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Current perspectives of nanoparticles in medical and dental biomaterials

The Journal of Biomedical Research 2012年第3期26卷 143-151页

作者： ibrahim mohamed hamouda Department of Dental Biomaterials and Restorative Dentistry Faculty of Dentistry Mansoura University Mansoura Dakahleya 35516 Egypt

Nanotechnology is gaining tremendous impetus due to its capability of modulating metals into their nanosize, which drastically changes the chemical, physical and optical properties of metals. Nanoparticles have been intro- duced as materials with good potential to be extensively used in biological and medical applications. Nanoparticles are clusters of atoms in the size range of 1-100 nm. Inorganic nanoparticles and their nano-composites are applied as good antibacterial agents. Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, pharmaceutical companies and researchers are searching for new antibacterial agents. The metallic nanoparticles are the most promising as they show good antibacterial properties due to their large surface area to volume ratios, which draw growing interest from researchers due to increasing microbial resistance against metal ions, antibiotics and the development of resistant strains. Metallic nanoparticles can be used as effective growth inhibitors in various microorganisms and thereby are applicable to diverse medical devices. Nanotechnology discloses the use of elemental nanoparticles as active antibacterial ingredient for dental materials. In dentistry, both restorative materials and oral bacteria are believed to be responsible for restoration failure. Secondary caries is found to be the main reason to restoration failure. Secondary caries is primarily caused by invasion of plaque bacteria （acid-producing bacteria） such as Streptococcus mutans and lactobacilli in the presence of fermentable carbohydrates. To make long-lasting restorations, antibacterial materials should be made. The potential of nanoparticles to control the formation of biofilms within the oral cavity is also coming under in- creasing scrutiny. Possible uses of nanoparticles as topically applied agents within dental materials and the appli- cation of nanoparticles in the control of oral infection

关键词： nanoparticles nano-medicine nano-biomaterials nanotechnology antibacterial agent

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Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin

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The Journal of Biomedical Research 2013年第2期27卷 151-158页

作者： Abdelraheem mohamed Ali ibrahim mohamed hamouda mohamed Hamed Ghazy Manal mohamed Abo-Madina Department of Conservative Dentistry Faculty of Dentistry Mansoura University Department of Dental Biomaterials Faculty of Dentistry Mansoura University Department of Conservative Dentistry Faculty of Dentistry Umm Al Qura University Crown & Bridge Department of Conservative Dentistry Faculty of Dentistry Mansoura University

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin （1 mm below the dentine-enamel junction）, deep dentin （1 mm above the highest pulp horn） and cervical dentin （0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction）. Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mrn/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin （P 〈 0.001）. Micro-ten- sile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions （P 〈 0.001）. Immediate ＂micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements （P 〈 0.001）. It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.

关键词： immediate and delayed micro-tensile bond strength luting resin cements regional dentin

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Laterites-bearing REEs,Wadi Natash,Southeastern Desert,Egypt

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Journal of Rare Earths 2010年第3期28卷 471-476页

作者： mohamed El-Ahmady ibrahim Nuclear Materials Authority P.O.Box530EL MaadiCairoEgypt

The present paper recorded the occurrence of laterites-bearing REEs in Natash *** laterite deposits occur as horizons(5-15 m in thickness) at the boundary between the Cretaceous sandstones,and Natash *** was recorded in more than twenty six occurrence distributed over an area of about 500 km2 along and around Wadi *** ranges in color from light-grey,dark-grey to *** distribution of laterite deposits is structural *** results of laterites proved the...

关键词： Natash flows laterites clay minerals REEs

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Wear properties of copper and copper composites powders consolidated by high-pressure torsion

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Friction 2020年第2期8卷 433-450页

作者： mohamed ibrahim Abd El AAL Mechanical Engineering Department College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addawaser 11991Saudi Arabia Mechanical Design&Production Department Faculty of EngineeringZagazig UniversityZagazig 44519Egypt

The wear characteristics of Cu and Cu-SiC composite microsize powders consolidated by cold compaction combined with sintering or high-pressure torsion(HPT)were *** HPT processed(HPTed)samples with bimodal and trimodal microstructures and fine Cu grains and SiC particle sizes have superior hardness,reasonable ductility level,and high wear *** wear mass loss and coefficient of friction of HPTed samples were remarkably lower than that of cold-compacted and sintered samples as well as that of micro and nano Cu and Cu-SiC composites from previous *** sample fabrication method has an apparent influence on the wear *** wear mechanism was converted from adhesive,delamination,three-body mechanism,grooves(take off the SiC particles),and cracks into abrasive wear after *** can be considered a dominant wear mechanism in all *** worn surface morphology and analysis support the relationship between wear mechanism and characteristics.

