Spermatogonial stem cells are self-renewal and differentiate into sperm in post-pubertal mammals. There exists a balance between the self-renewal and differentiation in the testes. Spermatogonial stem cells make up only 0.03% of testicular cells in adult mice. These cells maintain sperm production by differentiating after puberty. Therefore, analyzing the expression of genes associated with spermatogenesis is critical for understanding differentiation. The present study aimed to establish the postnatal period of cells in relation to spermatogenesis. To study the expression of differentiated and undifferentiated marker genes in enriched spermatogonial stem cells, in vitro culture was performed and cells from pup (6–8-day-old) and adult (4-months-old) testicular tissues were isolated. As a result, undifferentiated genes, Pax7, Plzf, GFRa1, Etv5 and Bcl6b , were highly increased in cultured spermaotogonial stem cells compared with pup and adult testicular cells. On the other hands, differentiated gene, c-kit was highly increased in adult testicular cells, Also Stra8 gene was highly increased in pup and adult testicular cells. This study provides a better understanding of spermatogenesis-associated gene expression during postnatal periods.

Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.

L-ascorbic acid (L-AA; vitamin C) induces apoptosis in cancer cells. This study aimed to elucidate the molecular mechanisms of L-AA-induced apoptosis in human laryngeal epidermoid carcinoma Hep-2 cells. L-AA suppressed the viability of Hep-2 cells and induced apoptosis, as shown by the cleavage and condensation of nuclear chromatin and increased number of Annexin V-positive cells. L-AA decreased Bcl-2 protein expression but upregulated Bax protein levels. In addition, cytochrome c release from the mitochondria into the cytosol and activation of caspase-9, -8, and -3 were enhanced by L-AA treatment. Furthermore, apoptosis-inducing factor (AIF) and endonuclease G (EndoG) were translocated into the nucleus during apoptosis of L-AA-treated Hep-2 cells. L-AA effectively inhibited the constitutive nuclear factor-κB (NF-κB) activation and attenuated the nuclear expression of the p65 subunit of NF-κB. Interestingly, L-AA treatment of Hep-2 cells markedly activated Akt and mitogen-activated protein kinase (MAPK; extracellular signal-regulated kinase 1/2, p38, and c-Jun N-terminal kinase [JNK]) and and LY294002 (Akt inhibitor), SB203580 (p38 inhibitor) or SP600125 (a JNK inhibitor) decreased the levels of Annexin V-positive cells. These results suggested that L-AA induces the apoptosis of Hep-2 cells via the nuclear translocation of AIF and EndoG by modulating the Bcl- 2 family and MAPK/Akt signaling pathways.

Calcium is the most abundant stored mineral in the human body and is especially vital for bone health; thus, calcium deficiency can cause bone-related diseases, such as osteopenia and osteoporosis. However, a high concentration of serum calcium, which is commonly known as hypercalcemia, can also lead to weakened bones and, in severe cases, osteosarcoma. Therefore, it is necessary to maintain the concentration of calcium that is appropriate for bone biology. In the present study, we aimed to elucidate the effects of high concentration of calcium, approximately 2 folds the normal calcium level, on osteoblast differentiation. The CaCl2 treatment showed dose-dependent suppression of the alkaline phosphatase activity and mineralized nodule formation. Calcium showed cytotoxicity at an extremely high concentration, but a moderately high concentration of calcium that results in inhibitory effects to osteoblast differentiation showed no signs of cytotoxicity. We also confirmed that the CaCl2 treatment repressed the mRNA expression and protein abundance of various osteogenic genes and transcriptional factors. Considered together, these results indicate that a high concentration of calcium negatively regulates the osteoblast differentiation of C2C12 cells.

We report the discovery of a giant exoplanet in the microlensing event OGLE-2017-BLG-1049, with a planet―host star mass ratio of q = 9.53 ± 0.39 × 10-3 and a caustic crossing feature in Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of θE = 0.52 ± 0.11 mas. However, the microlens parallax is not measured because the time scale of the event, tE ≃ 29 days, is too short. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. We find that the lens system has a star with mass Mh = 0.55+0.36 -0.29 M⊙ hosting a giant planet with Mp = 5.53+3.62 -2.87 MJup, at a distance of DL = 5.67+1.11 -1.52 kpc. The projected star{planet separation is aㅗ = 3.92+1.10 -1.32 au. This means that the planet is located beyond the snow line of the host. The relative lens{source proper motion is μrel ~ 7 mas yr-1, thus the lens and source will be separated from each other within 10 years. After this, it will be possible to measure the flux of the host star with 30 meter class telescopes and to determine its mass.

