• 한국지하수토양환경학회지:지하수토양환경
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• 제22권5호
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• pp.30-39
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• 2017

In this study, the predictive toxicity of barley Hordeum vulgare was estimated using a modified terrestrial biotic ligand model (TBLM) to account for the toxic effects of $CuOH^+$ and $CuCO_3(aq)$ generated at pH 7 or higher, and this was compared to that from the original TBLM. At pH values higher than 7, the difference in $EA_{50}\{Cu^{2+}\}$ (half maximal effective activity of $Cu^{2+}$) between the two models increased with increasing pH. As Mg concentration increased from 8.24 to 148 mg/L in the pH range of 5.5 to 8.5, the difference in $EA_{50}\{Cu^{2+}\}$ increased, and it reached its maximum at pH 8. The difference in $EC_{50}[Cu]_T$ (half maximal effective concentration of Cu) between the two models increased as dissolved organic carbon (DOC) concentration increased when pH was above 7. Thus, for soils with alkaline pH, the toxic effect of $CuOH^+$ and $CuCO_3(aq)$ are greater at higher salt and DOC concentrations. The acceptable Cu concentration in soil porewater can be estimated by the modified TBLM through deterministic method at pH levels higher than 7, while combination of TBLM and species sensitivity distribution through the probabilistic method could be utilized at pH levels lower than 7.

• Restorative Dentistry and Endodontics
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• 제40권4호
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• pp.270-275
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• 2015

Objectives: This study examined the color changes of a resin composite with different shades upon exposure to water with different pH. Materials and Methods: Nanohybrid resin composites (Filtek Z350XT, 3M ESPE) with four different shades (A2, A3, B1, and B2) were immersed in water with three different pH (pH 3, 6, and 9) for 14 day. The CIE $L^*a^*b^*$ color coordinates of the specimens were evaluated before and after immersion in the solutions. The color difference (${\Delta}E^*$) and the translucency parameter (TP) were calculated using the color coordinates. Results: ${\Delta}E^*$ ranged from 0.33 to 1.58, and the values were affected significantly by the pH. The specimens immersed in a pH 6 solution showed the highest ${\Delta}E^*$ values (0.87 - 1.58). The specimens with a B1 shade showed the lowest ${\Delta}E^*$ change compared to the other shades. TP ranged from 7.01 to 9.46 depending on the pH and resin shade. The TP difference between before and after immersion in the pH solutions was less than 1.0. Conclusions: The resulting change of color of the tested specimens did not appear to be clinically problematic because the color difference was < 1.6 in the acidic, neutral, and alkaline solutions regardless of the resin shade, i.e., the color change was imperceptible.

• 생명과학회지
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• 제14권4호
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• pp.573-576
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• 2004

The purpose of the present study is to investigate the lipid peroxidation, creatine kinase activity and cortisol hormone levels following the training intensity in elite judo players. Six elite Judo players participated in the experiments (3h repetition judo program), which include stretching, judo skill practice and cool down without recess. Blood sampling were taken at the judo gymnasium at the time of resting, 1h training, 2h training, 3h training, 2h recovery, and 24h recovery time and this were analyzed for CK, MDA and Cortisol levels. The results obtained were analyzed via repeated measures of ANOVA using SPSS package program (ver.10.0) and a value of p<.05 was considered statistically significant. The results from this study were as follows. In the CK levels, which reflect the contribution of creatine phosphate and muscle damage degree, there was a significant difference (p<.05) after judo training in every period. Recovery 24h showed the highest level. In the MDA levels, which reflect lipid peroxidation, there was a significant difference (p<.05) after judo training. Recovery 2h showed the lowest level. In the cortisol hormone levels, which reflect stress status, there was a significant difference (p<.05). In this study, we can conclude that For the trained athletes, MDA level was lower at the time of exercise compare to the other period, this is caused by the increased antioxidant defence mechanism.

• Journal of Preventive Medicine and Public Health
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• 제7권1호
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• pp.115-121
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• 1974

