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Epidemiological and Clinical Aspects of Male Infertility in Patients Consulting at the Urology Department of the Yaounde Central Hospital

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Open Journal of Obstetrics and Gynecology 2024年第3期14卷 348-358页

作者： Achile Aurele Mbassi Florent Ymele Fouelifack Fatoumata Touda Dehukwe Maguira Roosvelt Dongmo Tiodjou Magloire Sida Biwole Department of Surgery and Specialties Higher Institute of Medical Technology of Nkolondom Yaounde Cameroon Department of Urology and Andrology Yaounde Central Hospital Yaounde Cameroon Gynecology and Obstetrics Unit Yaounde Central Hospital Yaounde Cameroon Associative Group for Research Education and Health La Falaise “GARES-Falaise” Dschang Cameroon Faculty of Medicine and Biomedical Sciences University of Yaounde I Yaounde Cameroon the higher institute of medical technology of nkolondom Yaounde Cameroon

Introduction: About 10 to 15% of couples in the world and 20 to 30% in Cameroon consult for infertility problems. Infertility is of male origin in 40% of cases. Our objective was to evaluate the epidemiological and clinical aspects of male infertility in our setting. Methods: This was a cross-sectional and descriptive study, with retrospective data collection from the files of patients received for male infertility, over 5 years and 6 months (from January 1st, 2016 to April 30th, 2021) at the Urology Department of the Yaounde Central Hospital. Phone calls were made to patients with incomplete records for completion following a verbal consent. Data reported on data collection forms were entered into a data entry form designed on CSPro software version 7.2. The database was later exported for descriptive statistics using the IBM SPSS software version 23. Qualitative variables were summarized in frequencies and percentages while quantitative variables were summarized in means with their standard deviations for normally distributed data, or medians and interquartile ranges otherwise. Results: Out of 110 patients whose records were analyzed, the median age was 37.0 years, with an interquartile range of 8.3, with 55.5% in the age group 30 to 39 years. Of these 95 (86.4%) were married, 58 (52.7%) were from the West region, 76 (69.1%) were employed. Past history was dominated by mumps 40 (36.4%), varicocele surgery 25 (22.7%), alcoholism 87 (79.1%) and smoking 15 (13.6%). A disorder of spermatogenesis was found in all our patients: 37 (33.6%) azoospermia, 27 (24.6%) asthenospermia and 26 (23.7%) oligospermia patients. Paraclinical evidence of chlamydia and gonococcal infections were found respectively in 38 (34.5%) and 14 (12.7%) patients, varicocele and testicular dystrophy respectively in 95 (86.4%) and 38 (34.5%) patients. Infertility was primary in 67 (60.9%) patients. Conclusion: Most patients with infertility were in their thirties, had risky social habits and comorbidities. An early start of

关键词： Epidemiology Clinical Male Infertility Central Hospital Yaounde

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Research fronts of agriculture in 2023

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Frontiers of Agricultural Science and Engineering 2024年第2期11卷 347-354页

作者： Jianxiang XU Yunzhou LI Jie ZHAO Liang SHI Yinkun YAO Jingyue TANG Science and technology Journal Center Higher Education Press FASE Editorial Office of institute for Science and technology Development China Agricultural University

At the end of 2023, Chinese Academy of Sciences（CAS） and Chinese Academy of Engineering（CAE） successively announced “2023 Research Fronts”[1] and “2023 Engineering Fronts”[2,3], respectively. Among them, agric...

