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Carbohydrates mediate sperm-ovum adhesion and triggering of the acrosome reaction

Asian Journal of Andrology 2000年第2期2卷 87-97页

作者： Daulat R.p Thlsiani Department of Obstetrics & Gynecology and Cell Biology Vanderbilt University School of Medicine Room D-3243 MCN Nashville Tennessee 37232-2633 USA

The fertilization process is the net result of a complex sequence of events that collectively result in the fusion of theopposite gametes. The male gamete undergoes continuous morphological and biochemical modifications during spermdevelopment in the testis (spermatogenesis), maturation in the epididymis, and capacitation in the female reproductivetract. Only the capacitated spermatozoa are able to recognize and bind to the bioactive glycan residue(s) on the ovum'sextracellular coat, the zona pellucida (Zp). Sperm-zona binding in the mouse and several other species is believed totake place in two stages. First, capacitated (acrosome-intact) spermatozoa loosely and reversibly adhere to the zona-in-tact ovum. In the second stage tight irreversible binding occurs. Both types of bindings are attributed to the presence ofglycan- binding proteins (receptors) on the sperm plasma membrane and their complementary bioactive glycan units(ligands) on the surface of the Zp. The carbohydrate-mediated adhesion event initiates a signal transduction cascade re-sulting in the exocytosis of acrosomal contents. This step is believed to be prerequisite which allows the hyperactivatedacrosome-reacted spermatozoa to penetrate the Zp and fertilize the ovum. This review focuses on the role of carbohy-drate residues in sperm-ovum interaction, and triggering of the acrosome reaction. I have attempted to discuss extensiveprogress that has been made to enhance our understanding of the well programmed multiple molecular events necessaryfor successful fertilization. This review will identify these events, and discuss the functional significance of carbohy-drates in these events.

关键词： sperm capacitation sperm-ovum interaction acrosome reaction carbohydrates fertilization

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Tests to measure the quality of spermatozoa at spermiation

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Asian Journal of Andrology 2010年第1期12卷 71-78页

作者： Rupert p. Amann Animal Reproduction and Biotechnology Laboratory Colorado State University Ft Collins CO 80526-1683 USA

This commentary is to critique the revised World Health Organization （WHO） semen analysis manual as it pertains to characteristics of a spermatozoon at spermiation. The aims of the revised WHO manual include improving the ＇quality of semen analysis＇ without any restriction to clinical use. Furthermore, the manual states that semen analysis may be useful for （a）＇investigating male fertility status＇ and （b）＇monitoring spermatogenesis during and following male fertility regula- tion.＇ However, if the analysis of ejaculated spermatozoa is intended for the purposes described in （b）, then cells that are abnormal at spermiation must be identified. This paper takes the position that the manual does not identify methods to estimate the quality of spermatozoa at spermiation. Instead, it uses a ＇gold standard＇ of sperm passing through the cervical mucus or arriving near the site of fertilization. Although this standard is appropriate for drawing conclusions regarding the probability that an individual could impregnate his partner, it is not appropriate for studying illness of the testes per se. Herein, the measures of sperm quality presented in the WHO manual are critiqued with respect to the detection of spermatozoa that were abnormal at spermiation vs. those that became abnormal subsequently. Quality assessments based on the percentage of motile or ＇viable＇ spermatozoa are meaningless. Alternative quality attributes defining spermatozoa at spermiation are presented in this paper. In conclusion, assessment of spermatozoal quality at spermiation, on the basis of quality attributes of individual ejaculated spermatozoa, is best achieved through application of （a） a new paradigm for the morphological evaluation of sperm quality and （b） modern analytical techniques to evaluate, in an adequate sample, several appropriate independent attributes in each spermatozoon in order to more accurately identify the proportion of abnormal spermatozoa.

