• Advances in nano research
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• v.13 no.5
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• pp.417-426
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• 2022

Bisphenol A (BPA) is one of the chemicals used in monomer epoxy resins and polycarbonate plastics. The surface-enhanced Raman spectroscopy (SERS) method is precise for identifying biological materials and chemicals at considerably low concentrations. In the present article, the substrates coated with gold nanoparticles have been studied to identify BPA and control the diseases caused by this chemical. Gold nanoparticles were made by a simple chemical method and by applying gold salt and trisodium citrate dihydrate reductant and were coated on glass substrates by a spin-coat approach. Finally, using these SERS substrates as plasmonic sensors and Raman spectroscopy, the Raman signal enhancement of molecular vibrations of BPA was investigated. Then, the molecular vibrations of BPA in some consumer goods were identified by applying SERS substrates as plasmonic sensors and Raman spectroscopy. The fabricated gold nanoparticles are spherical and quasi-spherical nanoparticles that confirm the formation of gold nanoparticles by observing the plasmon resonance peak at 517 nm. Active SERS substrates have been coated with nanoparticles, which improve the Raman signal. The enhancement of the Raman signal is due to the resonance of the surface plasmons of the nanoparticles. Active SERS substrates, gold nanoparticles deposited on a glass substrate, were fabricated for the detection of BPA; a detection limit of 10-9 M and a relative standard deviation (RSD) equal to 4.17% were obtained for ten repeated measurements in the concentration of 10-9 M. Hence, the Raman results indicate that the active SERS substrates, gold nanoparticles for the detection of BPA along with the developed methods, show promising results for SERS-based studies and can lead to the development of microsensors. In Raman spectroscopy, SERS active substrate coated with gold nanoparticles are of interest, which is larger than gold particles due to the resonance of the surface plasmons of gold nanoparticles and the scattering of light from gold particles since the Raman signal amplifies the molecular vibrations of BPA. By decreasing the concentration of BPA deposited on the active SERS substrates, the Raman signal is also weakened due to the reduction of molecular vibrations. By increasing the surface roughness of the active SERS substrates, the Raman signal can be enhanced due to increased light scattering from rough centers, which are the same as the larger particles created throughout the deposition by the spin-coat method, and as a result, they enhance the signal by increasing the scattering of light. Then, the molecular vibrations of BPA were identified in some consumer goods by SERS substrates as plasmonic sensors and Raman spectroscopy.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.51-60
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• 2024

Hi Air Korea and Hanwha ocean are currently developing an Onboard Carbon dioxide Capture System (OCCS) to absorb CO₂ emitted from ship's engine using a sodium hydroxide(NaOH) solution, and converting the resulting salt into a solid form through a chemical reaction with calcium oxide (CaO). The system process involves the following steps; 1)The reaction of CO₂ gas absorption in water, 2)The reaction between carbonic acid (H₂CO₃) and NaOH solution to produce carbonate or bicarbonate, and 3)The reaction between carbonate or bicarbonate and CaO to form calcium carbonate (CaCO₃). And ultimately, the solid material, CaCO₃, is separated and discharged using a separator. The OCCS has been installed on an ship and the test results have confirmed significant reduction effects of CO₂ in the ship's exhaust gas. A portion of the exhaust gas emitted from the engine was transferred to the OCCS using a blower. The flow rate of the transferred gas ranged from 800 to 1384 m³/hr, and the CO₂ concentration in the exhaust gas was 5.1 vol% for VLSFO, 3.7 vol% for LNG and a 12 wt% NaOH solution was used. The results showed a CO₂ capture efficiency of approximately 42.5 to 64.1 vol% and the CO₂ capture rate approximately 48.4 to 52.2kg/hr. Additionally, to assess the impact of the discharged CaCO₃on the marine ecosystem, we conducted "marine ecotoxicity test" and performed Computational Fluid Dynamics (CFD) analysis to evaluate the dispersion and dilution of the discharged effluent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1438-1446
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• 2016

