• 전기화학회지
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• 제8권1호
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• pp.47-54
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• 2005

This article covers the fundamentals of stress-induced diffusion, focusing on the theoretical model for hydrogen transport through self-stressed electrode. First, the relationship between hydrogen diffusion and macroscopic deformation of the electrode specimen was briefly introduced, and then it was classified into the diffusion-elastic and elasto-diffusive phenomena. Next, the transport equation for the flux of hydrogen caused simultaneously by both the concentration gradient and the stress gradient was theoretically derived. Finally, stress-induced diffusion was discussed on the basis of the numerical solutions to the derived transport equation under the permeable and impermeable boundary conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제32권3호
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• pp.442-451
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• 2019

Objective: This study was conducted to investigate the effect of transport stress on physiological and hematological responses and milk performance in lactating dairy cows. Methods: Ten lactating dairy cows were randomly divided into 2 groups. The treatment group (TG) was transported 200 km for 4 h by truck, and the control group (NTG) was restrained by stanchion for 4 h in Konkuk University farm. Blood and milk samples were collected at 24 h pre-transport; 1, 2, and 4 h during transport; and 2, 24, and 48 h post-transport. Milk yields were measured at 24 h pre-transport, 0 h during transport, and 24, 48, and 72 h post-transport. Results: Leukocyte, neutrophil, and monocyte numbers in the TG were significantly higher than those of the NTG at each experimental time point. Lymphocyte numbers in the TG were significantly (p<0.05) higher than those of the NTG at 48 h post-transport. Additionally, the neutrophil:lymphocyte ratio of the TG was 45% and 46% higher than that of the NTG at 4 h during transport and 2 h post-transport, respectively. There were no significant differences in erythrocyte numbers, hemoglobin concentrations, platelet numbers, and hematocrit percentages between two groups. Cortisol levels in the TG were significantly (p<0.05) higher than those in the NTG. Milk yields in the TG were lower than those in the NTG. The somatic cell count (SCC) of the TG was significantly (p<0.05) higher than that of the NTG at 1 and 2 h during transport; that of the TG increased dramatically at 1 h during transport and gradually decreased subsequently. Conclusion: Transport stress increased blood parameters including leucocyte, neutrophil, and monocyte numbers by increased cortisol levels, but did not affect erythrocytes, hemoglobin and hematocrit levels. Additionally, transport resulted in a decrease in milk yield and reduced milk quality owing to an increase in milk SCC.

• Journal of Pharmaceutical Investigation
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• 제38권5호
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• pp.295-302
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• 2008

In the present study, we examined the changes of uptake and efflux of taurine under various conditions inducing oxidative stress using rat conditionally immortalized syncytiotrophoblast cell line, TR-TBT cell, as blood-placental barrier in vitro model. In addition, we identified the characteristics of taurine transport in TR-TBT cells including general features, besides effect of calcium ion on taurine transport. Taurine uptake showed time, $Na^+$ and $Cl^-$ dependency, and was decreased by PKC activator in TR-TBT cells. Also, calcium free condition decreased taurine uptake and evoked taurine efflux in the cells. Oxidative stress induced the change of taurine transport in TR-TBT cells, but the changes were different depending on the types of stimulation inducing oxidative stress. The taurine uptake was increased by TNF-$\alpha$, LPS and DEM stimulation but decreased by $H_2O_2$ and NO stimulation. Also, the taurine efflux was regulated by TNF-$\alpha$ stimulation. In conclusion, the taurine transport through the blood-placental barrier was regulated in oxidative stress conditions, and these results demonstrated that oxidative stress affected the taurine supplies to fetus and taurine level of fetus.

• 대한수의학회지
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• 제41권4호
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• pp.603-609
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• 2001

