This study was investigated to test whether the zygote recognized the topoisomerase II beta (TOP2B) mediated DNA fragmentation in epididymal spermatozoa or the nuclease degradation in vas deferens spermatozoa by testing for the presence of gammaH2AX (γH2AX). The γH2AX is phosphorylation of histone protein H2AX on serine 139 occurs at sites flanking DNA double-stranded breaks (DSBs). The presence of γH2AX in the pronuclei of mouse zygotes which were injected with DNA broke epididymal spermatozoa was tested by immunohistochemistry at 5 and 9 h post fertilization, respectively. Paternal pronuclei that arose from epididymal spermatozoa treated with divalent cations did not stain for γH2AX at 5 h. On the other hand, in embryos injected with vas deferences spermatozoa that had been treated with divalent cations, γH2AX was only present in paternal pronuclei, and not the maternal pronuclei at 5 h. Interestingly, both pronuclei stained positively for γH2AX for all treatments and controls at 9 h after sperm injection. In conclusion, the embryos recognize DNA that is damaged by nuclease, but not by TOP2B because H2AX in phosphorylated in paternal pronuclei resulting from spermatozoa treated with fragmented DNA from vas deferens spermatozoa treated with divalent cations, but not from epididymal spermatozoa treated the same way.

Heavy metals in stream water and sediments around industrial complex were studied in order to assess the contamination and to identify the potential source of metals. High variability has been observed for both dissolved and particulate phases in stream water with coefficient of variation (CV) ranging from 1.3 to 2.8. The highest metal concentrations in both phases were observed in Gunja for Ni and Cu, in Jungwang for Zn and Pb and in Shiheung for Cd, respectively. These results indicate that the different metal sources could be existing. The concentrations of the heavy metals in sediments decreased in the order of Cu>Zn>Pb>Cr>Ni>As>Cd>Hg, with mean of 2,549, 1,742, 808, 539, 163, 17.1, 5.8, 0.07 mg kg-1, respectively. Mean of metal concentrations (except for As) in sediments showed the highest values at Shiheung stream comparing with other streams. In sediments, the percent exceedance of class II grade that metal may potentially harmful impact on benthic organism for Cr, Ni, Cu, Zn, Cd, Pb was about 57%, 62%, 84%, 60%, 68%, 81% for all stream sediments, respectively. Sediments were classified as heavily to extremely polluted for Cu and Cd, heavily polluted for Zn and Pb, based on the calculation of Igeo value. About 59% and 35% of sediments were in the categories of “poor” and “very poor” pollution status for heavy metals. Given the high metal concentrations, industrial wastes and effluents, having high concentrations of most metals originated from the manufacture and use of metal products in this region, might be discharged into the stream through sewer outlet. The streams receive significant amounts of industrial waste from the industrial facilities which is characterized by light industrial complexes of approximately 17,000 facilities. Thus, the transport of metal loads through streams is an important pathway for metal pollution in Shihwa Lake.

Graphene and Fe3O4 were bound by electrostatic attraction and prepared by effective reduction through microwave treatments. As a result of fabricating graphene with Fe3O4 as a composite material, it has been confirmed that it contributes to the structural improvement in graphene stabilization and at the same time, it shows improved electrochemical performance through improved charge transfer. It was also confirmed that the crystalline Fe3O4 was uniformly dispersed in the rGO sheet, effectively blocking the reaggregation due to the van der Waals interaction between the neighboring rGO sheets. The structural analysis of prepared composites was confirmed by transmission electron microscopy, and X-ray diffractometer. Electrochemical properties of composites were studied by cyclic voltammetry, galvanostatic charge–discharge curves, and electrochemical impedance spectroscopy. The Fe3O4 (0.4 M)/rGO composite showed a high specific capacitance of 972 F g−1 at the current density of 1 A g−1 in 6 M KOH electrolyte, which is higher than that of the pristine materials rGO (251 F g−1) and Fe3O4 (183 F g−1). Also, the prepared composites showed a very stable cyclic behavior at high current density, as well as an improvement in comparison with pristine materials in terms of resistance.

