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International Journal of Ophthalmology(English edition) 2020年第6期13卷 907-912页

作者： mahmoud abdel-Radi Zeiad Eldaly Hazem abdelmotaal Reham abdelrahman Mohamed Sayed Kamel Soliman Department of Ophthalmology Assiut UniversityAssiut 71516Egypt

AIM:To compare corneal demarcation line(DL)depth in both accelerated epithelium-off and trans-epithelium cross linking(CXL)using anterior segment optical coherence tomography(AS-OCT)and its relation to maximum keratometry(Kmax)progression in both ***:A prospective comparative interventional study where patients with mild to moderate keratoconus(KC)were classified into two groups:accelerated epitheliumoff and trans-epithelium CXL based on corneal *** of corneal DL depth was carried out after 3mo by *** readings were evaluated after one year follow up using the Scheimpflug imaging ***:Study included 74 eyes of 44 *** A underwent epithelium-off CXL(41 eyes),while Group B underwent trans-epithelium CXL(33 eyes).At 3mo follow up,mean corneal DL depth in Group A was 219.9±58.4μm while in Group B was 127.2±7.8μm(P0.05).In addition,no significant change in corneal pachymetry was found in both groups(meanchange at 1y:6.4±4.7 and-10.1±2.3μm in Groups A and B respectively).CONCLUSION:Despite a significantly deeper corneal DL depth created by accelerated epithelium-off CXL technique compared to accelerated trans-epithelium CXL,there is no significant impact on keratoconus progression.

关键词： anterior segment optical coherence tomography cross linking demarcation line keratoconus

ANALYTICAL MODELS BASED DISCRETE-TIME QUEUEING FOR THE CONGESTED NETWORK

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International Journal of Modeling, Simulation, and Scientific Computing 2012年第1期3卷 68-89页

作者： MOFLEH AL-DIABAT HUSSEIN abdel-JABER FADI THABTAH OSMAN ABOU-RABIA mahmoud KISHTA Computer Science Department Al-al-Bayt University Jordan Department of Computer Science The World Islamic Sciences&Education(W.I.S.E.)University Amman Jordan Management Information System Department Philadelphia University AmmanJordan Department of Mathematics and Computer Science Laurentian University Sudbury ONCanada Dean of Academic Research Philadelphia University AmmanJordan

Congestion is one of the well-studied problems in computer networks,which occurs when the request for network resources exceeds the buffer *** active queue management techniques such as BLUE and RED have been proposed in the literature to control congestions in early *** this paper,we propose two discrete-time queueing network analytical models to drop the arrival packets in preliminary stages when the network becomes *** first model is based on Lambda Decreasing and it drops packets from a probability value to another higher value according to the buffer *** the second proposed model drops packets linearly based on the current queue *** compare the performance of both our models with the original BLUE in order to decide which of these methods offers better quality of *** comparison is done in terms of packet dropping probability,average queue length,throughput ratio,average queueing delay,and packet loss rate.

关键词： Analytical models congestion control discrete-time queueing simulation

Virtual Difference Voltage Scheme for Fault Detection in VSC-HVDC Transmission Systems

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Journal of Modern Power Systems and Clean Energy 2020年第5期8卷 991-1004页

作者： mahmoud M.Elgamasy abdel-Maksoud I.Taalab Tamer A.Kawady Mohamed A.Izzularab Nagy I.Elkalashy Electrical Engineering Department Faculty of EngineeringMenoufia University32511 Shebin ElkomEgypt

In this paper,a fast fault detection scheme for voltage source converter based high-voltage direct current(VSCHVDC)transmission systems is *** on Bergeron model equations,the remote terminal voltage of an adopted transmission system is calculated in terms of the local measured current and voltage ***,the computed voltage of the remote terminal is compared with the corresponding actual measured-communicated *** that the considered transmission system is functioning well,the difference between the computed and measured voltages is almost ***,a considerable virtual voltage arises for fault *** the voltage difference exceeds a predetermined threshold,a fault condition can be *** a reliable communication link is required,the delay for detecting the fault is not caused by the communication *** evaluation purpose,a detailed simulation is developed using PSCAD/EMTDC with various fault locations,including the cases near the inside or outside of the protected transmission *** results corroborate a fast detection scheme depending on a moderate sampling/processing frequency level.A high security level is verified even with the worst external faults,or with the misaligned measured samples at the *** corroborates the suitability of the proposed scheme for protecting multi-terminal HVDC systems.

