• 한국항공우주학회지
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• 제33권8호
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• pp.111-121
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• 2005

지상용 장비의 주 동력원으로 사용할 수 있는 출력 100kW급 가스터빈 엔진의 연소기를 개발하여 시험하였다. 이를 위해 환형역류형 연소기와 압력선회식 연료노즐을 채택하였고, 1차원 설계와 3차원 열, 유동해석을 통하여 연소기 설계를 수행하였으며, 연료노즐 시험, 연소기 리그 시험 등을 통하여 개발된 연소기의 성능을 확인하였다. 개발된 연소기를 엔진에 장착하여 각종 환경시험을 수행한 결과, 연소기 저온 점화성능, 내구 성능 등에서 만족할 만한 결과를 도출하였으며, 개발된 연소기는 지상용 주 동력장치에 성공적으로 적용되었다.

• 한국정밀공학회지
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• 제16권9호
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• pp.34-40
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• 1999

In order to establish the design technique of the robust current controller in d.c series wound motor driver system, this paper proposes a method of the compensated Bang-Bang current control using d.c series wound motor driver system under the improperly variable load to get minimum time for the torque control. The compensated Bang-Bang current controller structure is simpler than that of PID plus Bang-Bang controller. This paper shows that a general 16 bits microprocessor is efficiently used to implement such an algorithm. The calculation time of software is extremely small when compared with that of conventional PID plus Bang-Bang controller. Both nonlinear operating characteristics of digital switching elements and describing function methods are used for the analysis and synthesis. Real-time implementation of the compensated Bang-Bang current controller is achieved. The concept of design strategy of the control and the PWM waveform generation algorithms are presented in this paper.

• Journal of Gastric Cancer
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• 제19권1호
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• pp.132-137
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• 2019

The occurrence of hiatal hernia after total gastrectomy with Roux-en-Y reconstruction is rare. We report the case of a 76-year-old man who presented with dyspnea, vomiting, and fever around 8 days after total gastrectomy with Roux-en-Y reconstruction. Abdominal computed tomography revealed a hiatal hernia containing part of the small intestine in the left thoracic cavity. Emergent reduction and repair of the hiatal hernia were performed later. Operative findings revealed that the Roux limb was incarcerated in the left pleural cavity. Esophagojejunostomy leakage, perforation of the small intestine with transient ischemic change, and pyothorax were also found. Thus, feeding jejunostomy, thoracoscopic decortication, and diversion T-tube esophagostomy were performed. Considering that the main cause of hiatal hernia is blunt dissection with division of the phrenoesophageal membrane, approximating the crus with 1 or 2 figure-8 sutures, according to the size of the defect, to prevent the incidence of hiatal hernia after total gastrectomy may be performed.

• 과학교육연구지
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• 제34권2호
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• pp.396-404
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• 2010

이 연구는 전국 초등학교의 영재학급이나 지역교육청 영재교육 센터에서 영재학생들을 대상으로 현재 가르치고 있거나 과거에 가르친 경험이 있는 교사 122명을 대상으로 과학의 본성에 대한 인식과 본성에 대한 교수 태도를 알아보기 위한 것이다. 이 연구에는 Chen(2006)이 개발한 VOSE 검사지가 이용되었다. 과학의 본성에 대한 인식은 7개 영역으로 나누어 조사되었으며, 과학의 본성에 대한 교수태도에 대한 것은 5개 영역별로 조사하였다. 조사한 자료를 분석한 결과, 첫째, 과학의 본성에 대해 과학영재 지도교사들은 대체적으로 바르게 인식하고 있었다. 둘째, 과학의 본성에 대한 교수태도 측면에서는 과학영재 지도교사들은 과학의 본성에 대해 가르치고자하는 긍정적인 태도를 지니고 있음을 확인하였다. 셋째, 과학영재 지도교사들이 인식하고 있는 과학의 본성에 대한 인식 정도와 교수태도는 높은 상관을 보이지 않았다. 이러한 결과는 교사의 과학의 본성에 대한 신념이 교수학습과정에 반영되지 않을 수도 있다는 개연성을 보여주는 결과라고 할 수 있다. 이러한 결과는 교사의 과학의 본성에 대한 바른 인식뿐만 아니라 과학의 본성에 대한 교수 전략 연구가 병행되어야 함을 시사해준다.

