• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.261-268
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• 2019

Climate change and drought stress are having profound impacts on crop growth and development by altering crop physiological processes including photosynthetic activity. But finding a rapid, efficient, and non-destructive method for estimating environmental stress responses in the leaf and canopy is still a difficult issue for remote sensing research. We compared the relationships between photochemical reflectance index(PRI) and various optical and experimental indices on soybean drought stress under climate change conditions. Canopy photosynthesis trait, biomass change, chlorophyll fluorescence(Fv/Fm), stomatal conductance showed significant correlations with midday PRI value across the drought stress period under various climate conditions. In high temperature treatment, PRI were more sensitive to enhanced drought stress, demonstrating the negative effect of the high temperature on the drought stress. But high CO₂ concentration alleviated the midday depression of both photosynthesis and PRI. Although air temperature and CO₂ concentration could affect PRI interpretation and assessment of canopy radiation use efficiency(RUE), PRI was significantly correlated with canopy RUE both under climate change and drought stress conditions, indicating the applicability of PRI for tracking the drought stress responses in soybean. However, it is necessary to develop an integrated model for stress diagnosis using PRI at canopy level by minimizing the influence of physical and physiological factors on PRI and incorporating the effects of other vegetation indices.

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.359-364
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• 1999

The effect of Salicylic acid (SA) on the leaf growth, chlorophyll content, photosynthesis, stomatal conductance in Commelina communis L. was investigated. C. communis which was grown in Hoagland solution containing 1 mM SA during 3 weeks resulted in a significant reduction of leaf length, width and area. 1 mM SA reduced about 10% of the leaf area at 1 week and 2 weeks, but inhibited 22% of the leaf area at 3 weeks. SA also showed great effect on the reduction of chlorophyll content. SA reduced 47% and 53% of chlorophyll content each at 2 weeks and 3 weeks when it was compared with the control. Chlorophyll a/b ratio in SA treated sample was increased at 3 weeks representing that SA was sensitive to chlorophyll b. The treatment of SA did not inhibit the activity of PSII＋PSI, PSII and PSI. This result indicates that SA did not show direct effect oil the photosynthetic electron transport activity. However, when C. communis was grown in Hoagland solution containing I mM SA fer long period, SA showed clear inhibition of photosyhthesis in intact leaves. The treatment of SA for 3 weeks showed about 23~65% inhibition of photosynthetic activity at various light intensity (100~1000$\mu$mo1 m­$^2$S­$^1$). Similar effect was found on stomatal conductance. The treatment of SA caused an almost closure of stomata. Similar effects of stomatal conductance at various light intensity indicate a loss of normal control on stomatal mechanism. These results indicate that the effect of SA on photo-synthetic activity was not by SA itself but by indirect metabolic pathway.

• Journal of Life Science
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• v.27 no.7
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• pp.826-833
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• 2017

The rising concentration of atmospheric carbon dioxide is causing ocean acidification and global warming. The seahorse is an important species in marine ecosystems and fishery markets, however, their populations have recently decreased due to ocean acidification. As a result, we examined changes in the physiological responses of the spotted seahorse Hippocampus kuda when it was exposed to acidic sea water (pH 6.0, 6.5, and 7.0) and normal seawater (pH 8.0 as the control) over a period of 15 days. As the pH decreased, the seahorses' body weight and length also decreased. Components in body of ash, the crude lipids and crude proteins also differed significantly with changes in pH, due to stress caused by the seahorses' exposure to the acidic water conditions. The superoxide dismutase levels were significantly lower in the pH 6.0 and 6.5 groups than they were in the pH 7.0 and pH 8.0 groups. However, the catalase and glutathione levels were significantly higher in the acidic sea water groups. We suggest that decreasing the pH level of rearing water induces a stress response in H. kuda, damaging their ability to maintain their homeostasis and energy metabolism. Antioxidant enzymes are generally sensitive to acidic stress; in this study, the antioxidant activity was significantly affected by the pH level of the rearing water. These results indicate that physiological stress, induced by exposure to acidification, induces an antioxidant reaction, which can reduce general components in the body and the growth of H. kuda.

• Physical Therapy Korea
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• v.14 no.1
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• pp.46-54
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• 2007