关键词： Fault detection high-voltage direct current(HVDC) voltage source converter(VSC) transmission system

Comparison between Two Different Manufactured Forms of β-Tricalcium Phosphate Bone Graft in Immediate Implant Placement

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Open Journal of Stomatology 2024年第11期14卷 410-420页

作者： Abdulaleem mahmoud Sharroud abdel aziz Baiomy Abdullah Mohamed Alaa El-Din Mohamed Department of Oral and Maxillofacial Surgery Faculty of Dental Medicine Al-Azhar University Assuit Egypt

Objectives: The aim of this study was to compare the efficacy of using the synthetic β-TCP bone grafting material in two different manufacturing forms (putty and granular) in grafting the jumping zone around immediate implant. Patients and Method: A randomized controlled clinical and radiographic trial was conducted on 24 male patients aged from 45 - 55 with badly decayed non-restorable teeth in the posterior mandibular area and seeking for receiving immediate dental implant directly after extraction. Vertical bone height and bone density were taken at time of implant placement and 6 months postoperatively. Results: The Putty form group and the Granular form group did not differ statistically in terms of age, post-operative complications, or implant outcome six months postoperatively. Additionally, there was a statistically significant increase in Putty form group compared to the Granular form group regarding Marginal bone loss 6 months postoperatively, but there was no statistically significant difference between the Putty form group and the Granular form group regarding Bone density by CBCT. Conclusion: The β-TCP Putty material, compared to β-TCP granular, displayed better surgical handling properties, and both forms had no adverse effect on bone formation, bone tissue maturation or graft volume stability, The β-TCP granular material, compared to β-TCP putty, displayed less marginal bone loss 6 months post-operatively.

关键词： β-Tricalcium Phosphate Bone Substitute Putty Form and Granular Form Grafting the Jumping Zone around Immediate Implant

Investigation of soliton solutions with different wave structures to the(2+1)-dimensional Heisenberg ferromagnetic spin chain equation

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Communications in Theoretical Physics 2020年第3期72卷 7-13页

作者： M S Osman K U Tariq Ahmet Bekir A Elmoasry Nasser S Elazab M Younis mahmoud abdel-Aty Department of Mathematics Faculty of ScienceCairo UniversityGizaEgypt Department of Mathematics Faculty of Applied ScienceUmm Alqura UniversityMakkah 21955Saudi Arabia School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Department of Mathematics Mirpur University of Science and TechnologyMirpur(AJK)10250Pakistan Neighbourhood of Akcaglan Imarli StreetNumber:28/426030EskisehirTurkey Mathematics department College of ScienceMajmaah UniversitySaudi Arabia Punjab University College of Information Technology University of the PunjabLahore 54590Pakistan Department of Mathematics Faculty of ScienceSohag UniversitySohagEgypt Applied Science University Bahrain

The principal objective of this article is to construct new and further exact soliton solutions of the(2+1)-dimensional Heisenberg ferromagnetic spin chain equation which investigates the nonlinear dynamics of magnets and explains their ordering in ferromagnetic *** solutions are exerted via the new extended FAN sub-equation *** successfully obtain dark,bright,combined bright-dark,combined dark-singular,periodic,periodic singular,and elliptic wave solutions to this equation which are interesting classes of nonlinear excitation presenting spin dynamics in classical and semi-classical continuum Heisenberg systems.3D figures are illustrated under an appropriate selection of *** applied technique is suitable to be used in gaining the exact solutions of most nonlinear partial/fractional differential equations which appear in complex phenomena.

关键词： soliton solutions Heisenberg ferromagnetic equation FAN sub-equation method

Effect of nursing intervention on improving awareness of high-risk patients about stroke prevention

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Frontiers of Nursing 2025年第1期12卷 133-144页

作者： Mona M.Abd El-Maksoud Aida S.Alqarni Dawlat Ahmed mahmoud Gharib Fatma Mohammed Ahmed Eman Elsayed Hussein Community Health Nursing Department Nursing CollegeKing Khalid UniversityAbha 62217Saudi Arabia Community Health and Mental and Psychiatric Health Nursing Department Faculty of NursingHelwan UniversityCairo 11571Egypt Community Health Nursing Department Medical Surgical Nursing DepartmentNursing CollegeKing Khalid UniversityAbha 62217Saudi Arabia Community Health Nursing Department Faculty NursingZagazig UniversityZagazig 44511Egypt Medical Surgical Nursing Department Faculty of NursingZagazig UniversityZagazig 44511Egypt