This study presents how two types of integrated science and engineering lessons affect students’ engineering problem solving skills and their perceptions of engineering. In total, 146 middle school students participated in this study. Eighty-six students participated in the Type I lesson (complete engineering design lesson with a science knowledge application) and 60 students participated in the Type II lesson (engineering design without a science knowledge application). Two main datasets, (1) students’ Creative Engineering Problem Solving Propensity (CEPSP) measurement scores and (2) open-ended survey questions about students’ perceptions of engineering, were collected before and after the lessons. The results of this study show that after participating in the Type I lesson, students’ CEPSP scores significantly increased, whereas the CEPSP scores of the students who participated in the Type II lesson did not increase significantly. In addition, students who participated in the Type I lesson perceived engineering and the engineering integrated science lesson differently compared to the students who participated in the Type II lesson. The results of this study show that engineering integrated science, technology, engineering & mathematics (STEM) lessons should include a complete engineering design and a science knowledge application to improve students’ engineering problem solving skills.

본 연구에서는 멸종위기 야생생물 II급이자 천연기념물(453호)인 한국산 남생이 Mauremys reevesii가 집단으로 발견된 경북 경주시 내 저수지의 특성을 파악하였다. 또한 서식지 내에서 남생이의 생존에 직⋅간접으로 위협이 되는 생물 및 비생물적 요인들을 조사하였다. 남생이가 집단으로 발견된 지역은 농업용으로 관리 중인 저수지이다. 서식지 주변에는 수몰나 무 지대, 석축, 산림, 갈대밭, 농경지(논)가 형성되어 있었다. 저수지 내 모든 남생이들은 저수지 북면에 형성되어 있는 수몰나무 지에서만 발견되었다. 2018년 5월 10일과 8월 9일에 걸친 현지 조사에서 발견된 남생이의 수는 각각 28 개체와 21 개체였다. 남생이에게 위협이 되는 붉은귀거북과 황소개구리가 서식지 주변에서 다수 발견되었다. 문화재 발굴 작업, 화학 비료 그리고 생활 쓰레기가 저수지 곳곳에서 발견되었으며, 이는 남생이에게 큰 위협요인이 될 것으로 추정된다. 당해 연도 태어난 개체들은 확인되지 않았지만 아성체들이 다수 발견된 것을 고려하면 자연 번식이 충분히 이루어지고 있는 것으로 추정된다. 하지만 경쟁종인 붉은귀거북의 아성체 역시 발견되었기 때문에 남생이에게는 지속적인 문제가 될 수 있다. 연구의 결과를 종합하면, 국내 최대 규모의 남생이 개체군을 보호하기 위한 방법으로는 서식지 내 보전 방법이 적극적으로 고려되어야 할 것으로 판단된다.

본 연구는 2012년 1월부터 2019년 1월까지 과천경마공원에서 경주한 더러브렛, 6,762두의 주파기록, 총 82,796개를 이용하여 동기군의 구성을 조사하기 위하여 수행되었다. 모든 경주거리에서 우승마의 주 파기록이 1초 감소하면 해당 경주의 평균 주파기록은 0.89초에서 0.99초 감소하였다. 주파기록에 대한 동기군의 효과는 총변이의 약 41%를 차지하였으며, 참가경주의 효과는 일괄적으로 모든 경주거리에서 가장 크게 나타났다. 동기군을 포함한 모형(Ⅰ)과 우승마 기록을 포함한 모형(Ⅱ)에서 추정된 주파기록에 대한 유전분산은 각각 0.4760과 0.4148, 유전력과 반복력은 각각 0.26, 0.47과 0.22, 0.40이었다. 모형 Ⅱ에서 추정된 유전분산과 유전력은 모형 1에 비하여 각각 13%와 15% 감소하는 것으로 나타났으며, 우승마의 주파기록을 환경효과로 모형에 포함하는 것보다는 동기군을 포함하는 것이 주파기록을 량하는데 있어서 더 유리할 것으로 판단되었다.

