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On Two Extension Formulas for Lauricella’s Function of the Second Kind of Several Variables
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作者 Ahmed Ali Atash Ahmed Ali Al-Gonah 《Journal of Applied Mathematics and Physics》 2016年第3期571-577,共7页
The aim of this research paper is to derive two extension formulas for Lauricella’s function of the second kind of several variables with the help of generalized Dixon’s theorem on the sum of the series  obtain... The aim of this research paper is to derive two extension formulas for Lauricella’s function of the second kind of several variables with the help of generalized Dixon’s theorem on the sum of the series  obtained by Lavoie et al. [1]. Some special cases of these formulas are also deduced. 展开更多
关键词 Extension Formulas lauricella’s function Dixon’s Theorem Hypergeometric functions
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Transformation Formulas for the First Kind of Lauricella’s Function of Several Variables
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作者 Fadhle B. F. Mohsen Ahmed Ali Atash Hussein Saleh Bellehaj 《Journal of Applied Mathematics and Physics》 2016年第6期1112-1119,共8页
Very recently Atash and Al-Gonah [1] derived two extension formulas for Lauricella’s function of the second kind of several variables and . Now in this research paper we derive two families of transformation formulas... Very recently Atash and Al-Gonah [1] derived two extension formulas for Lauricella’s function of the second kind of several variables and . Now in this research paper we derive two families of transformation formulas for the first kind of Lauricella’s function of several variables and with the help of generalized Dixon’s theorem on the sum of the series obtained earlier by Lavoie et al. [2]. Some new and known results are also deduced as applications of our main formulas. 展开更多
关键词 Transformation Formulas lauricella’s function Dixon’s Theorem Kampé de Fériet function
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Evaluation of Generalized Error Function via Fast-Converging Power Series
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作者 Serdar Beji 《Advances in Pure Mathematics》 2024年第6期495-514,共20页
A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power... A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power series expansion developed in resolving the so-called Grandi’s paradox. Comparisons with accurate tabulated values for well-known cases such as the error function are presented using the expansions truncated at various orders. 展开更多
关键词 Generalized Error function Gamma function Grandi’s Paradox Fast-Converging Power series
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Existence of Monotone Positive Solution for a Fourth-Order Three-Point BVP with Sign-Changing Green’s Function
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作者 Junrui Yue Yun Zhang Qingyue Bai 《Open Journal of Applied Sciences》 2024年第1期63-69,共7页
This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones a... This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones and iterative technique. 展开更多
关键词 Fourth-Order Three-Point Boundary Value Problem sign-Changing Green’s function Fixed Point Index Iterative Technique Monotone Positive solution EXIsTENCE
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A Set of Almost Automorphic Functions and Applications
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作者 William Dimbour Vincent Valmorin 《Applied Mathematics》 2024年第1期9-21,共13页