The objectives of this study were to investigate the effects of superheated steam (SHS) treatment on the physicochemical and microbial properties of garlic. The garlic was treated by SHS at temperatures of 100, 150, 200, 250, 300, and $350^{\circ}C$ for 60 s. The moisture content of raw garlic was lower than that of SHS-treated garlic. The total thiosulfinate and pyruvate contents were dramatically reduced by SHS treatments. The antioxidant activities of garlic measured by ferric reducing/antioxidant power, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging assay, and total phenolics content decreased by SHS. The major volatile sulfur compounds of garlic such as diallyl disulfide, allicin, allyl sulfide, diallyl sulfide, and diallyl trisulfide were significantly reduced by SHS. The antimicrobial effects of raw garlic were stronger than those of SHS-treated garlic against three strains of bacteria, including Staphylococcus aureus, Escherichia coli, and Bacillus cereus. However, total aerobic bacteria in garlic were dramatically reduced by SHS from 8.6 to 2.9 log CFU/g. The results from the sensory evaluation show that SHS treatment of garlic above $200^{\circ}C$ provides better acceptably due to reduction of off-flavor and pungency of garlic. These results suggest that superheated steam treatment can used as an efficient process for reducing garlic off-flavor and pungency.

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.922-928
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• 2010

There is a little information on the effect of calcium cloride ($CaCl_2$) which is used as deicing salt in Korea on the physiological responses of the street trees. Prunus sargentii is one of the most widespread tree species of street vegetation in Korea. In this study, the effect of $CaCl_2$ on photosynthetic apparatus such as chlorophyll fluorescence image and light response curve of P. sargentii in relation to their leaf and root collar growth responses were investigated. To study the effect of $CaCl_2$ treatment in the early spring, we irrigated twice in rhizosphere of P. sargentii (3-year-old) planted plastic pots with solution of 0.5%, 1.0%, 3.0% $CaCl_2$ concentration before leaf expansion. Results after treatments, total chlorophyll contents and the chlorophyll a/b, photosynthetic rate, quantum yield, dark respiration decreased with increasing $CaCl_2$ concentration. On the contrary, light compensation point increased with increasing $CaCl_2$ concentration. Through the linear regressions of correlation of photosynthetic rate with photosynthetic parameters (quantum yield, dark respiration and light compensation point), we found a significant relationship (p<0.05) between photosynthetic rate and quantum yield and light compensation point except dark respiration. Calcium cloride ($CaCl_2$) induced inhibition of photochemical efficiency ($F_v/F_M$) and non-photochemical quenching (NPQ) were found in treatments of $CaCl_2$, and these reduction rates between control and CaCl2 treatments were drastically showed at 80 days. We suggest that physiological activities are limited from treatment of $CaCl_2$. These reductions of photosynthetic apparatus ability caused eventually the reduction of leaf and diameter at root collar growth.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.275-280
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• 2015

The objective of this study was to investigate the effect of drip irrigation level on soil salinity and growth of broccoli (Brassica oleracea L. var. italica) at the 'Saemangeum Reclaimed Tidal Land' from April to June, 2015. Drip irrigation was conducted at 1.5, 3.0 and $6.0mm{\cdot}day^{-1}$ level for reduction of resalinization in the plastic vinyl house using 10cm spacing drip irrigation tape. At harvesting stage, the average EC of surface soil was $10.9dS{\cdot}m^{-1}$ for $1.5mm{\cdot}day^{-1}$, $11.5dS{\cdot}m^{-1}$ for $3.0mm{\cdot}day^{-1}$ and $5.1dS{\cdot}m^{-1}$ for $6.0mm{\cdot}day^{-1}$ and was significantly reduced by 52~56% in $6.0mm{\cdot}day^{-1}$ treated plot compared to those in 1.5 and $3.0mm{\cdot}day^{-1}$ plots. The fresh bud weights of 1.5, 3.0 and $6.0mm{\cdot}day^{-1}$ treatment plots were 60.9, 129.1 and $371.3g{\cdot}plant^{-1}$, respectively. The estimated soil EC for 50% yield reduction was $7.6dS{\cdot}m^{-1}$ and the desalinization depth by drip irrigation was 30~40cm in soil profile. The total amount of drip irrigation water was estimated to be 422mm and the daily drip irrigation level was $6.0mm{\cdot}day^{-1}$ for the prevention of resalinization during the broccoli growing period at the 'Saemangeum Reclaimed Tidal Land'. Our results suggested that drip irrigation shows effectiveness on the lowering the soil salinity according to the drip irrigation quantity but it needs more research on this study because dynamics of salts in soil can vary with many factors such as soil physico-chemical properties and seasonal climate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1243-1252
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• 2017

