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International Journal of Ophthalmology(English edition) 2020年第1期13卷 129-134页

作者： Amr Mounir Engy mohamed Mostafa Hatem Ammar osama Ali Mohammed Alahmady Hamad Alsmman Mahmoud mohamed Farouk mohamed Gamal Elghobaier Department of Ophthalmology Sohag Faculty of MedicineSohag UniversitySohag 82524Egypt Egyptian Police Hospitals Cairo 11765Egypt

AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high ***: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo ***: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.

关键词： transepithelial photorefractive keratectomy femtosecond laser assisted keratomileusis high myopia corneal haze Egypt

Unsteady Operation of New Type Turbofan Engine with Aerodynamic Torque Converter Reducing Front Fan Speed

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Journal of Thermal Science 2005年第3期14卷 206-210页

作者： Toshiaki KANEMOTO Seita SEKI Kazunori IDENO ahmed mohamed GALAL Kyushu Institute of Technology Sensui 1-1 Tobata Kitakyushu 804-8550 Japan ProfessorKyushu Institute of Technology Sensui 1-1 Tobata Kitakyushu 804-8550 JapanKyushu Institute of Technology Sensui 1-1 Tobata Kitakyushu 804-8550 JapanKyushu Institute of Technology Sensui 1-1 Tobata Kitakyushu 804-8550 Japan

It is desired to increase the rotational speed of the core engine of the turbofan so as to get the best efficiency for the next leap of engine technology. The conventional mechanism in which the front fan is directly connected to the output shaft of a core engine, have a limit of increasing the spool speed, because the fan diameter is very large. The authors have proposed a new driving system in which the front fan is driven through the aerodynamic torque converter. The front fan can work at the best performance at slower speed while the core engine runs more efficiently at higher speed. Continuously, this paper discusses the response of the front fan in the unsteady operation of the core engine, accompanying with the internal flow. The system has the acceptable responsibility in the unsteady operation which is very important for the aircrafts.

关键词： turbofan engine front fan torque converter rotational speed

Study of the degradation behavior and the biocompatibility of Mg-0.8Ca alloy for orthopedic implant applications

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Journal of Magnesium and Alloys 2019年第2期7卷 249-257页

作者： Aya mohamed ahmed MEl-Aziz Hans-Georg Breitinger Materials Engineering Department German University in Cairo(GUC)11835 New CairoEgypt Department of Biochemistry German University in Cairo(GUC)11835 New CairoEgypt

Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable *** study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Hank’s balanced salt solution(HBSS).Immersion,hydrogen evolution and electrochemical behavior was studied as well as the cytotoxicity of the degradation *** and phase composition of the corrosion products were studied using SEM,EDX and XRD *** in HBSS resulted in the formation of the needle-shaped carbonated hydroxyapatite which was similar to the biological apatite in the human *** kinetics showed that Mg-0.8Ca alloy had approximately 3-fold faster degradation rate than the pure Mg(1.08±0.38 mm/year for Mg-0.8Ca and 0.35±0.17 mm/year for pure Mg),as observed in two independent ***,pure Mg and Mg-0.8Ca alloy were biocompatible,generating no cytotoxic degradation products against human-derived HEK 293 ***,the Mg-0.8Ca alloy was found to be a promising biodegradable implant in terms of bioactivity and compatibility with human cell *** on the application of the implant and the estimated healing time of the bone,the desired degradation rate of an implant can be controlled by the Mg-Ca composition of such alloys.

关键词： Mg-Ca alloys Biodegradability Orthopedic implants Biocompatibility Toxicity Hydroxyapatite

Utilization of HEVC ChaCha20-Based Selective Encryption for Secure Telehealth Video Conferencing

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Computers, Materials & Continua 2022年第1期70卷 831-845页

作者： osama S.Faragallah ahmed I.Sallam Hala S.El-sayed Department of Information Technology College of Computers and Information TechnologyTaif UniversityP.O.Box 11099Taif21944Saudi Arabia Department of Computer Science and Engineering Faculty of Electronic EngineeringMenoufia UniversityMenouf32952Egypt Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Kom32511Egypt

