미세 유동장 내 자성에 의한 에이팝토틱 세포 이동성향 분석

손오택(Oh-Taek Son),이창근(Chang-Geun Lee),김현석(Hyun-Seok Kim),이창훈(Chang-Hoon Lee),정효일(Hyo-Il Jung) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

Apoptosis is a programmed cell death and a good indication to check the efficiency of the drug compound as it is the first cellular process in the treatment of tumor with anti-tumor agent. Fast separation of apoptotic cells in microfluidic device can be used in high-throughput screening to monitor the efficiency of drug compounds. Designs for microfluidic device to separate magnetic beads coated apoptotic cells were investigated with computational fluid dynamics analysis. Based on the computer simulation the optimal flow rate of the cell mixture solution were determined in the absence of sheath flow. The separation effect of the apoptotic cells on various number of magnetic beads on the cell surface was studied and a new design of magneto-microfluidic device could be made thereafter.

아미노글리코사이드 사용제한에 따른 병원성 균혈증 유발 그람음성간균의 내성변화 및 임상적 의의

오종택,김신우,손종원,도병훈,한승우,신병철,박지현,이종명,김능수 대한감염학회 2003 감염과 화학요법 Vol.35 No.4

목적 : 항균제 오남용으로 인한 내성균의 출현, 약물부작용의 발생 및 약제 비용의 증가는 환자 개인뿐만 아니라 사회적으로 문제가 되고 있다. 본 연구는 항생제의 오남용을 막기 위한 제도의 일환으로 시행한 아미노글리코사이드 사용 제한정책의 비용 효과적인 측면을 조사하고 그람음성간균에 의해 병원성 균혈증이 발생한 환자들을 대상으로 이 정책이 항생제 내성률과 환자 사망률에 미치는 영향을 연구하였다. 방법 : 930병상 규모의 3차 병원인 일개 대학병원에서 아미노글리코사이드 사용제한정책이 시행된 직후인 2002년 3월에서 9월 사이에 그람음성간균(Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Stenotrophomonas maltophilia, Burkholderia cepacia)에 의해 발생한 병원성 균혈증 환자 60명(실험군)과, 이 정책이 시행되기 전에 입원한 환자들 중 균주별로 같은 수만큼 선별한 병원성 균혈증 환자 60명(대조군)의 의무기록을 후향적으로 조사하였다. 결과 : 아미노글리코사이드 사용제한정책이 시행된 시기인 2002년 3월에서 9월 사이에 처방된 아미노글리코사이드 사용량 및 비용을 이 정책이 시행되기 전인 2001년 3월에서 9월 사이와 비교한 결과, 아미노글리코사이드의 사용량(antimicrobial utilization density)은 사용제한 후 225.2에서 130.3으로 42% 감소하였고 약제 비용은 44% 감소하였다. 아미노글리코사이드 사용제한 후 병원성 균혈증을 유발한 그람 음성간균의 이 항생제에 대한 내성률은 유의한 변화를 보이지 않았으며 균혈증과 직접 연관된 사망률도 환자의 나이, 성별, 기저질환 및 원발병소 등을 보정할 경우 유의한 차이를 보이지 않았다(40.4% vs. 24.1%, P=0.11). 결론 : 아미노글리코사이드를 5일을 초과한 사용 시 감염전문가의 사전 승인을 필요로 하는 사용제한정책은 아미노글리코사이드의 사용량과 비용을 유의하게 감소시켰다. 또한 이 정책 시행 후 그람음성간균에 의한 균혈증 환자에서 균혈증으로 인한 사망률과 아미노글리코사이드에 대한 내성률은 유의한 차이가 없었다. Objective : To evaluate the effects of an aminoglycoside restriction policy on expenditures for aminoglycosides, antimicrobial resistance rates and clinical outcome of nosocomial bacteremia caused by Gram-negative bacilli (GNB). Methods : Starting in February, 2002, a prior consultation with an infectious disease specialist for using aminoglycoside antibiotics over 5 days was required in a 930-bed university hospital. In retrospective analysis of medical records 7 months after initiation of the aminoglycoside restriction policy, sixty cases of clinically relevant nosocomial bacteremia caused by GNB were found. These bacteremic patients were compared with sixty, species-matched, control patients with nosocomial Gramnegative bacteremia before the policy for total expenditures for aminoglycosides, susceptibility to antibiotics and clinical outcomes of bacteremia. Results : During the same period of 7 months before and after the restriction policy, total expenditures for aminoglycosides decreased by 44% in cost (from 465,030,841 Won to 259,618,337 Won) and the antimicrobial utilization density of aminoglycosides decreased by 42% (from 225,2 to 130.3). On the other hand, the patterns of antibiotic susceptibility and bacteremia-related in-hospital mortality rates after the policy did not show a significant change, compared with those before the policy. Conclusion : Antibiotic restrictions are among the most popular methods to diminish the practice of antibiotic overuse in hospitals. In this study, requirement for prior approval of aminoglycoside use over 5 days led to a significant decrease in the amount and cost of total aminoglycosides without a significant change in susceptibility patterns and bacteremia-related mortality rates.

