In this paper, nitrogen-doped reduced graphene oxide(rGO) is obtained by thermal annealing of nitrogen-containing compounds and graphene oxide (GO) manufactured by modified Hummers' method. We use melamine as a nitrogen-containing compound and treat GO thermally with melamine at over 800 ~ 1,000℃ and 1 ~ 3 hr under Ar atmosphere. The electrical conductivity of doped rGO is measured by 4-point probe method. As a result, nitrogen contents on rGO are found to be in the range of 2.5 to 12.5 at% depending on the doping conditions after thermal annealing. The main doping site on graphene oxide is changed from pyridinic-N and pyrrolinic N to the graphitic site as the heat treatment temperature increases. The electrical conductivity of doped rGO increases as the N doping content increases. As the thermal treatment time increases, the change of both total doping contents and doping sites is slight and the surface resistance is remarkably reduced, which is caused by healing effects of doped graphene oxide at high temperature.

We conducted a survey of open clusters within 1 kpc from the Sun using the astrometric and photometric data of the Gaia Data Release 2. We found 655 cluster candidates by visual inspection of the stellar distributions in proper motion space and spatial distributions in l 􀀀 b space. All of the 655 cluster candidates have a well dened main-sequence except for two candidates if we consider that the main sequence of very young clusters is somewhat broad due to dierential extinction. Cross-matching of our 653 open clusters with known open clusters in various catalogs resulted in 207 new open clusters. We present the physical properties of the newly discovered open clusters. The majority of the newly discovered open clusters are of young to intermediate age and have less than 50 member stars.

본 연구는 새만금 간척지에서 방풍시설의 설치에 따른 수림대의 초기 생존율을 분석하기 위하여 생존 분석 기법 중의 하나인 생명표법을 적용하였다. 생명표법은 의학, 사회과학 등 많은 분야에서 활용하고 있는 방법 이며, 본 연구에서는 방풍책의 설치에 따른 초기 수림대 수목의 생존 기간별 생존율, 중위 시간 등을 생명표 를 통해 알아보고, 생존함수 그래프와 위험함수 그래프 그리고 수림대별 비교를 통해 생존율의 차이를 분석 하고자 하였다. 주요 결과로는 곰솔 수림대의 중위 시간은 100% P-tb와 25% P-tb에서는 48.00개월 이었 고, 50% P-tb는 20.85개월로 짧았다. 25% P-tb에서 누적 생존율이 가장 높았으며, 위험률은 50% P-tb가 가장 높았다. 졸참나무 수림대의 경우 모든 수림대에서 중위 시간은 48.00개월 이었으며, 50% P-tb에서 누 적 생존율이 가장 높았고, 위험률은 100% P-tb에서 가장 높았다. 생존율 비교 결과, 곰솔 수림대는 전체적 으로 방풍책의 설치가 생존율에 영향을 미쳤으며, 특히 50% P-tb와 25% P-tb에서 유의미한 차이가 나타났 는데, 25% P-tb가 생존율과 위험률 측면에서 우수한 결과를 나타내었다. 반면에 졸참나무 수림대의 경우 전 체 수림대의 생존율이나 수림대별 생존율은 방풍책의 설치에 영향을 받지 않는 것으로 분석되었다.

The current study examined the validity of classroom-based English assessment in the elementary school context using a validity analysis framework, which includes cognitive, instructional, and inferential validity components. As a case study, it evaluated two unit achievement tests administered to 142 6th grade students. Three types of data (i.e., the curricular learning goals, instructional contents covered for the two units, and two unit achievement tests and scores) were collected and analyzed for the classroom-based assessment validity argument. Results revealed that the two tests were relevant to the curriculum and instruction; however, there was a lack of correspondence between the two tests and the curriculum (cognitive validity); moreover, the instructional contents were not sufficiently covered with representative test items (instructional validity). While the test items functioned as expected, students showed a wide range of achievement, which was not expected in the achievement test context (inferential validity). The findings suggest implications for the development and use of classroom-based assessment for young language learners.

This study was conducted to analyze the specific genes associated with sex-determination in Korean native cow. The highly organized spermatogenesis requires accurate spatial and temporal regulation of gene expression, which is governed by transcriptional, post-transcriptional, and epigenetic processes. Recently, farmers have been interested in determining the sexual identity of the calves in their farm. We analyzed the sperm of Korean native and Holstein cows, which were supplied from Hanwoo Improvement Center. We evaluated sperm motility and expression of sperm-specific genes after treating semen with both male- and female reagents. Sperm motility in Korean native cows decreased by approximately 10% in the first 30 minutes after treatment with sex-determination reagent. However, sperm motility of Holstein cows decreased to 60-70% after 15 minutes and to 20-30% after 30 minutes. We selected six specific genes expressing in the spermatozoa to analysis the gene expression level. The Real-time PCR results suggest that the selected genes (Gimap4, Tmeff1, Rac2, Abi2, Rac1, and Clu) were highly expressed in the group treated with the male reagent compared to the group treated the female reagent and to the untreated-group (control). In the present study, we suggest that the selected genes play a pivotal role in sex-determination.