For a set S of real numbers, we introduce the concept of S-almost automorphic functions valued in a Banach space. It generalizes in particular the space of Z-almost automorphic functions. Considering the space of S-al... For a set S of real numbers, we introduce the concept of S-almost automorphic functions valued in a Banach space. It generalizes in particular the space of Z-almost automorphic functions. Considering the space of S-almost automorphic functions, we give sufficient conditions of the existence and uniqueness of almost automorphic solutions of a differential equation with a piecewise constant argument of generalized type. This is done using the Banach fixed point theorem. 展开更多
关键词 Almost Automorphic functions s-Almost Automorphic functions Differential Equation with Piecewise Constant Argument of Generalized Type
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高压管汇材料疲劳性能测试及P-S-N模型曲线的拟合
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作者 黄艳娟 周思柱 李宁 《长江大学学报(自然科学版)》 2024年第3期55-61,共7页
高压管汇作为压裂设备中的主要易损件之一,其失效危害较大。它的失效原因主要是疲劳、冲蚀、腐蚀或者材料缺陷引起的刺漏和爆裂,其中尤以疲劳失效最不可预估。目前,对于高压管汇材料的疲劳性能研究不够深入,为解决高压管汇材料疲劳寿命... 高压管汇作为压裂设备中的主要易损件之一,其失效危害较大。它的失效原因主要是疲劳、冲蚀、腐蚀或者材料缺陷引起的刺漏和爆裂,其中尤以疲劳失效最不可预估。目前,对于高压管汇材料的疲劳性能研究不够深入,为解决高压管汇材料疲劳寿命的准确描述问题,以某国产高压管汇材料为例,进行了一系列疲劳试验,并基于试验数据,采用多种分布模型和不同S-N模型进行拟合分析,得出综合评价拟合能力最强的P-S-N模型。结果表明,该材料在中长疲劳寿命区,Weibull三参数模型在7级应力水平下综合评价能力最好;在存活率分别为50%、90%、99%、99.9%时,指数S-N模型的拟合系数均大于0.98,拟合能力最好。得出的P-S-N模型曲线可以为高压管汇的疲劳寿命以及安全设计提供依据。 展开更多
关键词 高压管汇材料 正态分布模型 Weibull分布模型 P-s-N模型 幂函数s-N模型 指数s-N模型
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基于哨兵函数和S变换的风力机叶片材料损伤特性研究
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作者 廖力达 舒王咏 +3 位作者 张芝铭 刘亮 冯飞 陈为强 《太阳能学报》 EI CAS CSCD 北大核心 2024年第7期656-663,共8页
利用声发射检测技术研究玻璃纤维增强环氧树脂复合材料的损伤特性,在此过程中,采用哨兵函数来表征该材料的损伤程度,并通过S变换和模糊C均值(FCM)聚类来分析声发射信号,从而获得材料的损伤特征。三点弯曲实验结束后对试件断口进行扫描... 利用声发射检测技术研究玻璃纤维增强环氧树脂复合材料的损伤特性,在此过程中,采用哨兵函数来表征该材料的损伤程度,并通过S变换和模糊C均值(FCM)聚类来分析声发射信号,从而获得材料的损伤特征。三点弯曲实验结束后对试件断口进行扫描电子显微镜(SEM)拍照来验证,可得:通过对SEM照片的分析得到基体开裂、纤维脱粘、分层破坏、纤维断裂4种损伤模式;对整个声发射事件进行哨兵函数分析,观察到试件在弯曲过程中哨兵函数曲线呈明显下降趋势;对依据哨兵函数划分的不同阶段的信号进行VMD降噪处理,然后采用S变换进行时频分析得到不同损伤的特征频率,最后采用FCM聚类进行验证。结果表明:哨兵函数值的突变可作为材料断裂的预警信号,材料损伤类型的识别可依据S变换的频率分布结果进行确定。 展开更多
关键词 风力机叶片 复合材料 声发射 损伤特性 哨兵函数 s变换
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Continuum Skyrme Hartree-Fock-Bogoliubov theory with Green’s function method for neutron-rich Ca,Ni,Zr,and Sn isotopes 被引量:1
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作者 En-Bo Huo Ke-Ran Li +2 位作者 Xiao-Ying Qu Ying Zhang Ting-Ting Sun 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第7期162-178,共17页
The possible exotic nuclear properties in the neutron-rich Ca,Ni,Zr,and Sn isotopes are examined with the continuum Skyrme Hartree-Fock-Bogoliubov theory in the framework of the Green’s function method.The pairing co... The possible exotic nuclear properties in the neutron-rich Ca,Ni,Zr,and Sn isotopes are examined with the continuum Skyrme Hartree-Fock-Bogoliubov theory in the framework of the Green’s function method.The pairing correlation,the couplings with the continuum,and the blocking effects for the unpaired nucleon in odd-A nuclei are properly treated.The Skyrme interaction SLy4 is adopted for the ph channel and the density-dependentinteraction is adopted for the pp chan-nel,which well reproduce the experimental two-neutron separation energies S_(2n)and one-neutron separation energies Sn.It is found that the criterion S_(n)>0 predicts a neutron drip line with neutron numbers much smaller than those for S_(2n)>0.Owing to the unpaired odd neutron,the neutron pairing energies−E_(pair)in odd-A nuclei are much lower than those in the neighbor-ing even-even nuclei.By investigating the single-particle structures,the possible halo structures in the neutron-rich Ca,Ni,and Sn isotopes are predicted,where sharp increases in the root-mean-square(rms)radii with significant deviations from the