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보행 모의 실험을 위한 발목 없는 하지 외골격 로봇의 지면 접촉 모델 최적화
최기명,김상형,조창현 한국로봇학회 2023 로봇학회 논문지 Vol.18 No.4
The purpose of this study is to optimize parameters of a contact model to obtain similar ground contact force of human walking. Dynamic walking simulation considering ground contact is performed to determine load specifications when developing walking assist robots. Large contact forces that are not observed in actual experimental data occur during the simulation at the initial contact (e.g., heel contact). The large contact force generates unrealistic large joint torques. A lower exoskeleton robot with no ankles is developed with the Matlab simscape and the nonlinear hyper volumetric contact model is applied. Parameters of the nonlinear hyper volumetric model were optimized using actual walking contact force data. As a result of optimization, it was possible to obtain a contact force pattern similar to actual walking by removing the large contact force generated during initial contact.
산양유 및 산양유 발효유가 웅성 설치류의 생식기능과 지구력에 미치는 영향에 관한 연구
임경순,강재구,최기명,배창준,조우제,Im, Kyung-Soon,Kang, Jae-Ku,Choi, Ki-Myung,Pae, Chang-Joon,Joh, Woo-Jea 대한생식의학회 2000 Clinical and Experimental Reproductive Medicine Vol.27 No.4
Objective: The purpose of this study was to evaluate effects of goat milk and fermented goat milk on reproductive function and stamina of male rodent. Methods: Experiment I: Male ICR mouse was divided into four groups. Group 1 none-treated control; Group 2 received saline; Group 3 received cow milk 10 ml/kg per day for 15 days; Group 4 received goat milk 10 ml/kg per day for 15 days. The cauda epididymal sperm motility and testicular sperm production were investigated. Experiment II: Male SD rat was divided into three groups. Group 1 received saline; Group 2 received goat milk 10 ml/kg per day for 28 days; Group 3 received fermented goat milk 10 ml/kg per day for 28 days. The cauda epididymal sperm motility and testicular sperm production were also investigated. The concentration of testosterone in serum at 1 and 3 weeks after treatment was determined using Immulite 2000 kit. Testes, epididymis, prostate, and seminal vesicle were weighed. Experiment III: Male ICR mouse was divided into four groups. Group 1 none-treated control; Group 2 received saline; Group 3 received goat milk 10 ml/kg per day for 4 weeks; Group 4 received fermented goat milk 10 ml/kg per day for 4 weeks. After treatment, the mouse was forced to swim to test for stamina. Results: In Experiment I, the cauda epididymal sperm motility after in vitro culture for 1 or 3 h was significantly (p<0.05) higher in cow milk and goat milk than in the control and saline. There was no significant difference in the cauda epidymal sperm motility between cow and goat milk. The testicular spermatid number was significantly (p<0.01) higher in goat milk (222.8${\times}10^6$) than in the control (108.6), saline (98.2), and cow milk (118.2). In Experiment II, the cauda epididymal sperm motility after in vitro culture for 1 h was significantly (p<0.05) higher in fermented goat milk than in saline and goat milk. There was no significant difference in the cauda epidymal sperm motility between saline and goat milk but goat milk showed slightly higher sperm motility than saline. After in vitro culture for 3 h, the cauda epididymal sperm motility was significantly (p<0.01) higher in fermented goat milk and goat milk than in saline. The testicular spermatid number was significantly (p<0.05) higher in goat milk than in saline, and significantly (p<0.01) higher in fermented goat milk than in saline. And the serum testosterone levels of rats administered with goat milk or fermented goat milk were increased but were no significant difference among three groups. Also the prostate weight was significantly (p<0.05) increased in the goat and fermented goat milk. In Experiment III, the swimming time in the goat milk and fermented goat milk groups was significantly (p<0.01) longer than in the control and saline. There was no significant difference in the swimming time between goat and fermented goat milk but the fermented goat milk showed slightly longer swimming time than the goat milk. Conclusion: The cauda epididymal sperm motility, the testicular spermatid number and stamina were improved when the mice and rats were drunk with goat milk or fermented goat milk.