과산화수소의 농도와 적용시간이 상아질의 깊이에 따라 레진 수복물의 미세인장결합강도에 미치는 영향

손정룡,이계영,강유미,오영택,이광원,김태균 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.5

본 연구의 목적은 심부 상아질과 치수실 상아질에 H₂O₂를 각기 다른 적용시간과 농도로 적용하였을 때, 레진수복물과의 미세인장결합강도에 미치는 영향을 평가하는 것이다. 준비된 각각의 치아에 전형적인 근관와동을 형성하고 다음과 같이 무작위로 1개의 대조군과, 4개의 실험군으로 나누었다: 1군, 전처리를 시행하지 않았다; 2군, 20% H₂O₂를 20분, 10분, 5분간 적용하였다; 3군, 10% 를 20분, 10분, 5분간 적용하였다; 4군 5% H₂O₂를 20분, 10분, 5분간 적용하였다; 5군, 2.5% H₂O₂를 20분, 10분, 5분간 적용하였다. 위와 같이 처리한 후 와동 내를 Superbond C&B(Sunmedical, Co., Shiga, Japan)로 충전하였다. 각 치아는 증류수에 24시간 저장한 뒤 심부 상아질과 치수실 상아질로 잘라 미세인장결합강도 시험을 시행하였다. 각 군에서 측정된 미세인장결합강도를 3-way ANOVA와 Tukey post hoc test로 통계 처리하였다(p < 0.05). 실험 결과 모든 군에서 심부 상아질(D1)의 미세인장 결합강도가 치수실 상아질(D2)보다 높게 나타났다. 평균 결합강도는 H₂O₂의 농도와 적용 시간이 증가할수록 감소하였다. 통계분석에서 상아질의 깊이, H₂O₂농도와 적용 시간이라는 세 가지 변수간의 교호작용 효과는 없으나(p > 0.05). 상아질의 깊이와 H₂O₂농도 사이, H₂O₂농도와 적용 시간 사이에서는 교호작용 효과가 있었다(p < 0.05). SEM 관찰에서는 H₂O₂의 농도가 증가할수록 상아세관이 좀 더 개방된 양상을 보였다. The purpose of this study was to examine the effect of hydrogen peroxide at different application time and concentrations on the microtensile bond strength of resin restorations to the deep and the pulp chamber dentin. A conventional endodontic access cavity was prepared in each tooth, and then the teeth were randomly divided into 1 control group and 4 experimental groups as follows: Group 1, non treated; Group 2, with 20% Hydrogen peroxide (H₂O₂); Group 3, with 10% H₂O₂; Group 4, with 5% H₂O₂; Group 5, with 2.5% H₂O₂; the teeth of all groups except group 1 were treated for 20, 10, and 5min. The treated teeth were filled using a Superbond C&B (Sun medical Co., Shiga, Japan). Thereafter, the specimens were stored in distilled water at for 24-hours and then sectioned into the deep and the chamber dentin. The microtensile bond strength values of each group were analyzed by 3-way ANOVA and Tukey post hoc test(p < 0.05). In this study, the microtensile bond strength of the deep dentin (D1) was significantly greater than that of the pulp chamber dentin (D2) in the all groups tested. The average of microtensile bond strength was decreased as the concentration and the application time of H₂O₂ were increased. Analysis showed significant correlation effect not only between the depth of the dentin and the concentration of H₂O₂ but also between the concentration of H₂O₂ and the application time(p < 0.05), while no significant difference existed among these three variables(p > 0.05). The higher H₂O₂ concentration, the more opened dentinal tubules under a scanning electron microscope(SEM) examination.

Measurement of ROM and EMG of Upper Limbs Based on Motion Analysis during Flower Arranging

Son-Sun Lee,Jong-Eun Song,Won-Gyu Yoo,Oh-Yun Kwon,Taek-Young Lee,Ki-Cheol Son,Stanley J. Kays 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Effects of Samarium on Microstructure and Mechanical Properties of Mg-Al-Ca Alloys

Son, Hyeon Taek,Lee, Jae Seol,Kim, Young Kyun,Oh, Ik Hyun,Yoshimi, Kyosuke,Maruyama, Kouichi Scientific.Net 2007 Materials Science Forum Vol.544-545 No.-

<P>As samarium addition was increased, α- Mg matrix morphology was changed from dendritic to equiaxed grains and average value of grain size was decreased from 101.6㎛ to 39.3㎛. Samarium addition to Mg-5Al-3Ca based alloys resulted in the formation of Mg-Al-Sm thernary intermetallic compounds at grain boundarys and α-Mg matrix grains. In these alloys, two kinds of eutectic structure were observed; coarse irregular-shape structure at grain boundary and fine needle-shape structure in the α-Mg matrix grain. It is found that the yield strength and ultimate strength showed the maximum value of 109.1MPa and 139.3 at Mg-5Al-3Ca-2Sm alloy, respectively.</P>

