• Title/Summary/Keyword: Buffering levels

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Preparation and Application of Polyurethane-urea Microcapsules Containing Phase Change Materials

  • Kwon Ji-Yun;Kim Han-Do
    • Fibers and Polymers
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    • v.7 no.1
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    • pp.12-19
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    • 2006
  • For thermal adaptable fabrics, the polyurethane-urea microcapsules containing phase-change materials (PCMs: hexadecane, octadecane and eicosane) were successfully synthesized by interfacial polycondensation using 2,4-toluene diisocyanate (TDI)/poly(ethylene glycol) (PEG400)/ethylene diamine (EDA) as shell monomers and nonionic surfactant NP-12 in an emulsion system under stirring rates of $3,000{\sim}13,000$ rpm. The mean particle size of microcapsule decreased significantly with increasing the stirring rate up to 11,000 rpm, and then leveled off. The mean particle size increased with increasing the content and molecular weight (eicosane > octadecane > hexadecane) of PCMs at the same stirring rate. The mean particle sizes of microcapsules were found to decrease with increasing the NP-12 content up to 1.5 wt%, and thereafter increased a little. It was found that the melting temperature ($T_m$) and crystallization temperature ($T_c$) of three kinds of encapsulated PCMs and their enthalpy changes (${\Delta}H_m,{\Delta}H_c$) increased with increasing PCM contents. The encapsulation efficiencies (Ee) of hexadecane microcapsule linearly increased with increasing the content of hexadecane. It was found that the stable microcapsule containing 50 wt% of hexadecane could be obtained in this study. However, Ee of octadecane and eicosane microcapsules increased with increasing PCM's contents up to 40 wt%, and then decreased a little. By considering the encapsulation efficiency, it was found that the maximum/optimum contents of octadecane and eicosane microcapsules were about 40 wt%. By the dynamic thermal performance test, it was found that the maximum buffering levels of Nylon fabrics coated with hexadecane, octadecane, and eicosane microcapsules were about $-2.4/+2.9^{\circ}C,\;-3.6/+3.6^{\circ}C\;and\;-4.0/+4.7^{\circ}C$, respectively.

Effects of Social Support on the Job Stress Symptoms and Job Performance of Workers in the Textile Industry (사회적 지원이 섬유산업 종사자의 직무스트레스 징후 및 직무성과에 미치는 영향)

  • Yoo, Hwa-Sook;Park, Kwang-Hee
    • Fashion & Textile Research Journal
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    • v.7 no.1
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    • pp.41-48
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    • 2005
  • The purpose of this study was to investigate social support buffering stress symptoms and the relationship between stress symptoms and job performance. The data were obtained from questionnaires completed by 529 workers employed in textile or clothing companies. The SPSS package was used for data analysis which included t-test, ANOVA, and correlation analysis. The results showed there were significant differences in the perceived levels of social support according to individual differences such as gender, marital status, length of service, title of current position, and division of responsibility. Workers with a high level of supervisor or co-worker social support were found to have the lower levels of stress symptoms. Social support appeared to moderate the relationship between stress symptoms and job performance.

The Moderating Effect of Spiritual Well-Being on the Relationship Between Childhood Abuse Experiences in Adults and Mental Disorders

  • Park Hannah
    • International journal of advanced smart convergence
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    • v.13 no.2
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    • pp.214-221
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    • 2024
  • This study explores the relationship between childhood abuse experiences and subsequent mental disorders in adults, with a particular focus on the moderating role of spiritual well-being. Using self-reported data from 210 graduate students in the Daejeon and Chungcheong regions, the findings demonstrate that spiritual well-being significantly moderate how childhood abuse impacts adult mental health. Specifically, individuals with lower levels of spiritual well-being experience a greater exacerbation of metnal disorders related to past abuse, while those with higher levels show a buffering effect. These results suggest that enhancing spiritual well-being could be a vital component of therapeutic interventions aimed at preventing mental disorders in adults who have experienced childhood abuse. We highlight the potential benefits of incorporating spiritual well-being into mental health strategies and call for additional research to substantiate these findings across broader populations. This unique contribution underscores the importance of considering spiritual factors int the therpeutic process, offering a new and valuable perspective in the field of mental health research.

