• Animal Bioscience
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• v.36 no.2
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• pp.248-255
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• 2023

Objective: Stress factors such as high temperatures, overcrowding, and diurnal temperature range exert profound negative effects on weight gain and productivity of broiler chickens. The potential of gamma aminobutyric acid (GABA) as an excitatory neurotransmitter was evaluated under various stress conditions in this study. Methods: The experiment was conducted under four different environmental conditions: normal, high temperature, overcrowded, and in an overcrowded-diurnal temperature range. The experimental groups were divided into (-) control group without stress, (+) control group with stress, and G50 group (GABA 50 mg/kg) with stress. Weight gain, feed intake, and feed conversion ratio were measured, and stress reduction was evaluated through hematologic analysis. Results: The effects of GABA on broilers in four experimental treatments were evaluated. GABA treated responded to environmental stress and improved productivity in all the experimental treatments. The magnitude of stress observed was highest at high temperature, followed by the overcrowded environment, and was least for the overcrowded-diurnal temperature range. Conclusion: Various stress factors in livestock rearing environment can reduce productivity and increase disease incidence and mortality rate. To address these challenges, GABA, an inhibitory neurotransmitter, was shown to reduce stress caused due to various environmental conditions and improve productivity.

• 대한공업교육학회지
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• v.35 no.2
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• pp.224-237
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• 2010

When the underwater structure sails high speed, noise and vibration propagate to the sensor in the nose of the dome. In this paper, to avoid this kind of noise and vibration CRP(Carbon Reinforced Plastic) material and SNORE ring(Self-NOise REduction Ring) are attached at the curved structure and simulates its isolation characteristics using commercial software. Vibration displacement and stress are calculated at the planar sensor array. The material of the curved structure is aluminum and maximum outer diameter is 53Omm, 215mm in length, 270mm in planar diameter, respectively. Based on the simulation results, reduction ratio of the received normal stress at the sensor is above 95% at the frequency of 12kHz and 15kHz. At the mid point of the planar sensor the normal stress is higher than 20mm and 40mm apart. This results can be used to increase the sensitivity of the acoustic sensor as a basic data.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.79-83
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• 2008

The present study describes glutamate which is known as excitatory neurotransmitter is related with oxidative damages and the Viola mandshurica extracts. Showed protective effects against glutamate-induced cytotoxicity. The protective effect of antioxidant on the glutamate treated N18-RE-I05 cells was determined by a MTT reduction assay. The neuroprotective effect of methanol, ethanol, and acetone extracts from V. mandshurica against glutamate-induced cytotoxicity was assessed by the results of an MTT reduction assay. Among the three extracts, the acetone extract showed the highest protective effect by the results of an lactate dehydrogenase release assay. Therefore, these results suggest that V. mandshurica extracts could be a new potential candidate against glutamate-induced oxidative stress.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.95-104
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• 2005

Statement of problem. Higher stresses at the cervical bone around dental implants have been seen as a primary cause of the bone resorption at the site. Purpose : To determine the possibility of stress reduction by assembly of different abutment and implant in diameters. Material and methods. Abutments of several different diameters assembled on the top of XiVE$^{(R)}$ implants were axisymmetrically modeled for a series of finite element analyses. Abutments of 3.4, 3.8, 4.5, and 5.5 mm diameters were assumed to be sit on implants of the same or bigger diameters. All the abutments with an exception of 3.4mm dia, are technically possible to be assembled on bigger implants. Main consideration was given to the stresses at the cervical cortical bone induced by loads of parallel to the implant axis. Results and conclusions. 1. Higher stresses were observed at the cervical area of all the models of the same diameters of abutment and future. The peak stresses, which were shown to be a function of the fixture diameter, were from 1-1.85MPa. 2. Difference in the diameters of the abutments and the implants actually reduced the cervical bone stresses. 3. Downsizing of the abutment by one step resulted in 0.1MPa (5%) reduction of the stresses. In light of the relatively lower bone stress, however, this amount of stress reduction was decided to be biomechanically insignificant.

• 월간산업보건
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• s.111
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• pp.42-43
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• 1997

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.1
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• pp.32-40
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• 2008

According to the statistic of industrial disaster in 2006 presented by the Ministry of Labor, there were 10,235 people with occupational diseases adding 2,740 more people (36.6%) compared to the previous year. Concerning the occupational diseases, 1,607 people had brain-cardiovascular diseases comprising more than 15% of all occupational diseases, and excessive workload and occupational stress seemed to play important parts. According to Korean Society of Occupational Stress, among 7,000 workers at 254 businesses in Korea, 73% of them were reported to be exposed to potential occupational stress and 22% of them were reported to be under severe stress. The increase of occupational stress among workers comes from excessive competition caused by business restructuring, promotion competition, annual salary system and so forth. Occupational stress threatens the heath and even the life of workers and lowers business competitiveness. Using the Korean occupational stress reduction model to the workers at small and medium businesses in Incheon area, therefore, the project intends to measure the level of stress among office workers and examine its relatedness to the VTD subjective symptoms. In addition, the project intends to present some methods to reduce occupational stress and increase business efficiency at work by studying and analyzing the various elements that workers use to reduce their occupational stress.