The kidney is a highly complex organ, and acute or chronic renal diseases can occur with various complications such as diabetes and hypertension. So far, no target specific treatment is available in acute or chronic renal failure, necessitating the development of alternative therapeutic strategy. Recent experimental findings suggest that the renal function and structure can be restored after being treated with various sources of stem/progenitor cells. In this review, we discuss up-to-date findings of the potential of renal progenitor/stem cells in alleviating renal injuries with a focus on preclinical studies. We also review cellular mechanisms underlying the therapeutic function of these cells.

본 논문은 보편적으로 복잡한 문제로 정의되던 테트리스 게임을 강화학습을 통해 해결하기 위한 아키텍처를 구현하였다. 테트리스 게임은 무작위로 나타나는 블록의 모양과 회전의 형태를 고려해서 블록을 최적의 위치에 신속하게 쌓아야 하므로, actor의 빠른 판단능력과 반응속도를 요구한다. 또한, 다양한 블록의 형태와 순서로 인해 매우 많은 경우의 수가 나타나기 때문에 수행의 주체가 사람이라면 단순히 기억력과 암기에 의존하는 방법으로는 수행에 한계가 있다. 따라서 본 연구에서 구현한 강화학습 아키텍처의 경우 학습 모델의 구현뿐 아니라 의사결정의 정확성을 높일 수 있는 휴리스틱을 보상에 가중치로 활용하는 방식으로 접목하였고, 그 결과 사람이 직접 게임을 수행하는 것에 비해 보편적으로 높은 점수를 얻을 수 있었다. 아직은 해당 분야를 완전히 정복하였다고 표현할 수는 없지만, 여러 번의 실험에서도 일반적인 사람에 비해서 더욱 좋은 플레이를 할 수 있었다. 하지만 성능에 가장 큰 영향을 미치는 요소가 학습 모델보다 휴리스틱에서 비롯되고 있다는 단점도 식별하였다. 이에 본 논문에서는 이러한 아키텍처의 구조와 사용한 기술들과 알고리즘에 대해 자세히 기술하였으며 접근 방향을 제시한다.

This study investigated the effects of negotiation in the process of providing written corrective feedback (WCF) by comparing three different patterns: non-negotiation, minimal negotiation, and extended negotiation. The data were collected from three intermediate academic English classes at a university in Korea. Each class was exposed to different degrees of negotiation while they received WCF for two target forms, the past verb forms and the English articles, in their written production (text re-construction tasks). Their accuracy improvement was measured by text-reconstruction writing tasks and error correction tests. The study found that the use of negotiation affected accuracy improvement of the target forms; however, its effectiveness varied depending on the target forms and measurements. For the past tense, negotiation, regardless of its amount, resulted in more accuracy improvement than non-negotiation in both text re-construction tasks and error correction tests. However, for the English articles, negotiation operated differently: extended negotiation significantly brought about more accuracy development in both measurements, but the difference between minimal negotiation and non-negotiation was only observed in the error correction test, not in the text re-construction task.

목적: 이 연구는 안경과 선글라스에서 테와 렌즈의 형태와 색상에 대한 한국인과 중국인 소비자 집단의 선호도 차이를 조사하기 위하여 실시되었다. 방법: 한국에 유학 중인 중국인 학생 150명과 한국인 대학생 150명을 대상으로 설문조사를 실시하고 그 결과를 분석하였다. 안경광학 관련 전공자는 설문 대상에서 배제되었다. 중국인 학생들에게는 중국어 간체자로 번역된 설문지를 제공하였으며, 제공된 설문지는 한국 대학 석사과정에 유학 중인 중국인 원어민 학생이 한국어 설문지를 바탕으로 번역한 것이다. 결과: 중국인 소비자 집단은 안경보다 선글라스에서 글로벌 유명 브랜드를 더 선호하였으며, 한국산 안경 제품을 상대적으로 선호하는 것으로 나타났다. 또한, 무테 또는 반무테, 금색테, 투톤컬러 렌즈 항목에서 한국인 소비자 집단보다 높은 선호도를 나타냈다. 결론: 이 연구의 결과는 한국 안경 제조․유통 업체의 중국 시장 진출이나 중국인 고객 비율이 높은 안경원 의 판매 전략 수립에 기여할 수 있을 것으로 기대된다.

The study investigated the effects of recasts and prompts on learning language forms that arose incidentally in dyadic interaction, focusing on the degree of explicitness of each type of feedback and learner proficiency levels. The data were collected from 64 beginning and upper-intermediate English learners of Korean. Thirty-one beginning learners were randomly assigned to a feedback group and to a control group, and thirtythree upper-intermediate learners were also assigned to a feedback group and to a control group. Each learner was paired with an English speaker and worked on a picture-sequencing task. The learners in the feedback groups received recasts or prompts on their erroneous utterances while the learners in the control groups did not. The effects of feedback were measured by pre-interaction picture descriptions and immediate and delayed post-interaction correction tasks. The study found that both recasts and prompts had some effects on learning the targeted forms, and more explicit forms of each feedback resulted in a higher rate of correction. The beginning learners took more advantages of recasts relative to the upper-intermediate learners, and explicit prompts worked better for the upper-intermediate learners. The effects of prompts sustained longer than recasts in both levels.