A transport stress is one of the main causes of economic losses and physiological dysfunction. The present study has been performed to suggest a method to decrease the adverse effects above mentioned from transport. The groups were prepared as follows; (1) Control group : 4 cattle transported for 5 hrs (274 km) without any treatment, (2) Treatment group : 4 cattle treated with electrolyte-mineral solution (I.V.) at 1 hr before the enrollment of transport under same experimental condition with Control group. The blood specimens were collected at 1 hr before transport, 2.3 hrs (135 km) and 5 hrs (274 km) after the enrollment of transport, and 1, 6 and 18 hrs after fulfillment of transport. The collected blood specimens were analyzed for cortisol and epinephrine. Core temperature and heart rate were measured with active biotelemetry in every 30 minutes from 0.5 hr before the start of transport to 18 hrs after the end of transport. In results, the level of cortisol considerably increased to the peak either in Control group ($5.3{\pm}1.3{\mu}g/d{\ell}$) and in Treatment group ($4.0{\pm}2.6{\mu}g/d{\ell}$) at 2.3 hrs in transport. The concentration of epinephrine of Treatment group had been higher than that of Control group from the start of transport to 18 hrs after the fulfillment of transport. Particularly there was the biggest gap between Control and Treatment groups, $424.0{\pm}194.1pg/m{\ell}$ and $209.1{\pm}65.1pg/m{\ell}$ respectively, at 6 hrs after the end of transport. The heart rates were considerably increased either in Control group ($81.5{\pm}18.5$ to $126.3{\pm}7.8beats/min$) and in Treatment group ($114.3{\pm}14.4$ to $140.8{\pm}22.4beats/min$) with the enrollment of transport. These results indicate that the concentration of cortisol and the heart rate were pertinent to cognitive parameters to evaluate physiological responses against stress such as transport. In addition, the intravenous administration of electrolyte-mineral solution could be suggested as the method to decrease the adverse effects from a transport stress.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1782-1798
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• 2004

A numerical study of a natural convection in a rectangular cavity with the low-Reynolds-number differential stress and flux model is presented. The primary emphasis of the study is placed on the investigation of the accuracy and numerical stability of the low-Reynolds-number differential stress and flux model for a natural convection problem. The turbulence model considered in the study is that developed by Peeters and Henkes (1992) and further refined by Dol and Hanjalic (2001), and this model is applied to the prediction of a natural convection in a rectangular cavity together with the two-layer model, the shear stress transport model and the time-scale bound ν$^2$- f model, all with an algebraic heat flux model. The computed results are compared with the experimental data commonly used for the validation of the turbulence models. It is shown that the low-Reynolds-number differential stress and flux model predicts well the mean velocity and temperature, the vertical velocity fluctuation, the Reynolds shear stress, the horizontal turbulent heat flux, the local Nusselt number and the wall shear stress, but slightly under-predicts the vertical turbulent heat flux. The performance of the ν$^2$- f model is comparable to that of the low-Reynolds-number differential stress and flux model except for the over-prediction of the horizontal turbulent heat flux. The two-layer model predicts poorly the mean vertical velocity component and under-predicts the wall shear stress and the local Nusselt number. The shear stress transport model predicts well the mean velocity, but the general performance of the shear stress transport model is nearly the same as that of the two-layer model, under-predicting the local Nusselt number and the turbulent quantities.

• 한국가시화정보학회지
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• 제20권1호
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• pp.38-44
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• 2022

An interscale transport of the turbulent kinetic energy (TKE) and Reynolds shear stress (RSS) is examined in an adverse pressure gradient (APG) turbulent boundary layer (TBL). The direct numerical simulation data of an APG TBL at Re_τ = 834 and β = 1.45 is employed. The TKE and RSS transport equations are divided into large and small scales, leading to the introduction of interscale transport. The TKE mainly transfers from large scales to small ones in the outer region, and vice versa for the RSS. An interscale transport of TKE and inverse interscale transport of RSS are amplified by APG, and the latter results in the increase in large scales of TKE production. Some of outer large scales of enhanced TKE transfer to small scales and then dissipate by viscosity, and the remains dissipate turbulent-non-turbulent interfaces by turbulent transport.

• Fisheries and Aquatic Sciences
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• 제1권1호
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• pp.48-62
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• 1998

Seasonal volume transport on the Texas-Louisiana continental shelf is investigated in terms of objectively fitted transport streamfunction fields based on the current meter data of the Texas­Louisiana Shelf Circulation and Transport Processes Study. Adopted here for the objective mapping is a method employing a two-dimensional truncated Fourier representation of the streamfunction over a domain, with the amplitudes determined by least square fit of the observation. The fitting was done with depth-averaged flow rather than depth-integrated flow to reduce the root-mean-square error. The fitting process filters out $11\%$ of the kinetic energy in the monthly mean transport fields. The shelf-wide pattern of streamfunction fields is similar to that of near-surface velocity fields over the region. The nearshore transport, about 0.1 to 0.3 Sv $(1 Sv= 10^6\;m^3/sec)$, is well correlated with the seasonal signal of along-shelf wind stress. The spring transport is weak compared to other seasons in the inner shelf region. The transport along the shelf break is large and variable. In the southwestern shelf break, transport amounts up to 4.7 Sv, which is associated with the activities of the encroaching of energetic anticyclonic eddies originated in Loop Current of the eastern Gulf of Mexico. The first empirical orthogonal function (EOF) of streamfunction variability contains $67.3\%$ of the variance and shows a simple, shelf-wide, along-shelf pattern of transport. The amplitude evolution of the first EOF is highly correlated (correlation coefficient: 0.88) with the evolution of the along-shelf wind stress. This provides strong evidence that the large portion of seasonal variation of the shelf transport is wind-forced. The second EOF contains $23.7\%$ of the variance and shows eddy activities at the southwestern shelf break. The correlation coefficient between the amplitudes of the second EOF and wind stress is 0.42. We assume that this mode is coupled a periodic inner shelf process with a non-periodic eddy process on the shelf break. The third EOF (accounting for $7.2\% of the variance) shows several cell structures near the shelf break associated with the variability of the Loop Current Eddies. The amplitude time series of the third EOF show little correlation with the along-shelf wind.

