• Nutrition Research and Practice
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• 제3권2호
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• pp.122-127
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• 2009

Folate is generally considered as a safe water-soluble vitamin for supplementation. However, we do not have enough information to confirm the potential effects and safety of folate supplementation and the interaction with vitamin $B_{12}$ deficiency. It has been hypothesized that a greater methyl group supply could lead to compensation for vitamin $B_{12}$ deficiency. On this basis, the present study was conducted to examine the effects of high-dose folic acid (FA) supplementation on biomarkers involved in the methionine cycle in vitamin $B_{12}$-deficient rats. Sprague-Dawley rats were fed diets containing either 0 or $100{\mu}g$ (daily dietary requirement) vitamin $B_{12}/kg$ diet with either 2 mg (daily dietary requirement) or 100 mg FA/kg diet for six weeks. Vitamin $B_{12}$-deficiency resulted in increased plasma homocysteine (p<0.01), which was normalized by dietary supplementation of high-dose FA (p<0.01). However, FA supplementation and vitamin $B_{12}$ deficiency did not alter hepatic and brain S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) concentrations and hepatic DNA methylation. These results indicated that supplementation of high-dose FA improved homocysteinemia in vitamin $B_{12}$-deficiency but did not change SAM and SAH, the main biomarkers of methylating reaction.

• 한국식품저장유통학회지
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• 제24권4호
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• pp.505-509
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• 2017

Water vapor adsorption kinetics of vacuum-dried jujube powder were investigated in temperature and relative humidity ranges of 10 to $40^{\circ}C$ and 32 to 75%, respectively. Water vapor was initially adsorbed rapidly and then reached equilibrium condition slowly. Reaction rate constant for water vapor adsorption of vacuum-dried jujube powder increased with an increase in temperature. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Good straight lines were obtained with plotting of $1/(m-m_0)$ vs. 1/t. It was found that water vapor adsorption kinetics of vacuum-dried jujube powder was accurately described by a simple empirical model, and temperature dependency of the reaction rate constant followed the Arrhenius-type equation. The activation energy ranged from 50.90 to 56.00 kJ/mol depending on relative humidity. Arrhenius kinetic parameters ($E_a$ and $k_0$) for water vapor adsorption by vacuum-dried jujube powder showed an effect between the parameters with the isokinetic temperature of 302.51 K. The information on water vapor adsorption kinetics of vacuum-dried jujube powder can be used to establish the optimum condition for storage and processing of jujube.

• Safety and Health at Work
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• 제14권4호
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• pp.406-414
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• 2023

Background: This study examined age-group differences in the rate, severity, and cost of injuries among construction workers to support evidence-based worker safety and health interventions in the construction industry. Methods: Ohio workers' compensation claims for construction workers were used to estimate claim rates and costs by age group. We analyzed claims data auto-coded into five event/exposure categories: transportation incidents; slips, trips, and falls (STFs); exposure to harmful substances and environments; contact with objects and equipment (COB); overexertion and bodily reaction. American Community Survey data were used to determine the percentage of workers in each age group. Results: From 2007-2017, among 72,416 accepted injury claims for ~166,000 construction full-time equivalent (FTE) per year, nearly half were caused by COB, followed by STFs (20%) and overexertion (20%). Claim rates related to COB and exposure to harmful substances and environments were highest among those 18-24 years old, with claim rates of 313.5 and 25.9 per 10,000 FTE, respectively. STFs increased with age, with the highest claim rates for those 55-64 years old (94.2 claims per 10,000 FTE). Overexertion claim rates increased and then declined with age, with the highest claim rate for those 35-44 years old (87.3 per 10,000 FTE). While younger workers had higher injury rates, older workers had higher proportions of lost-time claims and higher costs per claim. The total cost per FTE was highest for those 45-54 years old ($1,122 per FTE). Conclusion: The variation in rates of injury types by age suggests that age-specific prevention strategies may be useful.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.7-7
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• 2000