The purposes of the present study were to determine the difference of functional outcome, and to identify factors associated with functional difference in patients with stroke. The sample consisted of 56 stroke patients who had received physical therapy at the physical therapy unit of the Dongeui Medical Center in Busan city between January 2000 and June 2002. Stroke patients were evaluated by physical therapists 3 times; The first day in physical therapy (PT) (T1), one month after the first day in PT (T2), and two months after the first day in PT (T3). Functional status was assessed with the Functional Independence Measure (FIM) instrument, a validated instrument for documenting the severity of disability and assessing the outcome of rehabilitation treatment. Functional gain was calculated over T2-T1, T3-T1, and T3-T2. SAS statistical software was used for the analysis. The Student's t-test, paired t-test, analysis of variance (ANOVA/Tukey and Scheffe), and analysis of covariance (ANCOVA) were used to examine the functional difference in variables. Repeated measures ANOVA was also used to analyze the functional difference by time (T1, T2, and T3). Multiple regression analysis was performed to determine the effects of independent variables on the difference of functional outcome as defined by the FIM score. A total of 56 stroke patients were evaluated, their average age${\pm}$standard deviation was $61.6{\pm}9.3$ years (range: 40~81 yr). The functional status of patients who received physical therapy for about 2~3 months was significantly improved (mean FIM scores, $20.5{\pm}1.8$, $28.9{\pm}1.9$, and $8.41{\pm}1.1$ points for each time period, respectively) (p<.0001). Diabetes was significantly associated with the FIM score for T2-T1 (p<.05). The type of diagnosis was significantly associated with the FIM score for T3-T1 (p<.05). Gender, smoking, and the FIM score on admission were significantly associated with the FIM score for T3-T2 (p<.05). In conclusion, gender, smoking, diabetes, the type of diagnosis, and the FIM score on admission were significantly associated with improved FIM scores. We recommend that further research should explore the functional outcome by using larger sample sizes, longer follow-up periods, and more sensitive assessment instruments.

• Korean Journal of Optics and Photonics
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• v.8 no.1
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• pp.31-36
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• 1997

We measured refractive indices and thicknesses of SiO$_2$ thin films that have been plated on LCD glass substrate for the purpose of preventing the out-diffusion of sodium ions. The best experimental condition to determine refractive index and thickness of SiO$_2$ thin film by using ellipsometry is searched for, where ⅰ) the film thickness is increased uniformly by 20 $\AA$ from 0 $\AA$ to the period thickness while the angle of incidence is fixed and ⅱ) the angle of incidence is increased uniformly by 1$^{\circ}$ from 45$^{\circ}$ to 70$^{\circ}$ while the film thickness is fixed. We estimated the errors in determining the refractive index and thickness by comparing the measurement error of $\Delta$ and Ψ with the calculated one. The ellipsometric constants of SiO$_2$ thin film on LCD glass substrate are measured at several angle of incidence around the Brewster angle, which is the best angle if the experimental error of ellipsometer is not sensitive to the incident angle. Also the best fit refractive index and thickness of SiO$_2$ thin film to these ellipsometric constants measured at several angle of incidenc eas well as the best fit ones to the SE data are obtained using regressional analysis.

• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.28-32
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• 2017

In this research, we designed an LSPR sensor based on a thin-film multilayer comprising $TiO_2$ and $SiO_2$. The thickness of the overall substrate layer of the suggested multilayer LSPR sensor is limited to 100 nm, and the number of repeating $TiO_2$ and $SiO_2$ thin films is 1-4 within a limited thickness. Additionally, a nanowire structure with a gold thin film of 40 nm, height of 40 nm, period of 600 nm, and line width of 300 nm was formed on the multilayer. To design the variable wavelength-type SPR, the angle was fixed at $75^{\circ}$ and the wavelength was changed. We then simulated the system with the finite-element method (FEM) using Maxwell's equations. It was confirmed that the resonance wavelength became shorter as the number of multilayers increased when the refractive index was fixed. We found that the wavelength changes were more sensitive. However, no changes were observed when the number of the multilayers was three or higher.

• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.191-196
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• 2011

In this study simple and sensitive high performance liquid chromatographic method using a commercially available column, was developed and validated for the determination of zolpidem tartrate in human plasma. The developed method with suitable validation was applied to a bioequivalence study of two different kinds of zolpidem tartrate. Two different formulations containing 10 mg of zolpidem tartate (CAS : 99294-93-6) were compared in 24 healthy male volunteers in order to compare the bioavailability and prove the bioequivalence. The study was performed in an open, single dose randomized, 2-sequence, cross-over design in 24 healthy male volunteers with a one-week washout period. Blood samples for pharmacokinetic profiling were drawn at selected times during 12 h. The mean $AUC_{0-12h}$, $C_{max}$, $T_{max}$ and $T_{1/2}$ were $676.6{\pm}223.4$ $ng{\cdot}h{\cdot}mL^{-1}$, $177.4{\pm}34.2$ $ng{\cdot}mL^{-1}$, and $0.8{\pm}0.4$ and $3.5{\pm}2.1$, respectively, for the test formulations, and $640.7{\pm}186.6$ $ng{\cdot}h{\cdot}mL^{-1}$, $193.0{\pm}64.5$ $ng{\cdot}mL^{-1}$, and $0.9{\pm}0.4$ and $2.7{\pm}0.9$, respectively, for the reference formulation. Both primary target parameters $AUC_{0-12h}$ and $C_{max}$ were log-transformed and tested parametrically by analysis of variance (ANOVA). 90% confidence intervals of $AUC_{0-12h}$ and $C_{max}$ were in the range of acceptable limits of bioequivalence (80-125%). Based on these results, the two formulations of zolpidem tartate are considered to be bioequivalent.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.4
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• pp.108-114
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• 1980

