• Title/Summary/Keyword: VAC

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Effect of Vinylic Monomers on Toughness of Unsaturated Polyester (불포화 폴리에스테르 수지의 강인성에 비닐계 단량체가 미치는 효과)

  • 이동호;정용균;최관영;김호겸;민경은;서관호;임정철;전일련
    • Polymer(Korea)
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    • v.25 no.3
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    • pp.375-384
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    • 2001
  • We investigated the change of mechanical properties of UP using mixture of SM with VAc or MA that have low glass transition temperature when polymerized instead of SM only for diluents of UP. In case of using mixture of SM/MA, it was elucidated that the toughness of UP was more improved than using SM only. But in case of SM/VAc, it was observed that the content of mixture could not affect on toughness. It was concluded that these results are caused by the effect of each diluents mixtures on stress-relaxation due to phase separation and on decrease glass transition temperature of UP is quite different from each other.

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Copolymerization of N-Vinylurea and Vinyl Acetate (Ⅰ). Synthesis of N-Vinylurea-Vinylalcohol Copolymer (N-비닐尿素와 醋酸비닐의 混成重合 (第1報). N-비닐尿素-비닐알코올混成重合體의 合成)

  • Woo Sik Kim;Hak-ki Lee
    • Journal of the Korean Chemical Society
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    • v.24 no.1
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    • pp.73-79
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    • 1980
  • N-Vinylurea(VU) was radically copolymerized with vinyl acetate (VAc). VU-vinyl alcohol (VA) copolymer, which is a water-soluble polymer with pendent urea and hydroxyl groups, was synthesized by the methanolysis of the VU-VAc copolymer.VU shows vinyl polymerization, and this result is in agreement with that of Nozakura, et al. Huggins constant for the aqueous solution of the VU-VA copolymer containing more than about 30 mole percent of VU was observed to be a high value.

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Construction of Novel Plasmid Vector for DNA Immunization

  • Park, Yeong-Seop;Park, Jae-Yeong;Jeong, Dong-Geon;Choe, Cha-Yong;Ju, Hyeon
    • 한국생물공학회:학술대회논문집
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    • 2002.04a
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    • pp.543-547
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    • 2002
  • DNA vaccines use eukaryote expression vectors to produce immunizing proteins in the vaccinated host and it represents a novel approach to vaccine and immuno-therapeutic development. We constructed a 2.9 kb compact plasmid vector (pVAC) which contains CMV promoter, polycloning site, BGH poly A terminator, ampicillin resistance gene and PBR322 origin. Enriched unmathlyated CpG motifs have introduced into pVAC-ISS1 and pVAC-ISS2 which are derived from pVAC for enhancing Thl responses. These plasmid DNAs rapidly induced interleukin 6 secretion in vivo. It is expected that these vectors will contribute to the DNA inoculation against infectious disease and various cancers without adjuvant.

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Effect of protective colloid on the synthesis of Poly(Vinyl acetate-co-Ethyl acrylate) (Poly(VAc-co-EA) 공중합체 제조에 있어 보호콜로이드의 영향에 관한 연구)

  • Kim, Nam-Seok;Kim, Sung-Hoon
    • Journal of the Korean Applied Science and Technology
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    • v.27 no.2
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    • pp.216-221
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    • 2010
  • Polyvinyl acetate (PVAc) prepared by emulsion polymerization has broad applications for additive such as paint binder, adhesive for wood and paper due to its low glass transition temperature which help to plasticize substrate resins. Since emulsion polymerization has a disadvantage that surfactant and ionic initiator degrade properties of the product polymer, poly (vinyl acetate-eo-ethyl acrylate) (VAc-EA) was synthesized using potassium persulfate as catalyst and polyvinylalcohol (PVA) as protective colloid to prevent the degradation. The copolymer latex product was internally plasticized and has enhanced adhesion, water resistance during VAc-EA emulsion polymerization. No coagulation and complete conversion occur with the reactant mixture of 10 mmol/L potassium persulfate, 10 mmol/L poly ( vinyl alcohol) (PVA 17). As the concentrations of PVA increase, the viscosity becomes increase.

