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Vascular endothelial growth factor:a double-edged sword in the development of white matter lesions

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Neural Regeneration Research 2025年第1期20卷 191-192页

作者： Narek Manukjan Daniel Fulton Zubair ahmed WMatthijs Blankesteijn sébastien Foulquier Department of Pharmacology and Toxicology Maastricht UniversityMaastrichtThe Netherlands CARIM-school for Cardiovascular Diseases Maastricht UniversityMaastrichtThe Netherlands Neuroscience and Ophthalmology Institute of Inflammation and AgeingUniversity of BirminghamEdgbastonBirminghamUK Centre for Trauma sciences Research University of BirminghamEdgbastonBirminghamUK MHeNs-school for Mental Health and Neuroscience Maastricht UniversityMaastrichtThe Netherlands Department of Neurology Maastricht University Medical CenterMaastrichtThe Netherlands

As the population ages,the burden of age-related diseases becomes ***,over 55 million people suffer from dementia worldwide,with Alzheimer’s disease being the most common ***,it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease(csVD)may be a more detrimental cause for dementia(Cuadrado-Godia et al.,2018).It is estimated that 10%-30%of the elderly population and 35%-90%of all dementia patients exhibit signs of *** term csVD refers to pathology affecting the small vessels of the brain,which can lead to lacunar cerebral infarcts,enlarged perivascular spaces,and cortical hemorrhages(Cuadrado-Godia et al.,2018).CsVD is often associated with cognitive decline,gait problems,and dementia(Cuadrado-Godia et al.,2018).

关键词： pathology becoming white

Nanosecond pulse and dual-wavelength Q-switched 1.5 μm fiber laser using MAX phase Cr2TiAlC2 saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： ahmed shakir AL-HITI Hiba HAssAN Department of Electrical Engineering Faculty of Engineering University of Anbar Department of Laser and Optoelectronics Engineering University of Technology-Iraq

We demonstrated a new type of MAX phase material, chromium titanium aluminum carbide（Cr2TiAlC2） polymer film, to generate a passively Q-switched erbium-doped fiber laser（EDFL）. The film thickness was measured to be around 45 μm, which was fabricated using the embedding method with polyvinyl alcohol（PVA） polymer as hoster. The saturable absorber（sA） film demonstrates a dual-wavelength passively Q-switched EDFL which operates at 1 531 nm and 1 560.19 nm, respectively. The Q-switching pulse duration could be varied from 2.46 μs to 770 ns, while the repetition rate varied from 92.76 kHz to 106.6 kHz with an increasing input pumping range from 154 mW to 300 mW. The maximum output power and pulse energy of 15.05 mW and 141.18 nJ were obtained at the maximum input power of 300 mW, respectively.

关键词： saturable absorbers

Modeling natural convection boundary layer flow of micropolar nanofluid over vertical permeable cone with variable wall temperature

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Applied Mathematics and Mechanics(English Edition) 2017年第8期38卷 1171-1180页

作者： s.E.ahmed Department of Mathematics Faculty of ScienceSouth Valley UniversityQena 83523Egypt

This paper discusses the natural convection boundary layer flow of a micropo- lax nanofluid over a vertical permeable cone with variable wall temperatures. Non-similax solutions are obtained. The nonlineaxly coupled differential equations under the boundary layer approximations governing the flow axe solved numerically using an efficient, itera- tive, tri-diagonal, implicit finite difference method. Different experimental correlations for both nanofluid effective viscosity and nanofluid thermal conductivity are considered. It is found that as the vortex-viscosity parameter increases, both the velocity profiles and the local Nusselt number decrease. Also, among all the nanoparticles considered in this investigation, Cu gives a good convection.

关键词： micropolar nanofluid non-similar solution cone finite difference method,non-uniform heating

Carbon nanotube-based nanoelectromechanical resonatoras mass biosensor

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Chinese Physics B 2020年第7期29卷 583-587页

作者： ahmed MElseddawy Adel HPhillips ahmed s Bayoumi Faculty of Graduate studies University of WindsorWindsorOntarioCanada Faculty of Engineering Ain-Shams UniversityCairoEgypt Faculty of Engineering Kafr-Elsheikh UnversityKafr-ElsheikhEgypt

The use of single walled carbon nanotube-based nanoelectromechanical system(NEMs)resonator to sense the biomolecules'mass is investigated under the influence of an external ac-field.A single walled carbon nanotube(sWCNT)cantilever has been proposed and studied if the mass is attached at the tip or various intermediate *** shift of the resonant frequency and the quality factor have been investigated and show high sensitivity to the attached mass of biomolecule and its *** proposed sWCNT-based NEMs resonator is a good candidate for sensing and tracing biomolecules'mass as concentration of acetone in human exhale,resulting in a painless,correct,and simple diabetics'diagnosis.

