• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.107-114
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• 2024

In order to produce high-yield pitch-based activated carbon, pitch was synthesized by blending pyrolysis fuel oil (PFO) and coal-tar. Pitch was synthesized by varying the amount of coal-tar from 0~20% compared to PFO and reacting at 380~420 ℃ for 3 h. The synthesized pitch had a softening point between 80 and 260 ℃, and yields ranged from 10 to 40%. At all synthesis temperatures, as the coal-tar blending ratio increased, the yield increased and the softening point decreased. After considering the selected pitches (softening points: 230~260 ℃), pitches containing coal-tar were more volatile at a low boiling point and had a higher residual carbon content. This is a difference in the composition of coal-tar and PFO, and it was con- firmed that coal-tar has a lot of aromatics and PFO has a lot of aliphatics. The selected pitch was heated to 950 ℃ in a tubular reactor and physically activated with steam for 1 hour. Activated carbon containing coal-tar showed higher yield and microporosity compared to only PFO. In this study, the effect of increasing activated carbon yield by blending pitch raw materials was confirmed, and the physical activation characteristics according to the coal-tar mixing ratio were examined.

• Food Science and Preservation
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• v.30 no.3
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• pp.514-525
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• 2023

New types of vinegar drinks are being processed and developed using various raw materials. In this study, a beverage containing a mixture of 0.25% red ginseng extract and 5% Prunus mume fruit vinegar (RPV) was evaluated for its anti-fatigue effect on high-intensity exercised rats. RPV administration markedly enhanced running endurance and significantly decreased fatigue-related serum biomarkers, such as inorganic phosphate, ammonia, and L-lactate, compared to the other groups. In addition, RPV administration increased glycogen contents in the liver and muscles and decreased creatine kinase activity in the serum and muscles. RPV administration also remarkedly increased the activity of lactate in the muscles. Furthermore, HPLC analysis revealed that main organic acids in RPV were acetic acid, malic acid, and citric acids. Overall, the results indicate that RPV improved fatigue recovery in exhausted rats, thus proving a promising material of functional food to attenuate fatigue.

• Food Science and Preservation
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• v.30 no.5
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• pp.896-904
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• 2023

The texturization characteristics of textured vegetable protein (TVP) were investigated based on the extent of soybean decoating during the pretreatment of defatted soybean flour used for TVP. The raw materials for TVP consisted of 50% defatted soybean flour, 30% gluten, and 20% corn starch. The weight ratios of soybean seed coat to soybean flour were 9%, 6%, 3%, and zero. Extrusion was performed using an extruder equipped with a cooling die, maintaining a barrel temperature of 190℃ and screw speed of 250 rpm, Water was injected at a rate of 9 rpm using a metering pump. Regarding the textures of the extruded TVPs produced from defatted soybean flour, an increase in the soybean seed coat content led to a decrease in the apparent fibrous structural layer and an increase in hardness. However, there were no significant changes in elasticity and cohesion. Moreover, as the soybean seed coat content increased, the pH of TVPs decreased. A higher soybean seed coat content also tended to lower the moisture content, increasing water absorption, solids elution, and turbidity. These results suggest that an increased seed coat content reduces the proportion of protein, and the fibers present in the seed coats prevent texturization.

• Journal of Plant Biotechnology
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• v.50
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• pp.200-206
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• 2023

Although softwoods are widely distributed in Korea and used in various industries, studies are limited and comparative research on softwoods has been overlooked. Therefore, in this study, the physiological activity of four species of softwoods found in Korea was quantified. Needles and cones of Pinus densiflora, Chamaecyparis obtusa, Cryptomeria japonica, and Abies koreana were collected, and material was extracted using 70% methanol. We quantified the following physiological traits: total phenol and flavonoid content, antioxidant activity (DPPH, TEAC, FRAP), and inhibitory activity of the enzymes α-glucosidase, elastase, and tyrosinase. Total phenol and flavonoid contents and antioxidant activities were high in Chamaecyparis obtusa and Cryptomeria japonica, and α-glucosidase inhibition activity was highest in the leaves of Chamaecyparis obtusa. Elastase inhibitory activity was high in the leaves and cones of Pinus densiflora and the cones of Abies koreana, and tyrosinase inhibitory activity was highest in the leaves of Pinus densiflora. In Korea, softwoods are planted extensively on roadsides and as windbreaks, and they are highly competitive in supplying raw materials since they are pruned every year. Based on the results of this study, softwoods are considered suitable for use in healthcare products, diabetes products, wrinkles, and whitening cosmetics.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.258-265
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• 2023

