17β-estradiol에 노출된 저서성 요각류 Tigriopus japonicus s.l.의 세대간 생활사 및 형태학적 변이 연구

방현우,임동현,이원철 한국해양과학기술원 2010 Ocean and Polar Research Vol.32 No.4

To characterize ecotoxicological responses to a natural estrogen, 17β-estradiol, we evaluated the life-history of the parental (F0) and first generation (F1) of the harpacticoid copepod, Tigriopus japonicus sensu lato. We evaluated the survival of nauplii and copepodites, the number of days until the emergence of copepodites and adult males, the sex ratio, brooding success, and the first brooding day of adult females. No significant differences in the survival rate were noted in response to treatments with different concentrations of 17β-estradiol. However, 17β-estradiol induced developmental delay and skewed the sex ratio toward males. Copepod development was delayed significantly in the 0.1 and 1 μg l−1 17β-estradiol treatment groups relative to the control group, with a more pronounced delay in the F1 group. Body length and biomass were significantly smaller in the 17β-estradiol treated groups than in the controls. The male emergence of T. japonicus s.l. was very high in the 10 and 30 μg l−1 17β-estradiol treatment group. Furthermore, exposure to 17β-estradiol resulted in morphological deformities such as shrinking and swelling of the urosome, twisted setae of the caudal rami, setal loss of swimming legs, abnormal segmentation of antennules, and dwarfism.

A new species of the genus Ameiropsis Sars G.O., 1907 (Copepoda; Harpactiocoida) from Korea

방현우 국립생물자원관 2023 Journal of species research Vol.12 No.3

The family Ameiridae Boeck, 1865 (Copepoda; Harpacticoida) consists of about 380 species in 47 genera, but only 10 species have been reported in Korea. A benthic ameirid species was collected from the East Sea of Korea. Specimens were identified as members of the genus Ameiropsis Sars G.O., 1907, and this is the first record of the genus Ameiropsis in the Pacific Ocean. Ameiropsis gyeongjuensis sp. nov. is morphologically similar to A. mixta Sars G.O., 1907 and A. longicornis Sars G.O., 1907 from Norway. However, the new species is clearly distinguishable from the others based on the following morphological characteristics: the proximal segment of antennary exopod with a bulge in the middle, and with one pinnate seta; the distal segment of antennary exopod with a thickened, blade-shaped outer seta; and female P5 baseoendopod with five setae and exopod with six setae. An identification key to species is provided for the 11 valid species of the genus Ameiropsis.

Optimal microchannel design using genetic algorithms

방현우,이원구,박준하,윤호영,민정기,한동철 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.5

This paper presents a novel method of optimizing particle-suspended microfluidic channels using genetic algorithms (GAs). The GAs can be used to generate an optimal microchannel design by varying its geometrical parameters. A heuristic simulation can be useful for simulating the emergent behaviors of particles resulting from their interaction with a virtual microchannel environment. At the same time, fitness evaluation enables us to direct evolutions towards an optimized microchannel design. Specifically, this technique can be used to demonstrate its feasibility by optimizing one commercialized product for clinical applications such as the microchannel-type imaging flow cytometry of human erythrocytes. The resulting channel design can also be fabricated and then compared to its counterpart. This result implies that this approach can be potentially beneficial for developing a complex microchannel design in a controlled manner.

使用者의 懲戒權 行使에 關한 硏究 - 刑事法的 原則의 適用 可能性을 中心으로 -

방현우 노동법이론실무학회 2008 정기학술대회 Vol.2008 No.-

4-nonylphenol에 노출된 저서성 요각류 Tigriopus japonicus s.L.의 생활사, 형태와 유전자 발현

방현우,이원철,이승한,곽인실 한국하천호수학회 2008 생태와 환경 Vol.41 No.1

Perpendicular magnetic anisotropy properties of tetragonal Mn3Ga films under various deposition conditions

방현우,Woosuk Yoo,최영하,유천열,홍정일,Janez Dolin sek,정명화 한국물리학회 2016 Current Applied Physics Vol.16 No.1

The tetragonal Mn3Ga films exhibited high perpendicular magnetic anisotropy, low saturation magnetization, and high spin polarization, which satisfy the criteria of spin-transfer-torque based devices. For practical device applications, it is necessary to improve the interface nature and optimize the deposition conditions. We fabricated thin films of tetragonal Mn3Ga directly on MgO(100) without any buffer layer by using DC/RF magnetron sputtering method. We investigated the crystallinity, microstructure, and magnetic properties with varying the deposition conditions; such as deposition temperature (350 e450 C), RF power (25e40 W), and Ar gas pressure (2e7 mTorr). X-ray diffraction data revealed that the growth direction is perpendicular to the film plane, i.e., the c axis. Scanning electron microscope images showed that the top surface is flat with a maximum thickness of 290 nm. The optimal deposition conditions are 400 C, 35 W, and 5 mTorr in our sputtering system. For the field perpendicular to the film plane, clear hysteresis loop was observed with the saturation magnetization MS ¼ 100 emu/cc at room temperature. By extrapolating the hard magnetization data for the field parallel to the film plane, the anisotropic energy was estimated about K1 ¼ 1 106 J/m3.

