• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.597-603
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• 1996

This study was carried out to examine degradation characteristics of microalgae Chlorella vulgaris in methane fermentation. We measured COD and VS reduction, gas and methane productivity, VFA (volatile fatty acid), respectively. Then we calculated material balance and hydrolysis rates in soluble and solid material. The substrate concentration was controlled from 14 gCOD$_{cr}$/l to 64 gCOD$_{cr}$/l in batch cultures, and HRT (hydraulic retention time) controlled from 2 days to 30 days in continuous experi- ments. The results were as follows. In batch culture, accumulated gas productivity increased with the increase of the substrate concentration. The SS and VSS was removed all about 30% increase of substrate concentration and the most of the degradable material removed during the first 10 days. The curve of gas and methane production rate straightly increased until substrate concentration is 26 gCOD$_{cr}$/l. In continuous culture experiments, the removal rates at HRT 10days were 20% for total COD and TOC, respectively. At longer HRT, there was no increase in the removal efficiency. At HRT 15 days, the removal rates were 30% for SS and VSS, respectively. Soluble organic materials were rapidly degraded, and so there was no accumulated. Soluble COD concentration was not increase regardless of HRT-increasing. That meaned the hydrolysis was one of the rate-limiting stage of methane fermentation. The first-order rate constants of hydrolysis were 0.23-0.28 day$^{-1}$ for VSS, and 0.07-0.08 day$^{-1}$ for COD.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.17-21
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• 1993

Characteristics of a downflow anaerobic packed bed reactor with raschig ring ceramics as a packing were measured and discussed for the basic evaluation of the process. A synthesized glucose substrate wastewater were used as a feed and process characteristics such as pH, biogas production, composition of produced gas, COD removal and VSS were measured with the hydraulic retention time (HRT) changing from 0.25 to 2 days. As a result, this type of reactor was applicable in continuous operation within the given HRT range and the transient period approaching the steady state was about 20 days. The content of methane in produced gas increase with HRT was always high above 50% enough to use as energy source. The COD removal efficiency increased gradually as HRT increased. The axial profile of VSS concentration in the reactor usually showed the maximum at the lower region and the minimum at the middle. The VSS concentration at the upper region and the exit appeared similarly. However, at 0.25 day of HRT, the VSS concentration of effluent became higher than that of the upper region. Therefore the optimum HRT of this reactor occurred about 0.5 day, at which the production of methane began to be just stabilized and loss of VSS and COD removal were resonable.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.18 no.3
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• pp.317-327
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• 2011

Purpose: The purpose of this study was to contribute data toward prevention from advancing dementia and also prevention of deterioration in cognitive impairment by constructing an optimal prediction model and verifying factors influencing cognitive impairment in elders with dementia who reside at home. Methods: The participants in this study were 351 elders who were registered at dementia day care centers in 11 regions of Metropolitan Incheon. Collected data were analyzed using SPSS Statistics 17.0 and SAS 9.1. Bootstrap method using the Clementine program 12.0 was applied to build an optimum prediction model. Results: Gender and education (general characteristics), alcohol, urinary/fecal incontinence, exercise, weight, and ADL (state of health), and depression (psychological state) were found to have an affect on cognitive impairment in these elders. Conclusion: Study results indicate nine key factors that affect cognitive impairment of elders with dementia who reside at home and that could be useful in prevention and management nursing plans. These factors could also be used to expand the role of nurses who are working in community day care centers, and can be applied in the development and provision of various programs to aid retention and improve cognitive function as well as preventing deterioration of cognition.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.349-356
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• 2023

Garlic powder (GP) was supplemented in the diet to assess the growth efficiency, nutritional retention, and fecal score of growing pigs. In total, 80 growing pigs ([Yorkshire × Landrace] × Duroc) were arbitrarily allotted (22.04 ± 0.56 kg primary average body weight) to two different trial groups with eight repetitions (three males and two females) in each pen for the 42-day trial. The dietary treatment consisted of control (CON, basal diet), which included 0.2% GP (TRT1). Growing pigs fed the GP diet exhibited an increase (p < 0.05) in body weight on day 42 and a lower (p < 0.05) overall feed conversion ratio compared to the CON pigs; however, the average daily gain and feed intake showed no difference (p > 0.05). Additionally, nutrient utilization of dry matter was greater (p < 0.05) in the GP-supplemented diet group than in the CON group. The feeding methods did not adversely affect the nitrogen and energy utilization and the fecal score significantly (p > 0.05). In summary, growing pigs fed the GP diet showed increased growth and nutritional utilization, and no adverse impact on the fecal score; thus, it could be utilized as a stimulant for improved growth performance.