After application of veterinary antibiotics, they may be partially metabolized before they are excreted by feces or urine either as unaltered form or as metabolites. Residual antibiotics enter the adjacent agricultural environments by spraying manure-based compost and liquid fertilizer on farmlands and lead to secondary pollution. The objective of this study was to compare the residual concentrations of 6 veterinary antibiotics by different production stages of liquid fertilizer from livestock manure recycling facilities. The relationship between concentration change of the residual antibiotics and the amount of liquid fertilizer component was also assessed. Pre-treatment showed the recovery of 63.4-106.7% at ppb level and the limit of quantification of 0.009-0.037 ㎍/L.As the result of analyzing the relationship between the residual concentrations of antibiotics and the amount of N component in liquid fertilizer by different production stages, the residual concentrations of antibiotics and N tended to decrease as the stabilization period elapsed during the liquid fertilization process. Average concentrations of sulfamethazine in raw materials, middle and final products of liquid fertilizer were 40.85, 26.17, 3.54 ㎍/L, respectively. Those of chlortetracycline decreased from 2.32 to 1.25 ㎍/L. The other 4 antibiotics also showed a decreasing trend by different production stages of liquid fertilizer. The amount of liquid fertilizer component N decreased from 0.21 to 0.096% by production stages of liquid fertilizer. It is considered that the correlation between residual antibiotic concentrations and N content can be applied as basic data for setting antibiotic reduction indicators.

• Journal of Electrochemical Science and Technology
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• v.15 no.4
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• pp.466-475
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• 2024

This research used solid waste from sugarcane production, named bagasse, as raw material for a functional carbon electrode. The bagasse was carbonized to produce carbon powder and, following activation with water vapor at 700℃. The activated carbon was doped with N and S to improve its electrochemical properties by treating it with thiourea precursor and heating it at 850℃ under nitrogen flow to produce N/S-doped carbon (NSCE). The produced carbon was then characterized to understand the specific diffraction pattern, molecular vibrations, and surface morphology. The result found that the NSCE showed two broad diffraction peaks at 23° and 43°, corresponding to [002] and [100] crystal planes following JCPDS75-1621. FTIR spectra showed some O-H, C-H, C-O, and C=C peaks. Peaks of C=N, C-N, and S-H demonstrate the presence of N/S within the NSCE. Raman analysis revealed that N/S doping caused structure defects within the single C6 layer networks, providing carbon vacancies (V_C^••••) because of C replacement by N (N'_C) and S (S"_C). Meanwhile, XPS analysis showed N/S introduction to the C network by revealing peaks at 168.26 eV and 169.55 eV, corresponding to S2p_3/2 and S2p_1/2, and 171.95 eV corresponds to C-SO₃-C, indicating the presence of S within the thiol group attached to the carbon. Meanwhile, N1s are revealed at 402.4 eV and 405.5 eV, confirming pyrrolic nitrogen (N-5) and quaternary nitrogen (N-Q). The electrochemical analysis found that the reaction within the prepared-NSCE/NaClO₄/Na was reversible, with an onset potential of 0.1 V vs. Na/Na⁺, explaining the intercalation and deintercalation of sodium ions. The sodium battery full cell showed an excellent battery performance with an initial charging-discharging capacity of 720 mAh g^-1 and 570 mAh g^-1, respectively, at 0.2C. Meanwhile, a cycling test showed the average Coulombic efficiency of 84.4% and capacity retention of 57% after 50 cycles.

• Food Engineering Progress
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• v.31 no.4
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• pp.312-321
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• 2019

