• Analytical Science and Technology
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• v.26 no.4
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• pp.287-297
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• 2013

The optimization of analytical method for the thermal desorption of seven VOCs (volatile organic compounds) by TD-GC/MS (thermal desorption-gas chromatograph-mass spectrometer) with solid phase sorbent tube, and comparative analysis for the determination of VOCs plotted by standard sorbent tubes prepared using both gas phase and liquid phase materials were investigated. The result of paired t-test showed that a liquid phase standard sorbent tube method was in agreement with a gas phase standard sorbent tube method for six species of VOCs including benzene, toluene, ethylbenzene, o-, m-, and p-xylene except for styrene at the significance level (${\alpha}=0.01$), while the 15.6% of difference in response factor between both of gas phase and liquid phase standard plotting for the determination of styrene showed that both methods were significantly different at the significance level. Therefore, the liquid phase standard plotting method was employed to reduce erroneous data for the determination of styrene including BTEX. Under the optimized analytical method by liquid phase standard sorbent tube, recovery was between $100{\pm}5%$ for 7 species of VOCs, reproducibility ranged from 0.3 to 7.7%, and method detection limit (MDL) ranged from $0.01{\mu}g/m^3$ for o-xylene to $0.27{\mu}g/m^3$ for toluene. The optimized standard method was applied to determine VOCs VOCs from indoor air of of dormitory, one bedroom apartment, and a new car.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.173-185
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• 2018

Effects of three different types of dispersions and flow improving additives composed with fatty acid esters, fatty acid metal salts and amide compound on the vulcanization and the mechanical properties properties of rubber compounds of EPDM and carbon black as fillers. were investigated using Mooney viscometer, moving die rheometer, hardness tester, and universal test machine. The aging characteristics of vulcanized EPDM compounds were also investigated. The Mooney viscosity measured at $125^{\circ}C$ showed a tendency to decrease in the order of amide type> metal salt type > ester type additive. Scorch time showed little or no difference with the addition of ester or metal salt type additives, but the amide type additive shortened a scorch time more than one minute. Rheological measurement data obtained at $160^{\circ}C$ showed that the vulcanization time was faster for metal salt type and amide type additive systems. Delta torque values of EPDM compound increased with metal salt type and amide type additives, but slightly decreased with ester type additive. The tensile strength of the EPDM compound was greatly improved when an ester type additive was added, but the amide type or metal salt type additive had no significant effect. The elongation was significantly improved for metal salt type additive, while the rest were not significantly affected. The tear strength of the EPDM compounds increased with the addition of all kinds of additives, and it increased remarkably in the case of metal salt type additive. Hardness of the EPDM compounds was nearly same value regardless of additive types. The thermal aging of the EPDM blend at $100^{\circ}C$ for 24 h showed little change in the case of metal salt type or amide type additive, but the elongation tends to decrease by 10-20% for all EPDM compounds containing additives.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.166-175
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• 2017

Objectives: Shiftwork is known to be one of the common causes of sleep and health problems and finally causes the decreased quality of life. The purpose of this study was to investigate the sleep patterns of shift-working and daytime psychiatric nurses using actigraphy and compare it with subjective assessment for sleep. Methods : Twenty-three shift-working and 25 daytime nurses were enrolled. They rated their sleep quality using Pittsburgh Sleep Quality Index(PSQI) and other self-rating scales were measured for psychosocial aspects. Actigraphy was applied to the subjects for a total of 7 days to measure the sleep parameters. They also wrote sleep diaries during the period of wearing actigraphy. Sleep-related parameters of actigraphy, global score and components of PSQI, and the results of other self-rating scales were compared between shift-working and daytime nurses. Results : Although the global score of PSQI did not show significant difference, the PSQI components showed significant differences between two groups: the shift-working nurses showed lower sleep quality, more sleep disturbance and hypnotic medication use, and worsened daytime dysfunction than daytime nurses. The shift-working nurses showed significantly shorter total time in bed and total sleep time, lower sleep efficiency, and longer average awakening time than those of daytime nurses in actigraphy. Conclusions : The results showed that shift-working nurses experienced more sleep disturbances in both subjective and objective aspects of sleep than daytime nurses. This study also suggests that actigraphy may be useful to measure the objective aspects of sleep that are difficult to assess with subjective questionnaires alone.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.60-67
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• 1999