A high $T_c$ SQUID system is developed for the application to biological immunoassay. In this application, magnetic nanoparticles are used as magnetic markers to perform immunoassay, i.e., to detect binding reaction between an antigen and its antibody. The antibody is labeled with ${\gamma}-Fe_2O_3\;(or\;Fe_3O_4)$ nanoparticles, and the binding reaction can be magnetically detected by measuring the magnetic field from the nanoparticles. Design and set up of the system is described. The system consists of (1) SQUID magnetometer or gradiometer made of 30-deg. bicrystal junctions, (2) field and compensation coils to apply the magnetic field of about 1 mT, (3) special Dewar to realize a 2 mm-distance between the SQUID and the sample, (4) two layers of cylindrical shielding to reduce the extemal magnetic noise to about 1/100, and (5) an electric slider to move the sample with a speed of 10 mm/sec. The sensitivity of the system is studied in terms of detectable magnetic flux. For the measurement bandwidth from 0.2 Hz to 10 Hz, minimum-detectable amplitude of the magnetic flux is $0.8\;m\;{\Phi}_o$ and $0.25\;m{\Phi}_o$ for the magnetometer and the gradiometer, respectively, when the magnetic field of 1 mT is applied. The difference between them is due to the residual environmental noise, and the applied magnetic field does not increase the system noise. The corresponding weight of the magnetic markers is 1 ng and 310 pg, respectively. An experiment is also conducted to measure antigen-antibody reaction with the present system. It is shown that the sensitivity of the present system is 10 times better than that of the conventional method using an optical marker. A one order of magnitude improvement of sensitivity will be realized by the sophistication of the present system.

• Preventive Nutrition and Food Science
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• 제12권2호
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• pp.111-114
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• 2007

Water vapor adsorption kinetics of Inonotus mushroom powders were investigated in temperature and water activity ranges of 20 to 40$^{\circ}C$ and 0.30 to 0.81, respectively. Initial water vapor adsorption rate of mushroom powders increased with increases in temperature and water activity. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Water vapor adsorption kinetics of the mushroom powders can be well described by a simple empirical model. Temperature dependency of the reaction rate constant followed the Arrhenius relationship. The activation energy ranged from 56.86 to 91.35 kJ/mol depending on water activity. Kinetic compensation relationship was observed between k$_o$ and E$_a$ with the isokinetic temperature of 790.27 K.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권3호
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• pp.188-196
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• 2016

For the balancing control of a one-wheel mobile robot, CMG (Control Moment Gyro) can be used as a gyroscopic actuator. Balancing control has to be done in the roll angle direction by an induced gyroscopic motion. Since the dedicated CMG cannot produce the rolling motion of the body directly, the yawing motion with the help of the frictional reaction can be used. The dynamic uncertainties including the chattering of the control input, disturbances, and vibration during the flipping control of the high rotating flywheel, however, cause ill effect on the balancing performance and even lead to the instability of the system. Fuzzy compensation is introduced as an auxiliary control method to prevent the robot from the failure due to leaning aside of the flywheel. Simulation studies are conducted to see the feasibility of the proposed control method. In addition, experimental studies are conducted for the verification of the proposed control.

• Journal of Plant Biology
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• 제21권1_4호
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• pp.33-38
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• 1978

Phosphate absorption from a Na2H32PO4 solution by Oryza sativa L. was studied in order to elucidate kinetic mechanisms of ion transport. The rates of phosphate absorption from different concentraitons indicated the presence of dual mechanisms in root tips, one in the low (1$\times$10-6 to 8$\times$10-5M) and the other in the high (1$\times$10-4 to 8$\times$10-3M). A phosphate compensation point of phosphate transport was revealed with a 1$\times$10-6M solution of Na2H32PO4. The kinetic model that ion transport involves an exchange reaction of absorption and desorptin is prosposed as follows: where C represents an ionic-specific organic carrier in the membrane; M, Mo and Mi are the mineral ions, M-outside and M-inside; MC is a carrier-ion complex; and the K's represent rate constants. In this model, the Mi velocity, v, is given by: {{{{v= {dMi} over {dt}= {(K1K3Mo-K2K4Mi) Ct} over {(K2＋K3)＋K1Mo＋K4Mi} }} where Ct is equal to C＋MC, and t is time.