This research develops an under-investigated aspect of the business literature regarding firm-created and user-generated social media communication and their influence on purchase intention of endorsed fashion products. The results indicate that (i) brand equity mediates the relationship between social media communication and purchase intention of endorsed fashion products, and (ii) the mediational role of brand equity is further moderated by the consumer’s self-congruity with fashion brands.

PURPOSES : In this study, we evaluated the quality levels of abrasion resistance and freeze-thaw resistance to the surface layer (colored layer) by using an overseas abrasion resistance test method to confirm the quality suitability of the concrete block surface for a domestic production permeable block. METHODS : In this study, a new evaluation item for increased durability apart from the quality standard of the permeable block was considered, namely, evaluation of the durability of the surface layer and the freeze-thaw resistance of the permeable block itself by EN 1338, ASTM C 779, 994, and GR 4009 (KS F 4419). RESULTS : The abrasion resistance test for the permeable block revealed that there were relative differences according to the different test methods. However, it was observed that if the ASTM C 779 test results did not meet the wear resistance quality standards, it did not satisfy ASTM C 944 and EN 1338. The ASTM C 779 test result was analyzed to have the highest objectivity and discernment, and this test method was proposed as a permeable block wear test method. In addition, the freeze-thaw resistance test method by the GR 4007 standard can be measured by strength, so it is possible to evaluate the resistance of the permeable block through this test method. CONCLUSIONS : The abrasion resistance test and freeze-thaw resistance test can contribute to the improvement of the permeable block when added to the current quality evaluation tests.

PURPOSES : In this study, a numerical clogging model that can be used to realistically visualize the movement of particles in cylindrical permeability test equipment was proposed based on the system coupling of computational fluid dynamics with the discrete element method and experimental permeability test results. This model can also be used to simulate the interaction of dust particles with bedding particles. METHODS: A 4-way system coupling method with multiphase volumes of the fluid model and porous media model was proposed. The proposed model needs to consider the influence of flow on the dust particles, interaction between the dust particles, and interaction between the dust particles and bedding layer particles. The permeability coefficient of the bedding layer in cylindrical permeability test equipment was not calculated by using the permeability test result, but was estimated by using the particle packing model and Ergun model. RESULTS : The numerical simulation demonstrated a good agreement with the experimental test results in terms of permeability and drain time. Additionally, the initial movement of particles due to the sudden drain hole opening was successfully captured by the numerical model. CONCLUSIONS : A 4-way coupling model was sufficient to simulate the water flow and particle movement in cylindrical permeability test equipment. However, additional tests and simulation are required to utilize the model for more realistic block pavement systems.

L-carnitine은 라이신과 메티오닌으로 생합성되며 골격근 과 심근을 포함한 다양한 동물조직에서 발견된다. L-carnitine이 포함된 식품으로는 양고기, 소고기, 돼지고기 등이 있고 근육발달에 도움을 주며 뼈를 강화하거나 대사작용을 도와주는 기능을 하여 영양 보조제로 많이 섭취하는 것으로 알려져 있다. 최근 L-carnitine은 제 2형 당뇨병, 골다 공증, 대사성 신경증후군 등의 다양한 질병의 약물로도 연구 되고 있으며 암에서는 치료 보조제로 개발되어있다. 하지만 대장암에서의 L-carnitine에 대한 효과 및 기전에 대해서는 명확하지 않고 연구된 바가 없기 때문에 본 연구에서 저자들은 L-carnitine의 효능을 인간대장암세포주 HCT116에서 규명하고자 하였다. L-carnitine은 세포 내 활성산소종 (ROS)를 높은 수준으로 증가시켜 세포 증식을 억제하였다. 또한, 세포 증식과 죽음에 관련한 단백질 ERK1/2와 p38을 유의적으로 활성화 시킨다는 것을 입증 하였다. 이때, ERK1/2 억제제(PD98059)를 처치하여 ERK1/ 2의 활성화가 활성산소종 발생 및 세포사멸에 중요하다는 것을 밝혔다. 따라서, 본 연구 결과는 L-carnitine이 대장 암세포주의 증식을 억제 할 수 있고 이는 대장암의 치료에 있어 잠재적인 치료 물질이 될 수 있음을 시사하며 이 과정에 관여하는 신호전달기전을 조사하여 항암의 치료기 전에서 활성산소종이나 ERK1/2, p38 단백질의 활성화의 중요성을 제시하였다.

