설측브라켓 부착시 위치오차에 관한 연구

최준규,황현식,김종철 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.1

본 연구는 설측브라켓 부착시 부착방법에 따른 위치오차를 알아보기 위하여 시행되었다. 교정환자 20명의 초진시 석고모형을 연구대상으로 하여, 초진모형의 각 치면에 긴밀하게 브라켓을 부착하는 방법, 치아재배열을 시행한 후 치면에 긴밀하게 부착하는 방법 그리고 치아재배열을 시행하고 이상호선을 제작한 후 브라켓을 결찰하여 부착하는 passive bracketing의 3가지 방법으로 브라켓을 부착한 후 각 방법으로 부착된 브라켓의 위치오차를 측정 및 비교하여 다음과 같은 결과를 얻었다. 1. 각도오차 분석결과, 치아재배열을 시행하지 않은 경우 상악 제1소구치와 하악견치의 위치오차가 타 방법에 비하여 크게 나타났으며, passive bracketing을 시행하지 않은 경우 상악 중절치, 하악 제1·제2소구치에서 그 위치오차가 크게 나타났다. 2. 토크오차 분석결과, 치아재배열을 시행하지 않은 경우 하악 제2소구치의 위치오차가 타 방법에 비해 크게 나타났으며 passive bracketing을 시행하지 않은 경우 상악 전 치아와 하악 제1·제2소구치에서 그 위치오차가 크게 나타났다. 3. 회전오차 분석결과, passive bracketing을 시행하지 않은 경우 상악 중절치간, 하악 중절치간, 하악 측절치와 중절치사이 그리고 하악 견치와 측절치 사이에서 그 위치오차가 크게 나타났다. 4. 내외오차 분석결과, passive bracketing을 시행하지 않은 경우 상악 견치와 측절치 사이에서 위치오차가 타 방법에 비해 크게 나타났으며, passive bracketing을 시행하지 않은 경우 상악 중절치간, 측절치와 중절치 사이, 제1·제2소구치사이, 하악 측절치와 중절치 사이, 견치와 측절치 사이에서 그 위치오차가 크게 나타났다. 본 연구 결과는 설측교정술의 경우 브라켓 간접부착 술식을 사용하더라도 상당량의 위치오차가 나타나며, 이는 passive bracketing으로 줄일 수 있음을 시사하였다. The purpose of this study was to evaluate the positioning errors according to the method of bonding lingual brackets. Dental models of twenty orthodontic patients with malocclusion were selected for this study. The positioning errors were measured on each model that brackets were bonded to. Three different bonding methods were used. For the first method, the bracket was bonded intimately to the lingual surface of the model. For the second method, the bracket was bonded intimately to the lingual surface after setting up using articulator. The passive bracketing, bonding the bracket ligated first to ideal archwire, was used after setting up as the last method. The results were as follows: 1. The brackets bonded without setting up showed greater angulation errors in the upper 1st premolar and the lower canine than those in other bonding methods. The brackets bonded without passive bracketing showed greater positioning errors in upper central incisor, lower 1st and 2nd premolars. 2. The brackets bonded without setting up showed greater torque error in lower 2nd premolar than those in other bonding methods. The brackets bonded without passive bracketing showed greater torque errors in all upper teeth, lower 1st and 2nd premolars. 3. The brackets bonded without passive bracketing showed greater rotation errors between upper central incisors, lower central incisors, lower lateral and central incisor, lower canine and lateral incisor. 4. The brackets bonded without setting up showed greater in-out errors between upper canine and lateral incisor than those in other bonding methods. The brackets bonded without passive bracketing showed greater in-out errors between upper central incisors upper central and lateral incisors, upper 1st and 2nd premolars, lower lateral and central incisors, lower canine and lateral incisor. These results suggest that there is a large amount of positioning error in lingual brackets even by an indirect bonding technique, and it may be reduced by passive bracketing.