Analysis of the Physiological Healing Effects by Forest Types - Focused on Hypertensive and Diabetic - (숲의 종류에 따른 생리적 치유효과 분석 - 고혈압과 당뇨병 환자를 중심으로 -)

  • Jeong, Na-Ra;Ahn, Deug-Soo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.5
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    • pp.1-12
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    • 2015
  • This study analyzes the physiological healing effects on users according to forest types. Forest types are classified into Chamaecyparis obtusa, Quercus serrata and Pinus densiflora and the subjects of this study, 64 hypertensives, 59 diabetics and 59 ordinary people, were tested to observe their physiological effects. The index of physiological reaction comprises electroencephalogram(EEG), heart rate variability(HRV), blood pressure and cortisol level. An analysis of the stress-buffering effect from the physiological reactions of the overall subjects indicates that Quercus serrata forests have a higher stress-buffering effect than others in terms of central nervous, endocrine and autonomic nervous systems. Chamaecyparis obtusa forests are contributory to soothing stress in the central nervous and endocrine systems. Pinus densiflora forests contribute in some indexes of the endocrine and autonomic nervous systems. In contrast, Pinus densiflora forests are less influential on a stress-buffering effect than the other two. In the level of the effect for lowering blood pressure, Chamaecyparis obtusa and Quercus serrata forests are more effective than Pinus densiflora forests. Therefore, staying in the first two forests can heighten the healing effect of the lowering of blood pressure for hypertensive patients. Every forest is efficacious to lowering diabetic blood glucose levels. Spending time in Quercus serrata forests is more effective for hypoglycemic.

Effects of Nitrogen Fertilization Levels and Some Additives on the Chemical Composition and Silage Quality of Forage Rape (Brassica napus Subsp. oleifera) II. Effects of N fertilization levels and formaldehyde treatment on the chemical composition of forage rape silage (질소시비수준과 첨가제가 사초용 유채의 사료가치 및 사일리지의 품질에 미치는 영향 II. 질소시비수준과 포름알데히드 처리가 유채 사일리지의 품질에 미치는 영향)

  • Jo, Mu-Hwan;Kim, Dong-Am;Seo, Sung
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.8 no.1
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    • pp.40-46
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    • 1988
  • This study was carried out to determine the effects of nitrogen (N) fertilization levels (0, 100 and 200kg/ha) and formaldehyde (0.4,0.8 and 1.2%: w/w CM) on the chemical composition, dry matter (DM) yield and in-vitro dry matter digestibility (IVDMD) of forage rape (Brassica napus Subsp. oleifera) silage. The results obtained are summarized as follows : 1. Forage rape was a catch crop which was highly digestible and low concentration in NDF, ADF, cellulose and lignin. 2. The concentration of the water soluble carbohydrate (WSC) and buffering capacity (PK) was 17.9% and 6.77g/100g, respectively, provided the WSC to PK ratio was 2.65. 3. DM content of silage decreased as the rate of N fertilization increased, but concentration of ammonia-N decreased. IVDMD was not affected by the rate of N fertilization. 4. By the addition of formaldehyde, the pH and IVDMD were increased, but the DM, lactic acid, total organic acid and ammonia-N content of rape silage were decreased, that was effective as a silage additive for forage rape.