이 논문은 예이츠의 희곡 『큰 시계탑의 왕』의 타이틀 롤을 맡고 있는 큰 시계탑의 왕에 관한 연구이다. 『큰 시계탑의 왕』은 수정과 발전을 거듭하는 과정에서 극의 제목이 『삼월의 보름달』로 바뀌게 되고, 새로운 제목의 버전에서는 원래 버전에서 타이틀 롤인 왕은 사라지게 되었다. 하지만 새로운 버전에서 그 인물이 생략되었다는 것이 원래 버전에서 담당하고 있던 인물의 기능을 모두 무의미한 것으로 평가하는 것은 아니기 때문에, 이 논문은 큰 시계탑의 왕에 주목하여 극을 면밀히 분석함으로써 그가 수행하고 있는 여러 기능을 탐구한다. 먼저 『큰 시계탑의 왕』이라는 제목이 암시해주는 것처럼 왕은 시간을 상징하는 인물이다. 하지만 이러한 상징적 의미뿐 아니라 이 희곡의 구조적 원형이 되고 있는 『매의 우물에서』의 노인과 같이 주인공과 대비되는 역할을 하고 있음을 증명하고, 더 나아가 극의 행위가 진행될 수 있도록 하는 촉발자와 극의 극적 긴장감을 조성하는 역할을 하고 있음을 보여준다. 결론으로서 왕의 존재가 이 희곡을 『삼월의 보름달』과 차별화하는 데 중요한 요소가 된다는 것을 주장한다.

The effects of supplementing ESP-FM (Erythrobactor sp.), freshwater Chlorella (Chlorella sp.), and baker’s yeast (Saccharomyces cerevisiae) on the nutritional value and mass production of Moina macrocopa, which is used as a live feed for fish fry production, was investigated. Consequently, the effects of feeding the enriched M. macrocopa to the nutritional composition of larval rockfish (Sebastes schlegel) and carp (Cyprinus carpio) was also investigated. Maximum density of M. macrocopa was reached within 15-21 days after inoculation (0.5 to 22 individual/mL), at various temperatures, and either decreased or remained almost constantly thereafter. Protein content and amino acids composition of M. macrocopa were found to be influenced by their respective diets while lipid and ash contents did not considerably change. M. macrocopa fed with baker’s yeast were low in n-3 HUFA content, and those fed on the freshwater chlorella were high in the 18:2n-6 and 18:3n-3 HUFA content, and in cultures treated with ESP-FM were high content in n-3 HUFA. The utilization of M. macrocopa as a substitute fish feed for carp and rockfish showed the enrichment nutritional content.

PURPOSES : The purpose of this study is to investigate the effects of urban road characteristics on temperature changes in urban areas using surface thermal temperature. METHODS : This study measured the surface thermal temperature of each road component from urban roads, analyzed the effect of the road component characteristics and vegetation on temperature, and estimated the regression models. RESULTS : As a result, the mean temperature was 27.3 ℃ on the roadway, 25.5 ℃ on the vegetated median, and 22.9 ℃ on the sidewalks. The roadside temperature was 26.14 ℃ with surrounding buildings and 23.82 ℃ near green spaces. The temperature with street trees was lower (24.45 ℃) than without (28.38 ℃) while it was 23.96 ℃ with vegetated median and 25.64 ℃ without. The temperatures were lower (24.70 ℃) on the permeable surface than on the impermeable surface (28.38 ℃). Model estimates show that the temperature decreases by 0.007 ℃ with an increase of 1 m² green (permeable space) space and the temperature with buildings tends to be 1.729 ℃ higher than that with green space. As green space increases by 1 m², the temperature tends to decrease by 0.017 ℃ on the roadway and by 0.012 ℃ on the sidewalk. Shade effect models show that street trees with shade affect temperature reduction by -3.884 ℃ on roadways and -3.314 ℃ on sidewalks. CONCLUSIONS : The results of this study demonstrate the differing effects of road characteristics on temperature. The roadway is more sensitive than the sidewalk to temperature changes and roadside vegetation, ambient green space, and pavement permeability contribute to temperature reduction.