Inhibition of oxidative stress induced‑cytotoxicity by coptisine in V79‑4 Chinese hamster lung fibroblasts through the induction of Nrf‑2 mediated HO‑1 expression

Hyeon‑Gyun Jo,Cheol Park,이혜숙,Gi‑Young Kim,Young‑Sam Keum,Jin Won Hyun,Taeg Kyu Kwon,Yung Hyun Choi,Su Hyun Hong 한국유전학회 2021 Genes & Genomics Vol.43 No.1

Background Coptisine is a natural alkaloid compound and is known to have multiple benefcial efects including antioxidant activity. However, whether it can protect lung fbroblasts from oxidative damage has not been studied yet. Objectives To investigate the potential inhibitory efect of coptisine against oxidative stress in V79-4 lung fbroblast cells. Methods V79-4 cells were treated with H2O2 (1 mM) in the presence or absence of coptisine (50 µg/ml), N-acetyl cysteine (NAC, 10 mM) or zinc protoporphyrin IX (ZnPP, 10 µM) for the indicated times. The alleviating efects of coptisine on cytotoxicity, cell cycle arrest, apoptosis, reactive oxygen species (ROS) production, DNA damage, mitochondrial dynamics, and inhibition of ATP production against H2O2 were investigated. Western blot analysis was used to analyze the expression levels of specifc proteins. Results Coptisine inhibited H2O2-induced cytotoxicity and DNA damage by blocking abnormal ROS generation. H2O2 treatment caused cell cycle arrest at the G2/M phase accompanied by increased expression of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1 and decreased expression of cyclin B1 and cyclin A. However, these efects were attenuated in the presence of coptisine or NAC. Coptisine also prevented apoptosis by decreasing the rate of Bax/Bcl-2 expression in H2O2-stimulated cells and suppressing the loss of mitochondrial membrane potential and the cytosolic release of cytochrome c. In addition, the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was markedly promoted by coptisine in the presence of H2O2. However, zinc protoporphyrin IX, a potent inhibitor of HO-1, attenuated the ROS scavenging and anti-apoptotic efects of coptisine. Conclusions Based on current data, we suggest that coptisine can be used as a potential treatment for oxidative stress-related lung disease.

TiN 코팅이 전기도금한 교정용 스테인레스스틸 선재의 세포독성에 미치는 영향

최준규,조진형,황현식,박병주 전남대학교 치의학연구소 2003 구강과학 Vol.15 No.4

This study was performed to investigate whether TiN coating could reduce the cytotoxicity of electroplated orthodontic stainless steel wire which had been known to be cytotoxic. Nickel plating was done on stainless steel wire using a electroplating technique. Some of the electroplated wires were coated by TiN film and 4 groups of specimen were prepared (Non-coated electroplated wire, TiN coated electroplated wire, Titanium which was known to have no cytotoxicity, Copper which was known to have high cytotoxicity). Each wire was incubated for 72 hours on the medium. The release of the metal ion was measured by ICP-AES. The incubated medium was diluted 75 %, 50%, 25 % and added on each microplate with Balb/c 3T3 mouse fibroblast for MTT analysis and compared with medium only. Through the measuring of the change in absorbency value of each wire group and the difference of absorbency value according to change of dilution, following results were obtained. 1. The results of ICP-AES analysis showed that lots of nickel ions were isolated from non-coated wires but not isolated from TiN coated wires. 2. The inverted microscope showed that there was a decrease in cell count in non-coated wires but no significant change in TiN coated wires. 3. The results of MTT analysis showed that there was no difference in the absorbency value between TiN coated wires and medium and between titanium and medium but the absorbency value of non-coated wires and copper were lower than that of medium only at all dilution and showed statistically significant differences(p<0.001). 4. Assessment as per ISO 10993, part 5, non-coated wires and copper investigated corresponded to "moderately cytotoxic" and "highly cytotoxic" ; whereas titanium and TiN coated wires were alloted to "non-cytotoxic". The results of the present study indicate that the cytotoxicity of the electroplated orthodontic wire can be changed from "moderately cytotoxic" to "nontoxic" by TiN coating and electroplated wire can be used clinically without the concern of cytotoxicity.

