• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.432-441
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• 2016

Machaerium cuspidatum, a canopy liana, is a species of genus legume in the Fabaceae family and contributes to the total species richness in the tropical rain forests. In the present study, we investigated the antioxidative and anti-cancer effects of M. cuspidatum and its mode of action. The methanol extract of M. cuspidatum (MEMC) exhibited anti-oxidative activity with an $IC_{50}$ value of $1.66{\mu}g/ml$, and this was attributable to its 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity. MEMC also exhibited a cytotoxic effect and induced morphological changes in a dose-dependent manner in several cancer cell lines including human lung adenocarcinoma A549 cells, human hepatocellular carcinoma HepG2 cells, and human colon carcinoma HT29 cells. Moreover, MEMC treatment induced the accumulation of subG1 population, which is indicative of apoptosis in A549 and HepG2 cells. MEMC-induced apoptosis was confirmed by the increase in Annexin V-positive apoptotic cells and apoptotic bodies using Annexin-V staining and DAPI staining, respectively. Further investigation showed that MEMC-induced apoptosis was associated with the increase in p53 and Bax expression, and the decrease in Bcl-2 expression. In addition, MEMC treatment led to proteolytic activation of caspase-3, 8, and 9 and degradation of poly-ADP ribose polymerase (PARP). Taken together, these results suggest that MEMC may exert a beneficial anti-cancer effect by inducing apoptosis via both the extrinsic and intrinsic pathways in A549 and HepG2 cells.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.400-407
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• 2013

This study was performed to analyze the effect of light quality of discharge lamp on growth and phytochemicals contents of lettuce (Lactuca sativa L. cv. Jeokchima) grown under metal halide (MH) lamp, high-pressure sodium (HPS) lamp, and xenon (XE) lamp in a plant factory. Cool-white fluorescent (FL) lamp was used as the control. Photoperiod, air temperature, relative humidity, $CO_2$ concentration, and photosynthetic photon flux (PPF) in a plant factory were 16/8 h (day/night), $22/18^{\circ}C$, 70%, 400 ${\mu}mol{\cdot}mol^{-1}$, and 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. MH lamp had the greatest fraction of blue light (400-500 nm) of 23.0%. However, HPS lamp had the lowest fraction of 4.7% for blue light and the greatest fraction of 38.0% for red light (600-700 nm). At 11 and 21 days after transplanting, leaf length, leaf width, leaf area, shoot fresh weight, and shoot dry weight of lettuce as affected by the light quality of the discharge lamp were significantly different. The leaf area of lettuce grown under HPS, MH, and XE lamp increased by 45.7%, 16.3%, and 9.5%, respectively, as compared to the control. These results were similar for shoot fresh weight. Growth characteristics of lettuce grown under HPS lamp increased since HPS lamp had more fraction of red light. However, growth of lettuce grown under MH and XE lamp decreased since they had more fraction of blue light. As compared to the control, the ascorbic acid in lettuce leaves grown under discharge lamp decreased. The greatest anthocyanins accumulation of 0.70 mg/100 g was found at MH treatment. Anthocyanins content in lettuce leaves grown under XL and HPS lamp were 79.3% and 8.6%, respectively, compared with the control. Growth and phytochemicals contents of lettuce were highly affected by the different spectral distribution of the discharge lamp. These results indicate that the combination of discharge lamp or LED lamp for enhancing the light quality of discharge lamps is required to increase the growth and phytochemicals accumulation of lettuce in controlled environment such as plant factory.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.171-180
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• 2020