• 산업경영시스템학회지
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• 제24권69호
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• pp.36-49
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• 2001

Group level discriminations are observed in employment relations and other transactions in the form of residential occupational and production segregation and differential treatments. Recent developments in the rational theories of discrimination both on the market level and the non-market level are reviewed in terms of their relative strengths, weaknesses and complementarities. Taste discrimination could remain much suppressed in the market but could effect much chain reaction through various ways of statistical discrimination, price discrimination, human capital investment and segregation. Taste discrimination could also take the more structured form of co-workers' requiring compensation for reduced productivity due to increasing interactions with members of different language and culture in a non-segregative system. If could also be viewed in the framework of brand learning models. Non-market models of discrimination are seen to be an essential part to explain extended modes of discrimination.

• 한국산학기술학회논문지
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• 제16권6호
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• pp.3829-3836
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• 2015

기업의 실제적인 불만처리 반응은 불만 고객의 이탈을 줄이는 기업의 중요한 성공요인이다. 이에 본 연구는 기업의 불만처리 반응을 실질적인 보상, 종업원(직원)의 호의적인 행동 그리고 기업의 절차로 구분하였다. 이때 고객의 정의인식인 공정성 지각이 신뢰와 만족에 미치는 영향을 실증적으로 검증하여 실제적인 기업 반응의 중요성을 제시하고자 한다. 연구 대상은 기업에게 직접적으로 불만을 제기한 경험이 있는 210명의 설문 자료를 SPSS, AMOS를 이용하여 분석하였다. 연구 결과를 요약하면 불만고객에 대한 보상은 공정성에 유의한 영향을 미치는 것으로 나타났으며, 종업원의 호의적인 태도도 공정성에 유의한 영향을 미치는 것으로 나타났다. 불만에 대한 기업의 절차 역시 공정성에 유의한 영향을 미치는 것으로 본 연구에서는 분석되었다. 특히, 이러한 공정성은 정의 인식으로 고객의 미래 행동인 신뢰와 만족에 영향을 미치는 것으로 나타났다. 이런 연구 결과에 근거하여 시사점을 제시하고 미래 연구를 제안하였다.

• 한국농림기상학회지
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• 제8권2호
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• pp.61-67
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• 2006

내음성정도가 서로 다른 두 수종 먼나무와 붓순나무를 대상으로 높은 광도조건인 자연상태와 낮은 광도 조건인 비음 처리구로 나누어, 두 수종간의 적응 반응을 비교하였다. 두 수종의 묘목을 처리구에서 각각 1년간 비음처리하였을 때, 엽록소함량과 광합성계, 엽육세포내 $CO_2$농도, 수분이용효율의 특성을 조사하였다. 엽록소 함량은 두 수종모두 자연조건(full sunlight)일 때, 비음처리구에 비하여 낮은 엽록소 함량들(Chl a, Chl b, Chl a+b)을 나타냈으며, 붓순나무에서 특히 자연조건과 비음 처리구간의 엽록소 함량의 차이가 크게 나타났다. 한편, 중용수인 먼나무는 PPFD $1000\;{\mu}mol\;m^{-2}s^{-1}$ 이상 일 때, 자연조건(full sunlight)에서 높은 광합성율과 높은 수분이용효율을 보였지만, PPFD $1000\;{\mu}mol\;m^{-2}s^{-1}$ 이하에서는 비음처리구에서 자연조건에 비해 더 높은 광합성율과, 수분이용효율을 나타냈다. 이에 반해 붓순나무는 모든 광도에서 비음처리를 하지 않은 묘목이 비음처리를 한 묘목에 비해 낮은 광합성율과 수분이용효율을 나타냈다. 먼나무가 탄력적으로 광도변화에 따라 유동성 있는 반응을 보이는 것에 비해 내음성이 강한 붓순나무는 광환경 변화에 따른 민감성이 낮게 나타나는 것을 알 수 있었다.