Insecticidal activities of imidacloprid to sucking type insect pests, brown planthopper (BPH, Nilaparvata lugens) and peen peach aphid (GPA Myzus persicae), to chewing type insect pests, tobacco cut worm (TCW; Spodoptera litura) and beet armyworm (BAW, Spodoptera exigua) and to spiders, Pirata subpiraticus, Pachygnata clercki and Ummeliata insecticeps, as natural enemies were investigated by several bioassay methods. $LD_{50}$ of the chemical by topical treatment to BPH was 0.015 ${\mu}g/g$(48 hrs), while $LC_{50}s$ by leaf dipping and root zone treatment were 18.1 and 21.5 ppm, respectively. There was no difference in insecticidal activities between leaf dipping and root zone treatment. Imidacloprid also showed ovicidal effect of root zone treatment and its $LC_{50}$ was 6.8ppm $LD_{50}$ (48 hrs after treatment) of imidacloprid to GPA was $0.4{\mu}g/g$ in case of topical application and $LC_{50}s$ by leaf dipping and root zone treatment were 1.9 ppm and 13.7 ppm respectively. Leaf dipping was more effective than root zone treatment in GPA At topical application $LD_{50}$ (48 hrs after treatment) of imidacloprid to chewing type insect pests, TCW and BAW, were greater than 1,492 and $312{\mu}g/g$ and $LC_{50}s$ by leaf dipping method were 4,803 and Heater than 5,000ppm respectively. This means that imidacloprid has much less effect on chewing type insect pests, TCW and BAW. $LD_{50}$(48 hrs after treatment) of imidacloprid to wandering spiders, Pirata subpiraticus, Pachygnata clercki at topical application were greater dan $2941{\mu}g/g$ and greater than $2,976{\mu}g/g$ respectively and that to webbing spider, Ummeliata insecticeps, was 357 ${\mu}g/g$. Imidacloprid showed very low toxicity to the spiders and its selective toxicity ratios between spiders and BPH were greater than 19,600, greater than 19,800 and 23,800, respectively.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.91-96
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• 2011

Purpose: The aim of study is to expose a more uniform dose depending on the relationship between a body mass index in patients who underwent radiation therapy and an acquired dosimetric information by using a thermoluminescent dosimeter. Materials and Methods: Since 2006 to August 2011 we investigated 28 people who underwent radiation therapy were enrolled in AMC. Each patient was measured on the head, neck, chest, abdomen, pelvis, thigh, knee joint, and ankle joint using the thermoluminescent dosimeter. The measurement value of each points compared with the prescribed center point, abdominal point, and dose measurements of points on which to base the abdomen and the patient's body mass index (BMI) were compared with reference point, abdomen dose. Results: 28 patients on prescribed dose in the abdomen by which the center point, an average dose was $100.6{\pm}5.5%$, and the other seven measuring points with the average maximum difference among the head, neck, chest, pelvic, thigh, knee, and ankle were $92.8{\pm}4.2%$, $97.6{\pm}6.2%$, $96.4{\pm}5.5%$, $102.6{\pm}5.3%$, $103.4{\pm}7.9%$, $95.8{\pm}5.9%$, $96.1{\pm}5.5%$. The relationship of abdominal point dose and the patient's body mass index (BMI) was analyzed a scatter plot, and the result of linear relationship analysis by regression method, the regression of the dose (y) was -1.009 BMI (x) plus 123.3 and coefficient of determination ($R^2$) was represented 0.697. Conclusion: The total body irradiation treatment process was evaluated the dose deviation and then the prescribed dose by which the average abdominal dose was satisfied with $100.6{\pm}5.5%$. Results of the relationship analysis between BMI and dose, if we apply the correction value for each patients, it can be achieved more uniform dose delivery.

• Journal of Nutrition and Health
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• v.53 no.5
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• pp.547-561
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• 2020