In order to evaluate the health hazard due to exposure to organophosphorus insecticides, we measured the blood cholinesterase activity ana urinary para-nitrophenol among 56 exposed subjects. They are orchard workers, rice plant workers and smithion factory workers. The clinical symptoms were also checked by physicians. We also measured the blood cholinesterase activity and urinary para-nitrophenol excretion of 20 urban people and 15 rural people who had never been exposed to organophosphorus insecticides in order to compare them according to age, sex and geographical differences. And these results were also compared with those of exposed groups. The results obtained were as follows. 1. The normal plasma cholinesterase activity and cell cholinestrase activity were $0.861{\pm}0.148\;{\Delta}pH/hr$ and $0.822{\pm}0.154\;{\Delta}pH/hr$. And normal para-nitrophenol in urine was $1.21{\pm}0.52mg/liter$. 2. No significant difference was existed in blood cholinesterase activities and urinary para-nitrophenol excre tion according to sex, age and geographical difference. 3. The plasma cholinesterase activity and cell cholinesterase activity of orchard workers, rice plant workers and smithion factory workers were $0.682{\pm}0.189\;{\Delta}pH/hr,\;0.775{\pm}0.160\;{\Delta}pH/hr,\;0.754{\pm}0.123\;{\Delta}pH/hr,\;and\;0.691{\pm}0.082\;{\Delta}pH/hr,\;0.756{\pm}0.117\;{\Delta}pH/hr,\;0.739{\pm}0.117\;{\Delta}pH/hr$. And significant decreses in blood cholinesterase activities were existed among orchard workers and smithion factory workers compared with control group. 4, The urinary para-nitrophenol excretions of orchard workers, rice plant workers and smithion factory workers were $1.33{\pm}0.66mg/liter,\;1.19{\pm}0.88mg/liter\;and\;1.37{\pm}0.67mg/liter$ and there were no significant difference between exposed groups and control group. 5. The clinical symptoms complained during and after organophosphorus insecticides exposure were frequently ranked by headache (67.7%) and vertigo (64.5%) and muscular ataxia and weakness (51.6%).

• Preventive Nutrition and Food Science
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• 제3권2호
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• pp.180-185
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• 1998

A regression equation was proposed for predicting protein digestibility using pH drop and free amino acid content. Results were compared with those determined by the pH drop method of Satterle et al. and with apparent in vivo digestibility in rats. Measurd free amino acid content prior to four enzyme digestion had an influence on calculating digestbiilty . Results from new equation correlated more highly (r=0.8434, difference average=2.304) with in vivo digestibility than the results of pH drop method (r=0.7603, difference average=10.099).

• Archives of Pharmacal Research
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• 제7권2호
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• pp.87-93
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• 1984

The effects of ionic strength and pH on the binding of cefazolin to bovine serum albumin (BSA) were studied by UV difference spectrophotometry. As ionic strength at constant pH and temperature increases, the apparent bining constant decreased but the number of binding sites remained almost constant at 2. The constancy of the number of binding sites with increasing the ionic strength suggests that purely electrostatic forces between BSA and drug do not have great importance in the drug binding, even though there is a decrease in the apparent binding constant. Thus, the effect of ionic strength on the interaction between drug and BSA may be explained by the changes in ionic atmosphere of the aggregated BSA molecules and competitive inhibition by phosphate ions. In addition, the higher apparent binding constant at high ionic strength is explained by conformational changes of BSA from its aggregate forms into subunits. The pH effects on the afinity of interactions indicated that the binding affinity of cefazoline is higher in the neutral region than in the alkaline region. An d at high pH value, the number of binding sites decreased from 2 to 1 because of the conformational change of BSA in the alkaline region.

• Clinical and Experimental Reproductive Medicine
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• 제10권1호
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• pp.39-43
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• 1983

During the period of Sep. 1981 to Feb. 1983, a program of measuring the blood gases and pH of 19 varicocele patients was taken. These patients were classified into 2 groups based upon their semen analyses; Group A consisted of 9 patients who demonstrated normal findings and group B consisted of 10 patients who demonstrated seminal stress pattern. The blood pH: $PO_2$ , and $PCO_2$ were measured in the internal spermatic vein and the radial vein of all the patients. The results obtained were as follows; 1. In Group A, no difference was detected in the value of the pH, $PO_2$ and $PCO_2$ between the internal spermatic vein and the radial vein. 2. In group B, a similar lack of difference in blood gases found between the internal spermatic vein and the radial vein. 3. The blood gases between the internal spermatic veins of Group A and B were compared. No difference was discovered between the 2 group also. It has been hypothesized that the pathogenesis of spermatogenic depression in patients with varicocele is testicular hypoxia due to low oxygen tension of the internal spermatic vein. However, our results do not bear out this proposed mechanism.

