• Molecules and Cells
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• 제27권6호
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• pp.689-695
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• 2009

Chemically synthesized small interfering RNAs (siRNAs) can specifically knock-down expression of target genes via RNA interference (RNAi) pathway. To date, the length of synthetic siRNA duplex has been strictly maintained less than 30 bp, because an early study suggested that double-stranded RNAs (dsRNAs) longer than 30 bp could not trigger specific gene silencing due to the induction of non-specific antiviral interferon responses. Contrary to the current belief, here we show that synthetic dsRNA as long as 38 bp can result in specific target gene silencing without non-specific antiviral responses. Using this longer duplex structure, we have generated dsRNAs, which can simultaneously knock-down expression of two target genes (termed as dual-target siRNAs or dsiRNAs). Our results thus demonstrate the structural flexibility of gene silencing siRNAs, and provide a starting point to construct multifunctional RNA structures. The dsiRNAs could be utilized to develop a novel therapeutic gene silencing strategy against diseases with multiple gene alternations such as viral infection and cancer.

• 한국해양공학회지
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• 제1권2호
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• pp.93-100
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• 1987

Corrosion fatigue cracking of the austenitic stainless steel(bese metal & heat affected zone by TIG weld) was studied experimentally under the environments of various specific resistance and air. The characteristics of corrosion fatigue crack growth rate and the environmental constants of paris' rule were investigated for SUS 304 weldments in the various specific resistance. The influences of stress intensity factor range and corrosion on the crack growth rate were compared. The characteristics of corrosion fatigue cracking for the weldments were inspected from mechanical, electrochemical and microstructural point of view. Main results obtained are as follows: 1) As the specific resistance decreases, the environmental constant C of paris'rule increases(hence the corrosion fatigue crack growth rate is rapid), but the environmental constant m decreases, so the effect of corrosion to the crack growth rate is more susceptible than thet of stress intensity factor range. 2) As the stress intensity factor range decreases, the corrosion fatigue crack growth rate of heat affected zone is more susceptible than that of the base metal. 3) The corrosion fatigue crack growth rate of the heat affected zone is more rapid than that of the base metal, because of the phenomenon of softening and the less noble potential coused by wedlding heat cycle. 4) The corrosion fatigue cracking of SUS 304 weldment appears transgranular fracture.

• Journal of Biosystems Engineering
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• 제27권2호
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• pp.143-150
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• 2002

Several researches for site-specific weed control have tried to increase accuracy of weed detection with machine vision technique. However, there is a problem which needs substantial time to perform site-specific spraying. Therefore, new technology for real-time precision spraying system is needed. This research was executed to develope the new technology to estimate weed density and size in real time, and to conduct a real-time site-specific spraying. It would effectively reduce herbicide amounts applied for a crop field. The real-time precision spraying system consisted of a Differential Global Positioning System (DGPS) with an error of 2 cm, a machine vision system, a geomagnetic sensor for correction of view point of CCD camera and an automatic sprayer with separately controlled nozzle. The weed density was calculated with comparison between position information and a pre-designed electronic map. The position information was obtained in real time using the DGPS and the machine vision. The electronic map contained a position database of crops automatically constructed when seeding. The developed system was tested on an experimental field of Seoul National University. Success rate of the spraying was about 61%.

• Asia Marketing Journal
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• 제20권3호
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• pp.39-62
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• 2018

Despite the abundance of research on alcoholic-beverage consumption in the food and beverage marketing literature, research directly assessing and comparing consumers' psychological motives for drinking different types of alcoholic beverages is relatively limited. There is also a paucity of research comparing drink-type specific consumption motivations in an Asian market. Paying attention to some recent new changes in the alcoholic-beverages market of South Korea, this study investigated South Korean young adult female consumers' alcoholic-beverage type-specific drinking motives. A self-administered online survey of 340 young adult female drinkers about their alcohol-consumption patterns, alcoholic-drink preferences, involvement with alcohol, and four types of drinking motives (coping, social, conformity, and enhancement motives) revealed differences in: (1) the association between the consumer's alcohol involvement level, alcohol consumption frequency/amount, and preferences for alcoholic beverages across different types of alcoholic drinks; (2) the underlying psychological motives for drinking different types of alcoholic beverages; (3) the association between consumption contexts and alcoholic drink types; and (4) the consumption patterns and drinking motives across different consumer groups that are segmented in terms of their most preferred type of alcoholic beverages. These findings point to the importance of investigating drink-type-specific consumption motivations in alcoholic-beverage consumption research. Limitations and implications for future research are also discussed.

