• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.469-475
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• 2020

During meiosis I, programmed DNA double-strand breaks (DSBs) occur to promote chromosome pairing and recombination between homologs. In Saccharomyces cerevisiae, Mec1 and Tel1, the orthologs of human ATR and ATM, respectively, regulate events upstream of the cell cycle checkpoint to initiate DNA repair. Tel1^ATM and Mec1^ATR are required for phosphorylating various meiotic proteins during recombination. This study aimed to investigate the role of Tel1^ATM and Mec1^ATR in meiotic prophase via physical analysis of recombination. Tel1^ATM cooperated with Mec1^ATR to mediate DSB-to-single end invasion transition, but negatively regulated DSB formation. Furthermore, Mec1^ATR was required for the formation of interhomolog joint molecules from early prophase, thus establishing a recombination partner choice. Moreover, Mec1^ATR specifically promoted crossover-fated DSB repair. Together, these results suggest that Tel1^ATM and Mec1^ATR function redundantly or independently in all post-DSB stages.

• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3541-3546
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• 2014

TEL-AML1 fusion oncogene (t 12; 21) is the most common chromosomal abnormality in childhood acute lymphoblastic leukemia (ALL). This translocation is associated with a good prognosis and rarely shows chemotherapeutic resistance to 3-drug based remission induction phase of treatment as well as overall treatment. Thus, the higher the frequency of this fusion oncogene, the easier to manage childhood ALL in a given region with less intensive chemotherapy. Although global frequency of TEL-AML1 has been reported to be 20-30%, a very low frequency has been found in some geographical regions, including one study from Lahore, Punjab, Pakistan and others from India. The objective of present study was to investigate if this low frequency of TEL-AML1 in pediatric ALL is only in Lahore region or similar situation exists at other representative oncology centers of Pakistan. A total of 167 pediatric ALL patients were recruited from major pediatric oncology centers situated in Lahore, Faisalabad, Peshawar and Islamabad. Patients were tested for TEL-AML1 using nested reverse transcription polymerase chain reaction (RT-PCR). Only 17 out of 167 (10.2%) patients were found to be TEL-AML1 positive. TEL-AML1+ALL patients had favorable prognosis, most of them (82.4%, 14/17) showing early remission and good overall survival. Thus, our findings indicate an overall low frequency of TEL-AML1 in Pakistan pediatric ALL patients, in accordance with lower representation of this prognostically important genetic abnormality in other less developed countries, specifically in south Asia, thus associating it with poor living standards in these ethnic groups. It also indicates ethnic and geographical differences in the distribution of this prognostically important genetic abnormality among childhood ALL patients, which may have a significant bearing on ALL management strategies in different parts of the world.

• Clinical Endoscopy
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• 제56권2호
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• pp.188-193
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• 2023

Background/Aims: Data on the incidence of adverse respiratory events during recovery from gastrointestinal endoscopy are limited. The aim of this study was to investigate the incidence of these complications. Methods: In this retrospective cohort study, data were obtained from the electronic records of 657 consecutive patients, who underwent gastroenterological procedures under sedation. Results: Pulse oximetry oxygen saturation (SpO₂) <90% for <60 seconds occurred in 82 patients (12.5%), and in 11 patients (1.7%), SpO₂ of <90% for >60 seconds occurred in 79 patients (12.0%) and in 14 patients (2.1%), and SpO₂ <75% occurred in four patients (0.6%) and in no patients during the procedure and recovery period, respectively. No major complications were noted. The occurrence of desaturation during recovery was correlated with desaturation during the procedure (p<0.001). Higher American Society of Anesthesiologists score (odds ratio [OR], 1.867; 95% confidence interval [CI], 1.008-3.458), ischemic heart disease (OR, 1.815; 95% CI, 0.649-5.080), hypertension (OR, 1.289; 95% CI, 0.472-3.516), and diabetes mellitus (OR, 2.406; 95% CI, 0.950-6.095) increased the occurrence of desaturation during recovery. Conclusions: We found no major complications during recovery after balanced propofol-based sedation administered by a gastroenterologist-nurse team. Patients with the identified risk predictors must be monitored carefully.

