• International journal of advanced smart convergence
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• 제8권4호
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• pp.200-206
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• 2019

In this study, we compared the VacCAD and VacSim^(Multi), commercial vacuum simulators, to verify the advantages of VacCAD's efficiency. It was emphasized on immediacy and simplicity of simulation modelling, and characteristics of the pump combinations, pumping down curves, and vacuum materials. First, usability of simulation mechanism was estimated through the modeling schematics and obtained simulation results of each employed simulator were compared to evaluate the applicability in practice. Simulation reliability of each simulator was also probed by comparing the pumping characteristics of commercially available high vacuum systems. In addition, the degree of tolerances on VacCAD was also investigated through pumping down analysis considering outgassing effect due to chamber material variations. The higher effectiveness and expediency of VacCAD than VacSim^(Multi) has been presented, and it was expected that the utilization of VacCAD in vacuum applications to be increased.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.217-223
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• 2023

In this study, we compared the VacCAD and VacTran, commercial vacuum simulators, to investigate the simulation applicability and efficiency as vacuum simulation software. It was verified on reliability and simplicity of simulation modelling, and characteristics of the pump combinations, pumping down curves, and employed vacuum materials. First, usability of simulation schematics was estimated through the modeling tools and the overall simulation characteristics of each simulator were compared to evaluate the applicability in practice. Simulation reliability of each simulator was also probed by comparing the pumping performance characteristics of commercial high vacuum system models. In addition, the degree of tolerances on both simulators was also evaluated through pumping down analysis considering outgassing effect due to chamber material variations. The higher effectiveness and expediency of VacCAD than VacTran has been presented, and it was also expected that the utilization of VacTan in vacuum applications to be increased due to the higher availability of modelling variations.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제4권2호
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• pp.155-160
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• 2001

목적: H. pylori의 vacA 대립유전자는 종족과 지역에 따라 다양하게 나타나고 있다. 저자들은 H. pylori에 감염된 소아의 위생검조직에서 vacA 대립 유전자에 대한 중합효소연쇄반응과 유전자염기분석을 실시하여 한국의 signal sequence와 mid-region의 다형성 및 고유의 시발체를 연구하고자 하였다. 방법: 상부 위내시경을 시행한 후 H. pylori 감염으로 진단된 10~18세 50명의 환아를 대상으로 위생검조직을 이용하여 vacA 대립유전자에 대한 PCR과 DNA 분석을 실시하였다. 이들 결과와 다른 나라의 vacA 대립유전자를 비교분석하였고 우리나라의 고유한 염기배열을 갖는 시발체를 제작하였다. 결과: 1) 서구의 시발체를 사용한 50명 중 30명(60%)에서 모두 s1이 검출되었고 이중 s1a가 14명, s1c 15명, s1a/s1c hybrid가 한 명이었으며 s1b는 발견되지 않았다. s1c/m1이 가장 많은 형이었다. 2) 우리 나라에 공통으로 발견되는 염기변이가 s1a에서는 GGGAGCGTTR, s1c는 GGGGYTATTG 이었으며 이들을 이용하여 새로운 시발체를 고안하였다(VASK-F, VASK-R, S1AK-F, S1CK-F). 새로이 제작된 시발체로 처음의 50개 조직을 재검한 결과 50개 모두에서 s region이 양성이었다. 결론: 우리 나라의 주된 vacA 대립유전자형조합은 s1c/m1이었고, vacA signal sequence의 한국 고유의 시발체를 만들었음을 보고하는 바이다.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.666-672
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• 2003

Vacuolar degeneration of the gastric epithelial cells is a characteristic feature of the derangement of mucosa where Helicobacter pylori colonizes, and H. pylori vacuolating cytotoxin (VacA) has been suggested to playa key role in it. To elucidate the VacA-involved degenerative mechanism, VacA was purified, and its impact on degeneration of HeLa cells was determined. In the presence of ammonium chloride, cell vacuolation by VacA was dose-and time-dependent, however, no detectable degeneration of the cells was observed with the VacA concentration tested. A further increase of vacuolation was shown in cells pre-treated with diethyl pyrocarbonate (DEPC) , and this resulted in a change of the cell morphology to become spherical. Similar phenomena were also observed when HeLa cells were co-cultivated with intact H. pylori cells. It was remarkable to note that the degree of growth inhibition was proportional to the increase in vacuole formation, suggesting that the vacuolation rate would be critical for cell degeneration. Surprisingly, although VacA was itself inhibited by DEPC, its uptake was markedly increased by this agent, similar to that found in cells with Nabutyrate. These data indicate that the cell's tolerance of VacA transport may be critical for vacuolar degeneration and may be changeable during H. pylori inhabitation.

