• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4683-4688
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• 2012

Aim: To investigate the association of transforming growth factor-beta 1 (TGF-${\beta}1$) C-509T polymorphism and susceptibility to cancer by means of meta-analysis. Methods: An extensive search was performed to identify eligible case-control studies investigating such a link. The strength of the association between TGF-${\beta}1$ C-509T polymorphism and cancer risk was assessed by pooled odds ratios (ORs) and 95%confidence intervals (95%CIs) in fixed or random effects models. Results: 55 published case-control studies with a total number of 21,639 cases and 28,460 controls were included. Overall, there was no association between TGF-${\beta}1$ C-509T and cancer risk in all genetic comparison models (TT vs. CC: OR=1.01, 95%CI=0.89-1.15; T vs. C: OR=1.01, 95%CI=0.94-1.07). However, a stratified analysis by cancer type indicated -509 T allele was significantly associated with decreased risk of colorectal cancer (CRC) (TT vs. CT/CC: OR=0.85, 95%CI=0.76-0.95), especially for Caucasians (TT vs. CT/CC: OR=0.83, 95%CI=0.71-0.98) and for population-based studies (TT vs. CT/CC: OR=0.78, 95%CI=0.68-0.89). Conclusion: This meta-analysis suggested that TGF-${\beta}1$ C-509T polymorphism might contribute to a decreased risk on colorectal cancer susceptibility, especially for Caucasians.

• Steel and Composite Structures
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• 제20권4호
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• pp.731-748
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• 2016

Pile-to-pilecap connection performance is important as Integral abutment bridges (IABs) have no expansion joints and their flexible weak-axis oriented supporting piles take the role of the expansion joint. This connection may govern the bridge strength and the performance against various lateral loads. The intention of this study is to identify crack propagation patterns when the pile-to-pilecap connection is subjected to lateral loadings and to propose novel connections for improved performance under lateral loadings. In this study, eight different types of connections were developed and modeled, using Abaqus 6.12 to evaluate performances. Three types were developed by strengthening the connections using rebar or steel tube: (i) PennDOT specification; (ii) Spiral rebar; and (iii) HSS tube. Other types were developed by softening the connections using shape modifications: (i) cylindrical hole; (ii) reduced flange; (iii) removed flange; (iv) extended hole; and (v) slot hole connection types. The connections using the PennDOT specification, HSS tube, and cylindrical hole were shown to be ineffective in the prevention of cracks, resulting in lower structural capacities under the lateral load compared to other types. The other developed connections successfully delayed or arrested the concrete crack initiations and propagations. Among the successful connection types, the spiral rebar connection allowed a relatively larger reaction force, which can damage the superstructure of the IABs. Other softened connections performed better in terms of minimized reaction forces and crack prevention.

• 한국전기전자재료학회논문지
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• 제33권1호
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• pp.50-55
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• 2020

Porcelain insulators have been used for a long time in 154 kV power transmission lines. They are likely to be exposed to sudden failure because of product deterioration. This study was conducted to evaluate the quality of porcelain insulators. After stresses were applied, the damaged regions of aged insulators were investigated in terms of chemical composition, material structure, and other properties. For porcelain insulators that were in service for a long time, the mechanical failure load was 126 kN, whereas the average mechanical failure load was 167.3 kN for new products. It was also determined that corrosion occurred at the metal pin part due to the penetration of moisture into the gap between the pin and the ceramic. Statistical analyses of failure were performed to identify the portion of the insulators that were broken. Cristobalite porcelain insulators fabricated without alumina additives had a high failure rate of 54% for the porcelain component. In the case of the addition of Alumina (Al₂O₃) to the porcelain insulators to improve the strength of the ceramic component, a more frequent damage rate of the cap and pin of 73.3% and 27%, respectively, was observed. This study reports on the material component of SiO₂ and the percentage of alumina added, with respect to the mechanical properties of porcelain insulators.