关键词： single walled carbon nanotube nanoelectromechanical system resonator ac-field biomolecule

Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling systems

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structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： sabrina Meddah sid ahmed Tadjer Abdelhakim Idir Kong Fah Tee Mohamed Zinelabidine Doghmane Madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

Intelligent Deep Learning Enabled Wild Forest Fire Detection system

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Computer systems science & Engineering 2023年第2期44卷 1485-1498页

作者： ahmed s.Almasoud Department of Information systems College of Computer and Information SciencesPrince Sultan UniversityRiyadh11586Saudi Arabia

The latest advancements in computer vision and deep learning(DL)techniques pave the way to design novel tools for the detection and monitoring of forestﬁ*** this view,this paper presents an intelligent wild forestﬁre detec-tion and alarming system using deep learning(IWFFDA-DL)*** pro-posed IWFFDA-DL technique aims to identify forestﬁres at earlier stages through integrated *** proposed IWFFDA-DL system includes an Inte-grated sensor system(Iss)combining an array of sensors that acts as the major input source that helps to forecast theﬁ***,the attention based convolution neural network with bidirectional long short term memory(ACNN-BLsTM)model is applied to examine and identify the existence of *** hyperpara-meter tuning of the ACNN-BLsTM model,the bacterial foraging optimization(BFO)algorithm is employed and thereby enhances the detection ***,when theﬁre is detected,the Global system for Mobiles(GsM)modem transmits messages to the authorities to take required *** extensive set of simulations were performed and the results are investigated interms of several *** obtained results highlight the betterment of the IWFFDA-DL techni-que interms of various measures.

关键词： Forestﬁre deep learning intelligent models metaheuristics integrated sensor system hyperparameter tuning

Laminar MHD natural convection of nanofluid containing gyrotactic microorganisms over vertical wavy surface saturated non-Darcian porous media

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Applied Mathematics and Mechanics(English Edition) 2016年第4期37卷 471-484页

作者： s.E.ahmed A.MAHDY Department of Mathematics Faculty of Sciences South Valley University

Magnetohydrodynamic （MHD） bioconvection of an incompressible electrically conducting nanofluid near a vertical wavy surface saturated porous medium containing both nanoparticle and gyrotactic microorganisms is investigated. The nanofluid is represented by a model that includes both Brownian motion and thermophoresis effects. A suitable set of non-dimensional variables are used to transform the governing boundary layer equations into a dimensionless form. The resulting nonlinear system is mapped to the vertical flat plate domain, and a non-similar solution is used to the obtained equations. The obtained non-similar system is then solved numerically using the fourth-order Runge-Kutta method. The influence of various physical parameters on the local Nusselt number, the local sherwood number, the local density number of the motile microorganisms, the dimensionless velocity, the dimensionless temperature, and the rescaled density of motile microorganisms is studied. It is found that the local Nusselt number, the local sherwood number, and the local density number of the motile microorganisms decrease by increasing either the Grashof number or the magnetic field parameter.

关键词： wavy surface nanofluid non-Darcy bioconvection boundary layer gyrotactic microorganism porous media

Effect of Colouring Process on Pitting susceptibility of Austenitic stainless steel

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Journal of Materials science & Technology 2008年第3期24卷 400-406页

作者： s.s.Mahmoud M.M.ahmed Chemistry Department University College of Girls for ArtsScience and EducationAin Shams University

Colouring of the austenitic stainless steel alloy （20.45% Cr, 8.57% Ni） was carried out in NaNO3-KNO3 eutectic melt without and with additions of Na2O2, NaCl and their mixtures at different temperatures ranging from 400-600℃, under open-circuit and galvanostatic anodic polarization conditions. The produced colours greatly depend on the thickness of oxide films, which in turn depends on the composition of the molten bath and its temperature. The more attractive, bright, adherent and uniform coloured oxide films can be obtained at 400, 450 and 500℃ in molten nitrate bath containing NaCl and Na2O2 mixtures. The pitting corrosion susceptibility of the coloured oxide films was tested in FeCl3 and NaCl as corrosive media. The obtained results indicate that the pitting corrosion susceptibility of the coloured oxide films greatly depends on the previous operating conditions of the colouring process of the stainless steel specimens such as the composition of molten bath, temperature and technique of colouring process.

关键词： stainless steel alloy Pitting corrosion Colouring processes

Effect of size and indium-composition on linear and nonlinear optical absorption of InGaN/GaN lens-shaped quantum dot

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Chinese Physics B 2016年第5期25卷 380-387页

作者： ahmed s Jbara Zulkafli Othaman M A saeed Center for sustainable Nanomaterials Universiti Teknologi Malaysia Physics Department Science College Al-Muthanna University Department of Physics Faculty of Science Universiti Teknologi Malaysia

Based on the schr ¨odinger equation for envelope function in the effective mass approximation, linear and nonlinear optical absorption coefficients in a multi-subband lens quantum dot are investigated. The effects of quantum dot size on the interband and intraband transitions energy are also analyzed. The finite element method is used to calculate the eigenvalues and eigenfunctions. strain and In-mole-fraction effects are also studied, and the results reveal that with the decrease of the In-mole fraction, the amplitudes of linear and nonlinear absorption coefficients increase. The present computed results show that the absorption coefficients of transitions between the first excited states are stronger than those of the ground states. In addition, it has been found that the quantum dot size affects the amplitudes and peak positions of linear and nonlinear absorption coefficients while the incident optical intensity strongly affects the nonlinear absorption coefficients.

关键词： linear and nonlinear optical absorption coefficients lens quantum dot finite element method