• 대한방사선치료학회지
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• 제30권1_2호
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• pp.27-34
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• 2018

목 적 : 폐의 우측후사방향 선량전달시, Carbon Side Rail과 환자 고정기구인 Vac-lok이 미치는 영향을 보고자 한다. 대상 및 방법 : Vac-lok의 오른쪽 부분을 10, 20, 30 mm 두께로 제작하였다. 측정은 유리선량계를 이용하여 측정하였고, 측정점은 팬텀 우측 폐의 center Point를 기준으로 좌, 우, 하, 상 방향 각각 A, B, C, D Point로 설정 하였다. 각 point에 유리선량계를 삽입한 후 couch의 Side Rail을 외측(Out)으로 뺀 후 vac-lok을 놓지 않은 no vac-lok, 그리고 10, 20, 30 mm의 vac-lok 위에 팬텀을 세팅하였다. 중심점에 6 MV 광자선을 조사야 $10{\times}10cm^2$, SAD 100 cm, 겐트리 각도 $225^{\circ}$로 하여 300 MU/min 선량률과 100 MU 조사선량을 전달하였다. 측정은 5회씩 실시하였고, 마찬가지로 Side Rail을 내측(In)으로 넣은 후 각 point에 대해서도 같은 조건으로 5 회씩 측정하여 평균값을 산출하였다. 결 과 : side rail에 따라서는 중심점, A, B, C, D Point 각각 -11.8 %, -12.3 %, -4.1 %, -12.3 %, -7.3 %의 선량 감소를 보였다. Side-Rail-Out에서 10 mm vac-lok의 경우 약 -0.9 %가 감소되었고, 20 mm vac-lok 사용 시 약 -2.0 %, 30 mm vac-lock 사용 시 약 -3.0 %가 감소되었다. Side-Rail-In에서 10 mm vac-lok의 경우 약 -1.0 %가 감소되었고, 20 mm vac-lok 사용 시 약 -2.1 %, 30 mm vac-lok 사용 시 약 -3.0 %가 감소되었다. Side-Rail-In 상태의 no vac-lok 선량 값을 기준으로 Side-Rail-Out 상태의 10, 20, 30 mm vac-lok을 사용할 때, side rail에 대한 선량 감소에 더하여 중심점에서는 약 -0.9 %, -1.8 % -2.4 %, A point에서는 -0.5 %, -1.6 %, -2.1 %, B point에서는 약 -0.9 %, -2.0 %, -3.2 %, C Point에서는 -1.0 %, -2.1 %, -3.1 %, D point에서는 약 -1.0 %, -1.6 %, -3.1 %의 추가적인 선량 감소를 나타냈다. 결 론 : 폐를 비롯한 우측후사방향 방사선 치료 시 side rail에 대해 주의를 기울이고, vac-lok 제작 시 vaclok 두께에 대해 관심을 갖는다면 더 나은 치료 효과를 기대해 볼 수 있으리라 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제8권5호
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• pp.289-293
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• 2004

To investigate whether VacA (vacuolating toxin) produced by Helicobacter pylori Korean stain 99 induces intestinal secretion, purified VacA was added to T84 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of low pH-pretreated VacA increased short circuit current (Isc). The effect was time- and dose-dependent and saturable. The time-to-peak Isc was concentration-dependent. Chloride channel inhibitors, niflumic acid or 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), inhibited VacA-stimulated Isc. Carbachol (CCh)-induced increase of Isc was prolonged by the addition of VacA to the mucosal side only. The effect was unaltered by the addition of niflumic acid. VacA did not show cytopathic effects. These studies indicate that VacA is a nonlethal toxin that acts in a polar manner on T84 monolayers to potentiate $Cl^-$ secretion and the response to CCh secretion without decrease in monolayer resistance. VacA may contribute to diarrhea diseases in human intestinal epithelial cells.

