• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.193-207
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• 1999

The purpose of this study was to compare the clinical results of guided tissue regeneration(GTR) using a resorbable barrier manufactured from an copolymer of polylactic acid (PLA) and polylaetic-glycolic acid(PLGA) with those of nonresorbable ePTFE barrier. Thirty two patients(25 to 59 years old) with one radiographically evident intrabony lesion of probing depth ${\geq}$6mm participated in a 6-month controlled clinical trial. The subjects were randomly divided into three independent groups. The first group(n=8) received a ePTFE barrier. The second group (n=12) received a resorbable PLA/PLGA barrier. The third group (n=12) received a resorbable PLA/PLGA barrier combined with an alloplastic bone graft. Plaque index (PI), gingival index(GI), probing depth(PD), gingival recession, clinical attachment level(CAL), and tooth mobility were recorded prior to surgery and at 3, 6 months postsurgery, Statistical tests used to analyze these data included independent t-test, paired t-test, one-way ANOVA. The results were as follows : 1. Probing depth was significantly reduced in all groups at 3, 6 months postsurgery and there were not significant differences between groups. 2. Clinical attachment level was significantly increased in all groups at 3, 6 months postsurgery and there were not significant differences between groups. 3. There were not significant differences in probing depth, clinical attachment level, gingival recession, tooth mobility between second group (PLA/PLGA barrier) and third group (PLA/PLGA barrier combined with alloplastic bone graft) 4. Tooth mobility was not significantly increased in all groups at 3, 6 months postsurgery and there were not significant differences between groups. In conclusion, PLA/PLGA resorbable barrier has similar clinical potential to eP'IFE barrier in GTR procedure of intrabony pockets under the present protocol.

• Applied Biological Chemistry
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• 제32권4호
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• pp.435-440
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• 1989

Alkaline protease를 생산하는 Bacillus subtilis를 $100{\mu}g/ml$ NTG 처리하여 $Arg^-,\;Try^-,\;His^-\;Ade^-$ 영양요구성주를 분리하였다. 원형질체 형성은 대수증식기의 균체를 lysozyme $200{\mu}g/ml$로 $42^{\circ}C$에서 $10{\sim}30$분간 처리하였을 때 약 99%였다. 재생배지에 0.3M sodium succinate, polyvinylpyrrolidone 2.0%, casamino acid 0.5%, $10mM\;MgCl_2$ 및 $20mM\;CaCl_2$를 첨가했을 때 재생율은 25.2% 였다. 원형질체 융합은 40%(w/v)의 PEG 6,000 용액을 상온에서 $1{\sim}5$분간 처리시 약 $2{\sim}8{\times}10^{-5}$의 융합빈도를 얻을 수 있었다.

• 한국약용작물학회지
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• 제12권6호
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• pp.494-499
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• 2004

체세포배발생을 이용한 가시오갈피 대량증식체계 확립을 위하여 저온처리에 의한 체세포배의 장기저장 실험을 수행하였다. 현탁배양 체세포배의 $4^{\circ}C$에서의 저온저장에는 구형배 이전의 조기단계의 체세포배가 적합하였고 $2\;g/{\ell}$ 이하의 낮은 접종밀도에서는 36개월 이상 저장이 가능하였다. 장기간 저온 저장한 체세포배는 상온에 옮긴 후 2,4-D를 첨가한 배지에서만 성장을 회복하여 배발생캘러스를 형성하였으며 배발생캘러스의 증식속도는 배양온도를 $32^{\circ}C$로 높였을 때에 가장 효율적이였다.

• 폴리머
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• 제29권2호
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• pp.198-203
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• 2005

용융 압출 발포에 의하여 폴리락틱산(PLLA) 지지체를 제조하고 발포 조건이 지지체의 구조와 기계적 특성에 미치는 영향을 살펴보고 이를 염 추출법에 의하여 제조된 지지체와 비교하였다. 발포제를 함유한 PLLA 용융체가 압출기 및 다이에서 체류하는 시간이 발포제의 무게를 최대로 감소시키는 시간과 일치하여야 최적의 PLLA 지지체의 구조를 얻을 수 있음을 확인하였다. PLLA지지체의 구조를 유지하기 위해서는 발포제의 함량을 $10\;wt\%$ 이하로 조절해야 하며 PLLA 지지체의 다공도는 PLLA의 압출기에서의 체류시간에 가장 큰 영향을 받음을 알 수 있었다. 용융 압출 발포에 의하여 얻어진 지지체는 일반적으로 염 추출법에 의하여 제조된 지지체보다 다소 낮은 다공도를 갖지만 발포 조건의 조절에 의하여 적절한 다공 크기와 다공의 연결성을 가지며 동시에 우수한 기계적 특성을 가져 경조직 재생(hard tissue regeneration)용으로 사용이 가능할 것으로 사료된다.