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Impact of Depression, Ego-resilience, and Active Stress Coping on Internet Addiction Tendency among College Students (대학생의 우울, 자아탄력성, 적극적 스트레스 대처가 인터넷중독경향에 미치는 영향)

  • Oh, Won Oak;Shin, Hyunjeong
    • Journal of Korean Public Health Nursing
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    • v.30 no.1
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    • pp.56-69
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    • 2016
  • Purpose: The prevalence of problematic internet usage among college students is a cause for concern. There is a lack of study examining influences of cognitive protecting or buffering factors on internet addiction among college students. The purpose of this study was to examine influences of depression, ego-resilience, and active stress coping on internet addiction tendency (IAT) among college students. Methods: A cross-sectional, descriptive design was used. Data were collected between October and December 2013. A convenience sample of 244 students completed self-report questionnaires consisting of Ego-resiliency Scale, Ways of Coping Checklist, Center for Epidemiologic Studies-Depression, and Self-report Scale for Internet Use. Stepwise multiple regression analysis was performed for data analysis. Results: We found that higher levels of depression were associated with higher levels of IAT. However, an inverse association was found between active stress coping and IAT. Students who mainly used the internet for chatting showed lower levels of IAT than those who used the internet for games or blogs. These factors explained 15.1% of the variance in IAT of college students. Conclusion: The study results suggest that stress coping strategies and depression are important factors for evaluation when developing intervention programs targeting college students with problematic internet use.

The quality characteristics of Jeung-pyun made with different kinds of beans (콩의 종류에 따른 증편의 품질특성)

  • Hong, Min-Ji;Koh, Bong-Kyung
    • Korean journal of food and cookery science
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    • v.23 no.3 s.99
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    • pp.363-368
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    • 2007
  • Jeung-pyun, a very popular fermented rice cake consumed in Korea, consists mainly of rice, rice wine (Tak-Ju), and sugar. The effects of addition of different beans on the quality characteristics of the batter and Jeung-pyun were investigated. Six different beans were mixed with the rice flour at levels of 5% and 10% of the rice flour weight, respectively. The addition of Back-tae, Huk-tae, Sori-tae, which are types of soybeans, and black gram significantly increased the batter volume and viscosity. However, the fermented Back-tae (Cheongguk-jang) was not effective at increasing the batter volume and viscosity. The buffering effect of the beans was very significant on the fermented batter, and the decrease in pH of the fermented batter made with beans was less than that of the control batter without beans. Additions of the soybeans and Cheongguk-jang were most effective for the buffering effect in the fermented batter. Although the Back-tae, Huk tae, and Sori-tae were different colors and shapes, they were all soybeans and exhibited similar effects on the Jeung-pyun batter. However, the effects of the beans were not significant on the Jeung-pyun. The volume and moisture content of the Jeung-pyun made with beans were not significantly different from the volume and moisture of the Jeung-pyun made without beans. The above results suggest that the addition of different soybeans, mung beans, and black gram significantly effects on the properties of Jeung-pyun batter, but not Jeung-pyun itself.

A GIS-Based Mapping to Identify Locations at Risk for Highly Pathogenic Avian Influenza Virus Outbreak in Korea (지리정보시스템 기반의 고병원성 조류인플루엔자 발생 위험지도 구축)

  • Lee, Gyoungju;Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.34 no.2
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    • pp.146-151
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    • 2017
  • Six major outbreaks of highly pathogenic avian influenza (HPAI) occurred from 2003 to 2016 in Korea. Epidemiological investigations of each outbreak revealed that migratory birds were the primary source of the HPAI virus. During the last five years, the geographic transmission pattern of domestic HPAI seems to have extended from local to nationwide; therefore, it is necessary to identify specific locations in which poultry farms are at elevated risk for HPAI outbreak to enable targeted surveillance and other mitigation strategies. Here, a geographical information system (GIS)-based analysis was used to identify geographic areas at high risk for future HPAI incidents in Korea based on historical outbreak data collected between December 2003 and April 2016. To accomplish this, seven criteria were used to identify areas at high-risk for HPAI occurrence. The first three criteria were based on defined spatial criteria buffering of 200 bird migration sites to some defined extents and the historical incidence of HPAI outbreaks at the buffering sites. The remaining criteria were based on combined attribute information such as number of birds or farms at district levels. Based on the criteria established for this study, the most-likely areas at higher risk for HPAI outbreak were located in Chungcheong, Jeolla, Gyeonggi, and Gyeongnam provinces, which are densely populated poultry regions considered major poultry-production areas that are located along bird migration sites. The proportion of areas at risk for HPAI occurrence ranged from 4.5% to 64.9%. For the worst criteria, all nine provinces, including Jeju Island, were found to be at risk of HPAI. The results of this study indicate that the number of poultry farms at risk for HPAI outbreaks is largely underestimated by current regulatory risk assessment procedures conducted for biosecurity authorization. The HPAI risk map generated in this study will enable easy use of information by policy makers to identify surveillance zones and employ targeted surveillance to reduce the impact of HPAI transmission.