The effect of three different light qualities on growth, photosynthesis, quality and safe parameters of hydroponic cultivated spinach (Spinacia oleracea L.) were investigated indoor. Three different light qualities were created of red (660 nm), blue (450 nm) and green (550 nm) LEDs corresponding at ratio R660/B450 = 4/1 (RBL); R660/B450/G550= 5/2/3 (WWL); R660/B450/G550 = 1/1/1 (WL), which were tested at the same intensity (PPFD =190 μmol m^-2 s^-1). The results showed that the plant height and leaf number were the lowest in WL treatment. The SPAD, Net photosynthesis rate Pn, Fv/Fm, Leaf area index LAI values and all parameters of root characteristics were the highest in RBL treatment and were significantly different from two others. Fresh weight of stem, leaf and root, dry weight of root in the three light qualities were significantly different. In contrast, the highest K⁺ content in WL was different from WWL and RBL treatments, while Ca²⁺ and Fe²⁺ content were the highest in the RBL treatment. Vitamin C content was significantly different between the three treatments. nitrate and oxalic acid contents were the highest in WL treatment, whereas soluble-solids contents and vitamin C contents were the highest in RBL treatment. Oxalic acid, nitrate contents were observed tending reduced under WWL although oxalic acid content in RBL treatment was not different from WL and WWL treatments. In all three different light treatments were not detected Salmonella, E.coli. Our results suggest that RBL may be appropriate light for growth of spinach, but supplementary green light to a combination of red and blue LEDs at the reasonable rate can change the quality of spinach in a positive direction. Hydroponic cultivated spinach was safe for users.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.392-399
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• 2013

This study aimed to investigate responses of photosynthesis, plant growth, and phytochemical contents to different artificial light sources for 'Seneca RZ' and 'Gaugin RZ' two butterhead lettuce (Lactuca sativa L.). In this study, fluorescent lamps (FL), three colors LEDs (red, blue and white, 5 : 4 : 1; RBW) and metalhalide lamps (MH) were used as artificial lighting sources. Photoperiod, air temperature, relative humidity, EC, and pH in a cultivation system were maintained at 16/8 h, $25/15^{\circ}C$, 60~70%, $1.4{\pm}0.2dS{\cdot}m^{-1}$, and $6.0{\pm}0.5$, respectively. The photosynthetic rate of both two butterhead lettuce were the highest under RBW in middle growth stage. However, in late growth stage, the photosynthetic rate of both two butterhead lettuce were higher under RBW and MH than FL. The light sources showed significant results for plant growth but those effects were different to variety. Fresh and dry weight of 'Gaugin RZ' butterhead lettuce under MH were heavier than other lights in all growth stages. Growth of 'Seneca RZ' butterhead lettuce was maximized highest under MH in middle growth stage and FL in late growth stage. In the leaf tissue of 'Seneca RZ' butterhead lettuce, tipburn symptom occurred under all light sources and in the leaf tissue of 'Gaugin RZ' butterhead lettuce, it occurred under two light sources except for fluorescent lamps in late growth stage. kinds of lamp affect plant growth more than plant quality. Relative growth rate of both two butterhead lettuce was faster in middle growth stage than late stage. Growth of 'Gaugin RZ' was shown by kinds of lamp in middle growth stage and but it was not significantly affected by light sources and variety in late stage. Most of the phytochemical contents of two butterhead lettuce were significantly affected by different light sources. Contents of all vitamins showed higher than other light sources on RBW for both two lettuce, especially ${\beta}$-Carotene content of 'Gaugin RZ' was the highest. Plant growth, photosynthesis, and phytochemical contents were observed significant effects by different light sources for two butterhead lettuce but those effects were highly different between variety and kinds of phytochemicals. Therefore, the selection of optimum light source should be considered by variety and kinds of phytochemicals in the plant factory.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.225-236
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• 2019

