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Emerging insights into the function of very long chain fatty acids at cerebellar synapses

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Neural Regeneration Research 2025年第6期20卷 1709-1710页

作者： Martin-Paul Agbaga Mohiuddin ahmad Department of Cell Biology and Ophthalmology University of Oklahoma Health Sciences Centerand Dean McGee Eye InstituteOklahoma CityOKUSA

Very long chain-saturated and-polyunsaturated fatty acids(VLC-SFA and VLC-PUFA, respectively) are a functionally important class of fatty acids containing 28 carbons or more in their acyl chain. They are synthesized by the elongation of very long fatty acids-4(ELOVL4) enzyme, expressed mainly in the brain, retina, skin, testes, and meibomian gland, where these fatty acids are found(Agbaga et al., 2008). Further, these organs exhibit tissuespecific VLC-PUFA and VLC-SFA biosynthesis and incorporation into complex lipids for specific functions. In the brain, skin, and Meibomian glands, the ELOVL4 mainly makes VLC-SFA, which are incorporated into complex sphingolipids. In the retina, the ELOVL4 makes VLC-PUFA that are incorporated into phosphatidylcholine, that are critical for visual function, while in testes and sperm, the VLC-PUFA are incorporated into sphingolipids that are critical for fertility(Yeboah et al., 2021).

关键词： functions function insight

Robust design of sliding mode control for airship trajectory tracking with uncertainty and disturbance estimation

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Journal of Systems Engineering and Electronics 2024年第1期35卷 242-258页

作者： WASIM Muhammad ALI Ahsan choudhry mohammad ahmad SHAIKH Inam Ul Hasan SALEEM Faisal Department of Aeronautics and Astronautics Engineering Institute of Space TechnologyIslamabad 44000Pakistan Department of Electrical Engineering University of Engineering and TechnologyTaxila 47080Pakistan Department of Measurements and Control Systems Silesian University of TechnologyGliwice 44-101Poland The Joint Doctoral School Silesian University of TechnologyGliwice 44-100Poland

The robotic airship can provide a promising aerostatic platform for many potential *** applications require a precise autonomous trajectory tracking control for *** has a nonlinear and uncertain *** is prone to wind disturbances that offer a challenge for a trajectory tracking control *** paper addresses the airship trajectory tracking problem having time varying reference path.A lumped parameter estimation approach under model uncertainties and wind disturbances is opted against distributed *** uses extended Kalman filter(EKF)for uncertainty and disturbance *** estimated parameters are used by sliding mode controller(SMC)for ultimate control of airship trajectory *** comprehensive algorithm,EKF based SMC(ESMC),is used as a robust solution to track airship *** proposed estimator provides the estimates of wind disturbances as well as model uncertainty due to the mass matrix variations and aerodynamic model *** stability and convergence of the proposed method are investigated using the Lyapunov stability *** simulation results show that the proposed method efficiently tracks the desired *** method solves the stability,convergence,and chattering problem of SMC under model uncertainties and wind disturbances.

关键词： airship chattering extended Kalman filter(EKF) model uncertainties estimation sliding mode controller(SMC)

Thermospheric neutral wind studies over the equatorial region:A review

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Earth and Planetary Physics 2025年第1期9卷 81-100页

作者： Siti Syazwani Nasuha Idahwati Sarudin Nurul Shazana Abdul Hamid ahmad Fairuz Omar School of Physics Universiti Sains Malaysia11800 USMPulau PinangMalaysia Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia Space Science Centre(ANGKASA) Institute of Climate ChangesUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia

Thermospheric neutral winds(TNWs)refer to the neutral gases in the thermosphere circulating as tides,which play a crucial role in the dynamics of the thermosphere-ionosphere system(TIS).Global geospace neutral winds,particularly over the magnetic equator,have been a subject of study for several ***,despite the known importance of neutral winds,a comprehensive understanding and characterization of the winds is still *** ground-based and satellite missions have provided valuable information on the contribution of neutral winds to the global atmospheric ***,efforts in the global monitoring of neutral winds are still lacking,and the drivers behind the behavior of TNWs as well as their influence on the TIS remain *** address these knowledge gaps in the global circulation of TNWs,it is crucial to develop a deep understanding of the neutral wind characteristics over different *** low-latitude equatorial region in particular has been observed to exert complex influences on TNWs because of the unique effects of the Earth’s magnetic field at the dip *** neutral winds over this region will provide valuable insights into the unique dynamics and processes that occur in this region,thereby enhancing our understanding of their role in the overall dynamics of the ***,through empirical observations,an improved ability to accurately model and predict the behavior of this region can be *** review article addresses challenges in understanding equatorial winds by reviewing historical measurements,current missions,and the interactions of ionospheric and thermospheric phenomena,emphasizing the need for comprehensive measurements to improve global atmospheric dynamics and weather forecasting.

