• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.663-670
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• 2018

The present study focused on the production, characterization, and in vitro prebiotic evaluation of an exopolysaccharides (EPS) from Bacillus sonorensis MJM60135 isolated from ganjang (fermented soy sauce). Strain MJM60135 showed the highest production ($8.4{\pm}0.8g/l$) of EPSs compared with other isolates that were screened for EPS production based on ropy culture morphology. Furthermore, MJM60135 was cultured in 5 L of medium and the EPS was extracted by ethanol precipitation. The emulsification activity of the EPS was higher in toluene than in o-xylene. Fourier transform infrared spectroscopy analysis showed the presence of hydroxyl and carboxyl groups and glycosidic linkages. The isolated EPS contained mannose and glucose, as observed by thin-layer chromatography analysis of the EPS hydrolysate. Lactic acid bacteria (LAB) and pathogenic E. coli K99 and Salmonella enterica serovar Typhimurium were tested for their growth utilizing the EPS from B. sonorensis MJM60135 as the sole carbon source for its possible use as a prebiotic. All the tested LAB exhibited growth in the EPS-supplied medium compared with glucose as carbon source, whereas the pathogenic strains did not grow in the EPS-supplied medium. These findings indicate that the EPS from B. sonorensis MJM60135 has potential application in the bioremediation of hydrocarbons and could also be used as a prebiotic.

• 미생물학회지
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• 제42권2호
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• pp.131-134
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• 2006

Clavicorona pyxidata DGUM 29005의 균사 생육을 위한 최적 배양조건 및 효소 활성을 조사하였다. 균사 생육을 위한 최적 온도 및 pH는 각각 $24^{\circ}C$ 및 5.0이었다. 사용된 복합배지 중 malt extract medium (MEM)에서 가장 좋은 균사 생육을 나타내었다. 최소배지로 Czapek-Dox 한천배지를 사용하고 탄소원으로 trehalose, mannitol, sucrose 및 maltose 첨가시 균사생육이 우수하였다. 전반적으로 무기질소원이 유기질소원 보다 균사 생육을 더 촉진하였으며, 무기질소원으로 calcium nitrate를 사용하였을 때 균사 생육이 가장 우수하였다. 인산원으로 $Na_2HPO_4$를 사용했을 때 균사생육이 촉진되었으며, 가장 우수한 비타민원은 p-aminobenzoic acid이었다. MEM 액체배지를 사용하여 $24^{\circ}C$에서 20일간 C. pyxidata DGUM 29005를 배양하여 균사외 분비효소 및 균사내 효소의 활성도를 측정한 결과, 균사외 분비 효소 중 laccase의 활성도가 다른 효소에 비해 높았으며, ${\alpha}$-amylase, chitinase, lipase 및 pretense의 활성도는 낮거나 없었다.

• 한국문헌정보학회지
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• 제18권
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• pp.99-127
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• 1990

This study attempts to verify the hypothesis that the interdisciplinary communication patterns may be different according to each disciplines. To put it concretely, it is intended to analyze and compare the subject distribution, the format, the age, the origin and the language of the documents of other disciplines cited in the journal articles according to each disciplines. To test the hypothesis philosophy, sociology and physics as the sample for the three disciplines, that is, humanities, social sciences, and natural sciences are sellected, and the documents cited in the journal articles published in 1966, 1971. 1976, 1981 and 1986 by the Korean Philosophical Association, the Korean Sociological Association and the Korean Physical Society are collected. And then the subject distribution, the format, the age, the origin, the language, and their use rate of the documents of other disciplines cited in the journal articles are investigated, analyzed and compared according to each disciplines. Some findings and conclusions made in the study are as follows. 1. The subject distribution of documents of other disciplines cited and its distribution ratio are different according to each disciplines, that is, humanities high, natural sciences low and social sciences medium. 2. The format and the use rate of documents of other disciplines cited are different according to each disciplines. In the three disciplines book and journal are more used than any format of documents in interdisciplinary communication while in case of the humanities and social sciences book is more used than journal, and in case of the natural sciences journal is more used than book in that communication. 3. The age and the use rate of the cited documents of other disciplines are different according to each disciplines. In case of the social sciences and natural sciences the documents of its last 20 years of publication are cited concentrately, and in case of the humanities the literature age is unconcerned. 4. The origin and the language of the cited documents of other disciplines, and its use rate are different according to each disciplines. In the humanities and natural sciences the documents published in foreign country are cited concentrately, and in the social sciences the home publication documents are more cited than the foreign. The documents of other disciplines in English language are most cited among the documents in any foreign languages in interdisciplinary communication. Putting the three disciplines in order of the use rate of the documents in English language, the natural sciences is high, the humanities medium, and the social sciences low. In the social sciences the use rate of the documents of other disciplines in Korean language is high while in the humanities and natural sciences slight.

