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Flow Rate through a Blood Vessel Deformed Due To a Uniform Pressure

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Journal of Biomaterials and Nanobiotechnology 2011年第4期2卷 369-377页

作者： Amy Cypher J mohamed B. elgindi Hatem Kouriachi David Peschman Reba Shotwell 不详

In this paper, we present the mathematical equations that govern the deformation of an imbedded blood vessel under external uniform pressure taking into consideration the nonliner behavior of the soft tissue surrounding the vessel. We present a bifurcation analysis and give explicit formulas for the bifurcation points and the corresponding first order approximations for the\emph{non-trivial} solutions. We then show the results of a MATLAB program that integrates the equilibrium equations and calculates the blood flow rate through a deformed cross section for given values of the elasticity parameters and pressure. Finally, we provide (numerical) verification that the flow rate as a function of the elasticity parameters of the soft tissue surrounding the blood vessel is convex, and therefore validate the invertibility of our model.

关键词： Blood Vessel Deformation of Elastic Tube

Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice

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Neural Regeneration Research 2025年第8期20卷 2348-2360页

作者： mohamed Aghyad Al Kabbani Christoph Köhler Hans Zempel Institute of Human Genetics Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany Center for Molecular Medicine Cologne(CMMC) University of CologneCologneGermany Center Anatomy Department ⅡMedical FacultyUniversity of CologneCologneGermany

TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the *** is missorted and aggregated in an array of diseases known as *** are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing *** impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule *** therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to *** investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-KO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic *** sum,P301L-TAU results in changes in micr

关键词： human induced pluripotent stem cell microtubules P301L pR5 mice TAU tauopathy tubulin code

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

Finite Element Analysis of the Ramberg-Osgood Bar

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American Journal of Computational Mathematics 2013年第3期3卷 211-216页

作者： Dongming Wei mohamed B. M. elgindi Department of Mathematics University of New Orleans New Orleans USA Texas A & M University-Qatar Doha Qatar

In this work, we present a priori error estimates of finite element approximations of the solution for the equilibrium equation of an axially loaded Ramberg-Osgood bar. The existence and uniqueness of the solution to the associated nonlinear two point boundary value problem is established and used as a foundation for the finite element analysis.

关键词： Nonlinear Two Point Boundary Value Problem Ramberg-Osgood Axial Bar Existence and Uniqueness of Solutions Finite Element Analysis Convergence and a Priori Error Estimates

Small heat shock protein B8:from cell functions to its involvement in diseases and potential therapeutic applications

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Neural Regeneration Research 2025年第10期20卷 2872-2886页

作者： Marta Chierichetti Riccardo Cristofani Valeria Crippa Veronica Ferrari Marta Cozzi Elena Casarotto Paola Pramaggiore Laura Cornaggia Guglielmo Patelli Ali mohamed Margherita Piccolella Mariarita Galbiati Paola Rusmini Barbara Tedesco Angelo Poletti Laboratory of Experimental Biology Dipartimento di Scienze Farmacologiche e Biomolecolari“Rodolfo Paoletti”(DiSFeB)Universitàdegli Studi di MilanoMilanItaly

Heat shock protein family B(small)member 8(HSPB8)is a 22 kDa ubiquitously expressed protein belonging to the family of small heat shock ***8 is involved in various cellular mechanisms mainly related to proteotoxic stress response and in other processes such as inflammation,cell division,and ***8 binds misfolded clients to prevent their aggregation by assisting protein refolding or degradation through chaperone-assisted selective *** line with this function,the pro-degradative activity of HSPB8 has been found protective in several neurodegenerative and neuromuscular diseases characterized by protein misfolding and *** cancer,HSPB8 has a dual role being capable of exerting either a pro-or an anti-tumoral activity depending on the pathways and factors expressed by the model of cancer under ***,HSPB8 exerts a protective function in different diseases by modulating the inflammatory response,which characterizes not only neurodegenerative diseases,but also other chronic or acute conditions affecting the nervous system,such as multiple sclerosis and intracerebellar *** note,HSPB8 modulation may represent a therapeutic approach in other neurological conditions that develop as a secondary consequence of other *** is the case of cognitive impairment related to diabetes mellitus,in which HSPB8 exerts a protective activity by assuring mitochondrial *** review aims to summarize the diverse and multiple functions of HSPB8 in different pathological conditions,focusing on the beneficial effects of its ***-based and alternative therapeutic approaches targeting HSPB8 and its regulated pathways will be discussed,emphasizing how new strategies for cell and tissue-specific delivery represent an avenue to advance in disease treatments.

