• 한국항공우주학회지
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• 제46권1호
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• pp.1-9
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• 2018

람다 날개 형태의 무인전투기는 동체-날개 융합익의 형태를 띄고 있어 일반적인 항공기에 비해 상대적으로 항력이 작고 레이더 반사 면적이 작아 우수한 스텔스 성능을 갖는다. 그러나 앞전 후퇴각에 의해 생성되는 앞전 와류의 영향으로 특정 받음각에서 피칭모멘트가 급격히 증가하는 현상이 나타난다. 본 연구에서는 무미익 람다 날개 형상을 기반으로 한 UCAV 1303 모델을 사용하여 풍동시험과 전산해석을 수행하였다. 실험 풍속은 50 m/s, 받음각 범위는 $-4^{\circ}{\sim}28^{\circ}$ 으로 하였으며 전산해석 또한 실험 조건과 동일하게 연구를 수행하였다. 본 연구를 통해 UCAV의 날개 비틀림이 피칭모멘트의 안정성에 미치는 영향을 확인하였다. 그 결과 날개에 음의 비틀림 각을 적용하였을 때 날개 바깥쪽에서의 유동 박리가 지연되면서 Pitch-break가 발생하는 받음각이 증가하였고, 양의 비틀림 각을 적용하였을 때 Pitch-break가 발생하는 받음각이 감소하였지만 양항비가 증가하는 것을 확인하였다.

• Journal of Trauma and Injury
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• 제24권2호
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• pp.68-74
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• 2011

Purpose: Although pancreas injury is rare in abdominal trauma, it poses a challenge to the surgeon because its clinical features are not prominent and the presence of main duct injury cannot be easily identified by imaging studies. Furthermore, severe pancreas injuries require a distal pancreatectomy or a pancreaticoduodnectomy which are associated considerable morbidity and mortality. We reviewed the clinical features of and outcomes for patients with pancreas injury. Methods: For 10 years from Jan. 2001 to Dec. 2010, thirty-four patients were diagnosed as having pancreas injury by using an explo-laparotomy. Patients successfully treated by non-operative management were excluded. Patients were divided into early (n=18) and delayed surgery groups (n=11) based on an interval of 24hours between injury and surgery. The clinical features of and the outcomes for the patients in both groups were compared. Results: Males were more commonly injured (82.4% vs.17.6%). The mean age was 37.2 years. The injury mechanisms included vehicle accidents (62.9%, 22/34), assaults (20%, 7/34), and falls (11.4%, 3/34). The head and neck of the pancreas was most commonly injured, followed by the body and the tail (16, 12, and 6 cases).Of the 34 patients, 26 (76.5%) patients had accompanying injuries. Grade 1 and 2 occurred in 14 (5 and 9) patients, and grade 3, 4, and 5 occurred in 20 (16, 3, and 1) patients. The early and delayed surgery groups showed no difference in surgical outcomes. Two patients with grade 3 in the early surgery group died after surgery,one due to massive hemorrhage and the other due to septic shock. Of the five patients initially managed non-operatively, three developed peripancreatic necrosis and two developed pseudocyst. All five patients were successfully cured by surgery. Conclusion: All cases of pancreas injury in this study involved blunt injury, and accompanying injury to major vessels or the bowel was the major cause of mortality. Surgery delayed for longer than 24 hours after was not associated with adverse outcomes.

• Journal of Chest Surgery
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• 제31권3호
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• pp.291-297
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• 1998

