• Safety and Health at Work
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• v.2 no.4
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• pp.365-374
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• 2011

Objectives: This study was designed to investigate whether long-term, low-level exposure to monocyclic aromatic hydrocarbons (MAHs) induced insulin resistance. Methods: The subjects were 110 male workers who were occupationally exposed to styrene, toluene, and xylene. One hundred and ten age-matched male workers who had never been occupationally exposed to organic solvents were selected as a control group. Cytokines, which have played a key role in the pathogenesis of insulin resistance, and oxidative stress indices were measured. Assessment of exposure to MAHs was performed by measuring their ambient levels and their urinary metabolites in exposed workers, and the resulting parameters between the exposed group and non-exposed control groups were compared. Results: There was no significant difference in general characteristics and anthropometric parameters between the two groups; however, total cholesterol, fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance levels were significantly higher in the exposed group. Phenylglyoxylic acid levels showed significant association with tumor necrosis factor-${\alpha}$, total oxidative status, and oxidative stress index via multiple linear regression analysis. Further, there was a negative correlation between methylhippuric acid levels and total anti-oxidative capacity, and there was a significant relationship between MAHs exposure and fasting glucose levels, as found by multiple logistic regression analysis (odds ratio = 3.95, 95% confidence interval = 1.074-14.530). Conclusion: This study indicated that MAHs increase fasting glucose level and insulin resistance. Furthermore, these results suggested that absorbing the organic solvent itself and active metabolic intermediates can increase oxidative stress and cytokine levels, resulting in the changes in glucose metabolism and the induction of insulin resistance.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.157-168
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• 2018

Recently, the occurrence of typhoons and heavy rainfall is increasing due to climate change. This causes increase in possibility of landslide damages in rural areas. However, in reality, the precise engineering stability assessment studies are still insufficient. Therefore, in order to reduce the landslide damages and effectively manage mountainous areas, the development of disaster prevention techniques is needed. In this study, to analyze the shock absorbing effect of the buffer-spring during application of dynamic impact load in the debris flow protection system, numerical analysis is carried out for each free field of the buffer-spring and the load sharing ratio of the buffer-spring is also examined. In addition, the field applicability is verified by comparison of the tensile strength of the conventional buffer-spring and the wedge type buffer-spring on various magnitudes of dynamic impact load. As a result of the study, it is found that the net-type debris protection system is effective to mitigate loss of properties and human lifes during landslide.

• Food Science of Animal Resources
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• v.38 no.6
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• pp.1189-1195
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• 2018

This study developed an antimicrobial hydrogel to control Listeria monocytogenes in Yukhoe (Korean beef tartare). Four hydrogels (hydrogel 1: 5% alginate+1% chitosan+0.2% $CaCl_2$, hydrogel 2: 1% ${\kappa}$-carrageenan+1% chitosan, hydrogel 3: 2% ${\kappa}$-carrageenan+1% $CaCl_2$, and hydrogel 4: 2% ${\kappa}$-carrageenan+3% $CaCl_2$) were prepared. The hydrogels then absorbed 0.1% grapefruit seed extract (GSE) and 0.1% citrus extract (CE) for 30, 60, 120, and 240 min to be antimicrobial hydrogels. To select the most effective antimicrobial hydrogel, their swelling ratio (SR) and antilisterial activities were determined. The selected hydrogel ($2{\times}2cm$) was then placed on surface of beef (round; $3{\times}3cm$), where L. monocytogenes (ca. $10^6CFU/g$) were inoculated, and the cell counts were enumerated on PALCAM agar. Among the hydrogels, the SR of hydrogel 1 increased with absorbing time, but other hydrogels showed no significant changes. Antimicrobial hydrogel 1 showed higher (p<0.05) antilisterial activity than other antimicrobial hydrogels, especially for the one absorbed the antimicrobial for 120 min. Thus, the antimicrobial hydrogel 1 absorbed antimicrobials for 120 min was applied on raw beef at $4^{\circ}C$, and reduced (p<0.05) more than 90% of L. monocytogenes on raw beef. These results indicate that antimicrobial hydrogel 1 formulated with 0.1% GSE or 0.1% CE is appropriate to improve the safety of Yukhoe by reducing psychrotrophic L. monocytogenes cell counts on raw beef.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.3
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• pp.31-41
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• 2019

