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The mechanism of sperm-egg interaction and the involvement of IZUMO1 in fusion

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Asian Journal of Andrology 2011年第1期13卷 81-87页

作者： Naokazu Inoue Masahito Ikawa masaru okabe Research Institute for Microbial Diseases Osaka University Yamadaoka 3-1 Suita Osaka 565-0871 Japan

An average human ejaculate contains over 100 million sperm, but only a few succeed in accomplishing the journey to an egg by migration through the female reproductive tract. Among these few sperm, only one participates in fertilization. There might be an ingenious molecular mechanism to ensure that the very best sperm fertilize an egg. However, recent gene disruption experiments in mice have revealed that many factors previously described as important for fertilization are largely dispensable. One could argue that the fertilization mechanism is made robust against gene disruptions. However, this is not likely, as there are already six different gene-disrupted mouse lines （Calmegin, Adam Ia, Adam2, Adam3, Ace and Pgapl）, all of which result in male sterility. The sperm from these animals are known to have defective zona-binding ability and at the same time lose oviduct-migrating ability. Concerning spermzona binding, the widely accepted involvement of sugar moiety on zona pellucida 3 （ZP3） is indicated to be dispensable by gene disruption experiments. Thus, the landscape of the mechanism of fertilization is revolving considerably. In the sperm-egg fusion process, CD9 on egg and IZUMO1 on sperm have emerged as essential factors. This review focuses on the mechanism of fertilization elucidated by gene-manipulated animals.

关键词： egg fusion gene-manipulation interaction IZUMO1 sperm zona pellucida

A novel cylindrical sandwich plate inspired by beetle elytra and its compressive properties

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Science China Technological Sciences 2024年第11期67卷 3465-3476页

作者： SONG YiHeng RUAN SiHan HAO Ning okabe YoJi School of Engineering The University of Tokyo School of Civil Engineering Southeast University School of Engineering RMIT University Institute of Industrial Science The University of Tokyo

The design and experimental analysis of a semi-cylindrical structure known as the cylindrical beetle elytron plate(CBEP) were presented. Radial compression tests and finite element simulation were performed on CBEPs under 30° and 45° inclined sliding support constraints, with a comparison made to cylindrical honeycomb plate(CHP). The study aims to investigate the superior compression performance and enhancement mechanisms of CBEPs. The results demonstrate that CBEPs exhibit a 14%–26% increase in specific load-bearing capacity and a 20% increase in specific energy absorption compared with CHPs with equal core wall thickness. Distinct “Z-shaped” tearing failures were observed, with honeycomb plates showing tearing at the center of the honeycomb walls, while beetle elytron plates exhibited tearing along the midline of the trabeculae. Three different stress patterns,including elastic-plastic development stage of arch, plastic hinge node stage, and rigid node stage, were identified and analyzed to explain the mechanical performance improvements and failure characteristics. Considering that structural damage to trabeculae mostly occurs at its junction with the skin, it is recommended to add chamfers to the junctions of CBEP. Therefore, this paper lays the groundwork for the engineering application of CBEP.

关键词： beetle elytron cylindrical beetle elytron plate compression performance failure characteristics enhancement mechanism

Exploring the effect of cooling rate on non-isothermal crystallization of copolymer polypropylene by fast scanning calorimetry

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China Foundry 2024年第4期21卷 379-386页

作者： Yang Liao Ye-yuan Hu Kosuke Ikeda Ryoji okabe Rui-fen Wu Ryota Ozaki Qing-yan Xu Key Laboratory for Advanced Materials Processing Technology School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Composite Laboratory Research&Innovation Center Mitsubishi Heavy Industries Ltd.Nagasaki 8510392Japan

Polypropylene is commonly used as a binder for ceramic injection molding,and rapid cooling is often encountered during ***,the crystallization behavior of polypropylene shows a strong dependence on cooling rate due to its semi-crystalline ***,the influence of cooling rate on the quality of final product cannot be *** this study,the fast differential scanning calorimetry(FSC)test was performed to study the influence of cooling rate on the non-isothermal crystallization behavior and non-isothermal crystallization kinetics of a copolymer polypropylene(PP BC03B).The results show that the crystallization temperatures and crystallinity decrease as the cooling rate *** addition,two exothermic peaks occur when cooling rate ranges from 30 to 300 K·s^(-1),indicating the formation of another crystal ***,Ozawa and Mo equations were used to explore the non-isothermal crystallization kinetics,and it can be concluded that the Mo method is suitable for this study.

