• 동아시아식생활학회지
• /
• 제10권3호
• /
• pp.239-244
• /
• 2000

Effects of acetic acid, malic acid and citric acid on copper dissolution from new and used copper saucepans at different concentrations (0, 0.02. 0.04, 0.1 0.2, 0.4, 1.0, 2.0, 4.0%), different boiling times (0,10, 20. 30, 40, 50, 60mins.), and different temperatures (5, 20, 40, 60, 80, 10$0^{\circ}C$ ) were investigated. As acetic acid concentration increases, copper content increases. Copper dissolution concentration from copper saucepans at boiling in malic acid increases more than in acetic acid or citric acid. At above 6$0^{\circ}C$, as the temperature increases, the concentration of copper dissolved from copper saucepans also increases. As boiling time increases, the concentration of copper dissolved from copper saucepans also increases. In addition, through repeated use, the concentration of copper increases as well. And copper concentration dissolves in large amounts from used saucepans rather than new saucepans. The dissolution of copper with distilled water by repeated use does not dissolve at all. 1% acetic acid dissolves in large quantities.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제5권1호
• /
• pp.17-22
• /
• 2000

The separation of tryptophan enantiomers was carried out with medium-pressure liquid chromatography using BSA (bovine serum albumin)-bonded silica as a chiral stationary phase. The influence of various experimental factors such as pH and ionic strength of mobile phase, separation temperature, and the presence of organic additives on the resolution was studied. In order to expand this system to preparative scale, the loadability of sample and the stability of stationary phase for repeated use were also examined. The separation of tryptophan enantiomers was successful with this system. The data indicated that a higher separation factor (a) was obtained at a higher pH and lower temperature and ionic strength in mobile phase. Addition of organic additives (acetonitrile and 2-propanol) in mobile phase contributed to reduce the retention time of L-tryptophan. About $30\%$ of the separation factor was reduced after 80 days of repeated use.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.521-524
• /
• 2006

This study is about the production and properties of waste concrete powder that recycling aggregate is crushed to the waste concrete. We researched the generation and the disposal of recycled concrete powder. It is chemica] and physical features that is compared and analysis according to its production system and repeated crushing of time. Recycled concrete powder is more generated wet process than drying process. In addition, the more it is repeated crushing of time, the more recycled concrete powder is generated. Recycled concrete powder is discovered that wet process is larger of the specific area, lower density and particle size.

• 한국염색가공학회지
• /
• 제11권3호
• /
• pp.23-31
• /
• 1999

In order to investigate the detergency of the mixture of compact detergent and bleaching agent to fabric stained with a coffee and a red wine, respectively, and a japanese wet stained fabrics, to evaluation of detergency was studied under various washing conditions. In order to study the effect of alkaline agent addition on the detergency, the soda ash was added in the compact detergent system. The results are as follows : In a low temperature washing condition, the alkalinity of washing liquor effected more the removal of the composite stained fabrics than that of oilic stained fabrics. For the colored stained fabric such as red wine stained sample, the influence of the repeated washing treatment on the detergency was not significant factor. On the other hand, the influence of the repeated washing treatment for the coffee stained and japanese wet stained fabric on the detergency was gradually increased.

• 대한후두음성언어의학회지
• /
• 제31권1호
• /
• pp.7-12
• /
• 2020

Recurrent respiratory papillomatosis (RRP) is characterized by repeated recurrence in the respiratory system, such as the pharynx, larynx, and trachea, caused by the human papilloma virus. The main treatment is surgical removal of the papilloma. However repeated recurrence of RRP in multiple areas is burdened for the surgeon. In addition to the surgery, various adjuvant therapies have been studied to reduce the recurrence. Literature review was conducted with a focus on the adjuvant treatments for RRP.

• 한국의류학회지
• /
• 제34권11호
• /
• pp.1798-1811
• /
• 2010

This research evaluates the changes in the comfort-related properties of high-density fabric, such as moisture permeability and waterproofness, in order to assess the relative importance of laundry conditions for clothing properties after repeated laundering and suggest the best laundering conditions for high-density fabric through the identification of the most influential factor. A commercial high-density fabric was washed 25 times in a drum-type washer using nine different laundry conditions based on profiles derived from a fractional factorial design. To evaluate the changes in the comfort-related properties of the fabric, pore size, air permeability, water vapor transport, water repellency, and water resistance were measured. The comfort-related properties of the fabric deteriorated after repeated laundering by the damaged surface finish; in addition, the damaged surface also changed the pore size. As a result, the water repellency and water resistance decreased. The detergent was the most responsible factor to change the properties among the four factors of detergent, hardness, temperature, and RPM. The best laundering conditions for the fabric was a neutral detergent, soft water of 70ppm, a temperature of $15^{\circ}C$, and 30rpm.