• 한국환경과학회지
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• 제17권11호
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• pp.1255-1263
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• 2008

The efficiency of PP-g-AA and PP-g-St nonwoven fabric synthesized by photoinduced polymerization as an adsorbent for removal $NH_3-N$ from waste water was evaluated. The results evidently indicate that the adsorption capacities of $NH_3-N$ onto PP-g-AA nonwoven fabric were extremely superior to those onto sulfonated PP-g-St nonwoven fabric, PK and zeolite. PP-g-AA nonwoven fabric showed the maximum adsorption capacity of $NH_3-N$ at the degree of grafting of 80 wt.%. The adsorption behaviour of $NH_3-N$ onto PP-g-AA and sulfonated PP-g-St nonwoven fabric was controlled by an ion exchange reaction, and tended to be similar to both trends of Langmiur and Freundlish isotherm. Futhermore, PP-g-AA non-woven fabric could be regenerated more than 5 times by a simple washing with 0.1N HCl with no decrease of adsorption capacity and no degradation of physical properties. Also sulfonated PP-g-St nonwoven fabric could be regenerated by washing with 0.1N ${H_2}{O_4}$. However, their regeneration efficiency was significantly low because grafting layer acted as functional radical for adsorption was continuously desquamated in the adsorption or regeneration processes, which resulted in decrease of adsorption capacity and weight of adsorbent. All results obtained from this study indicate that the $NH_3-N$ removal capacity of PP-g-AA non-woven fabric was extremely superior to those of PP-g-St non-woven fabric, PK and zeolite.

• 대한치과의사협회지
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• 제47권6호
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• pp.364-372
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• 2009

치주 질환으로 인하여 소실된 치주조직을 재생시키려는 여러 술식이 많이 연구되고있다. 그 중 bioactive factor의 적용은 치주조직의 재생에 있어서 우수한 치료법으로 평가되고 있으며, 이를 수용부에 적절히 적용하기 위한 운반체로 생체친화적인 중합체가 이용되고 있다. 본 연구의 목적은 PLGA를 Inorganic filler에 혼합시킨 재료를 성견의 일벽성 골내낭에 적용하여 이 재료의 생체 친화성과 생체 흡수도를 보고자 하는 것이다. 5마리의 비글견에서 제 3 소구치를 모두 발치한 뒤, 8주간의 치유기간이 지나고 제 2 소구치 원심면과 제 4 소구치 근심면에 5mm 깊이, 4mm폭의 일벽성 골내낭을 형성하였다. 좌측 defect에는 PLGA/inorganic filler matrix를 이식하였고 우측에는 아무것도 이식하지 않은 대조군으로 나누어 술 후 8주에 희생하여 치유 결과를 조직학적으로 비교 관찰하였다. 조직학적 분석 결과, 모든 결손부에서 염증의 소견이 관찰되지 않았으며 치근흡수와 유착은 발견되지 않았다. 백악질과 치조골, 치주인대를 포함한 치주조직의 재생에 있어서 대조군, 실험군 간에 조직학적으로 치유양상에 있어 차이를 많이 보이지 않았으며 PLGA/inorganic filler matrix는 8주 내에 완전히 흡수되어 결합조직이나 신생골내에서 그 흔적을 발견할 수 없었다. 이러한 결과는 PLGA/inorganic filler matrix는 생체친화성 및 생체흡수성이 우수한 재료로서 치주 조직의 재생 치료에 있어서 신체활성인자의 scaffold로 사용될 수 있는 가능성을 보여주었다.

• Journal of Plant Biotechnology
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• 제45권1호
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• pp.55-62
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• 2018

In the present study in vitro mutagenesis was used to study the effect of gamma irradiation and EMS on callus induction, morphogenesis and production of multiple shoots from different explants of Citrullus colocynthis (L.) Schrad. Gamma radiations (5 kR to 20 kR) and certain chemicals have been effected on plant growth developments and changes of biochemical metabolisms in plants. Murashige and Skoog (MS) medium containing with auxins such as NAA, IAA, 2,4-D (0.5 ~ 2.0 mg/l), cytokinines BAP, kn TDZ, (0.5 ~ 2.5 mg/l), L-Glutamic acid (1 ~ 2 mg/l) and Coconut milk (10 ~ 20%). After 5 weeks on induction media, explants and callus (EC) were exposed to 5 kR, 10 kR, 15 kR and 20kR, of gamma radiation and treated with 1, 2, 3, 4 and 5 mM ethyl methane sulphonate (EMS) for 30 min. The highest percentage of callusing was observed (70%) stem irradiated with 5 kR and significantly decrease in fresh and dry weight of callus in the below 4 kR doses and above 20 kR doses, there was a progressive decrease in the fresh weight and dry weights when compared to control callus. Maximum percentage of plantlet regeneration (59%) was induced from callus exposed to 15 kR gamma irradiation on MS media fortified with 2.0 mg/l 2,4-D + 2.0 mg/l BAP + 2.0 mg/l L-glutamic acid. Increase in gamma irradiation dose above 15 kR and 5 mM EMS reduced regeneration capacity of callus. Doses higher than 20 kR and 7 mM EMS was lethal to micropropagated plants of Citurullus colocynthis.