• Korean Journal of Adult Nursing
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• v.21 no.6
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• pp.639-651
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• 2009

Purpose: This study examined relationships among stress, stress coping strategies, and somatization in mothers-in-law from multi-cultural families in a rural area. Methods: Elderly mothers-in-law (n=227) living with foreign daughters-in-law completed a self-reporting questionnaire. Data were collected from April to August 2009. Questions related to stress (Visual Analog Scale, VAS), coping strategies (Coping Strategy Scale) for stress, and somatization (Symptom Check List 90, Revised). SPSS/WIN 12.0 program was used for descriptive analysis, t-test, one-way ANOVA, Pearson correlation, and multiple regression analyses. Results: Subjects had a moderate level of stress (5.03). There were significant differences in stress level according to age, educational level, religion, chronic disease, health status, number of children, agreement of an international marriage of her sons, satisfaction in living with a foreign daughter-in-law, and family conflict. Stress showed a significant positive correlation with offensive coping strategy, passive strategy, and somatization. Stress, offensive coping strategy, and passive coping strategy affected the level of somatization. Conclusion: In a family situation involving co-habitation of mother- and foreign daughter-in-law, increased stress experienced by the mother-in-law can lead to increased offensive and passive coping strategies, and increased somatization. More effective means of stress reduction are needed for mothers-in-law from multi-cultural families.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.263-266
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• 1997

Three dimensional numerical model based on the finite element method(FEM) were developed to predict the mechanical behavior of hip implants. The purpose of this study is to investigate the stress distribution of two types of cementless total hip replacement femoral component -a straight stem and a curved stem, and to compare their effect on the stress shielding between two types by three dimensional finite element method. The authors analyzed von Mises stress in the cortex & stem and compared the stress between the straight and the curved stem. In comparison of stresses between two different design of femoral stem, there was 25% more decrease of stress in straight stem than curved stem in the medial cortex at proximal region. The straight stem had consistently much lower stresses than the curved stem throughout the whole medial cortex with maximum 70% reduction of stress. However, there was little change in stress between nature and 2 implanted femur throughout the lateral cortex. Stress of femoral stem was much higher in the straight stem than the curved stem up to 60%. The straight stem had more chance of stress shielding and a risk of fatigue fracture of the stem compared with the curved stem in noncement hip arthroplasty. In design of femoral stem still we have to consider to develop design to distribute more even stress on the proximal medial cortex.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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• pp.58-68
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• 1998

Advantages of adhesively bonded joints and techniques of weight reduction have led to increasing use of structural adhesives such as LSI(large scale integration) package, automobile, aircraft in the various industries. In spite of such wide applications of adhesively bonded joints, the evaluation method of bonding strength has not been established. Stress singularity occurs at the interface edges of adhesively bonded joints and it is required to analyze it. In this paper, the stress singularity using 2-dimensional elastic boundary element method (BEM) with the changes of the lap length and adhesive for single lap joint was analyzed, and experiments of strength evaluation were carried out. As the results, the evaluating method of bonding strength considering stress singularity at interface edges of adhesively bonded joints and stress intensity factor of interface crack have been proposed in static and fatigue test.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.190-195
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• 2013

In this study, the response of 22 soybean cultivar sprouts to flooding stress was investigated. After sprouts were subjected to flooding stress for 10 days at the V4-V5 growth stages, their dry weights were compared. All plants were kept in a greenhouse under natural light conditions, an average daytime temperature of $35.6{\pm}5.3^{\circ}C$ and an average nighttime temperature of $18.2{\pm}1.7^{\circ}C$. Soybeans were grown in a concrete bed filled with silt loam soil. Subjecting plants to flooding stress resulted in a large reduction in plant dry weight, plant height, number of nodes, and number of leaves. Cultivars differed significantly in their responses to flooding stress, as indicated by these characteristics (p<0.05). Soybean cultivars were classified into three groups based on their degree of flood tolerance: strong, moderate, and weak. Hannamkong, Namhaekong, Sobaegnamulkong, and Sorogkong had strong tolerance for flood conditions. Tawonkong, Pureunkong, Eunhakong, Myeongjunamulkong, Doremikong, Saebyeolkong, Paldokong, Sowonkong, Pungsannamulkong, Dagikong, Dachaekong, and Anpyeongkong had weak tolerance for flood conditions.