• 한국컴퓨터정보학회논문지
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• 제25권1호
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• pp.63-69
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• 2020

본 논문에서는 상대적인 액세스 포인트의 신호 강도에 기초한 랜드마크를 사용하는 실내 위치 추적 기법에 대하여 제안한다. AP 신호의 절댓값은 기존의 실내 위치 추적 기술에 사용되었지만, 측정 기기, 측정 환경, 그리고 측정 시기의 변동으로 인해 달라질 수 있다. 그러나 우리는 특정 장소에서는 AP의 수신 신호 세기의 흐름이 서의 일정한 패턴을 나타낸다는 사실을 알아냈다. 그 특징에 따라, 우리는 AP들 간의 상대적 강도를 파악하고, 그들이 특정 패턴을 보이는 특정 장소를 랜드마크로서 저장한다. 랜드마크 맵 배치가 완료되면, 시스템은 스마트폰의 IMU 센서를 사용하여 사용자의 위치를 계산하고 저장된 랜드마크로 보정한다. 우리의 시스템은 센서만 사용한 기술에 비하여 75.2%의 개선을, 그리고 절댓값으로 선택된 랜드마크를 사용한 기술에 비하여 39.6%의 개선을 보인다.

• 한국지반신소재학회논문집
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• 제16권4호
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• pp.221-230
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• 2017

선행 연구에서 PVP를 이용하여 수용성 폴리머 파우치를 개발하였다. 그러나 개발된 재료의 용융점이 매우 낮아 재료의 성형 시 문제점이 많아 대량생산 시 필요한 성형, 제작이 불가능하였기에 성형성이 우수한 새로운 재료 조합을 이용하여 폴리머 파우치를 개발하였다. 새롭게 선정된 PEG의 수용성 변화 및 지반공동 내 보강 시 파우치의 기계적 물성을 만족해야한다. 따라서 PEG와 LLDPE, TALC 블렌딩 비율에 따른 특성평가를 실시하였는데 각 원료의 비율에 따라 발생하는 성질이 다르기 때문에 실험을 통해 적정 비율을 찾는 것이 중요하기 때문이다. 이러한 블렌딩을 통해 수용성 특성은 유지하며 인장 및 충격강도가 증진된 폴리머 파우치를 개발하였다. 최종 개발된 제품을 이용하여 직접전단 실험을 실시한 결과, 폴리머 파우치의 지반강도 효과를 확인할 수 있었다.

• 한국결정성장학회지
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• 제28권4호
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• pp.175-178
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• 2018

구리 금속은 높은 열전도도로 heat sink 혹은 heat exchanger로 널리 사용되고 있다. 그러나 이에 반하여 낮은 인장강도와 사용온도 한계를 가지고 있다. 따라서 높은 열전도도, 낮은 제작비와 함께 우수한 기계적 특성이 요구된다. 본 연구에서는 이를 위하여 동철합금($Cu_{50}-Fe_{50}$ alloy)를 고주파 가열로를 이용하여 제조하고 그 특성을 조사하였다. 제조된 동철합금은 Cu, ${\alpha}$-Fe, ${\gamma}$-Fe 결정구조를 기진 dendrite 미세구조를 보여주었다. 제조된 동철합금은 XRD, FE-SEM, EDS 및 XRF를 이용하여 결정구조 및 미세구조를 분석하였으며 전력공급 접점용 소재로서의 적합성을 확인하고자 하였다.

• PNF and Movement
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• 제16권2호
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• pp.161-168
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• 2018

Purpose: This study aimed to investigate the effects of postural control exercise on the delayed heart rate increase in heart transplant patients. Methods: The subject was a female heart transplant recipient who had a delayed increase in heart rate during exercise. The intensity of exercise was performed at MBorg level 4. The A-B-A' and A-B-A'-B' designs were used to identify the changes in heart rate during active-assisted exercise, lower limb postural control exercise, and upper limb postural control exercise. Experiments were performed for four weeks. The heart rates at pre- and post-exercise were compared, and the time to reach MBorg 4 was measured. Results: In the active-assisted exercise, the average heart rates at pre- and post-exercise and after 10 min of exercise were 88, 89, and 87.7 bpm, respectively. In the repetitive comparison of pre- and post-exercise in the lower limb postural control exercise, the difference in the mean heart rate was 3.5 and 3 bpm in stable support and 14 and 14.5 bpm in unstable support, respectively. In the repetitive comparison of pre- and post-exercise in the upper limb postural control exercise, the difference in the mean heart rate was 6 and 4 bpm in stable support and 4 and 4.5 bpm in unstable support. The time required to reach MBorg 4 was short when both the upper and lower postural control exercises were performed in an unstable state. Conclusion: We suggest that combining proper postural control exercise with strength exercise and aerobic exercise, among others, may be effective in rehabilitating patients in the recovery stage after a heart transplant.

