• Journal of the Korean Society of Safety
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• v.38 no.4
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• pp.32-38
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• 2023

Job stress factors are factors that induce biological, psychological, and behavioral responses in individuals when they encounter mental and physical stimuli in the workplace. According to occupational safety and health standards, employers are responsible for the health consequences of job stress when workers engage in activities that result in high levels of physical fatigue and mental stress. Such activities include long working hours, shift work (including night shifts), driving vehicles, and operating precision machinery. Therefore, precautionary measures should be implemented. Following the COVID-19 epidemic, the logistics industry in Korea has experienced rapid growth owing to the shift from offline to online platforms facilitated by advanced digital infrastructure. Consequently, this study conducted a survey to analyze job stress factors among delivery workers. The survey utilized a Korean job stress factor assessment tool comprising 43 items and analyzed job stress factors considering the work characteristics of the courier business field obtained from responses provided by 421 courier workers nationwide. The survey analysis revealed that the physical environment, job demands, and job autonomy exhibited higher stress indices among Korean workers. Furthermore, the younger the age, the higher the stress on job demands, whereas the higher the age, the higher the stress on relationship conflict, job instability, and workplace culture. In addition, daytime delivery work was associated with higher stress levels in job demands and job instability compared with nighttime delivery work. These findings can serve as foundational data for reducing and preventing job stress among courier workers, whose workload has increased owing to the growth of the logistics industry.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.1-22
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• 2016

In this study, the securing state of nationally indicated beneficial microbial resources was evaluated in an aspect of bio-diversity using their taxonomical information. Depending on the analysis result with the Margalef's richness or the Mehinick's index which are representative bio-diversity analytical indices, species diversity values was revealed as 8.537, 3.546 within bacterial resources, 3.349, 2.167 within fungal resources. Several developed or researched beneficial strains and spoilage microbes showed relative taxonomical relationship with comparation of their biological information. As a result, we propose the necessity or countermeasure method for preventing the microbial spoilage with the overhauling consideration of advanced research on agricultural microbiology covering crop endophyte beneficial/spoilage microorganisms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.861-869
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• 2023

This study aimed to evaluate the effectivity of full-fat black soldier fly Hermetia illucens (BSF) and defatted mealworm Tenebrio molitor (MW) larvae meal as a fish meal (FM) substitute in a low-fish meal (LFM) diet for juvenile olive flounder Paralichthys olivaceus. The LFM diet comprising 45% FM with tankage meal, poultry byproduct meal, soy protein concentrate and wheat gluten was the control diet. Three experimental diets were 10% FM in Con with BSF, MW and a mixture of both at the same ratio (designated as B10, M10 and B5M5, respectively). Four hundred and forty-fourth juvenile P. olivaceus (34.3±0.1 g) were randomly distributed into 12 tanks (425 L) in three replicate groups per treatment and fed the experimental diets for 15 weeks. At the end of the feeding trial, growth performance, survival, biological indices (condition factor, viscerosomatic index, hepatosomatic index), non-specific immune responses (lysozyme, myeloperoxidase) and intestinal histology (villi length and goblet cells) were not significantly affected by treatments. Feed utilization was significantly decreased in M10 compared to the control group. Alanine aminotransferase level was significantly higher in M10 than in the control group. Glucose level was significantly lower in B10 than in the control group. These results suggest that BSF and MW can be used as FM substitutes. However, considering feed conversion ratio and AST level, MW availability is thought to be lower than that of BSF, and feeding fish with a diet containing MW for an extended period is thought to adversely affect fish growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.23-31
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• 2024

This study evaluated the utilization of a low fish meal (LFM) diet and black soldier fly (BSF) Hermetia illucens meal and oil as a fish meal (FM) substitute or functional additive for juvenile olive flounder Paralichthys olivaceus at the Jeju fish farm. Two experimental diets replaced FM using animal (tankage, poultry byproduct and tuna byproduct meal) and plant (wheat gluten and soy protein concentrate) protein sources, containing 45% (FM45) and 35% (FM35) of FM, respectively. One experimental diet replaced FM with animal, plant, and BSF meal, fish oil using insect meal and oil (FM35+). After the feeding trial ended, no differences in growth performance, feed utilization, survival and biological indices were observed among all experimental groups. Aspartate aminotransferase and cholesterol levels in the FM35 and FM35+ groups were significantly higher than that in the FM70 group. The linoleic acid level in the muscle was significantly higher in the fish fed with the FM70 diet than in those fed with the FM45, FM35, and FM35+ diets. Thus, the LFM diet is suitable for juvenile olive flounder farming during six months.