이 연구는 식품 중 잔류농약에 대한 국내 모니터링 프로그램의 전반적인 현황을 이해하기 위해 수행되었으며 더 나아가 개선이 필요한 사항이 제안되었다. 이 연구로 부터 국내 잔류농약 모니터링 프로그램 현황은 다음과 같이 요약될 수 있었다. 국내에서는 식품의약품안전처가 잔류농약 모니터링을 총괄한다. 그리고 모니터링 시점(유통 또는 생산단계에서 시료수집)에 따라 모니터링 책임 기관이 다른데, 유통단계의 식품에 대해서는 식품의약품안전처, 지방식품의약품안전청, 지방자치단체가, 생산단계에서는 국립농산물품질관리원(NAQS)과 지방자치단체가 모니터링을 실시한다(부분적으로 판매와 유통단계에서도 실시). 국내의 모니터링 프로그램을 목적에 따라 구분하면 위해평가 모니터링(monitoring for risk assessment)으로 MFDS의 “잔류실태조사”와 NAQS의 “국가잔류조사”가 있고, 지방 식품의약품안전청과 지방자치단체에서는 주로 규제 모니터 링(monitoring for regulation)을 실시하고 있었다. 수입식품의 경우 통관단계(지방식품의약품안전청 책임)와 유통단계 모두에서 모니터링이 실시되어야 한다. 유통단계 수입식품 모니터링은 MFDS, 지방식품의약품안전청, 지방자치단체가 담당하고 있는 데 아직 체계적이고 지속적인 국가수준의 모니터링 프로그램이 실시되고 있지 않는 것으로 보인다. 국내 잔류농약 모니터링 프로그램과 관련하여 앞에서 기 술한 내용과 더 상세한 내용을 토대로 모니터링 프로그램의 개선을 위해 i) 모니터링 프로그램의 목적에 대한 명확성 제고, ii) 수입식품에 대한 모니터링 프로그램의 강화 iii) 일반국민에게 모니터링 결과의 공개(연간보고서와 데이터베이스 발간)를 제안하였다. 식품의 안전성을 확보고 시행하기 시작한 농약 허용물질목록 관리제도(positive list system, PLS)가 성공을 거두기 위해서는 잔류농약 모니터링 프로그램에 대한 철저한 검토와 개선을 위한 노력이 필요한 것으로 생각된다.

Batch adsorption tests were performed to evaluate the applicability of adsorption kinetic model by using hydrogel chitosan bead crosslinked with glutaraldehyde (HCB-G) for Cu(II) as cation and/or phosphate as anion. Pseudo first and second order model were applied to determine the sorption kinetic property and intraparticle and Boyd equation were used to predict the diffusion of Cu(II) and phosphate at pore and boundary-layer, respectively. According to the value of theoretical and experimental uptake of Cu(II) and phosphate, pseudo second order is more suitable. On comparison with the value of adsorption rate constant (k), phosphate kinetic was 2-4 times faster than that of Cu(II) at any experimental condition indicating the electrostatic interaction between NH3 + and phosphate is dominated at the presence of single component. However, when Cu(II) and phosphate simultaneously exist, the value of k for phosphate was sharply decreased and then the difference was not significant. Both diffusion models confirmed that the sorption rate was controlled by film mass transfer at the beginning time (t < 3 hr) and pore diffusion at next time section (t > 6 hr).