关键词： cooling rate crystallization temperature crystallinity non-isothermal crystallization kinetics FSC copolymer polypropylene

EZH2 inhibitors promote β-like cell regeneration in young and adult type 1 diabetes donors

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Signal Transduction and Targeted Therapy 2024年第2期9卷 679-692页

作者： Keith Al-Hasani Safiya Naina Marikar Harikrishnan Kaipananickal Scott Maxwell Jun okabe Ishant Khurana Thomas Karagiannis Julia J.Liang Lina Mariana Thomas Loudovaris Thomas Kay Assam El-Osta Epigenetics in Human Health and Disease Program Baker Heart and Diabetes Institute75 Commercial RoadMelbourne 3004 VICAustralia Department of Diabetes Central Clinical SchoolMonash UniversityMelbourne 3004 VICAustralia Epigenetics in Human Health and Disease Laboratory Central Clinical SchoolMonash UniversityMelbourne 3004 VICAustralia School of Science STEM CollegeRMIT UniversityMelbourne 3001 VICAustralia Immunology and Diabetes Unit St Vincent’s Institute of Medical ResearchFitzroy 3065 VICAustralia Department of Medicine and Therapeutics The Chinese University of Hong KongSha TinHong Kong SAR Hong Kong Institute of Diabetes and Obesity Prince of Wales HospitalThe Chinese University of Hong Kong3/F Lui Che Woo Clinical Sciences Building30-32-Ngan Shing StreetSha TinHong Kong SAR Li Ka Shing Institute of Health Sciences The Chinese University of Hong KongSha TinHong Kong SAR Biomedical Laboratory Science Department of TechnologyFaculty of HealthUniversity College CopenhagenCopenhagenDenmark

β-cells are a type of endocrine cell found in pancreatic islets that synthesize,store and release *** type 1 diabetes(T1D),T-cells of the immune system selectively destroy the insulin-producingβ-*** of these cells leads to a lifelong dependence on exogenous insulin administration for ***,there is an urgent need to identify novel therapies that stimulateβ-cell growth and induceβ-cell *** and others have shown that pancreatic ductal progenitor cells are a promising source for regeneratingβ-cells for T1D owing to their inherent differentiation *** transcriptional suppression is refractory to exocrine reaction and tightly controls the regenerative potential by the EZH2 *** the present study,we show that transient stimulation of exocrine cells,derived from juvenile and adult T1D donors to the FDAapproved EZH2 inhibitors GSK126 and Tazemetostat(Taz)influence a phenotypic shift towards aβ-like cell *** transition from repressed to permissive chromatin states are dependent on bivalent H3K27me3 and H3K4me3 chromatin *** EZH2 is fundamental toβ-cell regenerative *** pancreatic ductal cells exhibit insulin production and secretion in response to a physiological glucose challenge ex *** pre-clinical studies underscore the potential of small molecule inhibitors as novel modulators of ductal progenitor differentiation and a promising new approach for the restoration ofβ-like cell function.

关键词： EZH2 struction inhibitors

Role and limitations of rehabilitation-induced neural network remodeling after stroke

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Neural Regeneration Research 2018年第12期13卷 2087-2088页

作者： Naohiko okabe Osamu Miyamoto Second Department of Physiology Kawasaki Medical School

There is plenty of evidence that proves the beneficial and reliable effects of rehabilitation therapy,making it the most common treatment for patients with chronic *** is believed that rehabilitation improves functional recovery through neural network remodeling,which is observed as a motor map reorganization or functional connectivity change assessed by intracortical microstimulation or functional magnetic resonance imaging（MRI）.

关键词： Role and limitations of rehabilitation-induced neural network remodeling after stroke

Axonal remodeling in the corticospinal tract after stroke： how does rehabilitative training modulate it？

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Neural Regeneration Research 2017年第2期12卷 185-192页

作者： Naohiko okabe Kazuhiko Narita Osamu Miyamoto Second Department of Physiology Kawasaki Medical School 577 Matsushima Kurashiki City Okayama Japan

Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals.