关键词： Cu-SiC composite powders high-pressure torsion(HPT) fine and coarse grains wear characteristics worn surface morphology

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Revolutionizing diabetic retinopathy screening and management:The role of artificial intelligence and machine learning

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World Journal of Clinical Cases 2025年第5期13卷 1-12页

作者： Mona mohamed ibrahim Abdalla Jaiprakash Mohanraj Department of Human Biology School of MedicineInternational Medical UniversityBukit Jalil 57000Kuala LumpurMalaysia

Diabetic retinopathy(DR)remains a leading cause of vision impairment and blindness among individuals with diabetes,necessitating innovative approaches to screening and *** editorial explores the transformative potential of artificial intelligence(AI)and machine learning(ML)in revolutionizing DR *** and ML technologies have demonstrated remarkable advancements in enhancing the accuracy,efficiency,and accessibility of DR screening,helping to overcome barriers to early *** technologies leverage vast datasets to identify patterns and predict disease progression with unprecedented precision,enabling clinicians to make more informed ***,AI-driven solutions hold promise in personalizing management strategies for DR,incorpo-rating predictive analytics to tailor interventions and optimize treatment *** automating routine tasks,AI can reduce the burden on healthcare providers,allowing for a more focused allocation of resources towards complex patient *** review aims to evaluate the current advancements and applic-ations of AI and ML in DR screening,and to discuss the potential of these techno-logies in developing personalized management strategies,ultimately aiming to improve patient outcomes and reduce the global burden of *** integration of AI and ML in DR care represents a paradigm shift,offering a glimpse into the future of ophthalmic healthcare.

关键词： Diabetic retinopathy Artificial intelligence Machine learning Screening Management Predictive analytics Personalized medicine

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Maxillary denture flange and occlusal discrepancies of Vertex ThermoSens in comparison with conventional heat-cured denture base materials

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The Journal of Biomedical Research 2019年第2期33卷 139-144页

作者： Hanadi A.Lamfon ibrahim M.hamouda Maxillofacial and Oral Rehabilitation Department Umm Al-Qura University Conservative Dentistry Faculty of Dentistry Umm Al-Qura University Dental Biomaterials Faculty of Dentistry Mansoura University

This study was conducted to investigate the maxillary denture bases and occlusal discrepancies using the Vertex Thermosens in comparison with the conventional polymethyl-methacrylate materials. Twenty maxillary denture bases were prepared from the Vertex ThermoSens and a conventional heat-cured denture base materials. Acrylic maxillary second molars were arranged in their respective positions on the ridge. After curing of both types of denture bases, they were deflasked with their respective master casts. Reference points were prepared for measurements of the antero-posterior and cross-arch dimensions at the denture borders using caliper device. Furthermore, the teeth discrepancies were measured between reference points in the ligual aspect of the second maxillary molars. The recorded data was analyzed using SPSS statistical software version 20. The results showed initial shrinkage of both denture bases in the antero-posterior and cross-arch dimensions immediately after decasting. This contraction was compensated gradually during storage in water up to 2 weeks. Regarding the variable time, there was a significant difference between the tested materials. Moreover, the results revealed occlusal discrepancies and shifting of teeth inward immediately after decasting, followed by outward movement after storage in water for 2 weeks. Regarding the variables time and materials, there were significant differences. Both materials exhibited inward shrinkage in the antero-posterior and cross-arch dimensions immediately after decasting. Both denture bases showed inward shifting of teeth immediately after decasting, followed by outward movement after storage in water up to 2 weeks.

关键词： denture distortion flange discrepancy acrylic resin occlusal discrepancies denture base

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Intelligent Beetle Antenna Search with Deep Transfer Learning Enabled Medical Image Classification Model

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Computer Systems Science & Engineering 2023年第9期46卷 3159-3174页

作者： mohamed ibrahim Waly Department of Medical Equipment Technology College of Applied Medical SciencesMajmaah UniversityAl Majmaah11952Saudi Arabia

Recently,computer assisted diagnosis(CAD)model creation has become more dependent on medical picture *** is often used to identify several conditions,including brain disorders,diabetic retinopathy,and skin *** traditional CAD methods relied on textures,colours,and *** many models are issue-oriented,they need a more substantial capacity to generalize and cannot capture high-level problem domain *** deep learning(DL)models have been published,providing a practical way to develop models specifically for classifying input medical *** paper offers an intelligent beetle antenna search(IBAS-DTL)method for classifying medical images facilitated by deep transfer *** IBAS-DTL model aims to recognize and classify medical pictures into various *** order to segment medical pictures,the current IBASDTLM model first develops an entropy based weighting and first-order cumulative moment(EWFCM)***,the DenseNet-121 techniquewas used as a module for extracting *** an extreme learning machine(ELM)model is used to classify the medical photos.A wide variety of tests were carried out using a benchmark medical imaging dataset to demonstrate the IBAS-DTL model’s noteworthy *** results gained indicated the IBAS-DTL model’s superiority over its pre-existing techniques.

