• 한국기계기술학회지
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• 제13권4호
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• pp.143-148
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• 2011

This study analyzes the resistance spot weldability of DP60 steels. To analyze the resistance spot weldability of DP60 steels, tensile strength test and macro-section test were conducted for the resistance spot welds. Acceptable welding conditions were determined as a function of the resistance spot welding process parameters such as electrode force, welding time, and welding current. The lower limit of the welding lobe was the minimum shear tension strength for 590MPa-grade steel while the upper limit was determined whether or not expulsion was detected.

• 드라이브 ㆍ 컨트롤
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• 제18권2호
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• pp.32-37
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• 2021

The piston reservoir is mainly used in hydraulic blow-down system for aerospace engineering. The reservoir is heavy due to both hydraulic cylinder and piston in pressurization. The positive expulsion tank with rubber diaphragm has been mostly applied propellant and fuel tank at low pressure to satellites. To reduce weight, the reservoir that can be used at high pressure with rubber diaphragm was developed. In this research, the prediction of life-time for the rubber diaphragm was implemented through an accelerated life test, as a part of development of new reservoir. Also, the diaphragm was stored in an temperature chamber at the same condition as and operation with hydraulic oil. As a result, the life-time for a rubber diaphragm was successfully evaluated via Arrhenius law and Time-Temperature Superposition based on failure times over temperatures in the accelerated test.

• Bulletin of the Korean Chemical Society
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• 제9권4호
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• pp.248-251
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• 1988

Mechanism of electrochemical polymerization of pyrrole (Py) on a Pt electrode in acidic aqueous solutions was studied by means of potentiostatic measurements, cyclic voltammetry and chronopotentiometry. Pyrrole molecule appeared to be initially oxidized via two-electron transfer step to produce oxidized pyrrole ion ($Py^+$), which was coupled with a non-oxidized pyrrole to yield a dimerized species, Py-Py. The Py-Py thus formed was further oxidized again via two-electron transfer step, which was followed by coupling with non-oxidized monomer and by concomitant expulsion of a $H^+$. Then the latter chain extension process was repeated. The chain extension and polypyrrole oxidation reactions occurred competitively.

• Journal of Korean Neurosurgical Society
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• 제66권5호
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• pp.591-597
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• 2023

Cervical disc arthroplasty (CDA) has become more widespread and diverges from the conventional technique used in anterior cervical fusion for cervical degenerative disc disease. As arthroplasty has become a popular treatment option, few complications have been reported in the literature. These include subsidence, expulsion, posterior avulsion fractures, heterotopic ossification, and osteolysis. One of the critical complications is osteolysis, but current studies on this subject are limited in terms of not elucidating the incidence, etiology, and consequences. The authors present two cases, who presented with clinical signs of gradually worsening myelopathy induced by posterior vertebral body osteolysis, 2 years after CDA. Subsequently, the patient underwent posterior decompression and fusion without prosthesis removal. Postoperatively, the clinical symptoms gradually resolved, with no severe deficits. The present rare cases highlight the osteolysis that occurs after CDA, which can cause cervical myelopathy, and suggest spine surgeons to be alert to this fatal complication.

• Journal of Animal Science and Technology
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• 제61권3호
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• pp.147-153
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• 2019

A goal for swine farming is the improvement in the number of live-born and weaned piglets per sow. Hence, the effect of parities should consider the correlation between the component traits of reproductive performance, weaning, and duration. Sows were housed in farrowing pens (W 2.2 ${\times}$ D 1.8 ${\times}$ H 1.2 m) on a partially slatted plastic floor. Twenty sows used in this study were between the first and sixth parity in gilts (P1), parity 2-5 (P3), and parity 6-9 (P6). Data collection by parity was classified into three categories: (1) reproduction performance (gestation length, total number of piglets born, number of piglets live born, number of piglets stillborn, total piglet birth weight; (2) weaning traits (weaning period, number of piglets weaning, total piglets weaning weight); (3) duration traits (farrowing duration, placenta expulsion duration, time from last piglet to first placenta, average birth interval, and tail wagging behavior). Gestation length was higher in P6 than P1 and P3 of different parity sows. The maximum value in P1 and P3 was 117 days, but the median value in P6 was 117 days (p < 0.05). The total number of piglets born (p = 0.113), number of piglets live born (p = 0.118), number of still piglets born (p = 0.151), and total piglet birth weight (p = 0.117) were not affected by parity. The number of live piglets was higher than the other parities by an average of $15.6{\pm}2.1$ in P1. The duration of farrowing was the lowest at 22.2 min in P6, but the maximum value was 42.2 min more than other parities (p = 0.355). Weaning traits of sows also did not differ significantly (p > 0.05), but the weaning period from P1 was lower than that of the other parities (p = 0.170). The number of piglets weaned was 10 heads on average in P1, P3, and P6 (p < 0.05). However, the mean values of the total piglet weaning weight (p = 0.377) of P6 (62.0 10.4 kg) were higher than those of P1 (54.9 10.2 kg) and P3 (58.4 13.6 kg). The placenta expulsion duration was higher in P6 than that in P1 and P3 (p = 0.447). The time from the last piglet to first placenta was be lower in P3 than that of the other parities (p = 0.206). The average birth interval was higher in P3 than that of the other parities (p = 0.156). Tail wagging (count) behavior was higher in P6 than in the other parities (p = 0.065). The data showed that the reproduction performance, total piglets born, and weight were higher in the gilts group, and higher in the weaning trait than that in the P6 group. This study examined the relationship between reproductive performance, birth interval and tail motion according to sow parity. Regarding duration, farrowing duration was lower in P6 than that in the other parities, but placenta expulsion and tail wagging were higher in P6 than in the other parities. Therefore, it is possible that the results from these sows could be used as basic data for effective farm management.