• Archives of Plastic Surgery
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• 제33권5호
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• pp.632-636
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• 2006

Purpose: Methicillin-Resistant-Staphylococcus aureus(MRSA) has been increasingly recognized as a cause of nosocomial infection. MRSA is hardly-controllable organism among the pathogen of nosocomial infection, because it is resistant to most antibiotics except vancomycin, and local treatment with most antiseptics are not effective to eradicate MRSA from the infection. The effectiveness of Vacuum-Assisted-Closure(VAC) was reported widely. we tried to modify original VAC. We tried VAC dressing on MRSA infected wound to evaluate whether or not the VAC is effective to eradicate MRSA which existed in the open wound. Methods: From September 2003 to December 2003, 24 patients admitted to the plastic and reconstructive surgery and orthopedic surgery, were studied. All patients were found to be positive in previous wound. Using clinical randomized study, 24 patients were divided into two groups: VAC dressing group and the $Betadine^{(R)}$ dressing group(control). During treatment, wound culture was done twice a week for evaluation of MRSA infection elimination. Results: The mean period that MRSA become not detected in all case was 17.1 days in VAC dressing group, and 25.8 days in control group, respectively. The p value was 0.013. The result reveals that the VAC dressing group is more effective to MRSA infection control. As a result, the VAC dressing was more effective in MRSA infected wound than conventional dressing. Conclusion: Through this study, we found objective result of VAC dressing. We hope that VAC dressing is more widely applied to fresh and infected wound.

• Toxicological Research
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• 제9권2호
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• pp.225-232
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• 1993

SCi-B-Vac, the 3rd hepatitis B vaccine , was selected for clinical evaluation on the basis of toxicologic profiles in preclinical studies. These studies were performed to obtain information on its toxic signs, organs which are mainly affected, and to estimate its lethality in mice and rats given Sci-B-Vac through two routes of administratin. In male and female rats given a single intragastrical dose of Sci-B-Vac, we estimated that $LD_{50}$ values were over 2.00 ml/100g B.W. (10ng/ml), respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권1호
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• pp.29-33
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• 2005

A DNA vaccine methodology using eukaryote expression vectors to produce immunizing proteins in the vaccinated hosts is a novel approach to the development of vaccine and immuno-therapeutics, and it has achieved considerable success over several infectious diseases and various cancers. To further enhance its efficiency, attempts were made to develop novel plasmid vectors containing multiple immunostimulatory CpG motifs, for rapid and strong immune response. First, a 2.9 kb compact plasmid vector (pVAC), containing CMV promoter, polycloning site, BGH poly(A) terminator, ampicillin resistance gene and pBR322 origin was constructed. A pVAC-hEPO was also constructed, which contained a human erythropoietin gene, for evaluating the transfection efficiency of naked plasmid DNA both in vitro and in vivo. To examine the adjuvant effect of multi-CpG motifs on naked plasmid DNA, 22 and 44 enriched and unmethylated CpG motifs were introduced into pVAC to generate pVAC-ISS1 and pVAC-ISS2, respectively. $100{\mu}g$ of pSecTagB, pVAC, pVAC-ISS1 or pVAC-ISS2 were each injected intramuscularly into the tibilias anterior muscle of Balb/c mice. The level of interleukin-6 induced in the mice injected with pVAC-ISS1 and pVAC-ISS2 were significantly elevated after 12 hours, which were almost 2 and 2.5 times higher than that in the mice injected with pSecTagB, respectively. These results suggest that DNA vaccine plasmids with enriched CpG motifs can induce rapid secretion of interleukin-6 by lymphocytes. In conclusion, these vectors can contribute to the development of adjuvant-free DNA vaccinations against infectious diseases and various cancers.

• Archives of Plastic Surgery
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• 제35권4호
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• pp.393-399
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• 2008

Purpose: Chronic infected wounds sustained over 4 weeks with exposed tendon or bone are difficult challenges to plastic surgeons. Vacuum assisted closure (VAC) device has been well used for the management of chronic wounds diminishing wound edema, reducing bacterial colonization, promoting formation of granulation tissue and local blood flow by negative pressure to wounds. But Commercial ready-made VAC device might have some difficulties to use because of its high expenses and heavy weight. So we modified traditional VAC device with silver dressing materials as topical therapeutic agents for control of superimposed bacterial wound infection such as MRSA, MRSE and peudomonas. Methods: We designed the modified VAC device using wall suction, 400 cc Hemovac and combined slow release silver dressing materials. We compared 5 consecutive patients' data treated by commercial ready-made VAC device(Group A) with 11 consecutive patients' data treated by modified VAC device combined with silver dressing materials(group B) from September 2004 to June 2007. Granulation tissue growth, wound discharge, wound culture and wound dressing expenses were compared between the two groups. Results: In comparison of results, no statistical differences were identified in reducing rate of wound size between group A and B. Wound discharge was significantly decreased in both groups. Modified VAC device with silver dressing materials showed advantages of convenience, cost effectiveness and bacterial reversion. Conclusion: In combination of modified VAC device and silver dressing materials, our results demonstrated the usefulness of managing chronic open wounds superimposed bacterial infection, cost effectiveness compared with traditional VAC device and improvement of patient mobility.