traditional rA^(1∕3)rule and diffuse spatial density distributions are observed.Analyzing the contributions of various partial waves to the total neutron densityρlj(r)∕ρ(r)reveals that the orbitals located around the Fermi surface-particularly those with small angular momenta-significantly affect the extended nuclear density and large rms radii.The number of neutrons Nλ(N_(0))occupying above the Fermi surfacen(continuum threshold)is discussed,whose evolution as a function of the mass number A in each isotope is consistent with that of the pairing energy,supporting the key role of the pairing correlation in halo phenomena. 展开更多
关键词 Neutron-rich nuclei Neutron halo skyrme Hartree-Fock-Bogoliubov theory Green’s function method
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GREEN'S FUNCTION AND THE POINTWISE BEHAVIORS OF THE VLASOV-POISSON-FOKKER-PLANCK SYSTEM
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作者 钟明溁 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期205-236,共32页
The pointwise space-time behaviors of the Green’s function and the global solution to the Vlasov-Poisson-Fokker-Planck(VPFP)system in three dimensional space are studied in this paper.It is shown that the Green’s fu... The pointwise space-time behaviors of the Green’s function and the global solution to the Vlasov-Poisson-Fokker-Planck(VPFP)system in three dimensional space are studied in this paper.It is shown that the Green’s function consists of the diffusion waves decaying exponentially in time but algebraically in space,and the singular kinetic waves which become smooth for all(t,x,v)when t>0.Furthermore,we establish the pointwise space-time behaviors of the global solution to the nonlinear VPFP system when the initial data is not necessarily smooth in terms of the Green’s function. 展开更多
关键词 Vlasov-Poisson-Fokker-Planck system Green’s function pointwise behavior spectrum structure
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Quantifyingα-diversity as a continuous function of location——a case study of a temperate forest
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作者 Peijian Shi Brady K.Quinn +2 位作者 Long Chen Jie Gao Julian Schrader 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第6期1683-1691,共9页
α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or pl... α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or plot).Although such indices provide overall diversity estimates that can be analyzed,their values are not spatially continuous nor applicable in theory to any point within the study region,and thus they cannot be treated as spatial covariates for analyses of other variables.Herein,we extended the Simpson’s and Shannon-Wiener indices to create point estimates ofα-diversity for any location based on spatially explicit species occurrences within different bandwidths(i.e.,radii,with the location of interest as the center).For an arbitrary point in the study region,species occurrences within the circle plotting the bandwidth were weighted according to their distance from the center using a tri-cube kernel function,with occurrences closer to the center having greater weight than more distant ones.These novel kernel-basedα-diversity indices were tested using a tree dataset from a 400 m×400 m study region comprising a 200 m×200 m core region surrounded by a 100-m width buffer zone.Our newly extendedα-diversity indices did not disagree qualitatively with the traditional indices,and the former were slightly lower than the latter by<2%at medium and large band widths.The present work demonstrates the feasibility of using kernel-basedα-diversity indices to estimate diversity at any location in the study region and allows them to be used as quantifiable spatial covariates or predictors for other dependent variables of interest in future ecological studies.Spatially continuousα-diversity indices are useful to compare and monitor species trends in space and time,which is valuable for conservation practitioners. 展开更多