Moderating effects of leader-member exchange (LMX) on job burnout in dietitians and chefs of institutional foodservice

  • Lee, Kyung-Eun
    • Nutrition Research and Practice
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    • v.5 no.1
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    • pp.80-87
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    • 2011
  • The objectives of the study were to investigate job burnout and leader-member exchange (LMX) levels as well as to evaluate buffering effects of LMX on burnout among dietitians and chefs at institutional foodservices. Hypotheses were proposed based on the Job Demands-Resources model and LMX theory. The study population consisted of dietitians and chefs who were in charge of managing unit operations in a nationwide contract management company. Positive/negative affectivity, workload, job burnout, and LMX scales that bad been validated in previous research were adopted A total of 552 questionnaires were distributed and 154 responses were returned. Results indicated that respondents' burnout levels were moderate and emotional exhaustion was greater than cynicism. In terms of LMX, the surveyed dietitians and chefs showed higher respect toward their supervisors than loyalty. When positive affectivity and negative affectivity were controlled, workload influenced emotional exhaustion and professional efficacy significantly. With affectivity and workload controlled, however, LMX did not influence any dimensions of burnout. The moderating effect of LMX on the relationship between workload and cynicism was significant. That is, the effect of workload on cynicism was weak if the dietitians and chefs perceived the relationship with their supervisor positively. Based on the findings and literature reviewed, how to mitigate job burnout among foodservice managers is discussed.

Effects of Dietary Buffering Characteristics and Protected or Unprotected Acids on Piglet Growth, Digestibility and Characteristics of Gut Content

  • Bosi, P.;Jung, H.J.;Han, In K.;Perini, S.;Cacciavillani, J.A.;Casini, L.;Creston, D.;Gremokolini, C.;Mattuzzi, S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.12 no.7
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    • pp.1104-1110
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    • 1999
  • We condicted two experiments to evaluate the interaction among fumaric acid (FA), protected acids (PA), or no additional acid (NO) and two different levels of acid buffering capacity (BC) in diets for 14-d-old weaned pigs. BC was varied substituting mono-calcium phosphate and calcium sulfate for dicalcium phosphate and calcium carbonate. In the high BC diet plus PA, FA was also added. In Exp. 1, 48 gilts were raised for 31 days on the six diets, evaluating growth performance and fecal digestibility. In Exp. 2, 42 gilts were raised. With each diet three subjects were sacrificed after 19 days and four after 38 days. In addition, six subjects were sacrificed at weaning. Growth and carcass performance, ileal digestibility, bacterial populations and pH in the gut were assessed. The piglet performance and stomach, ileal and cecal pH, and empty body composition were not affected by the diets. Empty body composition other than ash content was affected by piglet age (p<0.01). The BC did not influence digestibility. The dietary inclusion of PA improved fecal digestibility of protein (p<0.05) compared to the addition of FA and NO. Ileal digestibility slightly increased with both acid additions (p<0.10), the groups receiving PA showing the higher values. Piglets fed diets with low BC had lower Lactobacillus and E. coli counts in the ileum (p=0.07) and higher Lactobacillus in the colon (p=0.08). Acidified diets tended to reduce E. coli counts in the ileum (p=0.10) and increased Lactobacillus in the colon (p=0.09). The addition in the diet of PA increased Lactobacillus in the ileum compared to the sole addition of free fumaric acid (p=0.07). The addition of protected acids, combined with free fumaric acid in the case of high BC diets, increased protein digestibility and Lactobacillus counts and reduced E.coli counts. Only some changes in the concentration of bacterial population can be expected with a diet of low BC.