• Journal of Microbiology and Biotechnology
• /
• 제25권3호
• /
• pp.366-374
• /
• 2015

Herein, we established a repeated-batch process for ethanol production from glycerol by immobilized Pachysolen tannophilus. The aim of this study was to develop a more practical and applicable ethanol production process for biofuel. In particular, using industrial-grade medium ingredients, the microaeration rate was optimized for maximization of the ethanol production, and the relevant metabolic parameters were then analyzed. The microaeration rate of 0.11 vvm, which is far lower than those occurring in a shaking flask culture, was found to be the optimal value for ethanol production from glycerol. In addition, it was found that, among those tested, Celite was a more appropriate carrier for the immobilization of P. tannophilus to induce production of ethanol from glycerol. Finally, through a repeated-batch culture, the ethanol yield (Y_e/g) of 0.126 ± 0.017 g-ethanol/g-glycerol (n = 4) was obtained, and this value was remarkably comparable with a previous report. In the future, it is expected that the results of this study will be applied for the development of a more practical and profitable long-term ethanol production process, thanks to the industrial-grade medium preparation, simple immobilization method, and easy repeated-batch operation.

• 혜화의학회지
• /
• 제22권1호
• /
• pp.171-184
• /
• 2013

Single-and repeated-dose toxicities of Compound K (CK) were evaluated according to Toxicity Test Guidelines of Korea Food and Drug Administration using Sprague-Dawley rats. For single-dose toxicity study, CK was dissolved in drinking water, orally administered and examined for 14 days. As results, CK up to a dose of 5,000 mg/kg, the limited dose, neither induced death, clinical signs and necropsy findings, nor affected body weight gain and organ weights, in which 10% lethal dose could not be estimated. Based on the results of single-dose toxicity test, CK was administered at doses of 500, 1,000 or 2,000 mg/kg for 28 days for the evaluation of repeated-dose toxicity. All doses including the limited dose (2,000 mg/kg) of CK did not cause any abnormalities of rats, including mortality, clinical signs, body weight gain, feed/water consumption, necropsy findings, organ weights, hematology, blood biochemistry. Rather, high doses (1,000 - 2,000 mg/kg) of CK reduced the serum levels of alanine transaminase (ALT), aspartate transaminase (AST), creatinine phosphokinase (CPK), lactate dehydrogenase (LDH) and triglycerides, in addition to an increase in glucose, indicative of protective effects on hepatic and muscular injuries. Thus, both maximum tolerable dose (MTD) and no observed adverse effect level (NOAEL) were not determined. The results indicate that long-term intake of high-dose CK might not induce general adverse effects.

• 치위생과학회지
• /
• 제17권5호
• /
• pp.423-432
• /
• 2017

This study aimed to investigate the effect of repeated oral health education on the oral health of preschool children. This study classified the control group of children of 5~6 years of age where the oral health education was conducted one time, and the experiment group where the oral health education was conducted 4 times. The oral health conditions of each group and their risk of developing dental caries were also assessed. No significant difference was observed in the participants in terms of general characteristics, oral health conditions, risk of developing dental caries, and oral health behavior after oral health education. The two groups did not show a significant difference (p<0.001) in dental plaque index before and after oral health education, and showed a significant difference (p<0.001) according to the number of education sessions. Before oral health education, the participants in both groups were brushing their teeth incorrectly. However, after the third session, 56.7% of the participants in the experimental group and 9.4% in the control group used the correct method of tooth brushing. A significant difference was observed between the two groups (p<0.05). In addition, when the tooth-brushing time was compared, the two groups showed a significant difference (p<0.001), and a significant difference was observed in terms of the number of education sessions (p<0.05). In summary, repeated oral health education had significant influences on the dental plaque index, tooth-brushing method, brushing occlusal surfaces, and tooth-brushing time. Therefore, when oral health education is carried out, repeated oral health education in children is more effective than one-time oral health education as reflected in the changes in dental plaque index and oral health behavior. Moreover, oral health education is considered effective in changing the oral health behavior of children when conducted at least 3 times.

• Biomolecules & Therapeutics
• /
• 제18권1호
• /
• pp.111-121
• /
• 2010

In order to investigate the preliminary repeat oral dose toxicity and to determine the highest dosage for further 4-week repeated dose toxicity test, Low Molecular Weight Fucoidan (LMF) has been showed various pharmacological effects, was orally administered to female and male rats, once a day for 14 days at dose levels of 2,000, 1,000, 500 and 0 (vehicle control) mg/kg (body weights) in a volume of 10 ml/kg. The mortality and changes on the body weights, clinical signs, hematology, serum biochemistry and gross observations were monitored with organ weight and histopathology of principle organs. As the results of 14-day repeated oral treatment of LMF, no LMF treatment related mortalities were detected up to 2,000 mg/kg in both male and female rats, respectively. In addition, no noticeable changes on the body weight and clinical signs were detected except for significant decreases on the body weights and gains restricted to male 2,000 mg/kg treated groups as compared with male vehicle control. No meaningful changes on the organ weights, hematological, serum biochemistrical, gross and histopathological findings were observed. Therefore the highest dosage in the 4-week repeated dose toxicity test is suggested as 2,000 mg/kg in both female and male rats, respectively.