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        검색결과 283

        221.
        2019.10 서비스 종료(열람 제한)
        Central precocious puberty (CPP) is less common in boys than girls; very little data is reported on effect of gonadotropin-releasing hormone analog (GnRHa) treatment in boys with CPP. The aim of the study was to evaluate growth changes in boys with CPP and early puberty (EP) treated with GnRHa therapy for 1 year. In 60 (39 CPP and 21 EP) boys with confirmed diagnosis of CPP and EP, auxological [height, height standard deviation score (Ht SDS), bone age (BA), Predicted adult height (PAH)] and endocrinological parameters were obtained at baseline, at 6 months, and at 1 year after GnRHa treatment in boys with CPP and EP. During the treatment a decline in Ht SDS and growth velocity, luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone levels were observed (p<0.01); and a deceleration in the maturation of bones after 1 year GnRHa treatment was observed (p<0.01). PAH SDS was increased during treatment with GnRHa (p<0.01). There was significant difference in PAH SDS between organic CPP and non-organic CPP (p<0.05). The present data indicate that GnRHa therapy significantly improves growth prognosis in boys with CPP and EP.
        222.
        2019.10 서비스 종료(열람 제한)
        교량의 정밀안전진단시 고유진동수의 추출은 반드시 필요하다. 교량의 고유진동수 추출을 위해서 일반 진단 실무에서는 동재하실험을 실시된다. 그러나 교량의 가진신호 계측이 어려워, 응답만으로 고유진동수를 추출하여야 한다. 차량의 중량이 교량의 중량 대비 매우 작은 경우에 문제가 없으나, 차량의 중량이 무시 못할 정도로 큰 경우에는 차량 주행에 따른 가진 주파수가 응답스펙트럼에 나타나고, 진단 실무자는 종종 가진 모드를 교량의 1차 모드로 오인하는 경우가 적지 않다. 본 연 구는 교량의 고유진동수와 차량의 가진모드를 쉽게 구별할 수 있는 실무적인 방법을 제안한다.
        223.
        2019.02 KCI 등재 서비스 종료(열람 제한)
        Curcumin (C21H20O6) is a hydrophobic polyphenol found in turmeric. Although curcumin has been used as a natural medicine, its major limitation is related to poor absorption from the gut. Therefore, we developed a method for preparation of Curcumin Nanospheres (CN) to improve the aqueous-phase solubility of curcumin and investigate the functional role of CN in promoting feed efficiency and odor reduction in mice. CN showed inhibitory effects on actate dehydrogenase (LDH) cytotoxicity induced by ecotoxic substance toluene in gut epithelial HCT116 cells. In addition, the weights of internal organs (liver, heart, kidneys, and spleen) and the levels of serum Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), and LDH did not show significant differences between mice administered oral CN for two weeks and compared to the control group. Interestingly, CN not only reduced hydrogen sulfide (H2S) and ammonia (NH3) levels and fecal odor, but also improved feed efficiency in mice. These results demonstrate that oral nano-delivery of anti-ecotoxicological CN is a functional system to deliver curcumin to the gut to improve feed efficiency and reduce fecal odor in mice.
        224.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        A model has been developed to predict natural ventilation in a single zone building with large openings. This study first presents pressure-based equations on natural ventilation, that include the combined effect of wind and thermal buoyancy. Moreover, the concept of neutral pressure level(NPL) is introduced to consider the two-way flow through a large opening. The total pressure differences across the opening and the NPL are calculated, and nonlinear equations are solved to find the zonal pressure to satisfy mass conservation. For this analysis, an iterative technique of successively approximating the zonal pressure is used. The results of applying this study model to several simple cases are as follows. When there is no wind and only the stack effect is caused, a one-way flow occurs in both the top and bottom openings in the case of two openings of equal-area, and a one-way flow occurs in the top opening; however, a two-way flow occurs in the bottom opening in the case of two openings of unequal-area. When there is a wind effect, regardless of whether the outside air temperature is lower or higher than the indoor air temperature, air flows into the room through the bottom opening and out of the room through the top opening. As the wind velocity increases, the wind effect appears to be more influential than the stack effect owing to the temperature difference.
