• Applied Chemistry
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• v.15 no.1
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• pp.25-28
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• 2011

A highly sensitive spectrofluorimetric method was developed for the determination of levodopa based on the formation of a ternary complex with Eu³⁺ in the presence of ethylenediaminetetraacetic acid. It was found that this complex manifests intense fluorescence at 591 and 613 nm with excitation at 372 nm and maximum intensity was obtained at 613 nm. Under the optimum conditions, the enhanced fluorescence intensity was proportional to the concentration of levodopa over the range of 3×10^-9-2.5×10^-7 mol L^-1 with limit of detection (LOD) of 4.37×10^-10 mol L^-1. The method offers higher sensitivity and selectivity which could be effectively applied for the determination of levodopa in pharmaceutical and biological samples.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.51-58
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• 2023

In this study, anaerobic co-digestion was carried out using desulfurization sludge and sewage sludge (primary sludge) to evaluate the effects of sulfur compounds in anaerobic digestion. The experiment was carried out in the form of a batch test using 500 mL duran bottle, and the mixing ratio of the feedstock was selected based on the ratio of COD/SO₄. As a result of the experiment, it was confirmed that the amount of biogas generated and the yield decreased at the mixing ratio of COD/SO₄ 20 or less. In particular, below COD/SO₄ 10, it was lower than seed (283.5 mL) which was set without feedstock to correct biogas generated by itself from seed sludge. Methane yield tended to decrease from a ratio of COD/SO₄ 20 or less to 0.135 m³/kg VS compared to 0.396 m³/kg VS of COD/SO₄ 50. In addition, compared to 0.0097 m³/kg VS of hydrogen sulfide yield from COD/SO₄ 50, the ratio of COD/SO₄ 20 increased sharply to 0.0223 m³/kg VS, and in particular, the highest result was 0.0855 m³/kg VS in COD/SO₄ 10. Based on these results, it is judged that the effect of sulfide in anaerobic digestion can have an adverse effect if the COD/SO₄ ratio decreases to less than 20.

• Analytical Science and Technology
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• v.29 no.4
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• pp.162-169
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• 2016

The purpose of this study was to compare the relative bioavailability of synthetic Vitamin C and Nutra-C^® (calcium ascorbate) using a randomized parallel pharmacokinetics study design. Under fasting conditions, 20 healthy volunteers were randomly allocated to receive a single oral dose (500 mg of ascorbic acid) of either synthetic Vitamin C or Nutra-C^®. Fasting blood was collected pre-dose and 1, 2, 3, 4, 7 and 10 hr post-dose. The ascorbic acid content of human serum was determined using HPLC with ultraviolet detection. The fasting serum ascorbic acid concentrations of synthetic Vitamin C and Nutra-C^® were 6.734 ± 2.09 ng/mL (n = 10) and 7.542 ± 2.96 ng/mL (n = 10), respectively. The bioavailability of Nutra-C^® was significantly greater (128 %, p < 0.05) than that of the synthetic Vitamin C.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.54-60
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• 2024

This study investigated the effectiveness of using pathogens and aqueous acids to reduce the Aspergillus ochraceus and Rhodotorula mucilaginosa contamination in livestock production environments. For this study, 1 mL of each bacterial suspension (10⁷-10⁸ spores/mL) was inoculated on a knife surface, dried at 37℃, and used under each treatment condition. First, to investigate the effect of organic acids, acetic, lactic, and citric acids were used. Subsequently, to select the appropriate concentration, they were prepared at concentrations of 0.5, 1, 2, 3, 4, and 5%, respectively. Accordingly, to further maximize the effect of organic acid treatment, we combined the treatment with ultraviolet light. The two strains showed a significant difference (P<0.05) compared to the initial strain, with a greater than 90% decrease in the concentrations of all organic acids. Consequently, acetic and lactic acids decreased by approximately 5 and 2 log colony forming unit (CFU)/cm², respectively, when treated with ultraviolet light (360 mJ/cm²); however, citric acid decreased by less than 1 log CFU/cm². However, when manufactured with 4% acetic acid, a severe malodor was emitted, making it difficult for workers to use it in a production environment. Accordingly, the optimal treatment conditions for organic acid and ultraviolet light for application were selected as follows: immersion in a 4% lactic acid solution for 1 minute and then, sterilization with ultraviolet light at 360 mJ/cm². Finally, when a pork meat sample was cut with a knife that was finally washed with lactic acid and treated with ultraviolet light, the low level of inoculum transferred from the cleaned knife to the surface of the sample was not detected. In conclusion, using this established method can prevent cross-contamination of the surface of the meat during processing.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.2
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• pp.125-134
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• 2024