关键词： thermospheric neutral wind thermosphere-ionosphere system dip equator equatorial region

Risk factors for congenital nasolacrimal duct obstruction in children under two years of age

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国际眼科杂志 2025年第1期25卷 17-23页

作者： Rozhin Kasiri Gholamreza Khataminia Ali Kasiri mohammad Sadegh Mirdehghan mohammad Armin Kasiri Infectious Ophthalmologic Research Center Ahvaz Jundishapur University of Medical SciencesAhvaz ***Iran Islamic Azad University Tehran Medical Sciences Tehran ***Iran

·AIM:To identify various risk factors that may play a significant role in the development of congenital nasolacrimal duct obstruction(CNLDO).·METHODS:This observational case-control study included a case group of 122 children less than two years of age with CNLDO who underwent probing and irrigation treatment at the ophthalmology department of Imam Khomeini Hospital in Ahvaz,Iran,from June 2022 to June2024.A control group of 122 age-matched children without CNLDO was also included for *** was collected from the children's medical records.·RESULTS:The study found a significant correlation between the occurrence of CNLDO and several maternal factors,such as preeclampsia,the use of levothyroxine,hypothyroidism,having more than three pregnancies(gravidity>3),natural pregnancy,and gestational diabetes ***,in children,factors,such as oxygen therapy,anemia,reflux,jaundice,and a family history of CNLDO in first-degree relatives were associated with CNLDO,and maternal preeclampsia and hypothyroidism were found to significantly increase the risk of developing CNLDO in children.·CONCLUSION:Given that CNLDO affects both premature and full-term children,the present findings may potentially facilitate the early identification of children and infants at risk of nasolacrimal duct obstruction,thereby preventing the onset of chronic dacryocystitis.

关键词： risk factors congenital nasolacrimal duct obstruction children

Diffusion of Six-Atom Cu Islands on Cu(111)and Ag(111)

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Chinese Physics Letters 2011年第5期28卷 99-102页

作者： Sardar Sikandar Hayat I.ahmad M.Arshad choudhry Department of Physics and Astronomy Hazara UniversityMansehra 23100Pakistan Department of Physics The Islamia University of BahawalpurBahawalpur 63120Pakistan

Diffusion of Cu hexamer islands on Cu(111)and Ag(111)is studied using a molecular dynamics simulation technique with many-body potentials obtained from the embedded atom *** are carried out at temperatures 300,500 and 700 K,showing that shape-changing multiple-atom processes are more helpful for the diffusion rather than concerted motion of *** plots of the diffusion coefficients provide effective energy barrier values of 161.29±5 meV for Cu(111)and 179.34±5 meV for Ag(111)*** 700K,one pop-up atom among island atoms is observed with correlative changes in the position and shape of the lower-layer adatoms.

关键词： Cu(111) method Diffusion

An Efficient EMD-Based Reversible Data Hiding Technique Using Dual Stego Images

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Computers, Materials & Continua 2023年第4期75卷 1139-1156页

作者： ahmad A.mohammad Princess Sumaya University for Technology Amman11941Jordan

Exploiting modification direction(EMD)based data hiding techniques(DHTs)provide moderate data hiding capacity and high-quality stego *** overflow problem and the cyclic nature of the extraction function essentially hinder their application in several fields in which reversibility is *** far,the few EMD reversible DHTs are complex and numerically *** paper presents a novel EMD-based reversible DHT using *** novel 2×4 modification lookup tables are introduced,replacing the 256×256 reference matrix used in similar techniques and eliminating the numerically demanding search step in similar *** the embedding step,one of the modification tables modifies a pixel in odd columns in the first cover image and keeps its image in the second cover image *** other modification table modifies a pixel in even columns in the second cover image and keeps its image in the first cover image *** embedding strategy enables direct reversibility at almost zero computational *** technique embeds one 4−ary secret digit into each pixel in the first cover image and its image in the second cover image resulting in one bit per pixel(bpp)data embedding *** use of the 4−ary numbering system enables direct and numerically efficient conversion of the binary secret message to the 4−ary and vice *** advantages of the proposed algorithm are straightforward reversibility,simplicity,numerical efficiency,direct conversion of the binary secret message to 4−ary and vice versa,and elimination of the need for the 256×256 reference matrix by replacing it with two 2×4 lookup *** results show that the embedding rate of the proposed technique is one *** achieved more than 49 dB average Peak to Signal Noise Ratio(PSNR)over all test images.