        225.
        2017.12 서비스 종료(열람 제한)
        There are reports that inhaling hypertonic saline with bronchodilator is helpful in the treatment of bronchiolitis. However, further studies are needed to determine if it is helpful to inhale hypertonic saline with bronchodilator in children with recurrent wheezing. We aimed to investigate the effect of hypertonic saline inhalation in children with recurrent wheezing. A total of 40 patients under 6 years of age admitted to Kwangju Christian Hospital from December 2014 to May 2016 were enrolled. Patients were randomly assigned to receive salbutamol. In the control group (n=21), salbutamol (2.5-5 mg / 0.5-1 mL) was inhaled four times a day with physiological saline (0.9% normal saline 1-3 mL). In the experimental group (n=19), the same amount of hypertonic saline (5% saline 1-3 mL) was inhaled four times a day instead of physiological saline. We compared the duration of wheezing remission between patients who had recurrent wheezing (n=40). There was no difference in the duration of wheezing remission in patients who had recurrent wheezing. But the hypertonic saline inhalation group had a lower post treatment clinical score on the 2nd-3rd day of admission than the physiological saline inhalation group. In this study, hypertonic saline inhalation therapy was not significantly effective in the treatment of recurrent wheezing. More additional research is needed to determine whether inhaled hypertonic saline is effective in the treatment of recurrent wheezing.
        226.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to get a more precise frequency of hollow core slabs by comparing the observed values from the actual free vibration tests and the predicted values based on the analysis model. The actual free vibration tests were carried out in the construction field using Ω shaped hollow core slabs. Modal analysis is conducted based on the analysis model that takes into account the differences in section properties due to void parts of slab. The differences between the predicted values based on the modal analysis with analysis model and the measured data from the actual tests range from 2~7%. This study demonstrates that the analysis model that incorporates void parts of slab could be used in evaluating serviceability of hollow core slabs with reasonable accuracies.
        227.
        2017.12 서비스 종료(열람 제한)
        As the number of obese patients increases, childhood obesity also increases and it is recognized as a big problem because it increases the incidence of hypertension, hyperlipidemia, diabetes and metabolic syndrome. Although thyroid hormone abnormalities sometimes exist in obese patients without thyroid disease, there is still much controversy on the impact of obesity on thyroid hormone test results. Accordingly, the present study investigated the correlation between obesity and thyroid hormone concentrations in children with normal thyroid function. In the present study, 356 patients aged 6-18 years who visited the Chosun University Hospital were randomly selected, after exclusion of those with thyroid disease, diabetes mellitus, kidney disease, those with a history of smoking and drinking, and those taking steroids or lipid lowering agents. There were no significant differences in levels of thyroid stimulation hormone (TSH) and free thyroxin (fT4) between males and females. The patients were divided into groups based on serum TSH concentration: group A with TSH < 4.0 μIU/mL and group B with TSH ≥ 4.0 μIU/mL (upper level of normal range). BMI z score, ALT, rGTP, and total cholesterol were significantly higher in group B. Multiple regression analysis adjusted for age, gender, birth weight, and pubertal development showed that TSH and BMI z score were positively correlated, while fT4 was not correlated with other factors.
        228.
        2017.04 서비스 종료(열람 제한)
        A steel tubular member has been generally used for the offshore structure. Its stucutral performance can be decreased due to corrosion damage under severe corrosion environment In this study, to examine the compression performance of steel tubular member depending on corrosion thickness, damaged ratio, FE analyses were conducted and compared.
        229.
