• Journal of Wetlands Research
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• v.25 no.4
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• pp.306-314
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• 2023

Stream sediments are an important component of water quality management because they are receptors of various pollutants such as heavy metals and organic matters emitted from upland sources and can be secondary pollution sources, adversely affecting water environment. To effectively manage the stream sediments, identification of primary sources of sediment contamination and source-associated control strategies will be required. We evaluated the performance of machine learning models in identifying primary sources of sediment contamination based on the physico-chemical properties of stream sediments. A total of 356 stream sediment data sets of 18 quality parameters including 10 heavy metal species(Cd, Cu, Pb, Ni, As, Zn, Cr, Hg, Li, and Al), 3 soil parameters(clay, silt, and sand fractions), and 5 water quality parameters(water content, loss on ignition, total organic carbon, total nitrogen, and total phosphorous) were collected near abandoned metal mines and industrial complexes across the four major river basins in Korea. Two machine learning algorithms, linear discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the sediments into four cases of different combinations of the sampling period and locations (i.e., mine in dry season, mine in wet season, industrial complex in dry season, and　industrial complex in wet season). Both models showed good performance in the classification, with SVM outperformed LDA; the accuracy values of LDA and SVM were 79.5% and 88.1%, respectively. An SVM ensemble model was used for multi-label classification of the multiple contamination sources inlcuding landuses in the upland areas within 1 km radius from the sampling sites. The results showed that the multi-label classifier was comparable performance with sinlgle-label SVM in classifying mines and industrial complexes, but was less accurate in classifying dominant land uses (50~60%). The poor performance of the multi-label SVM is likely due to the overfitting caused by small data sets compared to the complexity of the model. A larger data set might increase the performance of the machine learning models in identifying contamination sources.

• Korean Journal of Psychosomatic Medicine
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• v.31 no.2
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• pp.63-71
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• 2023

Urinary incontinence (UI), affecting 3%-11% of males and 25%-45% of females globally, is expected to rise with an aging population. It significantly impacts mental health, causing depression, stress, and reduced quality of life. UI can exacerbate psychiatric conditions, affecting treatment compliance and effectiveness. It is categorized into transient and chronic types. Transient UI, often reversible, is caused by factors summarized in the acronym DIAPPERS: Delirium, Infection, Atrophic urethritis/vaginitis, Psychological disorders, Pharmaceuticals, Excess urine output, Restricted mobility, Stool impaction. Chronic UI includes stress, urge, mixed, overflow, functional, and persistent incontinence. Drug-induced UI, a transient form, is frequently seen in psychiatric treatment. Antipsychotics, antidepressants, and other psychiatric medications can cause UI through various mechanisms like affecting bladder muscle tone, altering nerve reflexes, and inducing other conditions like diabetes or epilepsy. Specific drugs like lithium and valproic acid have also been linked to UI, though mechanisms are not always clear. Managing UI in psychiatric patients requires careful monitoring of urinary symptoms and judicious medication management. If a drug is identified as the cause, options include discontinuing, reducing, or adjusting the dosage. In cases where medication continuation is necessary, additional treatments like desmopressin, oxybutynin, trihexyphenidyl, or amitriptyline may be considered.

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.143-159
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• 2023

The study aimed to evaluate the antioxidative effects of rosemary (Rosmarinus officinalis L.) and clove (Syzgyium aromaticum L.) essential oils on fried Korean native thigh meat, including their impact on processed characteristics and flavor compounds. Clove essential oil showed higher DPPH scavenging activity, FRAP and total phenol content compared to rosemary essential oil (P<0.05). The treatments with the addition of 0.005% and 0.01% rosemary (0.005RB and 0.01RB) and clove (0.005CB and 0.01CB) essential oils to the batter weight compared to control that did not include essential oils in batter. The addition of rosemary and clove essential oils to fried Korean native chicken thigh meat did not significant affect proximate composition, pH, TBARS, sensory characteristics. Except for 0.005CB, treatments adding essential oils decreased cooking loss (P<0.05) and 0.005CB showed significantly higher pick-up value than control. Addition of clove essential oil in fried Korean native chicken thigh meat resulted in higher levels of arachidonic acid compared to control (P<0.05). Volatile organic compounds (VOCs) analysis showed that addition of rosemary essential oil might mask its own VOCs, while clove essential oil addition reduced some pyrazine compounds. Although addition of rosemary and clove essential oil did not have significant sensory characteristics on fried Korean native chicken thigh meat, instrumental analysis revealed changes in the compounds that influenced flavor. Further studies are required to evaluate the stability of flavor and sensory characteristics of fried Korean native chicken thigh meat with added essential oils during storage.