예전에는 그리 흔하지 않았던 흉골 골절이 자동차 사고의 증가와 비례해서 그 빈도가 증가 추세에 있다. 흉골 골절을 유발할 정도의 과도한 충격이나 골절로 인한 골편부는 그 위치가 종격동이나 흉강안의 기관들 근처에서 발생하기 때문에 이러한 기관이 흉골 골절로 손상을 받지 않았는지 잘 평가하는 것은 치료하는 데 있어 매우 중요하다. 본 연구는 1993년 3월부터 1997년 2월까지 4년간 서울 위생병원 흉부외과에서 치료한 72명의 흉골 골절 환자를 대상으로 이루어졌다. 흉부 손상 중 흉골 골절의 빈도는 12.2%였고 환자의 평균연령은 43.2세였다. 자동차 사고(84%)와 흉골 체부 골절(95.8%)이 가장 흔한 골절 요인과 위치였고 골절 형태는 골단부 이탈(displacement)이나 교차(overriding)없이 골절만인 경우가 51명(70.8%)으로 가장 많았고 골단부의 이탈은 전방(anterior, 19.4%)이 후방(posterior, 5.6%)보\ulcorner 많았다. 흉부 좌상 환자(LDH:13%, CPK:14%, CK-MB:12.2%, CK-MB>6% of CPK:5.3%)보다 흉골 골절 환자(LDH:56.8%, CPK:66.6%, CK-MB:43.1%, CK-MB>6% of CPK:25.4%)와 흉골 골단부 이탈로 수술 받아야 했던 환자(LDH:76%, CPK:95%, CK-MB:38%, CK-MB>65% of CPK:33%)에서 심동위효소 증가의 빈도는 컸고, 심동위효소의 평균 수치도 높았다. 그러나 증가된 심동위효소의 수치가 정상화되는데 소요되는 시간은 흉부 좌상 환자와 흉골 골절 환자 사이에 별 차이가 없었다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.31-31
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• 2003

The incidence of reproductive abnormalities in the male has been reported to have increased during the past 50 years. These changes may be attributable to the presence of chemical with oestrogenic activity in our environment. Present study was carried out to determine the effects of maternal exposure to xenoestrogens on the testicular development and on the transcriptional expression of the steroidogenic enzyme and subunits of inhibin/activin in testis of male offspring. Pregnant female mice were administrated with 4-tert-octylphenol (OP; 2, 20, 200mg/kg), Bisphenol A (BPA; 2, 20, 200$\mu\textrm{g}$/kg), $\beta$-estradiol 17-valerate (EV; 2$\mu\textrm{g}$/kg) or vehicle (CV; corn oil) during gestational days 11 to 17. Offsprings were sacrificed on gestational day 18 (fetal 18) and neonatal day 7. Body weights were significantly increased in groups treated with all doses of OP and BPA. Maximum seminiferous tubules diameter on gestational day 18 were not changed in any treatment group, however, they were significantly increased on the neonatal day 7 in the group treated with low-dose of OP (2 mg/kg) and BPA (2 $\mu\textrm{g}$/kg). Increased expression of the P450$_{17a}$-hydroxylase dehydrogenase (P450$_{17a}$), 3$\beta$-hydroxylase dehydrogenase (3$\beta$-HSD), and 17$\beta$-hydroxylase dehydrogenase (17$\beta$-HSD) on gestational day 18 were observed in the groups treated with 2 or 20 mg/kg of OP. However, expression of the steroidogenic enzymes were not changed in the groups treated with all the doses of BPA. In contrast with the results from fetal testis, no expressional changes of these enzymes was found in all the OP-treated group and increased expression of inhibin/activin $\beta$B subunit mRNA were obseued in the 200 $\mu\textrm{g}$/kg BPA-treated group in the neonatal day 7. These results suggest that gestational exposure to low level of xenoestrogen causes a stimulatory effects on the transcriptional expressions of steroidogenic enzymes and subunits of inhibin/activin and on the seminiferous tubule development by their estrogen-like actions.ons.