The present study was conducted to explore relationships between anemia and estimated glomerular filtration rate (eGFR) and urine microalbumin/creatinine ratio (uACR) in Korean adults with or without metabolic syndrome (MetS). The data of 4,943 adults aged ≥20 years who participated in KNHNES V-3 (2012) were analyzed. In the non-MetS group, the odds ratio (OR) for anemia of those with a decreased eGFR {eGFR<60 mL/min/1.73 m², 3.85 (95% confidence interval [CI], 2.03~7.30)} was significant as was the OR of those with decreased eGFR plus elevated uACR (eGFR<60 mL/min/1.73 m² and uACR≥30 mg/g, 5.81 [95% CI, 2.60~13.02]). In the MetS group, ORs for anemia for those with an elevated uACR (2.18 [95% CI, 1.11~4.27]), a decreased eGFR (3.74 [95% CI, 1.11~12.55]), or a decreased eGFR plus an elevated uACR (16.79 [95% CI, 5.93~47.57]) were significant. In conclusion, in non-MetS, anemia was associated with a low eGFR, whereas in MetS, anemia was associated with a low eGFR and an elevated uACR. In addition, the OR for anemia was greatly increased when eGFR was diminished and uACR was elevated regardless of MetS and MetS status.

• Journal of Electrochemical Science and Technology
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• v.13 no.4
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• pp.424-430
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• 2022

In the study, Ni²⁺ (nickel) removal from synthetically prepared wastewater by electrocoagulation method, which is one of the electrochemical treatment processes, was investigated and parameters such as current density, pH, mixing speed, initial Ni²⁺ concentration, supporting electrolyte type and concentration were determined to determine Ni²⁺ removal efficiencies effects were studied. Experiment conditions during 30 minutes of electrolysis; the current density was determined as 0.95 mA/cm², the initial pH of the wastewater was 6, the mixing speed was 150 rpm, and the initial nickel concentration was 250 mg/L. The Ni²⁺ removal efficiency was obtained as 75.99% under the determined experimental conditions, while the energy consumption was calculated as 3.15 kW-h/m³. In the experiments, it was observed that the type and concentration of the supporting electrolyte did not have a significant effect on the Ni²⁺ removal efficiency. In the trials where the effect of the support electrolyte concentration was examined, the Ni²⁺ removal efficiency was 75.99% in the wastewater environment without the supporting electrolyte, while the Ni²⁺ removal efficiency was 81.55% when 7.5 mmol/L NaCl was used after the 30-minute reaction, and the energy consumption was 2.15 kW-h/m³ obtained as. As a result of the studies, it was concluded that the electrocoagulation process can be applied in the treatment of wastewater containing Ni²⁺.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.261-271
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• 2024

Sulfur is one of the inorganic elements used by plants to develop and produce phytoalexin to resist certain diseases. This study reported a method for preparing a material for plant disease resistance. Sulfur nanoparticles (SNPs) stabilized in the chitosan-Cu²⁺ (CS-Cu²⁺) complex were synthesized by hydrolysis of Na₂S₂O₃ in an acidic medium. The obtained SNPs/CS-Cu²⁺ complex consisting of 0.32% S, 4% CS, and 0.7% Cu (w/v), contained SNPs with an average size of ~28 nm as measured by transmission electron microscopy images. The X-ray diffraction pattern of the SNPs/CS-Cu²⁺ complex showed that SNPs had orthorhombic crystal structures. Interaction between SNPs and the CS-Cu²⁺ complex was also investigated by ultraviolet-visible. Results in vitro nematicidal effect of materials against Meloidogyne incognita showed that SNPs/CS-Cu²⁺ complex was more effective in killing second-stage juveniles (J2) nematodes and inhibiting egg hatching than that of CS and CS-Cu²⁺ complex. The values of LC₅₀ in killing J2 nematodes and EC₅₀ in inhibiting egg hatching of SNPs/CS-Cu²⁺ complex were 75 and 51 mg/l, respectively. These values were lower than those of CS and the CS-Cu²⁺ complex. The test results on the nematicidal effect against M. incognita on coffee pots showed that the SNPs/CS-Cu²⁺ complex was 100% effective at a concentration of 150 mg/l. Therefore, the SNPs/CS-Cu²⁺ complex could be considered as a biochemical material with potential for agricultural applications to control root-knot nematodes.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.4
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• pp.377-383
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• 2021

