• 과학기술학연구
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• 제20권1호
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• pp.1-38
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• 2020

1963년 「공해방지법」의 제정 이래 악취는 정부가 규제하고 관리해야 할 문제로 인식되었다. 다만 규제 대상으로서의 악취는 공장의 생산과정에서 배출되는 악취로 한정되었고, 생활 쓰레기나 하천의 오염으로부터 발생하는 생활악취는 오랫동안 규제 영역 바깥에 놓여 있었다. 본 논문은 환경 규제와 관련해 신체적 감각의 역할에 주목하는 과학 기술학의 논의를 따라 생활악취가 규제대상으로 포함되는 과정을 추적한다. 이를 위해 본 연구는 올림픽을 앞두고 발생한 악취 문제에 주목함으로써 악취가 부끄럽고 수치스러운 대상으로 여겨지게 되었으며, 악취 문제의 대응 과정에서 생활악취가 법적 규제의 대상으로 포함되었음을 보일 것이다.

• 전력전자학회논문지
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• 제11권4호
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• pp.385-394
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• 2006

일반적인 푸시풀 컨버터는 스위치 소자의 전압 스트레스로 인하여 그 사용범위가 제한적이다. 그러나 푸시풀 컨버터는 연료전지와 같이 가변의 저전압에서 고전압 출력을 요하는 전력변환기에 적합한 구조이다. 본 논문에서는 연료전지 시스템에 ZVS-ZCS가 가능한 새로운 전력변환기 구조를 제안한다. 제안된 푸시폴 컨버터의 스위치 소자는 새로운 수동 클램프 회로에 의해 ZVS 또는 ZCS가 이루어진다. 또한 이러한 수동 클램프 회로로 푸시풀 컨버터의 순시과전압 문제가 해결되었다. 또한 두 배의 주파수를 갖는 벅 컨버터의 스위칭 신호가 푸시풀 컨버터의 스위칭 신호에 동기 시킴으로서 전류 형 인덕터와 변압기 권선의 피크 전류가 저감된다. 제안하는 계통 연계형 연료 전지 시스템에 대한 동작을 이론적으로 분석하고 시뮬레이션 및 DSP TMS320F2812 을 이용한 1 [kW]급 시작품의 실험 결과로부터 제안하는 인버터의 타당성을 검증하였다.

• 응용통계연구
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• 제28권5호
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• pp.847-858
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• 2015

남극해에서는 우리나라를 포함한 연안 강대국들의 원양어업이 활발히 성행하고 있다. 주인 없는 남극해의 생태계를 보호하기 위해 조업 국가들은 남극해양생물자원보존위원회를 만들고 협약을 맺어 일정한 어획량만 조업하고 금지기간과 금지구역을 설정하여 불법조업을 방지하고 있다. 남극해에서 조업하는 어종 중의 하나가 이빨고기(tooth fish)인데 비싼 값 때문에 불법조업이 있는 경우가 많다. 한 배의 조업성과는 CPUE(catch per unit effort)로 나타낼 수 있고, 한 지역에서 조업한 배들의 CPUE는 단일 또는 혼합 극단분포 형태를 가진다. 단일 극단분포일 경우 이상점 탐색은 상위 백분위수를 이용하면 된다. 본 논문은 자료가 혼합 극단분포인 경우 이상점 탐색을 위한 통계적 방법을 연구하고자 한다. 본 연구에서는 자료에 적합한 혼합 극단분포 모형을 EM 알고리즘으로 추정한 후 로그 가능도함수 값을 이용하거나 사후 확률을 이용한 이상점 탐색 알고리즘을 제안한다. 이 방법을 남극해 조업 데이터에 적용하여 시뮬레이션 한 결과 통계적 방법 적용의 가능성을 보여주었다.

• Archives of Plastic Surgery
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• 제38권4호
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• pp.391-397
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• 2011

Purpose: The injection of various materials, including medical fillers and unregulated products, is widespread, potentially causing the development of foreign body granulomas. Should this occur on the nose, the contour deformity and inflammatory signs that result from these granulomas are aesthetically undesirable to patients. The purpose of our study is to share our experiences using different surgical approaches, depending on the affected portion of the nose, to optimize management of this challenging problem and to evaluate patient's satisfaction using our in-house questionnaire along with degree of improvement by two independent plastic surgeons. Methods: We treated 18 patients who underwent surgical excision of nasal foreign body granulomas via a perilesional approach to the lesion (n=12) or by transcolumellar incision (n=6) at our hospital over a period of seven years from March 2003 to October 2010. Nonparametric statistics were used and are presented as medians (25th-75th). Patient satisfaction was evaluated on a scale of 1 to 5 using an in-house questionnaire. All pre-and post-operative photographs were analyzed by two independent plastic surgeons. Post-operative outcomes were evaluated based on the surgeons' consensus ratings. Results: All patients receiving the transcolumellar approach reported a high level of satisfaction with the results. All but two patients who received the perilesional approach were satisfied with the outcome. No outcomes were rated as no change or worse by the consensus ratings. Conclusion: For the upper two-thirds of the nose, perilesional surgical excision can lead to substantial patient satisfaction with modified contour deformity and infection control. The transcolumellar approach resulted in better outcomes and patient satisfaction for the lower one-third of the nose.