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Carbon enhanced nucleophilicity of Na_(3)V_(2)(PO_(4))_(3):A general approach for dendrite-free zinc metal anodes

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Journal of Energy Chemistry 2024年第4期91卷 203-212页

作者： Sijun Wang Lingzi Hu Xiaohui Li Dan Qiu Shunhang Qiu Qiancheng Zhou Wenwen Deng Xiaoying Lu Ze Yang Ming Qiu Ying Yu institute of Nanoscience and Nanotechnology School of Physical Science and TechnologyCentral China Normal UniversityWuhan 430079HubeiChina School of Material Science and Engineering Suzhou University of Science and TechnologySuzhou 215000JiangsuChina Faculty of Science and technology Technological and Higher Education Institute of Hong KongHong KongChina

Zincophilic property and high electrical conductivity are both very important parameters to design novel Zn anode for aqueous Zn-ion batteries(AZIBs).However,single material is difficult to exhibit zincophilic property and high electrical conductivity at the same time.Herein,originating from theoretical calculation,a zincophilic particle regulation strategy is proposed to address these limitations and carbon coated Na_(3)V_(2)(PO_(4))_(3)is taken as an example to be a protective layer on zinc metal(NVPC@Zn).Na_(3)V_(2)(PO_(4))_(3)(NVP)is a common cathode material for Zn-ion batteries,which is zincophilic.Carbon materials not only offer an electron pathway to help Zn deposition onto NVPC surface,but also enhance the zinc nucleophilicity of Na_(3)V_(2)(PO_(4))_(3).Hence,this hybrid coating layer can tune zinc deposition and resist side reactions such as hydrogen generation and Zn metal corrosion.Experimentally,a symmetrical battery with NVPC@Zn electrode displays highly reversible plating/stripping behavior with a long cycle lifespan over 1800 h at2 mA cm^(-2),much better than carbon and Na_(3)V_(2)(PO_(4))_(3)solely modified Zn electrodes.When the Na_(3)V_(2)(PO_(4))_(3)is replaced with zincophobic Al2O3or zincophilic V2O3,the stability of the modified zinc anodes is also prolonged.This strategy expands the option of zincophilic materials and provides a general and effective way to stabilize the Zn electrode.

关键词： Zinc-ion batteries Zinc anode Carbon enhanced nucleophilicity Zincophilic particle regulation

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RACK1A promotes hypocotyl elongation by scaffolding light signaling components in Arabidopsis

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Journal of Integrative Plant Biology 2024年第5期66卷 956-972页

作者： Yajuan Fu Wei Zhu Yeling Zhou Yujing Su Zhiyong Li Dayan Zhang Dong Zhang Jinyu Shen Jiansheng Liang Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong higher Education institutes Department of BiologySchool of Life SciencesInstitute of Plant and Food SciencesSouthern University of Science and TechnologyShenzhen 518055China

Plants deploy versatile scaffold proteins to intricately modulate complex cell signaling.Among these,RACK1A(Receptors for Activated C Kinase 1A)stands out as a multifaceted scaffold protein functioning as a central integrative hub for diverse signaling pathways.However,the precise mechanisms by which RACK1A orchestrates signal transduction to optimize seedling development remain largely unclear.Here,we demonstrate that RACK1A facilitates hypocotyl elongation by functioning as a flexible platform that connects multiple key components of light signaling pathways.RACK1A interacts with PHYTOCHROME INTERACTING FACTOR(PIF)3,enhances PIF3 binding to the promoter of BBX11 and down-regulates its transcription.Furthermore,RACK1A associates with ELONGATED HYPOCOTYL 5(HY5)to repress HY5 biochemical activity toward target genes,ultimately contributing to hypocotyl elongation.In darkness,RACK1A is targeted by CONSTITUTIVELY PHOTOMORPHOGENIC(COP)1 upon phosphorylation and subjected to COP1-mediated degradation via the 26 S proteasome system.Our findings provide new insights into how plants utilize scaffold proteins to regulate hypocotyl elongation,ensuring proper skoto-and photo-morphogenic development.