• Clinical Nutrition Research
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• v.12 no.4
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• pp.269-282
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• 2023

Vitamin D participates in the biological function of the innate and adaptive immune system and inflammation. We aim to specify the effectiveness of the vitamin D supplementation on the side effects BioNTech, Pfizer vaccination, and immunoglobulin G response against severe acute respiratory syndrome coronavirus 2 in subjects tested positive for coronavirus disease 2019 (COVID-19). In this multi-center randomized clinical trial, 498 people tested positive for COVID-19 were divided into 2 groups, receiving vitamin D capsules or a placebo (1 capsule daily, each containing 600 IU of vitamin D) over 14-16 weeks. Anthropometric indices and biochemical parameters were measured before and after the second dose of vaccination. Fourteen to 16 weeks after supplementation, the intervention group had an immunoglobulin G (IgG) increase of 10.89 ± 1.2 g/L, while the control group had 8.89 ± 1.3 g/L, and the difference was significant between both groups (p = 0.001). After the second dose of vaccination, the supplement group significantly increased their 25-hydroxy vitamin D from initially 28.73 ± 15.6 ng/mL and increased to 46.48 ± 27.2 ng/mL, and the difference between them was significant. Those with a higher body mass index (BMI) had the most of symptoms, and the difference of side effects according to BMI level was significantly different. In 8 weeks after supplementation obese participants had the lowest IgG levels than overweight or normal subjects. The proportion of all types of side effects on the second dose was significantly diminished compared with the first dose in the intervention group. Supplementation of 600 IU of vitamin D3 can reduce post-vaccination side effects and increase IgG levels in participants who received BioNTech, Pfizer vaccine.

• Nutrition Research and Practice
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• v.18 no.5
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• pp.663-673
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• 2024

BACKGROUND/OBJECTIVES: Poly-γ-glutamic acid (γ-PGA), a natural polymer found in fermented soybean products, has been reported to play a prebiotic role in the gut. This intervention study investigated the effects of γ-PGA-containing supplement consumption on urinary microbiota in healthy adults because of limited data on such investigation. SUBJECTS/METHODS: A 4-week parallel trial including 39 male and female Korean adults, who were free of chronic diseases and infection, was designed as a randomized, double-blinded, placebo-controlled study. A total of 30 participants completed the study wherein the intervention group (n = 17) received a mixture supplement containing 600 mg/day of γ-PGA and 100 mg/day of vitamin B6, while the control group (n = 13) received a placebo. Paired datasets (baseline and endpoint data) of microbiota profiles, which were constructed via urinary assays of microbe-derived extracellular vesicles, were analyzed and compared between the two groups. RESULTS: Only the intervention group yielded significant results for the Bray-Curtis and Jaccard dissimilarity indices between baseline and endpoint data (P < 0.05). In the phylum-level analysis of microbial composition, the Firmicutes to Bacteroidetes ratio (FB ratio) tended to decrease from baseline in the intervention group; however, it increased in the control group. Differences between the baseline and endpoint FB ratios were significant between the two groups (P < 0.05). CONCLUSION: This study's findings suggest that γ-PGA-vitamin B6 supplementation potentially alters the microbial community composition of a host. Further investigation into the biological consequences of commensal microbiota alteration by γ-PGA-containing supplement consumption is warranted.