• Parasites, Hosts and Diseases
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• 제58권2호
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• pp.121-127
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• 2020

Pakistan is at intersection of hyperendemic regions for hydatidosis. Current study aimed to determine the prevalence of hydatid cysts and cyst characteristics in different intermediate hosts (sheep, goats, cattle and buffaloes) across the 4 provinces of Pakistan. A total of 991 sheep, 1,478 goats, 1,602 cattle and 1,343 buffaloes were examined for presence of hydatid cysts during 2 years (January 2016-December 2018). Differences in frequency of hydatidosis were observed with highest overall prevalence in buffaloes (11.9%) and sheep (11.5%). Highest prevalence and burden of infection were observed in older age animals (23.8%, 9.78±0.49) and females (26.5%, 12.53±0.67). Data for seasonal prevalence alluded to year-round presence of disease with non-significant statistical difference. Organ predilection indicated liver as the most preferred site of cyst localization followed mainly by lungs. An over-dispersion pattern was observed in all infected animals as majority of cysts belonged <10 cysts per infected host category. Highest percentage of fertile cysts was observed in liver of sheep. Interestingly, solitary form of cysts had higher fertility rate than multiple form. Amid lack of data and wide gap of knowledge, this study would try to fill up the lacunae regarding this neglected tropical disease. Extensive rearing of livestock, unregulated official slaughter and home slaughtering have played role in adaptability of E. granulosus in Pakistan.

• Childhood Kidney Diseases
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• 제20권1호
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• pp.11-17
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• 2016

Appropriate control of diet and water intake is important for maintaining normal blood pressure, fluid and electrolyte homeostasis in the body. It is relatively understood that the amount of sodium and potassium intake directly affects blood pressure and regulates ion transporters; Na and K channel functions in the kidney. However, little is known about whether diet and water intake regulates Aquaporin (AQP) function. AQPs, a family of aquaporin proteins with different types being expressed in different tissues, are important for water absorption by the cell. Water reabsorption is a passive process driven by osmotic gradient and water permeability is critical for this process. In most of the nephron, however, water reabsorption is unregulated and coupled to solute reabsorption, such as AQP1 mediated water absorption in the proximal tubule. AQP2 is the only water channel founded so far that can be regulated by hormones in the kidney. AQP2 expressed in the apical membrane of the principal cells in the collecting tubule can be regulated by vasopressin (antidiuretic hormone) controlling the final volume of urine excretion. When vasopressin binds to its receptor on the collecting duct cells, it stimulates the translocation of AQP2 to the membrane, leading to increased water absorption via this AQP2 water channel. However, some studies also indicated that the AQP2 is also been regulated by vasopressin independent mechanism. This review is focused on the regulation of AQP2 by diet and the amount of water intake on salt and water homeostasis.

• Nutritional Sciences
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• 제9권4호
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• pp.295-300
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• 2006

Iron bound to heme appears to be more bioavailable than iron salts. A clinical study was performed to investigate the absorption efficiency of heme-iron and iron-salt products available. Heme-iron and nonheme-iron supplements have become available in Korea. We performed iron absorption studies to compare the absorption of heme-iron polypeptide (HIP) products made from digested hemoglobin, produced in Korea (HIPk) and imported from Japan (HIj), with that of iron salts. In the study, 80 subjects were divided into 5 groups (n=56): placebo group; 12 mg glucose, HIPk group; 12 mg iron as HIPk, HIj group; 12 mg iron as HIj, iron-salt group 1; 12 mg of iron as ferrous aminoacetate, and iron-salt group 2; 100 mg iron as ferrous aminoacetate. Changes in serum iron levels were measured at 3 and 5 hours post ingestion. Absorption of iron in HIPk was higher compared to HIj, iron-salt or placebo. There was a significant inverse correlation between low serum iron levels $(<80{\mu}g/dl)$ and iron absorption from HIPk. These results demonstrated that HIPk was more bioavailable, even taken with a meal, and would have potential advantages over iron salt or HIj as an iron supplement. Our results indicate that heme-iron absorption is regulated by iron status through a heme receptor, whereas iron-salt absorption is unregulated.