关键词 Distance-based weighting Diversity continuum Kernel function shannon-Wiener index simpson’s index Tri-cube kernel
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Green's functions of two-dimensional piezoelectric quasicrystal in half-space and bimaterials
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作者 Xiaoyu FU Xiang MU +2 位作者 Jinming ZHANG Liangliang ZHANG Yang GAO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第2期237-254,共18页
In this paper,we obtain Green’s functions of two-dimensional(2D)piezoelectric quasicrystal(PQC)in half-space and bimaterials.Based on the elastic theory of QCs,the Stroh formalism is used to derive the general soluti... In this paper,we obtain Green’s functions of two-dimensional(2D)piezoelectric quasicrystal(PQC)in half-space and bimaterials.Based on the elastic theory of QCs,the Stroh formalism is used to derive the general solutions of displacements and stresses.Then,we obtain the analytical solutions of half-space and bimaterial Green’s functions.Besides,the interfacial Green’s function for bimaterials is also obtained in the analytical form.Before numerical studies,a comparative study is carried out to validate the present solutions.Typical numerical examples are performed to investigate the effects of multi-physics loadings such as the line force,the line dislocation,the line charge,and the phason line force.As a result,the coupling effect among the phonon field,the phason field,and the electric field is prominent,and the butterfly-shaped contours are characteristic in 2D PQCs.In addition,the changes of material parameters cause variations in physical quantities to a certain degree. 展开更多
关键词 Green’s function two-dimensional(2D)piezoelectric quasicrystal(PQC) stroh formalism HALF-sPACE BIMATERIAL
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Long-term radiofrequency electromagnetic fields exposure attenuates cognitive dysfunction in 5×FAD mice by regulating microglial function
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作者 Yeonghoon Son Hye-Jin Park +3 位作者 Ye Ji Jeong Hyung-Do Choi Nam Kim Hae-June Lee 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第11期2497-2503,共7页
We have previously found that long-term effects of exposure to radiofrequency electromagnetic fields in 5xFAD mice with severe late-stage Alzheimer’s disease reduced both amyloid-βdeposition and glial activation,inc... We have previously found that long-term effects of exposure to radiofrequency electromagnetic fields in 5xFAD mice with severe late-stage Alzheimer’s disease reduced both amyloid-βdeposition and glial activation,including microglia.To examine whether this therapeutic effect is due to the regulation of activated microglia,we analyzed mic roglial gene expression profiles and the existence of microglia in the brain in this study.5xFAD mice at the age of 1.5 months were assigned to sham-and radiofrequency electromagnetic fields-exposed groups and then animals were exposed to 1950 MHz radiofrequency electromagnetic fields at a specific absorption rate of 5 W/kg for 2 hours/day and 5 days/week for 6 months.We conducted behavioral tests including the object recognition and Y-maze tests and molecular and histopathological analysis of amyloid precursor protein/a myloid-beta metabolism in brain tissue.We confirmed that radiofrequency electromagnetic field exposure for 6 months ameliorated cognitive impairment and amyloid-βdeposition.The expression levels of Iba1(pan-microglial