There are limited programs for low sodium intake based on the nutrition education model for housewives who cook family meals. The objective of this study was to evaluate the effects of model-based nutrition programs for low sodium intake among housewives residing in Seoul by incorporating social cognitive theory. A questionnaire survey before and after education was conducted on 140 housewives who participated in the 'Low Sodium Nutritional Education Program' delivered by a district public health center for 12 weeks from November 2015 to January 2016. The contents of the nutrition education program and program evaluation items were based on the action plans for 'Less Sodium Healthy Practice' suggested by the Ministry of Food and Drug Safety. The results show that program participants showed a lower preference for sodium, higher selection of low sodium dishes from restaurants or cafeteria if available, and increased awareness of the need of restaurants to serve low sodium dishes compared to before. In terms of behavioral changes, there were significant improvements in checking nutrition labeling and selection of foods with low sodium, use of low sodium food products, use of natural seasonings to reduce salt intake, and consumption of fast foods and processed foods. On the other hand, requesting less salty meals when ordering and introducing restaurants or cafeterias with healthy and low sodium menus turned out to be difficult to put into practice. In conclusion, the nutrition education program for sodium intake reduction for housewives was effective in increasing knowledge, environment recognition, and behaviors related to low sodium intake but not behaviors related to physical environmental factors. Therefore, further nutrition education programs and practices for sodium intake reduction should be comprehensively implemented with improvement of physical environments for low sodium intake.

• Journal of Life Science
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• v.32 no.7
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• pp.578-587
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• 2022

Korea, as the world's 7^th largest emitter of greenhouse gases, has raised the national greenhouse gas reduction target as international regulations have been strengthened. As it is possible to utilize coastal and marine ecosystems as important nature-based solutions (NbS) for implementing climate change mitigation or adaptation plans, the blue carbon ecosystem is now receiving attention. Blue carbon refers to carbon that is deposited and stored for a long period after carbon dioxide (CO₂) is absorbed as biomass by coastal ecosystems or oceanic ecosystems through photosynthesis. Currently, there are only three blue carbon ecosystems officially recognized by the Intergovernmental Panel on Climate Change (IPCC): mangroves, salt marshes, and seagrasses. However, the results of new research on the high CO₂ sequestration and storage capacity of various new blue carbon sinks, such as seaweeds, microalgae, coral reefs, and non-vegetated tidal flats, have been continuously reported to the academic community recently. The possibility of IPCC international accreditation is gradually increasing through scientific verification related to calculations. In this review, the current status and potential value of seaweeds, seagrass fields, and non-vegetated tidal flats, which are sources of blue carbon on the east coast, are discussed. This paper confirms that seaweed resources are the most effective NbS in the East Sea of Korea. In addition, we would like to suggest the direction of research and development (R&D) and utilization so that new blue carbon sinks can obtain international IPCC certification in the near future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.269-276
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• 2016

