• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.601-610
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• 1998

This study was carried out to investigate the possibility of supplemental UV-B application to the hardening phase of container-grown Betula platyphylla seedlings. The containerized seedlings were grown in a growth chamber for four months and then treated with UV-B(UV-$B_{BE}$ $3.2KJ\;m^{-2}\;day^{-1}$ and $5.2KJ\;m^{-2}\;day^{-1}$) radiation and water stress regime(irrigation in one week interval) for four weeks. The differences in growth and physiological responses of the seedlings before and after the treatments were analyzed. UV-B radiation and water stress reduced height growth and leaf dry mass accumulation of the seedlings. The root collar diameter growth was reduced by UV-B radiation but increased by water stress. The reduction in leaf dry weight by UV-B radiation and water stress reduced T/R ratio of the seedling. The reduction in T/R ratio was the most apparent by water stress. Chlorophyll index observed by a chlorophyll meter was the lowest in the $5.2KJ\;m^{-2}\;day^{-1}$ of UV-B radiation, and those in the $3.2KJ\;m^{-2}\;day^{-1}$ and water stress were similar. UV-B radiation and water stress reduced both water content in the seedlings and leaf water potential, and increased leaf osmatic pressure. The water content of leaves and shoots was reduced more rapidly by UV-B radiation than by water stress treatment. In conclusion, growth responses and physiological changes in water relation by supplemental UV-B radiation which was applied to the hardening phase of container-grown Betula platyphylla seedlings were similar results to the water stress treatment.

• Journal of Environmental Science International
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• v.6 no.4
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• pp.369-378
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• 1997

The effects of various intensity of W-B on barley seeding were investigated by PS I and II activities and chlorophyll fluorescence. The Inhibitory effect of UV-B radiation on electron transport activity was Increased as the intensity of UV-B Irradiation was increased. Especially, PS I is more sensitive to UV-B radiation than PS I is. By the addition of uncle electron donor, DPC, to the chloroplasts of the barley seedlings treated with UV-B, the photoreduction of DCPIP was recovered by only 1 IBI on electron transport activity. However, the activity of PS II was Inhibited by 45% by the treatment with UV-B, but recovered it only 11% by the addition of DPC. These suggest that other sites besides the oxidation site of PS II may be affected more by UV-B Irradiation. As the intensify of UV-B was Increased, Fo was Increased while Fv was decreased, and thus Fv/Fm was decreased. This means that photochemical efficiency was reduced. With this parameters, it might be that UV-B radiation affected adversely to around PS II.

• Journal of the Korean GEO-environmental Society
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• v.7 no.3
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• pp.21-29
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• 2006

The treatment performance of ozonation and three types of advanced oxidation processes (AOPs) such as $O_3/H_2O_2$, $O_3/UV$, $O_3/H_2O_2/UV$ was experimentally investigated for the treatment of refractory synthetic dye wastewater. The removal efficiency of $COD_{cr}$, color and biodegradability ($BOD_5/COD_{cr}$) were relatively evaluated in each treatment unit with simulated dye wastewater. Optimal operational conditions of pH, temperature, dosage and circulation flow rate were also investigated. All suggested processes revealed an effectiveness for the removal of color within a short operational time, moreover, $O_3/H_2O_2/UV$ process showed the highest $COD_{cr}$ removal and biodegradability enhancement among proposed oxidation process.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.677-688
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• 2006