Purpose: This study was conducted to segment the delivery food market and to develop customized products and services. Methods: This study analyzed 636 responses collected from customers who ordered delivery food. Statistical analyses were conducted using the SPSS program (ver. 25.0) for frequency analysis, χ²-test, one-way analysis of variance, factor analysis, and cluster analysis. Results: Four factors were extracted by exploratory factor analysis (safety-orientation, convenience-orientation, taste-orientation, and economy-orientation) to explain the consumers' food-related lifestyles. The results of cluster analysis indicated that the 'low-interest group', 'convenience and economy-oriented group', and 'gourmet and economy-oriented group' should be regarded as the target segments. Characteristic analysis of each cluster showed that lowinterest group had higher rates of married (67.1%) and living with family (85.4%) than other clusters. The convenience and the economy-oriented group had higher rates of living alone (28.9%) than others. The gourmet and the economy-oriented group had a higher percentage of unmarried (62.0%) than the others. In addition, the average age of convenience and economy-oriented group (32.3 years) and gourmet and economy-oriented group (32.5 years) were significantly lower than the safety seeker (40.0 years) (p < 0.001). Difference analysis of the consumption practice according to the cluster, revealed significant differences in the order frequency (p < 0.001), main day to order (p < 0.05), source of information about delivery food (p < 0.001), order method (p < 0.001), and co-consumer (p < 0.01). In addition, the convenience and the economy-oriented group had significantly higher overall satisfaction than the others (p < 0.001). Conclusion: These findings suggest that customer segmentation based on a food-related lifestyle can be used to build a successful marketing strategy. Therefore, restaurant managers and delivery platform operators should consider developing products and services according to the segmentation to maximize customer satisfaction.

• Journal of Nutrition and Health
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• v.50 no.2
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• pp.180-191
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• 2017

Purpose: The purpose of the study was to identify teacher's knowledge about sodium, dietary behaviors related to sodium, attitudes towards a low-salt diet, and meal attitude guidance as well as examine the relationship between these variables. Methods: The participants were 351 teachers at an elementary school in the Jeonbuk area. The data were analyzed using ANOVA, Duncan test, and Pearson correlation coefficients with SPSS v. 20.0. Results: The score for teachers' knowledge about sodium was 12.92 points of a possible 16, the score for dietary behavior related to sodium was 46.85 points of a possible 70, and the score for attitude towards a low-salt diet was 33.63 points of a possible 50. Their score for meal attitude guidance was 59.95 points of a possible 80. The knowledge showed significant differences by hypertension drug (p < 0.05) and stress level (p < 0.05). The dietary behavior of sodium use showed significant differences by gender (p < 0.01), work experience (p < 0.05), BMI (p < 0.01), drinking (p < 0.05), concern about health (p < 0.05), and stress level (p < 0.05). The attitude towards a low-salt diet showed significant differences by gender (p < 0.05), marital status (p < 0.05), work experience (p < 0.05), drinking (p < 0.05), concern about health (p < 0.001), and stress level (p < 0.05). Meal attitude guidance showed a significant difference by marital status (p < 0.001), age (p < 0.001), work experience (p < 0.001), drinking (p < 0.01), regularity of health checkup (p < 0.001), concern about health (p < 0.001), and stress level (p < 0.05). There was a low positive correlation between knowledge about sodium and dietary behavior related to sodium as well as between dietary behavior related to sodium and attitudes towards a low-salt diet. Attitudes towards a low-salt diet showed a positive correlation with meal attitude guidance. Conclusion: Therefore, it is necessary to consider educational programs on increasing knowledge and attitudes towards a low-salt diet in teachers for improvement of meal attitude guidance activities for students.

• Journal of Nutrition and Health
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• v.51 no.2
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• pp.153-167
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• 2018

Purpose: This study was conducted to identify differences in dietary behaviors, dietary life consumer education related situation competencies, and dietary lifestyles between baby-boom and echo generations by gender. Methods: Data were drawn from the 2016 Food Consumption Behavior Survey, and 2,474 subjects (baby-boom generation 1,304; echo generation 1,170) were selected. Results: The baby-boom generation more frequently ate meals at home with family than the echo generation, whereas the echo generation had meals more frequently at cafeterias, cafes, bakeries, convenience stores and with friends or colleagues than the baby-boom generation. However, no significant differences in dietary life related consumer education were observed between generations, and experience with food related consumer education and food related promotional/events was very low in general. Baby-boomers received their primary dietary information from surrounding people, whereas the echo generation received it from broadcasting. The information use competence was lower for the baby-boom generation (3.29) than echo generation (3.35), although this difference was not significant. Healthy dietary life competence did not differ significantly, whereas the baby-boom generation showed a higher level of practice competence than the echo generation. Additionally, the baby-boom generation was more likely to pursuit health and less likely to be concerned with convenience and taste quality than the echo generation. Conclusion: The frequencies of meal eating places, drinking, and eating-out differed significantly between the two generations, while the participation ratios of food related consumer education/events, attitudes toward education, and information use competence did not. Additionally, knowledge regarding healthy dietary life competencies did not differ, whereas practice level showed significant differences between generations. Among dietary lifestyles, the baby-boom generation showed higher pursuit of health and lower pursuit of convenience and taste quality than the echo generation.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1290-1302
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• 2019

