• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.149-158
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• 2010

Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzymatic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pretreatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more defiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical composition and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst.

• 한국수의병리학회지
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• 제6권1호
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• pp.41-48
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• 2002

Oval cell is considered as facultative precursor cells for both hepatocytes and biliary cells, as well as origin of hepatocellar and cholangiocellular carcinoma (CCC) during carcinogenesis or toxic liver injury. To clarify the cellular origin or differentiation of cholagiocarcinogensis, the fate of carcinogen-induced oval cells was pathologically and phenotypically chased in Syrian golden hamster liver after Clonorchis sinensis (CS) infection which would give rise to a promoting effect. Two week treatment of hamsters with 0.005% diethylnitrosamine (DEN) followed by 2 week treatment of 1% 2-acetylaminofluorene (AAF) under choline deficient diet resulted in massive proliferation of BrdU labeleed and PCNA positive oval cells showing various distinct morphology, histochemical and immunohistochemical phenotypes for GGT, cytokeratin 19 and OV-6. Oval cells also frequently form ductular-like structures or phenotypically show hepatocyte-like characteristics. After CS infection, the oval cells showed sequential morphological changes to atypicl proliferating bile ductules and all hamsters thereafter developed well differentiated and anaplastic CCC at 16 week after CS infection. In electron microscopy, some bile ductules were constructed by intermediate oval cells and bile ductular cells surrounded by basement membrane. The results of this study strongly suggest that CCC developed in the present study were originated from hepatic stem-like oval cells, supporting the theory of stem cell origin of cancers. In addition, this hamster model would be valuable for the molecular mechanistic study during chemical-triggered cholangiocarcinogenesis.

• 대한치과교정학회지
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• 제47권4호
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• pp.238-247
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• 2017

Objective: The aim of this study was to compare recycled and unused orthodontic miniscrews to determine the feasibility of reuse. The comparisons included both miniscrews with machined surfaces (MS), and those with etched surfaces (ES). Methods: Retrieved MS and ES were further divided into three subgroups according to the assigned recycling procedure: group A, air-water spray; group B, mechanical cleaning; and group C, mechanical and chemical cleaning. Unused screws were used as controls. Scanning electron microscopy, energy-dispersive X-ray spectrometry, insertion time and maximum insertion torque measurements in artificial bone, and biological responses in the form of periotest values (PTV), bone-implant contact ratio (BIC), and bone volume ratio (BV) were assessed. Results: Morphological changes after recycling mainly occurred at the screw tip, and the cortical bone penetration success rate of recycled screws was lower than that of unused screws. Retrieved ES needed more thorough cleaning than retrieved MS to produce a surface composition similar to that of unused screws. There were no significant differences in PTV or BIC between recycled and unused screws, while the BV of the former was significantly lower than that of the latter (p < 0.05). Conclusions: These results indicate that reuse of recycled orthodontic miniscrews may not be feasible from the biomechanical aspect.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1401-1411
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• 2019

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide ($H_2O_2$) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of catalase decreased the effects of the former. Mycobacteria were more resistant than E. coli to NTPJ treatment. Plasma treatment enhanced intracellular ROS production and upregulation of genes related to ROS stress responses (thiolrelated oxidoreductases, such as SseA and DoxX, and ferric uptake regulator furA). Morphological changes of M. smegmatis and M. tuberculosis H37Rv were observed after 5 min treatment with $N_2+H_2O$ plasma, but not of pre-incubated sample with catalase. This finding indicates that the bactericidal efficacy of NTPJ is related to the toxicity of OH and $H_2O_2$ radicals in cells. Therefore, our study suggests that NTPJ treatment may effectively control pulmonary infections caused by M. tuberculosis and nontuberculous mycobacteria (NTM) such as M. avium or M. abscessus in water.