More than 90% of roadway in the world are paved as asphalt concrete pavement due to its excellent properties compared with other paving materials; excellent riding quality, flexibility, anti-icing property and easy maintenance-ability. In this study, to make best use of the softer property of the asphalt mixture, the flexible sand asphalt mixture (FSAM) was developed for pedestrian ways. The mix design was conducted to prepare FSAM using PG64-22 asphalt, screenings (sand) less than 5mm, crumb rubber, hydrated lime and limestone powder without coarse aggregate. The deformation strength ($S_D$), indirect tensile strength (ITS) and tensile strength ratio (TSR) tests were conducted to make sure durability of FSAM performance. The impact energy absorption and flexibility were measured by drop-boll test and the resilient modulus ($M_R$) test. The impact energy absorption of FSAM was compared with normal asphalt pavement, concrete pavement, stone and concrete block for pedestrian way. As a result of drop-boll test, FSAM showed higher impact energy absorption compared with other paving materials with the range of 18% to 43%. Impact energy absorption of FSAM increased with increasing test temperature from 5 to $40^{\circ}C$. The results of $M_R$ test at $5^{\circ}C$ showed that the flexibility of FSPA was increased further, because the $M_R$ value of the sand asphalt was measured to be 38% lower than normal dense-graded asphalt mixture (WC-1). Therefore, it was concluded that the FSAM could provide a high impact absorbing characteristics, which would improve walking quality of the pedestrian ways.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.300-308
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• 2021

In this study, 3D networked poly(sodium acrylate) gel was polymerized and controlled with the crosslinking environment to evaluate the mechanical properties and swelling behavior. In general, as the degree of crosslinking in a pre-gelled solution increases, the swelling ratio of the 3D networked gel decrease while the mechanical strength of the gel increases. Interestingly, this study demonstrates that the polymerization and crosslinking efficiency in gelling process could be depended on the crosslinking environment by evaluating the number of elastically cross-links in 3D networked gel. As a result, the number of elastically corss-links would be changed with 3.6 times as varying of the crosslinking environment while keeping the degree of crosslinking. It is expected that the 3D networked gel would be optimized as an effective absorbing agent for VOCs by using the gel evaluation method based on the number of elastically cross-links.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.950-957
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• 2023

Purpose: The response technology is needed to prevent the spill of highly toxic oil contaminants in advance. Therefore, this paper described the results of an experimental study to predict the engineering properties of the developed reactive material. Method: Compaction tests and spectral information acquisition experiments were conducted on the reactive materials, and the results were evaluated. In addition, the correlation between spectral information and maximum dry unit weight was analyzed to evaluate the possibility of predicting the engineering properties for reactive materials. Result: The compaction test results showed that the maximum dry unit weight was in the range of approximately 9kN/m³ to 10kN/m³. The spectral information confirmed that the maximum reflectance decreased as the polynorbornene decreased. Conclusion: It was confirmed that the maximum dry unit weight of the reactive material for absorbing oil contaminants can be predicted using the maximum reflectance according to the component ratio of the reactive material.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.99-105
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• 2015

PURPOSES: In this study, alkali-activated blast-furnace slag (AABFS) was investigated to determine its capacity to absorb carbon dioxide and to demonstrate the feasibility of its use as an alternative to ordinary Portland cement (OPC). In addition, this study was performed to evaluate the influence of the alkali-activator concentration on the absorption capacity and physicochemical characteristics. METHODS: To determine the characteristics of the AABFS as a function of the activator concentration, blast-furnace slag was activated by using calcium hydroxide at mass ratios ranging from 6 to 24%. The AABFS pastes were used to evaluate the carbon dioxide absorption capacity and rate, while the OPC paste was tested under the same conditions for comparison. The changes in the surface morphology and chemical composition before and after the carbon dioxide absorption were analyzed by using SEM and XRF. RESULTS: At an activator concentration of 24%, the AABFS absorbed approximately 42g of carbon dioxide per mass of paste. Meanwhile, the amount of carbon dioxide absorbed onto the OPC was minimal at the same activator concentration, indicating that the AABFS actively absorbed carbon dioxide as a result of the carbonation reaction on its surface. However, the carbon dioxide absorption capacity and rate decreased as the activator concentration increased, because a high concentration of the activator promoted a hydration reaction and formed a dense internal structure, which was confirmed by SEM analysis. The results of the XRF analyses showed that the CaO ratio increased after the carbon dioxide absorption. CONCLUSIONS : The experimental results confirmed that the AABFS was capable of absorbing large amounts of carbon dioxide, suggesting that it can be used as a dry absorbent for carbon capture and sequestration and as a feasible alternative to OPC. In the formation of AABFS, the activator concentration affected the hydration reaction and changed the surface and internal structure, resulting in changes to the carbon dioxide absorption capacity and rate. Accordingly, the activator ratio should be carefully selected to enhance not only the carbon capture capacity but also the physicochemical characteristics of the geopolymer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1484-1490
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• 2006

