• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.226-232
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• 2009

The effects of UV-C irradiation on the quality characteristics of powdered foods, sunsik and misutkaru, were examined during storage, where samples were irradiated at doses of 27, 54, and 108 kJ/$m^2$, respectively. In addition, sunsik and misutkaru samples were inoculated with Enterobacter sakazakii as a pathogen and then irradiated at doses of 0.5, 1, and 5 kJ/$m^2$, respectively. After treatment, the sunsik and misutkaru samples were stored at $20^{\circ}C$. The microbiological data represented that populations of total aerobic bacteria, Bacillus cereus, and E. sakazakii were significantly (p<0.05) reduced with increasing UV-C doses. In addition, UV-C irradiation did not cause inferiority in the color quality of the samples during storage. Sensory evaluation results also indicated that there were no significant differences (p<0.05) among the irradiated samples. These results suggest that UV-C irradiation may be useful in maintaining the quality of sunsik and misutkaru during storage.

• Journal of Technologic Dentistry
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• v.43 no.3
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• pp.84-92
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• 2021

Purpose: The purpose of this study was to compare the dimension safety evaluation between a general ultrasonic cleaner and an ultrasonic cleaner equipped with UV-C (ultraviolet-C). Methods: An edentulous model was prepared. A denture base and an occlusal rim were fabricated, and scanning was performed. After scanning, a denture base and full arch artificial teeth were designed. The full arch artificial teeth were printed using a three-dimensional printer (n=10). The residual resin was washed with alcohol and then scanned (reference data). The printed specimens were classified and cleaned using a general ultrasonic cleaner (GU group) and an ultrasonic cleaner equipped with UV-C (UC group). After each washing, a rescan was performed (scan data). Reference data and scan data were superimposed using overlapping software. Data were statistically analyzed using the Mann-Whitney test (α=0.05). Results: In the deviation values of full arch artificial teeth, the GU group showed a high deviation of 18.02 ㎛ and the UC group showed a low deviation of 15.02 ㎛. The two groups demonstrated a statistically significant difference (p<0.05). Conclusion: Full arch artificial teeth prepared using photopolymerized resin were deformed according to the temperature of water generated in the ultrasonic cleaner. It is judged that there is no deformation according to the UV-C ultrasonic cleaner.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.99-105
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• 2007

Nonylphenol polyetoxylates (NPnEOs) metabolites; nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), nonylphenoxyacetic acid (NPEC) (collectively referred to "NPE-c") were examined for their degradations by using of lab-scale UV/photocatalytic silicagel (ultraviolet photocatalytic degradation in the presence of silicagel coated with titanium dioxide as a catalyst) reactor. NPE-c degradations by UV/photocatalytic silicagel treatment reached approximately 85-93 % after 40 min irradiation independently of its initial concentration (between ca. 0.5 and 2.0mg/l). Any intermediates under the NPE-c degradation were not identified by GC/MS sample analysis. Degradations of NPE-c were followed pseudo first-order kinetics. Then, the effectiveness of UV/photocatalytic silicagel treatment for degradation of NPE-c was in the order of NPEC > NP > NP1EO.

• Food Science of Animal Resources
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• v.44 no.2
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• pp.372-389
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• 2024

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.402-407
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• 2012

The effects of a combined treatment of aqueous chlorine dioxide ($ClO_2$) and ultraviolet-C (UV-C) irradiation on microbial growth in celery and cherries were investigated. Celery and cherry samples were treated with 50 ppm $ClO_2$, UV-C at dose of 10 kJ/$m^2$, and a combination of $ClO_2$ and UV-C. The changes in the counts of Escherichia coli O157:H7 inoculated in the celery and cherries as well as those of total aerobic bacteria, yeast and molds in the celery and cherries were investigated after each treatment. After the combined treatment of aqueous $ClO_2$ and UV-C irradiation, the populations of E. coli O157:H7 in the inoculated celery and cherries were reduced by 2.8 and 3.0 log CFU/g, respectively, compared to those of the control. For the un-inoculated celery and cherries, the populations of total aerobic bacteria were reduced by 2.9 and 1.8 log CFU/g, respectively, compared to the control. In addition, the populations of yeast and molds were decreased by 1.8 and 1.2 log CFU/g, respectively. These results suggest that the combined treatment of 50 ppm $ClO_2$ and UV-C at a dose of 10 kJ/$m^2$ would be an effective technology for decontamination and improving the microbiological safety in celery and cherries during chilled storage.

