Spermatogenesis of Male Patients with Congenital Hypogonadotropic Hypogonadism Receiving Pulsatile Gonadotropin-Releasing Hormone Therapy Versus Gonadotropin Therapy: A Systematic Review and Meta-Analysis

Wei Chao,Long Gongwei,Zhang Yucong,Wang Tao,Wang Shaogang,Liu Jihong,Ma Delin,Liu Xiaming 대한남성과학회 2021 The World Journal of Men's Health Vol.39 No.4

Purpose: Pulsatile gonadotropin-releasing hormone (GnRH) therapy and gonadotropin therapy (GT) were widely used for male patients with congenital hypogonadotropic hypogonadism (CHH), but their efficacy was not well compared before. We conducted this meta-analysis to compare the efficacy of restoring fertility using these two therapies. Materials and Methods: PubMed, Web of Science, and Scopus were systematically searched for comparative studies evaluating the efficiency of GnRH therapy and GT for male patients with CHH. For continuous outcomes, the weighted mean difference (WMD) was used to measure the difference, whereas the risk ratio with 95% confidence interval was calculated for binary variables. Results: Overall, eight articles from seven studies with 420 patients enrolled were included in the analysis. Patients from the two different groups were determined to be comparable in age, proportion with Kallmann syndrome, percentage of cryptorchidism and pretreatment hormones (follicular-stimulating hormone, luteinizing hormone, and testosterone). GnRH therapy was related to a larger testicular volume (standardized mean difference=-1.43; p=0.01) and earlier spermatogenesis (WMD=- 5.30 months; p=0.004) compared to GT. However, the difference in the rate of positive sperm detection (p=0.08), sperm concentration (p=0.37), and pregnancy rate (p=0.11) were not significant. Allergic reactions mostly occurred during GnRH therapy, while GT was related to a higher incidence of gynecomastia and acne. Conclusions: Compared to GT, GnRH was related to earlier spermatogenesis and less estradiol-related adverse reactions, although there were no significant differences in spermatogenesis rate, sperm concentration, and pregnancy rate. High-quality randomized controlled trials are needed for future research.

Equivalence Analysis of Virtual Synchronous Machines and Frequency‑Droops for Inertia Emulation in Power Systems with Converter‑Interfaced Renewables

Weichao Zhang,Xiangwu Yan 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

In converter-based AC microgrids, the frequency-droop is widely applied. As a considerable share of installed capacity is replaced by renewable generation, the virtual synchronous machine (VSM) algorithm is presented to address stability issues caused by low-inertia converter interfaces. Recently, droop control loops are also modifed to improve stability. The VSM and the frequency-droop are both derived from the property imitation of synchronous generators (SGs) while researched independently. In this paper, by simplifcations in the steady state, the expression of the inertia emulation of the VSM algorithm based on the second-order SG model is linearized as a frst-order ordinary diferential equation. In frequency-droop loops, as the instantaneous power components are commonly passed through a low-pass flter for disturbance rejection, the system function of the droop control can also be transformed into a frst-order ordinary diferential equation, which is equivalent to that of the VSM under certain conditions. In terms of the inertia constant, the swing equation is normalized under per unit representation. By the same simplifcation in the VSM linearization, the equivalence between the linearized VSM and the SG is also demonstrated. Therefore, the equivalence among SGs, the VSM, and the frequency-droop are summarized, which provides insights for coordinative control of power converters integrated into current SG dominating power systems. For a specifc synchronous generator, the equivalence conditions are verifed by simulation.

Air horizontal jets into quiescent water

Weichao Li,Zhaoming Meng,Jianchuang Sun,Weihua Cai,Yandong Hou Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

Gas submerged jet is an outstanding thermohydraulic phenomenon in pool scrubbing of fission products during a severe nuclear accident. Experiments were performed on the hydraulic characteristics in the ranges of air mass flux 0.1-1400 kg/m²s and nozzle diameter 10-80 mm. The results showed that the dependence of inlet pressure on the mass flux follows a power law in subsonic jets and a linear law in sonic jets. The effect of nozzle submerged depth was negligible. The isolated bubbling regime, continuous bubbling regime, transition regime, and jetting regime were observed in turn, as the mass flux increased. In the bubbling regime and jetting regime, the air volume fraction distribution was approximately symmetric in space. Themelis model could capture the jet trajectory well. In the transition regime, the air volume fraction distribution loses symmetry due to the bifurcated secondary plume. The Li correlation and Themelis model showed sufficient accuracy for the prediction of jet penetration length.

