• Korean Journal of Microbiology
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• v.51 no.3
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• pp.263-270
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• 2015

A bacterial strain producing extracellular mannanases was isolated from soil of chestnut tree farm located in Gongju city of Korea by enrichment culture using Avicel as a carbon source. 16S rDNA sequence of the isolate YB-43 was highly homologous to those of genus Cellulosimicrobium strains with sequence similarities of above 99.6%. Mannanase productivity was significantly increased when the Cellulosimicrobium sp. YB-43 was grown in the presence of locust bean gum (LBG) or konjac. The mannanases were partially purified to be mannanase A (ManA) and mannanase C (ManC) by DEAE-Sepharose column and Q-Sepharose column chromatography from the culture filtrate of Cellulosimicrobium sp. YB-43 grown in LB medium supplemented with 0.7% LBG for 24 h. The partially purified ManA showed the highest activity at $55^{\circ}C$ and pH 6.5, while ManC activity was optimal at $65^{\circ}C$ and pH 7.5. ManA was stable up to $40^{\circ}C$ for 1 h, but ManC activity decreased significantly even after 1 h at $20^{\circ}C$. ManA and ManC showed difference from each other according to their substrate specificities and predominant products resulting from the mannanase hydrolysis for mannooligosaccharides. As a result, Cellulosimicrobium sp. YB-43 was found to produce two different kinds of mannanases.

• Journal of Life Science
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• v.22 no.2
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• pp.167-176
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• 2012

Three protease-producing halophilic bacteria were isolated from fermenting anchovy. Isolated FAM 10, FAM 114, and FAM 115 were found to grow optimally at salt concentrations of 2-4%, 10%, and 6%, respectively, and could grow in salinity of up to 18-22%. The salinity conditions for optimum protease production were 6% in FAM 10 and 10% in FAM 114 and FAM 115. The protease activity of FAM 10 was gradually inhibited by the addition of NaCl up to 10%, and was not evident at 14%, whereas FAM 114 and FAM 115 displayed protease activity at 14% NaCl and could not be measured at 18%. These results demonstrated that the three isolated strains belong to protease-producing, moderately halophilic bacteria. Strain FAM 10, FAM 114, and FAM 115 were identified as Salinivibrio sp., Halobacillus sp., and Halobacillus sp. respectively, based on comparative analyses of the 16S rRNA gene and the 16S-23S intergenic space sequence (IGS), biochemical testing, and Gram staining. Salinivibrio sp. FAM 10 had two 16S rDNAs containing different sequences at position 191 and four IGSs that harbored no tRNA gene and tRNA genes for isoleucine, alanine, glutamate, lysine, and/or valine. Halobacillus sp. FAM 114 and FAM 115 had completely identical 16S rRNA gene sequences and showed 99% identity to the sequences of various Halobacillus strains. The three IGSs found in the genome of both strains displayed 99% sequence identity with Halobacillus aidingensis and Halobacillus sp. JM-Hb, and had $IGS^0$ with no tRNA gene and $IGS^{IA}$ with tRNA genes for isoleucine and alanine.

• Journal of Mushroom
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• v.10 no.2
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• pp.74-82
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• 2012

Sixty strains of Pleurotus ostreatus, white-rot fungi, were screened for production ability of their lignocellulolytic enzymes to selectively wood degradation. That results were shown that all of screened strains were produced lignocellulolytic enzymes on 2nd screening liquid culture medium. However, cellulase activity of selected six strains of P. ostreatus was low in avicel-yeast-peptone liquid culture medium. In the case of xylan degrading enzyme, No. 6 and No. 38 strains produced a xylanase(above 1.0U/ml) and a 1,4-${\beta}$-xylosidase (above 0.15 U/ml). Examination of the ligninolytic enzyme profiles of selected thirteen strains of the P. ostreatus, in the presence of Remazol Brilliant Blue R(RBBR), were observed that laccase(Lac) activity were earlier reached maximum level(0.8-2.0 U/ml) and then Mn-dependent peroxidase (MnP) were reached maximum level(0.5-1.5 U/ml) in glucose-yeast-peptone(GYP) medium. On the other hand, activity of lignin peroxidase(LiP) was not detected in this medium. I selected the No. 42 strain of P. ostreatus produced high levels of Mn-dependent peroxidase and laccase based on the screening method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.13-23
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• 2017

This study deals with the strengthening effect and behavioral characteristics of square concrete column wrapped with carbon FRP sheet. The increase in axial compression capacity comes from the confinement effect of wrapped CFRP sheet. Because of the shape of square concrete column, the confinement effect is smaller than that in circular column. For the experimental program, four parameters including the number of sheet, the size of column specimen, the aspect ratio, the corner rounding, and the transformation in shape from square to circular were selected to examine the strengthening effect and behavioral characteristics for each parameter. Experimental program comprised fifty five square concrete column specimens for different eleven types. The compression test results confirmed that the strengthening effect can be increased by the confinement of wrapped and bonded CFRP sheet. However, the confining effect was decreased with the increase of square column size. The other hand, the ductility in square concrete column greatly increased due to caging effect of CFRP sheet. The transformation in shape from square to circular considerably increased both the compressive strength and the ductility of the concrete column wrapped with CFRP sheet. In addition, using test results and existing studies, accuracy and reliability of the existing strength models for CFRP-confined square concrete are verified.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.134-140
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• 2017

