• The Journal of Korean Physical Therapy
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• v.10 no.1
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• pp.1-6
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• 1998

The purpose of this study was to determine the of effective concentration of procaine iontophoresis for durarion of cutaneous local anesthesia. Forty-five healthy students with an age range of 19 to 34 years$(21\pm2.7)$, were participated in this study. The subjects were randomly assigned into 5 groups. Bach 9 subjects received iontophoresis on the flexor surface of dominant forearm with soft cotton pad $(3.5\times3.5cm)$ soaked in 2ml of $2\%$ (pH 5.28), $4\%$ (pH 5.12), $8\%$ (pH 4,98), $16\%$ (pH 4.72), $32\%$ (pH 4.52) procaine hydrochloride solution at 4mA for 10 minutes (total current 40mA min) using anodal direct current. The study was performed in a randomized, double-blind design, After procaine iontophoresis, the duration of anesthesia were evaluated at five minute intervals on five random locations in the iontophoretically area using a 21-gauge sterile hypodermic needle pressed with 1mm invagination unitl sharp pin-pricking pain sensation returned. The data were analyzed with one-way ANOVA to determine significant differences between groups. Duncan post hoc was performed at level .01. The relationship between anesthetic duration and procaine concentration was assessed with Pearson Product-Moment Correlation Coefficients. ANOVA tests showed significant differences in the anesthetic duration between the concentration of procaine solution (p<.001). Procaine iontophoresis with $4\%$ concentration produced cutaneous Socal anesthesia of significantly longer duration(15.56 min) than iontophoresis with $2\%,\;8\%,\;16\%$, and $32\%$ of procaine GCl(p<.01). Whereas the anesthetic duration had no correlation with concentration of procaine solution (r=-0.41, NS). These results support the $4\%$ procaine solution was an effective concentration of iontophoresis for induced cutaneous local anesthesia.

• Journal of the Korea Safety Management & Science
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• v.13 no.4
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• pp.109-116
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• 2011

This study examined into property of flour dust explosion to get the basic data for safety of industry by protecting accident of dust explosion. The experiment was conducted to know the effect of distance between explodes in the experiment device, effect of flour dust concentration, effect of humidity, effect of explosion pressure to the dust concentration and effect of inactive substance additive. The study indicated that explosion was happened effectively at the optimum distance 100mm or less in inter-polar distance, and minimum ignition energy was measured at 6mm. The data of feed concentration to the probability of explosion showed that the smaller the particle diameter was, the larger probability of explosion was, and the higher the dust concentration was, the more increased the pressure of explosion was, but more than upper limit of dust concentration, then the explosion of pressure decreased. For the effect of humidity, the more it contained water, the more decreased the ignition energy of dust was, so increased minimum explosive concentration, and effective water content was minimum 10% or more. Inactive substance additive was effective in adding more than 15% CaCO3 and CaO as substance inhibiting dust explosion, in which CaCO3 was more effective than CaO. the analysis of the flame of dust explosion was performed by high-speed video camera, it showed the size of flame bacame smaller in order that sub feed, main feed, wheat powder. As a result, sub feed was expected to be less dangerous than others.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.80-87
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• 2021

In this study, the toxic effects of PFOA and PFOS potassium salt on Mesocentrotus nudus using 10 min-fertilization rate and 48 h-normal embryogenesis were confirmed through the calculation of toxicity values such as Non-observed effective concentration, Low-observed effective concentration, and 50% of effective concentration. The case of 10 min-fertilization rate and 48 h-normal embryogenesis showed the concentration-dependent reduction pattern when exposed to PFOA and PFOS potassium salt, in tested concentration, respectively. The EC50 values of 10 min-fertilization rates for PFOA and PFOS potassium salt were 1346.43 mg/l and 536.18 mg/l, respectively, and the EC50 values of 48 h-normal embryogenesis were 42.67 mg/l and 17.81 mg/l, respectively. Both toxicity test methods showed high toxicity sensitivity to PFOS potassium salt. Recent studies have shown that the concentration of PFOA and PFOS in the marine environment has continuously decreased, and it is not enough to show acute toxicity to sea urchin. However, PFOA and PFOS have a very long half-life and can accumulate throughout the life of marine life, so it is still observed at a high concentration in shellfish. Therefore, a study on chronic toxicity through the whole-life cycle of marine organisms in coastal environments should be needed.