关键词： aggregation autophagy cancer chaperone chaperone-assisted selective autophagy cognitive impairment HSPB8 neuroinflammation neuromuscular diseases therapy

A Note on the Proof of the Perron-Frobenius Theorem

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Applied Mathematics 2012年第11期3卷 1697-1701页

作者： Yun Cheng Timothy Carson mohamed B. M. elgindi exas A&M University—Qatar Doha Qatar University of Chicago Chicago USA University of Texas Austin USA

This paper provides a simple proof for the Perron-Frobenius theorem concerned with positive matrices using a homotopy technique. By analyzing the behaviour of the eigenvalues of a family of positive matrices, we observe that the conclusions of Perron-Frobenius theorem will hold if it holds for the starting matrix of this family. Based on our observations, we develop a simple numerical technique for approximating the Perron’s eigenpair of a given positive matrix. We apply the techniques introduced in the paper to approximate the Perron’s interval eigenvalue of a given positive interval matrix.

关键词： Perron Eigenpair Homotopy Eigencurves Positive Matrices Interval Matrices

Mixed sensitivity H_∞ control for LTI systems with varying time delays

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Journal of Systems Engineering and Electronics 2018年第3期29卷 611-617页

作者： OULD mohamed mohamed vall College of Computer and Information Sciences Al Jouf University

Designing a robust controller for a system with timevarying delays poses a major challenge. In this paper, we propose a method based on mixed sensitivity H∞ for the control of linear time invariant（LTI） systems with varying time delays. The time delay is assumed bounded and the upper bound is known. In the technique we propose, the delay affecting the plant to be controlled is treated as an unmodeled uncertainty（in form of multiplicative uncertainty）. That uncertainty is approximated and then an H∞based controller, for the plant represented by the multiplicative uncertainty and the nominal model, is calculated. The obtained H∞controller is used to control the LTI systems with varying time delays. Simulation examples are given to illustrate the effectiveness of the proposed method.

关键词： linear time invariant(LTI) systems mixed sensitivity H∞ varying time delay unmodeled uncertainty H∞ control

On the Buckling of Euler Graphene Beams Subject to Axial Compressive Load

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World Journal of Engineering and Technology 2014年第2期2卷 149-158页

作者： mohamed B. M. elgindi Dongming Wei Yeran Soukiassian Yu Liu Department of Electrical Engineering University of New Orleans Louisiana USA Department of Mathematics Texas A & M University-Qatar Doha Qatar Department of Mathematics University of New Orleans Louisiana USA

In this paper, we consider the buckling of an Euler-Bernoulli graphene beam due to an axial compressive load. We formulate the problem as a non-linear (eigenvalue) two-point boundary value problem, prove some properties of the eigenpairs and introduce a suitable numerical shooting method scheme for approximating them. We present the perturbation and the numerical approximations of the first and second buckling loads and the corresponding shapes.

关键词： Critical Buckling Load Graphene Euler-Bernoulli Beam Non-Linear Eigenvalue Problem Shooting Method

Fixed-time Distributed Voltage and Reactive Power Compensation of Islanded Microgrids Using Sliding-mode and Multi-agent Consensus Design

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Journal of Modern Power Systems and Clean Energy 2022年第1期10卷 232-240页

作者： mohamed Ghazzali mohamed Haloua Fouad Giri Electrical Engineering Department Mohammadia School of EngineersUniversity Mohammed VRabatMorocco Caen Automation Laboratory(LAC) Caen Normandie University(UNICAEN)CaenFrance

This paper investigates a fixed-time distributed voltage and reactive power compensation of islanded microgrids using sliding-mode and multi-agent consensus design.A distributed sliding-mode control protocol is proposed to ensure voltage regulation and reference tracking before the desired preset fixed-time despite the unknown *** reactive power sharings among distributed generators are *** secondary controller is synthesized without the knowledge of any parameter of the *** is implemented using a sparse one-way communication network modeled as a directed graph.A comparative simulation study is conducted to highlight the performance of the proposed control strategy in comparison with finite-time and asymptotic control systems with load power variations.

关键词： Secondary controller microgrids reactive power control voltage control