Coronavirus(COVID-19)is a contagious disease that causes exceptional effect on healthcare organizationsworldwide with dangerous impact on medical services within the *** of the fast spread of COVID-19,the healthcare facilities could be a big source of disease ***,healthcare video consultations should be used to decrease face-to-face communication between clinician and *** video consultations may be beneficial for some COVID-19 conditions and reduce the need for faceto-face contact with a potentially positive patient without *** conditions are like top clinicians who provide remote consultations to develop treatment methodology and follow-up remotely,patients who consult about COVID-19,and those who have mild symptoms suggestive of the COVID-19 *** consultations are a supplement to,and not a substitute for,telephone *** may also form part of a broader COVID-19 distance care strategy that contains computerized screening,separation of possibly infectious patients within medical services,and computerized video-intensive observing of their intensive care that helps reduce ***,the spread of the COVID-19 virus helps to expand the use of video healthcare consultations because it helps to exchange experiences and remote medical consultations,save costs and health procedures used to cope with the pandemic of the COVID-19 virus,and monitor the progress of treatment plans,moment by moment from a distance with precision,clarity and *** this perspective,this paper introduces a high-efficiency video coding(HEVC)ChaCha20-based selective encryption(SE)scheme for secure healthcare video *** proposed HEVC ChaCha20-based SE scheme uses the ChaCha20 for encrypting the sign bits of the Discrete Cosine Transform(DCT)and Motion Vector Difference(MVD)in the HEVC entropy *** main achievement of HEVC ChaCha20-based SE scheme is encrypting the most sensitive video bits with keeping low

关键词： Telehealth HEVC cahcha20 video conferencing

New model for standpipe pressure prediction while drilling using Group Method of Data Handling

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Petroleum 2022年第2期8卷 210-218页

作者： mohamed Riad Youcefi ahmed Hadjadj Farouk Said Boukredera Laboratory of Petroleum Equipment’s Reliability and Materials Faculty of Hydrocarbons and ChemistryUniversity M’hamed Bougara of BoumerdesAvenue de l’Independance35000BoumerdesAlgeria

The continuous evaluation of the measured Stand Pipe Pressure(SPP)against a modeled SPP value in real-time involves the automatic detection of undesirable drilling events such as drill string washouts and mud pump *** theoretical and experimental studies have been established to calculate the friction pressure losses using different rheological models and based on an extension of pipe flow correlations to an annular ***,it would not be feasible to employ these models for real-time applications since they are limited to some conditions and intervals of application and require input parameters that might not be available in real-time on each *** this study,The Group Method of Data Handling(GMDH)is applied to develop a trustworthy model that can predict the SPP in real-time as a function of mud flow,well depth,RPM and the Fan VG viscometer reading at 600 and 300 *** order to accomplish the modeling task,3351 data points were collected from two wells from Algerian *** and statistical assessment criteria disclosed that the model predictions are in excellent agreement with the experimental data with a coefficient of determination of 0.9666 and an average percent relative error less than 2.401%.Furthermore,another dataset(1594 data points)from well-3 was employed to validate the developed correlation for *** obtained results confirmed that the proposed GMDH-SPP model can be applied in real-time to estimate the SPP with high ***,it was found that the proposed GMDH correlation follows the physically expected trends with respect to the employed input ***,the findings of this study can help for the early detection of downhole problems such as drill string washout,pump failure,and bit balling.

关键词： Stand pipe pressure GMDH Drilling Mud flow Real-time monitoring Drill string washouts

GIS-based flash flooding susceptibility analysis and water management in arid mountain ranges:Safaga Region,Red Sea Mountains,Egypt

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Journal of Mountain Science 2023年第12期20卷 3665-3686页

作者： ahmed E.EL-RAYES mohamed O.ARNOUS ahmed M.HELMY Geology Department Faculty of ScienceSuez Canal UniversityIsmailia 41522Egypt Geology Department Faculty of ScienceArish UniversityArish 45511 North SinaiEgypt