설측브라켓 부착시 위치오차에 관한 연구

최준규,황현식 전남대학교 치과대학 1996 전남치대논문집 Vol.8 No.1

The purpose of this study was to evaluate the positioning errors according to the method of bonding lingual brackets. Dental models of twenty orthodontic patients with malocclusion were selected for this study. The positioning errors were measured on each model that brackets were bonded to . Three different bonding methods were used. For the first method, the bracket was bonded intimately to the lingual surface of the model. For the second method, the bracket was bonded intimately to the lingual surface after setting up using articulator. The passive bracketing, bonding the bracket ligated first to ideal archwire, was used after setting up as the last method. The results were as follows : 1. The brackets bonded without setting up showed greater angulation errors in the upper 1st premolar and the lower canine than those in other bonding methods. The brackets bonded without passive bracketing showed greater positioning errors in upper central incisor, lower 1st and 2nd premolars. 2. The brackets bonded without setting up showed greater torque error in lower 2nd premolar than those in other bonding methods. The brackets bonded without passive bracketing showed greater torque errors in all upper teeth, lower 1st and 2nd premolars. 3. The brackets bonded without passive bracketing showed greater rotation errors between upper central incisors, lower central incisors, lower lateral and central incisor, lower canine and lateral incisor. 4. The brackets bonded without setting up showed greater in-out errors between upper canine and lateral incisor than those in other bonding methods. The brackets bonded without passive bracketing showed greater in-out errors between upper central incisors, upper central and lateral incisors, upper 1st and 2nd premolars, lower lateral and central incisors, lower canine and lateral incisor. These results suggest that there is a large amount of positioning error in lingual brackets even by an indirect bonding technique, and it may be reduced by passive bracketing.

흰쥐 경동맥 손상 모형에서 체외 방사선조사에 의한 신내막 과증식억제 : Intercellular Adhesion Molecule-1과 Vascular cell Adhesion Molecule-1의 역할 The Possible Role of Intercellular Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1

강동헌,승기배,장기육,임상현,정해억,임효영,김연실,채장성,김재형,홍순조,최규보 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.9

브루셀라균에 노출된 미생물 검사실 직원들에 대한 예방적 항생제 요법과 혈청학적 추적검사

이창섭,이혜수,이재현,박진희,최영실,황규잠,이흥범 대한감염학회 2008 감염과 화학요법 Vol.40 No.2

The aerozolization is one of possible Brucella transmission mechanisms, particularly in air-borne exposed laboratory workers. In this study, seven laboratory workers were potentially exposed to B. abortus via aerosols. Two laboratory workers who sniffed an agar plate several times were considered to be at high risk for acquiring the disease, 5 workers who did not work directly with the strain were be considered at low risk of infection. Prophylactic antibiotics of doxycycline 200 mg/day and rifampin 600 mg/day were offered for 6 weeks in high risk workers and 3 weeks for low risk workers respectively. Enrolled workers were advised to check for serological testing of Brucella species every 3 weeks during a total period of 12 weeks. Compliance with taking medicine was 57.1% (4/7) and compliance for completing the serological tests was 85.7% (6/7). None of the laboratory workers developed clinical disease or tested positive serologically during 3 months of seroloaical testing and 1 year of clinical follow-up.

Required Mowing Power and Bale Density of Miscanthus × Giganteus for Field Biomass Harvesting using Different Methods

( Hyeon Jong Jun ),( Il Su Choi ),( Tae Gyoung Kang ),( Yong Choi ),( Duck Kyu Choi ),( Choung Keun Lee ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4

This study investigated the harvesting properties of the giant miscanthus (Miscanthus × giganteus) to measure the required mowing power for different stem conditioning methods in order to shorten the drying time after mowing and the bale density so that the crop can be used as biomass in the winter season. Methods: The required mowing power and bale density were measured using a power measurement device, three different mower-conditioners, and a mid-sized round baler under different working speeds and conditioning methods. Results: For the various mower-conditioners, the average stem length from mowing was 0.86.0.91 m, and the available working speed was 1.6 m/s. The steel roller-type mower- conditioner showed better stem conditioning but could not mow over a working speed of 1.6 m/s. The required average power of the mower-conditioners varied from 23.8 kW for the steel roller-type rotary disk mower-conditioner with a working width of 2.4 m to 37.2 kW for the flail-type rotary disk mower-conditioner with a working width of 3.2 m at a working speed of 1.6 m/s. The bale densities were 155.8.172.2 kg/m3. The highest bale density was measured for stems with no conditioning and a moisture content of 11.3% (d.b.) mowed by the rotary disk mower. The bale density was affected by the mowing method because of the low moisture content of the miscanthus stems. Conclusions: In terms of the working performance and conditioning statue, the steel roller-type mower-conditioner is a better choice at a working width of 2.4 m, while the flail finger-type mower-conditioner is better at a working