marker)and colony-stimulating factor 1 receptor(CSF1R;regulates microglial prolife ration)in the hippocampus in 5xFAD mice treated with radiofrequency electromagnetic fields were significantly reduced compared with those of the sham-exposed group.Subsequently,we analyzed the expression levels of genes related to mic rogliosis and microglial function in the radiofrequency electromagnetic fields-exposed group compared to those of a CSF1R inhibitor(PLX3397)-treated group.Both radiofrequency electromagnetic fields and PLX3397 suppressed the levels of genes related to microgliosis(Csf1r,CD68,and Ccl6)and pro-inflammatory cytokine interleukin-1β.N otably,the expression levels of genes related to mic roglial function,including Trem2,Fcgr1α,Ctss,and Spi1,were decreased after long-term radiofrequency electromagnetic field exposure,which was also observed in response to microglial suppression by PLX3397.These results showed that radiofrequency electromagnetic fields ameliorated amyloid-βpathology and cognitive impairment by suppressing amyloid-βdeposition-induced microgliosis and their key regulator,CSF1R. 展开更多
关键词 5×FAD Alzheimer’s disease CsF1R long term exposure microglial function NEUROINFLAMMATION radiofrequency electromagnetic fields therapeutic effect
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基于S函数的调节阀粘滞特性检测方法
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作者 李世伟 尚群立 《高技术通讯》 CAS 北大核心 2024年第4期406-412,共7页
调节阀粘滞特性引起的振荡是工业控制回路性能恶化的最常见来源。目前虽然已有许多检测调节阀粘滞特性的方法,但这些方法的复杂性或存在的缺陷限制着其在实际工况中的具体应用。本文提出了一种检测过程控制回路中调节阀粘滞故障的新方... 调节阀粘滞特性引起的振荡是工业控制回路性能恶化的最常见来源。目前虽然已有许多检测调节阀粘滞特性的方法,但这些方法的复杂性或存在的缺陷限制着其在实际工况中的具体应用。本文提出了一种检测过程控制回路中调节阀粘滞故障的新方法。该方法将控制器输出(OP)和过程变量(PV)的变化(ΔPV)在相平面图中所构成变化趋势与标准S函数进行对比,根据实际函数趋势与标准S函数间的差异计算相关系数,通过相关系数的数值具体得出调节阀中是否存在粘滞特性。仿真实例和实际工业数据分析实验验证了提出方法的有效性。 展开更多
关键词 调节阀 相关系数 s函数 粘滞检测
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H_(2)S、HCN、PH_(3)在FeO(100)表面吸附的密度泛函理论研究
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作者 杨蒙 彭国建 +4 位作者 刘永军 张艳琨 杨春晓 夏福婷 张秋林 《原子与分子物理学报》 CAS 北大核心 2024年第1期29-36,共8页
基于密度泛函理论研究了H_(2)S、HCN、PH_(3)在FeO(100)表面的吸附行为,其吸附位点主要考虑四个:Fe-top(铁顶位)、O-top(氧顶位)、Hollow(空位)、Bridge(桥位).结果表明H_(2)S吸附在O-top吸附位点的吸附能最小,为-1.02 eV,即在该位点的... 基于密度泛函理论研究了H_(2)S、HCN、PH_(3)在FeO(100)表面的吸附行为,其吸附位点主要考虑四个:Fe-top(铁顶位)、O-top(氧顶位)、Hollow(空位)、Bridge(桥位).结果表明H_(2)S吸附在O-top吸附位点的吸附能最小,为-1.02 eV,即在该位点的吸附体系最稳定.当HCN吸附在FeO(100)表面时,各吸附位点的稳定顺序为Hollow>Fe-top>Bridge>O-top.PH_(3)的最稳定的吸附位点与H_(2)S的一致,为O-top吸附位点,其吸附能为-1.11 eV.当H_(2)S吸附在O-top吸附位点时,H_(2)S与FeO(100)表面的电荷转移量最多,说明该吸附构型最稳定,而HCN吸附在FeO(100)表面,在Hollow吸附位点的电荷转移量最多,也即该吸附位点属于最稳定吸附位点.PH_(3)与FeO(100)表面之间的电荷转移量最多的吸附位点与H_(2)S的相同.当H_(2)S和PH_(3)吸附在O-top吸附位点时,吸附后的态密度曲线整体向低能级移动,峰值降低,其吸附结构变得更加稳定.而HCN吸附在Hollow位点时,吸附后的HCN态密度曲线向能量更低的区域移动,吸附体系变得更稳定. 展开更多
关键词 密度泛函理论 H_(2)s HCN PH_(3) 吸附能
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Rotating magnetic field inhibits Aβ protein aggregation and alleviates cognitive impairment in Alzheimer’s disease mice
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作者 Ruo-Wen Guo Wen-Jing Xie +5 位作者 Biao Yu Chao Song Xin-Miao Ji Xin-Yu Wang Mei Zhang Xin Zhang 《Zoological Research》 SCIE CSCD 2024年第4期924-936,共13页
Amyloid beta(Aβ)monomers aggregate to form fibrils and amyloid plaques,which are critical mechanisms in the pathogenesis of Alzheimer’s disease(AD).Given the important role of Aβ1-42 aggregation in plaque formation... Amyloid beta(Aβ)monomers aggregate to form fibrils and amyloid plaques,which are critical mechanisms in the pathogenesis of Alzheimer’s disease(AD).Given the important role of Aβ1-42 aggregation in plaque formation,leading to brain lesions and cognitive impairment,numerous studies have aimed to reduce Aβaggregation and slow AD progression.The diphenylalanine(FF)sequence