The Safaga Region(SR)is part of the Red Sea mountain range in *** flash flooding is now an inescapable event,wreaking havoc and causing massive loss of life and *** majority of the floodwater,however,has been wasted as runoff to the Red Sea,which,if used wisely,could meet a fraction of the water demands for a variety of applications in this *** current work aims to use GIS techniques to integrate remote sensing data for evaluating,mitigating,and managing flash floods in *** data set comprised Tropical Rainfall Measuring Mission(TRMM)thematic rainfall data,1:50,000 scale topographical map sheets,geological maps,the ASTER Digital Elevation Model(ASTER GDEM),Landsat 7 Enhanced Thematic Mapper"(ETM7+),and Landsat 8 Operational Land *** flash flood risk model of SR is developed using ArcGIS-10.3 geoprocessing tools integrating all the causal factors thematic *** final flood risk model for the SR suggests that 57%of the total basins in the SR are at high risk of *** 38%of all basins are at moderate flood *** remaining 5%of basins are less prone to ***-prone zones were identified,suitable dam-building sites were located,and extremely probable areas for water recharge were *** the basis of reliable scientific data,structural and non-structural mitigation strategies that might reduce the damage susceptibility,alleviate the sensitivity of the flash flood,and best utilize its water supply were recommended.

关键词： Flash floods GIS Susceptibility Water management Arid mountains Egypt

Molecular mechanisms of the anti-obesity potential effect of Moringa oleifera in the experimental model

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Asian Pacific Journal of Tropical Biomedicine 2017年第3期7卷 214-221页

作者： Fateheya mohamed Metwally Hend mohamed Rashad Hanaa Hamdy ahmed Asmaa ahmed Mahmoud Ehab Ragaa Abdol Raouf Aboelfetoh mohamed Abdalla Environmental and Occupational Medicine National Research CentreGizaEgypt Department of Hormones National Research CentreGizaEgypt Department of Zoology Faculty of ScienceAin Shams UniversityCairoEgypt Department of Research on Children with Special Needs National Research CentreGizaEgypt Department of Horticulture Crops Technology National Research CentreGizaEgypt

Objective: To elucidate the molecular mechanisms of the potent anti-obesity effect of Moringa oleifera Lam.(M. oleifera) ethanolic extract and to clarify the link between these mechanisms and the associated metabolic and vascular risks in the experimental model of visceral ***: M. oleifera ethanolic extract was orally administered at 600 mg/kg body weight in obese female rats daily for 12 weeks. At the end of treatment, body weight was determined, and the atherogenic index, coronary artery index, glucose level, insulin resistance status, liver and kidney functions were assessed. Also, the m RNA of leptin, adiponectin and resistin in visceral adipose tissue was determined by quantitative real ***: The results showed that M. oleifera extract down-regulated m RNA expression of leptin and resistin, while it up-regulated adiponectin gene expression in obese rats relative to untreated obese control counterparts. This amelioration of genes expression was paralleled by a reduction in body weight and improvement of the atherogenic index and coronary artery index, as well as glucose level and insulin resistance value without adverse effects on liver or kidney functions, versus the untreated obese control ***: It is reasonable to assume that the anti-obesity, anti-atherogenic and antidiabetic properties of M. oleifera are mechanistically achieved via working directly on the adipokines of the visceral adipose tissue. Therefore, M. oleifera may be a good therapeutic candidate for the symptoms of metabolic syndrome.

关键词： Moringa oleifera Lam Visceral adipose tissue Adipokines Gene expression Rats

Application of microalgal-ZnO-NPs for reusing polyester/cotton blended fabric wastes after modification by cellulases enzymes

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Waste Disposal and Sustainable Energy 2023年第4期5卷 471-482页

作者： osama M.Darwesh Naser G.Al-Balakocy ahmed Ghanem Ibrahim A.Matter Agricultural Microbiology Department National Research Centre33 EL-Buhouth St.DokkiCairo12622Egypt Protenic and Manmade Fibers Department National Research CentreDokkiCairo12622Egypt Packaging Materials Department National Research CentreCairo12622Egypt

