• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.95-105
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• 1986

For the purpose of obtaining a basic data in selecting a suitable material with clinical care, this study was designed to measure the shear stress and to examine the fracture pattern of various dentin bonding restorative materials using 43 extracted bicuspids. The following results were obtained. 1. In dentin, Silux/Scotchbond group showed the highest value ($34.5{\pm}14.7kg/cm^2$) and Fuji Ionomer Type II group and Heliosit/Dentin-Adhesit group showed almost same bond strength in the next place. Durafill/Dentin-Adhesive group showed an infinitesimal value. ($3.1{\pm}1.4kg/cm^2$) 2. Every group showed no difference in bond strength between upper and lower teeth. Between buccal and lingual surfaces. Fuji Ionomer Type II and Durafill/Dentin-Adhesive groups showed too. But, in Silux/Scotchbond and Heliosit/Dentin-Adhesit groups, it was shown that the bond strength in lingual was stronger than in buccal. 3. There was resin fracture with cohesive fracture of bonding agent in Enamel group. In dentin, adhesive-cohesive fracture and adhesive fracture were shown. 4. The stronger bond strength was, the more frequently cohesive fracture occurred. Dentin-Adhesit group showed specific shining appearance as if varnish became hard.

• Laser Solutions
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• v.11 no.2
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• pp.8-14
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• 2008

Sintered specimen which used for a blade of diamond tool was manufactured in order to verify $CO_2$ laser weldability depend on sintered temperature. Five kind of specimen were prepared and the range of temperature is from $600^{\circ}C$ to $1000^{\circ}C$ at intervals of $100^{\circ}C$. As a result of the sintered density test, the porosity rate appeared in the range of $2.1%{\sim}21.4%$. After welding, the most segments had exceeds the minimum fracture stress (600MPa, The Standard Safety of Europe) at the welding strength test except on the sintered at $600^{\circ}C$. In case of the sintered at $700^{\circ}C$, even satisfied the safety allowable stress but cannot get the good quality for bead appearance because of humping defect. In the conclusion, we could know that it showed not only relatively soundness bead but also enough welding strength when the sintered blade of diamond tool is included less than 4% of porosity rate.

• Textile Coloration and Finishing
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• v.34 no.2
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• pp.127-133
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• 2022

With the increasing interest in the expression of individuality and appearance of modern people, it is time to conduct research and development of novel hair coloring from various angles. Therefore, taking into account the order of discoloration of hair pigments, we selected a creative and novel emulsion as a novel material for hair coloring, rather than a cosmetic material such as hot water extract using natural products dealt with in previous studies, commercially available hair manicure, and oxidation hair dye for hair. Thus, the change in tensile strength and elongation of hair samples by color was studied. As a result of the study, hair with green emulsion paint had a significantly higher maximum load, maximum stress, maximum elongation and breaking load, breaking stress, breaking elongation values are shown. Maximum in terms of modulus, green emulsion applied hair and the control group were higher in the 0-15s strain and 15-145s sections, respectively, and the tangential modulus value was much higher in the control group than the experimental group hairs in all the 0-145s sections. This study, which analyzes the dynamic changes of hair samples that extend the daily color gamut, will greatly contribute to the development of innovative hair coloring materials in the research and production of hair beauty works, and it is judged that it will also contribute to the development of the beauty industry.

• Journal of Oral Medicine and Pain
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• v.32 no.1
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• pp.57-67
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• 2007

In currently, stress diseases are increased that present several sign and symptoms. Under stress condition, there are dry mouth, burning mouth syndrome, oral mucosa diseases and halitosis more frequently. Changing of salivary proportion is checked in almost patients with changing of function and structure in salivary gland. This study purpose are what effect stress does on salivary gland, and a-amylase on salivary gland. This study was resulted that 1. Under restraint stress, acinar cells are vacuolization and changing of intercellular spaces are separated, and peripheral tissues of duct are changed 2. Acinar cells were shrunk after 3 hours under restraint stress, intercellular space was separated after 6hours, peripheral tissues of duct started to change after 72 hours, and acinar cells and peripheral tissues of duct were all severely changed after 168hours. 3. In immunohistochemical study, amylase reaction was showed partially and irregularly after 3 hours, was getting little milder after 6 hours. And amylase reaction was gradually increased from the time of 12 hours after experiment up to the time of 48 hours after experiment. But after 168 hours, amylase appearance was diminished. According this result, emotional stress can change of salivary gland structure, and amylase secretion, the important digestive enzyme from salivary gland is changed and it is supposed to make digestive disorder and to make halitosis efficiency. So, we need to study about secretion of amylase.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.369-374
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• 2009