关键词： attributes of spermatozoa purpose of semen examination semen analysis sperm quality spermiation

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Numerical Solution for the Extrapolation problem of Analytic Functions

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Research 2019年第1期2019卷 936-945页

作者： Nikolaos p.Bakas Intelligent Systems Lab&Civil Engineering Department School of ArchitectureEngineeringLand and Environmental SciencesNeapolis University Pafos2 Danais Avenue8042 PaphosCyprus

In this work,a numerical solution for the extrapolation problem of a discrete set of n values of an unknown analytic function is *** proposed method is based on a novel numerical scheme for the rapid calculation of higher order derivatives,exhibiting high accuracy,with error magnitude of O(10^(−100))or less.A variety of integrated radial basis functions are utilized for the solution,as well as variable precision arithmetic for the *** alterations in the function’s direction,with no curvature or periodicity information specifed,are efciently ***,the proposed procedure can be extended in multiple *** attained extrapolation spans are greater than two times the given domain *** signifcance of the approximation errors is comprehensively analyzed and reported,for 5832 test cases.

关键词： extrapolation curvature function

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Symmetries of the interacting boson model

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Frontiers of physics 2018年第6期13卷 79-88页

作者： p. Van Isacker Grand Accelerateur National d'Ions Lourds CEA//DRF CNRS//IN2P3 Bd Henri Becquerel BP 55027 F-14076 Caen France

This contribution reviews the symmetry properties of the interacting boson model of Arima and Iachello. While the concept of a dynamical symmetry is by now a familiar one, this is not necessarily so for the extended notions of partial dynamical symmetry and quasi dynamical symmetry, which can be beautifully illustrated in the context of the interacting boson model. The main conclusion of the analysis is that dynamical symmetries are scarce while their partial and quasi extensions are ubiquitous.

关键词： interacting boson model

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A synsedimentary structure formation model for the Far East Jurassic-Early Cretaceous basins and uplifts, Russia

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Science China Earth Sciences 2009年第12期52卷 1979-1992页

作者： UTKIN Valentine p. Far East Geological Institute Far East Branch Russian Academy of Sciences Vladivostok 690022 Russia

This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive mapping materials and special structural field studies. It has been found that sedimentary basins developed as rift-grabens were synchronous with formation of horsts separating the basins. The imbricated-thrust structures, which are morphologically similar to the subduction-related accretionary prisms but nevertheless different in nature, were formed within the transition zone between the uplifted structures and basins. A synsedimentary supply of a mantle-derived material into basins points to a temporarily continual extension of continental lithosphere. The lithospheric plates moved apart during the strike slip faulting with the subsequent involvement of convective mantle flows and plume diapirism (continental spreading?). Because of horizontal movement of lithospheric plates, horstlike uplifts were formed in the frontal zones. In sedimentary formations overlapping the lithospheric plates, the synsedimentary imbricated-thrust structures were developed, favouring a growth of the uplifts in lateral direction toward the axial zones of rift-grabens. Synchronously with basaltic volcanic activity in the rift-graben zones, basic-ultrabasic intrusive magmatism occurred within the limits of the contiguous uplifts.

关键词： geodynamics strike-slip fault rift-graben sedimentary basin horst-accretionary system

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A Generalized Cubic Functional Equation

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Acta Mathematica Sinica,English Series 2005年第5期21卷 1159-1166页

作者： p.K.SAHOO Department of Mathematics University of LouisvilleLouisvilleKentucky 40292USA

In this paper, we determine the general solution of the functional equation f1 （2x ＋ y）＋ f2（2x - y） = f3（x ＋ y）＋ f4（x - y）＋ f5（x） without assuming any regularity condition on the unknown functions f1,f2,f3, f4, f5 ： R→R. The general solution of this equation is obtained by finding the general solution of the functional equations f（2x ＋ y）＋ f（2x - y） = g（x ＋ y）＋ g（x - y）＋ h（x） and f（2x ＋ y） - f（2x - y） = g（x ＋ y） - g（x - y）. The method used for solving these functional equations is elementary but exploits an important result due to Hosszfi. The solution of this functional equation can also be determined in certain type of groups using two important results due to Szekelyhidi.