BACKGROUND: Hydroponics is one of the methods for evaluating plant production using the inorganic nutrient solutions, which is applied under the artificial light conditions of plant factory system. However, the application of the conventional inorganic nutrients for hydroponics caused several environmental problems: waste from culture mediums and high nitrate concentration in plants. Organic nutrients are generally irrigated as a supplementary fertilizer for plant growth promotion under field or greenhouse conditions. Hydroponic culture using organic nutrients derived from the agricultural by-products such as dumped stems, leaves or immature fruits is rarely considered in plant factory system. Effect of organic or conventional inorganic nutrient solutions on the growth and nutrient absorption pattern of green and red leaf lettuces was investigated in this experiment under fluorescent lamps (FL) and mixture Light-Emitting Diodes (LEDs). METHODS AND RESULTS: Single solution of tomatoes (TJ) and kales (K) deriving from agricultural by-products including leaves or stems and its mixed solution (mixture ration 1:1) with conventional inorganic Yamazaki (Y) were supplied for hydroponics under the plant factory system. The Yamazaki solution was considered as a control. 'Jeockchima' and 'Cheongchima' lettuce seedlings (Lactuca sativa L.) were used as plant materials. The seedlings which developed 2~3 true leaves were grown under the light qualities of FL and mixed LED lights of blue plus red plus white of 1:2:1 mixture in energy ratio for 35 days. Light intensity of the light sources was controlled at 180 μmol/㎡/s on the culture bed. The single and mixture nutrient solutions of organic and/or inorganic components which controlled at 1.5 dS/m EC and 5.8 pH were regularly irrigated by the deep flow technique (DFT) system on the culture gutters. Number of unfolded leaves of the seedlings grown under the single or mixed nutrient solutions were significantly increased compared to the conventional Y treatment. Leaf extension of 'Jeockchima' under the mixture LED radiation condition was not affected by Y and YK or YTJ mixture treatments. SPAD value in 'Jeockchima' leaves exposed by FL under the YK mixture medium was approximately 45 % higher than under conventional Y treatment. Otherwise, the maximum SPAD value in the leaves of 'Cheongchima' seedlings was shown in YK treatment under the mixture LED lights. NO₃-N contents in Y treatment treated with inorganic nutrient at the end of the experiment were up to 75% declined rather than increased over 60 % in the K and TJ organic treatment. CONCLUSION: Growth of the seedlings was affected by the mixture treatments of the organic and inorganic solutions, although similar or lower dry weight was recorded than in the inorganic treatment Y under the plant factory system. Treatment Y containing the highest NO₃-N content among the considered nutrients influenced growth increment of the seedlings comparing to the other nutrients. However effect of the higher NO₃-N content in the seedling growth was different according to the light qualities considered in the experiment as shown in leaf expansion, pigmentation or dry weight promotion under the single or mixed nutrients.

• Korean Journal of Optics and Photonics
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• v.23 no.2
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• pp.64-70
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• 2012

We analyzed the changes in electrical and optical characteristics of 1 $mm^2$ multiple-quantum-well (MQW) blue LEDs grown on a c-plane sapphire substrate after a stress test. Experiments were performed by injecting 50 mA current for 200 hours to TO-CAN packaged sample chips. We selected the value of injection current for stress through the junction-temperature measurement by using the forward-voltage characteristics of a diode to maintain a sufficiently low junction temperature during the test. The junction temperature at the selected injection current of 50 mA was 308 K. Experiments were performed under the assumption that the average junction temperature of 308 K did not affect the characteristics of the ohmic contact and the GaN-based materials. Before and after the stress test, we measured and analyzed current-voltage, light-current, light distribution on the LED surface, wavelength spectrum and relative external quantum efficiency (EQE). After the stress test, it was observed experimentally that the optical power and the relative EQE decreased. We theoretically investigated and experimentally proved that these phenomena are due to the increased nonradiative recombination rate caused by the increased defect density.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.499-506
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• 2011

The purpose of this study was to search available resources for new natural colorants. The extraction efficiency of colorants from black cowpea seed coats and their storage stability were examined according to the various extraction and storage conditions in this study. The results obtained were as follows: the optical density (O.D.) values of the extracted colorants increased with increasing extract time and temperature. Extraction at pH 4 was seen to be the most efficient among the various pH conditions. The color of the extract solutions were seen to change with variation in pH, for example, anthocyanins display color changes from orange-red, to orange, to blue, to greenish-blue at pH 3.0, 4.0-6.0, 7.0 and 9.0-11.0, respectively. The color changes of the extract solutions over various storage periods were determined using UV/Vis spectra these color changes indicate characteristic absorption patterns and a discoloration index which indicates the rate of absorbance (532 nm/454 nm). Methionine addition influenced the storage stability of the colorant solutions and this addition led to better storage stability than non-addition. In paper chromatography of juice extracted colorant, a long stripe was seen on development. Among three colorants obtained via paper chromatography according to development rate, at least two different colorants were mixed indicated by the appearance, or not, of a shoulder at 552 nm depending on the extent of development.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.77-83
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• 2007