This study was conducted to determine the inactivation effects of slightly acidic electrolyzed water (SAEW) on microorganisms attached to salted Chinese cabbage and food materials of kimchi, such as slice radish and green onion. In addition, changes in microbial and physicochemical quality of manufactured kimchi during storage at $4^{\circ}C$ for 4 weeks were investigated. Compared to the untreated control with tap water, total bacterial counts (TBC) of Chinese cabbage, slice radish, and green onion were reduced by 1.75, 1.68, and 1.03 log CFU/g at dipping times of 20 min, 5 min, and 10 min, respectively, upon treatment with 30 ppm SAEW at $40^{\circ}C$. Effect of microbial inhibition was higher in salted Chinese cabbage brined in 10% salt (w/v) of 30 pm SAEW at $40^{\circ}C$ than in untreated control with tap water, as indicated by 1.00 log CFU/g reduction. TBC of kimchi manufactured with materials treated with 30 ppm SAEW at $40^{\circ}C$ was not significantly affected compared to untreated control, although coliforms were remarkably reduced compared to the untreated control. At the beginning of storage (1 weeks), TBC and lactic acid bacteria (LAB) counts increased by approximately 9 and 7.66~8.18 log CFU/g, respectively, and coliforms were completely eliminated. The pH and acidity of kimchi at 2 weeks were 4.34~4.49 and 0.55~0.66%, respectively, and then slowly decreased. The texture (firmness) of kimchi decreased with storage time, but the difference was not significant. This combined treatment might be considered as a potentially beneficial sanitizing method for improving the quality and safety of kimchi.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.163-170
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• 2001

Purpose : The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Materials and Methods : Four human cancer cell lines - PCI-1, SNU-1066, NCI-H630 and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy. For clonogenic assay, cells in $25\;cm^2$ flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for $10\~14$ days. For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. Results : There was minimal variation in the values gained from these two methods with the standard deviation generally less than $5\%$, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the $R^2$ value of $0.975\~0.992$ between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than $30\%$). For cells with low plating efficiency (less than $30\%$), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was after 6 doubling times for the results compatible with those of clonogenic assay, at least after 4 doubling times was required for valid results. In consideration of practical limits of assay (12 days, in this study) cells with doubling time more than 3 days were inappropriate for application. Conclusion : In conclusion, it is found that MTT assay can successfully replace clonogenic assay of tested cancer cell lines after irradiation only if MTT assay was undertaken with optimal assay conditions that included plating efficiency of each cell line and doubling time at least.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.541-549
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• 2008

Background: Vasoconstrictor-induced reduction in arterial graft diameter can cause significant flow deprivation. The aim of this study was to evaluate the effect of vasodilator pretreatment on vasoconstrictor-induced blood vessel spasm in vitro. Material and Method: Rabbit brachial arteries (BA) and celiac arteries (CA) were cut into rings $(3{\sim}4mm)$ and suspended with a force displacement transducer (TSD $125C^{(R)}$, Biopac Inc. USA) in a tissue bath filled with 5 mL modified Krebs solution bubbled with 5% $CO_2$ and 95% $O_2\;at\;38^{\circ}C$. The rings were contracted with vasoconstrictors, and the developed tension changes were considered control values. The rings were then pre- treated with $30{\mu}M$ nitroglycerin, nicardipine, verapamil, and papaverine, respectively, for 40 minutes and rinsed with the physiologic buffered salt solution three times every 15 min. The vasoconstrictor-induced tension changes after the previous procedure were considered experimental values. Data are expressed as the percentage tension induced by vasoconstrictors before and after pretreatment with vasodilators. Result: Nicardipine depressed vasoconstriction induced by norepinephrine, angiotensin II (All), and U46619 in both the BA and the CA more significantly than did nitroglycerin (p<0.01) and verapamil (p<0.05). Verapamil depressed vasoconstriction induced by 5-hydroxytryptamine (5HT), All, and U46619 in the BA and by 5HT in the CA more significantly than did nitroglycerin (p<0.01). Conclusion: These findings suggest that both nicardipine and verapamil effectively depressed vasoconstrictor action. Nicardipine is thought to be more effective than verapamil for the prevention of vasoconstrictor action.