关键词： Arabidopsis hypocotyl development light signaling components RACK1 scaffoldprotein

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Constructing a biofunctionalized 3D-printed gelatin/sodium alginate/chitosan tri-polymer complex scaffold with improvised biological andmechanical properties for bone-tissue engineering

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Bio-Design and Manufacturing 2024年第1期7卷 57-73页

作者： Amit Kumar Singh Krishna Pramanik Amit Biswas Centre of Excellence in Tissue Engineering Department of Biotechnology and Medical EngineeringNational Institute of TechnologyRourkela 769008India

Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue regeneration.We experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and differentiation.The resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)printing.Morphological studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural stability.The scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue engineering.The tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of gelatin.The enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue regeneration.In vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold surface.In addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its potential for use in bone-tissue engineering.

关键词： Scaffold Biomaterial Sodium alginate Chitosan Gelatin 3D printing Tissue engineering

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Design and identification of a double-acting piezoelectric-hydraulic hybrid actuator

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Chinese Journal of Aeronautics 2024年第3期37卷 456-467页

作者： Junjian ZHANG Zhihua FENG Key Laboratory of Precision Scientific Instrumentation of Anhui higher Education institutes University of Science and Technology of ChinaHefei 230026China

Traditional single-acting piezoelectric-hydraulic hybrid actuators usually have the problem of inertial force caused by flow pulsation of the liquid,which degrades their output performance.To suppress or solve the associated inertial force and enhance its output capabilities,this paper proposes a new type of double-acting piezoelectric-hydraulic hybrid actuator with four check valves acting as mechanical diodes.The new hybrid actuator was fabricated and its output performance was tested.When the voltage is 700 Vp-pand the bias pressure is 2 MPa,the pulsation ratesδof the new actuator at 400 Hz,500 Hz and 600 Hz are 2.29,2.08 and 1.78,respectively,whileδof the single-acting hybrid actuator under the same conditions are 10.98,11.05 and 17.12.Therefore,the liquid pulsation rate of the new hybrid actuator is significantly reduced,which is beneficial for improving the flow uniformity and weakening the influence of inertial force on the hybrid actuator.This strategy ultimately leads to a maximum no-load velocity of 168.1 mm/s at 600 Hz and a maximum blocking force of 141 N at 450 Hz for the new hybrid actuator.In addition,this strategy has the potential to be used in other electrohydrostatic actuators to improve their performance.

关键词： Double-acting Flow pulsation Inertial force Piezoelectric actuators Piezoelectric devices Piezoelectric hydraulic actuation Piezoelectric pump

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Emerging memristors and applications in reservoir computing

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Frontiers of physics 2024年第1期19卷 219-239页

作者： Hao Chen Xin-Gui Tang Zhihao Shen Wen-Tao Guo Qi-Jun Sun Zhenhua Tang Yan-Ping Jiang School of Physics and Optoelectronic Engineering Guangdong University of TechnologyGuangzhou Higher Education Mega CenterGuangzhou 510006China

Recently, with the emergence of ChatGPT, the field of artificial intelligence has garnered widespread attention from various sectors of society. Reservoir Computing (RC) is a neuromorphic computing algorithm used to analyze time-series data. Unlike traditional artificial neural networks that require the weight values of all nodes in the trained network, RC only needs to train the readout layer. This makes the training process faster and more efficient, and it has been used in various applications, including speech recognition, image classification, and control systems. Its flexibility and efficiency make it a popular choice for processing large amounts of complex data. A recent research trend is to develop physical RC, which utilizes the nonlinear dynamic and short-term memory properties of physical systems (photonic modules, spintronic devices, memristors, etc.) to construct a fixed random neural network structure for processing input data to reduce computing time and energy. In this paper, we introduced the recent development of memristors and demonstrated the remarkable data processing capability of RC systems based on memristors. Not only do they possess excellent data processing ability comparable to digital RC systems, but they also have lower energy consumption and greater robustness. Finally, we discussed the development prospects and challenges faced by memristors-based RC systems.