• Korean Journal of Acupuncture
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• 제21권1호
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• pp.113-127
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• 2004

Objectives : The usage of acupuncture has gained popularity as an alternative method of treatment for certain chronic pain conditions. However, the efficacy of acupuncture in various diseases has not been fully established and the underlying mechanism is not clearly understood. In the present study, the effect of electroacupuncture (EA) applied to foot samli$(ST_{36})$ on the carrageenan-induced knee arthritic pain was examined. Methods : A common source of persistent pain in humans is the knee arthritis. Knee arthritis was induced by injection of 2 % carrageenan $50\;{\mu}l$ into the knee joint cavity. When rats developed pain behaviors, EA was applied for 30 min. under enflurane anesthesia with repeated train stimuli at the intensity of 10X of muscle twitch threshold. The weight bearing force of the hind limb was measured for an indicator of pain level after each manipulation. Results : The average weight borne by the hind limb during normal gait was 55% of total body weight, which was reduced to less than 10% after knee arthritis. EA improved the weight bearing of the arthritic hind limb significantly for the duration of 4 hr. EA applied to $ST_{36}$ point produced a significant improvement of stepping force of the arthritic foot lasting for at least 4 h. However, $GB_{31}$ point did not produce any significant increase of weight bearing force. The analgesic effect was specific to the acupuncture point since the analgesic effect on the knee arthritis model could not be mimicked by EA applied to a nearby point, $GB_{31}$. The relations between EA-induced analgesia and endogenous nitric oxide(NO) and inducible NO synthase(iNOS)/neuronal NOS was also examined. Results were turned out that both NO production and nNOS/iNOS protein expression which is increased by arthritis were suppressed by EA stimulation applied to $ST_{36}$ point. Conclusions : The data suggest 1) that EA produces a potent analgesic effect on the rat model of chronic knee arthritis pain in a point specific manner and 2) that EA-induced analgesia modulate endogenous NO through the suppression of nNOS/iNOS protein expression.

• 연구논문집
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• 통권27호
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• pp.87-99
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• 1997

Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.

• 환경정책연구
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• 제12권2호
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• pp.59-86
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• 2013

1988년부터 2008년까지의 자료를 바탕으로 우리나라 6개 권역을 대상으로 권역별 소득, 환경규제, 오염유발원이 각 권역별 대기오염 물질(황산화물, 질소산화물, 총먼지, 일산화탄소)에 미치는 영향을 지역적 관점에서 살펴보았다. 즉, 환경 쿠즈네츠 곡선(EKC)가설 검증차원에서 공해배출과 경제성장 간의 관계를 패널회귀분석을 통해 분석하였다. 분석 결과, 산업시설에 영향을 미치고 있는 황산화물(SOx)의 경우 대부분의 권역에서 EKC가설이 성립하는 것으로 나타났지만, 질소산화물(NOx)과 총먼지(TSP)의 경우 6개 권역 중 대경권에서만 EKC가설이 성립하는 것으로 나타났 으며, 일산화탄소(CO)의 경우에도 EKC가설을 충족시키는 권역은 중부권, 호남권, 동남권에 한정되어 있었다. 또한 각 권역별 대기오염 단속규제가 대기오염과 정(+)의 관계를 보임에 따라 환경규제효과가 나타난다고 보기 어려우며, 각 권역별 연료소비와 석유화학제품의 특화 또한 권역별 대기오염을 증가시키는 주요 요인으로 작용하고 있다.