A deterministic conceptual erosion model which simulates detachment, entrainment, transport and deposition of eroded soil particles by rainfall impact and flowing water is presented. Both upland and channel phases of sediment yield are incorporated into the erosion model. The algorithms for the soil erosion and sedimentation processes including land and crop management effects are taken from the literature and then solved using a digital computer. The erosion model is used in conjunction with the modified Kentucky Watershed Model which simulates the hydrologic characteristics from watershed data. The two models are linked together by using the appropriate computer code. Calibrations for both the watershed and erosion model parameters are made by comparing the simulated results with actual field measurements in the Four Mile Creek watershed near Traer, Iowa using 1976 and 1977 water year data. Two water years, 1970 and 1978 are used as test years for model verification. There is good agreement between the mean daily simulated and recorded streamflow and between the simulated and recorded suspended sediment load except few partial differences. The following conclusions were drawn from the results after testing the watershed and erosion model. 1. The watershed and erosion model is a deterministic lumped parameter model, and is capable of simulating the daily mean streamflow and suspended sediment load within a 20 percent error, when the correct watershed and erosion parameters are supplied. 2. It is found that soil erosion is sensitive to errors in simulation of occurrence and intensity of precipitation and of overland flow. Therefore, representative precipitation data and a watershed model which provides an accurate simulation of soil moisture and resulting overland flow are essential for the accurate simulation of soil erosion and subsequent sediment transport prediction. 3. Erroneous prediction of snowmelt in terms of time and magnitute in conjunction with The frozen ground could be the reason for the poor simulation of streamflow as well as sediment yield in the snowmelt period. More elaborate and accurate snowmelt submodels will greatly improve accuracy. 4. Poor simulation results can be attributed to deficiencies in erosion model and to errors in the observed data such as the recorded daily streamflow and the sediment concentration. 5. Crop management and tillage operations are two major factors that have a great effect on soil erosion simulation. The erosion model attempts to evaluate the impact of crop management and tillage effects on sediment production. These effects on sediment yield appear to be somewhat equivalent to the effect of overland flow. 6. Application and testing of the watershed and erosion model on watersheds in a variety of regions with different soils and meteorological characteristics may be recommended to verify its general applicability and to detact the deficiencies of the model. Futhermore, by further modification and expansion with additional data, the watershed and erosion model developed through this study can be used as a planning tool for watershed management and for solving agricultural non-point pollution problems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.488-495
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• 1997

The effects of ammonia on survival and growth of the flounder larva, Paralichthys olivaceus, were examined by a static renewal bioassay method. The $96\;hr-LC_{50}$ with the developmental stages during the period from 1day to 23 day-old larvae ranged 0.273 to 1.023 mg $NH_3/\ell$. Tolerance of the larvae to ammonia toxicity was much sensitive at the early larval stage, and increased with the growth of the larvae. Threshold $96hr-LC_{50}$ in 1, 3 and S day-old larvae after hatching were 0.293, 0.248 and 0.379 mg $NH_3/\ell$, respectively. Survival rate and growth in body weight and body weight of the larva were reduced with increase of ammonia concentration in the range of 0.055 and 0.341 mg $NH_3/\ell$. The no-observable-effect concentration (NOEC) and lowest-observable- effect concentration (LOEC) of the flounder larve were 0.102 and 0.174 mg $NH_3/\ell$ for body length, and 0.151 and 0.198 mg $NH_3/\ell$ for body weight, respectively. Chronic value (ChV), which is the geometric mean of the NOEC and $NH_3/\ell$ to body length of the larvae were 0.124 mg $NH_3/\ell$. The coefficient of variation (CV) for body length was higher at high concentration than at low concentration.

• Journal of Ginseng Research
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• v.23 no.4
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• pp.230-234
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• 1999

Potassium channels play an important role in regulating vascular smooth muscle tone. Four types of $K^+$ channels areknown to be expressed in vascular smooth muscle cells, and maxi $Ca^{2+}-activated\;K^+$ channel $(BK_{Ca})$ is a dominant type of $K^+$ channels in these cells. Because total ginseng saponins and ginsenoside $Rg_3$ cause vasodilation with unclear mechanisms, we hypothesized that total ginseng saponins and ginsenoside $Rg_3$ induce vasodilation via activation of maxi $Ca^{2+}-activated\;K+$ channels. Whole-cell BKe. currents were voltage-dependent with half maximum activation at -14 mV, and the currents were sensitive to nanomolar ChTX and millimolar TEA. External application of total ginseng saponins increased the anlplitude of the whole-cell BKe. current in a concentration-dependent manner. Single-channel analysis indicates that total ginseng saponins caused the channel opening for a longer period of time. Ginsenoside $Rg_3$ increased the amplitude of whole-cell $K_{Ca}$ currents without affecting voltage dependence of the currents and increased single-channel open time. Hence, the results suggest that ginseng saponin-induced vasodilation may be due to activation of $K_{Ca}$.