차 향기의 생성 메커니즘

조미자(MiJa Cho),조기정(Gijeong Cho),최현숙(HyunSook Choi),최두복(Dubok, Choi),조기안(KiAn Cho),조훈(Hoon Cho) 한국생물공학회 2016 KSBB Journal Vol.31 No.2

Tea is an aqueous infusion of dried leaves of the plant Camellia sinensis L. and is the second most widely consumed beverage around the world after water. Aroma compounds of tea differ largely depending on the manufacturing process, even from the same categories of different origins. The flavor of tea can be divided into two categories: taste (non-volatile compounds) and aroma (volatile compounds). In the present study, we review the formation mechanism of main aromas generated from carotenoids, lipids, glycosides as precursors, and Maillard reaction during the tea manufacturing process, with biological and chemical mechanisms.

Extraction and Antioxidant Activity of Polysaccharides Produced from Liquid Culture of Pleurotus Sajor-Caju PSC-14

( Kian Cho ),( Hayoung Koh ),( Dubok Choi ) 조선대학교 공학기술연구원 2015 공학기술논문지 Vol.8 No.3

This research investigated extraction and antioxidant activity of polysaccharides produced from liquid culture of Pleurotus sajor-caju PSC-14. When the ratio of water to sample was increased from 10:1 to 40:1 (mL/g), the polysaccharides extraction yields were increased from 47.2 to 100%. On the other hand, when the ratio increased from 50:1 to 60:1, the yields of polysaccharides extraction were decreased from 80.2% to 62.3%. Extraction yields of polysaccharides were increased with extraction temperature. Especially, when the extraction temperature was increased from 40 to 80 oC, extraction yields of polysaccharides were increased from 41.2 % to 82.6%. On the other hand, at the extraction temperature of 100 oC, there was a little decrease in polysaccharides yield. Maximum extraction yield of polysaccharides was obtained at the extraction temperature of 90 oC. To investigate effect of polysaccharides concentration on antioxidant activity, DPPH scavenging activities were measured. When the polysaccharides concentration was 15.0 mg/mL, the maximum DPPH radical scavenging activity was obtained, 69.25%.

시스템 오브 시스템즈의 런타임 검증 속성 명세 유형 분석 및 적용

조은호(Eunho Cho),박수민(Sumin Park),Lingjun Liu,Chua Kiat Kian Anthony,배두환(Doo-Hwan Bae) 한국정보과학회 2020 한국정보과학회 학술발표논문집 Vol.2020 No.12

Effect of Carbon Source Consumption Rate on Lincomycin Production from Streptomyces lincolnensis

( Du Bok Choi ),( Kian Cho ) 한국미생물생명공학회 2004 Journal of microbiology and biotechnology Vol.14 No.3

NEW TECHNIQUES WITH AN APPLICATION OF ZEOLITES AND CLAYS TO REMEDIATION WORKS FOR POLLUTED SOILS AND CLAY BARRIERS

( Hideo Minato ),( Tatsuo Morimoto ),( Kian Cho ),( Jaewan Pak ) 한국폐기물자원순환학회 2002 APLAS Vol.2002 No.1

Contaminated soil and water by heavy metals, arsenic and other toxic pollutions are usually created under human activities. An effective remediation technique for the polluted land has been developed using of natural materials, such as zeolite, volcanic loam (weathered volcanic ash), and dolomite, instead of artificial materials, such as chemicals, organic compounds, concrete, and etc. The mechanism of cation exchange and/or adsorption conducts those hazardous heavy metals and arsenic in the polluted soil to be fixed and settled into newly crystallized hydrous alkaline and alkaline earth aluminosilicates as minor elements. The technique to use natural materials that trap and fix hazardous metals is called as Sealing Soil Technique. This is applicable not only for the remediation for polluted soil but also for materials of clay barrier to be used as a wall and/or bed of final waste disposal site of urban area. One of the immense advantages is to prevent secondary pollution derived from seepage that contains decomposed chemical substances and organic matters, used for the remediation treatment and barrier material. Using the similar technique we have develop effective procedure in low cost using a prescribed mixture of mainly natural material, zeolite, clay, dolomite and others under the name of TRP for remediation of contaminated water with heavy metals and arsenic from various sources. It includes a process to neutralize, oxidize, precipitate and filtrate out the precipitates of metals and arsenic under severe pH control.