关键词： Reversible data-hiding EMD-based high capacity steganography

Optimization of Manganese and Magnesium Contents in As-cast Aluminum-Zinc-Indium Alloy as Sacrificial Anode

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Journal of Materials Science & Technology 2011年第9期27卷 785-792页

作者： mohammad R. Saeri ahmad Keyvani Materials Engineering Division Faculty of Engineering Shahrekord University

In this study, effects of manganese and magnesium content on the electrochemical properties of Al-Zn-ln sacrificial anode were studied in 0.5 mol/L NaCl solution （pH=5）. The aluminum base alloy with different amounts of Mn and Mg were melted at 750℃, then casted at molds at 25℃. Corrosion experiments were mounted to determine the optimal effect of Mn and Mg on the efficiencies of the aluminum alloy anodes. The corroded and unexposed sample surfaces were subjected to microstructure characterization by optical and scanning electron microscopy. AI-Zn-ln alloy doped with 0%, 0.01%, 0.05%.0.2% and 0.3% by weights of Mn and 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0% by weights of Mg were prepared to determine the effect of Mn and Mg on anode efficiency in the environment. The different microstructures of the evolved AI- Zn-ln-Mg-Mn alloy were correlated with the anode efficiencies. The Al-5.0%Zn-2.0%Mg-0.15%Mn-0.02%ln gave the best anode efficiency （about 83%）. The microstructures of the corroded surface of the optimized alloy revealed decreased distribution of the pockets of localized attacks which are characteristics of pitting （or crevice） corrosion.

关键词： Corrosion Aluminum alloy Sacrificial anode Manganese Magnesium Current capacity

An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous media

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Frontiers of Structural and Civil Engineering 2021年第4期15卷 914-936页

作者： mohammad REZANEZHAD Seyed ahmad LAJEVARDI Sadegh KARIMPOULI Mining Engineering Group Faculty of EngineeringUniversity of ZanjanZanjan45371-38791Iran Materials Engineering Group Faculty of EngineeringUniversity of ZanjanZanjan45371-38791Iran

Crack growth modeling has always been one of the major challenges in fracture *** all numerical methods,the extended finite element method(XFEM)has recently attracted much attention due to its ability to estimate the discontinuous deformation ***,XFEM modeling does not directly lead to reliable results,and choosing a strategy of implementation is inevitable,especially in porous *** this study,two prevalent XFEM strategies are evaluated:a)applying reduced Young’s modulus to pores and b)using different partitions to the model and enriching each part *** mention the advantages and limitations of each strategy via both analytical and experimental ***,the crack growth is modeled in a natural porous media(Fontainebleau sandstone).Our investigations proved that although both strategies can identically predict the stress distribution in the sample,the first strategy simulates only the initial crack propagation,while the second strategy could model multiple cracks *** strategies are reliable and highly accurate in calculating the stress intensity factor,but the second strategy can compute a more reliable reaction *** tests showed that the second strategy is a more accurate strategy in predicting the preferred crack growth path and determining the maximum strength of the sample.

关键词： numerical modeling extended finite element method porous media crack growth stress intensity factor

Complete Moment Convergence for the Dependent Linear Processes with Random Coefficients

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Acta Mathematica Sinica,English Series 2019年第8期35卷 1321-1333页

作者： Seyed mohammad HOSSEINI ahmad NEZAKATI Faculty of Mathematical Sciences Shahrood University of Technology

In this paper, we investigate the complete moment convergence for dependent linear processes with random coefficients to form Xt =∑j^∞=∞ Aj∈t-j,where {∈n, n ∈ Z} is a sequence of END stochastically dominated random variables and {An,n ∈ Z} is a sequence of random varibles. As applications, the convergence rate, Marcinkiewicz-Zvgmund strong law and strong law of large numbers for this linear process are established.

关键词： Complete moment convergence ext ended negatively dependen t random variables linear processes random coefficients