• Archives of Pharmacal Research
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• 제23권1호
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• pp.1-16
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• 2000

Many natural products elicit diverse pharmacological effects. Using two classes of potential chemopreventive compounds, the phenolic compounds and the isothiocyanates, we review the potential utility of two signaling events, the mitogen-activated protein kinases (MAPKs) and the ICE/Ced-3 proteases (caspases) stimulated by these agents in mammalian cell lines. Studies with phenolic antioxidants (BHA, tBHQ), and natural products (flavonoids; EGCG, ECG, and isothiocyanates; PEITC, sulforaphane), provided important insights into the signaling pathways induced by these compounds. At low concentrations, these chemicals may activate the MAPK (ERK2, JNK1, p38) leading to gene expression of survival genes (c-Fos, c-Jun) and defensive genes (Phase II detoxifying enzymes; GST, QR) resulting in survival and protective mechanisms (homeostasis response). Increasing the concentrations of these compounds will additionally activate the caspase pathway, leading to apoptosis (potential cytotoxicity). Further increment to suprapharmacological concentrations will lead to nonspecific necrotic cell death. The wider and narrow concentration ranges between the activation of MAPK/gene induction and caspases/cell death exhibited by phenolic compounds and isothiocyanates, respectively, in mammalian cells, may reflect their respective therapeutic windows in vivo. Consequently, the studies of signaling pathways elicited by natural products will advance our understanding of their efficacy and safety, of which many man become important therapeuitc drugs of the future.

• 동의생리병리학회지
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• 제16권1호
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• pp.8-13
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• 2002

Jinguiyuhanjing, one of the Jing-Yue's three writings which were proofread by Lin-Yi et al. in the Song dynasty, can be regarded as the book composed of another text of Shanghanlun. The book has been quoted by some medical scholars in the Song and Jin dynasty, but it has been kept hiding by some collectors from the Yuan dynasty and has not been known to the public until republished by Shi-Jie Chen in the early Ching dynasty. As compared with Shanghanlun, Jinguiyuhanjing shows much difference in contents. Rather, it has a close similarity to Qianjinyifang(千金翼方) written by SunSaiMiao(孫思邈) in the Dang dynasty. The section 1 of Zhengzhizongcongli(證治總例), which may have edited by the man who have also edited Jinguiyuhanjing published between the Nanbei(南北) dynasty and the Sui(隋) and Tang dynasty, has a lot of resemblance to Qianjinyifang. Though the book and Qianjinyifang might have come from the same version, it seems that the edition and publication of Jinguiyuhanjing have no direct relation to those of Qianjinyifang because the former has more articles and prescriptions than the other has. Jinguiyuhanjing gives a great deal of attention to scholars who study the taxt of the Song dynasty because the contents of the book particularly reveals a considerable difference to Shanghanlun published in the Song dynasty. Despite all the importances that the book have, however, no one in Korea did not pay attention to the book ever before. We are sure that it is a valuable work to introduce and study the book in Korea.

• Journal of Korean Dental Science
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• 제3권1호
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• pp.11-16
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• 2010

Objective : This prospective study sought to verify the stability of three types of short implants measuring 7mm or less. Materials and methods : Implants measuring 7mm or less were placed in patients at multicenter dental clinics in Korea, China, Taiwan, and Singapore. Initial stability, intraoperative and postoperative complications, crestal bone loss, and survival rate of the implant were prospectively evaluated. Results : The primary stability of a 6-mm implant was lower than that of a 7-mm implant. The marginal bone loss of short implants measuring less than 7mm was minimal. Complications such as wound dehiscence, implant mobility, and peri-implant mucositis developed, and these were associated with initial implant failure. The short-term survival rate of 6-mm implant was 93.7%, and that of 7-mm implant, 96.6%. Conclusion : Short implant for the mandible with insufficient height for the residual ridge can be selectively used. Poor primary stability and wound dehiscence can cause osseointegration failure and alveolar bone loss.