• Asian-Australasian Journal of Animal Sciences
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• 제28권11호
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• pp.1558-1564
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• 2015

Cutaneous evaporative heat loss in Bos indicus and Bos taurus has been well documented. Nonetheless, how crossbreds with different fractional genetic proportions respond to such circumstances is of interest. A study to examine the physiological responses to cutaneous evaporative heat loss, also lactation period and milk yield, were conducted in Sahiwal (Bos indicus, n = 10, $444{\pm}64.8kg$, $9{\pm}2.9years$), Holstein Friesian (Bos taurus, HF100% (n = 10, $488{\pm}97.9kg$, $6{\pm}2.8years$)) and the following crossbreds: HF50% (n = 10, $355{\pm}40.7kg$, $2{\pm}0years$) and HF87.5% (n = 10, $489{\pm}76.8kg$, $7{\pm}1.8years$). They were allocated so as to determine the physiological responses of sweating rate (SR), respiration rate (RR), rectal temperature (RT), and skin temperature (ST) with and without hair from 06:00 h am to 15:00 h pm. And milk yield during 180 days were collected at days from 30 to 180. The ambient temperature-humidity-index (THI) increased from less than 80 in the early morning to more than 90 in the late afternoon. The interaction of THI and breed were highly affected on SR, RR, RT, and ST (p<0.01). The SR was highest in Sahiwal ($595g/m^2/h$) compared to HF100% ($227g/m^2/h$), and their crossbreds both HF50% ($335g/m^2/h$) and HF87.5% ($299g/m^2/h$). On the other hand, RR was higher in HF87.5% (54 bpm) and both HF100% (48 bpm) and HF50% (42 bpm) than Sahiwal (25 bpm) (p<0.01). The RT showed no significant differences as a result of breed (p>0.05) but did change over time. The ST with and without hair were similar, and was higher in HF100% ($37.4^{\circ}C$; $38.0^{\circ}C$) and their crossbred HF50% ($35.5^{\circ}C$; $35.5^{\circ}C$) and HF87.5% ($37.1^{\circ}C$; $37.9^{\circ}C$) than Sahiwal ($34.8^{\circ}C$; $34.8^{\circ}C$) (p<0.01). Moreover, the early lactation were higher at HF100% (25 kg) and 87.5% (25 kg) than HF50% (23 kg) which were higher than Sahiwal (18 kg) while the peak period of lactation was higher at HF100% (35 kg) than crossbreds both HF87.5% and HF50% (32 kg) which was higher than Sahiwal (26 kg) (p<0.05). In conclusion, sweating and respiration were the main vehicle for dissipating excess body heat for Sahiwal, HF and crossbreds, respectively. The THI at 76 to 80 were the critical points where the physiological responses to elevated temperature displayed change.

• Nutrition Research and Practice
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• 제9권2호
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• pp.129-136
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• 2015

BACKGROUND/OBJECTIVES: A variety of immunomodulators can improve the efficacy of low-dose chemotherapeutics. Active hexose correlated compound (AHCC), a mushroom mycelia extract, has been shown to be a strong immunomodulator. Whether AHCC could enhance the antitumor effect of low-dose 5-fluorouracil (5-FU) via regulation of host immunity is unknown. MATERIALS/METHODS: In the current study Hepatoma 22 (H22) tumor-bearing mice were treated with PBS, 5-FU ($10mg{\cdot}kg^{-1}{\cdot}d^{-1}$, i.p), or AHCC ($360mg{\cdot}kg^{-1}{\cdot}d^{-1}$, i.g) plus 5-FU, respectively, for 5 d. $CD^{3+}$, $CD^{4+}$, $CD^{8+}$, and NK in peripheral blood were detected by flow cytometry. ALT, AST, BUN, and Cr levels were measured by biochemical assay. IL-2 and $TNF{\alpha}$ in serum were measured using the RIA kit and apoptosis of tumor was detected by TUNEL staining. Bax, Bcl-2, and TS protein levels were measured by immunohistochemical staining and mRNA level was evaluated by RT-PCR. RESULTS: Diet consumption and body weight showed that AHCC had no apparent toxicity. AHCC could reverse liver injury and myelosuppression induced by 5-FU (P < 0.05). Compared to mice treated with 5-FU, mice treated with AHCC plus 5-FU had higher thymus index, percentages of $CD^{3+}$, $CD^{4+}$, and NK cells (P < 0.01), and ratio of $CD^{4+}$/$CD^{8+}$ (P < 0.01) in peripheral blood. Radioimmunoassay showed that mice treated with AHCC plus 5-FU had the highest serum levels of IL-2 and $TNF{\alpha}$ compared with the vehicle group and 5-FU group. More importantly, the combination of AHCC and 5-FU produced a more potent antitumor effect (P < 0.05) and caused more severe apoptosis in tumor tissue (P < 0.05) compared with the 5-FU group. In addition, the combination of AHCC and 5-FU further up-regulated the expression of Bcl-2 associated X protein (Bax) (P < 0.01), while it down-regulated the expression of B cell lymphoma 2 (Bcl-2) (P < 0.01). CONCLUSIONS: These results support the claim that AHCC might be beneficial for cancer patients receiving chemotherapy.