• 대한의생명과학회지
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• 제9권3호
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• pp.145-150
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• 2003

In the intestinal mucosa, mast cells are thought to be responsible for the expulsion of parasites. We investigated the relationship of worm expulsion and mast cells in C3H/HeN and BALB/c mice infected with Echinostoma hortense. In addition, we examined whether the worm recovery rate was associated with the strain of mice, and whether a toluidine stain and immunohistochemistry using the c-kit antibody was effective in the detection of mast cells. In order to investigate the mucosal immune response of C3H/HeN and BALB/c mice, each mouse was infected orally with 30 E. hortense metacercariae. Then, the number of mucosal mast cells and worm recovery rates was observed in experimentally infected mouse strains between 1 week and 8 weeks post infection (PI). Mucosal mast cells were increased in 3 weeks P.I. in C3H/HeN and BALB/c mice. On the other hand, only mucosal goblet cells and worm recovery rates correlated in C3H/HeN mice (P=0.0482). Worm recoveries in C3H/HeN mice were 65.7$\pm$5.6, 53.3$\pm$5.4 and 6.7$\pm$0.6 in week 1, 2, and 3 P.I. and strongly decreased in week 3 P.I. Worm recoveries in BALB/c mice were 23.0$\pm$2.5, 10.0$\pm$1.0, and 6.7$\pm$0.6% in week 1, 2, and 3 P.I. and gradually decreased from week 1 P.I. to week 3 P.I. Worm recoveries in C3H/HeN mice were significantly higher than in BALB/c mice (P<0.00l). The number of mast cells in C3H/HeN and BALB/c mice using the anti-c-kit antibody reached to a peak in week 3 P.I. and recovered as normal level in week 5 P.I. and 6 P.I. The number in E. hortense-infected C3H/HeN mice (P=0.0015) was higher than in E. hortense-infected BALB/c mice (P=0.01) compared with the control group. There were significant differences in the number of mast cells among regions of the intestine in in C3H/HeN mice (P<0.05) but not in BALB/c mice (P>0.05). Immunohistochemistry using the anti-c-kit antibody was significant method as an examination of the number of mast cells (P=0.0002). In conclusion, the present study demonstrated that mast cells play an important role in worm recovery, and immunohistochemistry using the anti-c-kit antibody was superior to toluidine stain as an examination of mast cells.

• 대한의생명과학회지
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• 제6권2호
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• pp.93-100
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• 2000

호르텐스극구흡충 피낭유충을 흰쥐 및 마우스에 경구 감염시킨 후 실험동물의 혈청 및 장액에 대한 IgA 및 IgE 항체가 변화 추이를 ELISA방법으로 비교 분석하였다. 감염 흰쥐에서 혈청의 경우 IgA와 IgE항체가를 대조군과 비교해 볼 때 유의한 차이를 나타내지 않았다. 그러나 장액의 IgA항체가는 감염 후부터 계속 증가하여 8주에서 최고치 (0.47$\pm$0.11)를 나타냈다. 감염 흰쥐에서 충체 회수율은 8주까지 계속 충체 수가 감소하는 경향을 보였는데 특히, 장액의 IgA 항체가 성적이 최고치를 나타낸 기간에 유의한 감소 성적을 나타냈다 감염 마우스 혈청에서의 IgA항체가는 감염 기간동안 계속적으로 증가하여 감염 8주에서 최고치 (0.45$\pm$0.01)를 보였으며, IgE의 경우는 감염 후부터 7주까지 증가하여 7주에서 그 최고치 (0.23$\pm$0.02)를 보였으나 그 이후 다시 감소되었다. 장액의 경우 IgA 항체가는 감염 후부터 증가하여 8주에서 최고치 (0.14$\pm$0.01)를 보였으며, 이는 혈청 IgA의 항체가 변화와 유사한 경향을 보였다. 감염 마우스의 충체 회수율은 감염 후부터 계속적으로 감소하였으며 7주와 8주에서 유의한 감소를 보였는데 (p＜0.05)이것은 장액에서의 IgA와 IgE, 혈청에서의 IgA의 항체가 최고치를 나타낸 기간과 일치하였다. 이상의 결과에서 호르텐스극구흡충 감염 마우스에 있어서, IgA 및 IgE 항체가의 유무는 충체의 배출(expulsion)에 일부 연관되어 있음을 알 수 있었다.