Cross-generational Effect of Bisphenol A on the Harpacticoid Copepod Tigriopus west: A Full Life Cycle Toxicity Test

방현우 한국환경생물학회 2018 환경생물 : 환경생물학회지 Vol.36 No.4

The purpose of this study was to assess cross-generational effects of bisphenol A exposure in benthic copepods, Tigriopus west. Nauplii (<24 hours old) were exposed to graded concentrations of bisphenol A, and toxicity end-points such as survival, development, sex ratio, and fecundity were measured. F1 generations were grown under innoxious conditions, and similarly assessed. Significant differences were observed in development of nauplii and copepodites, between exposed and non-exposed copepods; however, there were no differences in survival of nauplii or copepodites, sex ratio, or brooding rate in parental generation. In contrast, in the F1 generation, there were significant differences between the control group and exposed group in survival and development of nauplii. Length, width, and biomass of parental and F1 generations were reduced in the exposed group compared to the control group. In addition, some deformities, such as swelling of the prosome, abnormally shaped egg sac, and dwarfism were observed after exposure to bisphenol A. So, our study demonstrates that a cross-generation toxicity test and monitoring of morphological deformities in harpacticoid copepods, can be useful for development of potential bioindicators for environmental monitoring, and assessment of chemical impact.

남극 King George Islands, Marian Cove의 중형저서생물 군집 구조에 관한 연구

방현우 ( Hyun Woo Bang ),강성호 ( Sung Ho Kang ),이원철 ( Won Choel Lee ) 한국환경생물학회 2005 환경생물 : 환경생물학회지 Vol.23 No.2

남극 King George Island, Marian Cove에 서식하는 중형저서생물 군집구조, 수직분포 그리고 요각류 군집을 조사하기 위해 2002년 12월 Marian Cove내 5개 정점과 Nelson Island 북동쪽연안 1개 정점에서 자유 낙하 중력 시추기를 이용하여 채집을 실시하였다. 조사기간 중 중형저서생물은 11개 분류군이 발견되었으며, 출현한 중형저서생물의 총 개체수는 322~1575 indiv. l0cm^(-2) 범위로 평균 781 indiv. 10cm^(-2)로 나타났다. 선충류의 평균 개체수는 693 indiv. 10cm^(-2)로 전체 중형저서생물의 88.7%를 차지하는 우점 분류군으로 나타났으며, 저서성 요각류가 53 indiv. 10cm^(-2)로 6.8%를 차지하며 그 뒤를 이어 우점 하는 분류군으로 나타났다. 퇴적물 깊이에 따른 중형저서생물의 수직분포를 보면 70% 이상의 개체가 표층 0~2cm에 집중되어 나타났으며, 깊이 5cm 이하에서는 5% 이하의 낮은 분포를 보였다. 각 정점별 평균 총 생물량은 41~360 μgC 10cm^(-2) 범위로 평균 205 μgC 10cm^(-2)로 나타났으며, 가장 높은 비율을 차지하는 분류군 역시 선충류로 전체 생물량의 62.4%를 차지했다. SPSS를 이용한 상관계수 분석 결과 온도가 중형저서생물 군집에 영향을 미치는 것으로 나타났으며, 염분도와 유기물 총량은 중형저서생물 군집에 별다른 영향을 끼치지 못하는 것으로 나타났다. CCA를 이용한 퇴적물 입자와 각 분류군과의 상관관계 분석 결과 다모류, 빈모류 그리고 쿠마류는 실트 및 점토와 높은 상관관계를 가지며, 요각류와 부등각류, 이매패류는 모래, 유공충류는 잔자갈 그리고 동문동물류와 패충류는 중자갈과 높은 상관관계를 갖는 것으로 조사되었고, 선충류의 경우 각 입자와 상관관계가 매우 낮게 나타났다. 환경오염을 모니터링 하는데 가장 유용한 분류군인 요각류는 모두 9개과 19개 속 19개 종이 출현했으며, 가장 다양한 분류군이 나타난 정점 B에서 7개과 13개 속 13개 종이 출현하였다. The community structure, vertical distribution and harpacticoids composition of the meiofauna community were observed from five stations in Marian Cove, King George Island and one station on the northeastern side of Nelson Island. Sample was taken by a free-fall corer in December 2002. Generally, 11 taxa of meiofauna were found, and meiofauna abundance ranged from 322 to 1575 indiv. 10 cm^(-2) (mean 781 indiv. 10 cm^(-2)). Nematodes were the most dominant group, making up 89% of total meiofauna, followed by harpacticoids (6.8%). Benthic harpacticoids appeared 19 species of nine families at all the stations, and most various taxa appeared at station B (13 species of seven families). For vertical distribution, more than 70% of meiofauna was concentrated in the upper 0~2 cm sediment layers, and the density abruptly decreased with depth in all the stations. Total biomass of meiofauna varied between 41 and 360 μgC 10 cm-2, and overall mean biomass was 205 μgC 10 cm^(-2). Also nematodes had the highest percentage of total maiofauna biomass (62.4%). The analysis results of Canonical Correspondence Analysis between meiofauna community and sediment grain size showed that polychaets, oligochaets and cumaceans were influenced by silt&cray, and sand, granule and pebble had a influence on harpacticoids, kinorhynchs and ostracods respectively. But nematodes were not affected by sediment grain size.