Hydrogen isotopes (i.e. deuterium and tritium) are supplied to the tokamak in the International Thermonuclear Experimental Reactor (ITER) fuel cycle. One important part of the ITER fuel cycle is the recycling of unused fuel back to the tokamak, as almost 99 % of fuel is unburned during fusion reaction. For this, cryogenic distillation has been used in the isotope separation system (ISS) of ITER, but this technique tends to be energy-intensive and to have low selectivity (typically below 1.5 at 24 K). Recently, efficient isotope separation by porous materials has been reported in the so-called quantum sieving process. Hence, in this study, hydrogen isotope adsorption behavior is studied using chemically stable ZIF-11. At low temperature (40 K ~ 70 K), the adsorption increases and the sorption hysteresis becomes stronger as the temperature increases to 70K. Molar ratio of deuterium to hydrogen based on the isotherms shows the highest (max. 14) ratio at 50 K, confirming the possibility of use as a potential isotope separation material.

A facile microwave assisted solvothermal process is designed for fabricating SnS nanoparticles decorated on graphene nanosheet, which used as visible light driven photocatalyst. Some typical characterization techniques such as XRD, FT-IR, SEM with EDX analysis, and TEM and BET analysis are used to analyse the physical characteristics of as-prepared samples. Spherical SnS nanoparticles are uniformly dispersed on the surface of graphene nanosheet due to ammonia, which can prevent the aggregation of graphene oxide. Meanwhile, microwave radiation provides fast energy that promotes the formation of spherical SnS nanoparticles within a short time. The visible light photocatalytic activity of as-prepared SnS-GR nanocomposites is analysed through photodegradation efficiency of methylene blue with high concentration. According to the higher photocatalytic property, the as-prepared SnS-GR nanocomposites can be expected to be an efficient visible light driven photocatalyst. After five cycles for decolorization, the rate decreases from 87 % to 78 % (about 9 %). It is obvious that the photocatalytic activity of SnS-GR nanocomposite has good repeatability.

An important property of glass and ceramic solid waste forms is processability. Tellurite materials with low melting temperatures and high halite solubilities have potential as solid waste forms. Crystalline TiTe3O8 was synthesized through a solid-state reaction between stoichiometric amounts of TiO2 and TeO2 powder. The resultant TiTe3O8 crystal had a three-dimensional (3D) structure consisting of TiO6 octahedra and asymmetric TeO4 seesaw moiety groups. The melting temperature of the TiTe3O8 powder was 820℃, and the constituent TeO2 began to evaporate selectively from TiTe3O8 above around 840℃. The leaching rate, as determined using the modified American Society of Testing and Materials static leach test method, of Ti in the TiTe3O8 crystal was less than the order of 10-4 g·m-2·d-1 at 90℃ for durations of 14 d over a pH range of 2-12. The chemical durability of the TiTe3O8 crystal, even under highly acidic and alkaline conditions, was comparable to that of other well-known Ti-based solid waste forms.

충청북도농업기술원에서는 분홍색의 향기가 있고, Dendrobium kingianum에 비해 왜성종이며, 2월 하순경 개화하는 덴드로비 움 ‘리틀핑크’(D. kingianum ‘Little Pink’)를 육성하였다. 신품종 ‘리틀핑크’는 2007년 D. kingianum을 모본으로, D. kingianum var. silcockii를 부본으로 교배하였다. 종자 발아, 재배, 선발, 특성검정은 2008년부터 2015년까지 진행되었다. 생육이 좋고 꽃의 색, 모양이 우수한 계통을 선발한 후, 2016년부터 2018년까 지 3년에 걸쳐 국립종자원 신품종 심사기준으로 특성검정 결과, 우수성이 인정되어 2019년 최종 선발하여 ‘리틀핑크’로 명명하 였다. 주요 특성은 다음과 같다. 화색은 분홍색으로 Red-purple Group 72B(RHS color chart)이며, 향기가 있고 꽃잎무늬는 농담 무늬이다. 식물체 크기는 7.3cm로 대조품종 D. kingianum 23.5cm에 비해 작은 왜성종이다. 엽의 폭은 1.2cm이고, 꽃의 넓이는 2.4cm이다. 소화수는 3.7개이고 전반적으로 화분의 볼 륨감이 좋은 편이다. 꽃자루 길이는 7 .2cm로 대조품종 D. kingianum에 비해 짧다. 개화기는 2월 하순이며, 개화기간은 30일 정도이다.

