• Title/Summary/Keyword: Han-Ki Choi

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Effect of Sublethal Doses of Imidacloprid on the Green Peach Aphid, Myzus persicae (Imidacloprid의 아치사량이 복숭아혹진딧물의 생물적 특성에 미치는 영향)

  • Choi, Byeong-Ryeol;Lee, Si-Woo;Song, Yoo-Han;Yoo, Jai-Ki;Chung, Bu-Keun
    • The Korean Journal of Pesticide Science
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    • v.9 no.4
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    • pp.374-379
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    • 2005
  • Sublethal dose effect of imidacloprid on green peach aphid (Myzus persicae) was investigated. Nymphs of green peach aphid newly produced were counted on 4 days after sub-lethal dose treatment of imidacloprid. Numbers of nymph were not significantly different between $LC_1$ treatment and untreated control. Their numbers of nymph were 8.8 and 12.7 at $LC_1$ and untreated control, respectively. When they were tented at $LC_{10}$, $LC_{30}$ and $LC_{50}$. their numbers of newly produced nymph were 6.0, 5.1 and 3.9 and reduction rates were 52.7%, 59.8% and 69.3% at each treatment compare to untreated control. Reduction rates of newly laid nymph were proportional to the concentrations of imidacloprid treated. Repellent effect of aphid to imidacloprid was bigger in dipping than in watering method. Secretion amount had negative correlation with imidacloprid concentration in dipping method and suppression of secretion went up to 96%. In watering method, amount of secretion did not show any difference between insecticide concentration, but suppression, compared to untreated control, was over 97%.

Study of Selective Etching of GaAs-based Semiconductors using High Density Planar Inductively Coupled $BCl_3/CF_4$ Plasmas (고밀도 평판형 유도결합 $BCl_3/CF_4$ 플라즈마에 의한 GaAs 계열반도체의 선택적 식각에 관한 연구)

  • Choi, Chung-Ki;Park, Min-Young;Jang, Soo-Ouk;Yoo, Seung-Ryul;Lee, Je-Won;Song, Han-Jung;Jeon, Min-Hyon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.46-47
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    • 2005
  • 이번 연구는 $BCl_3/CF_4$ 플라즈마를 사용하여 반도체소자 제조 시 널리 이용되는 GaAs 계열반도체 중 대표적인 재료인 GaAs/AlGaAs 및 GaAs/InGaP 구조를 선택적으로 건식 식각한 후 분석한 것이다. 공정변수로는 ICP 소스파워를 0-500W, RIE 파워를 0-50W 그리고 $BCl_3/CF_4$ 가스 혼합비를 중점적으로 변화시켰다. $BCl_3$ 플라즈마만을 사용한 경우 (20$BCl_3$, 20W RIE power, 300W ICP source power, 7.5mTorr) 는 GaAs:AlGaAs의 선택비가 0.5:1 이었으며 이때 GaAs의 식각률은 ~2200${\AA}/min$ 이었으며 AlGaAs의 식각률은 ~4500${\AA}/min$ 이었다. 식각 후 표면의 RMS roughness은 < 2nm로 깨끗한 결과를 보여주었다. 15% $CF_4$ 가스가 혼합된 $17BCl_3/3CF_4$, 20W RIE power, 300W ICP source power, 7.5mTorr의 조건에서 3분 동안 공정한 결과 순수한 $BCl_3$ 플라즈마만을 사용한 경우보다 표면은 다소 거칠었지만 (RMS roughness: ~8.4) GaAs의 식각률 (~980nm/min)과 AlGaAs와 InGaP에 대한 GaAs의 선택도 (GaAs:AlGaAs=16:1, GaAs:InGaP=38:1)는 크게 증가하였다. 그리고 AlGaAs 및 InGaP의 경우 식각 시 나타난 휘발성이 낮은 식각 부산물 ($AlF_3:1300^{\circ}C$, $InF_3:1200^{\circ}C$)로 인하여 50nm/min 이하의 낮은 식각률을 보였고, 62.5%의 $CF_4$가 혼합된 $7.5BCl_3/12.5CF_4$플라즈마의 조건에서는 AlGaAs 및 InGaP에 대한 GaAs의 선택도가 각각 280:1, 250:1을 나타내었다.