Currently, the application of $TiO_2$ photocatalyst has been focused on purification and treatment of wastewater. However, the use of conventional $TiO_2$ slurry photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we studied that solar light/$TiO_2$ film system was designed and developed in order to examine disinfection characteristics of sewage wastewater treatment. The optimum conditions for disinfection such as solar light intensity, characteristic of sewage wastewater, amounts of $TiO_2$ and comparison of solar ligth/$TiO_2$ systems with UV light/$TiO_2$ system was examined. The results are as follows: (1) photocatalytic disinfection process with solar light in the presence of $TiO_2$ film more effectively killed total coliform (TC) than solar light or $TiO_2$ film absorption only. (2) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with remain resistant material. (3) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with the increase of amounts of $TiO_2$. (4) TC survival ratio decreased linearly with increasing UV light intensity. (5) The disinfection effect of solar light/$TiO_2$ slurry system decreased more than UV light/$TiO_2$ film systems. (6) The disinfection reaction followed first-order kinetics. We suggest that solar light instead of using artificial UV light was conducted to investigate the applicability of alternative energy source in the disinfection of TC and the degradation of organic material.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.645-654
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• 1994

Photocatalytic oxidation conditions of reactant recirculation flow rate 275 mL/min, aeration rate 2 LPM and $UV+TiO_2+H_2O_2$(500 mg/L) proved to be appropriate for water including organic materials treatment. With increasing turbidity and suspended solids concentration, at turbidity 10 NTU-suspended solids concentration 29 mg/L the phenol degradation efficiency increased, which in turn decreased at turbidity 50 NTU-suspended solids concentration 170 mg/L, however no significant differences were observed, demonstrating similar results with those obtained at zero turbidity and suspended solids concentration. The degradation efficiency of phenol decreased with increasing influent phenol concentrations. The $UV+TiO_2+H_2O_2$ photocatalytic advanced oxidation process conducted is considered to be possibly applied to the drinking water treatment, and the post-treatment process of biological wastewater treatment.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.239-245
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• 2007

The effect of ultraviolet-B (UV-B) radiation on photosynthesis was studied by the simultaneous measurements of $O_2$ evolution and chlorophyll (Chl) fluorescence in tobacco leaves. When the tobacco leaves were teated with UV-B (1 $W{\cdot}m^{-2}$), the maximal photosynthetic $O_2$, evolution (Pmax; 4.60 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) was decreased with increasing time of UV-B treatment showing 80% decline after 4 h treatment. Chl fluorescence parameters were also affected by ultraviolet-B. Fo was increased while both Fm and Fv were decreased, resulted in the decreased of photochemical efficiency of PSII (Fv/Fm). Non-radiative dissipation of absorbed light as heat as estimated as NPQ (Fm/Fm' - 1) was also decreased with increasing time of UV-B treatment while the extent of photochemical quenching (qP) was not changed. Thus, the ratio of (1-qP)/NPQ parameter was also increased with increasing time of UV-B treatment indicating PSII is under the threat of photoinhibition. The result indicate that UV-B primarily decreases the capacity to dissipate excitation energy by trans-thylakoid pH, which in turn inhibits PSII activity.

• Polymer(Korea)
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• v.38 no.3
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• pp.391-396
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• 2014

Polymer microneedles can be fabricated by a micromolding method, an easy and cost-effective method. However, it is not easy to achieve uniform coating with an aqueous coating solution due to hydrophobic surface of polymer microneedles. 3-Dimensional coating polymer microneedles could deliver more than twice as much dose as in-plane metal microneedles by increasing coating area and the number of microneedles per unit area. A uniform coating was not obtained by addition of coating additives in the coating solution. The satisfied coating was achieved by treatment of surface of polymer microneedle with metal deposition and UV/ozone, and UV/ozone treatment was an ultimate surface treatment method based on biological safety. Calcein coating polymer microneedles were prepared by using UV/ozone treatment and followed dip-coating, and they delivered calcein in porcine skin successfully after 15 min of insertion.

