• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.431-435
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• 2009

This study was conducted to compare the effect of various LED and UVa light to enhanced coloration of paprika fruits cultivars; 'Special', 'Helsinki'. Immatured paprika fruits were irradiated with red LED, blue LED and UVa lights which were high intensity (red: $50{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, blue: $70{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, UVa: $3{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and low intensity (red: $20{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, blue: $40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, UVa: $0.25{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). The coloration of 'Special' cultivar was increased the fastest in high intensity UVa light for 2 days after treatment. There were no significantly difference among treatments except the low intensity UVa light. The coloration of 'Helsinki' was increased the fastest in blue LED light, and followed by red LED light and UVa light for 2 days after treatment. The $a^*/b^*$ value of 'Special' and $b^*$ value of 'Helsinki' that indicated the paprika fruit coloration were generally higher high intensity LED and UVa lights than low intensity LED and UVa lights. We couldn't find out any significantly different coloration effect among all treatments in final days of coloration. and rather than UVa treatment fruit shrunk the surface of paprika fruits.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.99-105
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• 2012

Purpose: The purpose of this study is to demonstrate inactivation effect of UVA-LED ultraviolet radiation upon Pseudomonas aeruginosa and Staphylococcus aureus which are the major bacteria causing eye diseases. Methods: The small sterilization device was made using UVA-LED of 400 nm. After Pseudomonas aeruginosa was diluted to $10^{-7}$ and Staphylococcus aureus to $10^{-5}$ and diluted solutions were put onto each liquid medium. They were irradiated by 400 nm of UVA for different amount of time; 15 min, 30 min, 60 min, 120 min, 240 min, 360 min and 480 min each. Results: The data from sterilization test was solved to regression line equation and the target log inactivation was obtained. The 3 log inactivation UV irradiation value of Pseudomonas aeruginosa was 54,847 UV dose ($mJ/cm^2$) and irradiation time was 135.42 min while the 3 log inactivation of Staphylococcus aureus was 39,066 UV dose ($mJ/cm^2$) and irradiation time was 98.72 min. Conclusions: The inactivation effect of sterilization method using 400 nm of UVA-LED upon Pseudomonas aeruginosa and Staphylococcus aureus has been verified and it is considered as a useful method in inactivating the contact lenses.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1219-1226
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• 2017

In this paper, it is performed the optimal design of the UV LED bar which can be used variously. The UV LED Bar emits ultraviolet rays, so it is important to emit ultraviolet rays constantly for the purpose of use. In order to emit a certain amount of ultraviolet rays as ever, the ultraviolet ray emission should be driven by a constant current source within the operable input voltage range. And also the heat dissipation is particularly important because of the long ultraviolet emission retention time due to the UV utilization characteristics. In addition, since human body protection is essential, the algorithm is configured to operate according to human body detection using distance sensor and Bluetooth. Three 365nm UV LEDs were used in series to emit ultraviolet UVA, operating at the constant current of 500mA with an efficiency of 87.5% and a power consumption of 6.006W. The ultraviolet radiation dose was measured at $5.35mW/cm^2$ at the distance of 10 cm when measured by the Lutron ultraviolet measuring instruments.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.237-244
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• 2005

Sunscreens have been in use for about 70years and 'tanning without burning' was propagated as their major advantage. The objective changed from 'getting a tanned skin' to 'getting skin protection' since UV have been proposed to a major risk of skin cancer and the risk of developing skin cancer related also to non-burning UVA. The new expectation from consumers has triggered the development of new UV absorbers and led to the approval of 7 new, organic UV absorbers in Europe over the last few years. The significant progress due to these new UV absorbers will be discussed in this report. These UV absorbers provide an efficient absorption of UV radiation (UVB and/or UVA) and easily incorporate in any kind of formulation. These are also safe, i.e. devoid of adverse effects. These new filters give the formulators new possibilities to cover the whole UV range iron 290 to 400 nm, and also to use less filter due to the boosting effect of the new UVA and broadband fitters.

• Journal of Bio-Environment Control
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• v.28 no.1
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• pp.1-8
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• 2019

The study aimed to determine effects of light emitting diode (LED) and the ultraviolet radiation (UVA) light of plant factory on plant growth and ascorbic acid content of spinach (Spinacia oleracea cv. Shusiro). Plants were grown in a NFT (Nutrient Film Technique) system for 28 days after transplanting with fluorescent light (FL, control), LEDs and UVA (Blue+UVA (BUV), Red and Blue (R:B(2:1)) + UVA (RBUV), Red+UVA (RUV), White LED (W), Red and Blue (R:B(2:1)), Blue (B), Red (R)) under the same light intensity ($130{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and photoperiod (16/8h = day/night). All the light sources containing the R (R, RB, RUV, and RBUV) showed leaf epinasty symptom at 21 days after transplanting (DAT). Under the RUV treatment, the lengths of leaf and leaf petiole were significantly reduced and the leaf width was increased, lowering the leaf shape index, compared to the R treatment. Under the BUV, however, the lengths of leaf and leaf petiole were increased significantly, and the leaf number was increased compared to B. Under the RBUV treatment, the leaf length was significantly shorter than other treatments, while no significant difference between the RBUV and RB for the fresh and dry weights and leaf area. Dry weights at 28 days after transplanting were significantly higher in the R, RUV and BUV treatments than those in the W and FL. The leaf area was significantly higher under the BUV treatment. The ascorbic acid content of the 28 day-old spinach under the B was significantly higher, followed by the BUV, and significantly lower in FL and R. All the integrated data suggest that the BUV light seems to be the most suitable for growth and quality of hydroponically grown spinach in a plant factory.