• Journal of Nutrition and Health
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• v.56 no.6
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• pp.683-701
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• 2023

Purpose: The purpose of the study was to analyze the status of dietary behavior and nutrition intakes according to the gender and the level of physical activity of adolescents. Methods: Data from 659 adolescents aged 13 to 18 years who participated in the Korea National Health and Nutrition Examination Survey (2017-2018) were analyzed. Collected data were analyzed using complex sampling data analysis with SPSS v. 27.0. Results: The adolescents were categorized into three groups based on their physical activity as follows: The first group with high physical activity (8.9%), a second group with normal physical activity (29.7%), and a third group without physical activity (61.4%). Boys showed significantly higher physical activity than the girls. Adolescents with high physical activity had a significantly lower body mass index than adolescents without physical activity, but their meal regularity, subjective health status, and recognition of body image were significantly higher. In terms of biochemical factors, adolescents with high physical activity had lower triglycerides and cholesterol than adolescents without physical activity, while hemoglobin and hematocrit were significantly higher. In addition, the intakes of energy, carbohydrates, proteins, fat, vitamin B₁, niacin, calcium, phosphorus, sodium, potassium, iron increased significantly as adolescents' physical activity increased. Conclusion: The physical activity of adolescents had a positive effect on dietary behavior, lifestyle, and nutritional factors. Therefore, it is necessary to increase participation in physical classes in schools and develop various programs considering the level of physical activity among adolescents.

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.528-536
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• 2023

In Korea, from January 2023, the Act on Labeling and Advertising of Food was revised to reflect the use-by-date rather than the sell-by-date. Hence, the purpose of this study was to establish a system for calculating the safety factor and determining the recommended use-by-date for each food type, thereby providing a scientific basis for the recommended use-by-date labels. A safety factor calculation technique based on scientific principles was designed through literature review and simulation, and opinions were collected by conducting surveys and discussions including industry and academia, among others. The main considerations in this study were pH, Aw, sterilization, preservatives, packaging for storage improvement, storage temperature, and other external factors. A safety factor of 0.97 was exceptionally applied for frozen products and 1.0 for sterilized products. In addition, a between-sample error value of 0.08 was applied to factors related to product and experimental design. This study suggests that clearly providing a safe use-by-date will help reduce food waste and contribute to carbon neutrality.

• Food Science and Preservation
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• v.30 no.1
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• pp.88-97
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• 2023

As livestock consumption in Korea has been gradually increasing, the quality of the final products has been improved to meet this increased demand. In particular, maintaining the water holding capacity (WHC) and minimizing the drip loss during the thawing of frozen meat are of utmost importance. This study investigated the physicochemical properties of frozen pork subjected to thawing under different conditions: at room temperature (20℃, under air), at a low temperature (4℃ refrigerator, under air), under water (20℃, under water in a vacuum bag), under microwave (microwave-thawing, 260 W), and under low-pressure tumbling (20℃, 0.015 bar, tumbling). The shortest thawing time for frozen pork was recorded upon low-pressure tumbling thus indicating a fast heat transfer. The lowest drip loss (0.2%) and highest WHC (94.5%) were also recorded under this condition. A significantly higher drip loss was observed upon microwave- (1.0%) and water-thawing (1.2%), which resulted in the lowest WHC in microwave thawing (87.2%). The highest total count of aerobic bacteria and coliform group were observed upon room temp thawing while the low pressure tumbling and thawing resulted in the lowest aerobic bacteria (1.90 log CFU/g) and coliform (0.78 log CFU/g) count. Consequently, thawing by low pressure tumbling afforded the best food quality.