• Nutrition Research and Practice
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• 제15권5호
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• pp.591-603
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• 2021

BACKGROUND/OBJECTIVES: Unregulated inflammatory responses caused by hyperglycemia may induce diabetes complications. Hesperetin, a bioflavonoid, is a glycoside in citrus fruits and is known to have antioxidant and anticarcinogenic properties. However, the effect of inflammation on the diabetic environment has not been reported to date. In this study, we investigated the effect of hesperetin on proinflammatory cytokine secretion and its underlying mechanistic regulation in THP-1 macrophages with co-treatment LPS and hyperglycemic conditions. MATERIALS/METHODS: THP-1 cells differentiated by PMA (1 µM) were cultured for 48 h in the presence or absence of hesperetin under normoglycemic (5.5 mM/L glucose) or hyperglycemic (25 mM/L glucose) conditions and then treated with LPS (100 ng/mL) for 6 h before harvesting. Inflammation-related proteins and mRNA levels were evaluated by enzyme-linked immunosorbent assay, western blot, and quantitative polymerase chain reaction analyses. RESULTS: Hesperetin (0-100 µM, 48 h) treatment did not affect cell viability. The tumor necrosis factor-α and interleukin-6 levels increased in cells co-treated with LPS under hyperglycemic conditions compared to normoglycemic conditions, and these increases were decreased by hesperetin treatment. The TLR2/4 and MyD88 activity levels increased in cells co-treated with LPS under hyperglycemic conditions compared to normoglycemic conditions; however, hesperetin treatment inhibited the TLR2/4 and MyD88 activity increases. In addition, nuclear factor-κB (NF-κB) and Acetyl-NF-κB levels increased in response to treatment with LPS under hyperglycemic conditions compared to normoglycemic conditions, but those levels were decreased when treated with hesperetin. SIRT3 and SIRT6 expressions were increased by hesperetin treatment. CONCLUSIONS: Our results suggest that hesperetin may be a potential agent for suppressing inflammation in diabetes.

• Tribology and Lubricants
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• 제34권6호
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• pp.292-299
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• 2018

The objective of this research is to investigate the impact of engine oil aging on PM(Particulate Matter), exhaust gases, and DPF. It is widely known that the specification of a lubricant and its consumption in an ICE considerably influences the release of regulated harmful emissions under normal engine operating conditions. Considering DPF clogging phenomena associated with lubricant-derived soot/ash components, a simulated aging mode is designed for DPF to facilitate engine dynamometer testing. A PM/ash accumulation cycle is developed by considering real-world engine operating conditions for the increment of engine oil consumption and natural DPF regeneration for ash accumulation. The test duration for DPF aging is approximately 300 h with high- and low-SAPs engine oils. Detailed engine lubricant properties of new and aged oils are analyzed to evaluate the effect of engine oil degradation on vehicle mileage. Furthermore, physical and chemical analyses are performed using X-CT, ICP, and TGA/DSC to quantify the engine oil contribution on the PM composition. This is achieved by sampling with various filters using specially designed PM sampling equipment. Using high SAPs engine oil causes more PM/ash accumulation compared with low SAPs engine oils and this could accelerate fouling of the EGR in the engine, which results in an increase in harmful exhaust gas emissions. These test results on engine lubricants under operating conditions will assist in the establishment of regulated and unregulated toxic emissions policies and lubricant quality standards.

• 한국분무공학회지
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• 제23권4호
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• pp.175-184
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• 2018

Emission characteristics of regulated (NOx, PM, CO, NMHC) and unregulated (VOCs, aldehydes, PAHs) air pollutants were investigated for diesel heavy duty buses equipped with different after-treatment systems (DPF+EGR and SCR) under urban driving cycle. The combustion temperature and the working temperature of SCR catalysts were important to make impact on NOx emissions, whereas PM emissions were low. The alkane groups dominated NMVOCs emissions, making 42.6~59.4% of sum of the NMVOCs emissions. Especially, alkane emissions of DPF+EGR-equipped vehicle included DOC had 14.9~15.5% higher than those of SCR-equipped vehicle due to low efficiency of oxidation catalyst. In the case of individual NMVOCs, n-nonane and propylene emissions highly occupied for DPF+EGR and SCR, respectively. Formaldehyde emissions among aldehydes were the highest and PAHs emissions were hardly detected except naphthalene and phenanthrene. The NMHC speciation has been shown to be the highest of the formaldehyde ranged 20.8~21.5%. The results of this study will be contributed to establish Korean HAPs emission inventory for automobile source.