• Korean Journal of Optics and Photonics
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• v.30 no.4
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• pp.146-153
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• 2019

The exposure system is a device that transfers a circuit pattern to a desired location. To display patterns on a substrate without deforming the optical characteristics, the characteristics of the optical exposure system are very important. Therefore, to form a microcircuit pattern, a small divergence angle should impinge on the irradiation area. Also, since the light from the source must react uniformly with the photosensitizer, it must have high luminance efficiency and uniformity of illumination. In this paper a parabolic reflector and an aspherical lens were designed to solve the problem of narrow-angle implementation, and it was confirmed by simulation analysis after their arrangement that the beam angle, uniformity, and maximum illuminance satisfied the target performance.

• Food Science of Animal Resources
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• v.43 no.6
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• pp.1087-1110
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• 2023

The growing demand for sustainable food production and the rising consumer preference for fresh, healthy, and safe food products have been driving the need for innovative methods for processing and preserving food. In the meat industry, this demand has led to the development of new interventions aimed at extending the shelf life of meats and its products while maintaining their quality and nutritional value. Cold plasma has recently emerged as a subject of great interest in the meat industry due to its potential to enhance the microbiological safety of meat and its products. This review discusses the latest research on the possible application of cold plasma in the meat processing industry, considering its effects on various quality attributes and its potential for meat preservation and enhancement. In this regard, many studies have reported substantial antimicrobial efficacy of cold plasma technology in beef, pork, lamb and chicken, and their products with negligible changes in their physicochemical attributes. Further, the application of cold plasma in meat processing has shown promising results as a potential novel curing agent for cured meat products. Understanding the mechanisms of action and the interactions between cold plasma and food ingredients is crucial for further exploring the potential of this technology in the meat industry, ultimately leading to the development of safe and high-quality meat products using cold plasma technology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.4
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• pp.237-240
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• 2016

The improvement of irradiation intensity and irradiation uniformity is essential for large area and high power UVA light source application. In this study, large number of chips bonded by micro soldering technique were driven by low current, and current limiting diodes were configured to supply constant current to parallel circuits consisting of large number of series strings. The dimension of light source module circuit board was $350{\times}90mm^2$ and 16,650 numbers of 385 nm flip chip LEDs were used with a configuration of 90 parallel and 185 series strings. The space between LEDs in parallel and series strings were maintained at 1.9 mm and 1.0 mm distance, respectively. The size of the flip chip was $750{\times}750{\mu}m^2$ were used with contact pads of $260{\times}669{\mu}m^2$ size, and SAC (96.5 Sn/3.0 Ag/0.5 Cu) solder was used for flip chip bonding. The fabricated light source module with 7.5 m A supply current showed temperature rise of $66^{\circ}C$, whereas irradiation was measured to be $300mW/cm^2$. Inaddition, 0.23% variation of the constant current in each series string was demonstrated.

• Biomedical Science Letters
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• v.26 no.4
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• pp.288-295
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• 2020

Infection of Helicobacter pylori on gastric mucosa is associated with various gastric diseases. According to the WHO, H. pylori causes gastric cancer and has been classified as a class I carcinogen. Riboflavin is an essential vitamin which presents in a wide variety of foods. Previous studies have shown that riboflavin/UVA was effective against the growth inhibition of Staphylococcus aureus, S. epidermidis and multidrug-resistant Pseudomonas aeruginosa and had the potential for antimicrobial properties. Thus, we hypothesized that riboflavin has a potential role in the growth inhibition of H. pylori. To demonstrate inhibitory concentration of riboflavin against H. pylori, we performed agar and broth dilution methods. As a result, we found that riboflavin inhibited the growth of H. pylori. The MIC was 1 mM in agar and broth dilution test. Furthermore, to explain the inhibitory mechanism, we investigated whether riboflavin has an influence on the replication-associated molecules of the bacteria using RT-PCR to detect mRNA expression level in H. pylori. Riboflavin treatment of H. pylori led to down-regulation of polA and dnaB mRNA expression levels in a dose dependent manner. After then, we also confirmed whether riboflavin has cytotoxicity to human cells. We used AGS, a gastric cancer cell line, and treated with riboflavin did not show statistically significant decrease of cell viability. Thus, these results indicate that riboflavin can suppress the replication machinery of H. pylori. Taken together, these findings demonstrate that riboflavin inhibits growth of H. pylori by inhibiting replication of the bacteria.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1382-1389
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• 2022

Asterias pectinifera, a species of starfish and cause of concern in the aquaculture industry, was recently identified as a source of non-toxic and highly water-soluble collagen peptides. In this study, we investigated the antioxidant and anti-photoaging functions of compounds formulated using collagen peptides from extracts of Asterias pectinifera and Halocynthia roretzi (AH). Our results showed that AH compounds have various skin protective functions, including antioxidant effects, determined by measuring the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl radicals, as well as anti-melanogenic effects, determined by measuring tyrosinase inhibition activity. To determine whether ethosome-encapsulated AH compounds (E(AH)) exert ultraviolet (UV)-protective effects, human dermal fibroblasts or keratinocytes were incubated with E(AH) before and after exposure to UVA or UVB. E(AH) treatment led to inhibition of photoaging-induced secretion of matrix metalloproteinase-1 and interleukin-6 and -8, which are associated with inflammatory responses during UV irradiation. Finally, the antibacterial effects of AH and E(AH) were confirmed against both gram-negative and gram-positive bacteria. Our results indicate that E(AH) has the potential for use in the development of cosmetics with a range of skin protective functions.