• Korean Journal of Poultry Science
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• v.51 no.1
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• pp.11-19
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• 2024

This study was conducted to evaluate the potential of using laying hens as meat type chickens. Male broiler (Ross 308, R3), laying hens (Hy-Line Brown, HL), and Korean native chickens (Hanhyup-3, H3) were used, and 100 heads of each were prepared. Carcass characteristics, meat quality, and sensory quality characteristics were compared as analysis items. The rearing environment and feed for all treatments were identical to the broiler rearing manual, and the lighting system was maintained at 23L:1D. Feed and water were provided ad libitum. The test ended when the average weight of each treatment group reached 1.5 kg, and individuals of similar weight were randomly selected and compared. As a result of this study, the live weight of the selected individuals was approximately 1.5 kg, which was similar for all treatments (P>0.05). However, carcass weight and ratio and breast meat production were highest in R3, while HL had higher ratios of legs, wings, and neck (P<0.05). The H3 group showed high pH and WHC levels and low cooking loss, and R3 improved chicken meat color (P<0.05). In particular, the fat content in meat was lowest in HL (P<0.01). Nucleic acid substances ATP, Hx, ADP, AMP, and INO were abundant in R3, and IMP content was highest in HL (P<0.05). In sensory evaluation, all treatments showed similar characteristics and overall preferences (P>0.05). Based on the findings, it appears that HL, a male laying hen, produces meat with unique characteristics such as low fat content and high IMP content.

• Korean Journal of Poultry Science
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• v.40 no.2
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• pp.121-127
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• 2013

This work was carried to evaluate production efficiency factor, carcass yield and meat quality with weeks of Large-type Korean native ducks. Korean native ducks (n = 90) from National Institute of Animal Science (RDA, Korea) were used in this work. Ninety ducks were divided into 6 groups (15 birds/group) and were fed with meat-type duck diets for 8 wk old. When ducks grew at specific wk (6, 7 and 8 weeks), 2 ducks per group were slaughtered at 6, 7 and 8 wk old. Production efficiency factor, carcass yield, partial meat and meat quality were researched in this work. There was no significant difference on livability with weeks, but body weight at 7 and 8 wk old was higher than that at 6 wk old (P<0.05). Feed conversion ratio at 6, 7 and 8 wk old were 2.25, 2.69 and 3.21, respectively, so there was significant difference with weeks (P<0.05). Production efficiency factor at 6, 7 and 8 wk old were 256.6, 199.8 and 153.0, respectively, so there was significant difference with weeks (P<0.05). Carcass yield at 8 wk old was higher than that at 6 and 7 wk old as 73.5% (P<0.05). Lightness at 6, 7 and 8 wk were 41.8, 39.0 and 38.1, respectively, and that at 6 wk old was the higher than other weeks (P<0.05). There was no significant difference on redness at 6, 7, and 8 wk old (P>0.05) and yellowness at 8 wk old was higher compared to other weeks (P<0.05). Cooking loss was the highest at 6 wk old as 31.6%, but water holding capacity was the highest at 8 wk old (P<0.05). There was no significant difference on shear force among weeks. pH at 6 wk old was the lower than that of other weeks as 5.84. Moisture content significantly decreased with weeks (P<0.05) and fat content at 8 wk was the highest as 1.88% (P<0.05). Protein content significantly increased with weeks until 20.9% at the age of 8 wk (P<0.05). Ash content at 7 and 8 wk old was the higher than that at 6 wk old (P<0.05). There was no significant difference on juiciness, tenderness, and flavor with weeks. Finally, these results may provide that shipping time at 7 wk old preferred to that at 6 and 7 wk old, but further research was needed because of deficiency of data.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.67-75
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• 1974