• 한국결정성장학회지
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• 제27권6호
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• pp.303-308
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• 2017

여러 가지 금속을 에칭하기 위하여 사용된 $FeCl_3$ 폐용액은 유가금속인 니켈을 함유하고 있다. 본 연구에서는 염화철을 재생하고 남은 니켈 함유 에칭폐액으로부터 니켈을 고순도의 탄산니켈 결정분말로 회수하고자 하였다. 5 % NaOH 수용액을 이용하여 pH 4의 조건에서 1차적으로 철 성분의 불순물을 약 97 % 제거하고 추가적으로 남은 불순물을 제거하기 위하여 용매추출제 D2EHPA(Di-(2-ethylhexyl) phosphoric acid)를 사용하여 불순물로서 존재하는 금속이온들을 약 99% 제거하였다. 그 후 불순물이 제거된 염화니켈 용액에 탄산나트륨과의 반응을 통하여 99.9 % 이상의 순도를 가진 탄산니켈분말을 얻을 수 있었다.

• Journal of Periodontal and Implant Science
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• 제35권3호
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• pp.703-718
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• 2005

The purpose of this study was to evaluate the clinical efficacy of guided tissue regeneration(GTR) technique using chitosan nanofiber membrane and to compare it to the clinical efficacy following GTR using PLA/PLGA(copolymer of polvlactic acid and polylacticglycolic acid) membrane in mandibular class II furcation defects in human. The chitosan nanofiber membranes were applied to the mandibular class II furcation defects of 13 patients(test group) and PLA/PLGA membranes were applied to those of 11 patients(control group). Probing pocket depth, clinical attachment level, gingival recession, plaque index and gingival index were measured at baseline and 3 months postoperatively. Vertical and horizontal furcation defect depth were measured at surgery. Both groups were statistically analyzed by Wilcoxon signed Ranks Test and Mann-Whitney Test using SPSS program. The results were as follows: 1. Probing pocket depth, clinical attachment loss and gingival index were significantly reduced at 3 months postoperatively compared to values of baseline in both groups(p<0.05). 2. Gingival recession and plaque index were not significantly decreased at 3 months postoperatively compared to values of baseline in both groups. 3. No significant difference between two groups could be detected with regard to changes of probing pocket depth, gingival recession, clinical attachment level, plaque index and gingival index at 3 months postoperatively. In conclusion, chitosan nanofiber membrane is effective in the treatment of human mandibular class II furcation defects and a longer period study is needed to fully evaluate the outcomes.

• Journal of Plant Biotechnology
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• 제5권2호
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• pp.87-93
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• 2003

Brachiaria (Poaceae) is the most important forage genus for cattle production in Brazil. The genetic breeding of this genus is limited by the incompatibility among species, differences in ploidy level and the natural cloning of plants by apomixis (Valle and Miles 1992). However, plant regeneration via tissue culture methods and genetic engineering provide an opportunity to introduce new characteristics in plants of this genus. We have developed methods for the 'genetic modification of Brachiaria brizantha cv. Marandu via biolistic transformation. A higher number of shoots was obtained with 4 mg/L 2.4-diclorophenoxyacetic acid and 0.2 mg/L benzylaminopurine in calli induction medium and 0.1 mg/L naphtaleneacetic acid and 4.0 mg/L kinetin in shoot regeneration medium. A selection curve for mannose was determined to use phospho mannose isomerase (PMI) gene of Escherichia coli as a selection marker. Calli formation was inhibited from 5 g/L mannose, even in the presence of sucrose while calli that were formed in the presence of mannose failed to develop embryos showing that PMI gene can be used for selection of transformants of this grass. Different promoters were tested to evaluate the efficiency based on the detection of the GUS gene expression (Jefferson et al. 1987). The monocot promoters, act1-D and ubi-1, resulted in higher expression levels than dicot promoters, ubi-3 and act-2, or the CaMV35S and CVMV promoters.