어류병원성 세균 및 C2C12 근원세포에 대한 polyamine 계열 물질인 spermidine의 항균 및 항산화 활성

황보현,최은옥,김민영,지선영,홍수현,박철,차희재,김석만,김희수,황혜진,최영현 (사)한국해양바이오학회 2019 한국해양바이오학회지 Vol.11 No.2

We compared the antibacterial activities of spermidine and astaxanthin against two gram-positive bacteria such as Streptococcus parauberis and S. iniae to find new antibacterial candidates. We also evaluated the preventive effects of spermidine against oxidative stress-induced cytotoxicity in C2C12 myoblasts. Our results indicated that spermidine has more significant antibacterial activities than astaxanthin against both two fish pathogenic bacteria as well as gram-negative bacteria Escherichia coli used as a control group. Minimum inhibitory concentration and minimum bactericidal concentration of spermidine were 0.25 mM and 1 mM against S. parauberis, 1 mM and 3 mM against S. iniae, and 0.5 mM and 1.5 mM against E. coli, respectively. In addition, the postantibiotic effect lasted from 7 h, 5 h and 6 h for S. parauberis, S. iniae and E. coli, respectively. The results also showed that the decreased C2C12 cell viability by H2O2 could be attributed to the induction of DNA damage and apoptosis accompanied by the increased production of reactive oxygen species, which was remarkably protected by spermidine. Additionally, the antioxidant effect of spermidine was associated with the activation of Nrf2 signaling pathway. According to the data, spermidine may be a potential lead compound which can be further optimized to discover novel antibacterial and antioxidant agents.

Rheotaxis based high-throughput motile sperm sorting device

황보현,이동규,황승준,백중환,김병규 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.6

A progressive motile sperm sorting device with a diffuser-type microfluidic channel is proposed to improve fertilization in assisted reproductive technologies. When sperm cells swim against a fluid flow, they are positioned according to their motility in specific channel zones. A numerical simulation is carried out in a meso-sized diffuser-type channel which can realize high throughput to verify the working principle and the sorting device is fabricated based on the simulation result. Furthermore, to analyze the condition of the semen and investigate the experimental results, a novel image processing method is proposed. With the proposed analyzing technique, the sperm sorting experiment is performed in the channel using the canine semen sample. As a result, the %motility increases from 59.89 to 69.36%, however, it does not satisfy the reported guideline for canine sperm motility (%motility > 70%). Therefore, we perform a washing process by injecting DPBS fluids to improve indexes related to motility. After double washing procedures, we could increase %motility from 59.89 to 82.24%, motile sperm rate from 33.38 to 53.10% and motility index from 26.35 to 49.44 in Zone A, comparing to the prepared sample.

유역모형을 이용한 낙동강 유역에서의 비점오염원 정량화

황보현,김동일,윤영삼,한건연 한국수자원학회 2010 한국수자원학회논문집 Vol.43 No.4

최근 들어 도시화와 이상기후의 영향으로 유역에서의 유출특성과 오염물질 발생특성도 변화하고 있고 이에 따라 정교한 유역 수질분석이 요구되고 있다. 유역의 비점오염원 관리를 위하여 충분조건을 갖추어야 할 정량분석이 선행되어야 하나 점오염원 관리와 달리 자연 내의 복잡한 현상을 반영하여야 하기 때문에 비점오염원의 정량화 해석에 어려움을 겪어왔다. 강우 및 유출량 관계와 덧붙여 오염물질이 하천수질에 영향을 미치기까지 도달시간 해석 및 점오염원과 비점 오염원의 Recent urbanization and abnormal weather have induced enormous changes in the characteristics of both runoff and pollutant occurrence. Thus, sophisticated watershed modeling of water quality is required. In order to manage non point sources in a watershed

Numerical simulation and experimental validation for a novel dielectrophoresis activated cell sorter to achieve high throughput and efficiency

황보현,이동규,김병규,이재욱 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

Although previously developed Dielectrophoresis activated cell sorters (DACSes) have achieved high separation efficiency, limitations still exist with respect to the low throughput. In this paper, therefore, a numerical analysis is presented for a novel DACS to achieve not only high efficiency but also high throughput. Additionally, experimental validation is performed based on the results of a numerical simulation. First, streamlines in the channel are investigated according to various flow rate ratios in each outlet. After cells are deflected by a sufficient amount of dielectrophoretic force, they arrive at the tip of the last electrode pair. Their movement is then determined by hydrodynamic force. Therefore, it is important to confirm whether or not the streamline at the tip of the last electrode pair connects to the target area. Based on the streamline analysis results, the particle trajectory under various AC electric fields is investigated using a threedimensional analysis. Accordingly, an input voltage condition (7 Vp-p at 10 kHz) is selected to confirm the influence of dielectrophoretic force. Conclusively, optimal flow rates under the determined input voltage condition are selected as 10 μl/min and 20 μl/min in outlet A (target area) and outlet B (non-target area), respectively. In order to validate the feasibility of the selected flow rates, a separation test is performed employing a K562 cell – bone marrow cancer cell – as a target cell. In the experiment, the proposed DACS achieves a high throughput of 45000 cells/min as well as a separation efficiency of 96.5% and recovery rate of 47.25%.