A Study on Chitinase Production from Bacillus licheniformis H-89

( On You Cboi ),( Kian Cho ),( Shiru Jia ),( Young Cheol Chang ) 조선대학교 공학기술연구원 2012 공학기술논문지 Vol.5 No.3

This research was to investigate optimal condition for effective chitinase production from Bacillus licheniformis H-89 by changes using working volume, carbon source, nitrogen source, culture temperature, and initial pH of medium at flask for 48 hr. The chitinase production was appropriate when the working volume was 50 mL/500 mL of flask. Among various carbon sources, glucose was best carbon source. Especially, 20 or 25 g/L of glucose was optimum concentration for effective chitinase production. Among various nitrogen sources, yeast extract was also best one for chitinase production. The optimal pH and optimal temperature of chitinase production ranged of 6.0 to 7.0 and 35℃. These results suggest that all these optimal conditions can be applied for effective chitinase production from Bacillus licheniformis H-89.

Cellulose Production from Gluconobacter oxydans TQ-B2

최두복,차월석,Shiru Jia,KiAn Cho,Mitsuyasu Okabe,Hongyu Ou,Guibing Chen 한국생물공학회 2004 Biotechnology and Bioprocess Engineering Vol.9 No.3

Gluconobacter oxydans that produces the cellulose was isolated. In order to confirm the chemical features of cellulose, various spectrophtometeric analysis were carried out using electron microscopy, X-ray diffractogram, and CP/MAS 13C NMR. The purified cellulose was found to be identical to that of Acetobacter xylinum. For effective production of cellulose, the various carbon and nitrogen sources, mixture of calcium and magnesium ions, and biotin concentration were investigated in flask cultures. Among the various carbon sources, glucose and sucrose were found to be best for the production of cellulose, with maximum concentration of 2.41 g/L obtained when a mixture of 10 g/L of each glucose and sucrose were used. With regard to the nitrogen sources, when 20 g/L of yeast extract was used, the maximum concentration of bacterial cellulose was reached. The concentration of cellulose was increased with mixture of 2 mM of each Ca2+ and Mg2+. The optimum biotin concentration for the production of cellulose was in the range of 15 to 20 mg/L. At higher biotin concentration (25~35 mg/L), the bacterial cellulose production was lower.

Effect of Mixing Ratio of Biodiesel on Breakup Characteristics of a Single Droplet

( Yop Kim Sa ),( Sung Wook Park ),( Kian Sung ),( Haeng Mook Cho ),( Chang Sik Lee ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-

In this paper, the breakup characteristics of a single droplet were analyzed as a function of mixing ratio of bioidesel. In order to investigate the effects of high surface tension and viscosity of biodiesel on the breakup mechanism of single droplet, the experiments were performed at various mixing ratios of biodiesels. In addition, the physical properties such as density, kinematic viscosity and surface tension of the biodiesel blended fuels were measured to study the relations between the non-dimensional numbers such as Weber number and Reynolds number, and the breakup mechanism. The experimental apparatus consisted of a droplet generation system, an air flow nozzle, a light source, a long distance microscope and a CCD camera. In the first stage breakup region, the droplet deformation rate was measured in order to reveal out the effect of high surface tension and kinematic viscosity on the deformation of a single droplet. The results of this experiment showed that the higher surface tension and viscosity of biodiesel prevent the disintegration of liquid droplet. Also the breakup mechanism is transited at higher relative velocity as the mixing ratio is increased.