is critical for amyloid aggregation,and magnetic fields can affect peptide alignment due to the diamagnetic anisotropy of aromatic rings.In this study,we examined the effects of a moderate-intensity rotating magnetic field(RMF)on Aβaggregation and AD pathogenesis.Results indicated that the RMF directly inhibited Aβamyloid fibril formation and reduced Aβ-induced cytotoxicity in neural cells in vitro.Using the AD mouse model APP/PS1,RMF restored motor abilities to healthy control levels and significantly alleviated cognitive impairments,including exploration and spatial and non-spatial memory abilities.Tissue examinations demonstrated that RMF reduced amyloid plaque accumulation,attenuated microglial activation,and reduced oxidative stress in the APP/PS1 mouse brain.These findings suggest that RMF holds considerable potential as a non-invasive,high-penetration physical approach for AD treatment. 展开更多
关键词 lzheimer’s disease Rotating magnetic field Amyloid-β Cognitive function Alzheimer’s disease animal models
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Neuroprotective effect of liraglutide and memantine in a rat model of Alzheimer’s disease
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作者 Duaa M.Bakhshwin Foziya W.Alhalabi +7 位作者 Mohamad Omar Barasheed Ahmed M.Bakhshwin Maha H.Jamal Mohammed A.Bazuhair Fatemah O.Kamel Rania M.Magadmi Zoheir A Damanhouri Samar M.Alsaggaf 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2024年第5期207-214,共8页
Objective:To assess the effect of memantine combined with liraglutide on aluminum chloride(AlCl_(3))and D-galactose(D-GAL)-induced neurotoxicity in rats.Methods:Male Wistar rats were divided into 5 groups of 5 animals... Objective:To assess the effect of memantine combined with liraglutide on aluminum chloride(AlCl_(3))and D-galactose(D-GAL)-induced neurotoxicity in rats.Methods:Male Wistar rats were divided into 5 groups of 5 animals each:the positive control,the negative control,the memantine-treated group,the liraglutide-treated group,and the combination group treated with memantine and liraglutide.AlCl_(3)and D-GAL were used to induce neurotoxicity.Behavioral tests,brain beta-amyloid protein,and oxidative stress biomarkers were evaluated.Results:The Morris water maze test indicated an enhanced memory in the combination group.Moreover,the combination treatment of liraglutide and memantine resulted in a remarkable reduction in the beta-amyloid protein level in the brain tissue.Neuronal inflammation and oxidative stress biomarkers were significantly reduced,and the levels of antioxidant parameters were enhanced.Conclusions:The combination of liraglutide and memantine exerts neuroprotective effects and enhances memory and cognitive functions in rats with Alzheimer’s disease. 展开更多
关键词 Alzheimer’s disease Cognitive function Glucagonlike peptide-1 LIRAGLUTIDE MEMANTINE
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6-巯基-5-三唑并[4,3-b]-s-四嗪(MTT)的密度泛函理论研究
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作者 赵宁 陈慧 +2 位作者 任黎英 邵长斌 陈玉锋 《原子与分子物理学报》 CAS 北大核心 2024年第1期37-42,共6页
采用密度泛函理论(Density functional theory,DFT),在B3LYP/6-31g(d)(C,H,N,S),Ag原子采用LanL2d赝势基组水平上对甲醛(HCHO)与4-氨基-5肼基-3-巯基-1,2,4-三唑(4-amino-5-hydrazino-3-mercapto-1,2,4-triazole,AHMT)衍生化反应生的成... 采用密度泛函理论(Density functional theory,DFT),在B3LYP/6-31g(d)(C,H,N,S),Ag原子采用LanL2d赝势基组水平上对甲醛(HCHO)与4-氨基-5肼基-3-巯基-1,2,4-三唑(4-amino-5-hydrazino-3-mercapto-1,2,4-triazole,AHMT)衍生化反应生的成产物6-巯基-5-三唑并[4,3-b]-s-四嗪(6-mercapto-5-triazolo[4,3-b]-s-tetrazine,MTT)及其银配合物进行结构优化,优化结果表明MTT的结构是一个近平面结构.通过对频率计算,获得MTT分子及其银配合物的拉曼光谱,对400-1800 cm^(-1)波段内的拉曼光谱特征峰进行了指认.同时讨论了MTT分子的表面静电势,分析可能发生化学反应的位点.并采用含时密度泛函理论(Time Dependent density functional theory,TDDFT)对MTT分子与Ag3配合物的激发态进行了计算分析,并使用电荷转移光谱对Ag配合物与MTT之间电荷转移关系进行了研究.该研究对MTT分子的光谱测定和电子性质提供了理论基础. 展开更多