이 연구는 스마트 온실의 온습도 데이터를 수집하고, 그 환 경 요인들 간의 상관관계를 분석하여 스마트 온실 환경관리의 기초자료를 제공하고자 수행되었다. 스마트팜 시스템이 도입된 토경 방식의 OS 온실과 암면 배지경 방식의 KB 온실을 대 상으로 기온, 근권온도, 상대습도의 항목에서 매일 24시간의 데이터를 수집하였고, 이중 최고와 최저, 일평균, 주간 평균, 야간 평균, 일교차의 여섯 가지로 세분하여 정리한 후 두 온실 간의 차이와 기온과 근권온도의 상관관계를 분석하였다. 장미의 생육적온은 주간, 야간, 일교차는 이며, 근권온도는, 습도 는 95% 미만을 유지하는 것이 좋다. 두 온실의 실제 환경과 장미의 적정 환경 조건을 비교했을 때, 주간 기온은 OS 온실 에서 5개월 간, KB 온실에서 7개월 간 적정 수준(24~27˚C)을 유지하였다. 야간 기온은 두 온실 모두 2개월간 적정 수준 (15~18˚C)을 유지하였고, 일교차는 OS 온실에서 6개월간, B 온실은 9개월 간 적정 수준(약 10˚C)에 근접하였다. 근권온도 는 OS 온실에서 10개월, KB 온실에서 5개월간 적정 수준 (20~25˚C)을 유지한 반면, 상대습도는 두 온실 모두 연중 적정 범위 내에 들었다. 기온과 근권온도의 상관관계를 분석한 결 과, OS 온실은 최고 온도, 평균 온도, 주간 온도, 야간온도에 서는 뚜렷한 상관관계를, 최저온도와 일교차에서는 약한 상관 관계를 보였으며, KB 온실에서는 전 영역에서 매우 강한 직선 적 비례 관계를 보였다. 결론적으로 토경재배를 실시하는 OS 온실이 고설식 암면배지경을 실시하는 KB 온실에 비해 근권 온도가 기온의 영향을 덜 받았으며, 완충능력이 높은 토경재 배에서는 기온의 영향을 덜 받는다고 볼 수 있다.

절화 국화 ‘백마’를 재배하고 있는 관행농가와 스마트팜의 시설현황, 재배환경, 절화생육 및 경영성과를 비교 분석하였 다. 관행농가는 비닐하우스에서 토경으로, 스마트팜은 유리온 실에서 양액재배하고 있었다. 스마트팜은 광량, 온도, 습도, CO2, 풍속, 강우, 양액 pH와 EC 측정을 위한 센서들을 갖추어 자동제어하고 있었으며, 실시간으로 컴퓨터와 휴대전화 어플 리케이션을 이용하여 온실을 관리하고 있었다. 반면에 관행농 가는 환경 측정용 센서와 관비재배용 pH와 EC 센서들이 전혀 없었고, 모든 시스템들을 수동으로 작동하고 있었다. 시설 내의 주간과 야간온도는 관행농가에서 생육 적온보다 낮게 관리되고 있었다. 관행농가의 토양 EC는 3.2dS･m-1로 높게 나타나 절화 생육에 적합하지 않은 것으로 나타났고, 스마트팜은 1.1dS･m-1 로 적절하게 관리하고 있었다. 재배방법에 있어서 토양소독은 관행농가에서는 실시하지 않았으며, 스마트팜에서는 과산화수 소를 이용하여 토양소독을 실시하고 있었다. 그 외에 재배방 법은 큰 차이가 없었으나, 관행농가에서 응애가 많이 발생하 여 피해증상이 나타났다. 절화장, 화폭, 생체중, 엽록소 함량 등과 같은 절화 생육은 관행농가보다 스마트팜에서 더 양호한 것으로 나타났다. 경영성과 측면에서 1,000m2 기준으로 순이 익은 관행농가에서 -419천원이었고, 스마트팜은 4,484천원이 었으며, 생산량과 수취가격이 관행농가보다 스마트팜에서 각 각 22%와 52% 더 높은 것으로 나타났다. 이와 같은 절화의 생육과 경영성과의 차이는 스마트팜의 자동화 설비에 의해 정 밀 생육관리가 가능했기 때문이라고 판단되었다.