• Pediatric Infection and Vaccine
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• 제27권1호
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• pp.77-82
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• 2020

한국의 회충 감염률은 1970년대까지 높았으나 성공적인 기생충 관리로 매우 낮은 수준으로 감소하였다. 최근 회충 유행 지역으로부터의 인구 유입 및 해외여행 증가, 수입 농산물의 증가 등으로 인해 발생 가능성이 높아지는 가운데 성인에서 회충감염으로 장폐쇄나 췌담관 질환이 유발된 증례 보고들이 있었다. 저자들은 회충증을 의심할 만한 위험 요인이 없는 2세 남아의 기저귀에서 회충 성충이 발견된 증례를 경험하여 보고한다. 아침에 환아의 어머니가 기저귀를 갈다가 움직이는 충체를 발견하여 내원하였다. 특이 과거력 없이 평소 건강하던 환아로 이상 증상은 없었고 신체 진찰에서 특이 소견은 관찰되지 않았다. 충체는 길이 약 25 cm, 폭 5 mm의 선충으로 머리와 꼬리는 원추상을 보여 회충으로 추정하였고 대변 기생충란 검사에서 Ascaris lumbricoides의 불수정란이 확인되어 회충증으로 진단하였다. 구충제인 알벤다졸 400 mg을 1회 경구 투여 후 추적 관찰하였고 추가적인 회충 발견이나 증상 발생은 없었다. 전체적인 기생충 감염률이 감소하여 관심이 줄어드는 현실에서 회충 감염에 대한 인식을 높일 필요가 있겠다.

• 고전문학과교육
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• 제39호
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• pp.99-135
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• 2018

이 연구의 목적은 <옥환기봉>의 곽후 폐출 사건에 나타난 칠거지악 논쟁과 부부 담론을 고찰하는 것이다. 그러기 위해 먼저 조선 시대 실재했던 출처 사건과 칠거지악 논쟁의 관련성을 검토하였다. '이미'와 '신태영'의 이혼 소송, 성종의 윤씨 폐출 사건 등을 통해 볼 때, 칠거지악의 조항 대부분은 판단 기준이 불분명하거나 논쟁적이다. <옥환기봉>의 곽후 폐출 사건 역시 칠거지악 논쟁을 소설적으로 형상화하고 있다. 곽후는 투기하고 악행을 저질러 폐출되었지만, 그녀는 시부모에게 효성이 지극했고 아들을 낳았으며 무엇보다 조강지처였다. 이 과정에 대한 작가의 서술은 섬세하고 객관적이었으며, 당사자와 주변 인물들의 진술은 진정성을 가졌다. 그러니 독자들은 곽후의 폐출에 대해 선뜻 동의하기 어려웠을 것이고, 이러한 결론에 대한 문제 제기는 연작 창작으로 이어졌다. 곽후 폐출의 원인은 악행이었고, 그 원인은 투기였다. 그러나 투기의 원인은 '옥환과 음후의 존재, 광무제의 편벽된 사랑'이다. 즉 투기가 곽후만의 잘못은 아니다. 곽후의 악행에 개입하는 비현실적 요소, 곽후 중심의 서사구성도 독자들로 하여금 곽후를 옹호하게 하는 요인이다. 결국 '옥환기봉'이라는 제목은 반어적 성격을 가지며, <옥환기봉>은 '옥환'을 매개로 한 광무제와 음후의 사랑보다 당대 부부 담론의 현실을 보여준다. 이러한 의식은 연작에서도 그대로 이어지고 있으며, 현재에도 유효한 문제이다. 당대의 현실성과 오늘날의 현재성을 모두 획득하고 있다는 점에서 <옥환기봉>은 문제작이다.

• Parasites, Hosts and Diseases
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• 제38권4호
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• pp.209-236
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• 2000

The last two decades witnessed significant advances in the efforts of immune-parasitologists to elucidate the nature and role of the host mucosal defence mechanisms against intestinal nematode parasites. Aided by recent advances in basic immunology and biotechnology with the concomitant development of well defined laboratory models of infection, immunoparasitologists have more precisely analyzed and defined the different immune effector mechanisms during the infection; resulting in great improvement in our current knowledge and understanding of protective immunity against gastrointestinal (GI) nematode parasites. Much of this current understanding comes from experimental studies in laboratory rodents, which have been used as models of livestock and human GI nematode infections. These rodent studies, which have concentrated on Heligmosomoides polygyrus, Nippostrongylus brasiliensis, Strongyloides ratti/5. venezuelensis. Trichinella spiralis and trichuris muris infections in mice and rats, have helped in defining the types of T cell responses that regulate effector mechanisms and the effector mechanisms responsible for worm expulsion. In addition, these studies bear indications that traditionally accepted mechanisms of resistance such as eosinophilia and IgE responses may not play as important roles in protection as were previously conceived. In this review, we shall, from these rodent studies, attempt an overview of the mucosal and other effector responses against intestinal nematode parasites beginning with the indices of immune protection as a model of the protective immune responses that may occur in animals and man.