关键词： stroke rehabilitative training axonal remodeling corticospinal tract motor map reorganization motor system neurotrophic factor functional compensation neural activity growth promoting signal growth inhibitory signal task-specific training

Performance and Flow Condition of Small-Sized Axial Fan and Adoption of Contra-Rotating Rotors

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Journal of Thermal Science 2010年第1期19卷 1-6页

作者： T.Shigemitsu J.Fukutomi Y.okabe Institute of Technology and Science The University of Tokushima2-1 Minamijyosanjima-choTokushima 770-8506JAPAN Graduate School of Advanced Technology and Science The University of Tokushima2-1 Minamijyosanjima-choTokushima 770-8506JAPAN

Small-sized axial fans are used as air coolers for electric *** there is a strong demand for higher power of fans according to the increase of quantity of heat from electric ***,higher rotational speed design is conducted,although it causes the deterioration of the efficiency and the increase of *** the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of the *** the present paper,the performance and the internal flow condition of the small-sized axial fan are shown as a first step of the research for the contra-rotating small-sized axial fan and the important points to apply contra-rotating rotors to the small-sized axial fan are ***,the numerical flow analysis is conducted to investigate the performance of the contra-rotating small-sized axial fan and internal flow conditions and pressure distributions are clarified and the effect of contra-rotating rotors is considered.

关键词： Small-sized axial fan Contra-rotating rotors Numerical analysis Performance Internal flow

Beetle elytron plate and the synergistic mechanism of a trabecular-honeycomb core structure

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Science China(Technological Sciences) 2019年第1期62卷 87-93页

作者： CHEN JinXiang ZHANG XiaoMing okabe Yoji XIE Juan XU MengYe School of Civil Engineering Southeast University Department of Mechanical and Biofunctional Systems Institute of Industrial Science The University of Tokyo

For the development of lightweight biomimetic materials, the compressive properties of the beetle elytron plate(BEP, a type of biomimetic sandwich plate inspired from beetle elytra) and the underlying mechanism thereof were investigated. With the following results:(1) The shared mechanism of trabeculae was revealed by using structural analysis. It is further predicted that a BEP with hollow trabeculae should possess enhanced compressive properties.(2) When the trabecular number(N) in a hexagonal unit of the honeycomb is less than three, the compressive strength of the BEP is rapidly increased with the increment of N. When N is over four, the deformation capacity is significantly improved because of the arising of S-type buckling deformation in the core structure of the BEP. Furthermore, the definition of the BEP is proposed combined with the biological structure of the beetle elytra.(3) When N=6 and the external diameter of trabeculae is equal to the length of honeycomb walls, the synergistic mechanism between the trabeculae and the honeycomb walls in BEPs is fully exerted. Namely, the trabecula restricts the deformation of the honeycomb walls; in turn, the honeycomb walls provide lateral support for the trabecula. This mechanism leads the core in the BEP to generate an S-type global buckling deformation producing the best compressive properties. The results will greatly impact the biomimetic field of beetle elytra and many industries in which honeycomb structure also serves as a key component.

关键词： beetle elytra beetle elytron plate sandwich structure biomimetic material compressive property

On the Pressure Drop and the Velocity Distribution in the Cylindrical Vortex Chamber with Two Inlet Pipes for the Control of Vortex Flow

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Journal of Thermal Science 2005年第2期14卷 162-171页

作者： Akira OGAWA Tutomu OONO Hayato okabe Noriaki AKIBA Taketo OOYAGI 110-0011 Minowa-2-14-7 Taitou-kuTokyoJapanStudents of Nihon University until March of 2005 College of EngineeringDepartment Mechanical EngineeringStudents of Nihon University until March of 2005 College of EngineeringDepartment Mechanical EngineeringStudents of Nihon University until March of 2005 College of EngineeringDepartment Mechanical EngineeringStudents of Nihon University until March of 2005 College of EngineeringDepartment Mechanical Engineering

Vortex flow is applied to a cyclone dust collector, a vortex combustion chamber, and a vortex diode for vortex control. In order to apply the vortex flow to the industries, it is necessary to keep the stable flow condition and to estimate the response time of the transient flow process and also the intensity of the vortex flow. For control vortex flow, two types of vortex chamber with two inlet pipes were designed. One of them is to promote the vortex flow named as Co-Rotating Flow System and another one is to hinder the vortex flow named as Counter-Rotating Flow System. The pressure drops and the velocity distributions were measured for these vortex chambers. The estimation of the tangential velocity by the application of the angular momentum flux is compared with the measured velocity by a cylindrical Pitot-tube. The characteristics of the total pressure drop could be explained by introducing the circulation.

关键词： vortex chamber tangential velocity total and local pressure drops angular momentum flux circulation.