• International Journal of Stem Cells
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• 제16권2호
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• pp.244-249
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• 2023

Background and Objectives: To examine whether ischemic retinal ganglion cells (RGCs) will be salvaged from cell death by human adipose-derived mesenchymal stem cells (ADSCs) in an organotypic retina model. Methods and Results: Deprived of arterial oxygen supply, whole mice retinas were cultured as an ex vivo organotypic cultures on an insert membrane in a 24-well plate. The therapeutic potential of ADSCs was examined by co-culture with organotypic retinas. ADSCs were seeded on top of the RGCs allowing direct contact, or at the bottom of the well, sharing the same culture media and allowing a paracrine activity. The number of surviving RGCs was assessed using Brn3a staining and confocal microscopy. Cytokine secretion of ADSCs to medium was analyzed by cytokine array. When co-cultured with ADSCs, the number of surviving RGCs was similarly significantly higher in both treatment groups compared to controls. Analysis of ADSCs cytokines secretion profile, showed secretion of anti-apoptotic and pro-proliferative cytokines (threshold>1.4). Transplantation of ADSCs in a co-culture system with organotypic ischemic retinas resulted in RGCs recovery. Since there was no advantage to direct contact of ADSCs with RGCs, the beneficial effect seen may be related to paracrine activity of ADSCs. Conclusions: These data correlated with secretion profile of ADSCs' anti-apoptotic and pro-proliferative cytokines.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.73.1-73.1
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• 2008

• 대한치과교정학회지
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• 제53권1호
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• pp.45-53
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• 2023

Objective: This study aimed to evaluate the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensionally (3D)-printed materials after various surface treatments and artificial aging compared with that bonded to computer-aided design/computer-aided manufacturing (CAD-CAM) polymethyl methacrylate (PMMA)-milled materials. Methods: Eighty cylindrical specimens were 3D printed and divided into the following four subgroups (n = 20 each) according to the surface treatment and artificial aging procedure. Group A, sandblasted with 50 ㎛ aluminum oxide particles (SA) and aging; group B, sandblasted with 30 ㎛ silica-coated alumina particles (CO) and aging; group C, SA without aging; and group D, CO without aging. For the control group, 20 CAD-CAM PMMA-milled cylindrical specimens were sandblasted with SA and aged. The SBS was measured using a universal testing machine (0.25 mm/min), examined at ×2.5 magnification for failure mode classification, and statistically analyzed (p = 0.05). Results: The retention obtained with the 3D-printed materials (groups A-D) was higher than that obtained with the PMMA-milled materials (control group). However, no significant difference was found between the study and control groups, except for group C (SA without aging), which showed significantly higher retention than the control group (PMMA-SA and thermocycling) (p = 0.037). Study groups A-D predominantly exhibited a cohesive specimen mode, indicating specimen fracture. Conclusions: Orthodontic brackets bonded to 3D-printed materials exhibit acceptable bonding strengths. However, 3D-printed materials are prone to cohesive failure, which may result in crown fractures.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.492-495
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• 1995

A simple method to design observers for linear describtor systems with unmeasureable disturbance is represented by the response of a linear free system. The sufficient conditions for the existence of the observer are given. The design procedures of an identify and a minimal order observers are shown, respectively.

• 한국전자파학회논문지
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• 제15권10호
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• pp.915-921
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• 2004

본 논문에서는 안테나 방사부를 톱날의 모노폴 구조를 가지면서 이면(裏面)의 접지 면적을 변화시키는 임피던스 정합 방법을 적용하여 광대역 특성을 갖는 안테나를 제안한다. 제안된 안테나의 길이는 1/4 파장보다 작고, 대역폭은 2:1 VSWR의 범위에서 $89.6\%$, 0.8 GHz$\~$2.0 GHz에서의 안테나 이득은 -0.02 dBi$\~$2.54 dBi를 얻었으며 방사패턴은 모노폴 안테나와 유사한 패턴을 얻을 수 있었다.

