• Asian-Australasian Journal of Animal Sciences
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• 제16권4호
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• pp.558-564
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• 2003

A $3{\times}3$ (Fe$\times$VA) experiment with repeats was designed to study the interaction between iron and vitamin A in broilers. 504 broilers were divided into 9 groups (50% males, 50% femals), each group with 4 repeats. Iron supplemental amount was 0, 30 and 60 mg/kg; Vitamin A supplemental amount was 750, 1,500 and 2,700 IU/kg. Iron concentration in liver, serum, tibia and duodenum and vitamin A concentration in liver and serum were measured, and erythrocyte count was also observed. Results showed with the increase of dietary supplemental iron levels, vitamin A concentration in liver significantly decreased lineally (p<0.05) (0.861, 0.671, 0.639 mg/100 g at the end of 4th week; 0.900, 0.765, 0.739 mg/100 g at the end of 7th week), and vitamin A concentration in serum significantly increased lineally (p<0.05) (82.725, 97.842, $109.475{\mu}g/100mL$ at the end of 4th week; 62.288, 91.900, $95.117{\mu}g/100mL$ at the end of 7th week), meaning iron could promote the mobilization of vitamin A from liver to serum. With the increase of dietary supplemental vitamin A levels, liver iron concentration decreased and serum iron concentration increased, vitamin A could promote the mobilization of iron from liver to blood. Iron concentration in Duodenum and tibia and erythrocyte count increased significantly with higher dietary vitamin A supplementation (p<0.01), vitamin A could promote iron absorption, iron mobilization from liver to target tissues and erythropoiesis. Effects of the interaction between iron and vitamin A on vitamin A concentrations in liver and serum, iron concentration in tibia and erythrocyte count were significant (p<0.05).

• 분석과학
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• 제33권1호
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• pp.49-57
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• 2020

Controlling the quality of indoor air is important in order to maintain a healthy life. In this study, we investigated the correlation between the hazardous substance concentration of indoor air and circulation based on different ventilation methods in the apartment, which is one of the representative housing types in Korea. As target substances, we considered the hazardous substances which are generated during the cooking process and radon gas which is originated from building materials. We measured the concentrations of carbon dioxide and fine particles in relation to type of food and ventilation methods in order to determine the change in the concentration levels of hazardous substances which are generated during the cooking process. On the other hand, we measured the concentration of radon gas before and after letting fresh air into a room through windows in order to determine the change in the concentration level of radon gas which is originated from building materials. The results show that turning on the ventilation fan plays a major role in reducing the concentration levels of hazardous substances in the kitchen, and that it is more effective to turn on the ventilation fan during cooking than after cooking to prevent the diffusion of hazardous materials produced by cooking through the indoor air. Also, the results indicate that letting fresh air into a room through windows more than one time a day is necessary to reduce the concentration level of radon gas in the room to safe concentration range.

• 한국환경보건학회지
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• 제37권1호
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• pp.50-56
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• 2011

The adsorption capacity of charcoal is a function of the airborne concentration of the target chemical. To evaluate the adsorption capacity of charcoal packed in the cartridges of air purifying respirators, breakthrough tests were conducted with carbon tetrachloride for three commercial cartridges (3M models #7251, #6000 and AX) at 25, 50, 100, 250 and 500 ppm. Adsorption capacities were calculated using a mass transfer balance equation derived from the curve fitting to the breakthrough curves obtained experimentally. Carbon micropore volumes were estimated by iteration to fit the Dubinin/Radushkevich (D/R) adsorption isotherm. They were 0.6566, 0.5727 and 0.3087 g/cc for #7251, #6000 and the AX cartridge, respectively. Above 100 ppm (at high challenge concentrations), #7251 and #6000 showed higher adsorption capacities. However, as the challenge concentration decreased, the adsorption capacities of #7251 and #6000 sharply dropped. On the other hand, the adsorption capacity of the AX cartridge showed little change with the decrease of the challenge concentration. Thus, the AX showed a higher adsorption capacity than #7251 and #6000 at the 5-50 ppm level. It is concluded that service-life tests of cartridges and adsorption capacity tests of charcoal should be conducted at challenge concentration levels reflecting actual working environmental conditions. Alternatively, it is recommended to use the D/R adsorption isotherm to extrapolate adsorption capacity at low concentration levels from the high concentration levels at which breakthrough tests are conducted, at a minimum of two different concentration levels.