It is essential that second order nonlinear optical materials have low optical propagation losses in the wavelengths of second harmonic generation for practical applications in waveguides. Three dipolar chromophores substituted with nitro, cyano, and alkyl sulfone as an electron withdrawing group were prepared. The UV-Vis absorption spectra of the cyano and alkylsulfone chromophores showed a blue-shift compared to the nitro chromophore. The introduction of oxadiazole segment in the chromophore structure led to similar spectral shift. The blue-shift can produce low optical loses at second harmonics. The chromophores were successfully attached to a polyimide, yielding side chain polymers. The nonlinear optical property of the prepared optical polymers was determined by measuring electro-optic coefficient at 1.55 mm. The polymers exhibited high glass transition temperature of over $185^{\circ}C$ and thermal stability to $300^{\circ}C$ through differential scanning calorimeter analysis and thermal gravimetric analysis.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.478-483
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• 1995

To investigate the constituents of antimutagenic factor from brown rice, methanol extracts were fractionated into ether, ethylacetate, buthanol and aqueous fractions. The ether fractions showed distinct antimutagenic effect and active spot were selected by silica gel chromatography. The specific activity of active spot decreased with isolation of the active components from the methanol extract. Qualitative analyses of the active spot by using various spraying reagents revealed that ninhydrin and orcinol did not develop colored reactions. But, ferric chloride, 2,7-dichlorofluorescein, antimony pentachloride, phosphomolybdic acid, bromothymol blue and rhodamine 6G led to colored reactions. These results suggested that the consitituents of active material were neither polar nor nitrogen-containing compounds and that they may contain phenolic compounds and fatty acid derivatives. Main compounds of the active spot were analyzed to be o-hydroxy benzyl alcohol(saligenin), octanoic acid(caprylic acid), 9,12-cis-octadecadienoic acid(linoleic acid), 11-cis-octadecenoic acid(oleic acid), hexadecanoic acid(palmitic acid), 1H-indole-2-carboxylic acid and 1,2-benzenedicarboxylic acid(phthalate) in GC/Mass spectrum, and antimutagenicity of these active compounds using standard regeant was reconfirmed in S. typhimurium reversion assay.

• Clean Technology
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• v.27 no.4
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• pp.291-296
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• 2021

Recently, there has been increasing demand for advancing photocatalytic techniques that are capable of the efficient removal of organic pollutants in water. TiO₂, a representative photocatalytic material, has been commonly used as an effective photocatalyst, but it is rather expensive and an alternative is required that will fulfill the requirements of both high performing photocatalytic activities and cost-effectiveness. In this work, ZnO, which is more cost effective than TiO₂, was synthesized by using a microreactor-assisted nanomaterials (MAN) process. The process enabled a continuous production of ZnO nanoparticles (NPs) with a flower-like structure with high uniformity. In order to resolve the limited light absorption of ZnO arising from its large band gap, Ag NPs were uniformly decorated on the flower-like ZnO surface by using the MAN process. The plasmonic effect of Ag NPs led to a broadening of the absorption range toward visible wavelengths. Ag NPs also helped inhibit the electron-hole recombination by drawing electrons generated from the light absorption of the flower-like ZnO NPs. As a result, the Ag-ZnO nanocomposites showed improved photocatalytic activities compared with the flower-like ZnO NPs. The photocatalytic activities were evaluated through the degradation of methylene blue (MB) solution. Scanning electron microscopy (SEM), x-ray diffraction (XRD), and energy-dispersive x-ray spectroscopy (EDS) confirmed the successful synthesis of Ag-ZnO nanocomposites with high uniformity. Ag-ZnO nanocomposites synthesized via the MAN process offer the potential for cost-effective and scalable production of next-generation photocatalytic materials.