Vacuum Assisted Closure Therapy in Snake Bite Wound: Preliminary Report (독사 교상 환자에서의 음압요법: 예비보고)

  • Song, Woo-Jin;Choi, Hwan-Jun;Kang, Sang-Gue
    • Archives of Plastic Surgery
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    • v.38 no.1
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    • pp.121-126
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    • 2011
  • Purpose: Vaccum-assisted closure (VAC) has rapidly evolved into a widely accepted treatment of contaminated wounds, envenomations, infiltrations, and wound complications. This results in a sealed, moist environment where tissue is given the opportunity to survive as edema is removed and perfusion is increased. Many plastic surgeons now place a VAC device directly over the fasciotomy site at the time of the initial procedure. Large amounts of the fluid are withdrawn, and fasciotomies can be closed primarily sooner. This study was designed to observe the effect of VAC in preventing complications in snake bitten hands. Methods: In our study of three cases of snake bite, three of them underwent the VAC treatment & fasciotomy of the wound in the hand. This cases, the posterior compartment of the hand was bitten for a few days, releasing incisions were made of the posterior hand and 125 mmHg of continuous vacuum was applied to fasciomy incision site and the biting wound. The dressings were changed three times per week. Results: Our study examining the effects of applied vacuum in preventing snake bite wounds showed that the incidence of tissue necrosis and compartment syndrome was significantly lower for vacuum-treated wounds than for conservative wounds. Serum myoglobin, CK-MB, and CPK levels measured after fasciotomy incision were significantly decreased. We obtained satisfactory results from early dorsal fasciotomy, drainage of the edema with the VAC system, and then primary closure. The postoperative course was uneventful. Conclusion: Envenomation is a term implying that sufficient venom has been introduced into the body to cause either local signs at the site of the bite and/or systemic signs. Use of the vacuum-assisted closure device in snake bite can result in a decreased rate of tissue necrosis, lymphatic fluid collection, hemolytic fluid collection, and edema. Early fasciotomy of the dorsal hand and VAC apply is the alternative treatment of the snake bite.

Dynamics of Bacterial Communities of Lamb Meat Packaged in Air and Vacuum Pouch during Chilled Storage

  • Wang, Taojun;Guo, Huiyuan;Zhang, Hao;Ren, Fazheng;Zhang, Ming;Ge, Shaoyang;Luo, Hailing;Zhao, Liang
    • Food Science of Animal Resources
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    • v.39 no.2
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    • pp.209-221
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    • 2019
  • In this study, the changes in microbial communities of lamb meat packaged in the air (plastic tray, PT) and in a vacuum pouch (VAC) were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) during the storage at $4^{\circ}C$. For the PT lamb, the total viable count (TVC) was $10^7CFU/g$ on Day 5, and the dominated bacteria were Pseudomonas fragi, P. fluorescens, and Acinetobacter spp. For the VAC lamb, the TVC was $10^7CFU/g$ on Day 9, and the dominated bacteria were lactic acid bacteria, including Carnobacterium divergens, C. maltaromaticum, and Lactococcus piscium. One strain of Pseudomonas spp. also appeared in VAC lamb. The relative abundance of Enterobacteriaceae in VAC lamb was higher than that PT lamb, indicating a more important role of Enterobacteriaceae in spoilage for VAC lamb than that of PT lamb. The microbial compositions changed faster in the lamb stored in a PT than that stored in a VAC, and microbial community compositions of the late storage period were largely different from those of the early storage period for both the conditions. The findings of this study may guide improve the lamb hygiene and prolong the shelf life of the lamb.

The Application of Vacuum-Assisted Closures According to the Texas Staging System in the Treatment of Infective Diabetic Foot Ulcers (감염성 당뇨 족부 궤양 치료에서 Texas 기준 체계에 따른 음압치료 적용)