• 한국환경보건학회지
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• 제27권2호
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• pp.60-66
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• 2001

Natural organic matters(NOMs) are found everywhere such as soil, surface and ground waters and consist of both humic and nonhumic components, and their heterogeneith makes each source unique. This study was carried to evaluate the removal characteristics of NOMs by mixing coagulants and the variation of apparent molecular weight distribution(AMWD) in coagulation process. Ratio of optimum coagulants dosage for removal of DOC and turbidity by mixing coagulants was 1.83 mM F $e^{3+}$/mM $Al^{3+}$. DOC removal increased at lower pH. The pH6 control focused on the removal of organic matters could reduce the amount of coagulant consumption by 2 to 3 times based on the pH8.5 of natural water. The dissolved organic matters in the natural water from the mid-stream of Han River were composed of the low molecular weight(LMW,<1 K) of 59.7%, and the medium and high molecular weight(M.HMW, 1~30 K) of 40.3%, respectively. At pH6, the DOC removal efficiencies of LMW(<1 K) and M.HMW(1~30 K) in coagulation process were 27~35%, 62~72%, respectively. The fraction smaller than 1 K was not eliminated to a noticeable degree, while the fraction of 1~30 K was relatively well removed. In conclustion, mixing coagulants were fairly effective in the removal of natural organic matter.r.

• 한국균학회지
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• 제25권3호통권82호
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• pp.226-232
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• 1997

경주시 남산으로부터 송이를 채집하여 균사를 분리하였다. 집락 및 균사의 형태, 균사의 독특한 송이향(1-octene-3-ol)을 기준으로 하여 Tricholoma matsutake DGUM 26001이라 명명하였다. T. matsutake DGUM 26001은 사용한 복합액체배지 중 yeast malt extract 및 Czapek-Dox 배지에서 가장 우수한 균사생육을 보여주었으며, nutrient glucose 배지, Macaya-Lizano 배지, 및 Tricholoma matsutake 배지(TMM)에서의 균사생육은 양호하였다. 세균 배양에 사용되는 colombia 배지, brain heart infusion 배지, Luria-Bertani glucose 배지 및 brucella 배지에서의 균사 생육은 매우 저조하였다. TMM 배지에 다양한 탄수화물을 탄소원으로 첨가하였을 때, 다당류의 starch, 이당류의 trehalose 및 maltose, 단당류의 sorbitol, xylitol 및 glucose를 사용하였을 때 균사생육이 양호하였다. Starch를 탄소원으로 하는 TMM 배지에서 30일간 균사를 배양하였을 경우, 8.85 g/L의 건조 균사중량을 얻을 수 있었다. 포도당을 탄소원으로 하는 TMM 액체배지에 coconut water 및 pyridoxine을 비타민으로 첨가하여 30일간 배양 후, 가장 우수한 균사 건조체를 얻을 수 있었으며 각각 8.65 및 8.32 g/L의 균사 건조량을 얻을 수 있었다.

• Clinical and Experimental Reproductive Medicine
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• 제21권1호
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• pp.99-110
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• 1994

One consequence of fertilization in mammals is an increased resistance of the zona pellucida (ZP) to proteases and various chemical reagents. This phenomenon has been called 'zona pellucida hardening' (ZPH), and it is generally accepted that it is caused by the secretory products of cortical granules released by the egg at fertilization. ZP of mouse oocytes maturing in vitro in a chemically defined medium becomes progressively more resistant to solubilization by chymotrypsin ("Spontaneous" ZP hardening). In the present study, it was aimed to find the specificity of spontaneous ZPH in relation to its possible relevance to the cortical reaction and the physiological block to polyspermy. When a maturation inhibitors, cAMP analog(dbcAMP) and phosphodiesterase inhibitor (IBMX) was added to culture medium, it prevent spontaneous ZPH of mouse oocyte during in vitro culture. Thus spontaneous ZPH requires GVBD, since it is prevented by those agents, which inhibit GVBD in vitro. However, culture for 3 hours in the presence of PMA(lOng/ml), a protein kinase C activator, resulted in ZPH without GVBD, thus suggesting that ZPH may be regulated independently apart from the event of GVBD. Pretreatment of mouse oocyte with FBS result in partially inhibitory effect on subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhibitory effect on the spontaneous ZPH, but subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhinbitory effect on the spontaneous ZPII, but had no inhibitory effect on PMA-induced ZPH. Treatment with a microfilament formation blocker(cytochalasin-B) at 1${\mu}g$/ml concentration, resulted in the excellent inhibitory effect on spontaneous ZPH. However cytochalasin-B did not inhibit PMA-induced ZPH. Thus this suggesting that spontaneuse ZPH had a different mechanism from PMA-induced ZPH.