Purpose: We investigated the association of effector memory (EM) CD8⁺ T cell and CD4⁺ T cell immunity with metabolic syndrome (MS). Methods: Surface and intracellular staining of peripheral blood mononuclear cells was performed. Anti-interleukin-7 receptor-alpha (IL-7Rα) and CX3CR1 antibodies were used to stain the subsets of EM CD8⁺ T cells, while anti-interferon-gamma (IFN-γ), interleukin-17 (IL-17), and forkhead box P3 (FOXP3) antibodies were used for CD4⁺ T cell subsets. Results: Of the 47 obese children, 11 were female. Children with MS had significantly higher levels of serum insulin (34.8±13.8 vs. 16.4±6.3 µU/mL, p<0.001) and homeostasis model assessment of insulin resistance (8.9±4.1 vs. 3.9±1.5, p<0.001) than children without MS. Children with MS revealed significantly higher frequencies of IL-7Rα^low CD8⁺ T cells (60.1±19.1% vs. 48.4±11.5%, p=0.047) and IL-7Rα^lowCX3CR1⁺ CD8⁺ T cells (53.8±20.1% vs. 41.5±11.9%, p=0.036) than children without MS. As the serum triglyceride levels increased, the frequency of IL-7Rα^lowCX3CR1⁺ and IL-7Rα^highCX3CR1^- CD8⁺ T cells increased and decreased, respectively (r=0.335, p=0.014 and r=-0.350, p=0.010, respectively), in 47 children. However, no CD4⁺ T cell subset parameters were significantly different between children with and without MS. Conclusion: In obese children with MS, the changes in immunity due to changes in EM CD8⁺ T cells might be related to the morbidity of obesity.

• Analytical Science and Technology
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• v.16 no.6
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• pp.443-449
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• 2003

Thermal neutron irradiation experiment of boric acid solution was carried out using HANARO in following three conditions: (A) $^{10}B$ concentration = $203.0{\mu}g/mL$, irradiation time = 1 hr; (B) $^{10}B$ concentration = $381.4{\mu}g/mL$, irradiation time = 1 hr; (C) $^{10}B$ concentration = $381.4{\mu}g/mL$, irradiation time = 0.5 hr. The amount of lithium produced from $^{10}B(n{\cdot}{\alpha})^7Li$ reaction which was generated on neutron irradiation, was measured by flameless atomic absorption spectroscopy. The concentration of $^7Li$ measured in the three experiments was $0.18{\mu}g/mL$ (78.3% of theoretical value, $0.23{\mu}g/mL$) in (A), $0.31{\mu}g/mL$ (70.5% of theoretical value, $0.44{\mu}g/mL$) in (B) and $0.16{\mu}g/mL$ (71.6% of theoretical value, $0.22{\mu}g/mL$) in (C). The pH value of irradiated boric acid was shifted to considerably low. It is estimated that boric acid would be transformed into the polyborate fonn, by radiolysis products of water, which has high dissociation constant.

• Natural Product Sciences
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• v.26 no.3
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• pp.207-213
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• 2020

Characterization and in vitro inhibition studies of protease inhibitor from the mushroom Pleurotus floridanus (PfTI) towards the pest Papilio demoleus is studied. The addition of 1 mM Mn²⁺, Na²⁺, Ba²⁺ and Ni ²⁺ enhanced the PfTI activity. The ICP-atomic emission spectrum showed the presence of Ca²⁺, Mg²⁺ and Zn²⁺ in the PfTI. Surfactants SDS and CTAB at a concentration of 1% reduced the PfTI activity whereas, the nonionic detergents Triton X and Tween 80 increased the activity. The inhibitory activity gradually decreased with increase in concentration of DMSO and H₂O₂. The activity was increased by dithiothreitol up to a concentration of 80 μM and inactivated at 140 μM. The activity of PMSF modified PfTI was drastically reduced to 0.234 U/mL at 4 mM concentration and similar results were obtained for modification of cysteine by N-Ethylmaleimide at slightly higher concentrations. The complex of trypsin and PfTI showed complete loss in fluorescence intensity at 343 nm compared with control. In vitro inhibition studies of PfTI with midgut proteases isolated from citrus pest P. demoleus with protease activity of 1.236 U was decreased to 0.613 U by 50 μL (0.1 mg/mL) of the inhibitor. Inhibitor was stable up to 0.04 M concentration of HCl.