• Resources Recycling
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• v.13 no.4
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• pp.11-16
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• 2004

In this study, treatment conditions for monazite concentrate in Hong-Cheon area deposit were studied with NaOH fritting decomposition and HCl leaching experiments. At condition of NaOH fritting decomposition, it was appropriate to adopt particle size of -200 mesh monazite, reaction temperature of about $460^{\circ}C$ and NaOH/TREO mole ratio of 6. In case of HCl leaching for decomposed product, it was appropriate to use hydrochloric acid of above 8N with leaching temperature of above $80^{\circ}C$, leaching time of 2 hrs and pulp density of about 10%. A rate of decomposition and leaching for monazite was above 90% under optimum conditions. Sodium phosphate compound was effectively recovered from NaOH decomposed solution, and mixed rare earth chloride solution was prepared with HCl leaching of decomposed product.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.111-116
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• 1996

Polyphenol oxidase(PPO) isolated from the crude extract of ascidian, Halocynthia roretzi, showed higher affinity for catechol than tyrosine or DL-DOPA. Successful enzyme assay could be performed at $25^{\circ}C$, 10min. by mixing 0.2ml of crude enzyme extract with 2.8ml of 0.13M catechol in 0.1M sodium phosphate buffer(pH 6.4). The specific activity of PPO which had been purified with a combination of ammonium sulfate treatment, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sepharose 6B was 13-fold disc gel electrophoresis. The activity of PPO was stable from pH 5.0 to 8.0 and showed the peak activity at pH 6.4 .The optimum reaction temperature for PPO oxidation on catechol was 35$^{\circ}C$ and those enzyme were heat stable up to 4$0^{\circ}C$. Molecular weigth of the enzyme was estimated about 170kDa. One molecule was found to be composed of gour subunits. Two of them had molecular weigh of 55kDa and the others 30kDa. The {TEX}$K_{m}${/TEX} values, {TEX}$V_{max}${/TEX} and catalytic efficiency({TEX}$V_{max}${/TEX}/{TEX}$K_{m}${/TEX}) for catechol were 0.12mM, 2.5mM/liter/min. and {TEX}$0.18min^{-1}${/TEX} respectively. The substrate affinity and electrophorectic pattern suggested that the enzyme of ascidian was considered to be not tyosine but catechol oxidase.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.3
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• pp.220-230
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• 2018

Purpose: This study was a cross-sectional study comparing differences in self-management knowledge, self-management, physiologic indexes, and symptoms experience for two methods of dialysis. Methods: Participants were 90 patients on hemodialysis and 91 on peritoneal dialysis at A hospital. Results: There was no significant difference between the two groups for knowledge of self-management. A comparison of the categories in the evaluation of self-management showed that patients in the peritoneal dialysis group took better care of their dialysis access route (F=17.61, p<.001) and dialysis schedule (F=4.30, p=.040). The physiologic indexes between the two dialysis groups showed that hemoglobin levels were higher in the hemodialysis group (F=5.28, p=.023). The product of serum calcium and phosphate was higher in the peritoneal dialysis group (F=11.42, p=.001). Serum sodium level was also higher in the peritoneal dialysis group (t=5.36, p<.001) while serum albumin level (t=-3.36, p=.001) and mean arterial blood pressure (t=-2.50, p=.013) were higher in hemodialysis patients. There were no significant differences in the proportion of uncomfortable experiences between the two groups. Conclusion: Medical personnel should consider differences in self-management knowledge/self-management, physiologic indexes, and symptoms experience for hemodialysis and peritoneal dialysis populations, and should provide adequate education accordingly and promote behavioral change to improve physiologic indexes and reduce symptoms.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.2
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• pp.105-110
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• 2021

Objective: Uropathogenic Escherichia coli is known to cause urinary tract infections, and the endotoxin (lipopolysaccharide [LPS]) of this bacterium may cause deficiencies of sperm quality and morphology. In the present study, the effects of LPS on mouse sperm were studied, and the levels of interleukin (IL)-17A and possible changes in testis tissue were evaluated. Methods: LPS of uropathogenic E. coli was extracted using the methanol-chloroform method, followed confirmation using sodium dodecyl sulfate-polyacrylamide electrophoresis. Purified LPS (100 ㎍/kg) or phosphate-buffered saline was injected intraperitoneally into BALB/c mice for 7 days consecutively in the test and control groups, mice were sacrificed on days 3, 7, and 42 after the first injection. Blood was tested for levels of IL-17A using the enzyme-linked immunosorbent assay method. Testis tissue and sperm were collected from each mouse and were studied according to standard protocols. Results: The mean sperm count and motility significantly decreased (p=0.03) at 3, 7, and 42 days after the injections. The level of IL-17A in the test groups increased, but not significantly (p=0.8, p=0.11, and p=0.15, respectively). Microscopic studies showed no obvious changes in the morphology of the testis tissue; however, significant changes were observed in the cellular parenchyma on day 42. Conclusion: LPS can stimulate the immune system to produce proinflammatory cytokines, resulting in an immune response in the testis and ultimately leading to deficiency in sperm parameters and testis tissue damage. In addition, the presence of LPS could significantly impair sperm parameters, as shown by the finding of decreased motility.