In this study, the flexural behavior of high strength concrete members with different curing condition of 90 MPa of compressive strength was investigated. Experimental parameters included normal and low temperature curing conditions, tensile steel amount and concrete compressive strength. 8 beam members were fabricated and flexural tests were carried out. Crack spacing, load-deflection relation, load-strain relation and ductility index were determined. Experimental results show that as the amount of rebar increases, the number of cracks increases and the crack spacing decreases. The higher the concrete strength, the smaller the number of cracks, but the effect is significantly smaller than the amount of rebar. As a result of comparison with the proposed average crack spacing in the design criteria, the experimental results are slightly larger than the results of the proposed formula, but the proposed formula does not reflect the concrete strength and curing conditions. The ductility index of normal temperature cured members was 3.36~6.74 and the ductility index of low temperature cured members was 1.51~2.82. The behavior of low temperature cured members was found to be lower than that of normal temperature cured members. As a result of comparing the ductility index with the existing studies similar to the experimental members, the ductility index of the high strength concrete member was larger than the ductility index of the ordinary strength concrete of the previous study. Further research is needed to understand more specific results.

• Korean Journal of Occupational Health Nursing
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• v.14 no.2
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• pp.93-107
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• 2005

Purpose: The purpose of this study is to identify the trends of studies on work-related musculoskeletal disorder and to suggest the direction of future research. Method: 144 research thesis for a degree on work-related musculoskeletal disorder were systematic reviewed and published from Jan. 1990 to Mar. 2005. The analyzed using descriptive statistics, an actual number, percentage. Result: As its result the work-related musculoskeletal disorder research which is announced from domestic the doctorate dissertation at the 2004 year 42 the most many 144 dissertation middle most to be 129 in master degree dissertation was 15 in Ph D degree. Dissertation contents character the contents against the result relation that it analyzes especially and a condition and an obstacle was many most at 84. Research plan in most description investigation research 121 the dissertation field to be the especially public health (hygiene, industry and environment) at this 57 most many research object person distribution manufacturing industry in the research object one dissertation was many most at the 40. The tools which are used in each measurement in the question tool which it uses most the question price of land which uses the condition investigation ticket which it made from the NIOSH and the ANSI most many 33, the hazard which analyzes a work attitude in the tool which it uses the RULA was many most at 14. In the stress test tool social psychological healthy measurement PWI (Psychological Wellbeing Index) the dissertation which uses the Job Strain of the Karasek Model to be many most at 19 PWI (Psychological Wellbeing Index) 7 easy use. Work-related musculoskeletal disorder measurement hazard in physiological index and the machinery and tools which it uses there were 9 researches to use an electromyogram most plentifully. With the effect goes to a work-related musculoskeletal disorder they are 33 where the age is many most from general quality. From healthy act with the relation of smoking the year to be many from 16 dissertations. Work of the corpse an attitude (the attitude which is inappropriate) with 5 and the work market the work burglar is many most at 9, the society-support of 36 where the stress is many psychologically most, the stress and service also the most many duty discretion (authority and autonomy) is 6 at the duty demand boat song 9. The service career to be many is 22 of extraordinarily with relation of service. Conclusion: It is recommended the research which it sees being limited in only domestic thesis for a degree the international comparative study to become accomplished. It comes to think with the fact that it will be necessary to make the protocol which it conforms in the civil official guide the test researches for the protocol or arbitration program which is standardized are necessary. Prevention and the civil official of work relation bones and sinews standing total disease hazard scientific base one program is necessary with base.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.52-59
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• 2003

Tests of concrete CLWL-DCB specimens had been conducted with displacement-controlled dynamic loading. The crack velocities for 381mm crack extension were 0.80 mm/sec ~ 215m/sec. The external work and the kinetic and strain energies were derived from the measured external load and load-point displacement. The fracture resistance of a running crack was calculated from the fitted curves of the fracture energy required for the tests. The standard error of the fracture energy was less than 3.2%. The increasing rate of the fracture resistance for 28 mm initial crack extension or micro-cracking was relatively small, and then the slope of the fracture resistance increased to the maximum value at 90∼145 mm crack extension depending on crack velocity. The maximum fracture resistance remained for 185 mm crack extension, and then the faster crack velocity showed the faster decreasing rate of the maximum fracture resistance. The maximum fracture resistance increased proportionally to the logarithm of the crack velocity from 142 N/m to 217 N/m when the crack velocity was faster than 0.273 m/sec. The maximum fracture resistance of the fastest tests was similar to the average fracture energy density of 215 N/m. To measure the fracture resistance of concrete, the stable crack extension should be larger than 90∼145 mm depending on crack velocity.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.575-583
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• 2010