This study was carried out to prepare spaghetti sauce with adductor muscle of pearl oyster (SSAM) and to compare with commercial spaghetti sauce (CSS). From the results of organic acid, pH, hunter color value and sensory evaluation, the optimal addition ratio of adductor muscle of pearl oyster was 11% based for preparing SSAM and reasonable $F_0$ value was about 4 min for keeping storage of SSAM. The proximate composition of SSAM was 69.8% for moisture, 3.7% for protein, 4.2% for crude lipid and 3.4% for crude ash. SSAM was superior in sensory flavor and texture to CSS. There was, however, no significant difference (p<0.05) in sensory color between CSS and SSAM. The total amino acid content (3,033.4 mg/100 g) of SSAM was higher than that (2,305.7 mg/100 g) of CSS and the major amino acids were aspartic acid, glutamic acid, leucine and lysine. Calcium and phosphorus contents in SSAM were 48.5 mg/100 g and 27.1 mg/100 g, respectively. Calcium level based on phosphorous was 1.78, which was a good ratio for absorbing calcium. The free amino acid content and taste value of SSAM were 989.4 mg/100 g and 141.04 mg/100 g, respectively These results suggested that the major taste active compounds among free amino acid were glutamic acid and aspartic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.93-99
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• 2007

The study was carried out to prepare spaghetti sauce with oyster (SSO) and the food components characteristics of the SSO were also compared to those of commercial spaghetti sauces (CSS). The optimal addition ratio of oyster for preparing SSO was 11% based on 100 g of SSO according to the results of organic acid content, Hunter color value, viscosity, and sensory evaluation. The reasonable $F_0$ value for the keeping storage of SSO was about 4 min. The proximate composition of SSO prepared under the optimal processing condition was 71.2% moisture, 2.8% protein, 6.9% crude lipid, and 3.2% crude ash. The results of sensory evaluation suggested that the quality of SSO was superior to that of CSS. However, there was no significant difference (p<0.05) in sensory evaluation on color between CSS and SSO. The total amino acid content (2,532.2 mg/100 g) of SSO was higher than that of CCS (2,305.7 mg/100 g). The contents of calcium and phosphorus of SSO were 25.7 mg/100 g and 48.7 mg/100 g, respectively. The calcium content/phosphorus content showed a suitable ratio for absorbing calcium. The total free amino content and the taste value were 1,040.2 mg/100 g and 151.26, respectively. The major taste-active amino acids were glutamic acid and aspartic acid.

• Journal of Korean Society of Forest Science
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• v.45 no.1
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• pp.26-36
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• 1979

Through several trials that has done for making the fertilizing-counter plan on the soil improving species, some results have been got as follows; 1. In the non-phosphorus dressing plots soil improving species have very poor survial ratio and show us to be died step by step. It may be resons that root can not make the nodule in case of non-phosphorus dressing and so tree could not absorb the nitrogen nutrient fixed by the nodule. And root competition with the weedy speces for utilizing the nutrient and oxygen in the soil could be reasons when planting in the heavy weedy rooting site. 2. Triple super phosphate, Fused Mg Phosphate and Fused super phosphate have showed the remarkable effects on the growth of soil improving species within 3rd year after planting. But Koreaan tablet fertilizer(9-12-4) for forest purpose have reacted considerably lower effect in comparision with the above powder and grain type phosphorous fertilizer. 3. In case of tablet type fertilizer tree root will have very little phosphorus absorbing surface because phosphorus can be utilized only from the tablet surface and root can not penetrate into the tablet. This my be reson to show the poor dressing reaction of tablet fertilizer but tablet fertilizer has a possibility to be utilized during long years as a sympton in photo 6. So tablet fertilizer can have a recommendation to dress much fertilizer at p]anting year and then tree root can get much more chance for absorbing the phosphorus that could keep the high survival and for utilizing it during many years without after dressing. 4. The granurar and powder type phosphate can develop the dense root mat like photo 8 because of giving the large surface for absorbing the phosphorus and weedy root can approch to the nodule for taking the nitrogen element. So this type seems to present better effect than tablet type to control the soil movement, stem weight as 200g per meter(l meter long${\times}$0.1m width). When added the lime any effect could not be found and rather give the negative effect. So Lespedeza seed sowing and phosphorus dressing system seems us to be very reasonable method for covering the raw material of basket making, fodder and fuel wood supply. 7. Fused Mg phosphate and Fused super phosphate are good fertilizer to the soil improving species and dressing more than 30g per seedling can be recommendable amount. 5. In the unproductive and dry soil with phosphorus fertilizer Robinia pseudoacacia and Alnus firnui can grow more than 2.3m in height at 3rd year and Alnus inokumae have the rapid height growth that is more than 1.8m at 2nd year. Depending on the growth situation like the above example minirotated management has possibilities and rapid covering of erosed land can be done with the soil improving species and phosphorus fertilizer. 6. In the Lespedeza sowing plot with 40g Fused Mg phosphate dressing per meter in the eroded and unproductive forest soil Lespedeza have completely covered this poor land and produced the green.