The Lao PDR is a developing country that heavily relies on rice farming. During off-season of rice farming, rural villagers produce non-timber forest products such as bamboo products. Until recently many villages have overexploited bamboo resources and supplied raw bamboo materials to foreign companies. Although the Lao government allocated harvesting quotas, most villagers keep on cutting bamboos due to no other income during the off-season. This study provides an alternative income model, bamboo handicraft, that can increase villagers' income while minimizing the use of bamboo resources. It also accesses the economic feasibility of the new income model for a mountain village, Nongboua village, where surveys were conducted on general incomes of 10 sample families who participated in the new income model voluntarily. A difference was made during the off-season when the sample families worked on cutting bamboos (previous income) or bamboo handicrafts (new income). A daily wage of $ 11.5 was used for the previous income, based on our surveys. For the new income, it was assumed that single family could produce 6 bamboo handicrafts daily with a unit price of $ 2.3, resulting in a daily income of $ 13.8. During the off-season, 8 and 14 working days in a month were assumed for the previous and new incomes based on surveys. Then the previous previous and new yearly incomes were estimated and compared using normality and paired t-tests. This study found that the new yearly income was significantly greater than the previous yearly income (p < 0.001): the former (rice farming and bamboo handicraft, $ 2,064) was 42% ($ 608) greater than the latter (rice farming and bamboo cutting, $ 1,456). These results suggested that the new income model could increase villagers' income significantly. If the bamboo handicraft model is applied for other areas with bamboo resources, it can provide an opportunity to improve the rural economies and livelihoods of developing countries.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.110-118
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• 2010

Supercritical treatment of liquefaction technology for rice hull was investigated the biomass conversion rate and evaluated its crude oil in respect to feasibility of burner in order to heat the green house. The reaction was carried out in a 5,000 mL liquefaction system with dispenser and external electrical furnace. Raw materials (160 g) of rice hull and 3,000 mL of different solvents were fed into the reactor. It was observed that the maximum crude oil yield was about 84.4 % with 1-butanol. The calorific value of crude oil from ethanol solvent were 7,752 kcal/kg. Furthermore, in case study of co-solvent with ethanol and bulk-glycerol, it observed that more than 80 % of rice hull was decomposed and liquefied in its solvent at $315{\sim}326^{\circ}C$ for 30 min. For the development of applicable bio-fuel from rice hull, it was considered that its feasibility is necessary to be carried out for co-solvent soluble portions. Regarding to utilize the crude oil into burner as fuel, it was observed that its calorific value was lower at approximately 24 % than the diesel. Also, flame length from crude oil at lower temperature was decreasing due to incomplete incineration. The temperature of warm wind on the burner was maintained between 63 and $65^{\circ}C$, and the temperature of emission line was appeared at $350{\sim}380^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.104-109
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• 2010

Hydro-thermal liquefaction technology for rapeseed straws was investigated the biomass conversion rate with different catalysts and reaction temperatures. NaOH and KOH were used for catalysts, and the reaction temperature were ranged from 180 to $320^{\circ}C$ at every $20^{\circ}C$ of intervals for 10 minutes. The reaction was carried out in a 5,000 mL liquefaction system with dispenser and external electrical furnace. Raw materials (160g), 2,000 mL of distilled water and 10% (wt/wt) of catalyst to plant residue were fed into the reactor. It was observed that the maximum crude oil yield was about 36% at temperature range, $260{\sim}280^{\circ}C$ with KOH and at $300^{\circ}C$ with NaOH, respectively. It was observed that the more calorific values of crude oil, the higher reaction temperature with KOH, but it had the reverse pattern in NaOH.

• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.3
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• pp.114-124
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• 2024

Purpose: This study analyzed raw data from the 2022 Korean Community Health Survey (KCHS) to explore the relationship between physical activities and the mental health of middle-aged individuals, and examined factors influencing chewing discomfort. Materials and Methods: Data pertaining to 104,500 middle-aged people aged between 40 and 64 were analyzed. The variables analyzed included general characteristics, perceived level of health, level of oral health, physical activities, mental health (PHQ-9), and status of chewing discomfort. Cross-analysis was conducted to explore the differences in general characteristics, physical activities, mental health factors, and chewing discomfort status. Meanwhile, logistic regression analysis was performed on factors influencing chewing discomfort. Results: It was observed that chewing discomfort was more severe for middle-aged individuals who reported that their oral health level was neither good nor poor compared with those who reported that their oral health was good (OR: 8.443, P < 0.001), those who reported that their perceived level of health was poor (OR: 49.173, P < 0.001), those who reported not performing the walking exercise (OR: 1.354, P < 0.001), those who reported that they had suicidal ideation compared with those who did not (OR: 2.543, P < 0.001), those who reported that they had made a suicidal attempt compared with those who had not (OR: 4.456, P < 0.001), and those who reported that their level of depression was severe or more serious (OR: 4.624, P < 0.001). Conclusion: In middle-aged individuals, physical activities and mental health needs to be considered as a risk factor in the improvement of oral health.