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Correction of Retracted Ala Using Spacer Graft in Secondary Cleft Lip and Nose Deformity (이차 구순비 변형 환자에서 Spacer Graft를 이용한 콧방울뒤당김(retracted ala)의 교정)

  • Han, Kyu-Seok;Choi, Hyun-Gon;Shin, Dong-Hyeok;Kim, Soon-Heum;Hwang, Eun-A;Uhm, Ki-Il
    • Archives of Plastic Surgery
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    • v.38 no.4
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    • pp.376-382
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    • 2011
  • Purpose: In patients with unilateral cleft lip and nose deformity, alar retraction is commonly seen on the non-cleft side after cleft side is corrected. Spacer graft was used to drag down the inferior border of the alar cartilage of the non-cleft side so as to match the cleft side. By performing spacer graft and septal extension graft together, symmetry and cosmetic improvements were achieved. Methods: Seven unilateral cleft lip and nose deformity patients underwent surgery for alar retraction correction. The median age was 24 years (ranged from 15 to 34 years), and the median follow-up period was 7.4 months (ranged from 6 to 12 months). The perpendicular length from the longitudinal axis of the nostril to the alar rim, the nasolabial angle and the ala-labial angle were measured in the lateral view photo. The longest perpendicular length from the cephalic border of the alar rim to the parallel line of the alar base was measured in the frontal view photo. Results: Improvement in alar retraction was seen after the surgery. There were no specific complications during the follow-up and the symmetry of both nostrils was satisfactory. No increase in the nasolabial angle or exposure of the nostrils was seen after the tip projection via tip plasty. Conclusion: The fundamental factor in correcting alar retraction with secondary cleft lip and nose deformity is repositioning the alar rim with spacer graft, which seems to be more physiologic than other methods. The method combining spacer graft with septal extension graft will bring symmetry as well as more cosmetic improvement in correction of alar retraction with secondary cleft lip and nose deformity.

Antinociceptive Efficacy of Korean Bee Venom in the Abdominal Pain of the Mouse (마우스 복통에 대한 한국산 봉독의 진통 효과)

  • Kim, Joong-Hyun;Lee, Hye-Yun;Kim, Myoung-Hwan;Han, Tae-Sung;Cho, Ki-Rae;Kim, Gon-Hyung;Choi, Seok-Hwa
    • Journal of Veterinary Clinics
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    • v.24 no.3
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    • pp.320-324
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    • 2007
  • This study was undertaken to assess the antinociceptive effect of Korean bee venom (BV) in mice. Korean BV was collected using BV collector devices in which an electrical impulse is used to stimulate the worker bee (Apis mellifera L.) to sting and release venom. After collection, whole BV was evaporated until dry using the BV collector. Experiments were performed on male ICR mice (weighing $30{\sim}35g$, 6 weeks old). Mice were divided into 4 groups, each comprising 8 mice. BV was diluted and amounts of 6 mg/kg body weight (BW), 0.6 mg/kg BW and 0.06 mg/kg BW were tested. BV was subcutaneously injected to produce an antinociceptive effect and the antinociceptive efficacy was evaluated using a writhing test in mice. Intraperitoneal injection of acetic acid produced a tonic pain behavior, first observed at 3 to 9 min post-injection. This writhing response peaked at 20 min post-acetic acid injection, and then declined until it was undetectable at 60 min post-injection. The time elapse between the administration of acetic acid and the first observed pain behaviors indicated a dose-dependent suppressive effect. These results suggest that Korean BV may be used to achieve an antinociceptive effect for use in medical therapies.

Cardiovascular Safety Pharmacology of Sibutramine

  • Yun, Jaesuk;Chung, Eunyong;Choi, Ki Hwan;Cho, Dae Hyun;Song, Yun Jeong;Han, Kyoung Moon;Cha, Hey Jin;Shin, Ji Soon;Seong, Won-Keun;Kim, Young-Hoon;Kim, Hyung Soo
    • Biomolecules & Therapeutics
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    • v.23 no.4
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    • pp.386-389
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    • 2015
  • Sibutramine is an anorectic that has been banned since 2010 due to cardiovascular safety issues. However, counterfeit drugs or slimming products that include sibutramine are still available in the market. It has been reported that illegal sibutramine-contained pharmaceutical products induce cardiovascular crisis. However, the mechanism underlying sibutramine-induced cardiovascular adverse effect has not been fully evaluated yet. In this study, we performed cardiovascular safety pharmacology studies of sibutramine systemically using by hERG channel inhibition, action potential duration, and telemetry assays. Sibutramine inhibited hERG channel current of HEK293 cells with an $IC_{50}$ of $3.92{\mu}M$ in patch clamp assay and increased the heart rate and blood pressure ($76{\Delta}bpm$ in heart rate and $51{\Delta}mmHg$ in blood pressure) in beagle dogs at a dose of 30 mg/kg (per oral), while it shortened action potential duration (at $10{\mu}M$ and $30{\mu}M$, resulted in 15% and 29% decreases in $APD_{50}$, and 9% and 17% decreases in $APD_{90}$, respectively) in the Purkinje fibers of rabbits and had no effects on the QTc interval in beagle dogs. These results suggest that sibutramine has a considerable adverse effect on the cardiovascular system and may contribute to accurate drug safety regulation.