关键词： reservoir computing memristor resistive switching artificial synapse neuromorphic computing

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Motion of charged particles in bright squeezed vacuum

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Light(Science & Applications) 2024年第2期13卷 347-353页

作者： Matan Even Tzur Oren Cohen Solid State institute and Physics Department Technion-Israel Institute of TechnologyHaifa3200003Israel

The motion of laser-driven electrons quivers with an average energy termed pondermotive energy.We explore electron dynamics driven by bright squeezed vacuum(BSV),finding that BSV induces width oscillations,akin to electron quivering in laser light,with an equivalent ponderomotive energy.We identify closed and open trajectories of the electronic width that are associated with high harmonic generation and above-threshold ionization,respectively,similarly to trajectories of the electron position when its motion is driven by coherent light.In the case of bound electrons,the width oscillations may lead to ionization with noisy sub-cycle structure.Our results are foundational for strong-field and free-electron quantum optics,as they shed light on ionization,high harmonic generation,and nonlinear Compton scattering in BSV.

关键词： structure vacuum ionization

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Energy-Efficient Traffic Offloading for RSMA-Based Hybrid Satellite Terrestrial Networks with Deep Reinforcement Learning

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China Communications 2024年第2期21卷 49-58页

作者： Qingmiao Zhang Lidong Zhu Yanyan Chen Shan Jiang National Key Laboratory of Science and technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China The higher Educational Key Laboratory for Flexible Manufacturing Equipment Integration of Fujian Province Xiamen Institute of TechnologyXiamen 361021China China Mobile(Jiangxi)Communications Group Co. LtdYichun 336000China

As the demands of massive connections and vast coverage rapidly grow in the next wireless communication networks, rate splitting multiple access(RSMA) is considered to be the new promising access scheme since it can provide higher efficiency with limited spectrum resources. In this paper, combining spectrum splitting with rate splitting, we propose to allocate resources with traffic offloading in hybrid satellite terrestrial networks. A novel deep reinforcement learning method is adopted to solve this challenging non-convex problem. However, the neverending learning process could prohibit its practical implementation. Therefore, we introduce the switch mechanism to avoid unnecessary learning. Additionally, the QoS constraint in the scheme can rule out unsuccessful transmission. The simulation results validates the energy efficiency performance and the convergence speed of the proposed algorithm.

关键词： deep reinforcement learning energy efficiency hybrid satellite terrestrial networks rate splitting multiple access traffic offloading

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A novel evasion guidance for hypersonic morphing vehicle via intelligent maneuver strategy

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Chinese Journal of Aeronautics 2024年第5期37卷 441-461页

作者： Xun LI Xiaogang WANG Hongyu ZHOU Yu LI Department of Aerodynamics Harbin Institute of TechnologyHarbin 150001China Beijing Aerospace technology institute Beijing 100074China

This paper presents a novel evasion guidance law for hypersonic morphing vehicles,focusing on determining the optimized wing's unfolded angle to promote maneuverability based on an intelligent algorithm.First,the pursuit-evasion problem is modeled as a Markov decision process.And the agent's action consists of maneuver overload and the unfolded angle of wings,which is different from the conventional evasion guidance designed for fixed-shape vehicles.The reward function is formulated to ensure that the miss distances satisfy the prescribed bounds while minimizing energy consumption.Then,to maximize the expected cumulative reward,a residual learning method is proposed based on proximal policy optimization,which integrates the optimal evasion for linear cases as the baseline and trains to optimize the performance for nonlinear engagement with multiple pursuers.Therefore,offline training guarantees improvement of the constructed evasion guidance law over conventional ones.Ultimately,the guidance law for online implementation includes only analytical calculations.It maps from the confrontation state to the expected angle of attack and the unfolded angle while retaining high computational efficiency.Simulations show that the proposed evasion guidance law can utilize the change of unfolded angle to extend the maximum overload capability.And it surpasses conventional maneuver strategies by ensuring better evasion efficacy and higher energy efficiency.

关键词： Hypersonic vehicles Variable-sweep wings Evasion guidance Reinforcement learning Pursuit-evasion problem

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