장석민,강재구,최기명,김홍래,진동일 충남대학교 농업과학연구소 2007 농업과학연구 Vol.34 No.1
This study was conducted to evaluate the response of CIDR-S on estrus synchronization of dairy goats and the effect of artificial insemination on conception rate. Estrus synchronization of sexually matured Saanen goats was induced with insertion of CIDR-S into vagina for 15 days and injection of 500 IU PMSG before removal of CIDR-S. Artificial insemination was conducted using liquid or frozen semen by intra-cervical insemination with synchronized does. Estrus synchronization was 90% using CIDR-S insertion for 15 days. Conception rate of inseminated does was 20% - 25%, while that of natural mated does was 100%. These results suggested that synchronization of dairy goats can be successfully induced and artificial insemination method has to be improved for the practical use in dairy goats.
한나래,박혜진,윤정임,최기명,이은송,이승태 사단법인 한국동물생명공학회 2018 한국동물생명공학회지 Vol.33 No.4
To date, there are no protocols optimized to the effective separation of spermatogonial stem cells (SSCs) from testicular cells derived from mouse testes, thus hindering studies based on mouse SSCs. In this study, we aimed to determine the most efficient purification method for the isolation of SSCs from mouse testes among previously described techniques. Isolation of SSCs from testicular cells derived from mouse testes was conducted using four different techniques: differential plating (DP), magnetic-activated cell sorting (MACS) post-DP, MACS, and positive and negative selection double MACS. DP was performed for 1, 2, 4, 8, or 16 h, and MACS was performed using EpCAM (MACSEpCAM), Thy1 (MACSThy1), or GFR α1 (MACSGFRα1) antibodies. The purification efficiency of each method was analyzed by measuring the percentage of cells that stained positively for alkaline phosphatase. DP for 8 h, MACSThy1 post-DP for 8 h, MACSGFRα1, positive selection double MACSGFRα1/EpCAM, and negative selection double MACSGFRα1/α-SMA were identified as the optimal protocols for isolation of SSCs from mouse testicular cells. Comparison of the purification efficiencies of the optimized isolation protocols showed that, numerically, the highest purification efficiency was obtained using MACSGFRα1. Overall, our results indicate that MACSGFRα1 is an appropriate purification technique for the isolation of SSCs from mouse testicular cells.
Recent vaccine technology in industrial animals
김현일,이유경,강상철,한범구,최기명 대한백신학회 2016 Clinical and Experimental Vaccine Research Vol.5 No.1
Various new technologies have been applied for developing vaccines against various animal diseases. Virus-like particle (VLP) vaccine technology was used for manufacturing the porcine circovirus type 2 and RNA particle vaccines based on an alphavirus vector for porcine epidemic diarrhea (PED). Although VLP is classified as a killed-virus vaccine, because its structure is similar to the original virus, it can induce long-term and cell-mediated immunity. The RNA particle vaccine used a Venezuela equine encephalitis (VEE) virus gene as a vector. The VEE virus partial gene can be substituted with the PED virus spike gene. Recombinant vaccines can be produced by substitution of the target gene in the VEE vector. Both of these new vaccine technologies made it possible to control the infectious disease efficiently in a relatively short time.
강재구,박광욱,정연구,유정수,김용기,이승현,홍승표,최기명,허기남,설재구,이종호,진동일,박창식,서정선,이향우,한정환 생화학분자생물학회 2007 Experimental and molecular medicine Vol.39 No.1
Various cell types in higher multicellular organisms are genetically homogenous, but are functionally and morphologically heterogeneous due to the differential expression of genes during development, which appears to be controlled by epigenetic mechanisms. However, the exact molecular mechanisms that govern the tissue-specific gene expression are poorly understood. Here, we show that dynamic changes in histone modifications and DNA methylation in the upstream coding region of a gene containing the transcription initiation site determine the tissue-specific gene expression pattern. The tissue-specific expression of the transgene correlated with DNA demethylation at specific CpG sites as well as significant changes in histone modifications from a low ratio of methylated H3- lysine 4 or acetylated H3-lysine 9, 14 to acetylated H4 to higher ratios. Based on the programmed status of transgene silenced in cloned mammalian ear- derived fibroblasts, the transgene could be reprogrammed by change of histone modification and DNA methylation by inhibiting both histone deacetylase and DNA methylation, resulting in high expression of the transgene. These findings indicate that dynamic change of histone modification and DNA methylation is potentially important in the establishment and maintenance of tissue-specific gene expression.