Polyester/cotton(PET/C)blended fabric wastes are produced daily in huge amounts,which constitutes an economic loss and an environmental threat if it is not reused *** textile waste recycling technologies put much effort into developing fabric materials with unique properties,such as bioactivity or new optical goods based on modern technologies,especially *** this study,zinc oxide nanoparticles(ZnO-NPs)were biosynthesized using the aqueous extract of Dunaliella *** immobilized on PET/C waste fabrics after enzymatically activated with *** produced Dunaliella-ZnO-NPs(10–20 nm with a spherical shape)were characterized by High-resolution transmission electron microscopy(HRTEM),Fourier-transform infrared spectroscopy(FTIR),X-Ray diffraction analysis(XRD),and Scanning electron microscopy-energy dispersive X-ray analyzer(SEM-EDAX),and some functional groups,such as CH,CO,NH,and CN(due to the presence of carboxyl,proteins and hydroxyl groups),were detected,revealing the biosynthesis of *** analysis showed that the resulting ZnO-NPS had potent antimicrobial effects,Ultraviolet(UV)protection capabilities,and no cytotoxic effects on the normal human fibroblast cell line(BJ1).On the other hand,enzymatic treatments of PET/C fabric waste with cellulases enhanced the immobilization of biosynthetic nanoparticles on their *** PET/C fabrics loaded with Dunaliella-ZnO-NPs showed antibacterial and UV protection capabilities making them an eco-friendly and cost-effective candidate for numerous *** applications can include the manufacture of active packaging devices,wastewater treatment units,and many other environmental applications.

关键词： Wastewater remediation Polyester/cotton wastes Cytotoxicity Microalgal-ZnO-NPs Dunaliella sp. Microbial nanotechnology

Maximizing the Benefit of Rate Transient Analysis for Gas Condensate Reservoirs

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Energy Engineering 2021年第5期118卷 1411-1423页

作者： Mahmoud Abdo Tantawy ahmed A.M.Elgibaly ahmed mohamed Farag Faculty of Petroleum and Mining Engineering Suez UniversitySuezEgypt Abu Qir Petroleum Company AlexandriaEgypt

In recent years,many trials have been made to use the Rate Transient Analysis(RTA)techniques as a method to describe the gas condensate *** problem with using these techniques is the multi-phase behavior of the gas condensate ***,the Pressure Transient Analysis(PTA)is commonly used in this case to analyze the reservoir *** this paper,we are going to compare the results of both PTA and RTA of three wells in gas condensate *** comparison showed a great match between the results of the two mentioned techniques for the first time using a reference GOR of 75,000 SCF/***,we concluded that we could depend on RTA instead of PTA to spare the cost associated with the PTA in the gas condensate reservoirs.

关键词： Rate transient analysis production data analysis well testing permeability skin factor gas condensate

Modular Multilevel Converter with Wireless Magnetic Power Decoupling for Three-phase MV Adjustable-speed Drives

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CSEE Journal of Power and Energy Systems 2022年第5期8卷 1497-1507页

作者： mohamed Atef Tawfik Mohammad Sameer Irfan Ashraf ahmed Joung-Hu Park Department of Electrical Engineering Soongsil UniversitySeoul 156-743South Korea

In this paper,we propose a modular multilevel converter(MMC)with a wireless magnetic power decoupling approach suitable for medium-voltage high-power variable-speed machine *** proposed power decoupling approach is independent of the operating frequency,which solves the issue of wide fluctuations of low-frequency voltage ripple components in submodule(SM)capacitors,especially at low-speed operations without using any ripple power *** wireless magnetic elements reduces the amount of high-voltage insulation between the transformer windings,resulting in a significant reduction in the overall size of the *** basic idea of our proposed approach is to magnetically couple the instantaneous three-phase ripple power of each of the three adjacent-arm *** proposed MMC is free from low-frequency capacitors,resulting in enhanced system reliability,volume,and *** operation principles of the proposed MMC are explained,and a control design is *** performance of the proposed scheme was verified via simulation and experimental tests.

关键词： Modular multilevel converter power decoupling submodule capacitor voltage ripple variable-speed drives wireless high-frequency transformer