Objective: Stroke is perceived as a serious illness although it is preventable, and lifestyle alterations can be made to reduce its risk. Improvement of stroke care should be achieved through awareness of public, especially through high-risk group. Henceforth, the aim of this study was to evaluate the effect of nursing intervention on improving awareness of high-risk people about stroke prevention. Methods: A quasi-experimental design was used to carry out this study, where a purposive sample of 80 adult patients at high risk for stroke were enrolled while they were attending the out-patient clinics of Zagazig University Hospitals for follow-up treatment;they were divided into two groups: case (40 patients) and control (40 patients). An interview questionnaire was used to assess patients’ knowledge regarding warning signs, risk factors, and immediate treatment;attitude;and their practice for prevention for stroke at pretest and posttest. Results: The study revealed the poor level of knowledge, bad level of preventive behavior, and negative attitude regarding stroke prevention at pre-intervention. However, after intervention, the high-risk people had fair level of knowledge with moderate practice for stroke prevention and positive attitude, with statistically significant difference between pre-post intervention and between the case and control groups. Conclusions: The study revealed that the nursing intervention seemed to change the knowledge, practice, and attitude of subjects regarding stroke prevention. This, in turn, implies that awareness of prevention of stroke and high-risk factor control could be important to reduce the burden of stroke in Egypt. Thus, further research on a larger scale is required to improve population knowledge and behavior for stroke prevention and control.

关键词： awareness high-risk group intervention nursing prevention stroke

Elevated Temperatures Tensile Characteristics of Cast A356/Al<sub>2</sub>O<sub>3</sub>Nanocomposites Fabricated Using a Combination of Rheocasting and Squeeze Casting Techniques

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Materials Sciences and Applications 2011年第5期2卷 390-398页

作者： El-Sayed Youssef El-Kady Tamer Samir mahmoud Mohamed abdel-aziz Sayed Mechanical Engineering Department Faculty of Engineering King Khalid University (KKU) Abha Kingdom of Saudi Arabia.

In the present investigation, the tensile properties of A356/Al2O3 nanocomposites at both ambient and elevated temperatures were studied. The A356/Al2O3 nanocomposites were fabricated using a combination between the rheocasting and squeeze casting techniques. The A356 matrix alloy was reinforced with Al2O3 nanoparticulates having average sizes of 60 nm and 200 nm with different volume fractions up to 5 vol%. The results revealed that the A356/Al2O3 nanocomposites exhibited better mechanical properties than the A356 monolithic alloy. Such improvement in the mechanical properties was observed at both room and elevated temperatures up to 300°C. Increasing the volume fraction and/or reducing the size of Al2O3 nanoparticulates increase both the tensile and yield strengths of the nanocomposites.

关键词： Nanocomposites Mechanical Properties Rhecocasting Squeeze Casting Aluminum Alloys

Endoscopic Third Ventriculostomy versus Ventriculo-Peritoneal Shunt for Infant Hydrocephalus

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Open Journal of Modern Neurosurgery 2020年第2期10卷 193-202页

作者： Khaled Ismail abdel-aziz Radwan Nouby mahmoud Ahmed Thabet Mohammad Fekry Elshirbiny Department of Neurosurgery Faculty of Medicine Aswan University Aswan Egypt Department of Neurosurgery Faculty of Medicine Assiut University Assiut Egypt