• 천문학회지
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• 제29권spc1호
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• pp.421-423
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• 1996

• 정보기술과데이타베이스저널
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• 제1권2호
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• pp.71-102
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• 1994

현대는 고도 정보화사회(information society)로서 DB의 가치는 점점 증가하고 전반적인 DB 서비스는 일반적으로 많이 발전하여 우수한 정보 서비스가 제공되고 있다. 그러나 관광정보 DB서비스의 가치는 아직까지 거의 인식되지 않고 있는 실정이다. 따라서 본 연구에서는 초보단계에 있는 관광정보 DB서비스의 만족도를 측정함으로써 국내 관광정보 DB서비스의 수준을 파악하고 관광정보제공자에게 개선해야 될 문제점을 제시하고자 한다. 그러므로 관광정보 DB서비스의 개념을 정립하고 관광정보 DB서비스의 현황을 고찰하고자 Bailey와 Pearson의 연구에서 제시한 39가지 요인 중에서 관광정보 DB서비스와 관련된 요인을 추출하고 의미를 재정의하여 HiTEL의 이용자를 대상으로 첫째, 정보서비스의 메뉴별 선호도 둘째, 관광정보 DB서비스의 만족도 셋째, 관광정보 DB서비스의 각 메뉴별 선호도와 만족도 넷째, 이용자 특성별로 각 메뉴의 선호도를 비교분석 다섯째, 관광정보 DB서비스의 만족요인을 분석하였다. 관광정보 DB서비스의 전반적인 만족도는 평균치(4.0)보다 저조한 3.85로서 저조하게 나타나고 있다. 즉, 관광정보의 이해도(4.55)는 평균보다 다소 좋은 반면, 다른 관광정보의 만족도는 평균치 보다 저조하다. 특히 관광정보의 연결사정(3.68)과 관광정보의 제공속도(3.44)가 아주 낮게 나타났다. 한편 HiTEL이 제공하는 관광정보 DB서비스의 각 메뉴 중에서 가장 자주 이용되는 메뉴는 알림나라(40.2%)이며, 아시아나항공(22.5%), 농협일렉트로뱅크(13.7%), 대한항공(9.8%), 위너스 OK서비스(6.9%), MEET/매경SCOUT(6.9%)의 순으로 관광정보는 전반적으로 골고루 이용되고 있다. 또한, 메뉴별 관광정보 DB서비스의 만족도가 평균만족도보다 낮은 것은 알림나라(3.48), 농협일렉트로뱅크(3.84), 대한항공(3.90), 위너스OK서비스(3.95)로 나타났다. 그리고 각 메뉴별 이용자의 계층별 선호도는 첫째, 남성은 알림나라(40%), 아시아나 항공(23.16%), 농협일렉트로뱅크(12.63%)를 많이 이용하나, 여성은 알림나라(42.86%), 농협일렉트로뱅크(28.57%)를 주로 선호하는 것으로 나타났다. 둘째, 연령별 선호도는 나이가 많을수록 단순 관광안내정보인 알림나라, 농협일렉트로뱅크보다는 보다 항공관련 정보를 더욱 선호하는 것으로 나타났다. 셋째, 직업별 선호도는 학생과 사무직에 종사하는 사람이 가장 많은 메뉴를 이용하며, 전문직, 관리직, 기술직은 대체적으로 항공관련정보를 더 선호하는 것으로 분석되었다. 넷째, 학력별 선호도는 고학력자일수록 많은 메뉴를 이용하고 있으며, 다섯째, 가입시기별 선호도는 가입한 시간이 길어짐에 따라 항공관련정보를 선호하는 것으로 나타났다.