The objective of this study was to establish an in vitro culture system for ovarian preantral follicles of B6D2F1. First, we optimized the in vitro preantral-follicle culture by culture duration, follicle stimulating hormone (FSH) type, and activin A concentration. Duration of in vitro culture for 9, 11, and 13 days was sufficient for the normal development of preantral follicles to antral follicles. Formation of cumulus cell–oocyte complex (COC) was induced by treatment with human chorionic gonadotropin (hCG; 2.5 IU/mL) and epidermal growth factor (EGF; 5 ng/mL). In addition, metaphase II (MII) oocytes formed during this in vitro culture of preantral follicles. In vitro preantral-follicle culture for 9 days showed higher rates of growth and maturation, thus yielding a greater number of antral follicles, and there were significant differences (p < 0.05) in the number of MII oocytes (that formed from these preantral follicles via differentiation) between the 9-day culture and 11-day or 13-day culture. The follicles cultured for 9 days contained a tightly packed well-defined COC, whereas in follicles cultured for 11 days, the COC was not well defined (spreading was observed in the culture dish); the follicles cultured for 13 days disintegrated and released the oocyte. Second, we compared the growth of the preantral follicles in vitro in the presence of various FSH types. There were no significant differences in the growth and maturation rates and in differentiation into MII oocytes during in vitro culture between preantral follicles supplemented with FSH from Merck and those supplemented with FSH from Sigma. To increase the efficiency of MII oocyte formation, the preantral follicles were cultured at different activin A concentrations (0 to 200 ng/mL). The control follicles, which were not treated with activin A, showed the highest rate of differentiation into antral follicles and into MII oocytes among all the groups (0 to 200 ng/mL). Therefore, activin A (50 to 200 ng/mL) had a negative effect on oocyte maturation. Thus, in this study, we propose an in vitro system of preantral-follicle culture that can serve as a therapeutic strategy for fertility preservation of human oocytes for assisted reproductive medicine, for conservation of endangered species, and for creation of superior breeds.

The aim of this study was to investigate effects of hyaluronidase during IVM on oocyte maturation, oxidative stress status, expression of cumulus expansion-related (PTX, pentraxin; GJA1, gap junction protein alpha 1; PTGS2, prostaglandin-endoperoxide synthase 2) and fatty acid metabolism-related (FADS1, delta-6 desaturase; FADS2, delta-5 desaturase; PPARα, peroxisome proliferator-activated receptor-alpha) mRNA, and embryonic development of porcine oocytes. The cumulus-oocyte complexes (COCs) were incubated with 0.1 mg/mL hyaluronidase for 44 h. Cumulus expansion was measured at 22 h after maturation. At 44 h after maturation, nuclear maturation, intracellular glutathione (GSH) and reactive oxygen species (ROS) levels were measured. Gene expression in cumulus cells was analyzed using real time PCR. The cleavage rate and blastocyst formation were evaluated at Day 2 and 7 after insemination. In results, expansion of cumulus cells was suppressed by treatment of hyaluronidase at 22 h after maturation. Intracellular GSH level was reduced by hyaluronidase treatment (p < 0.05). On the other hand, hyaluronidase increased ROS levels in oocytes (p < 0.05). Only PTGS2 mRNA was enhanced in COCs by hyaluronidase (p < 0.05). Population of oocytes reached at metaphase II stage was higher in control group than hyaluronidase treated group (p < 0.05). Both of cleavage rate and blastocyst formation were higher in control group than hyaluronidase group (p < 0.05). Our present results showed that developmental competence of porcine oocytes could be reduce by hyaluronidase via inducing oxidative stress during maturation process and it might be associated with prostaglandin synthesis. Therefore, we suggest that suppression of cumulus expansion of COCs could induce oxidative stress and decrease nuclear maturation via reduction of GSH synthesis and it caused to decrease developmental competence of mammalian oocytes.

A typical Mathematics class is comprised of a heterogeneous group of students in terms of academic ability, learning styles, intelligence quotient, home background and the likes. The inability of the teachers to effectively manage these differences usually leads to poor academic achievement among the learners, especially the weak ones. This study therefore determined the effectiveness of Cooperative Learning Technique on low learning ability students in Mathematics. Quasi-experimental research design was adopted. The sample size purposively selected consisted of 137 students from four schools in Education District II and IV, Lagos State, Nigeria. Two hypotheses were raised and tested at 0.05 level of significance. The collected data were analyzed using t-test. The result of the analysis revealed that cooperative learning strategy enhanced the low ability students’ achievement in Mathematics. Also, cooperative learning strategy enhanced low learning abilities students in understanding mathematics irrespective of their gender. It is therefore, recommended that teachers should adopt the cooperative learning strategy to teach Mathematics. For teachers to be more conversant with the use of cooperative learning strategy, as well as other interactive methods of teaching mathematics, workshops and conferences should be organized for secondary schools on the use of different methods of teaching learners from different ability levels, especially cooperative learning strategy.