This study is a descriptive research with a purpose of examining the effects of health perception, self-efficacy and social support of college students on the health promotion behaviors. The subjects of this study have targeted 196 college students, where the data collection was made from September 10, 2018 to October 5, 2018. As a result of analyzing the differences in health promoting behaviors according to general characteristics of college students, there was a statistically significant difference according to the residence type(F=8.56, p<.001), subjective health status(F=7.23, p=.001), university life satisfaction(F=8.50, p<.001), exercise status(t=6.62, p<.001), and number of breakfasts per week(F=14.13, p<.001). For the correlation between college students' health perception, self-efficacy, social support, and health promotion behaviors, health promotion behavior and health perception(r=44, p<.001), self-efficacy(r=.57, p<.001), and social support(r=.49, p<.001) has shown a significant positive correlation between them. As a result of conducting multiple regression analysis by setting general characteristics, health perception, self-efficacy and social support as independent variables in order to analyze the factors affecting health promotion behaviors of college students, The variables that have significant explanatory power on health promoting behaviors(F=34.921, p<.001) were self-efficacy, social support, number of breakfasts per week(more than 5times), whether or not to exercise, number of breakfasts per week(2 to 4times), rent and lodging for residential type, and for grade, seniors. The explanatory power of these factors on health promotion behaviors was a total of 56.9%. Conclusively, In order to Improving health promotion behavior requires the development and intervention of personalized health promotion programs for each generation that consider self-efficacy and social support and emphasize the importance of proper exercise and proper eating habits.

• Journal of Nutrition and Health
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• v.34 no.6
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• pp.637-644
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• 2001

The purpose of this study was to examine the effect of exercise and diet control program on nitrogen balance in obese children. The subjects of this study were five obese boys aged from 8 to 12 participating in the control period(C) for 3 days, exercise without energy deficit period(EEN) for one week, and exercise with energy deficit period(EED) far another one week, consecutively. The intensity of the exercise was 60-70% of HRmax and the energy was restricted at 493 kcal/day. Daily mean total energy intake was 2,152 $\pm$ 138kca1, 1,861 $\pm$ 138kca1, and 1,368 $\pm$ 87kca1 for the period C, EEN and EED, respectively. The body weight for EEN and EED decreased compared with the period C by average 1.2 $\pm$ 0.2kg and 1.8 $\pm$ 0.3kg, respectively. Of the body weight loss, the fat mass decreased bur 1.0 $\pm$ 0.3kg and 1.5 $\pm$ 0.5kg and the lean body mass by 0.2 $\pm$ 0.4kg and 0.3 $\pm$ 0.4kg, respectively. Of the daily mean nitrogen consumption was 9.1 $\pm$ 0.7g, 9.1 $\pm$ 0.8g and 7.1 $\pm$ 0.5g, the daily mean nitrogen excretion from feces was 1.3 $\pm$ 0.2g, 0.9 $\pm$ 0.1g and 0.7 $\pm$ 0.1g, and from urine was 6.7 $\pm$ 0.6g, 6.6 $\pm$ 0.5g and 6.7 $\pm$ 0.6g, for the period C, EEN and EED, respectively. Daily mean nitrogen balance excluding nitrogen excretion firm feces and urine indicated + 1.1 $\pm$ 1.0, +1.6 $\pm$ 0.6 and - 0.3 $\pm$ 0.9 for the period C, EEN and EED, respectively. Despite the negative indication during EED, there was no statistical signifiranre. The daily mean creatinine excretion was 0.5 $\pm$ 0.0g, 0.7 $\pm$ 0.1g and 0.6 $\pm$ 0.0g and the creatinine-height index(CHl) was 85.1 $\pm$ 6.7%, 83.8 $\pm$ 6.6% and 81.0 $\pm$ 6.5%, for the period C, EEN and EED, respectively, indicating little significant difference among the periods. Taking above results into consideration, it seems the exercise program conducted for this study did not substantially affect the nitrogen balance of the obese children, and may be used far the body weight control. Howeever, the adequacy of the energy restriction and amount of exercise applied to this study need to be further investigated as the nitrogen balance indicated negative and increasing tendency of the creatinine excretion showed during the EED compared with period C, despite the statistical insignificance.