• Asian Pacific Journal of Cancer Prevention
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• 제15권11호
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• pp.4563-4566
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• 2014

Background: To evaluate relationship between the cyclooxygenase-2 promoter 765G/C polymorphism and digestive cancer risk in China. Materials and Methods: A literature search through February 2014 was performed using PubMed, Chinese Biomedical Literature Database (CBM) and China National Knowledge Infrastructure (CNKI) databases, and a meta-analysis was performed with RevMan 5.2 software for odds ratios and 95%CIs. Results: In total, 9 articles with 3,263 cases and 4,858 controls were included in this meta-analysis. The pooled OR (95%CIs) in the co-dominant model (GC vs GG) was 1.56 [1.19, 2.06], and in the dominant model ((CC+GC) vs GG), the pooled OR was 1.59 [1.21, 2.09] in overall cancers. In the subgroup analysis, stratified by cancer type, significant associations were found that the-765C allele had increased pancreatic cancer and gastric risk. No significant liver cancer and colorectal cancer risk of COX-2 -765G/C polymorphism was found. Conclusions: These findings suggest that COX-2-765*C is related to cancer susceptibility and may increase gastric and pancreatic cancer risk.

• Parasites, Hosts and Diseases
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• 제55권4호
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• pp.417-420
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• 2017

Hookworm infections are rare causes of acute gastrointestinal bleeding. We report a middle aged man with primary nephrotic syndrome and pulmonary embolism. During the treatment with steroids and anticoagulants, the patient presented acute massive hemorrhage of the gastrointestinal tract. The results of gastroscopy showed red worms in the duodenum. Colonoscopy and CT angiogram of abdomen were unremarkable. Capsule endoscopy revealed fresh blood and multiple hookworms in the jejunum and ileum. Hookworms caused the acute intestinal bleeding. The patient responded well to albendazole. Hematochezia was markedly ameliorated after eliminating the parasites. Hence, hookworm infection should be considered in the differential diagnosis of a patient with obscure gastrointestinal bleeding. Capsule endoscopy may offer a better means of diagnosis for intestinal hookworm infections.

• Toxicological Research
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• 제17권
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• pp.139-144
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• 2001

Chewing betel quid is associated with an increased risk of oral cancer. The betel quid chewed in Taiwan includes the inflorescence of Piper betle, which contains high concentrations of safrole (15 mg/fresh weight). Piper betle leaf is also used in betel quid; however, the concentration of safrole in betel leaf has not been documented. Chewing betel quid may contribute to safrole exposure in man (420 mm in saliva). Using $a^{32}$P-postlabeling method, we have recently demonstrated the presence of stable safrole-like DNA adducts in human oral tissues following betel quid chewing. Safrole is a rodent hepatocar-cinogen, and the real nature of safrole-DNA adducts in human tissues beside oral has not been elucidated. In this paper, we tested the safrole DNA adducts forming potential in human hepatic and oral derived cells by the ${32}^P$-postlabeling technique. The results suggest that oral cancer derived cell OC-2 alone is not able to form safrole-DNA adduct. However, safrole DNA adducts can be detected following I'-hydroxysafrole, a proximate safrole metabolite, treatment. In addition, pretreament of cytochrome P450 inducers also enhanced the formation of previously undetectable safrole DNA adducts. This finding couples with our previous results suggest that oral may serve as a target tissue for safrole, and safrole may be involved in oral carcinogenesis.