• 대한한방소아과학회지
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• 제32권3호
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• pp.16-25
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• 2018

Objectives The purpose of this study is to investigate the anti-inflammatory effect of Lonicera Japonica-Glycyrrhiza Uralensis decoction extracts (LGE) on ulcerative colitis in children and adolescents. Methods Colitis was induced by DSS (Dextran Sulfate Sodium) in C57BL/6 mice. The sample mice were divided into group of four. The mice in the control group were not inflammation-induced. The control group was composed of untreated ulcerative colitis elicited mice. The mice in the experimental group were administered with Pentasa and another experimental group mice were treated with LGE after colitis elicitation. The effects on ulcerative colitis were evaluated by the morphological changes of colonic mucosa, decrease in the effect of pro-inflammatory cytokines ($TNF-{\alpha}$ and $NF-{\kappa}B$) and inflammatory cytokines (iNOS and COX-2) in the mucosa. Results LGE showed protective effects in DSS induced ulcerative colitis. LGE inhibited shortening of colon length and relieved the hemorrhagic erosion in colonic mucosa. LGE decreased pro-inflammatory cytokines ($TNF-{\alpha}$ and $NF-{\kappa}B$) and inflammatory cytokines (iNOS and COX-2). According to the GC/MS analysis, N-methyl pyrrolidone (NMP) was identified. Conclusions The result shows the clinical efficacy of LGE and demonstrates possible treatment options for ulcerative colitis. Further investigations for biological activity and chemical analysis of LGE will be needed.

• Journal of the Korean Wood Science and Technology
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• 제47권2호
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• pp.145-162
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• 2019

This study aimed to increase the sugar and ethanol yield from the mengkuang plant biomass through biological and liquid hot water (LHW) pretreatment and their combination. The results showed that biological pretreatments with 5% inoculum of the fungus Trametes versicolor resulted in the highest alpha cellulose content incubated for 30 days, and 10% inoculum resulted in the lowest lignin content. LHW pretreatment decreased the hemicellulose content of pulps from 10.17% to 9.99%. T. versicolor altered the structure of the mengkuang pulp by degrading the lignin and lignocellulose matrix. The resulting delignification and cellulose degradation facilitate the hydrolysis of cellulose into sugars. The alpha cellulose content after biological-LHW pretreatment was higher (78.99%) compared to LHW-biological pretreatment (76.85%). Scanning electron microscopy analysis showed that biological-LHW combinated treatment degrades the cell wall structures. The ethanol yield for biological-LHW pretreated sample was observed 43.86% (13.11 g/L ethanol by weight of the substrate, which is much higher than that of LHW-biological pretreatment (34.02%; 9.097 g/L). The highest reducing sugar content about 45.10% was observed with a resulting ethanol content of 15.5 g/L at LHW pretreatment temperature of $180^{\circ}C$ for 30 min.

• 한국염색가공학회지
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• 제28권2호
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• pp.70-76
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• 2016

Silver nanoparticles(AgNPs) were attached to wool fibers using glycidyltrimethylammonium chloride(GTAC), which is a type of quaternary ammonium salt. GTAC, which contains an epoxy functional group that, under high temperatures, generates a ring-opening reaction with wool fibers, which contain the amine group. Then, the AgNPs are attached to the surface of the GTAC-treated wool fibers by treatment with a silver colloidal solution. The process involves the following procedures: (1) The wool fibers are immersed in the GTAC solution, followed by pre-drying at $80^{\circ}C$ and curing at $180^{\circ}C$ to induce an alteration in the chemical structure; and (2) The wool fibers treated with GTAC are immersed in the silver colloid at $40^{\circ}C$ for 120 min to chemically induce a strong attachment of the AgNPs to the wool fibers. Scanning electron microscopy was used to analyze the influence of the concentrations of GTAC and the silver colloid, as well as the influence of the applied temperature of the silver colloid on the wool fibers, and the influence of the morphological changes in the wool fiber surfaces. As a result, the enhanced concentrations of GTAC and the silver colloid together with an elevated applied temperature of silver colloid have a tendency to increase in Ag atomic%.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권3호
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• pp.173-178
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• 2003