본 연구는 스프레이 타입의 절화 장미가 재배되고 있는 호 남지역 스마트팜의 시설과 연중 재배환경을 분석하고, 그에 따른 외적 특성과 수명을 분석하고자 수행하였다. 본 연구에 서 선정한 스마트팜은 연동형 유리 온실로 CCTV를 통해 실시 간으로 농가 상황이 확인 가능하며, 1세대 스마트팜으로 조사 되었다. 스마트팜 시설 내 재배환경은 여름에 최고온도가 다 른 계절에 비해 높았고, 겨울에는 일적산광량이 최소 광요구 도에 미치지 못하는 것으로 나타났다. 또한, 상대습도는 겨울 과 가을에 유의적으로 높아 겨울의 VPD는 0.3kPa로 낮게 조 사되었다. 양액의 pH는 계절에 따라 차이가 없었으나 EC는 봄과 여름에 적정 범위를 벗어난 것으로 나타났다. 외적 특성 과 절화수명은 스마트팜 내에서 많이 재배되고 있는 ‘Egg Tart’, ‘Flash Dance’, ‘Pink Yoyo’, ‘Super Sensation’ 품종을 조 사하였다. 외적 특성 분석 결과, 대부분의 품종이 다른 계절에 비해 겨울에 절화장이 길었으나 줄기가 얇았고 소화수가 적었 다. 여름에는 꽃의 크기가 작았으며 화색이 퇴색되어 명도인 L값이 다소 높고, a값과 b값이 낮아 다른 계절보다 선명하지 않은 것으로 조사되었다. 절화수명 조사 결과, ‘Egg Tart’ 품종 은 계절별 차이가 없었으나 ‘Flash Dance’, ‘Pink Yoyo’, ‘Super Sensation’ 품종은 가을에 가장 길었으며 세 품종 모두 겨울, 여름 순으로 절화수명이 다소 짧은 것으로 조사되었다. 이는 여름의 고온과 겨울의 일적산광량 부족 및 과습한 환경이 꽃 의 크기와 화색발현, 절화수명 감소에 부정적인 영향을 미치 는 것으로 판단된다. 따라서, 고품질의 절화 장미가 생산 될 수 있도록 이에 적합한 스마트팜 환경 제어 시스템 개발과 현 장 적용을 통한 개선이 필요하며, 현재, 본 연구의 스마트팜에 서는 지상부 복합 환경 제어가 가능하기 때문에 축적한 자료 들을 이용한 빅데이터 분석 및 의사 결정 지원시스템이 갖춰 진다면, 2세대 스마트팜으로 발전 가능성이 높을 것으로 판단 된다.

The aim of the present study was to investigate the differences in volatile profiles among different Korean chrysanthemum cultivars grown as cut flowers. To optimize a method for sampling and comparing scents, the scents were evaluated by electronic nose (E-nose) at different flowering stages and in different organs and cultivars. The values of maximum resistance changes of metal oxide semiconductor sensors and relative aroma intensity were highest at flowering stage III (full flower stage of ray florets and initial opening disc florets) among different stages and in disc florets among different floral organs of cut chrysanthemums. Among the 12 chrysanthemum cultivars, the highest values for response change and relative aroma intensity were observed in the flowers of the ‘Ilweol’ cultivar. To compare scent patterns among the cultivars, E-nose sensor data was subjected to multivariate statistical analysis. Principal component analysis and discriminant function analysis of the volatile metabolic profile data indicated that chrysanthemum samples were clearly discriminated in a cultivar-dependent manner. These results show that different cultivars are characterized by distinct volatile profiles. Hierarchical cluster analysis showed that the 12 chrysanthemum cultivars were separated into 3 main groups according to the relationship of volatile profiles; however, chrysanthemum cultivars were not clustered according to the flower shape. We propose that these results could be used as the basis on which to improve the breeding of cut chrysanthemums based on volatile characteristics.