        2016.11 KCI 등재 서비스 종료(열람 제한)
        감마나이프 방사선수술은 일회에 고방사선량을 조사하는 치료 전략에 기초하기 때문에 렉셀감마플랜의 결과물에 대한 독립적 인 검증은 환자의 안전성을 보장하고 치료 오류의 위험을 최소화하는데 중요한 절차 중 하나이다. 기존에 개발된 여러 검증 방법들의 구현을 통해 통계적으로 검토하고 치료에 시도했다. 이 연구의 목적은 감마나이프 치료에 대해 제안된 여러 검증방법의 정확도를 적용하고 평가하는 것이었다. 본 연구에서 감마나이프방사선 수술에 의해 치료된 두개 내 병변을 가진 10명의 환자가 포함되었다. 우리는 최대 선량, 임의의 점에서의 선량, 등선량중심점에서의 치료시간에 관하여 제안된 알고리즘과 렉셀감마플랜으로 획득한 데이터를 비교 하 였다. 모든 데이터는 두 개의 상이한 측정 기법을 비교하기 위해 사용되는 통계적 방법인 대응표본 t 검정에 의해 분석되었다. 10가지 사례에서 최대 선량의 통계적 유의성은 제안된 검증방법과 렉셀감마플랜 사이에 관찰되지 않았다. 평균 최대 선량의 차이는 –0.53 Gy에서 3.71 Gy범위내였다. 제안된 검증방법과 렉셀감마플랜에 의해 계산된 임의의 점에서의 선량 또한 통계적으로 유의하지 않았다. 그러나 우리는 등선량중심점에서의 치료시간에 대한 조직최대비율 알고리즘과 렉셀감마플랜사이에 p= 0.021인 통계적인 차이가 발견되었다. 통계적 분석에 의하면 제안된 검증방법은 감마나이프 방사선 수술의 최상의 치료계획을 위해 최대 선량과 임의의 점에서의 선량을 고려할 때 렉셀감마플랜과 상당히 일치한다고 볼 수 있다. 제안된 검증방법들은 과다선량 조사 가능성을 최소화하기 위한 통상적인 정도관리절차의 일부분으로 통합될 수 있다고 여겨진다.
        230.
        2016.10 서비스 종료(열람 제한)
        Based on the study of the Rule of Mixture for FRP (Fiber Reinforced Polymer), it was found that the tensile strength of FRP rebars (reinforcing bars) with circular cross-sections could be estimated with proper reduction coefficients. In this study, a reduction coefficient for FRP rebars with a diameter of 16 mm was proposed.
        231.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        Lactic acid bacteria (LAB) are industrially important microorganisms for probiotics. The recent widespread application of LAB for preparation of functional food is attributable to the accumulating scientific evidence showing their beneficial effects on human health. In this study, we isolated and characterized plant-derived LAB that show angiotensin-converting enzyme (ACE) inhibitory and antioxidant activities. The selected strain K2 was isolated from Kimchi, and identified as Lactobacillus plantarum by 16S rRNA gene analysis. The strain grew under static and shaking culture systems. They were also able to grow in different culture conditions like 25℃∼37℃ temperature, 4∼10 pH range and ∼6% NaCl concentration. L. plantarum K2 was highly resistant to acid stress; survival rate of the strain at pH 2.5 and 3 were 80% and 91.6%, respectively. The strain K2 also showed high bile resistance to 0.3% bile bovine and 0.3% bile extract with more than 74% of survival rate. The cell grown on MRS agar plate containing bile extract formed opaque precipitate zones around the colonies, indicating they have bile salt hydrolase activity. The strain showed an inhibitory activity against pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Listeria monocytogenes; antibacterial activity was probably due to the lactic acid. The K2 strain showed relatively higher autoaggregation values, antihypertensive and antioxidant activities. These results suggest that L. plantarum K2 could be not only applied as a pharmabiotic for human health but also is also starter culture applicable to fermentative products.
        232.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        Concrete structure is a construction material with durability and cost-benefit, however the corrosion in embedded steel causes a critical problem in structural safety. This paper presents an evaluation of chloride resistance and pull-off performance with various corrosion level. For the work, OPC(Ordinary Portland Cement) concrete and GGBFS(Ground Granulated Blast Furnace Slag) concrete are prepared with normal steel. Artificially notch induced FRP Hybrid Bar is also prepared and embedded in OPC concrete and accelerated corrosion test is performed. Through the test, FRP Hybrid Bar with notch is evaluated to have insignificant effect on pull-off capacity when corroded steel shows only 21% level of pull-off capacity. Furthermore GGBFS concrete with normal steel shows over 70% level of pull-off capacity due to reduced corrosion currency.