To improve the erythritol productivity of Penicillium sp. KJ81, mutants were obtained using UV irradiation and NTG treatment Among these mutants, Penicillium sp. KJ-UV29 revealed no morphological changes, yet was superior to the wild strain in the following three points: (1) Penicillium sp. KJ-UV29 produced more erythritol than the wild strain under the same conditions, (2) no foam was produced during cultivation, unlike the wild strain, and (3) the mutant produced a Significantly lower amount of glycerol. Penirillium sp. KJ-UV29 produced as much as 15.1 g/L of erythritol, whereas the wild-type Penirillium sp. KJ81 only produced 11.7 g/L. Penicillium sp. KJ-UV29 only generated 6.1 g/L of glycerol, compared to 19.4 g/L produced by the wild strain. When investigating the optimal culture conditions for erythritol production by the mutant strain Penicillium sp. KJ-UV89, sucrose was identified as the most effective carbon source, and the mutant was even able to produce erythritol in a 70% sucrose-containing medium, although a 30% sucrose medium exhibited the highest productivity. The production of erythritol by Penirillium sp. KJ-UV29 was also significantly increased by the addition of ammonium carbonate, potassium nitrate, and sodium nitrate. Accordingly, under optimal conditions, Penicillium sp. KJ-UV29 produced 45.2 g/L of erythritol in a medium containing 30% sucrose, 0.5% yeast extract, 0.5% (NH$_4$)$_2$C$_2$O$_4$, 0.1% KNO$_3$, 0.1% NaNO$_3$, and 0.01% FeSO$_4$ with 1 vvm aeration and 200 rpm agitation at 37$^{\circ}C$ for 7 days in a 5-L jar fermentor.

• 한국응용과학기술학회지
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• 제36권3호
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• pp.915-929
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• 2019

본 연구에서는 천연헤나 처리 후 펌(permanent wave)을 시술하여 모발의 손상도 및 형태학적 변화에 미치는 영향을 알아보기 위해 실험을 진행하였다. 실험 방법은 아미노산분석, 주사현미경측정에 의한 모발의 두께와 표면관찰, 모발의 컬 형성력과 지속력, 메틸렌블루 염색법, 인장강도와 신장률을 측정하였으며, 그 결과는 다음과 같다. 아미노산 총량은 천연헤나 처리횟수가 증가할수록 증가하였으며, 모발 보호 효과가 있을 것으로 보인다. 컬 형성력은 대조군에 비해 천연헤나 처리 횟수가 증가할수록 컬은 탄력이 있었다. 지속력은 대조군과 실험군 모두 샴푸 횟수가 많을수록 (C)와 (C)' 길이의 늘어짐이 증가하여 지속력이 감소하였으며, 주사전자현미경에 의한 모발의 두께는 대조군(Control)에 비해 실험군 모두 천연헤나처리 후 모발의 두께가 굵어졌다. 표면의 형태적 관찰에서는 실험군 모두 모발의 표면이 대체적으로 깨끗하고 큐티클 층이 잘 정돈되어 있음을 확인하였다. 또한 메틸렌블루염색법에서는 천연헤나처리 횟수가 증가할수록 흡광도 값은 증가하였다. 인장강도는 대조군에 비해 실험군 모두 인장강도가 감소하였으며, 신장률은 천연 헤나 처리횟수가 증가할수록 실험군의 신장률이 증가하였다. 이상의 결과를 종합하면 천연헤나 처리횟수가 증가할수록 모발의 두께가 굵어졌고, 모발의 컬 형성력과 지속력이 높아졌으며, 모발에 탄력성과 유연성을 부여함으로서 모발 손상을 완화 시킬 수 있음을 알 수 있었다. 따라서 본 연구의 천연헤나 시술법은 염색과 펌의 잦은 화학시술로 인한 고객의 손상된 모발을 관리하고, 미용산업 현장에 올바른 시술방법 제안으로 두피와 모발손상을 줄이는데 기초자료로 도움이 될 수 있을 것이다.

• 공업화학
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• 제31권4호
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• pp.347-351
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• 2020

재료는 방사선과 상호작용을 통해 그 물리적, 화학적 특성이 변화하며 여러 방사선 중에서 전하를 띄고 있지 않아 침투깊이가 깊은 중성자 조사에 의한 금속소재의 조사손상은 원자력발전소의 안전과 관련해서 오랜 기간 동안 집중적인 연구대상이었다. 중성자 조사에 의한 조사손상은 초반 피코 초 스케일에서 벌어지는 원자단위의 점결함의 생성으로 시작되며 그 이후의 전개 양상은 전위 고리나 공극과 같은 미세구조상 결함으로 확인될 수 있다. 이러한 미세구조 상 결함의 형상과 분포에 따라 소재의 특성에 미치는 효과는 상이하게 된다. 그러므로 중성자 조건에 따른 미세구조를 예측하는 것은 매우 중요한 일로, 본 논문에서는 중성자 조사에 의한 재료 내의 미세구조 발달에 대해 리뷰한 뒤 조사된 소재의 미세구조 변화 예측에 널리 사용될 수 있는 상장 모델에 대해 간략히 소개하였다.