• Journal of Preventive Medicine and Public Health
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• v.30 no.1 s.56
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• pp.171-179
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• 1997

This study was performed to see whether neurobehavioral tests was affected by the exposure-free time in the workers chronically exposed to organic solvents. Thirty-four female workers were participated and four items among neurobehavioral core test battery of World Health Organization, including digit span, Santa Ana Dexterity, digit symbol and Benton Visual Retention, were administered to the workers. Test was conducted three times-preshift on Monday, preshift on Weekday and during shift on Weekday-per person and the interval of tests was 2 weeks. Digit span forward, Santa Ana Dexterity, digit symbol, and Benton Visual Retention showed significant decrements by performing time, especially during shift on Week-day versus preshift on Monday and preshift on Weekday. In addition, the score at preshift on Weekday was significantly lower than preshift on Monday, in preferred Santa Ana Dexterity and digit symbol. Generally, those who were exposed to high concentration, over 50 years and under 6 years of education showed marked decrease of score at during shift. So, it would be desirable that neurobehavioral test is conducted at preshift on Monday and items related to short term memory could be considerable to be done at preshift on Weekday.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.671-675
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• 1992

This experiment was carried out to establish a proper method of indocyanine green(ICG) excretion test for a applicable liver function test in dogs. The half life(T1/2), fractional clearance rate(KICG) and retention rate after injection of ICG with or without administred carbon tetrachloride($CCl_4$) were also invested. The results obtained were as follows ; 1. The maximum absorbance of ICG in plasma was at 810nm. 2. Half life and fractional clearance rate when administered 0.25 and 0.50mg of ICG per Kilogram body weight were $6.33{\pm}0.58$ minutes and $0.11{\pm}0.99$/minute in the former, $10.01{\pm}1.0$ minutes and $0.07{\pm}0.007$/minute in the latter, respectively. The ICG removal rate was exponentially linear for the first 15 minutes after injection both, of 0.25 and 0.50mg of ICG. 3. One day following the administration of $0.0042m{\ell}\;CCl_4$ kilogram body weight which injected 0.50mg of ICG, half life was more longer and fractional clearance rate was significantly reduced than that of ICG single injection. 4. Plasma retention rate when 15, 30, 45 minutes after injection dose of 0.25 and 0.50mg ICG per Kilogram body weight, $14.7{\pm}4.8$, $5.1{\pm}3.1$, $2.6{\pm}1.6%$ in the former, $26.9{\pm}1.8$, $11.1{\pm}2.4$, $4.8{\pm}1.3%$ in the latter, respectively. However, after administration of $CCl_4$, plasma retention rate of ICG at a dose of 0.50mg, it was $39.3{\pm}0.9$, $16{\pm}2.9$, $10.7{\pm}0.1%$, respectively. 5. Plasma enzyme(AST, ALT, r-GTP) activities administered with $CCl_4$ were increased, but there was no change which injected any dose of single ICG injection. From these results, ICG excretion test to dog is applicable to evaluation of liver function in both clinical and research.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.81-86
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• 1980

This experiment was carried out to evaluate the effect on different levels of crude protein intake according to sex and body weight on the nitrogen retention, and the protein requirement for feeding standard of the Korean Native Goat. The results obtained from the study were as follows. 1. The nitrogen retention rate when the female goat at 6 months age (13kg) had taken native grass hay 40%(126g) and flaking barley 60%(186g) was 36 percent, and when the intake matter was native grass hay 55%(226g) and flaking barley 45%(186g) was 25.6 percent. 2. The nitrogen retention rate when the meal goat at 5 months age (11kg) had taken native grass hay 47%(245g), flaking barley 29%(153g) and soybean meal 24%(126g) was 52.4 percent and when the intake was native grass hay 42%(206g) and flaking barley 58%(279g) was 40.7 percent. But if the in take matter was only (328g) native grass hay (crude protein 8%) it was -23.9 percent. 3. Maintenance nitrogen requirement of Korean native goat were estimated about 5g per day to 11 or 13kg live weight.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.255-261
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• 2005