Fruit Quality of 'Wonhwang' Pear Trees with Low-pesticides and In Vitro Regrowth of Stem Cuttings as Affected by Time of Defoliation (시기별 적엽이 저농약 '원황'배의 과실품질과 삽수의 기내 재생장에 미치는 영향)

  • Kim, Byeong-Sam;Cho, Kyung-Chul;Ma, Kyung-Chul;Yun, Bong-Ki;Jung, Seok-Kyu;Han, Jeom-Hwa;Choi, Hyun-Sug
    • Korean Journal of Organic Agriculture
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    • v.23 no.3
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    • pp.469-480
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    • 2015
  • The study was conducted on the effects of time of defoliation on fruit quality of pear (Pyrus pyrifolia Nakai) trees, managing with low-pesticides, and regrowth of stem cuttings in vitro. Treatments included for 40% of uniform defoliation at early-August, end-August, and early-September, as well as control (no defoliation). Defoliation at early-September and control increased growth of water sprouts as well as concentrations of carbohydrates, total nitrogen, and free sugar in one-year old shoots. Defoliation at early-September and control increased fruit yield and mean fruit weight, with high soluble solids content and fruit surface color of $a^*$ observed for both defoliation at end-August and early-September. Defoliation at early-August increased rates of electrolyte leakage in stem cuttings at $-18^{\circ}C$ in vitro. There were no significantly different for germination rates of the cuttings between the treatments at -18 and $-21^{\circ}C$ in vitro, with the highest germination of the cuttings observed for defoliation at early-September and control at $-27^{\circ}C$. Therefore, orchard management should be performed to be minimized for defoliation of the spur leaves until end-August, causing from precipitation and pests.

Characteristics of Coals Extracted Using Solvent at Mild and High Temperature Conditions (온순조건과 고온조건에서 용매 추출한 석탄의 특성 비교)

  • Park, Keun Yong;Choi, Ho Kyung;Kim, Sang Do;Yoo, Ji Ho;Chun, Dong Hyuk;Rhim, Young Joon;Lim, Jeong Han;Lee, Si Hyun;Na, Byung Ki
    • Applied Chemistry for Engineering
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    • v.23 no.6
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    • pp.529-533
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    • 2012
  • In this study, we compare various physicochemical properties of solvent extracted coals obtained at both mild and high temperature conditions. In order to characterize the extraction behavior, experiments were performed using a sub-bituminous coal (Kideco) and a polar solvent (N-methyl-2-pyrrolidinone, NMP), where the extraction temperature and the effect of solvent recycling were evaluated. As the extraction temperature increased up to $350^{\circ}C$, an extraction yield and a calorific value of the extracted coal increased, while an ash content of the extracted coal decreased. FT-IR results revealed that the surface of the coal extracted at $350^{\circ}C$ was found to contain more amide, aromatic ester, and aliphatic ether groups than that at the lower temperatures. The result of MALDI-TOF/MS analysis confirmed that the smaller molecules with 300~500 m/z were extracted at a mild condition, while the bigger molecules in the range of 500~1500 m/z were extracted at the high temperature.

Risk Factor Analysis of Endoscopic Dilation Procedure for the Management of Subglottic Stenosis in Pediatric Patients (성문하 협착 소아 환자에 대한 내시경적 기도 확장 시술 후 치료 실패 위험 요인 분석)

  • Park, Min Hae;Choi, Nayeon;Song, Bok Hyun;Jeong, Han-Sin;Son, Young-Ik;Chung, Man Ki
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.31 no.1
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    • pp.19-26
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    • 2020
  • Background and Objective Endoscopic airway dilation is the primary treatment for pediatric subglottic stenosis (SGS) due to its feasibility and non-invasiveness. The aim of this study is to evaluate the risk factors for the failure of endoscopic airway dilation in pediatric patients with SGS. Materials and Methods This study reviewed medical records of 38 pediatric patients had endoscopic dilation from a single and tertiary referral center, retrospectively. The success of the endoscopic dilation procedure was defined as no dyspneic symptom without tracheostomy or laryngotracheal reconstruction. Demographic profiles, underlying disease, and Myer-Cotton SGS severity grade were recorded. Success rates and risk factors for the failure of treatment were analyzed. Results The SGS patients with severity grade I was most common. After mean 1.8 numbers of procedures, there were 23 patients (60.5%) in the success group and 15 patients (39.5%) in the failure group. Age, sex, underlying diseases, and SGS severity grade were not significantly different between two groups. In patients who had multiple endoscopic procedures, the failure group showed SGS deteriorated after procedures in 66.7%, compared to 11.1% of the success group. In multivariable analysis, a long-term intubation (≥1 month) was identified as an independent risk factor for failure of endoscopic dilation procedure. Conclusion Although endoscopic dilation procedure is safe and effective for the management, repetitive endoscopic dilation may not give clinical benefit in patient with long-term intubation. Other airway procedures must be considered in those group of patients.