        233.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        RC(Reinforced Concrete) 부재는 인장영역에서 보강재가 하중을 지지해야 하므로, 철근부식은 내구성 뿐 아니라 안전성에서도 매 우 중요하다. 본 연구에서는 최근 개발된 FRP Hybrid Bar와 일반 철근을 매립한 RC 보부재를 제작하였으며, ICM(Impressed Current Method) 를 적용하여 철근부식을 촉진시켰다. 기존의 이론식인 Faraday 법칙을 이용하여 부식량을 평가하였으며, 일반설계강도를 가진 콘크리트 보부 재에 대하여 휨시험을 수행하였다. 일반 철근에서는 부식량이 4.9∼7.8% 수준으로 평가되었으며 이에 따른 휨 저항능력은 -25.4∼-50.8% 수준 으로 감소하였다. FRP Hybrid Bar를 매립한 RC 보에서는 부식과 휨 저항 감소가 평가되지 않았는데, 이는 에폭시 도료로 코팅된 철근의 우수 한 내부식성에 기인한다. 촉진 부식실험에서는 FRP Hybrid Bar의 우수한 내부식성 및 부착성능을 확인하였는데, 실용화를 위해서는 장기적인 침지를 통한 내구성 평가가 필요하다고 판단된다.
        234.
        2015.10 서비스 종료(열람 제한)
        This paper presents the quantitative evaluation of migration diffusion coefficient considering an effect of cold joint. This also contains an effect of mineral admixture on chloride diffusion coefficient and the interaction of cold joint for chloride diffusion is experimentally investigated. The effect of mineral admixture is very effective to resistance to chloride penetration even if concrete has cold joint section.
        235.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        Nitrogen oxide (NOx) is one of air pollutants generated from the combustion of fuels, causing serious environmental problems. A novel externally oscillated staged combustion for RPF syngas was proposed in this work. The staged combustion could reduce NOx by the fuel-rich state combustion, while the external oscillation could achieve complete burn-out by stabilizing the flame. It also improved combustibility with an acceleration of the mass and heat momentum transfer. Parametric studies were achieved for the NOx reduction characteristics on the air staging and fuel staging in each case of with or without external oscillation. For the case of without oscillation, NOx reduction rate for the fuel staging had higher value as 75% than air staging as 67%. However, an application of external oscillation for both cases gives higher NOx reduction rate of 79%. The optimal condition for the oscillated fuel staging was that the air ratio in main burning zone, reburning zone and burnout zone were 1.1, 0.6 and 1.15, respectively, having 200 Hz of external oscillation.
        236.
        2015.05 서비스 종료(열람 제한)
        연소기에서 연료 연소에 의해서 생성되는 것은 질소산화물의 대부분 NO와 NO2이며, 95%가 NO의 형태로 배출되고 이후 대기 중에 확산되어 공기 중의 산소와 결합하여 NO2가 된다. 질소산화물은 광화학 스모그의 원인으로 인체에 해를 끼칠 뿐 아니라 산성비의 원인이 되는 등 환경에 대한 심각한 문제를 야기하고 있기 때문에 실용 연소기에 대한 규제가 한층 강화되어 질소산화물 발생을 억제해야 하는 필요성이 점차 증대되고 있다. 최근에는 에너지 문제에 의해 폐기물 가스화에 의해 생성된 가스를 활용이 점차 증가하고 있으므로, 이에 대한 질소산화물의 저감 연구가 필요하다. 본 연구에서는 RPF 가스화 가스를 모사하여 연소시 발생되는 질소산화물을 저감시키기 위해 다단 연소와 음향가진 기술을 적용하였다. 이 때, 발생되는 질소산화물의 저감 특성을 파악하기 위하여 공기 다단 연소, 연료 다단 연소 그리고 외부가진을 주사하여 공기비 및 주파수 변화에 따른 변수별 연구를 수행하였다. Fig. 1은 공기 다단 연소를 적용하여 총공기비 변화에 따른 결과이다. 각각의 총공기비에 따른 주연소 영역의 공기비가 감소함에 따라 질소산화물 감소되는 경향을 보이며, 주연소총공기비 0.7에서 가장 낮은 값을 나타내었다. Fig. 2는 기존 조건에서 공기 다단 연소 및 외부가진을 적용하였을 때, 질소산화물과 중간생성물인 암모니아와 시안화수소를 나타낸 결과이다. 주연소 영역 공기비 0.7, 완전연소 영역 공기비 1.1, 체류시간 1.265 s 일 때 질소산화물 421 ppm으로 다단 연소 미적용한 경우에 비해 67% 저감되었다. 외부가진 적용시 400 Hz에서 273 ppm으로 다단 연소 및 외부가진 미적용하였을 때에 비해 79% 저감되었다.