关键词： Medical image segmentation image classification decision making computer aided diagnosis deep learning

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Generalized thermoelasticity of the thermal shock problem in an isotropic hollow cylinder and temperature dependent elastic moduli

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Chinese Physics B 2012年第1期21卷 289-294页

作者： ibrahim A.Abbas mohamed I.A.Othman Department of Mathematics Faculty of Science and Arts-KhulaisKing AbdulAziz UniversityJeddahSaudi Arabia Department of Mathematics Faculty of ScienceSohag UniversitySohagEgypt Department of Mathematics Faculty of ScienceZagazig UniversityP.O.Box 44519ZagazigEgypt

In this paper, we construct the equations of generalized thermoelasicity for a non-homogeneous isotropic hollow cylider with a variable modulus of elasticity and thermal conductivity based on the Lord and Shulman theory. The problem has been solved numerically using the finite element method. Numerical results for the displacement, the temperature, the radial stress, and the hoop stress distributions are illustrated graphically. Comparisons are made between the results predicted by the coupled theory and by the theory of generalized thermoelasticity with one relaxation time in the cases of temperature dependent and independent modulus of elasticity.

关键词： generalized thermoelsticity thermal shock temperature dependent elastic moduli finiteelement method

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Direct Power Control Based on Dead-beat Function and Extended Kalman Filter for PV Systems

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Journal of Modern Power Systems and Clean Energy 2023年第3期11卷 863-872页

作者： Mostafa Ahmed ibrahim Harbi Ralph Kennel mohamed Abdelrahem Chair of High-Power Converter Systems(HLU) Technical University of Munich(TUM)80333 MunichGermany Department of Electrical Engineering Faculty of EngineeringAssiut UniversityAssiut 71515Egypt Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Koum 32511Egypt IEEE

In this paper,a new proposal for the implementation of the well-known direct power control(DPC)technique in grid-connected photovoltaic(PV)systems is ***,the DPC is executed using a look-up table procedure based on the error between the actual and reference values of the active and reactive ***,the structure of the DPC is simple and results in a fast transient behavior of the inner current loop(injected currents).Therefore,in the current study,the DPC is reformulated using a dead-beat *** this formulation,the reference voltage vector(RVV)is obtained in theα-βreference ***,the switching states for the inverter can be obtained based on the sign of the components of the *** suggested DPC is compared with the conventional one and other switching tables,which are intended for performance ***,an extended Kalman filter(EKF)is utilized to eliminate all grid-voltage ***,the switching frequency of the proposed technique is minimized without any need for weighting factors or cost function *** overall control technique is validated using a hardware-in-the-loop(HIL)experimental set-up and compared with other schemes under different operating conditions.

关键词： Photovoltaic(PV)system direct power control(DPC) sensorless control switching frequency minimization weighting factor

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Automated classification technique for edge-on galaxies based on mathematical treatment of brightness data

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Research in Astronomy and Astrophysics 2021年第10期21卷 231-238页

作者： mohamed Eassa ibrahim mohamed Selim Walid Dabour Passent Elkafrawy Computer Science Department Integrated Thebes InstituteCairoEgypt Faculty of Computer&Artificial Intelligence Sadat City UniversitySadat CityEgypt Math and Computer Science Dept. Faculty of ScienceMenoufia UniversityEgypt Computer Science Dept. Taibah UniversityAlula BranchKingdom of Saudi Arabia School of Information Technology and Computer Science(ITCS) Nile UniversityEgypt

Classification of edge-on galaxies is important to astronomical studies due to our Milky Way galaxy being an edge-on ***-on galaxies pose a problem to classification due to their less overall brightness levels and smaller numbers of *** the current work,a novel technique for the classification of edge-on galaxies has been *** technique is based on the mathematical treatment of galaxy brightness data from their images.A special treatment for galaxies’brightness data is developed to enhance faint galaxies and eliminate adverse effects of high brightness backgrounds as well as adverse effects of background bright stars.A novel slimness weighting factor is developed to classify edge-on galaxies based on their *** technique has the capacity to be optimized for different catalogs with different brightness *** the current work,the developed technique is optimized for the EFIGI catalog and is trained using a set of 1800 galaxies from this *** classification of the full set of 4458 galaxies from the EFIGI catalog,an accuracy of 97.5% has been achieved,with an average processing time of about 0.26 seconds per galaxy on an average laptop.

关键词： techniques:image processing methods:data analysis galaxies:formation

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