• 응용통계연구
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• 제30권4호
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• pp.503-512
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• 2017

선다형 문제의 경우 특정 위치의 답을 선호하는 수험생의 응답경향이 시험 결과에 미치는 영향을 최소화하기 위하여 정답배열을 특정위치에 편중되지 않고 고르게 분포할 필요가 있다. 이는 정답배열이 특정 번호에 편중되어 있으면 정답을 모를 때 중앙 또는 외곽 번호에 응답경향이 있는 수험생이 추측으로 문항의 답을 맞힐 수 있으므로 시험점수가 학생의 능력을 제대로 반영하지 못하는 결과를 초래할 수 있기 때문이다. 본 논문에서는 2017학년도 대학수학능력시험의 영역별 정답배열에 대하여 Bartels rank test, Wald-Wolfowitz runs test, turning point test, Cox Stuart trend test, difference sign test, Mann-Kendall rank test 등을 실시하여 정답배열이 고르게 분포되었는지 확인하였다. 또한 정답 번호와 배점 사이에 독립성이 지켜지지 않을 경우에도 특정 번호를 정답으로 선호하는 경향을 가진 수험생의 점수는 학생의 능력을 제대로 반영하지 못할 수 있기 때문에 정답의 위치와 배점 사이의 독립성 검정을 추가로 실시하였다.

• 대한정형도수물리치료학회지
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• 제29권3호
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• pp.43-53
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• 2023

Background: Patients with neck pain develop instability due to muscle imbalance, decreased proprioception, and balance disorders. Studies have examined various exercise methods as treatment methods, but few studies have compared the effects of cervical stabilization exercise and dynamic balance exercise. The purpose of this study was to investigate the effects of dynamic balance exercise on pain, functional level, and psychosocial level in patients with non-specific chronic neck pain. Methods: Thirty-four non-specific chronic neck pain patients were randomly assigned to the experimental group (EG, n=17) and control group (CG, n=17); the cervical stabilization exercise and dynamic balance exercise program were applied to the EG; and only the cervical stabilization exercise program was applied to the CG. The intervention was conducted twice a week, for six weeks. Assessment items evaluated pain, dysfunction (Korean version neck disability index), range of motion, craniocervical flexion test, cervical deep flexor endurance test, and psychosocial level. Data analysis was performed using intention-to-treat analysis as assigned. To analyze differences in the items assessed in the two groups, we used a repeated measures analysis of variance with an interaction between group (EG, CG) and time point (baseline, 6 weeks, 12 weeks). Results: The endurance of the cervical flexor muscles between the group and the measurement point after intervention (p<.05). Both groups showed significantly improved endurance between time points after the intervention (p<.05), with the EG showing a greater change than the CG. None of the other measurement items differed in the pattern of change between measurement points. Conclusion: In conclusion, the EG applying a cervical stabilization exercise and a dynamic balance exercise experienced a significant difference in muscle endurance improvement compared to the CG. We propose an exercise intervention program that includes stabilization exercises and dynamic balance exercises for patients with chronic cervical pain who lack muscle endurance.

• Asian-Australasian Journal of Animal Sciences
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• 제6권4호
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• pp.497-507
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• 1993

Four truncation selection schemes (SSs) were framed to predict and compare the age structures and genetic responses under the influence of various factor employing the scheme-specific algorithms. Two paths of selection, sires (bulls' sires) and dams (bulls' dams) to breed young bulls were considered. Among variable factors, four levels (0.3, 0.5, 0.7, 0.9) of precision of evaluation, five levels (0.0, 0.05, 0.10, 0.15, 0.20 genetic standard deviation) of genetic differences among age classes and 4 levels of proportions selected (for bulls' sire, 0.05, 0.10, 0.125, 0.25, and for bulls' dams 0.02, 0.04, 0.05, and 0.10) contemplated on both paths of selection. The number of age classes for bulls' dams and bulls' sires were 4 or 8 and 2 or 4, respectively. The stayability across age classes for bulls' dams was assumed to be 0.80 or 0.60. The candidates for selection for bulls' sires were equally distributed (0.5 or 0.25) across the age classes. The SS1 (selection on same proportions as candidates' distribution) revealed longest generation lengths and lowest yearly genetic responses. The average ages were youngest and yearly genetic responses were highest in SS4 (selection at each age-specific truncation point with the same average genetic superiority of selected parents across the ages) and followed by SS3 (selection at each agespecific truncation point with same predicted genetic values) and SS2 (selection at common truncation point on phenotypic values) in a population with overlapping generations. The results revealed the importance of choosing suitable selection scheme to acquire maximum yearly genetic responses especially when the genetic differences among age classes are large and the precision of evaluation is relatively low.