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.

The osmolarity of a medium that is commonly used for in vitro culture (IVC) of oocytes and embryos is lower than that of oviductal fluid in pigs. In vivo oocytes and embryos can resist high osmolarities to some extent due to the presence of organic osmolytes such as glycine and alanine. These amino acids act as a protective shield to maintain the shape and viability in high osmotic environments. The aim of this study was to determine the effects of glycine or/and alanine in medium with two different osmolarities (280 and 320 mOsm) during IVC on embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. To this end, IVC was divided into two stages; the 0-2 and 3-7 days of IVC. In each stage, embryos were cultured in medium with 280, 320, or 360 mOsm and their combinations with or without glycine or/and alanine according to the experimental design. Treatment groups were termed as, for example, "T(osmolarity of a medium used in 0-2 days of IVC)-(osmolarity of a medium used in 3-7 days of IVC)" T280-280 was served as control. When PA embryos were cultured in medium with various osmolarities, T320-280 showed a significantly higher blastocyst formation (29.0%) than control (22.2%) and T360-360 groups (6.9%). Glycine treatment in T320-280 significantly increased blastocyst formation (50.4%) compared to T320-280 only (36.5%) while no synergistic was observed after treatment with glycine and alanine together in T320-280 (45.7%). In contrast to PA embryonic development, the stimulating effect by the culture in T320-280 was not observed in SCNT blastocyst development (27.6% and 23.7% in T280-280 and T320-280, respectively) whereas the number of inner cell mass cells was significantly increased in T320-280 (6.1 cells vs. 9.6 cells). Glycine treatment significantly improved blastocyst formation of SCNT embryos in both T280-280 (27.6% vs. 38.0%) and T320-280 (23.7% vs. 35.3%). Our results demonstrate that IVC in T320-280 and treatment with glycine improves blastocyst formation of PA and SCNT embryos in pigs.

Nitric oxide (NO) has an important role in oocyte maturation and embryonic development in mammals. This study examined the effect of exogenous NO donor S-nitroso-N-acetylpenicillamine (SNAP) in a maturation medium on meiotic progression and embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. When oocytes were exposed to 0.1 μM SNAP for first 22 h of in vitro maturation (IVM) in Experiment 1, SNAP significantly improved blastocyst development in both defined and standard follicular fluid-supplemented media compared to untreated control (48.4 vs. 31.7-42.5%). SNAP treatment significantly arrested meiotic progression of oocytes at the germinal vesicle stage at 11 h of IVM (61.2 vs. 38.7%). However, there was no effect on meiotic progression at 22 h of IVM (Experiment 2). In Experiment 3, when oocytes were treated with SNAP at 0.001, 0.1 and 10 μM during the first 22 h of IVM to determine a suitable concentration, 0.1 μM SNAP (54.2%) exhibited a higher blastocyst formation than 0 and 10 μM SNAP (36.6 and 36.6%, respectively). Time-dependent effect of SNAP treatment was evaluated in Experiment 4. It was observed that SNAP treatment for the first 22 h of IVM significantly increased blastocyst formation compared to no treatment (57.1% vs. 46.2%). Antioxidant effect of SNAP was compared with that of cysteine. SNAP treatment significantly improved embryonic development to the blastocyst stage (49.1-51.5% vs. 34.4-37.5%) irrespective of the presence or absence of cysteine (Experiment 5). Moreover, SNAP significantly increased glutathione (GSH) content and inversely decreased the reactive oxygen species (ROS) level and mitochondrial oxidative activity in IVM oocytes. SNAP treatment during IVM showed a stimulating effect on in vitro development of SCNT embryos (Experiment 7). These results demonstrates that SNAP improves developmental competence of PA and SCNT embryos probably by maintaining the redox homeostasis through increasing GSH content and mitochondrial quality and decreasing ROS in IVM oocytes.

This study examined the overdose toxicity of Super-Neophensan, containing florfenicol and acetaminophen, upon pigs. SNP-3.0 (n=10) was administered at the dosage level of 3 kg/ton feed for 7 consecutive days, which is 3 times the recommended dose based on the guidelines of the manufacturer, and the control group (CON) (n=10) was administered the normal diet without the drug. The body weight, weight gain and feed efficiency in SNP-3.0 treated with the drug for 14 days post-administration showed no significant differences compared with those in CON. In hematological and blood biochemical analyses, all parameters were not affected by over-dosage of the drug. In the same way, there were no significant differences between SNP-3.0 and CON on markers for liver and kidney functions. As no adverse effects were observed with the drug in an overdose oral toxicity test, this study suggests that the drug was identified as a safe agent in pigs administered with three times the recommended dose.