Nanogenerators: Fully Rollable Transparent Nanogenerators Based on Graphene Electrodes (Adv. Mater. 19/2010)

Choi, Dukhyun,Choi, Min-Yeol,Choi, Won Mook,Shin, Hyeon-Jin,Park, Hyun-Kyu,Seo, Ju-Seok,Park, Jongbong,Yoon, Seon-Mi,Chae, Seung Jin,Lee, Young Hee,Kim, Sang-Woo,Choi, Jae-Young,Lee, Sang Yoon,Kim, Jo WILEY-VCH Verlag 2010 ADVANCED MATERIALS Vol.22 No.19

<B>Graphic Abstract</B> <P>The cover shows an image of fully rollable transparent nanogenerators synthesized using chemical vapor deposition grown large-scale graphene sheets as transparent electrodes and piezoelectric ZnO nanorod arrays. Sang-Woo Kim, Jae-Young Choi, and co-workers report on p. 2187 the electrical and structural stability of the nanogenerators, with excellent charge scavenging performance under external mechanical loads such as bending and rolling. This study shows that graphene-based nanogenerators are very promising for self-powered rollable transparent device applications. <img src='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content.gif' alt='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content'> </P>

Study on Performance Improvement of a Head-Feeding Rice Combine for Foxtail Millet Harvesting

( Hyeon Jong Jun ),( Il Su Choi ),( Tae Gyoung Kang ),( Yong Choi ),( Duck Kyu Choi ),( Choung Keun Lee ) 한국농업기계학회 2015 바이오시스템공학 Vol.40 No.1

Purpose: The study was conducted to investigate the proper working conditions like the mesh size of the concave and the chaffer angle of the oscillating sieve, and the fan speed of the head-feeding rice combine for foxtail millet harvesting. Methods: The study aimed to determine the harvesting conditions for the rice combine harvester at a 0.5 m/s working speed and at 40° and 55° sieve chaffer angles. The harvesting loss of the foxtail millet based on the speed of the fan and the oscillating speed of the sieve was measured at three levels of fan speed and oscillating sieve speed. Results: The threshing rates of different foxtail millet varieties were 64.1~83.5% at a mesh size of 7 mm of the concave. In experimental foxtail millet harvesting, the optimal operating condition of the rice combine harvester included a 40° sieve chaffer angle and a 4.8Hz oscillating sieve (cleaning shoe) frequency. The grain loss was found to be lower at a 40° than at a 55° sieve chaffer angle. In field harvesting using the combine harvester, the lowest harvesting grain loss rate of the foxtail millet varieties ranged between 0.2~0.5% at a 7 mm mesh concave, 40° chaffer angle, 4.8 Hz sieve frequency, and a 20 m/s fan speed at an engine speed of 2,000 revolutions per minute (RPM). Conclusions: Findings showed that foxtail millet could be harvested using the combine harvester.

Sorghum Harvesting Using a Head-feeding Type Rice Combine

( Hyeon Jong Jun ),( Il Su Choi ),( Tae Gyoung Kang ),( Yong Choi ),( Duck Kyu Choi ),( Choung Keun Lee ),( Sang Hun Kim ) 한국농업기계학회 2018 바이오시스템공학 Vol.43 No.4

Purpose: The aim of this study was to determine appropriate threshing and selection conditions for sorghum harvesting using a rice combine-harvester. Methods: Sorghum harvesting performance was tested using an actual rice combine. Through this test, the grain loss rate and the composition of crops according to the engine and fan speeds of the combine were investigated. Furthermore, the optimal threshing and selection conditions were determined by carrying out a harvest test based on the opening size factor of the concave in a test field. Results: The grain loss rate for the sorghum using a concave (18×18 mm) of the rice combine was the lowest at 0.1% at a chaffer angle of 40°, engine speed of 2000 rpm, and fan speed of 20 m/s, but the sorting sieve clogged frequently. Furthermore, as the engine speed and fan speed increased, the grain loss rate also increased. The sorghum harvesting test results of the combine according to the concave opening size showed that the grain loss rate was 0.5% at a driving speed of 0.5 m/s, with a concave opening diameter of 13 mm, a chaffer angle of 40°, a concave sieve oscillation frequency of 4.8 Hz, a fan speed of 20 m/s, and an engine speed of 2000 rpm. Conclusions: Findings showed that sorghum could be harvested using a head feeding rice combine.