• Journal of Soil and Groundwater Environment
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• v.26 no.1
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• pp.65-75
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• 2021

We investigated hydrochemical and stable isotope characteristics of groundwater in a large agricultural plain, the Honam plain, to evaluate the adequacy of agricultural water supply. For preliminary assessment for the area, we collected 23 groundwater samples from domestic wells and conducted hydrochemical and water stable isotope analysis. Groundwater in the study area is mainly Ca-HCO3 type resulting from water-rock interactions. Stable oxygen and hydrogen isotopic compositions indicated that recharge water is derived from precipitation while some sampling sites had evaporation signatures. Irrigation water quality using sodium absorption ratio and salinity hazard showed most of the groundwater samples were found to be suitable for irrigation. The groundwater in the southwestern part of the study area was affected by both seawater intrusion and agricultural activities, indicating a higher possibility of groundwater contamination near the coastal areas. Elevated concentrations of nitrate and phosphate ions in the groundwater are considered to be influenced by anthropogenic activities such as fertilizer application. It is expected that this study would be able to provide preliminary information on groundwater quality for agricultural water supply in the Mangyeong-Dongjin watershed.

• Parasites, Hosts and Diseases
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• v.60 no.5
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• pp.345-352
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• 2022

Chitinase AO-801 is a hydrolase secreted by Arthrobotrys oligospora during nematode feeding, while its role remained elusive. This study analyzed the molecular characteristics of recombinant chitinase of Arthrobotrys oligospora (reAO-801). AO-801 belongs to the typical glycoside hydrolase 18 family with conserved chitinase sequence and tertiary structure of (α/β)₈ triose-phosphate isomerase (TIM) barrel. The molecular weight of reAO-801 was 42 kDa. reAO-801 effectively degraded colloidal and powdered chitin, egg lysate, and stage I larval lysate of Caenorhabditis elegans. The activity of reAO-801 reached its peak at 40℃ and pH values between 4-7. Enzyme activity was inhibited by Zn2⁺, Ca2⁺, and Fe3⁺, whereas Mg2⁺ and K⁺ potentiated its activity. In addition, urea, sodium dodecyl sulfate, and 2-mercaptoethanol significantly inhibited enzyme activity. reAO-801 showed complete nematicidal activity against C. elegans stage I larvae. reAO-801 broke down the C. elegans egg shells, causing them to die or die prematurely by hatching the eggs. It also invoked degradation of Haemonchus contortus eggs, resulting in apparent changes in the morphological structure. This study demonstrated the cytotoxic effect of reAO-801, which laid the foundation for further dissecting the mechanism of nematode infestation by A. oligospora.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.78.1-78.13
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• 2022

Background: Florfenicol might be ineffective for treating Staphylococcus aureus small colony variants (SCVs) mastitis. Objectives: In this study, florfenicol-loaded chitosan (CS)-sodium tripolyphosphate (TPP) composite nanogels were prepared to allow targeted delivery to SCV infected sites. Methods: The formulation screening, the characteristics, in vitro release, antibacterial activity, therapeutic efficacy, and biosafety of the florfenicol composite nanogels were studied. Results: The optimized formulation was obtained when the CS and TPP were 10 and 5 mg/mL, respectively. The encapsulation efficiency, loading capacity, size, polydispersity index, and zeta potential of the optimized florfenicol composite nanogels were 87.3% ± 2.7%, 5.8% ± 1.4%, 280.3 ± 1.5 nm, 0.15 ± 0.03, and 36.3 ± 1.4 mv, respectively. Optical and scanning electron microscopy showed that spherical particles with a relatively uniform distribution and drugs might be incorporated in cross-linked polymeric networks. The in vitro release study showed that the florfenicol composite nanogels exhibited a biphasic pattern with the sustained release of 72.2% ± 1.8% at 48 h in pH 5.5 phosphate-buffered saline. The minimal inhibitory concentrations of commercial florfenicol solution and florfenicol composite nanogels against SCVs were 1 and 0.25 ㎍/mL, respectively. The time-killing curves and live-dead bacterial staining showed that the florfenicol composite nanogels were concentration-dependent. Furthermore, the florfenicol composite nanogels displayed good therapeutic efficacy against SCVs mastitis. Biological safety studies showed that the florfenicol composite nanogels might be a biocompatible preparation because of their non-toxic effects on the renal tissue and liver. Conclusions: Florfenicol composite nanogels might improve the treatment of SCV infections.