• Journal of Acupuncture Research
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• 제26권4호
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• pp.11-18
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• 2009

Objectives : The objective of this review was to evaluate clinical trials of warming acupuncture for musculoskeletal pain diseases, to assess the methodologic quality of the trials and determine whether low-quality trials are associated with positive outcomes, to document adverse effects and to identify the effectiveness of the warming acupuncture. Methods : Seven databases and the Journal ZHONGGUO ZHENJIU(中國鍼灸) published between 2004－2008 were searched. Korean and Chinese randomized trials were evaluated for methodologic quality using the modified Jadad scale. Outcome measurements were pain, function and global improvement. The best-evidence synthesis was performed to determine the strength of evidence by control group. Results : Six clinical trials representing 564 patients with musculoskeletal pain diseases were identified. For pain and function, there was moderate evidence that warming acupuncture is more effective than manual acupuncture. For patient global assesment, there was limited evidence that warming acupuncture is more effective than manual acupuncture. However, for function, there was inconclusive evidence that warming acupuncture is more effective than acupuncture with TDP or western medicine or acupoint-injection treatment. Conclusions : The evidence suggests that warming acupuncture is more effective for musculoskeletal pain diseases than manual acupuncture, acupuncture with TDP, western medicine and acupoint-injection treatment. But the evidence is moderate to inclusive due to the low methodologic quality of the trials. Further clinical trials with high methodologic quality is required to investigate the effectiveness of warming acupuncture.

• 대한간호학회지
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• 제33권8호
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• pp.1101-1110
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• 2003

Purpose. The purpose of this study was to identify the stage of change of smoking cessation behavior and investigate factors associated with the stage of smoking cessation behavior according to the transtheoretical model. Methods. The participants, 297 smokers & quitters were selected by a stratified random sampling from 127 high school sophomore students in B city. Data were collected from April 6th to 16th, in 2002 using the structured self-report questionnaire. Results. The subjects were distributed in each stage of change of smoking cessation behavior: there were 46 subjects (15.5%) in precontemplation, 73 subjects (24.6%) in contemplation, 67 subjects(22.3%) in preparation, 56 subjects (18.5%) in action, 55 subjects (18.5%) in maintenance. Compared to the precontemplation and contemplation, people in preparation tended to smoke daily more and smoked for a shorter time, and as precontemplation progressed to the maintenance, past 1 year smoking cessation frequency increased and friends smoking decreased. Smoking onset age was the earliest in preparation, and the latest in maintenance. Helping relationships and self relationships are used a lot in precontemplation and also in contemplation. In preparation, self liberation and helping relationships are used a lot, in action, self liberation and helping relationships, and in maintenance, self liberation and environmental reevaluation. At each stage, the score of negative affect situation was the highest, but the one of negative affect situation, positive social situation, habitual strength, weight control decreased as precontemplation progressed to the maintenance. While the score of social pros and coping pros decreased with increasing stage, the one of cons tended to increase. Through stepwise discriminant analysis, it was found that social pros, smoking onset age, delf-libration were the most influencing powers among factors associated with the stages of smoking cessation behavior. Conclusions. This study suggested that, in developing an effective smoking cessation intervention for adolescents, all the stage of a client's cessation had to be assessed prior to applying intervention programs. In addition, the results of this study will become a pillar of smoking cessation program planning and application.

• Genomics & Informatics
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• 제14권4호
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• pp.216-221
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• 2016

Osteoporotic fractures (OFs) are critical hard outcomes of osteoporosis and are characterized by decreased bone strength induced by low bone density and microarchitectural deterioration in bone tissue. Most OFs cause acute pain, hospitalization, immobilization, and slow recovery in patients and are associated with increased mortality. A variety of genetic studies have suggested associations of genetic variants with the risk of OF. Genome-wide association studies have reported various single-nucleotide polymorphisms and copy number variations (CNVs) in European and Asian populations. To identify CNV regions associated with OF risk, we conducted a genome-wide CNV study in a Korean population. We performed logistic regression analyses in 1,537 Korean subjects (299 OF cases and 1,238 healthy controls) and identified a total of 8 CNV regions significantly associated with OF (p < 0.05). Then, one CNV region located on chromosome 20q13.12 was selected for experimental validation. The selected CNV region was experimentally validated by quantitative polymerase chain reaction. The CNV region of chromosome 20q13.12 is positioned upstream of a family of long non-coding RNAs, LINC01260. Our findings could provide new information on the genetic factors associated with the risk of OF.