• Journal of Korean Neurosurgical Society
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• 제29권1호
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• pp.58-65
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• 2000

Objective : Thoracolumbar junction is second most common level of injury next to cervical spine. The object of this study is to study the usefulness of surgical titanium mesh instead of bone graft, as well as to evaluate the correction of spinal deformity and safety of early ambulation in patients with injury at thoracolumbar junction. Patients and Methods : This review included 51 patients who were operated from July 1994 to December 1997. The injured spine is considered to be unstable, if it shows involvement of two or more columns, translatory displacement more than 3.5mm, decrease more than 35% in height of vertebral body and progression of malalignment in serial X-ray. The decision to operate was determined by (1) compression of spinal cord or cauda eguina, (2) unstable fracture, (3) malalignment and (4) fracture dislocation. The procedure consisted of anterior decompression through corpectomy and internal fixation with anterior instrument and surgical titanium mesh which was impacted with gathered bone chip from corpectomy. Results : Fifty-one patients were followed up for at least 12 months. The main causes of injury were fall and vehicle accident. The twelfth thoracic and the first and the second lumbar vertebrae were frequently involved. Complete neural decompression was possible under direct vision in all cases. Kyphotic angulation occurred in a patient. Radiologic evaluation showed correction of deformity and no distortion or loosening of surgical titanium mesh with satisfactory fixation postoperatively. Conclusions : We could obtain neurological improvement, relief of pain, immediate stabilization and early return to normal activities postoperatively. Based on these results, authors recommend anterior decompression and internal fixation with surgical titanium mesh in thoracolumbar unstable spine injuries.

• 한국철도학회논문집
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• 제15권1호
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• pp.48-61
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• 2012

열차 진동 저감을 위한 플로팅 슬래브궤도의 설계에 있어서 주행 안전, 승차감 및 사용성을 확보하는 것이 매우 중요하다. 본 연구에서는 플로팅 슬래브궤도에서 열차 주행안전과 승차감, 사용성 확보를 위한 요구조건을 분석하여 제시하였고, 열차-궤도 상호작용을 고려한 동적 해석기법을 적용하여 시스템 고유진동수, 스프링 지지간격 및 배치방법, 감쇠비 등 주요 시스템 설계변수에 따라 일반 콘크리트궤도와의 접속구간을 포함한 플로팅 슬래브궤도 구간에서의 열차 및 궤도의 동적 거동을 분석하였다. 연구결과에 따르면 일반 궤도와 플로팅슬래브궤도 간의 접속구간에서의 지지강성의 차이에 의해 윤중 변동율, 레일 응력, 레일 인상력 등의 동적 응답이 크게 증가하는 것으로 나타났으며, 따라서 접속구간에서 스프링 지지간격을 좁히거나 스프링 강성의 차이를 완화시키는 방안이 주행안전과 궤도 사용성 확보를 위해 효과적인 것으로 나타났다. 한편 차체 가속도로 평가하는 승차감은 접속구간에서의 지지강성의 차이에 의해서는 거의 영향을 받지 않고, 시스템 튜닝 주파수에 의해 가장 큰 영향을 받는 것으로 나타났으며, 승차감 확보를 위해서는 적절한 시스템 튜닝 주파수를 선정하는 것이 매우 중요한 것으로 나타났다. 이 밖에 감쇠비, 스프링 간격, 열차속도에 따른 영향을 분석하였다.