• 한국환경보건학회지
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• 제7권1호
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• pp.21-31
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• 1981

This survey was carried out to investigate the temperature, pH value, nitrogen (ammonia, nitrite, nitrate), turbidity, color, chloride ion, $KMnO_4$ consumed, and hardness as chemical analysis of the tap water in Seoul city area during the period from September to Octobor, 1979, and to observe the differences among the values by the distance from the water purification plant and by the district supplied tap water from-the each water purification plant. The results obtained were as follows: 1) An average of the water temperature was $19.8\pm 0.2\circ$C. 2) An average of pH was $7.18\pm 0.02$. The difference among each district was statistically significant (p<0.01), but it was not observed among each distance. 3) An average of turbidity was $1.25\pm 0.12$ ppm. The difference among each district was highly significant (p<0.01), respectively, but not among each distance. 4) An average of color was $1.43\pm 0.16$ ppm, and there were statistically significant differences by the distance and by the district (p<0.01). 5) An average of ammonia nitrogen was $0.022\pm 0.005$ ppm. The differences among each distance, and district were statistically significant (P<0.01). 6) An average of nitrite nitrogen was $0.0050\pm 0.0013$ ppm, and the difference among each distance was highly significant (p<0.01), respectively, and each district showed statistical significance (p<0.01). 7) An average of nitrate nitrogen was $0.82\pm 0.08$ ppm. The difference among each district was significant (p<0.05), and each distance showed high significance (p<0.01). 8) An average of $KMnO_4$ consumed was $3.73\pm 0.16$ ppm, and the difference among each district was significant (p<0.05), but it was not observed among each distance. 9) An average of chloride ion was $8.56\pm 0.28$ ppm, and the difference among each district was higly significant (p<0.01), respectively, but it was not observed among each distance. 10) An average of hardness was $40.69\pm 1.17$ ppm, and there was statistically significant difference by each district (P<0.01), but not by distance. 11) The interrelation between temperature and pH of the tap water revealed the negative correlation from the coefficient of it as showed r=-0.6073 and p<0.01. 12) Except water temperature, there were negative correlationships between pH and other water qualities. 13) Correlation coefficients of $KMnO_4$ comsumed and ammonia nitrogen, nitrite nitrogen were statistically significant but that of $KMnO_4$ consumed and nitrate nitrogen showed no statistical correlationship. 14) Ammonia nitrogen seems to have high correlationship with nitrite nitrogen(r= +0.6669), but not with nitrate nitrogen. 15) Nitrate nitrogen seems to have statistically significant correlationship with nitrite nitrogen (r=+0.4959), but not with ammonia nitrogen. 16) The interrelation between chloride ion and hardness of the tap water revealed positive correlation from the coefficient of it as showed as r=+0.4888 and p<0.01.

• The Korean Journal of Ecology
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• 제20권6호
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• pp.451-459
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• 1997

Seasonal and spatial distribution of vascular plants were examined and related to soil texture, pH, moisture and nutrient contents in the riparian zone of the Balan Stream. In spring the area was dominated by Alopecurus aequalis var. amurensis, was displaced by Persicaria thunbergii and Humulus japonicus in summer. From the stream channel to bank, soil texture and pH were not significantly differentiated, moisture decreased, organic matter and K increased, and TKN and available P increased in June and decreased in August. DCA ordination analysis by species distribution showed spatially and seasonally distinct patterns seasonal difference was evident on axis 1, and spatial difference according to the distance from stream channel was clear, too. Both axis 1 and axis 2 scores were significantly correlated with biomass, pH, and phosphate. Species richness increased were significantly correlated with biomass, pH, and phosphate. Species richness increaed with increasing organic matter and phosphate, and decreased with increasing soil moisture and K. Biomass increased with increasing organic matter, but was negatively related to pH, moisture, TKN, available P and K. Available P was significantly correlated with biomass, pH, and total soil nitrogen. In conclusion, the distribution of riparian vegetation was governed by soil physico-chemical properties, which are primarily determined by how far it is from the stream channel.

• Journal of information and communication convergence engineering
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• 제20권1호
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• pp.49-57
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• 2022

Fertilizers have long been used to increase crop yields; however, farmers are still having difficulties in managing fertilizers for growing crops as well as economic problems. The conventional method of soil sampling and laboratory analysis to determine soil pH is time consuming and costly; therefore, a portable pH sensor is developed to characterize spatial or temporal variability within fields via rapid and dense data acquisition. The portable pH sensor comprises an electrode unit, a portable console, and a USB connector. The soil water content (SWC) and electrical conductivity (EC) affect the electrical resistance of soil. An artificial test soil is performed to evaluate the effect of SWC and EC on soil pH. The test results show that stable pH measurements are achieved at SWCs greater than 20 mL (16.3%). Regardless of the SWC, the electric potential difference (EPD) remains at 2.5 g of NaCl. As the EC increases in the soil samples, the EPD increases.