使用者의 懲戒權 行使에 關한 硏究 - 刑事法的 原則의 適用 可能性을 中心으로 -

방현우(Bang, Hyun-Woo) 노동법이론실무학회 2008 노동법포럼 Vol.- No.1

In modern industry, companies seek to effectively utilize their human capital by operating an employer-friendly organizational model that promotes the flexible and intense management of labor resources. The foundation of this system is the process by which employers and employees mutually agree to enter into employment contracts with each other. Under this arrangement, employees agree to perform the labor duties stipulated by the contract as and when requested by the employer. Moreover, the contract also requires the employee to observe additional corporate obligations. These include observance of the corporate code of conduct, protection of confidential information, maintenance of the good image of the company and so on. To the extent that employees provide labor services in a diligent manner and fulfill the duties requested by the employer, the company has no need to apply procedures governing contract violations or take related disciplinary action against the employee. However, when the employer believes that an employee has committed an act of misconduct or has otherwise refused to execute the employers requests, the employer may attempt to take disciplinary action against the employee. In such cases, it is likely that the employer's decision to initiate disciplinary procedures will have significant consequences for the employee. Firstly, the employer will endure substantial censure, including in the worst case the possibility of dismissal. Secondly, unilateral disciplinary action on the part of the employer may cause substantial financial distress for the employee. In the modern employer-employee relationship, the right  of the employer to take disciplinary action against employees who violate internal codes and procedures or refuse to obey instructions, and the role that these procedures play in restraining the actions of other employees, is known as a distinct sanction. Ultimately, the overall relationship between the employer and the employee is governed by the labor contract signed by the two parties. This contract should incorporate the coordinated interests of both parties and be the product of negotiated mutual agreement on an equal partner basis. Given this contractual background, it is necessary to describe the theoretical basis behind the employer's right to take disciplinary actions against an employee, to clarify the boundaries of such actions and to identify more effective supervisory tools that can be aligned with disciplinary objectives. In the first place, it is necessary to note that Korean labor law does not contain any specific provisions relating to an employer's right to take disciplinary action. Rule 1 of Article 30 of the Labor Code, which provides protection against dismissal and other actions injurious to the employee, simply states that employers can not take disciplinary action against employees without 'appropriate reason. While Rule 1 of Article 30 contains the general statement that there is no definition or boundary specifying the limit of what might constitute 'appropriate reasons', in practice this statement is interpreted based on the content of company employment laws or collective agreements. However, where the provisions of such company employment laws or collective agreements are held to be unreasonable, the legal interpretation of whether or not an employer has unjustly taken disciplinary action against an employee becomes a matter of case-by-case legal judgment. For this reason, employers seeking to take disciplinary action against an employee must take care to ensure that they provide an appropriate reason for the disciplinary action taken, conduct the disciplinary process with procedural fairness and make sure that the disciplinary action taken is not disproportionate to the original violation committed by the  employee. Failure to adequately take these steps may be seen as tantamount to an abuse of the employer's right to take disciplinary action, especially in cases where the

4-tert-octylphenol에 노출된 저서성 요각류 Tigriopus japonicus s.l.의 발생지연 현상

방현우(Hyun Woo Bang),이원철(Wonchoel Lee),곽인실(Inn-Sil Kwak) 환경독성보건학회 2008 환경독성보건학회지 Vol.23 No.2

The ecotoxicological effects of 4-tert-octylphenol were observed on Harpacticoid copepoda Tigriopus japonicus s.l. gathered and cultured from tidal pool of Korean coast. There were no significant differences in survival rate (except 10 ㎍/ℓ; 70.00%) and sex ratio (except 30 ㎍/ℓ) on T. japonicus s.l. exposed to 4-lert-octylphenol. However, 4-rert-octylphenol induced developmental delay (copepodite emergence day and adult male mergence day) and retardation of first brooding day of adult female. Moreover the body size and biomass decreased at 4-tert-octylphenol exposure. As a result, detailed life-cycle research of T. japonicus s.l. may yield potential bioindicators for environmental monitoring and assessment.