Effects of Temperature Shift Strategies on Human Preproinsulin Production in the Fed-batch Fermentation of Recombinant Escherichia coli

Son, Young-Jin,Park, Kyong-Hee,Lee, Sang-Yong,Oh, Sung-Jin,Kim, Chang-Kyu,Choi, Byoung-Taek,Park, Yong-Cheol,Seo, Jin-Ho Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.5

Preproinsulin is a well-known precursor of human insulin for the regulation of blood glucose levels. In this study, fed-batch fermentations of recombinant Eschericha coli JM109/pPT-MRpi were carried out for the overexpression of human preproinsulin. The expression of human preproinsulin was controlled by the temperature inducible P2 promoter. The time-course profiles of fed-batch fermentation and SDS-PAGE analysis showed that human insulin expression was triggered by a culture temperature change from 30 to $37^{\circ}C$. Fermentation shift strategies, including the multi-step increase of temperature and the modulation of initiation time, were optimized to obtain high titers of cell mass and preproinsulin. The optimized fed-batch fermentation, consisting of a three-step shift of culture temperature from 30 to $37^{\circ}C$ for 2 h, gave the best results of 43.1 g/L of dry cell weight and 33.3% preproinsulin content, which corresponded to 2.0- and 1.2-fold increases, respectively, as compared to those of fed-batch culture at a constant temperature of $37^{\circ}C$.

Microstructure and Mechanical Properties of Mg-Al-Ca-Sm Alloys at High Temperature

Son, Hyeon Taek,Lee, Jae Seol,Hong, Ji Min,Oh, Ik Hyun,Yoshimi, Kyosuke,Maruyama, Kouichi Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.345 No.-

<P>The aims of this research are to investigate the effect of Sm addition in Mg-Al-Ca alloys on microstructure and mechanical properties. Sm addition to Mg-5Al-3Ca based alloys results in the change from dendritic to equiaxed grain morphorlogy and formation of Al-Sm rich itermetallic compounds at grain boundary and α-Mg matrix. And these Al-Sm rich intermetallic compounds were dispersed homogeously and stabilized at high temperature. And maximum yield and ultimate strength value was obtained at Mg-5Al-3Ca-2Sm alloys at elevated temperature because of homogeneous dispersion of stable Al-Sm rich intermetallic compound at high temperature.</P>

Microstructure and Mechanical Properties of Mg-Al-Ca-Nd Alloys Fabricated by Gravity Casting and Extrusion Process

Son, Hyeon-Taek,Lee, Jae-Seol,Oh, Ik-Hyun,Kim, Dae-Guen,Yoshimi, Kyosuke,Maruyama, Kouichi The Japan Institute of Metals 2008 MATERIALS TRANSACTIONS Vol.49 No.5

<P>The as-cast microstructure of Mg-5Al-3Ca-<I>x</I>Nd alloys consists of equiaxed α-Mg matrix, (Mg, Al)<SUB>2</SUB>Ca eutectic phase and Al-Nd rich intermetallic compounds. With the increase of Nd addition, α-Mg matrix morphology was changed from dendritic to equiaxed grains due to suppression of grain growth by formation of homogeneous intermetallic compounds containing Nd dispersed at grain boundary and α-Mg matrix. And the grain size of as-cast alloys was decreased as addition of Nd was increased. This eutectic phase of the extruded alloys was elongated to extrusion direction and size of this phase was redined comparing to that of as-cast alloys because of severe deformation during hot extrusion. Maximum yield and ultimate tensile strength value of the as-extruded alloys was 322 and 335 MPa at Mg-5Al-3Ca-2Nd alloy, respectively.</P>

Microstructure and Thermoelectric Properties of Rapidly Solidified and Hot Pressed N-Type 95% Bi₂Te₃-5%Bi₂Se₃ Alloys

Son, Hyeon Taek,Oh, Ik Hyun,Lee, Jae Seol,Kang, Chang Seog,Cho, Jae Ik,Bae, Jung Chan Trans Tech Publications, Ltd. 2007 Materials science forum Vol.539 No.-

제주바다목장 해역 내 인공 어초군에 서식하는 어류군집의 종조성 및 계절변동

오택윤 ( Taek Yoon Oh ),차형기 ( Hyung Ki Cha ),황철희 ( Cheol Hee Hwang ),남윤주 ( Yoon Joo Nam ),곽석남 ( Seok Nam Gak ),손민호 ( Min Hoo Son ),장대수 ( Dae Soo Jang ) 한국어업기술학회 2010 수산해양기술연구 Vol.46 No.2