• 한국잠사곤충학회지
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• 제17권2호
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• pp.133-139
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• 1975

경구투여용 누에 병치료약을 개발하고 이를 임상적으로 적용하려면 필연적으로 이러한 치료약물에 대한 부형제를 생각하지 않을 수 없다. 본인은 이러한 효용의 부형제로서 유당, 카페인 및 요소를 추정하고서 이들 세가지 약제의 경구투여용 누에병치료약의 부형제로서의 응용가능성을 알아보기 위한 기초적 실험을 1974년 춘잠기, 1975년 춘잠기 및 1975년 추잠기의 세차례에 걸쳐 서울대학교 농과대학 잠실에서 실시했다. 1974년 춘잠기에는 4령기 5령기에 걸쳐, 1975년 춘잠기와 추잠기에는 각기 5령기 동안에 유당 카세인 및 요소를 투여량과 투여회수를 달리하면서 누에유충에 투여하여 이들 세가지 약제의 누에유충발육에 미치는 영향과 고치만들기에 미치는 영향을 관찰했다. 유당은 실험관찰 한 모든 조건에 있어서 누에유충발육과 고치만들기에 사실상 아무런 영향도 미치지 않았다. 카세인은 이틀 걸러 한번씩 투여하는 경우는 대체로 무난했으나 모든 투여조건에 있어서 비정상고치의 발생이 비교적 많았다. 그리고 요소는 대체로 모든 투여조건에 있어서 누에유충의 발육을 억제했다. 유당, 카세인 및 요소의 누에유충발육과 고치만들기에 미치는 영향은 누에의 암수별과는 아무런 관계도 없는 것으로 보였다. 이들 세가지 약제의 실험적 누에병 치료에 있어서의 부형제적 효과와 견사품질에 미치는 영향에 관해서는 앞으로 계속해서 검토해 보는 것이 바람직해 보인다.

• 대한본초학회지
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• 제30권4호
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• pp.37-44
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• 2015

Objectives : The present study was designed to evaluate the anti-inflammatory and anti-oxidative stress activities through regulation of Nrf2-mediated genes by Rhei rhizoma and Glycyrrhiza rhizoma combined extract (RGE) in reflux esophagitis.Methods : The antioxidant activity of RGE in vitro was measured in terms of radical scavenging capacity such as DPPH and ABTS. RGE was administered at 350 mg/kg body weight prior to induction of reflux esophagitis. Reflux esophagitis was induced that tied the pylorus and the transitional junction between the forestomach and the corpus in Sprague-Dawley rats.Results : RGE scavenged DPPH and ABTS effectively and IC₅₀of RGE each were 4.9 μg/ml and 45.6 μg/ml. Our results show that RGE administration markedly ameliorated mucosal damage upon histological evaluation. In serum and esophagus tissue, RGE significantly suppressed the oxidative stress biomarkers. Reflux esophagitis induced rats exhibited down-regulation of antioxidant-related proteins in the esophagus; however, the levels with treatment of RGE were significantly higher than those of vehicle reflux esophagitis rats. RGE treatment caused significant reductions in activation of NF-κB transcription factor. Thus, RGE significantly exhibited potent anti-inflammatory activities by suppressing the protein expression levels of pro-inflammatory proteins such as COX-2 and iNOS and inflammatory cytokines such as TNF-αin the esophagus tissue.Conclusions : Reflux esophagitis caused considerable levels of oxidative stress in the esophageal mucosa and the administration of RGE reduced the esophageal mucosa damage through the regulation of Nrf2 and NF-κB pathways. Our findings can considered as supplementary therapy in the prevention or treatment of reflux esophagitis.