  • Lim, Seong-An;Choi, Yong-Soo;Jang, Young-Jae;Baek, Sung-Nyun;Bae, An-Na
    • Journal of Korean Foot and Ankle Society
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    • v.26 no.2
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    • pp.66-70
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    • 2022
  • Purpose: A group of patients who were hospitalized for diabetic foot ulcers was classified according to the University of Texas Staging System for Diabetic Foot Ulcers, and we attempted to evaluate whether this staging system could be a criterion for treatment success using vacuum-assisted closure (VAC) technique. Materials and Methods: A total of 32 patients were diagnosed with diabetic foot ulcers according to the University of Texas Staging System for Diabetic Foot Ulcers. Of these, 24 patients who were evaluated as stage B according to the staging system were classified as Group 1, and 8 patients in stage D were classified as Group 2. After applying VAC, the treatment success rate was compared by evaluating the size and severity of ulcers between the two groups. Results: The grade of granulation after VAC was on average 3.75±0.53 in Group 1 and 2.25±0.71 in Group 2. There was better granulation after VAC application in Group 1 (p<0.01). The success rate of the treatment was 22 cases (91.67%) in Group 1 and one case (12.5%) in Group 2. Thus there were statistically significant differences in the success rate of treatment between groups 1 and 2 (Pearson's chisquare test, p=0.01; odd ratio 77.00, 95% confidence interval [CI] 1.26~14.66; relative risk 4.30, 95% CI 1.26~14.66). Conclusion: These results suggest that there was a higher success rate of treatment with VAC in stage B patients. The University of Texas Staging System for Diabetic Foot Ulcers can thus be an index for applying VAC to patients with infective diabetic foot ulcers.

Association between Genotypes and Gastric Mucosal Lymphocytes in Helicobacter pylori-infected Children (Helicobacter pylori 감염 소아에서 유전형과 위점막 림프구)

  • Yom, Hye-Won;Cho, Min-Sun;Lee, Mi-Ae;Seo, Jeong-Wan
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.12 no.2
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    • pp.140-149
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    • 2009
  • Purpose: Helicobacter pylori infection is probably acquired in childhood and persists as an asymptomatic infection for decades in most individuals. It is unclear why only a minority of those infected develop a clinical manifestation, even in childhood, such as peptic ulcer disease. H. pylori infection activates local immune responses and causes lymphocyte infiltration in the gastric mucosa. We have previously reported that both T and B cells in the lamina propria play important roles in the local immune response of H. pylori-infected children. The aim of this study was to investigate the association between H. pylori genotypes and gastric mucosal lymphocytes. Methods: Twenty-five H. pylori-infected children (10 with peptic ulcer disease and 15 with gastritis) were enrolled in this study. We investigated the genotypes (cagA, cagE, vacA, and babA2) and evaluated the association with clinical manifestations, histopathology, and gastric mucosal lymphocytes. Results: The prevalence of cagA, cagE, vacA s1m1, and babA2 was 80%, 60%, 84%, and 88%, respectively. The most prevalent (68%) combination of cagA, vacA, and babA2 genotypes was cagA+/vacA s1m1+/babA2+. H. pylori genotypes were not associated with clinical manifestations, histopathology, or gastric mucosal lymphocytes. Conclusion: There was no association between the cagA, cagE, vacA, or babA2 status and gastric mucosal lymphocytes. The role of the host immune response in relation to H. pylori genotypes and disease potential in children needs further studies.

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Comparative Proteome Analysis of Zerumbone-treated Helicobacter pylori (Zerumbone 처리에 따른 Helicobacter pylori의 단백질 비교분석)

  • Kim, Sa-Hyun
    • Korean Journal of Clinical Laboratory Science
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    • v.50 no.3
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    • pp.275-283
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    • 2018
  • Helicobacter pylori is a causative organism of various gastrointestinal diseases, including chronic gastritis, gastric ulcer, or gastric adenocarcinoma. Pathogenic factors, such as cytotoxin-associated protein A (CagA) and vacuolating cytotoxic protein A (VacA), play a role. This study analyzed qualitatively and quantitatively the effects of zerumbone on the changes in the protein expression levels of various H. pylori proteins, including CagA and VacA. Approximately 200 significant proteins were screened for the H. pylori 60190 (VacA positive / CagA positive; Eastern type) strain, and proteomic analysis was performed on 13 protein molecules that were clinically significant. After two-dimensional electrophoresis (2-DE), $ImageMaster^{TM}$ 2-DE Platinum software was used for quantitative measurements of protein spots. Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-TOF-MS) and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) were used for protein identification. After intensive analysis of the proteins that showed significant changes, a reverse transcription-polymerase chain reaction was performed as required to verify the results. In this study, the significance of zerumbone as a therapeutic agent for H. pylori infection was examined by screening a new pharmacological activity mechanism of zerumbone.