Modelling and Development of Control Algorithm of Endoscopy

Ma, Weichao,Lee, Sanghyuk Convergence Society for SMB 2014 융합정보논문지 Vol.4 No.2

본 논문에서는 효율적인 제어를 위하여 캡슐 앤도스코피에 대한 모델링을 실시하였다. 방법론적으로 루그레 모델에 대한 시스템 특성파악을 위한 수학적 모델링을 이용하였다. 비선형 마찰 모델인 루그레 모델에 바탕을 둔 stick-slip 모션 시스템이 인체내에서의 캡슐 앤도스코피의 활동을 묘사하는 시뮬레이션 모델로 이용하였다. 다양한 상황을 고려하여 루그레 마찰모델에 대한 시뮬레이션을 Matlab Simulink 를 작성하여 수행하였다. 전체적인 모션과 파라미터의 영향이 엔도스코피의 속도에 미치는 영향에 대한 것에 주안을 두어 실시하였다. In this paper, basic backgrounds about capsule endoscopy are introduced, and the aims and objectives are also illustrated. Methodology and mathematical model for LuGre model were investigated to analyse system characteristics. A nonlinear friction model, the stick-slip motion system based on LuGre friction model was used to simulate the motion of capsule endoscopy inside human body. Under the different situation, LuGre friction model was simulated by Matlab Simulink software. The entire cycle of motion and the influence of parameters towards to velocity are fully simulated.

Ginseng saponin metabolite 20(S)-protopanaxadiol relieves pulmonary fibrosis by multiple-targets signaling pathways

Guoqing Ren,Weichao Lv,Yue Ding,Lei Wang,ZhengGuo Cui,Renshi Li,Jiangwei Tian,Chaofeng Zhang 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.4

Modulation method of parallel interleaved three‑level inverter considering neutral point potential and phase current balance

Ying Zhong,Weichao Li,Liang Zhou,Chen Deng,Jinyang Han 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.2

The capacity and equivalent switching frequency of parallel interleaved inverters can be increased, but there are problems with neutral point potential balance and parallel bridge circulating current. This paper regards the parallel three-level inverter as a five-level inverter and five-level space vector integrated modulation is applied. On this basis, a neutral-point potential control strategy based on the mid-point charge to calculate the adjustment factor k is proposed. By further meticulously partitioning specific sector regions, the selection method of redundant vectors in the switching sequence is optimized without increasing the switching times, and the midpoint voltage ripple is reduced. Then, the redundant state allocation in the process of splitting the five-level into three-level is used as a new degree of freedom to suppress the circulating current of the parallel bridge, therefore realizing the control of voltage and current sharing. Finally, simulation and experiments verify the correctness and effectiveness of the method.

DISTRIBUTED FORMATION CONTROL OF HOMOGENEOUS VEHICLE PLATOON CONSIDERING VEHICLE DYNAMICS

Liwei Xu,Weichao Zhuang,Guodong Yin,Chentong Bian 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.6

Vehicle dynamics plays a significant role on the formation of a vehicle platoon, especially at high speed condition. This paper proposes a distributed platoon formation framework for homogeneous autonomous vehicles which takes the vehicle dynamics into consideration. The boundaries of vehicle stability are firstly calculated by considering both lateral dynamics and actuator saturation. By combining the stability boundaries with multi-objective flocking (MOF) algorithm, a distributed formation controller is designed, which can form the vehicle platoon with high cruising speed steadily and rapidly. In addition, a low-level tracking controller is proposed to constitute a hierarchical control architecture which can achieve stable and accurate formation of platoon. Simulation results show the proposed platoon formation controller achieves safe, stable and rapid platoon formation than the traditional MOF-based formation controller which does not consider the vehicle dynamics.

