• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1248-1254
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• 2007

The secretory overexpression of Clostridium thermocellum endoglucanase A gene (celA) was examined in Saccharomyces cerevisiae using Kluyveromyces marxianus exoinulinase (INU1) signal sequence and GAL10 promoter. The two plasmids, pYEG-CT1 with its own signal sequence, and pYInu-CT1 with INU1 signal sequence were introduced to S. cerevisiae SEY2102 and S. cerevisiae 2805 host strains, respectively, and then each transformant was selected on the synthetic defined media lacking uracil. The expression level and secretion efficiency of endoglucanase A was increased by $18{\sim}22%$ and 11%, respectively, by INU1 signal sequence over celA signal sequence. By considering the high level of expression (361 unit/I), plasmid stability (89%), and secretion efficiency (70%), S. cerevisiae 2805 harboring plasmid pYInu-CT1 was selected as the opti-mal host vector system for the production of cellulose-degrading enzyme and recombinant yeast probiotic. The total expression and secretion efficiency of endoglucanase A was 418 unit/l and 73%, respectively, in the batch fermentation of S. cerevisiae 2805/pYlnu-CT1 on galactose medium. The mo-lecular weight of secreted endoglucanase A was found to be greater than 100 kDa, presumably due to the N-linked glycosylation.

• KSBB Journal
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• v.18 no.4
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• pp.249-254
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• 2003

Experiments were carried out to select an industrial nitrogen source and optimize erythritol production by Candida magnoliae in fed-batch culture. Among the industrial nitrogen sources tested, light steep water (LSW) was found to be the best nitrogen source for producing erythritol, based on erythritol yield and raw material price. The maximum erythritol concentration obtained a 131.6 g/L, with a 52.6％ yield and 0.52 g/L-hr productivity from a 250 g/L glucose and 43.3 mL/L LSW in batch culture. Two-stage fed-batch culture was chosen to improve the volumetric productivity and the yield of erythritol. High cell density culture in cell growth stage was achieved by batch type culture containing 100 g/L glucose and 500 mL/L LSW. The cell concentration was 71.0 g/L after 23 hours of culture. Erythritol productivity was decreased by increasing glucose concentration in the production stage. But 37.3％ of the maximum erythritol yield was obtained with 185.5 g/L of erythritol and 1.66 g/L-hr of productivity when 820 g of glucose powder was directly added to a concentration of 450 g/L glucose in production stage.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.470-476
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• 2011

Introduction: The incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ) has increased gradually in patients who have undergone surgical treatment for osteomyelitis. In this study, a retrospective analysis of BRONJ patients was carried out using the data of osteomyelitis patients treated surgically. Materials and Methods: Osteomyelitis patients, who underwent curettage, sequestrectomy, saucerization or decortications, and partial mandibulectomy at Seoul National University Dental Hospital from 2004 to 2010 were enrolled in this study. The patients were classified and categorized into two groups based on the surgical records and progress notes. One group comprised of patients with osteomyelitis and osteoporosis, and the other group included patients with osteomyelitis only. The epidemiological data of the BRONJ patients was analyzed to identify any trend in the incidence of BRONJ in osteomyelitis patients. Results: Among 200 patients who underwent surgical intervention for osteomyelitis, 64 (32.0%) were identified as having osteoporosis as the underlying disease. In these 64 patients, more than 81.3% had been prescribed bisphosphonates. Females were far more affected by BRONJ than males. The incidence of BRONJ also increased with age. The posterior part of the mandible was affected more frequently by BRONJ. Conclusion: Although the availability of potent antibiotics and increased oral hygiene care can reduce the overall incidence of osteomyelitis, BRONJ can increase the total incidence. To prevent BRONJ, it is recommended that an oral examination be performed before prescribing bisphosphonates. Moreover, the patients should be educated about the potential risks of dental procedures that might be causal factors for BRONJ. Furthermore, patient swho take bisphosphonates for the treatment of osteoporosis should undergo periodic follow up oral examinations to prevent BRONJ.

• KSBB Journal
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• v.15 no.2
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• pp.113-119
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• 2000

In order to produce xylitol with high yield, experiments were carried out to develope xylitol dehydrogenase (XDH) defective m mutant from Pichia stipitis and to investigate the xylit이 fermentation characteristics of mutant strain. After treatment of P s stipitis with EMS, mutant PXM-4 was selected based on the XDH activity and xylitol production capability. Among the tested c cosubstrates, galactose was selected as an adequate cosubstrate on xyl뻐I production of mutant PXM-4. With the increase of galactose concentration, xylitol production was decreased because the transport of xylose into cell was inhibited by g galactose. The optimal concentration of galactose for the production of xylitol using 20 g/L xylose was 20 g/L. Under this c condition, maximum concentration of xylitol and yield were 14.4 g/L and 97%, respectively. In order to prevent the inhibitory e effect of xylose transport by galactose, galactose was fed with low concentration and the concentration of xylitol produced w was increased up to 25 g/L. In the fermentation of corn cob hydrolyzate by mutant PXM-4, xylose was completely converted t to xylit이 with a 100% yield in 4 days culture.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.170-175
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• 2001

In order to produce xylitol with high yield, experiments were carried out to develope xylitol dehydrogenase(XDH) defective mutant from P. stipitis and to investigate the xylitol fermentation characteristics of mutant strain. After treatment of P. stipitis with EMS, mutant PXM-4 was selected based on te XDH activity and xylitol production capability. Among the tested cosubstrates, galactose was selected as an adequate cosub-strate on xylitol production of mutant PXM-4. But with the increase in the concentration of galactose in the medium, xylitol production was decreased because the transport of xylose into cell was inhibited by galactose. The optimal concentration of galactose for the production of xylitol using 20 g/ι xylose was 20 g/ι Under this condition, maximum concentration of xylitol and yield were 14.4 g/ι and 97%, respectively. In order to prevent the inhibitory effect of xylose transport by galactose, galactose was fed with low concentration and the concentration of xylitol produced was increased up to 25 g/ι.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.110-117
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• 1998