关键词 密度泛函理论 拉曼光谱 紫外光谱 6-巯基-5-三唑并[4 3-b]-s-四嗪
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The Bivariate Normal Integral via Owen’s T Function as a Modified Euler’s Arctangent Series
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作者 Janez Komelj 《American Journal of Computational Mathematics》 2023年第4期476-504,共29页
The Owen’s T function is presented in four new ways, one of them as a series similar to the Euler’s arctangent series divided by 2&#960, which is its majorant series. All possibilities enable numerically stable ... The Owen’s T function is presented in four new ways, one of them as a series similar to the Euler’s arctangent series divided by 2&#960, which is its majorant series. All possibilities enable numerically stable and fast convergent computation of the bivariate normal integral with simple recursion. When tested  computation on a random sample of one million parameter triplets with uniformly distributed components and using double precision arithmetic, the maximum absolute error was 3.45 × 10<sup>-</sup><sup>16</sup>. In additional testing, focusing on cases with correlation coefficients close to one in absolute value, when the computation may be very sensitive to small rounding errors, the accuracy was retained. In rare potentially critical cases, a simple adjustment to the computation procedure was performed—one potentially critical computation was replaced with two equivalent non-critical ones. All new series are suitable for vector and high-precision computation, assuming they are supplemented with appropriate efficient and accurate computation of the arctangent and standard normal cumulative distribution functions. They are implemented by the R package Phi2rho, available on CRAN. Its functions allow vector arguments and are ready to work with the Rmpfr package, which enables the use of arbitrary precision instead of double precision numbers. A special test with up to 1024-bit precision computation is also presented. 展开更多
关键词 Owen’s T function Bivariate Normal Integral Euler’s Arctangent series RECURsION R Package Phi2rho
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Distinct gut microbiomes in Thai patients with colorectal polyps
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作者 Thoranin Intarajak Ahmad Nuruddin Khoiri +5 位作者 Kanthida Kusonmano Weerayuth Kittichotirat Sawannee Sutheeworapong Supapon Cheevadhanarak Wandee Udomchaiprasertkul Chinae Thammarongtham 《World Journal of Gastroenterology》 SCIE CAS 2024年第27期3336-3355,共20页
BACKGROUND Colorectal polyps that develop via the conventional adenoma-carcinoma sequence[e.g.,tubular adenoma(TA)]often progress to malignancy and are closely associated with changes in the composition of the gut mic... BACKGROUND Colorectal polyps that develop via the conventional adenoma-carcinoma sequence[e.g.,tubular adenoma(TA)]often progress to malignancy and are closely associated with changes in the composition of the gut microbiome.There is limited research concerning the microbial functions and gut microbiomes associated with colorectal polyps that arise through the serrated polyp pathway,such as hyperplastic polyps(HP).Exploration of microbiome alterations asso-ciated with HP and TA would improve the understanding of mechanisms by which specific microbes and their metabolic pathways contribute to colorectal carcinogenesis.AIM To investigate gut microbiome signatures,microbial associations,and microbial functions in HP and TA patients.METHODS Full-length 16S rRNA sequencing was used to characterize the gut microbiome in stool samples from control participants without polyps[control group(CT),n=40],patients with HP(n=52),and