrial applications Corrosion inhibition

Role of relevant immune-modulators and cytokines in hepatocellular carcinoma and premalignant hepatic lesions

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World Journal of Gastroenterology 2018年第11期24卷 1228-1238页

作者： abdel-Rahman N Zekri somaya el Deeb Abeer A Bahnassy Abeer M Badr Mona s.abdellateif gamal Esmat Hosny salama Marwa Mohanad Ahmed Esam el-dien shimaa Rabah Assmaa abd elkader Molecular Virology and Immunology Unit Department of Cancer BiologyNational Cancer InstituteCairo University Department of Zoology Faculty of ScienceCairo University Department of Pathology National Cancer InstituteCairo University Medical Biochemistry and Molecular Biology Department of Cancer BiologyNational Cancer InstituteCairo University Department of Hepatology and Tropical Medicine Faculty of MedicineCairo University Department of Biochemistry Misr University for Science and Technology

AIM To assess the levels of different immune modulators in patients with hepatocellular carcinoma(HCC),in relation to other hepatic *** Eighty-eight patients were included in the current study and represented patients with HCC(20),liver cirrhosis(28) and chronic hepatitis(CH;25),and normal controls(NC;15).Peripheral blood was isolated for immunophenotyping of active myeloid dendritic cells(m DCs;CD1 c and CD40),mature inactive myeloid cells(CD1 c and HLA),active plasmacytoid cells(p DCs;CD303 and CD40),mature inactive p DCs(CD30 and HLA),active natural killer(NK) cells(CD56 and CD161),active NK cells(CD56 and CD314) and inactive NK cells(CD56 and CD158) was done by flow *** levels of interleukin(IL)-2,IL-10,IL-12,IL-1β,interferon(IFN)-α,IFN-γ and tumor necrosis factor(TNF)-αR2 were assessed by *** Active m DCs(CD1 C+/CD40+) and inactive m DCs(CD1 c+/HLA+) were significantly decreased in HCC patients in relation to NC(P ssion on active p DCs was decreased in HCC patients(P s level was not significantly changed among other *** p DCs(CD303+/HLA+),inactive NKs(CD56+/CD158+) and active NKs(CD56+/CD161+) were not statistically changed among the four groups studied;however,the latter was increased in CH(P s statistically decreased in HCC,CH and cirrhosis(P s not expressed in 63%(12/20) of HCC *** was significant decrease of IL-2,IFN-α and IFN-γ(P significant increase in IL-10,IL-1β,and TNF-αR2(P spectively) in HCC *** was inverted correlation between IL-12 and IL-1β in HCC(r =-0.565,P strong correlation between p DCs(CD303+/CD40+) and NKs(CD56+/CD161+;r = 0.512,P s well as inactive m DCs(CD1 c+/HLA+) and inactive NK cells(CD56+/CD158+;r = 0.945,P sION NKG2 D,CD40,IL-2 and IL-10 are important modulators in the development and progression of HCC.

关键词： Hepatocellular carcinoma Hepatitis C virus NKG2D CD40 interleukin-2 interleukin-10 myeloid dendritic cells plasmacytoid cells natural killer cell Cytokines

Effects of γ-irradiation and Deformation Temperature on Tensile Properties of Pb-2 mass% sb Alloy

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Journal of Iron and steel Research International 2016年第7期23卷 733-738页

作者： Gh MOHAMMED s.EI-gamal Physics Department Faculty of ScienceNorthern Borders University Physics Department Faculty of EducationAin Shams University

Effects ofγ-irradiation and deformation temperature（T）on the tensile properties of Pb-2mass% sb alloys were *** samples were annealed at 458 Kfor 2hin air,then water quenched after they wereγ-irradiated（the different doses were 0.5,1.0,1.5,and 2.0 MGy）.The tensile properties were performed using stress-strain measurements at a constant strain rate（1.2×10^（-3） s^（-1））and at different T（303-393K）.It was found that at constant dose,the fracture stress（σF）decreases while the fracture strain（εF）increases as *** particular T,σFincreases whileεFdecreases with increasing *** strain-hardening exponent（n）,which is the slope of the relation between ln（σ）and ln（ε）of the parabolic part of the stress-strain curve,was determined and its values increase as Tincreases and decrease as the dose *** value of the activation energy increases as the dose increases from 0.07 eV for un-irradiated sample to 0.1eV for the 2 MGy-irradiated *** values are in accordance with that needed for dislocation movement and ordering *** interpretation of the results was given,based on the creation of point and line defects due toγ-irradiation,and that results in a distribution of beta phase（sb-phase）,leading to a difficulty in the movement of dislocations,so there is an increase in alloy hardness.

关键词： γ-irradiation deformation temperature tensile property Pb-2 mass% sb alloy