Acute kidney injury (AKI) is a disorder that is manifested by a sudden decrease of renal function within several hours, and AKI remains a significant cause that can lead to increasing morbidity and mortality. Although AKI has been extensively studies in animal models, translating the results from animal studies into clinical use has not been successful due to various factors including basal etiology of kidney deficiency and comorbidities and the complexity of this pathology. As a golden parameter, measuring serum creatinine (SCr) and blood urea nitrogen (BUN) has been conventionally used for determining the renal function, however, these biomarkers has been regarded suboptimal to identify renal injuries in early stages. In this study, we attempted to screen other serum biomarkers in early AKI event using cynomolgus monkeys. Two male monkeys, aged 60 months, were subjected to ischemic injury by unilateral clamping of renal pedicles for forty five minutes and then subsequently reperfused; the unclamped kidney was regarded as non-injured controls. Compared with control kidneys, we have found that the concentration of several inflammatory proteins including MCP1, TGFα, GSTα, were higher in the renal vein of injured kidney compared with control side after 24 and 48 hours of AKI. However, changes of serum level of KIM-1, which is one of the most-widely studied marker in rodent studies, were not different after AKI. Our results provide an useful information while developing a novel marker in AKI.

Cryopreservation of bovine embryos is used to efficiently implant surrogate mothers. It has been widely accepted that high lipid content in the oocyte interrupts its survival during freeze-thaw cycles. Serum component in the culture medium is thought to increase the embryo`s lipid contents. Conversely, L-carnitine stimulates lipid metabolism by transporting long chain fatty acids into the mitochondria. Objective of this study was to analyze the effect of L-carnitine supplementation in IVM medium and defined IVC medium on the development, lipid contents and the cryosurvival of bovine IVF embryos. 0.0, 1.5, 3.0 and 6.0 mM L-carnitine was supplemented in IVM medium, respectively (IVM-LC 0.0, LC 1.5, LC 3.0 and LC 6.0). Development rate from the 2cell to the morula stages was higher in IVM-LC 3.0 groups than those of IVM-LC 6.0 (p<0.05). But there were no significant differences among the other groups in the blastocyst rates and lipid content results. When 0.0, 1.5, 3.0 and 6.0 mM L-carnitine were supplemented in IVC medium (IVC-LC 0.0, LC 1.5, LC 3.0 and LC 6.0), development competence was not significantly different between those embryos. Lipid contents of embryos treated L-carnitine (IVC-LC 1.5, 3.0 and 6.0) were significantly lower than embryos of non-treated group. L-carnitine was supplemented 0.0, 1.5, 3.0, 6.0 mM during IVM and 3.0 mM during IVC (LC 0.0 - 3.0, LC 1.5 – 3.0, LC 3.0 – 3.0, LC 6.0 – 3.0) and cryosurvival of blastocysts confirmed after freezing-thawing. There were no significant differences on development, but LC 3.0 – 3.0 was significantly lower lipid contents than other groups. And LC 3.0 – 3.0 had better survival rates and hatched rates of blastocysts than LC 0.0 – 0.0. In conclusion, supplementation of L-carnitine in defined IVC medium decreases lipid contents. And L-carnitine supplementation improves cryosurvival and developmental ability of bovine IVF embryos.

The early-onset familial Alzheimer's disease (EOFAD/ FAD), the less common type of Alzheimer's disease (AD) currently affects a vast number of individuals worldwide. This type is being inherited as an autosomal dominant fashion. Missense mutations on Amyloid precursor protein (APP) and Presenilins 1 and 2 (PSEN1 & PSEN2) are known as major genetic factors in FAD. Conversely, missense mutations on microtubule-associated protein tau (MAPT) are also thought to involve. Up to date, several triple-transgenic animal models with muted forms of the human APP, PSENs and MAPT have been reported. Compared to other animals, canines are more emotional and their disease signs can be easily diagnosed. This attempt was to develop a triple transgenic canine model for the AD. We have obtained the coding sequences of APP, PSEN1 and MAPT from Dana-Farber/Harvard Cancer Center DNA resource core at HMS and incorporated several common AD mutations. The transgenic construct is composed of hNSE (ENO2) promoter-driven three AD genes fused together with modified 2A sequences. It was transfected into the canine fetal fibroblasts which were then used to perform somatic cell nuclear transfer (SCNT). The viable transgenic embryos were obtained after in vitro culture and the GFP was detected. In this study, we have successfully produced viable triple transgenic canine cloned embryos using SCNT technique. These transgenic canine embryos will be further developed into canines with FAD. The transgenic canines will be a good candidate in the AD research field.