Thermodynamic Performance Analysis of New Paper Machine Air Hood Heat Recovery System

Yan Yan,Wang Weichao,Pan Zhao 한국펄프·종이공학회 2022 펄프.종이기술 Vol.54 No.6

In this paper, a new heat recovery system of hot air hood of paper machine is proposed, the thermodynamic model of the system is established, and the effect of different thermal parameters on the heat recovery efficiency of the system is studied. The results indicate that both the recovered energy and the proportion of exhaust air passing through the latent heat exchanger attenuate as fresh air temperature increase and fresh air moisture content decrease. The system heat recovery increasing with rising of exhaust temperature. Exhaust temperature and exhaust relative humidity have different effects on sensible and latent heat recovery. The maximum value of proportion of exhaust air passing through latent heat exchanger appears when the exhaust relative humidity is 35.8%. Overall, the fresh air temperature and the exhaust relative humidity have great influence on the heat recovery efficiency.

Reliability Analysis and Prediction on Tunnel Roof under Blasting Disturbance

Pengfei Wu,Tianjiao Yang,Weichao Jia 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.9

The parameters of underground structure have the characteristics of large spatial heterogeneity and strong uncertainty. Recently, people gradually begin to use the idea of probability to analyze the safety of underground structures. However, few articles analyze the dynamic response of structural reliability. In this paper, the reliability of tunnel roof under blasting disturbance is studied, and the influence of the number of disturbances and the distribution of random variables on the structural reliability is analyzed. The prediction model of structural reliability is proposed. The sensitivity of different parameters to the structural reliability is discussed. The results show that the traditional method of evaluating the structural safety status is more dependent on the design value of each parameter. However, the design value does not represent the true state of the structure in a completely accurate way, which will result in a certain deviation between the assessment of the structural safety state and the actual state. Single disturbance has a limited impact on the structural reliability, while repeated disturbances can still have a noticeable effect on the structural reliability. When the disturbance reaches a certain number of times, the reliability of the structure can drop sharply. This paper proposes the prediction function of structure reliability according to the decay of structure reliability after blasting disturbance. Only a small number of parameters are needed to predict the structure reliability at different times. The error between the forecast results and the actual results is about 1%. With the increase of the number of blasting disturbances, the sensitivity coefficient of the structural resistance factor gradually decreases, and the sensitivity coefficient of the loaded effect gradually increases. The control of the blasting strength should be gradually increased to ensure the structural safety. Even if the mean and mean square error of random variables are the same, different distribution forms will have a great impact on the calculation results.

Enhanced Reactive Dye Inkjet Printing Performance of Antimicrobial Silk Fabrics Surface Modified with Plasma and Chitosan

Yi Xu,Kuanjun Fang,Weichao Chen,Xiangwu Zhang,Chunming Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

This paper develops a new clean production technology combining atmospheric pressure plasma jets and nanochitosanto prepare strong and durable bio-based coatings for improving the inkjet printing performance of antimicrobial silkfabrics. The key contribution of this study is to introduce green and environmental friendly production methods, avoiding theuse of chemicals and pollution caused by dye hydrolysis in traditional ways. By contradistinctive experiments, we presentdirect empirical evidence that the plasma-chitosan treatment can significantly improve the hydrophilicity of the silk surfaces. Wettability test indicates that the infiltration time of droplet on the surface of modified silk fabric was only 1/12 of the timespent on the untreated sample. The study of reactive dye inkjet printing illustrates that the antibleeding property on modifiedsamples was evidently enhanced. Meanwhile, in respect of color fixation of reactive dyes, there was also an increase in K/Svalue on modified samples, ranging from 76 % to 214 % in color depth of the four-color print blocks, even after gas steamingand washing. Scanning electron microscope (SEM) observation reveals that the surface of silk fibers modified with plasma iscovered with firmer and more uniform chitosan coatings in terms of morphology change. X-ray photoelectron spectroscopy(XPS) analysis verifies that the content of oxygenous groups on the silk fabric processed by plasma-chitosan increased bymore than 42 %. As to the antibacterial effect of nano-chitosan, the photographs of inhibition zone shows that the plasmaprocessing effectively enhanced the durability of chitosan against B. subtilis, and thus prepared long-lasting antibacterial silkfabric. Furthermore, measurements of washing and rubbing color fastness prove that the plasma-chitosan treated fabrics stillhad excellent inkjet printing effect even after 45 cycles of soaping. Taken together, it turns out that such nontoxic,nonpolluting, low energy-consumed chitosan coating combining with plasma can explicitly provide an innovative option forthe production of inkjet printing on natural fabrics.