Introduction: Patients with hydrocephalus, which is the most pediatric neurological disorder, undergo Cerebrospinal fluid (CSF) diversion through third ventriculostomy or ventriculo-peritoneal shunt. Up to date, the optimal hydrocephalus treatment modality is not clear. Aim: We compared the outcome of endoscopic third ventriculostomy (ETV) versus ventriculo-peritoneal shunt (VP shunt) as a second surgical intervention in management of Infant hydrocephalus concerning success rate and complications. Patients and Methods: We conducted an observational study of 52 children with hydrocephalus (congenital or acquired) in whom CSF diversion was performed using either ETV or VP shunt in randomized control trial. Results: During the period examined, 52 children, 26 underwent ETV and 26 underwent VP shunt. The mean age was 11.0 ± 4.3 months in ETV and 11.3 ± 4.7 months in VP shunt. Postoperative infection in the ETV group was lower than in the VP shunt group (23.1% vs. 53.8% P = 0.045). Regarding operating time, In ETV group operation duration was 46.9 min and 64.3 min in the V-P shunt group (P = 0.13). There was no statistically significant difference between the two study groups regarding the rate of obstruction, change in occipital frontal circumference (OFC) or the need of revision surgery. One year survival for VP shunt group vs. ETV group was 46.2% vs. 65.4% respectively. Conclusion: ETV associated with lower rates of postoperative infection and shorter operation time with no significant difference in rates of obstruction, change in OFC and revision surgery in comparison to VP shunt.

关键词： ETV VPS Pediatric Hydrocephalus

Clinicopathological features and surgical outcome of patients with fibrolamellar hepatocellular carcinoma(experience with 22 patients over a 15-year period)

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World Journal of Gastrointestinal Surgery 2017年第2期9卷 61-67页

作者： Mohamed abdel Wahab Ehab El Hanafy Ayman El Nakeeb mahmoud abdelwahab Ali Gastroenterology Surgical Center Mansoura UniversityMansoura 35516Egypt

AIM To evaluate the clinicopathological features and the surgical outcomes of patients with fibrolamellar hepato-cellular carcinoma(FL-HCC)over a 15-year period. METHODS This is a retrospective study including 22 patients with a pathologic diagnosis of FL-HCC who underwent hepatectomy over a 15-year period. Tumor characteristics,survival and recurrence were evaluated. RESULTS There were 11 male and 11 female with a median age of 29 years(range from 21 to 58 years). Two(9%)patients had hepatitis C viral infection and only 2(9%)patients had alpha-fetoprotein level > 200 ng/m L. The median size of the tumors was 12 cm(range from 5-20 cm). Vascular invasion was detected in 5(23%)patients. Four(18%)patients had lymph node metastases. The median follow up period was 42 mo and the 5-year survival was 65%. Five(23%)patients had a recurrent disease,4 of them had a second surgery with 36 mo median time interval. Vascular invasion is the only significant negative prognostic factor CONCLUSION FL-HCC has a favorable prognosis than common HCC and should be suspected in young patients with non cirrhotic liver. Aggressive surgical resection should be done for all patients. Repeated hepatectomy should be considered for these patients as it has a relatively indolent course.

关键词： Fibrolamellar hepatocellular carcinoma Common hepatocellular carcinoma Recurrence after resection fibrolamellar hepatocellular carcinoma Pathology of fibrolamellar hepatocellular carcinoma Survivalefter resection fibrolamellar hepatocellular carcinoma

Effect of Pd or Ir on the catalytic performance of Mo/H-ZSM-5 during the non-oxidative conversion of natural gas to petrochemicals

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Journal of Natural Gas Chemistry 2008年第4期17卷 337-343页

作者： Ahmed K.Aboul-Gheit Ahmed E.Awadallah Salah M.El-Kossy abdel-Lateef H.mahmoud Process Development Division Egyptian Petroleum Research Institute Faculty of Science Department of ChemistryMNF University Ageeba Petroleum Co.

Natural gas conversion to petrochemicals, principally, benzene, naphthalene, toluene, as well as ethylene under non-oxidative conditions was examined in a fixed bed flow reactor at 700 ℃ and gaseous hourly space velocity （GHSV） of 1500 ml·g ^-1·h^-1 at time-on-stream ranging from 5 rain to 4 h using catalysts containing 6.0%Mo/H-ZSM-5 promoted with Pd or Ir metal. The catalysts were characterized by XRD, TPD, and TGA. The addition of Pd or Ir to 6%Mo/H-ZSM-5 catalyst promoted ethylene production but inhibited the cyclization reaction to aromatics owing to the strong interaction between these noble metals and the framework Al species, which were attached to the acid sites during the impregnation process. Coke deposition on the catalysts was found to decrease upon addition of 0.5wt% of Pd or Ir to 6%Mo/H-ZSM-5 catalyst owing to the hydrogenating activity of these metals.

关键词： natural gas methane benzene ethylene molybdenum Pd Ir H-ZSM-5