patients with TA(n=60).Significant differences in gut microbiome composition and functional mechanisms were identified between the CT group and patients with HP or TA.Analytical techniques in this study included differential abundance analysis,co-occurrence network analysis,and differential pathway analysis.RESULTS Colorectal cancer(CRC)-associated bacteria,including Streptococcus gallolyticus(S.gallolyticus),Bacteroides fragilis,and Clostridium symbiosum,were identified as characteristic microbial species in TA patients.Mediterraneibacter gnavus,associated with dysbiosis and gastrointestinal diseases,was significantly differentially abundant in the HP and TA groups.Functional pathway analysis revealed that HP patients exhibited enrichment in the sulfur oxidation pathway exclusively,whereas TA patients showed dominance in pathways related to secondary metabolite biosynthesis(e.g.,mevalonate);S.gallolyticus was a major contributor.Co-occurrence network and dynamic network analyses revealed co-occurrence of dysbiosis-associated bacteria in HP patients,whereas TA patients exhibited co-occurrence of CRC-associated bacteria.Furthermore,the co-occurrence of SCFA-producing bacteria was lower in TA patients than HP patients.CONCLUSION This study revealed distinct gut microbiome signatures associated with pathways of colorectal polyp development,providing insights concerning the roles of microbial species,functional pathways,and microbial interactions in colorectal carcinogenesis. 展开更多
关键词 Gut microbiome Colorectal adenoma Hyperplastic polyp Full-length 16s rRNA Microbial correlation networks Predicted functional mechanisms
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Multisensory mechanisms of gait and balance in Parkinson’s disease:an integrative review
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作者 Stiven Roytman Rebecca Paalanen +4 位作者 Giulia Carli Uros Marusic Prabesh Kanel Teus van Laar Nico I.Bohnen 《Neural Regeneration Research》 SCIE CAS 2025年第1期82-92,共11页
Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have ... Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population.Posture and gait control does not happen automatically,as previously believed,but rather requires continuous involvement of central nervous mechanisms.To effectively exert control over the body,the brain must integrate multiple streams of sensory information,including visual,vestibular,and somatosensory signals.The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work.Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults.Insufficient emphasis,however,has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance.In the present work,we review the contributions of somatosensory,visual,and vestibular modalities,along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s disease.We also review evidence of vestibular contributions to multisensory temporal binding windows,previously shown to be highly pertinent to fall risk in older adults.Lastly,we relate multisensory vestibular mechanisms to potential neural substrates,both at the level of neurobiology(concerning positron emission tomography imaging)and at the level of electrophysiology(concerning electroencephalography).We hope that this integrative review,drawing influence across multiple subdisciplines of neuroscience,paves the way for novel research directions and therapeutic neuromodulatory approaches,to improve the lives of older adults and patients with neurodegenerative diseases. 展开更多
关键词 aging BALANCE encephalography functional magnetic resonance imaging GAIT multisensory integration Parkinson’s disease positron emission tomography sOMATOsENsORY VEsTIBULAR visual
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