检索结果-南通市图书馆

Towards a New Strategic Understanding Between Egypt and PRC in the Twenty -First Century

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

外交评论（外交学院学报） 2000年第S1期20卷 35-43页

作者： Mohmmad El-sayed Selim CenterforAsianStudies FacultyofEconomics&PoliticalScienceCairoUniversit

Advances in high carbon dioxide separation performance of poly(ethylene oxide)-based membranes

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2020年第7期29卷 30-52,I0002页

作者： Samaneh Bandehali Abdolreza Moghadassi Fahime Parvizian sayed Mohsen Hosseini Takeshi Matsuura Ezatollah Joudaki Department of Chemical Engineering Faculty of EngineeringArak UniversityArak 38156-8-8349Iran Department of Chemical and Biological Engineering University of OttawaOttawaOntario K1N 6N5Canada

Poly(ethylene-oxide)(PEO)-based membranes have attracted much attention recently for CO2 separation because CO2 is highly soluble into PEO and shows high selectivity over other gases such as CH4 and ***,those membranes are not strong enough mechanically and highly crystalline,which hinders their broader applications for separation *** this review discussions are made,as much in detail as possible,on the strategies to improve gas separation performance of PEO-based *** of techniques such as synthesis of graft copolymers that contain PEO,cross-linking of polymers and blending with long chains polymers contributed significantly to improvement of *** of ionic liquids/nanoparticles has also been found ***,surface modification of nanoparticles has been done chemically or physically to enhance their compatibility with polymer *** a result of all such efforts,an excellent performance,i.e.,CO2 permeability up to 200 Barrer,CO2/N2 selectivity up to 200 and CO2/CH4 selectivity up to 70,could be *** method is to introduce functional groups into PEO-based polymers which boosted CO2 permeability up to 200 Barrer with CO2/CH4 selectivity between 40 and *** CO2 permeability of PEO-based membranes increases,without much change in selectivity,when the length of ethylene oxide is increased.

关键词： Membrane gas separation Molecular design Poly(ethylene oxide) CO2/CH4 separation

Role of hepatocyte nuclear factor 4-alpha in gastrointestinal and liver diseases

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2019年第30期25卷 4074-4091页

作者： Matthew M Yeh Dustin E Bosch sayed S Daoud Department of Pathology University of Washington School of MedicineSeattleWA 98195United States Department of Medicine University of Washington School of MedicineSeattleWA 98195United States Department of Pharmaceutical Sciences Washington State University Health SciencesSpokaneWA 99210United States

Hepatocyte nuclear factor 4-alpha(HNF4α)is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs(pancreas,stomach,and intestine).In liver,HNF4αis best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver *** of HNF4αexpression has been associated with many human diseases such as ulcerative colitis,colon cancer,maturity-onset diabetes of the young,liver cirrhosis,and hepatocellular ***,the precise role of HNF4αin the etiology of these human pathogenesis is not well *** information is known about the role of HNF4αisoforms in liver and gastrointestinal disease *** is,therefore,a critical need to know how disruption of the expression of these isoforms may impact on disease progression and *** this review,we will update our current understanding on the role of HNF4αin human liver and gastrointestinal *** further provide additional information on possible use of HNF4αas a target for potential therapeutic approaches.

关键词： Hepatocyte nuclear factor 4-alpha Liver cirrhosis Hepatocellular carcinoma Viral hepatitis Gastrointestinal tract Colorectal carcinoma Transcription factor

Morphology and magnetic traits of strontium nanohexaferrites:Effects of manganese/yttrium co-substitution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第7期37卷 732-740页

作者： M.A.Almessiere Y.Slimani H.S.El sayed A.Baykal Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 198231441 DammamSaudi Arabia Department of Nano-Medicine Research Institute for Research&Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 198231441 DammamSaudi Arabia Department of Biophysics Institute for Research&Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 198231441 DammamSaudi Arabia

Doped strontium(Sr) hexaferrites appeared potential candidates for microwave absorber *** by this idea, we examined the influence of manganese(Mn) and yttrium(Y) co-substitution on the microstructures,morphology and magnetic properties of Sr nanohexaferrites(Sr1-xMnxFe12-yYyO19,where 0.0 ≤ x = y ≤ 0.5) synthesized via citrate sol-gel auto-combustion technique. As-prepared samples were thoroughly characterized using diverse analytical tools. X-ray diffraction pattern reveals a single Mhexagonal crystalline phase. FE-SEM, TEM, HR-TEM show a hexagonal platelet-like structure. The magnetic hysteresis loops(measured at room and low temperature) of the as-prepared nanohexaferrites exhibit ferromagnetic(FM) behavior. Magnetic parameters including the saturation magnetization,remanence, coercive and magneto-crystalline anisotropy field are found to decrease with the increase in Mn2+ and Y3+ contents. Zero-and normal-field cooled magnetization measurements in the range of 2-400 K display the complete absence of blocking temperature, confirming the characteristic ferromagnetic behavior of the proposed composition.