• Food Science of Animal Resources
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• v.20 no.1
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• pp.36-43
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• 2000

$\beta$-cyclodextrin adsorption and saponification methods were applied to isolate and purify cholesterol from the by-product of the low-cholesterol egg yolk product. They by-product was prepared from processing low-cholesterol egg yolk followed by extracting with chloroform to remove $\beta$-cyclodextrin and concentrated to 3,069 mg% cholesterol. When $\beta$-cyclodextrin method between two purification methods was applied, 50% ethanol as a solvent showed higher cholesterol concentration of 5.82% rather than the other solvents. Repeated purification of 3 times could not improve the cholesterol concentration significantly(p<0.05). In case of purification using saponification method, hexane as a solvent for extraction of unsaponificated materials was more efficient to increase cholesterol concentration than chloroform and ether. 60 times(v/w) saponification solution (95% ethanol:33% KOH = 94:6) of sample weight was most effective to increase the cholesterol concentration of 35.7%. Repeated purification process by saponification method could increase cholesterol concentration to 95.7% by 4 times repetition.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.669-675
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• 2003

Using a SQUID magnetometer, the diamagnetic susceptibility of NaCl aqueous solution was measured with high accuracy in a magnetic field of up to 6 Tat 25$\pm0.05^{\circ}C$. The NaCl concentrations adopted in this experiment were 0 (water), 7.5, 15, 23, 26.2, 26.6 and 100% (crystal) with the concentration error of $\pm$0.04%. Experimental data was compared with the calculated value of susceptibility derived from dependence of the vapor pressure on NaCl concentration As a result, our measured value was almost in accordance with the calculated value. It was found that the diamagnetic susceptibility shows a decrease of approximately 10% within the saturated concentration (26.2%) and that the susceptibility is one of the effective cause for the concentration dependence in the gas-liquid interface deformation of the NaCl solution.

• Transactions on Electrical and Electronic Materials
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• v.5 no.4
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• pp.161-165
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• 2004

In order to get oxidizing power enough for growth of a superconductive thin film with oxide gas, concentrated ozone was used. As a method for concentrating ozone, a method for concentrating ozone by adsorbing ozone selectively into silica-gel beads is adopted, and this concentration is analyzed by the ultraviolet absorption method, the thermal decomposition method and the Q-mass analyzing method. Thermal decomposition method is most effective for measurement of a high concentration of ozone. Ozone as concentrated by the adsorption method got to have a concentration of 97 mol % at the maximum, and it was identified that the concentration of the ozone gas was stable for the time while a thin film was formed.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.261-267
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• 2010

The variation of assimilable organic carbon(AOC) concentration at each condition of ozonation was investigated using a model water and drinking water resource. AOC concentration of model raw water and drinking water resource tended to increase at low ozone dose. The maximum AOC concentration was detected when the residual ozone begin to be measured. Also, the AOC concentration increase at pH 8 compared to both pH 6 and 7 while that for pH 9 decreased rapidly. The removal characteristics of trihalomethane formation potential(THMFP) by ozonation was also investigated. Unlike the trend of AOC, the THMFP concentration never increased by ozonation but decreased even at low ozone dosage. From these results, the ozone dosage would be effective to simultaneously decrease both AOC and THMFP.

• Journal of Pharmaceutical Investigation
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• v.12 no.2
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• pp.31-36
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• 1982

The effect of some surfactants, such as tween 40, tween 80, span 80, and triethanolamine, on the absorption of lidocaine was studied using goldfish as a model of absorption kinetics. This model was believed that reciprocal overturn time and death time were the occurrence of biological effect versus drug absorption. The results were as follows; The threshold concentration of lidocaine was significantly reduced by the surfactants. Overturn time and death time of goldfish in the lidocaine solution were reduced by such surfactants as tween 40, tween 80, span 80 and triethanolamine, and more reduced with increasing concentration of surfactants except tween 40 and tween 80. The plots of reciprocal death time versus lidocaine concentration were linear relationship with a positive concentration intercept such as minimum effective concentration (0.2-0.8%). As results it is believed that these surfactants may form complexes with lidocaine or affect the goldfish membrane to make more permeable to lidocaine, which is adsorbed more rapidly.

• Journal of Pharmaceutical Investigation
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• v.12 no.1
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• pp.23-30
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• 1982

The effect of various surfactants on the absorption of antipyrine was studied using goldfish and rat. The results are as follows. The threshold concentration of antipyrine was reduced by various surfactants. Overturn time and death time of goldfish, in solution containing different concentration of antipyrine was reduced by the presence of various surfactants. Plots of reciprocal death time versus antipyrine concentration were linear with a positive concentration intercept such as minimum effective concentration. The absorption of antipyrine from rat small intestine was increased by administration with surfactants. As results, is believed to be one of rendering the goldfish membrane or rat small intestine more permeable to antipyrine.

• Applied Science and Convergence Technology
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• v.23 no.1
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• pp.27-33
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• 2014

We have studied photovoltaic characteristics of single-junction GaAs solar cells with/without an $MgF_2/ZnS$ anti-reflective coating (ARC) illuminated by low-density concentration (<10 suns). By the ARC deposition, the short-circuit current density ($J_{SC}$) and the fill factor (FF) are increased by $5mA/cm^2$ and 5% at a standard illumination (1 sun), respectively, and the resulted conversion efficiency is enhanced by 45%. In contrast with the cell with no ARC showing a rapid degradation with increasing concentration power, the efficiency of ARC-deposited cell remains almost constant as ($17.7{\pm}0.3$)% regardless of the concentration. It informs that ARC treatment is very effective in GaAs concentrator solar cells.