• 자연과학논문집
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• 제5권2호
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• pp.3-11
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• 1992

ADP 농도를 증가시킴에 따라 미토콘드리아에 의한 Phosphocreatine의 생성속도는 포화 경향을 보이면서 증진되었다. 이 조건에서 Phosphocreatne 생성 속도를 측정하여 가해준 ADP에 대한 Km값을 구해본 결과 0. 0185 mM 임을 알았고, 이 Km값은 미토콘드리아의 Oxidative Phosphoryla-tion게와 연계되지 않은 (추출한) 미토콘드리아 Creatine Kinase의 ATP에 대한 Km 값인 0. 21mM보다 훨씬 낮음을 알 수 있었다. 이 외에도 ADP 존재하에 Oxidative Phosphorylation에 의한 ATP 생성에 대한 Creatine Kinase의 활성의 영향을 살펴본 결과 이 조건에서 Phosphocreatine은 반응시간에 정비례하게 생성 되었으나, 생성된 ATP는 반응시간에 무관함을 보였다. 또한 Oxidative Phosphorylation에 의해 미토콘드리아 외부 Respiration 용액 내에 이 ATP가 축적되는 속도도 미토콘드리아 Creatine Kinase의 Phosphocreatine 생성과 무관함을 알수 있었다. 이상의 결과들은 Mitochondrial Creatine Kinase가 Oxidative Phosphorylation계와 기능적으로 밀접하게 연계되어 ATP가 아닌 Phophocreatine이 에너지 전달 물질로 직접 이용될 가능성을 시사해준다.

• Journal of Plant Biotechnology
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• 제43권2호
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• pp.240-247
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• 2016

In this study, routinely used transformation method, which includes transferring explants onto co-cultivation medium after inoculating them with bacterial solution for a while, was compared with 3 different inoculation methods. In every 3 methods, hypocotyl explants excised from 7-day-old sterile flax seedlings having cotyledon leaves and no root system dried under air flow in sterile cabin for 35 min were inoculated with different volumes of bacterial solution at different inoculation periods. GV2260 line of Agrobacterium tumefaciens having 'pBIN 19' plasmid containing npt II (neomycin phosphotransferase II) gene and GUS reporter gene was used in transformation studies. After inoculation, hypocotyl segments of seedlings (0.5 cm in length) - were excised and left to co-cultivation for 2 days. Then, explants were transferred to regeneration medium supplemented with different antibiotics. The presence of npt-II and GUS genes in transformants was confirmed by PCR and GUS analysis. The highest results in all characters examined in all cultivars were obtained from the 2 inoculation method in which hypocotyls excised from seedlings inoculated with $500{\mu}l$ of bacterial solution after drying in sterile cabin for 35 min were used.

• Structural Engineering and Mechanics
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• 제65권4호
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• pp.491-504
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• 2018

Because of sandwich structures with low weight and high stiffness have much usage in various industries such as civil and aerospace engineering, in this article, buckling and free vibration analyses of coupled micro composite sandwich plates are investigated based on sinusoidal shear deformation (SSDT) and most general strain gradient theories (MGSGT). It is assumed that the sandwich structure rested on an orthotropic elastic foundation and make of four composite face sheets with temperature-dependent material properties that they reinforced by carbon and boron nitride nanotubes and two flexible transversely orthotropic cores. Mathematical formulation is presented using Hamilton's principle and governing equations of motions are derived based on energy approach and applying variation method for simply supported edges under electro-magneto-thermo-mechanical, axial buckling and pre-stresses loadings. In order to predict the effects of various parameters such as material length scale parameter, length to width ratio, length to thickness ratio, thickness of face sheets to core thickness ratio, nanotubes volume fraction, pre-stress load and orthotropic elastic medium on the natural frequencies and critical buckling load of double-bonded micro composite sandwich plates. It is found that orthotropic elastic medium has a special role on the system stability and increasing Winkler and Pasternak constants lead to enhance the natural frequency and critical buckling load of micro plates, while decrease natural frequency and critical buckling load with increasing temperature changes. Also, it is showed that pre-stresses due to help the axial buckling load causes that delay the buckling phenomenon. Moreover, it is concluded that the sandwich structures with orthotropic cores have high stiffness, but because they are not economical, thus it is necessary the sandwich plates reinforce by carbon or boron nitride nanotubes specially, because these nanotubes have important thermal and mechanical properties in comparison of the other reinforcement.

• 대한기계학회논문집
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• 제16권5호
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• pp.952-964
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• 1992

본 연구에서는 2차원 정사각형 밀폐공간내에 열복사를 흡수, 방사 및 비등방 산란하는 매질이 존재할 때 자연대류와 복사의 상호작용을 선형 비등방 산란을 가정 하고 복사열전달의 계산시 P-N 근사법을 이용하여 해석하였다. 수치계산을 통하여 Planck 수, 산란알베도, 광학두께, 벽방사율 및 비등방 산란이 유동 및 온도 특성 그리고 열전달에 미치는 영향을 조사하였다.