• Korean Journal of Environment and Ecology
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• v.24 no.5
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• pp.566-574
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• 2010

This study was carried out for the purpose of understanding the situation of the urban forest and presenting basic data bases for a proper management plan through the analysis of forest vegetation and soil characteristics. In three representative urban forests of Deajeon, we analyzed the differences of vegetation and soil properties in each geological location. The indices of ecological health such as Species Diversity and Maximum Species Diversity are increasing in the order of Namseon Park, Wolpyung Park and Mt. Bomun; the first is in the center of the city, the second is well-conserved inner-city park and the third is in the border of the city. In the soil analysis of Namseon Park where human disturbance is strong, the surface fuel bed was very thin just 0.5cm and the soil was harder than the other two urban forests, the soil hardness was $0.5{\sim}3.7kg/cm^2$. All three urban forests showed low $pH_{1:5}$ under 5.0 except Robinia pseudo-acasia association of Wolpyung and low exchangeable cation level. These results say that the urban forests of Deajeon have been being acidified severely and the eluviation of exchangeable cation is proceeding. The organic matter and the available phosphate level was lower than the average level of Korean forest. It means that nutrition supply is not sufficient. In Daejeon urban forests, the management plan of urban forest is necessary according to the analysis result of vegetation and soil.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.225-231
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• 2010

To understand the inhibitory activity with changing hydroxyl substituents ($R_l-R_9$) of polyhydroxy substituted 2-phenyl-l,4-benzopyrone analogues (1-25) against tyrosinase (PDB ID: oxy-form; 1WX2), molecular docking and the three dimensional quantitative structure-activity relationships (3D-QSARs: Comparative molecular field analysis (CoMFA) & Comparative molecular similarity indices analysis (CoMSIA)) were studied quantitatively. The statistically best models were CoMFA 1 and CoMSIA 1 model from the results. The optimized CoMSIA 1 model with the sensitivity of the perturbation and the prediction produced ($dq^2'/dr_{yy'}^2$=1.009 & $q^2$=0.51l) by a progressive scrambling analysis were not dependent on chance correlation. The inhibitory activities with optimized CoMSIA 1 model were dependent upon electrostatic factor (51.4%) of substrate molecules. Contour mapping the 3D-QSAR models to the active site of tyrosinase provides new insight into the interaction between tyrosinase as receptor and 2-phenyl-l,4-benzopyrone analogues as inhibitor. Therefore, the results will he able to apply to the optimization of a new potent tyrosinase inhibitors.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.171-176
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• 2008

The comparative molecular similarity indices analysis (CoMSIA) models between 3${\beta}$-Hydroxy-12-oleanen-28-oic acid (1-30) analogues as substrate molecule and their inhibitory activities ($pI_{50}$) against protein tyrosine phosphatase (PTP)-1B were derived and discussed quantitatively. Listing in order, the CoMFA>CoMSIA${\geq}$HQSAR>2D-QSAR model, these QSAR models had the better statistical values. The optimized CoMSIA F1 model at grid 3.0${\AA}$ had the best predictability and fitness ($q^2$=0.754 and $r^2$=0.976) by field fit alignment. The order of contribution ratio (%) of CoMSIA fields concerning the inhibitory activities was a H-bond acceptor (48.9%), steric field (25.8%) and hydrophobic field (25.4%), respectively. Therefore, the inhibitory activities of substrate molecules against PTP-1B were dependent upon H-bond acceptor field (A) of $R_4$-group. From the analytical results of CoMSIA contour maps, oleanolic acid derivatives will have better inhibition activities if $R_1$ group has H-bond acceptor disfavor, $R_3$group has steric disfavor and $R_4$ group has steric, hydrophobic, H-bond favor.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.63-72
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• 2009

Carbon-coated lithium iron phosphate ($LiFePO_4/C$) composites are synthesized by the modified mechanical activation method (modified MA process) and studied by the Rietveld structural refinement. Rietveld indices of $LiFePO_4/C$ indicate good fitting with $R_p=8.14%,\;R_{wp}=11.1%,\;R_{exp}=9.09%,\;R_B=3.88%$, and S (GofF, Goodness of fit) = 1.2, respectively. $LiFePO_4/C$ with a space group Pnma shows a = 10.3229(3)${\AA}$, b = 6.0052(2) ${\AA}$, c = 4.6939(1) ${\AA}$, and V = 290.98(1) ${\AA}^3$ in dimension, indicating good agreements with those of previous works. Synthetic powders are nano-sized ($65{\sim}90nm$) homogeneous particles with high purity. Thus the modified MA method will be an efficient process to get a high quality cathode material for commercial lithium batteries.