关键词： Additive function Cubic functional equation Difference operator Frechet functional equation Jensen functional equation n-additive function

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Torsion Completeness of Sylow p-Groups in Semisimple Group Rings

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Acta Mathematica Sinica,English Series 2004年第5期20卷 893-898页

作者： p.V.DANCHEV Mathematical Department Plovdiv State UniversityPlovdiv 4000Bulgaria Insurance Supervision DirectorateMinistry of FinanceSofia 1000Bulgaria

Let G be an abelian p-group and K be a field of the first kind with respect to p of charK p and of s_p(K)=N or N∪{0}.Then it is shown that the normed Sylow p-subgroup S(KG)is torsion complete if and only if G is bounded(Theorem 1).An analogous fact is proved for the case when K is of the second kind(Theorem 2).These completely settle a conjecture posed by us in ***. ***.(1993)and are also a supplement to our result in the modular case published in Acta ***.(1997).

关键词： Normalized p-units Fields of the first and of the second type Torsion complete primary components

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The Dirichlet Form of a Gradient-type Drift Transformation of a Symmetric Diffusion

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Acta Mathematica Sinica,English Series 2008年第7期24卷 1057-1066页

作者： p.J.FITZSIMMONS Department of Mathematics University of CaliforniaSan Diego9500 Gilman DriveLa JollaCA 92093-0112USA

In the context of a symmetric diffusion process X, we give a precise description of the Dirichlet form of the process obtained by subjecting X to a drift transformation of gradient type. This description relies on bou... 详细信息

关键词： diffusion Dirichlet form Girsanov theorem drift perturbation Markovian extension umqueness

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FRACTAL pORE DIFFUSION MODEL OF FLUIDS IN pOROUS MEDIA

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 877-882页

作者： Tao, D.p. Kunming Univ of Science and Technology Kunming China

A fractal pore diffusion model of fluids in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot's fractal length-area relation. Based on the model, a new formula and its interpretation about the tortuosity of pore structures of a porous medium have been suggested, from which the fractal pore diffusion resistance has been defined. The resistance ascends obviously with the fractal pore dimension and the conversion ratio increasing, especially in the middle-latter period of fluid-solid reactions.

关键词： Carbon dioxide Chemical reactions Coke Fractals Geometry Models porous materials

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potential physiological and pathological roles for axonal ryanodine receptors

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Neural Regeneration Research 2023年第4期18卷 756-759页

作者： David p.Stirling Kentucky Spinal Cord Injury Research Center and Departments of Neurological Surgery Anatomical Sciences and NeurobiologyMicrobiology and ImmunologyUniversity of LouisvilleSchool of MedicineLouisvilleKYUSA

Clinical disability following trauma or disease to the spinal cord often involves the loss of vital white matter elements including axons and *** excessive Cais an established driver of axonal degeneration,therapeutically targeting externally sourced Cato date has had limited success in both basic and clinical *** factors that may underlie this limited success include the complexity of the many potential sources of Caentry and the discovery that axons also contain substantial amounts of stored Cathat if inappropriately released could contribute to axonal *** Castorage is largely accomplished by the axoplasmic reticulum that is part of a continuous network of the endoplasmic reticulum that provides a major sink and source of intracellular Cafrom the tips of dendrites to axonal ***“neuron-within-a-neuron”is positioned to rapidly respond to diverse external and internal stimuli by amplifying cytosolic Calevels and generating short and long distance regenerative Cawaves through Cainduced *** review provides a glimpse into the molecular machinery that has been implicated in regulating ryanodine receptor mediated Carelease in axons and how dysregulation and/or overstimulation of these internodal axonal signaling nanocomplexes may directly contribute to Ca-dependent axonal *** ryanodine receptors expressed in dendrites,soma,and axonal terminals have been implicated in synaptic transmission and synaptic plasticity,but a physiological role for internodal localized ryanodine receptors remains largely *** physiological roles for internodal ryanodine receptors and such an elaborate internodal binary membrane signaling network in axons will also be discussed.

关键词： axomyelinic synapse axon axoplasmic reticulum calcium ryanodine receptor secondary axonal degeneration spinal cord injury voltage-gated calcium channel white matter injury

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