关键词： Strontium hexaferrite Sol-gel auto-combustion Microstructure Morphology Magnetic properties Rare earths

Acid and non-acid reflux in patients refractory to proton pump inhibitor therapy:Is gastroparesis a factor?

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2013年第37期19卷 6193-6198页

作者： Anna Tavakkoli Bisma A sayed Nicholas J Talley Baharak Moshiree Department of Medicine Columbia University Medical Center Department of Sociology University of Miami Faculty of Health University of Newcastle Department of Gastroenterology University of Miami

AIM:To determine whether an increased number and duration of non-acid reflux events as measured using the multichannel intraluminal impedance pH(MII-pH)is linked to gastroparesis(GP).METHODS:A case control study was conducted in which 42 patients undergoing clinical evaluation for continued symptoms of gastroesophageal reflux disease(both typical and atypical symptoms)despite acid suppression ***-pH technology was used over 24 h to detect reflux episodes and record patients’*** evaluated in patients with documented GP and controls without GP by scintigraphy included total,upright,and supine number of acid and non-acid reflux episodes(pH4,respectively),the duration of acid and non-acid reflux in a 24-h period,and the number of reflux episodes lasting longer than 5 ***:No statistical difference was seen between the patients with GP and controls with respect to the total number or duration of acid reflux events,total number and duration of non-acid reflux events or the duration of longest reflux *** number of nonacid reflux episodes with a pH>7 was higher in subjects with GP than in *** addition,acid reflux episodes were more prolonged(lasting longer than 5min)in the GP patients than in controls;however,these values did not reach statistical ***-five patients had recorded symptoms during the 24 h study and of the 35 subjects,only 9%(n=3)had a positive symptom association probability(SAP)for acid/non-acid reflux and 91%had a negative ***:The evaluation of patients with a documented history of GP did not show an association between GP and more frequent episodes of non-acid reflux based on MII-pH testing.

关键词： Gastroparesis Non-acid gastroesophageal reflux Acid gastroesophageal reflux Multi-channel intraluminal impedance Functional bowel disorder

Influence of rare earth ion substitutions on the structural,optical,transport,dielectric,and magnetic properties of superparamagnetic iron oxide nanoparticles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2018年第3期7卷 218-228页

作者： R.M.KERSHI F.M.ALI M.A.sayed Physics Department Faculty of ScienceKing Khalid University Physics Department Faculty of ScienceIbb University Physics Department Faculty of ScienceSuez Canal University Physics Department Faculty of ScienceAl-Azhar University

Superparamgnetic Fe_3O_4 and RE:Fe_3O_4(RE=Dy,Nd,La)nanoparticles with an average crystallite size in the range of 15–24 nm,were synthesized by co-precipitation *** samples were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),vibrating sample magnetometer(VSM),UV–Vis spectroscopy,LCR bridge,and two-probe technique.X-ray diffraction patterns of all the investigated samples reveal the typical phase of magnetite structure,with a small contribution of orthoferrite(NdFeO_3)as a secondary phase in Nd:Fe_3O_4 *** saturation magnetization(M_s)of the samples has values in the range from 41.8 to 52.3 emu/g,and decreases with RE ion doping depending on the ionic *** values of the coercivity H_c and remanenceM_r,indicate the superparamagnetic nature of the investigated *** calculated values of indirect optical band gap of Fe_3O_4 and RE:Fe_3O_4 nanoparticles are in the range of0.9–1.25 *** dielectric constant of the samples decreases,while their activation energy increases with the increasing of ionic radii of dopants.

关键词： superparamgnetic iron oxide nanoparticles (SPIONs) rare earth (RE) ions structure,optical and activation energies electrical conductivity dielectric constant saturationmagnetization

Microstructure and mechanical properties of hot extruded 6016 aluminum alloy/graphite composites

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2018年第9期34卷 1580-1591页

作者： Mohamed M.El-sayed Seleman Mohamed M.Z.Ahmed Sabbah Ataya Department of Metallurgical and Materials Engineering Faculty of Petroleum and Mining Engineering Suez University 43518 Suez Egypt Suez and Sinai Metallurgical and Materials Research Center of Scientific Excellence (SSMMR-CSE) 43518 Suez Egypt The British University in Egypt Mechanical Engineering Deportment El-Sherouk City 11837 Cairo Egypt Department of Mechanical Engineering College of Engineering AI Imam Mohammad Ibn Saud Islamic University Riyadh 11432 saudi Arabia