• Journal of Ginseng Research
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• v.45 no.3
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• pp.456-463
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• 2021

Background: Keratinocytes form a physical barrier and act as an innate immune cell in skin. Keratinocytes secrete pro-inflammatory cytokines, such as interleukin (IL)-1β, resulting from inflammasome activation when exposed to ultraviolet (UV) irradiation. Korean Red Ginseng extracts (RGE) have been well-studied as modulators of inflammasome activation in immune cells, such as macrophages. In the study, we elucidated the role of RGE on the UV-mediated inflammasome activation in keratinocytes compared with that in macrophages. Methods: Human skin keratinocyte cells (HaCaT), human epidermal keratinocytes (HEK), human monocyte-like cells (THP-1), and mouse macrophages were treated with RGE or a saponin fraction (SF) or non-saponin fraction (NS) of RGE before and after UV irradiation. The secretion levels of IL-1β, as an indicator of inflammasome activation, were analyzed. Results: The treatment of RGE or SF in macrophages after UV irradiation inhibited IL-1β secretion, but similar treatment in HaCaT cells did not. However, the treatment of RGE or SF in HaCaT cells in the presence of poly I:C, a toll-like receptor (TLR) 3 ligand, before UV exposure elicited the inhibition of the IL-1β secretion. The inhibition was caused by the disruption by RGE or SF of the TLR mediating up-regulation of the pro-IL-1β and NLRP3 genes during the priming step. Conclusion: RGE and its saponins inhibit IL-1β secretion in response to UV exposure in both keratinocytes and macrophages. In particular, RGE treatment interrupted only the priming step in keratinocytes, although it did attenuate both the priming and activation steps in macrophages.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.596-606
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• 2016

The growth and contents of anthocyanins and ascorbic acid in lettuce(Lactuca sativa L., 'Jeokchima') as affected by supplemental UV-A LED irradiation under different light quality and photoperiod conditions were analyzed in this study. Five light qualities, namely B (blue LED), R (red LED), BUV (blue LED+UV-A LED), RUV (red LED+UV-A LED) and Control (white fluorescent lamps) with photoperiods of 12/12 hours (day/night), 16/8 hours, or 20/4 hours were provided to investigate the effects of light quality and photoperiod on the growth and accumulation of anthocyanins and ascorbic acid in lettuce leaves. As measured 28 days after transplanting, the number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce were significantly affected by light quality and photoperiod. The number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce grown under R treatment increased with increasing light period. By contrast, leaf development was inhibited, but chlorophyll content increased, under B treatment. Supplemental UV-A irradiation significantly decreased leaf length, leaf width, leaf area and shoot fresh weight. Anthocyanins in lettuce increased significantly with decreasing dark period under B treatment. A synergistic effect of supplemental UV-A LED irradiation on anthocyanins accumulation was found for lettuce leaves grown under R treatment but not B treatment. Ascorbic acid in lettuce was greatly affected by photoperiod. Ascorbic acid content at BUV and RUV treatments increased by 20-30% compared to without UV-A LED irradiation. From these results, it was concluded that growth and contents of anthocyanins and ascorbic acid in lettuce are significantly affected by supplemental UV-A LED irradiation. The results obtained in this study will be informative for efforts to improve the nutritional value of leafy vegetables grown in plant factories.

• Food Science and Preservation
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• v.15 no.6
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• pp.922-926
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• 2008

The effect of UV-C irradiation on microbial growth and the quality of imported dried filefish and octopus during storage was examined. Samples of imported dried filefish and octopus were irradiated at 0, 5, 10 and $20\;kJ/m^2$ and stored for 3 months at $20^{\circ}C$ or for 6 days at $4^{\circ}C$. Exposure times of 5 min 33 sec, 11 min 6 sec, and 22 min 12 sec were used. UV-C treatment of the imported dried filefish and octopus decreased the populations of aerobic bacteria, yeasts and molds in proportion to radiation dose. Compared to the control, total aerobic bacteria, and yeast and mold populations were significantly lower (1-2 log CFU/g) with UV-C treatment of $20\;kJ/m^2$. UV-C irradiation caused negligible changes in the Hunter color L, a and b values. These results indicate that UV-C irradiation could be useful in inhibiting microbial growth on imported dried fish without impairing quality during storage.