• BMB Reports
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• 제39권4호
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• pp.394-399
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• 2006

The transport of putrescine into a moderately salt tolerant cyanobacterium Synechocystis sp. PCC 6803 was characterized by measuring the uptake of radioactively-labeled putrescine. Putrescine transport showed saturation kinetics with an apparent $K_m$ of $92{\pm}10\;{\mu}M$ and $V_{max}$ of $0.33{\pm}0.05\;nmol/min/mg$ protein. The transport of putrescine was pH-dependent with highest activity at pH 7.0. Strong inhibition of putrescine transport was caused by spermine and spermidine whereas only slight inhibition was observed by the addition of various amino acids. These results suggest that the transport system in Synechocystis sp. PCC 6803 is highly specific for polyamines. Putrescine transport is energy-dependent as evidenced by the inhibition by various metabolic inhibitors and ionophores. Slow growth was observed in cells grown under salt stress. Addition of low concentration of putrescine could restore growth almost to the level observed in the absence of salt stress. Upshift of the external osmolality generated by either NaCl or sorbitol caused an increased putrescine transport with an optimum 2-fold increase at 20 mosmol/kg. The stimulation of putrescine transport mediated by osmotic upshift was abolished in chloramphenicol-treated cells, suggesting possible involvement of an inducible transport system.

• 한국축산시설환경학회지
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• 제17권2호
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• pp.101-106
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• 2011

출하취급과 출하차량 형태가 출하돈의 혈액성상과 도체품질에 미치는 영향을 분석하기 위하여 개방형 트럭과 밀폐형 박스 트럭으로 구분하고 각각의 차량형태에 대하여 출하취급을 최대한 부드럽게 혹은 상차, 하차, 계류 과정에 전기봉 사용을 포함하여 고의적으로 거칠게 하는 그룹으로 나누어 체중 약 110kg에 출하되는 삼원교잡종 비육돈 144두를 공시하여 조사, 분석하였다. 모든 출하돈은 계류장 도착 후 3시간 동안 계류하였다. 혈액은 도축직후에 채취하였고 배최장근 시료는 도축 12시간 후 (overnight)에 채취하여 분석에 사용하였다. 출하돈의 스트레스와 관련된 혈중 glucose, cortisol, creatine kinase 및 lactate dehydrogenase 농도는 출하취급을 부드럽게 한 그룹에 비하여 고의적으로 거칠게 취급한 그룹에서 높았으며 결과적으로 PSE 발생율이 높게 나타났다. 그러나 출하차량은 출하돈의 스트레스 관련 혈액성상과 도체품질에 영향을 미치지 않는 것으로 나타났다. 결론적으로 부드러운 출하취급은 PSE 발생을 줄이기 위한 좋은 방법이 될 수 있다. 그러나 출하취급이 거칠면 혈중 스트레스 관련 지표들의 농도가 증가하여 동물복지를 나쁘게 할 수 있어 거친 취급은 반드시 피해야 할 것이다. 또한 출하차량은 출하돈의 스트레스와 도체품질 등 직접적인 측면보다는 외관, 악취 등 간접적인 측면에서 검토되어야 할 것으로 판단된다.

• 대한교통학회:학술대회논문집
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• 대한교통학회 1998년도 Proceedings The 4th International Transport Symposium
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• pp.198-203
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• 1998

Through an analyses of the necessity and the practical meaning of the assets operation in railway transport enterprises, the authors argue that a railway transport enterprise shall lay equal stress on assets operation and production management, and suggest to take concrete steps on the basis of the aforesaid management strategy.