        237.
        2014.12 서비스 종료(열람 제한)
        We experienced an 18-month-old patient with congenital lobar emphysema who underwent one-lung ventilation. With con-sideration that positive pressure ventilation could induce cardiopulmonary distress, induction was performed with spontane-ous breathing using sevoflurane without neuromuscular blocking agent. Bronchospasm occurred after intubation and posi-tion change, twice. He was relieved by administration of neuromuscular blocking agents. We discussed induction methods with minimal positive-pressure ventilation and the treatments for bronchospasm.
        238.
        2014.10 서비스 종료(열람 제한)
        In this study, it was evaluated the permeability of cold joint concrete, to evaluated the permeability considering slag concrete and OPC. In addition, the water permeability was evaluated by comparing the sound and cold joint concrete. As a result, OPC-Joint(3.76×10-10m/s), Slag-Joint(3.36×10-10m/s), OPC(2.65×10-10m/s), Slag(2.36×10-10m/s) was evaluated in this order. The OPC-joint is the most highly evaluated. This is estimated to be because the density of the pore structure.
        239.
        2013.11 KCI 등재 서비스 종료(열람 제한)
        균열을 가진 콘크리트에서는 균열폭으로 유입되는 염화물 이온에 의해 열화가 가속화된다. 본 연구는 균열을 가진 콘크리트의 염화물 확산에 대한 모델링으로, 정상상태를 가정하여 1차원 (이방성) 및 2차원 (등방성) 균열 모델링을 수행하였다. 기존의 균열 모델링에서는 직사각형 균열패턴으로 모델링을 수행하였으나, 본 연구에서는 조도를 가진 쐐기형 형태로 균열을 모델링하였다. 검증을 위하여 1차원 유입에 대해서는 콘크리트 시편에 균열을 유입하여 염화물 영동실험을 수행하였으며, 2차원 유입에 대해서는 기존의 실험결과를 이용하여 검증을 수행하였다. 모든 경우에서 균열형태를 쐐기형으로 고려하여 염화물 확산성이 감소되었으며, 조도를 고려함으로서 합리적인 결과가 도출되었다. 특히 0.10~0.15의 조도계수를 고려할 때, 실험값에 가장 근접한 결과를 나타내었다.
        240.
        2013.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The indigenous Saccharomyces cerevisiae strains S13 and D8 were isolated at the microbial succession stage during spontaneous fermentation of Campbell Early wine as a resistant to potassium metabisulfite and a high sugar concentration. In this study, the fermentation characteristics of Campbell Early wine were investigated and compared with those of S. cerevisiae W-3, an industrial wine yeast. Alcohol production by the two strains was delayed at the initial fermentation stage, but increased fast when the fermentation continued. After the fermentation, the S13 and D8 wines contained 12.6% and 13.2% (v/v) alcohol, respectively, which were significantly higher than the alcohol content of the W-3 wine (12%, v/v). No marked differences were observed in the residual soluble solid content and the pH. However, the S13 and D8 wines showed high levels of total acid content, including malic and lactic acids. Especially, the lactic acid content was 8.9-fold in the S13 wine and six-fold in the D8 wine, compared with that of the W-3 wine. The two strains produced a higher level of acetaldehyde and a lower amount of methanol in the wine than the W-3 strain. The iso-Butanol content was lower in the two indigenous yeast wines with similar levels of n-propanol and iso-amyl alcohol contents than that in the W-3 wine. In the sensory evaluation, the S13 and D8 wines had higher scores for their color, flavor, taste and overall preferences than the W-3 wine. Especially, the S13 and D8 wines had much higher scores than the W-3 wine for flavor and color, respectively.