This research investigated the influence of the number of twist on single fiber pullout behavior of Twisted steel (T-) fiber and tensile behavior of high performance cementitious composites reinforced with the (T-) fibers (HPFRCC). Micromechanical pullout model for T- fibers has been applied to analytically investigate the influence of various fiber parameters including the number of twist on single fiber pullout behavior; and, to optimize the number of twist to generate larger pullout energy during fiber pullout without fiber breakage. In addition, an experimental program including single fiber pullout and tensile tests has been performed to investigate the influence of twist ratio experimentally. Two types of T- fiber with different twisted ratios, T(L)- fiber (6ribs/30 mm) and T(H)- fiber (18ribs/30 mm), were tested. T(L)- fiber produced higher equivalent bond strength (larger pullout energy) although T(H)- fiber produced higher pullout stress during pullout since T(H)- fiber showed fiber breakage during pullout. Tensile test results confirmed that T(L)- fiber in high strength mortar generates better tensile performance of HPFRCC, e.g., load carrying capacity, strain capacity and multiple micro-cracking behavior.

• The Journal of Korean Academy of Prosthodontics
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• v.17 no.1
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• pp.47-59
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• 1979

In order to study the morphologic changes of the unfixed odontoblasts suspended in phenol solution of several different concentrations, the author carried out the extraction of lower incisor of S-D strain rats to collect the odontoblasts, and the cells obtained were suspended immediately in saline solution. After observing the odontoblasts in fresh state, the saline solution was substituted with 0.125%, 0.25% 0.5%, 1% and 2% diluted phenol solutions. The morphologic changes were examined with phase contrast microscope at intervals of 10, 30, and 60 minutes. The results were as follows: 1. In saline solution the odontoblast showed cytoplasmic swelling, slender cytoplasmic process, thick rim nuclear membrane with increased dark contrast, and prominent nucleoli and chromatin granules with lapse of time intervals. In accordance with time intervals, blisters appeared in the supranuclear zone and increased its size and moved outward of the cytoplasmic membrane resulting detachment from the cell membrane. The phase dark cytoplasmic granules were increased in its dark contrast and in its size. 2. In 0.125% and 0.25% phenol solution, the odontoblasts and its nucleus shrunk immeidately and its contrast of cellular components was increased. With the lapse of time, the phase-dark granules in cytoplasm were aggregated, and several blisters were formed in and out of the cells. The outline of cytoplasmic membrane was also obscured. 3. In 0.5% phenol solution, the necleus shrunk at once, but soon after it revealed karyolysis accompanying dark contrast of neclear components such as nuclear membrane, nucleoli, and chromatin granules. On the contrary, the cytoplasmic granules showed aggregation and increased dark contrast, small and large blisters were formed in and out of the odontblasts and the outline of cytoplasmic membrane became obscured. 4. In 1% phenol solution, it showed shrinkage of odontblasts and its nuclei with thick rim nuclear membrane, aggregation of chromatin granules and occasional karyorrhexis. The dark contrast of cytoplasmic granules was increased and aggregated each other. But the blister formation could not be found. 5. In 2% phenol solution, it showed the shrinkage of odontoblasts and pyknotic nuclei with increased dark contrast of nucleoli and chromatin granules. The number of cytoplasmic granules was decreased by aggregation. But the blister formation could not be found as in 1% phenol solution.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.153-170
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• 1989

Recently, frequently using hyperbaric oxygen therapy is known for its effectiveness on the healing of problem wounds such as osteomyelitis, osteoradionecrosis and gas gangrenous wound etc. The main objectives of this study was to determine the best protocol of its application of hyperbaric oxygen therapy. Author used 238 rats (Sprague-Dawley strain) deviding into 2 Groups, experimental I group for skin and experimental II group for palatal mucosal ischemic wounds, and observed its effects by microscopically. The obtained results summarized as follows; 1. Severe infiltration of inflammatory cells was observed in initial stages of both control and experimental I group. The infiltration showed decreasing tendency at 5th day of experimental D, E, F group while at 8th day in control group In d, f of experimental II group showed decreasing tendency at 8th experimental day while at 12th day in control group. 2. Macrophages appeared at 2nd day in D of experimental I group while at 6th day in control group. In d, f of experimental II group appeared at 6th day while at 10th day in control group. 3. As to the proliferation of capillary blood vessels showed at 3-4 day in most of experimental I group severely while at 8th day in control group. In experimental II group, it was at 8th day and 12th day respectively. 4. The proliferation of fibroblasts showed rather rapider in experimental I group, at 4-6th day, while at 8th day in control group. In experimental II group, it was at 8th day and 12th day respectively. 5. As to the collagen formations, it was at 4th day in experimental I group while at 8th day in control group. In experimental II group, it was at 6th day and 10th day respectively. 6. 5 rats (2.0 %) in E group and 8 rats (3.4 %) in f group showed oxygen toxic reaction, such as unstable attitude and tremor, during the experiments. This hyperbaric oxygen animal experiments disclosed excellent effects on the ischemic wound healing and it is thought to be the best protocol of its application was on D group (2.5 ATM. and 2 hrs, exposure).