화훼류 중 절화류의 화색과 향기 특성을 조절하는 것은 주 요한 육종 목표로써 인지되어 왔다. 최근 다양한 소비자 계층이 증가하면서 파란색 장미, 카네이션 등과 같은 특이화색이 라든지, 독특한 향기를 갖고 있거나 그 강도를 조절하고자 하 는 연구방향 또한 다양해졌다. 그러나 이것은 일반적으로 수 행하고 있는 교배방식으로는 특정 목표형질을 가진 품종을 개 발하기란 쉽지가 않다. 그래서 화색과 향기와 관련한 형질을 조절할 수 있는 유전공학적인 방법뿐만 아니라 다방면의 연구 가 진행되어 왔다. 이는 화색과 향기의 관련 식물 대사산물을 생산 하는 것을 비롯하여 유전공학적인 방법으로 조절하는 방 식 등 여러 가지 방법이 있다. 많은 예 중에 화훼작물의 화색 과 향기를 조절한 성공한 사례를 바탕으로 어떻게 하면 우리 가 원하는 방향에 가까운 화색과 향기의 특정 형질을 만들어 낼 수 있을지에 대해 정리해보고자 하였고, 이러한 것들은 잘 응용하여 추후 좀 더 많은 화색과 향기를 만들어낼 수 있는 전략을 수립하는 데 도움이 되고자 한다.

This study investigated the regenerative and healing effect of spirulina on corneal epithelial injury by acid burn in zebrafish. Corneal epithelium of adult zebrafish was evaluated at 0, 12, 24, 48 h after acid burn injury with or without immersion with 0.02 and 0.04 mg/mL of spirulina water extract. The pathological changes of corneal epithelium were assessed by light microscopy. Gene and protein expressions of proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP) 9 and MMP13 were determined by immunohistochemistry or real-time PCR. Corneal epithelium was denuded totally after acid burn and gradually regenerated. PCNA-positive cells significantly increased in spirulina treated group. MMP9 and MMP13 mRNA transcripts were significantly decreased in spirulina treated groups. In conclusion, spirulina has regenerative and healing properties by increased keratocyte proliferation, and inhibited extracellular matrix degradation during the regeneration process of corneal epithelial injury by acid burn in zebrafish.

The treatment of microbial infections requires a large use of antibiotics which is, partially, responsible for the appearance of resistant strains to antibiotics in dairy cows. However, many photochemical compounds, including the essential oils, are becoming interesting as potential source of natural bioactive molecules. The antibacterial activity of the studied essential oils was evaluated by aromatogram and microdilution in medium liquid. The results show that the essential oil of Thymus fontanesii has the biggest antibacterial action against all the bacterial strains comparing with the Eucalyptus oil. However, the aqueous extracts of Thymus fontanesii and Eucalyptus indicate a moderate antibacterial activity against the strains of Staphylococcus aureus. On the other hand there is no effect on Escherichia coli strains. The most strong activity inhibitory was get with the essential oil of Eucalyptus against Staphylococcus aureus strains with CMI of 0.39 μl/ml for Staphylococcus aureus ATCC and 1.562 μl/ml for Staphylococcus aureus pathogen in comparison with the essential oil of Thymus fontanesii which is more active against the Escherichia coli strains. The aqueous extract of Eucalyptus showed the best CMI and CMB against the Staphylococcus aureus strains in comparison with the aqueous extract of Thymus fontanesii. Comparative tests to the activity have been made with cefoxitin and gentamicin discs.

There have been debates on adoption of corporate laws regarding electing independent audit committee members separately and double derivative suit, as well as mandatory cumulative voting to improve corporate governance in Korea. This article examines whether mandatory or market based approaches are desirable to improve corporate governance in Korea. It will explore the ways to strengthen the independence of the board of directors and audit committees. Firstly, this article studies the independence of outside directors in the U.S. and Korea. The independence of the board of directors has been weak in Korea due to controlling shareholders and circular share-holding ownership structure among big business groups, even though there have been attempts to improve this situation. Secondly, this article examines the current role of outside directors, audit committees, and cumulative voting in the U.S and in Korea to find out positive changes in corporate governance Korea. Lastly, his article will discuss the appropriate direction between mandatory and market based soft law approaches on corporate governance in Korea. It will argue that Korea needs to strengthen the monitoring function of the board of directors, independence of outside directors and audit committee.