• Food Science and Preservation
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• v.21 no.4
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• pp.581-586
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• 2014

With the current consumer trend toward health and wellbeing, the demand for consumption of fresh cut vegetables has been increasing. As a popular vegetable with functional components, sedum (Sedum sarmentosum) is widely used in Korea as a side dish that needs no cooking. In this study, to provide a hurdle technology for postharvest sedum, the effects of combined treatment of 1% acetic acid for washing and $10kJ/m^2$ UV-C irradiation on the microbial growth and quality of sedum were examined. After the treatment, the sedum samples were stored at $10^{\circ}C$ for six days, and the results of their microbial analysis as well as their color, vitamin C content, and antioxidant activity were analyzed. The combined treatment with acetic acid and UV-C irradiation reduced the initial populations of the total aerobic bacteria and the yeast and molds in the sedum by 3.28 and 4.22 log CFU/g, respectively, compared to those in the control. The Hunter L, a, and b values of the sedum did not significantly differ across the treatments. In addition, the vitamin C content and the antioxidant activity decreased significantly during the storage, regardless of the treatment. These results suggest that the combined treatment with 1% acetic acid and $10kJ/m^2$ UV-C irradiation can be useful as a hurdle technology for retaining the microbiological safety and quality of sedum during its storage.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.28-32
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• 1998

Two organophosphorous insecticides, Dichlorovos and Chloropyrifos were degraded in the presence of UV irradiation, UV irradiation with $TiO_2$ powder and UV irradiation with sea sand using low pressure mercury lamp. The identification of these compounds was carried out by gas chromatograph with a nitrogen-phosphorous detector, Total Organic Carbon and Ion Chromatograph, respectively. Both dichlorvos and chloropyrifos, UV irradiation with sea sand were more degradable than UV irradiation and UV irradiation with $TiO_2$ powder. The final products were $Cl^-$ in Dichlorvos, $Cl^-$ $SO_4{^{2-}}$ in Chloropyrifos, respectively.

• Textile Coloration and Finishing
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• v.26 no.3
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• pp.159-164
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• 2014

Biodegradable Poly(butylene succinate), PBS, was photooxidized by UV/ozone irradiation and the effect of UV energy on the surface properties of the UV-irradiated PBS film were investigated by the measurement of reflectance, surface roughness, contact angles, chemical composition, and zeta potential. With increasing UV energy, reflectance decreased in the visible and ultraviolet regions particularly at the wavelength of 380nm. The irradiation produced nano-scale surface roughness including the maximum peak-to-valley roughness increased from 106nm for the unirradiated sample to 221nm at the UV energy of $10.6J/cm^2$. The improved hydrophilicity was due to the higher $O_{1s}/C_{1s}$ resulting from the introduction of polar groups such as C-O and C=O bonds. The surface energy of the PBS increased from $42.1mJ/m^2$ for the unirradiated PBS to $56.8mJ/m^2$ at the irradiation of $21.2J/cm^2$. The zeta potentials of the UV-irradiated PBS also decreased proportionally with increasing UV energy. The cationic dyeability of the PBS increased accordingly resulting from the improved affinity of the irradiated PBS surfaces containing photochemically introduced anionic and dipolar dyeing sites.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.649-655
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• 2010

This study investigated the degradation of phenol using sonication and/or UV-C. The effects of frequency, temperature, pH in solution, argon purging, with UV intensity were estimated in sonication-only, UV-only, and the combined reaction of sonication with UV. The optimum condition for degrading phenol in the sonication-only reaction was 35 kHz, $5^{\circ}C$, and pH 4. As this condition approximately 30% degradation of phenol was achieved within 360 min. However, phenol in the UV-only at $19.3\;mw/cm^2$ under the same condition was completely degraded within 60 min. In the combined system of sonication with UV, the degradation of phenol was well fitted to first-order rate model, and phenol was completely degraded within 360 min and 45 min at UV intensity of $7.6\;mW/cm^2$($17.3{\times}10^{-3}\;min^{-1}$) and $19.3\;mW/cm^2$($138.1{\times}10^{-3}\;min^{-1}$), respectively. Adding methanol, as a radical scavenger, in the phenol degradation in the sonication reaction indicates that OH radical is a major factor in the degradation of phenol. The order of degradation efficiencies of phenol was in the order of as follows; combined reaction of sonication with UV > UV-only > sonication-only.

• Journal of Life Science
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• v.12 no.3
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• pp.274-280
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• 2002

The metabolites related to phenylpropanoid pathway play an important role in the self-defense of plants and induced by environmental stress like wounding, pathogen attack, UV-irradiation and so on. The mRNA level of rite phenylalanine ammonia lyase (PAL) was increased at 12 h to 48 h, however it was gradually decreased 48 h to 60 h after UV irradiation. The PAL enzyme activities in rice were peaked at the time of 24 h after UV irradiation, on the other hand, it was not affected by wounding. The PAL enzyme activities in pepper were raised high at 24 h and 10 h by UV irradiation and wounding respectively. The cinnamic acid 4-hydroxylase (C4H) activities were increased by wounding treatment and were detected from 12 h to end time point of experiment, while UV-irradiation didn't affect the C4H activity in rice and pepper. These results were assumed that the action of isoflavonid has an alternative effect on the defenses which include wounding and UV irradiation and on the diverse roles in rice and hot pepper.