The studies are to know how much cocoon crops is damaged by the stained leaf with nicotine produced from the tobacco field cultivated in mulching system in spring season and by residual nicotine in autumn season. Furthermore, the new knowledges are to make both industries keep up with their development. In spring season mulberry Held is located higher on the West-North of tobacco held below 20 degrees of slope and with 36 per cent of East-South wind and 18 per cent of South wind blowing from tobacco fold to the mulberry fold. In addition, silkworm larvae are fed with the mulberry leaf produced in the different plots placing by the different distances, l0m, 25m, 50m, 80m, and loom far from the tobacco Held as a control and it is also considered that narcotic larvae including the dead larvae are not observed. On the other hand, it is noted that better leaf quality and abundant growth of mulberry tree is produced from the mulberry fold closer to the tobacco field and with a low slope. 1) Maximum weight of larval body at the 5th stage is damaged by the stained leaf with the nicotine up to 25m far from the tobacco held. 2) The larvae fed with the mulberry leaf in mulberry Held up to 25m far from the tobacco fold produce small number of the fresh cocoons per 1 liter. 3) Low single cocoon weight and low cocoon shell weight are produced by the poison damaged larvae fed with the mulberry. leaf up to 25m far from the tobacco field and weight of cocoon shell is damaged higher than the single cocoon weight. It is resulted in low percentage of cocoon shell. 4) Cocoon yield including the double cocoon from 10,000 larvae is decreased by the larvae fed with the stained leaf in the mulberry fold up to 25m far from the tobacco fold and 19 per cent of cocoon yield is decreased with 2.4kg of cocoon yield in l0m plot and with 2.5kg of cocoon yield in 25m plot at the first season and at the 2nd season with 1.8kg o( cocoon yield in l0m plot and with 11.5kg of cocoon yield in 25m plot, 11 per cent and 9 per cent of cocoon yield including double cocoon from 10,000 larvae is decreased, as compared with the control, respectively. With these results, it is observed that nicotine damage is occurred to the silkworm larvae if the larvae are fed with the leaf in the mulberry Held within 25m-50m far from the tobacco field.

• Explosives and Blasting
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• v.9 no.1
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• pp.3-13
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• 1991

The cautious blasting works had been used with emulsion explosion electric M/S delay caps. Drill depth was from 3m to 6m with Crawler Drill ${\phi}70mm$ on the calcalious sand stone (soft -modelate -semi hard Rock). The total numbers of test blast were 88. Scale distance were induced 15.52-60.32. It was applied to propagation Law in blasting vibration as follows. Propagtion Law in Blasting Vibration $V=K(\frac{D}{W^b})^n$ were V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W : Maximum charge per delay-period of eight milliseconds or more (kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents where the quantity $\frac{D}{W^b}$ is known as the scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagorized in three groups. Cubic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge Per delay Plots of peak particle velocity versus distoance were made on log-log coordinates. The data are grouped by test and P.P.V. The linear grouping of the data permits their representation by an equation of the form ; $V=K(\frac{D}{W^{\frac{1}{3}})^{-n}$ The value of K(41 or 124) and n(1.41 or 1.66) were determined for each set of data by the method of least squores. Statistical tests showed that a common slope, n, could be used for all data of a given components. Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom over loom distance because the frequency is verified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m ------- under l00m ${\cdots\cdots\cdots}{\;}41(D/sqrt[2]{W})^{-1.41}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}A$ Over 100m ${\cdots\cdots\cdots\cdots\cdots}{\;}121(D/sqrt[3]{W})^{-1.66}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}B$ where ; V is peak particle velocity In cm / sec D is distance in m and W, maximLlm charge weight per day in kg K value on the above equation has to be more specified for further understaring about the effect of explosives, Rock strength. And Drilling pattern on the vibration levels, it is necessary to carry out more tests.