A packed-bed reactor with immobilized transglucosidase (TG) was operated to test the possibility of continuous production of isomaltooligosaccharides (IMO) and the effect of concentration and feed rate of substrate solution on the production pattern as well as operational stability The pattern of formation of IMO was the same to the one of soluble TG. The concentrations of glucose and isomaltose produced by the packed-bed reactor were gradually decreased as the flow rates were increased regardless of the concentrations and kinds of maltose solution as substrate. Isomaltotriose showed the same tendency except 10% maltose solution. But the concentration of panose was increased and then decreased as the flow rates were increased. The maximum yield of IMO was 52.1% when 10% (w/v) solution was fed to the reactor at 2 mL./min feed rate. When each 20% and 30% (w/v) solution was respectively used at $0.5{\sim}1.0\;mL/min$, the maximum yield were $39.0{\sim}38.0%\;and\;12.1{\sim}14.2%$. The maximum yield was 36.3% at $0.5{\sim}1.0\;mL/min$ when a commercial maltose product containing 20% maltose was used. The reactor was stably operated at $55^{\circ}C$. 85% and 65% of initial activity was maintained for 144 hours and 288 hours of operation, respectively. A reactor analysis strongly an immobilized TG system could apply to continuous production of IMO.

• KSBB Journal
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• v.15 no.6
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• pp.566-572
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• 2000

Experimental studies were carried out to develop an osmotolerant mutant of Candida magnoliae JH and to determine the optimum concentrations of carbon and nitrogen sources to improve erythritol yield and productivity. Mutants of C. magnoliae JH were prepared by treatment with ethylmethane sulfonate, and osmotolerant mutants were isolated from the agar plate colonies containing 2.5 M KCI. Among the mutants isolated, one mutant M26 was finally selected based on erythritol yield and productivity. In shake flask culture, glucose proved to be the best carbon source and the optimum yeast extract concentration was 5 g/L based on 100 g/L glucose. The erythritol yield and productivity of mutant M26 were greater than wild type in 100 g/L glucose medium. in the fermentation experiments, erythritol production increased with increased glucose concentration, up to a limit of 250 g/L. The maximum concentration of erythritol achieved 127.5 g/L, and the yield and productivity of erythritol production were 51.0% and 0.63 g/L-h, respectively.

• KSBB Journal
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• v.17 no.1
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• pp.93-99
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• 2002

Two-stage fed-batch culture of Candide tropicalis that was designated primarily to cultivate the cell in the glucose medium (1st stage) and then produced the xylitol from xylose medium (2nd stage) was developed to improve a xylitol yield and productivity. In the growth stage, glucose was automatically supplied to the fermentor by pH-stat mode when the pH was up 5.7, When a feeding medium was added in order to reach the glucose and yeast extract concentrations up to 100 and 40 g/L, respectively, a high cell concentration and a relatively low ethanol concentration were obtained in 18.5 h culture. In the production stage, initial xylose concentration of 150 g/L was the most favorable for obtaining the final xylitol concentration and productivity. The addition of mineral salts was also enhanced a xylitol production. But the aeration rate was not significantly affected a xylitol production. When the addition of 16 g yeast extract and 232.5 g xylose powder at the production stage was used, xylitol yield and productivity were significantly increased. With these conditions, xylitol concentration, yield and productivity of 108.9 g/L, 74%) and 3.3 g/L·h, respectively, were obtained in a final volume of 1.58 L. The further addition of 16 g yeast extract and 232.5 g xylose powder increased the working volume partly (1.67 L) and resulted in a relatively high xylitol concentration, yield and productivity of 193 g/L, 70% and 3.6 g/L·h, respectively.

• Journal of Sensor Science and Technology
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• v.17 no.5
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• pp.350-360
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• 2008

In every large hospital, nurses must perform simple repetitive tasks such as measuring body temperature. Such tedious work reduces nurses' motivation to provide quality medical care, which is an important element of the medical services provided by a hospital. If a device were available to measure body temperature, nurses could focus on the more important aspects of providing quality medical care to the patients. However, body temperature is generally measured from the throat, anus, tympanum or armpit, where it is difficult to affix a patch type device. In addition, general body temperature measuring points shows moving artifact error; therefore, it is not good point to continually measure the temperature. In this paper, a patch type skin temperature measuring system was developed. To appropriately measure the skin temperature, a thermal transducer was implemented with a thin (0.5 mm) temperature sensor. The system is small and thin ($H6.6{\sim}5.3{\times}L35{\times}W24\;mm$), and weighs only 5 g including a battery, case and circuit; therefore, it is small and light enough to function as a patch type device. Moreover, the system worked for 5 days. To investigate differences between the experimental and conventional thermometer, simple clinical experiments were performed with 17 volunteers, and the result showed some correlation between the implemented system and conventional thermometer (Correlation coefficient = 0.647, P<0.1).

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.309-324
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• 2015

In this paper we introduce how to analyze survival data via a SRC-Stat statistical package. This provides classical survival analysis (e.g. Cox's proportional hazards models for univariate survival data) as well as advanced survival analysis such as shared and nested frailty models for multivariate survival data. We illustrate the use of our package with practical data sets.