The purpose of this study is to compare hepatotoxicity of each treatment for dermatophytosis; one is the administration of the ketoconazole only and the other, ketoconazole with diphenyl-dimeththyl-dicarboxylate. Have chosen the range of 14-24 months of healthy dogs divided by two groups (group 1 and group 2) for the experiment of which test proved positive in dermatophytosis diagnosis and showed normal reaction in terms of physical examination, blood chemistry and especially of liver function. Group 1 was administrated ketoconazole orally at 10 mg/kg/day and of same dose of ketoconazole with diphenyl-dimethyl-dicarboxylate for group 2. After administering, we have tested two groups by blood collecting every one week in order to check the differences of hepatotoxicity state through AST, ALT and r-GTP, the barometers of liver function which lasted for 12 weeks. Moreover, tested Indocyanine Green (ICG), known as susceptible gauge of function of excretion before starting the experiment and tested ICG as well after 12 weeks. The experiment of result the value of group 1 in AST, ALT and r-GTP has been highly rised after administering ketoconazole for 10 weeks meanwhile, of group 2 has shown a steady state troughout the whole experiment. For ICG test, we injected 0.5 mg/kg of ICG into a vein for both groups and tested the retention rate at regular interval of 15, 30, 45 minutes. The results of retention rate in two groups were similar to before the drug administration. However, after 12 weeks the retention rate of group 1 has been delayed, on the other hand, retention rate of group 2 were a steady state. In conclusion, the administration of ketoconazole only for a long period of time induced hepatotoxicity where as, the administration of ketoconazole with diphenyl-dimethyl-dicarboxylate didn't induce hepatotoxicity. Therefore, when doctors prescribes for a dog with dermatophytosis should not administrate ketoconnazole itself but with diphenyl-dimethyl-dicarboxylate and one who has abnormal condition of liver function should not be prescribed ketoconazole treatment. If there is a case needed to prescribe ketoconazole treatment, the regular monitoring should be accompanied by at the same time.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.390-397
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• 2018

The Municipal Wastewater Treatment Plant(MWTP), located industrial estate, has a problem of decreasing nitrification efficiency. In this research, it was analyzed that effect of heavy metals and retention time to nitrification based on operational result of laboratory scale reactors. And suggest improving MWTP operation method for increasing nitrification efficiency based on findings. According to operational result, laboratory scale reactor shows over 60% nitrification efficiency over hydraulic retention time(HRT) 0.5 day. However, the nitrification efficiency of S MWTP(high heavy metal concentration) sample was lower than that of A MWTP(low heavy metal concentration) sample in same operational condition. The main reason was heavy metals in industrial wastewater. This heavy metals was acted as inhibitor to nitrifier in reactors. So, activity of nitrifier was analyzed based on specific nitrification rate(SNR). The SNR of S MWTP sample shows 0.13 ~ 0.21 mg NH4/gMLSS/hr and that of A MWTP sample shows 0.74 mg NH4/gMLSS/hr. As a result, the activity of nitrifier of S MWTP was lower than that of A MWPT. In other words, retrofit methods for improving nitrification efficiency in MWTPs located industrial estate were that to increase retention time in biological treatment process or to pretreat heavy metal before being injected biological treatment process.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.783-792
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• 2007

To investigate the effects of alkalinity on the nitrification capability of the nonwoven fabric filter bioreactor(NFBR), an experiment was performed for 641 days at a hydraulic retention time of approximately 11 hours by changing the influent concentration of $NH_3-N$ from 54 mg/L to 1,400 mg/L and alkalinity from 43 mg/L to 10,480 mg/L. The MLSS concentration reduced from an initial value of 2,650 mg/L down to 830 mg/L, then increased up to 8,340 mg/L. Though the volumetric loading rate varied in a range of $0.120\sim3.130$ kg $NH_3-N/m^3-day$, the F/M ratio showed a narrow range of $0.067\sim0.414$ kg $NH_3-N/kg$ MLSS-day. The average nitrification efficiency at each experimental stage resulted in the range of $35.2\sim100%$, and the maximum nitrification rate was 2.970 kg $N/m^3-day$ or 0.489 g N/g MLVSS-day. The nitrifiers' fraction of the MLVSS increased up to 100% from an initial value of 7.1% and the biofilm formed on the nonwoven fabric filter showed a very low nitrifiers' fraction of mere 2.2%. The growth yield of the MLSS and the alkalinity consumption rate were computed to be 0.117 g VSS/g N removed and 7.08 g alkalinity/g $NO_x^--N$ produced, respectively. Results of the research suggest that NFBR could be an adequate process for nitrification of wastewaters with high ammonia concentrations.