The Effects of the Residual Ba and Zr on the Acid Pickling in Case of the Recovering of Zr in Pickling Waste Acid through the BaF2 Precipitation Process (BaF2 침전 공정을 통한 폐산세정액 내 Zr 회수 시 잔존 Ba 및 Zr이 산세정에 미치는 영향)

  • An, Chang Mo;Choi, Jeong Hun;Han, Seul Ki;Park, Chul Ho;Kahng, Jong Won;Lee, Young Jun;Lee, Jong Hyeon
    • Resources Recycling
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    • v.26 no.5
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    • pp.97-104
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    • 2017
  • Nuclear fuel cladding tubes are manufactured through pilgering and the annealing process. In order to remove the oxidized layer and impurities on the surface of the tube, a pickling process is required. Zirconium (Zr) is dissolved in a HF and $HNO_3$ acid mixture during the process and the pickling waste acid, including the dissolved Zr, is completely discarded after neutralization. This study observes the effects of the residual impurities (Ba) in the pickling solution regenerated from the $BaF_2$ precipitation process on the waste pickling solution. In addition, the concentration of Ba and Zr for the actual nuclear fuel cladding tube process was optimized. The regenerated pickling solution was tested through a pilot plant pickling process device that simulates the commercial pickling process of nuclear fuel cladding tubes, and the pickling efficiency was analyzed through AFM analysis of the roughness of the cladding tube surface.

Development of a Rapid Automated Fluorescent Lateral Flow Immunoassay to Detect Hepatitis B Surface Antigen (HBsAg), Antibody to HBsAg, and Antibody to Hepatitis C

  • Ryu, Ji Hyeong;Kwon, Minsuk;Moon, Joung-Dae;Hwang, Min-Woong;Lee, Jeong-Min;Park, Ki-Hyun;Yun, So Jeong;Bae, Hyun Jin;Choi, Aeran;Lee, Hyeyoung;Jung, Bongsu;Jeong, Juhee;Han, Kyungja;Kim, Yonggoo;Oh, Eun-Jee
    • Annals of Laboratory Medicine
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    • v.38 no.6
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    • pp.578-584
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    • 2018
  • Background: Accurate, rapid, and cost-effective screening tests for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection may be useful in laboratories that cannot afford automated chemiluminescent immunoassays (CLIAs). We evaluated the diagnostic performance of a novel rapid automated fluorescent lateral flow immunoassay (LFIA). Methods: A fluorescent LFIA using a small bench-top fluorescence reader, Automated Fluorescent Immunoassay System (AFIAS; Boditech Med Inc., Chuncheon, Korea), was developed for qualitative detection of hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), and antibody to HCV (anti-HCV) within 20 minutes. We compared the diagnostic performance of AFIAS with that of automated CLIAs-Elecsys (Roche Diagnostics GmbH, Penzberg, Germany) and ARCHITECT (Abbott Laboratories, Abbott Park, IL, USA)-using 20 seroconversion panels and 3,500 clinical serum samples. Results: Evaluation with the seroconversion panels demonstrated that AFIAS had adequate sensitivity for HBsAg and anti-HCV detection. From the clinical samples, AFIAS sensitivity and specificity were 99.8% and 99.3% for the HBsAg test, 100.0% and 100.0% for the anti-HBs test, and 98.8% and 99.1% for the anti-HCV test, respectively. Its agreement rates with the Elecsys HBsAg, anti-HBs, and anti-HCV detection assays were 99.4%, 100.0%, and 99.0%, respectively. AFIAS detected all samples with HBsAg genotypes A-F and H and anti-HCV genotypes 1, 1a, 1b, 2a, 2b, 4, and 6. Cross-reactivity with other infections was not observed. Conclusions: The AFIAS HBsAg, anti-HBs, and anti-HCV tests demonstrated diagnostic performance equivalent to current automated CLIAs. AFIAS could be used for a large-scale HBV or HCV screening in low-resource laboratories or low-to middle-income areas.