The incorporation of graphite particles into AA6016 aluminum alloy matrix to fabricate metal/ceramic composites is still a great challenge and various parameters should be considered. In this study, dense AA6016 aluminum alloy/（0-20 wt%） graphite composites have successfully been fabricated by powder metallurgy process. At first, the mixed aluminum and graphite powders were cold compacted at 200 MPa and then sintered at 500 ℃ for 1 h followed by hot extrusion at 450 ℃. The influence of ceramic phases（free graphite and in-situ formed carbides） on microstructure, physical and mechanical properties of the produced composites were finally investigated. The results show that the fabricated composites have a relative density of over 98%. SEM observations indicate that the graphite has a good dispersion in the alloy matrix even at high graphite content. Hardness of all the produced composites was higher than that of aluminum alloy matrix. No cracks were observed at strain less than 23% for all hot extruded *** strength, reduction in height, ultimate tensile stress, fracture stress, yield stress, and fracture strain of all Al/graphite composites were determined by high precision second order equations. Both compressive and ultimate tensile strengths have been correlated to microstructure constituents with focusing on the in-situ formed ceramic phases, silicon carbide（SiC） and aluminum carbide（Al4 C3）. The ductile fracture mode of the produced composites became less dominant with increasing free graphite content and in-situ formed carbides. Wear resistance of Al/graphite composites was increased with increasing graphite content. Aluminum/20 wt% graphite composite exhibited superior wear resistance over that of AA6016 aluminum alloy.

关键词： AA6016/graphite composites Hot extrusion In-situ carbides Mechanical properties Wear resistance Fracture behavior

Molecular study of astrovirus, adenovirus and norovirus in community acquired diarrhea in children: One Egyptian center study

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2017年第11期7卷 987-990页

作者： Maysaa El sayed Zaki Nermen Abo El Kheir Clinical Pathology Department Mansoura Faculty of MedicineMansoura UniversityEgypta

Objective: To determine the prevalence of astrovirus, norovirus, adenovirus in children below five years old with diarrhea by multiplex reverse transcriptase polymerase chain reaction(RT-PCR) along with rotavirus antigen detection by enzyme linked immunosorbant ***: The study was conducted on children below five years old complaining of acute diarrhea. The study included stool examination by molecular method for detection of norovirus, adenovirus and astrovirus by multiplex RT-PCR. Rotavirus antigen was detected in the stool by enzyme linked immunosorbant ***: The study included 100 children below 5 years old with acute *** RT-PCR was positive in 34% of the children. The most frequently detected virus was rotavirus(44%), followed by norovirus(30%), adenovirus(20%) and astrovirus(14%). The clinical symptoms were more significantly associated with viral diarrhea such as fever(P = 0.03), bloody diarrhea(P = 0.025), vomiting(P = 0.000 1) and watery diarrheas(P = 0.05). The frequency of diarrhea with viral pathogen was significantly presented in winter season(39.7%). There were significant frequencies of norovirus and adenovirus in age ranging 1–2 years old(P = 0.04, P = 0.01 respectively).Conclusions: The present study spotlights on the prevalence of viral pathogens as an important etiology in diarrhea in children below five years old. Astrovirus, norovirus and adenovirus are common along with rotavirus in this group of patients. Multiplex PCR leads to improve the laboratory diagnosis of these viruses along with antigen detection method. Further longitudinal studies are required to evaluate the epidemiological data associated with these viruses and for proper management of such drastic infection.

关键词： Diarrhea Astrovirus Adenovirus Norovirus Multiplex-RT PCR

Secret Key Optimization for Secure Speech Communications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第8期72卷 3025-3037页

作者： Osama S.Faragallah Mahmoud Farouk Hala S.El-sayed Department of Information Technology College of Computers and Information TechnologyTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Department of Computer Science and Engineering Faculty of Electronic EngineeringMenoufia UniversityMenouf 32952Egypt Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Kom 32511Egypt

This paper answers three essential questions for audio speech cryptosystems in time and discrete transform *** first question is,what are the best values of sub-keys that must be used to get the best quality and security for the audio cryptosystem in time and discrete transform *** second question is the relation between the number of sub-keys,the number of secret keys used,and the audio speech signal block’s ***,how many possible secret keys can be used to get the best quality and security results for the audio speech cryptosystem in time and discrete transform *** audio cryptosystem discussed before in recent research is applied to answer the three previous *** simulation results and analysis answer all three questions;first,there is no specific,well-defined format or rule for sub-key values that must be used to get a better *** the second question,yes,there is a direct relationship between the number of applicable keys,number of available sub-keys,and block size of speech audio signal and formulated into a first-order *** the third question,each discrete transform domain has a specific acceptable range of sub-keys that imply a particular number of keys that can be used to get a better cryptosystem.

关键词： Audio cryptosystem chaotic baker map secret key size