• Journal of Radiation Protection and Research
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• v.48 no.2
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• pp.77-83
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• 2023

Background: The purpose of this study is to purify uranium (U[VI])-contaminated soil-flushing effluent using the precipitation-distillation process for clearance. Precipitation and distillation are commonly used techniques for water treatment. We propose using a combination of these methods for the simple and effective removal of U(VI) ions from soil-flushing effluents. In addition, the U concentration (Bq/g) of solid waste generated in the proposed treatment process was analyzed to confirm whether it satisfies the clearance level. Materials and Methods: Uranium-contaminated soil was decontaminated by soil-flushing using 0.5 M sulfuric acid. The soil-flushing effluent was treated with sodium hydroxide powder to precipitate U(VI) ions, and the remaining U(VI) ions were removed by phosphate addition. The effluent from which U(VI) ions were removed was distilled for reuse as a soil-flushing eluent. Results and Discussion: The purification method using the precipitation-distillation process proposed in this study effectively removes U(VI) ions from U-contaminated soil-flushing effluent. In addition, most of the solid waste generated in the purification process satisfied the clearance level. Conclusion: The proposed purification process is considered to have potential as a soil-flushing effluent treatment method to reduce the amount of radioactive waste generated.

• Analytical Science and Technology
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• v.36 no.1
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• pp.32-43
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• 2023

This study reports for the first time about a stability indicating RP-HPLC method for qualitative and quantitative determination of acalabrutinib in bulk and dosage form and in presence its impurities 1, 2 and 3. The chromatographic separation was carried on Zorbax XDB-C18 (250×4.6 mm; 5 µ id) as stationary phase, Phosphate buffer pH 6.4 and methanol 80:20 (v/v) as mobile phase at a flow rate of 1.0 mL/min, UV detection was carried at wavelength of 238 nm and the analysis was completed with a run time of 15 min. In these conditions the retention time of acalabrutinib and its impurities 1, 2 and 3 was observed to be 3.50, 4.83, 8.40 and 9.93 min respectively. The method was validated for system suitability, range of analysis, precision, specificity, stability and robustness. Spiked recovery at 50 %, 100 % and 150 % was carried for both standard and impurities and the acceptable % recovery of 98-102 was observed for acalabrutinib and both impurities studied and the % RSD in each spiked level was found to be less than 2. Stability tests were done through exposure of the analyte solution to five different stress conditions i.e expose to 1N hydrochloric acid, 1 N sodium hydroxide, 3 % peroxide, 80 ℃ temperature and UV radiation at 254 nm. In all the degradation condition, standard drug acalabrutinib was detected along with both the impurities studied and the degradation products were successfully separated. In the formulation analysis there is no other chromatographic detection of other impurities and formulation excipients. Hence the developed method was found to be suitable for the quantification of acalabrutinib and can separate and analyse impurities 1 and 2.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.596-602
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• 2023

Chromium-based metal-organic frameworks (MIL-101(Cr)) were synthesized, and their potential use as a filling material for gas masks or protective clothing was assessed through adsorption experiments using diisopropyl methyl phosphate (DIMP) as a simulant for chemical warfare agents. MIL-101(Cr) was prepared using acetic acid (MIL-101(Cr)-A) and sodium hydroxide (MIL-101(Cr)-N) as modulators. The use of acetic acid as a modulator resulted in a larger specific surface area and a higher DIMP adsorption capacity. MIL-101(Cr)-A absorbed approximately 160% of its own weight of moisture when exposed to an environment with a relative humidity of 90% for 10 days, surpassing other adsorbents such as activated carbon. The DIMP adsorption capacity of MIL-101(Cr)-A decreased to about 40% of its initial adsorption capacity after 24 hours of exposure to an environment with a relative humidity of 90%. However, this capacity is still higher compared to that of activated carbon used in commercial gas masks, suggesting a high potential for future use as a filling material for gas masks or protective clothing.