A smart connective control system was invented recently for coupling control of adjacent buildings. Previous studies on this topic focused on development of control algorithm for the smart connective control system and design method of control device. Usually, a smart control devices are applied to building structures after structural design. However, because structural characteristics of building structure with control devices changes, a iterative design is required for optimal design. To defeat this problem, an integrated optimal design method for a smart connective control system and connected buildings was proposed. For this purpose, an artificial seismic load was generated for control performance evaluation of the smart coupling control system. 20-story and 12-story adjacent buildings were used as example structures and an MR (magnetorheological) damper was used as a smart control device to connect adjacent two buildings. NSGA-II was used for multi-objective integrated optimization of structure-smart control device. Numerical simulation results show the integrated optimal design method proposed in this study can provide various optimal designs for smart connective control system and connected buildings presenting good control performance.

본 논문은 한국의 독도영유권의 역사와 수호전략을 분석하기 위한 것이다. 이를 위해 신라·고려·조선·대한제국의 독도통치, 일제의 독도침탈과 미군정기의 독도영유권 회복, 일본의 독도도발과 한국의 실효적 지배, 독도문제의 국제정치적 함의와 한국의 독도수호전략을 살펴본 후 결론을 도출해본 것이다. 신라 이사부가 우산국(현 울릉도와 독도)을 정벌한 이래 오랫동안 우리민족은 독도를 통치해왔다. 그러다가 일제는 1905년 러일전쟁 중 한반도 침탈과정에서 한국영토 독도를 일본영토로 강제 편입했다. 제2차 세계대전의 전범국 일제의 패망이후 우리는 독도 를 수호하여 실효적으로 지배해왔다. 하지만 일본은 전후 일본질서를 규정한 샌프란시스코조약에서 한국에의 반환도서로 독도가 명기되지 않았다는 이유로 독도의 일본영유권을 제기하고 있다. 일본은 독일이 포츠담협정을 통해 강제합병한 모든 영토를 말끔히 반환한 것과는 대조를 보이고 있다. 일본군 무장해제라는 빌미로 제2차 세계대전 전범국 과는 거리가 먼 한국이 일본 대신 분단되어 고통 받고 있는 현실을 직시하여, 일본은 더 이상 독도도발을 해서는 안 될 것이다. 한국은 외교 적·군사적 대응역량 강화를 통해 우리 영토 독도를 착실히 수호·개발해 나가야 할 것이다.

본 연구는 중부권역에서 발생한 산사태를 중심으로 수량화이론을 이용하여 산림환경인자가 발생면적에 미치는 영향 분석을 통해 예방적인 측면에서 산사태 발생 위험성에 대한 예측기준을 작성하였 다. 산사태 재해로 발생면적에 영향을 미치는 각 인자의 기여도는 토심(0.3606)이 가장 높았으며, 다음으로 고도(0.2065), 종단사면(0.2065), 경사(0.1297), 사면방위 0.1154)순으로 높게 나타났다. 산사태 발생 위험 기여도가 높은 6개 인자의 category별 상대점수 범위는 0점에서 1.5122점 사이에 분포하고 있었고 중앙값은 0.7561점이었다. 이 점수를 기준으로 산사태 발생 위험성을 4개 등급으로 구분한 예측 판정표를 작성하였다. Ⅰ등급의 점수는 1.1343 이상, Ⅱ등급은 0.7562~1.1342, Ⅲ등급 은 0.3782~0.7561, IV등급은 0.3781 이하로 나타나 1등급, 2등급, 3등급에서 산사태 발생 비율이 96%로서 비교적 높은 적중률을 보였다. 따라서 본 판정표는 중부권역의 위험 비탈면에 있어서 산사 태 발생 위험도 판정에 유용하게 활용할 수 있을 것으로 판단된다.