• Biomolecules & Therapeutics
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• 제26권3호
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• pp.274-281
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• 2018

A previous study in humans demonstrated the sustained inhibitory effects of donepezil on acetylcholinesterase (AChE) activity; however, the effective concentration of donepezil in humans and animals is unclear. This study aimed to characterize the effective concentration of donepezil on AChE inhibition and impaired learning and memory in rodents. A pharmacokinetic study of donepezil showed a mean peak plasma concentration of donepezil after oral treatment (3 and 10 mg/kg) of approximately $1.2{\pm}0.4h$ and $1.4{\pm}0.5h$, respectively; absolute bioavailability was calculated as 3.6%. Further, AChE activity was inhibited by increasing plasma concentrations of donepezil, and a maximum inhibition of $31.5{\pm}5.7%$ was observed after donepezil treatment in hairless rats. Plasma AChE activity was negatively correlated with plasma donepezil concentration. The pharmacological effects of donepezil are dependent upon its concentration and AChE activity; therefore, we assessed the effects of donepezil on learning and memory using a Y-maze in mice. Donepezil treatment (3 mg/kg) significantly prevented the progression of scopolamine-induced memory impairment in mice. As the concentration of donepezil in the brain increased, the recovery of spontaneous alternations also improved; maximal improvement was observed at $46.5{\pm}3.5ng/g$ in the brain. In conclusion, our findings suggest that the AChE inhibitory activity and pharmacological effects of donepezil can be predicted by the concentration of donepezil. Further, $46.5{\pm}3.5ng/g$ donepezil is an efficacious target concentration in the brain for treating learning and memory impairment in rodents.

• 한국대기환경학회지
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• 제9권1호
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• pp.44-50
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• 1993

The suspended particulate matters had been collected by a cascade impactor having 9 size fragnated stages for 2 years (Dec. 1989 to Nov. 1991) in Kyung Hee University-Suwon Campus. The particulate matters were then collected on each stage by membrane filters. The weight concentration on each stage was estimated by a microbalance and further chemical element concentrations were determined by an XRF system. The study focused on developing of a receptor model using the TTFA (target transformation factor analysis) to apportion aerosol mass with the 30 ambient data sets. Each data set consists of the 8 size-ranged subdata sets characterized by 13 element variables. Even though a couple of sources could not be identified, three to five sources were extracted from each aerosol size-range, and then 9 statistical source profiles were generated. Finally, source contribution of particulate matters on each size-range could be estimated in Suwon area.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권1호
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• pp.25-29
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• 2000

The present study evaluated the body burden of aromatic VOCs in roadside and underground storekeepers. The Method Detection Limit(MDL) of the analytical system ranged from 0.2 to 0.4$\mu\textrm{g}$/m3 for the target VOCs. The recovery of the sampling system for the compounds was above 80%. For all the target compounds, the breath concentrations of the smokes were similar to or slightly higher than those of the nonsmokers for both the roadside and underground storekeepers. For Ethylbenzene, p-Xylene, and o-Xylene, the breath concentrations of the underground storekeepers were somewhat higher than those of the roadside storekeepers. In contrast, the breath m-xylene concentration of underground storekeepers was similar to that of roadside storekeepers. For both the roadside and underground storekeepers, the breath concentrations prior to and after work were not significantly different.

• Clinical and Experimental Pediatrics
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• 제54권9호
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• pp.359-362
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• 2011

There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation ($SpO_2$) is 90 to 93% with an intermittent review of the correlation between $SpO_2$ and the partial pressure of arterial oxygen tension ($PaO_2$). Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1617-1622
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• 2008

We report a new molecular detection process which measures the changes in the plasmon resonance peaks of periodic Au nanoparticle arrays fabricated using the electron beam lithography. As the Au nanoparticle arrays are modified by the chemical reaction in solutions having various concentrations of a target molecule, both the position and intensity of the plasmon peak change in proportion to the concentration of the target molecule. We expect that the process developed in this work can be employed for fine tuning of the plasmon peak wavelength and also for the optical detection of various kinds of molecules. Moreover, this method may improve the measurement accuracy compared with existing approaches that use only one change (peak wavelength or peak intensity) as a readout value for the molecular detection.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.411-414
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• 2002

Acylated homoserine lactones (AHLs) are membrane-permeant signal molecules responsible for biofilm formation of gram-negative bacteria via a unique mechanism known as quorum sensing. A target specific bioassay employing the AHL-responsive Agrobacterium tumefaciens reporter strain has been developed to identify new AHL-like compounds from natural products, which could be developed into antifouling compounds. By varying the X-gal concentration, incubation time, solvent for sample preparation and the sample loading procedure, it was possible to detect low level AHLs up to $10^1nM$. The length of the acyl chain of the AHLs was found to affect the sensitivity of this bioassay.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권6호
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• pp.747-751
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• 2010

본 연구에서는 기계 가독형 사전 정보를 이용하여 중의어 의미 태깅을 위한 학습에 사용될 양질의 의미부착 데이터를 자동 생성하여 중의어 태깅 정확도를 향상시키는 방법을 제안한다. 또한 중의어의 의미별로 특징있는 주변 단어를 원소로 갖는 의미그룹을 생성하고, 의미그룹내 중요 자질의 가중치 선정에 집중도 개념을 도입하여 태깅 정확도를 높인다. SENSEVAL-2 데이터를 사용하여 태깅 정확도를 평가한 결과 본 연구에서 제안한 방법이 기존의 방법보다 정확도를 향상시킨 것으로 나타났다.