Production of α-amylase from Bacillus megaterium in the Air Lift Bioreactor Using Corn Starch as Sole Carbon Source

( On You Choi ),( Shiru Jia ),( Kian Cho ),( Young Cheol Chang ) 조선대학교 공학기술연구원 2012 공학기술논문지 Vol.5 No.2

This research was to investigate the effective production of α-amylase from a culture of Bacillus megaterium H-829 using corn starch as the carbon source and corn steep liquor (CSL) as the nitrogen source in air-lift bioreactor. α-amylase production was increased from 10.5 to 49.1 DUN/mL when corn starch concentration was increased from 5 to 15 g/L. However, when corn starch concentration was increased from 20 to 30 g/L, the enzyme production was decreased from 44.7 to 28.5 DUN/mL. In the case of CSL concentrations, while CSL concentration was increased from 2.5 to 5.0 g/L the α-amylase production was increased from 48.9 to 58.6 DUN/mL. However, it was decreased from 55.4 to 25.4 DU /mL when CSL concentration was increased from 7.5 to 15.0 g/L. The cell concentration was decreased with the increase of acetic acid concentration produced. Especially, when acetic acid concentration was over 1.5 mg/L, it was sharply decreased. In order to compare the effects of corn starch and glucose on the production of amylase in the air-lift bioreactor, batch cultures were carried out in a 5 L air-lift bioreactor for 48 hr using production media containing corn starch 15 g/L and CSL 5 g/L respectively. When corn starch was used, the maximum α-amylase production after 36 hr of culture was 40 DUN/mL, which was similar to that of the glucose medium. These results indicate that corn starch and CSL can be useful for α-amylase production from Bacillus megaterium H-829 in air-lift bioreactor.

Clinical Characteristics of Post-COVID-19 Persistent Cough in the Omicron Era

Kang Yu Ri,Huh Jin-Young,Oh Ji-Yoon,Lee Ji-Hyang,Lee Daegeun,Kwon Hyouk-Soo,Kim Tae-Bum,Choi Jae Chol,Cho You Sook,Chung Kian Fan,Park So-Young,Song Woo-Jung 대한천식알레르기학회 2023 Allergy, Asthma & Immunology Research Vol.15 No.3

Cough is one of the most common symptoms of acute coronavirus disease 2019, but cough may persist for weeks or months. This study aimed to examine the clinical characteristics of patients with post-coronavirus disease (COVID) persistent cough in the Omicron era. We conducted a pooled analysis comparing 3 different groups: 1) a prospective cohort of post-COVID cough (> 3 weeks; n = 55), 2) a retrospective cohort of post-COVID cough (> 3 weeks; n = 66), and 3) a prospective cohort of non-COVID chronic cough (CC) (> 8 weeks; n = 100). Cough and health status was assessed using patient-reported outcomes (PROs). Outcomes, including PROs and systemic symptoms, were longitudinally evaluated in the prospective post-COVID cough registry participants receiving usual care. A total of 121 patients with post-COVID cough and 100 with non-COVID CC were studied. Baseline cough-specific PRO scores did not significantly differ between post-COVID cough and non-COVID CC groups. There were no significant differences in chest imaging abnormality or lung function between groups. However, the proportions of patients with fractional exhaled nitric oxide (FeNO) ≥ 25 ppb were 44.7% in those with post-COVID cough and 22.7% in those with non-COVID CC, which were significantly different. In longitudinal assessment of the post-COVID registry (n = 43), cough-specific PROs, such as cough severity or Leicester Cough Questionnaire (LCQ) scores, significantly improved between visits 1 and 2 (visit interval: median 35 [interquartile range, IQR: 23–58] days). In the LCQ score, 83.3% of the patients showed improvement (change ≥ +1.3), but 7.1% had worsened (≤ −1.3). The number of systemic symptoms was median 4 (IQR: 2–7) at visit 1 but decreased to median 2 (IQR: 0–4) at visit 2. In summary, post-COVID persistent cough was similar in overall clinical characteristics to CC. Current cough guideline-based approaches may be effective in most patients with post-COVID cough. Measurement of FeNO levels may also be useful for cough management.