자리

황보현 고요아침 2010 열린시학 Vol.15 No.4

An analysis of first person pronouns and epistemic modality in academic writing

황보현,최호성 팬코리아영어교육학회 2014 영어교육연구 Vol.26 No.2

Theses written by Korean master’s students (MTs), dissertations written by Korean doctoral students (DDs), research articles written by Korean experts (KRs), and research articles written by native English-speaking experts (ERs) are analyzed to identify the ways in which the use of first person pronouns and epistemic modality reflect the author’s stance and level of certainty, respectively. The first person pronoun ‘I’ is most frequently used in ERs as a means of securing ownership, whereas KRs use this item the least. MTs, used this item the second most frequently. When it comes to the use of epistemic modality for the writer’s certainty, MTs and DDs use ‘will’ with the highest frequency, but in rather inappropriate ways and contexts. KRs show a preference for the use of certain items in the low probability group such as ‘may,’ ‘might,’ and ‘could,’ while ERs use many epistemic items from the same group as KRs but with more variation in grammatical classes.

순물류와 역물류 관리에 적합한 RFID 기반의 G-Pedigree 시스템과 G-code 체계 개발

황보현,윤종호,최명렬 한국정보통신설비학회 2010 정보통신설비학회논문지 Vol.9 No.3

차적의 비균일 채널 간격 분할 방식 ( Suboptimum Unequal Channel Spacing Technique )

황보현 한국통신학회 1996 한국통신학회 워크샵 Vol.- No.-

Corni Fructus attenuates testosterone-induced benign prostatic hyperplasia by suppressing 5α-reductase and androgen receptor expression in rats

황보현,권다혜,최은옥,김민영,안규임,지선영,김종식,김경일,박노진,김범회,김기영,홍수현,박철,정지숙,최영현 한국영양학회 2018 Nutrition Research and Practice Vol.12 No.5

BACKGROUND/OBJECTIVES: Benign prostatic hypertrophy (BPH) is a major cause of abnormal overgrowth of the prostate mainly in the elderly. Corni Fructus has been reported to be effective in the prevention and treatment of various diseases because of its strong antioxidant effect, but its efficacy against BPH is not yet known. This study was designed to evaluate the therapeutic efficacy of Corni Fructus water extract (CF) in testosterone-induced BPH rats. MATERIALS/METHODS: To induce BPH, rats were intraperitoneal injected with testosterone propionate (TP). Rats in the treatment group were orally administered with CF with TP injection, and finasteride, which is a selective inhibitor of 5α-reductase type 2, was used as a positive control. RESULTS: Our results showed that the increased prostate weight and histopathological changes in BPH model rats were suppressed by CF treatment. CF, similar to the finasteride-treated group, decreased the levels of testosterone and dihydrotestosterone by TP treatment in the serum, and it also reduced 5α-reductase expression and concentration in prostate tissue and serum, respectively. In addition, CF significantly blocked the expression of the androgen receptor (AR), AR co-activators, and proliferating cell nuclear antigen in BPH rats, and this blocking was associated with a decrease in prostate-specific antigen levels in serum and prostate tissue. CONCLUSIONS: These results suggest that CF may weaken the BPH status through the inactivation of at least 5α-reductase and AR activity and may be useful for the clinical treatment of BPH.

다중모드/다중대역 무선통신 수신기를 위한 재구성 가능 CMOS 저잡음 증폭기

황보현,유창식,정재훈,김신녕,정찬영,이미영 대한전자공학회 2006 電子工學會論文誌-SD (Semiconductor and devices) Vol.43 No.10

Reconfigurable CMOS low-noise amplifier (LNA) has been developed for multi-mode/multi-band wireless receiver. By employing common-gate input stage, the performance can be optimized for multiple operation bands by simply controlling the output load impedance. Although the conventional common-gate LNA has larger than 3dB noise figure (NF), the newly developed negative feedback scheme enables the common-gate input LNA to have less than 2dB NF. To have optimum linearity performance of wireless receiver, the gain of the LNA can be controlled. The LNA implemented in a 0.13mm CMOS technology shows 19~20dB voltage gain, 1.7~2.0dB NF, -2dBm iIP3 at 1.8~2.5GHz frequency range. The LNA dissipates 7mW from a 1.2V supply voltage. 다중모드/다중대역 무선 통신 수신기에 사용할 수 있는 재구성 가능한 CMOS 저잡음 증폭기를 개발하였다. 입력단에 common-gate 트랜지스터 회로를 사용함으로써 출력단의 impedance 만을 조절하면 여러 주파수 대역에서 최적의 특성을 갖도록 하였다. 통상적인 common-gate 형태의 저잡음 증폭기는 3dB 이상의 높은 잡음 지수를 갖는데, 부귀환 회로를 사용하여 2dB 이하의 잡음 지수를 갖도록 하였다. 무선 수신기의 선형성 특성을 최적화할 수 있도록 저잡음 증폭기의 전압 이득을 조절할 수 있도록 하였다. 0.13mm CMOS 공정을 이용하여 개발하였으며 1.8~2.5GHz 대역에서 전압 이득은 19~20dB, 잡음 지수는 1.7~2.0dB, third-order input intercept point (IIP3)는 -2dBm이다. 1.2V의 공급 전압에서 7mW의 전력을 소모한다.