A study of the tissue depletion of florfenicol (FFC) administered orally to pigs at a dose of 0.05 kg/ton feed for 7 days was performed. Sixteen healthy cross swine were administered with FFC. Four treated animals were arbitrarily selected to be sacrificed 1, 3 and 5 days after the end of treatment. FFC residue concentrations in muscle, liver, kidney, and fat were determined using high-performance liquid chromatography (HPLC) with ultraviolet photometric detector at 230 nm. The correlation coefficient (R2) of the calibration curve for florfenicol amine (FFCa) was > 0.997 and the limits of detection and quantification were 0.012 and 0.040 μg/mL, respectively. Recovery rates in swine edible tissues ranged from 79.1 to 93.5%. In the FFC-treated group, FFC residues at 3 days post-treatment were below the maximum residue limits (MRLs) in muscle, kidney and fat, and those at 5 days post-administration were below the MRLs in all edible tissues. These results suggest that the withdrawal period of FFC after the drug treatment might be 5 days, which is a sufficient amount of time for reduction of the FFC residues below the MRLs in all edible tissues.

국가기관과 기업은 정비사를 양성을 위한 고등학교부터 대학교, 기업 훈련센터 같은 교육기관을 만들어 숙련된 정비사로 훈련시키려고 많은 노력을 하고 있다. 하지만 교재를 이용한 이론교육과 현장에서 사용하지 않는 장비를 이용한 실습교육으로는 제대로 된 정비교육을 진행하지 못하며 특수 장비를 활용한 교육이나 위험한 상황을 가정한 정비의 교육은 매우 위험하여 영상이나 사진으로 교육을 진행하고 있었다. 최근에는 VR과 AR을 접목하여 단순정비에서 특수정비까지 시뮬레이션으로 안전하게 상황을 체험하고 문제를 해결하는 효과적인 교육 시뮬레이션이 연구되고 개발되는 사례가 많이 있다. 본 논문에서는 다누리 VR과 DisTi Engine, Remote AR을 비교분석하고, 유니티 엔진 기반으로 외부에서 전달된 정보를 기반으로 콘텐츠를 디바이스 화면에 최적화하여 출력하는 AR API 를 소개하고, VR 디바이스인 HTC Vive의 컨트롤러와 HMD의 정보를 실시간으로 수집하고 수집된 정보를 파일에 저장하는 VR API를 구현한 사례를 소개했다. 본 연구에서 구현한 API를 사용하면 콘텐츠를 제작할 때 도움을 줄 수 있을 것이다.

Coke aggregates and carbon artifacts were produced to investigate the interactions of coke and pitch during the kneading process. In addition, the kneading ratio of the coke and binder pitch for the coke aggregates was controlled to identify the formation of voids and pores during carbonization at 900°C. Experiments and thermogravimetric analysis revealed that carbon yields were improved over the theoretical yield calculated by the weight loss of the coke and binder pitch; the improvement was due to the binding interactions between the coke particles and binder pitch by the kneading process. The true, apparent, and bulk densities fluctuated according to the kneading ratio. This study confirmed that an excessive or insufficient kneading ratio decreases the density with degradation of the packing characteristics. The porosity analysis indicated that formation of voids and pores by the binder pitch increased the porosity after carbonization. Image analysis confirmed that the kneading ratio affected the formation of the coke domains and the voids and pores, which revealed the relations among the carbon yields, density, and porosity.

Generally, in vivo, primary oocytes are grown and matured into secondary oocytes in the ovarian follicles. Quality of the oocytes matured in vivo is higher than that of oocytes matured in vitro, indicating the importance of materializing the microenvironment of ovarian follicles for production of high quality oocyte. Therefore, we tried to mimic the stiffness of ovarian follicles using an agarose as a biocompatible natural polymer. Unfortunately, to date, there are no many reports on whether the quality of porcine oocytes can be increased effectively under the soft matrix. Accordingly, we tried to evaluate the effects of IVM using different mechanical properties of agarose substrate on developmental competence of porcine oocytes. Agarose substrate was constructed and cumulus-oocyte-complexes (COCs) retrieved from porcine medium antral follicles were matured on non-coated (control) culture dish or dishes coated with 1% and 2% (w/v) agarose substrate. Then, cumulus expansion, embryonic development after parthenogenetic activation, and gene expression level were analyzed and compared. As the results, significant increase in blastocyst formation and cumulus expansion were detected in COCs matured on 1% (w/v) agarose substrate compared with control. Moreover, oocytes of COCs matured on 1% (w/v) agarose substrate showed significantly higher BMP15 expression level compared with control. Pro-apoptotic gene BAX expression was significantly increased in oocytes of COCs matured on 2% (w/v) agarose substrate compared with control. In the glycolytic enzyme phosphofructokinase (PFKP) gene expression, cumulus cells of COCs matured on agarose substrate showed significantly higher PFKP expression than control while they showed significantly lower BAX expression than control. These results demonstrated that quality of porcine oocytes could be increased efficiently by the IVM of immature oocytes on the soft culture matrix using agarose.