The purpose of this study was to survey Korean soldiers' oral healthcare practice and attitudes along with their stress level, and thereby to identify possible correlations among those factors. The survey was conducted from June 11 to Oct. 10, 2008 in G-gun, Chungbuk. province for soldiers. The questionnaire was consisted of the oral healthcare practice and attitude, stress level. As a result, it was found that our respondents scored 3.55 out of possible 9 point in their stress level, which indicated that they had relatively low stress on the whole. According to survey on their oral healthcare practice and attitude depending on their general characteristics, it was found that the higher academic career was associated directly with the more practices of oral healthcare, and nonsmoking group showed more practices of oral healthcare than smoking group. It was found that 'schoolwork and workplace' and 'sexual problem' were critical stress factors on our respondents' oral healthcare attitudes. And it was also found that 'outward appearance complex', 'personality complex', 'conflicts with parents' and 'sexual problem' were critical stress factors on their oral healthcare practices. Since our soldiers' maintenance of their oral healthcare is beneficial to both individual and national aspects, it is necessary for interested parties including dental surgeons to make efforts to develop a promotional program for military dental healthcare project and provide a series of reorientations for soldiers, so that they can have more positive oral healthcare practices and attitudes.

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.105-105
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• 2023

Heavy metals, including lead (Pb) toxicity, are increasing in soil and are considered toxic in small amounts. Pb contamination is mainly caused by industrialization - smelting, mining. Agricultural practices - sewage sludge, pests and urban practices - lead paint. It can seriously damage and threaten crop growth. Pb can adversely affect plant growth and development by affecting the photosystem, cell membrane integrity, and excessive production of reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂)andsuperoxide(O₂.-). NO is produced via enzymatic and non-enzymatic antioxidants to scavenge ROS and lipid peroxidation substrates in terms of protecting cells from oxidative damage. Thus, NO improves ion homeostasis and confers resistance to metal stress. Our results here suggest that exogenous NO may aid in better growth under lead stress. These enhancements may be aided by NO's ability in sensing, signaling and stress tolerance in plants under heavy metal stress in combination with lead stress. Our results show that GSNO has a positive effect on soybean seedling growth in response to axillary pressure and that NO supplementation helps to reduce chlorophyll maturation and relative water content in leaves and roots following strong burst under lead stress. GSNO supplementation (200 µM and 100 µM) reduced compaction and approximated oxidative damage of MDA, proline and H₂O₂. Under plant tension, a distorted appearance was found in the relief of oxidative damage by ROS scavenging by GSNO application. In summary, modulation of these NO, PCS and prolongation of metal past reversing GSNO application confirms the detoxification of ROS induced by toxic metal rates in soybean. In summary, these NO, PCS and metal traditionally sustained rates of reverse GSNO application confirm the detoxification of ROS induced by toxic metal rates in soybean.

• Journal of Gifted/Talented Education
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• v.13 no.2
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• pp.73-94
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• 2003

In this study, it was compared how different the adjustment, self-perception, social support and stress between science-gifted children and general children, and the difference between gifted boys and girls. And it was identified what are the effects on stress of science-gifted children. The subjects were 89 science-gifted children of the first grade in Middle School at JeonJu. Science-gifted students in this study were identified through the teacher nomination and CNU(ChonbukNational University) Science & Math Tests. We used the standard object as the comparative group (general children). The results of this study were as follow; First, all personal-adjustment and social-adjustment domains, self-perception and teacher support of science-gifted children were significantly higher than those of general children. All disadjustment domains, parent support and friend support of science-gifted children were significantly lower than those of general children. Second, the self-planning, prejudice, social competence, behavioral conduct, global self worth, parent support, teacher support and classmate support of the science-gifted children had the significant difference according to the gender. Third, the motive of accomplishment, self-planning, attachment and social-affirmation of the science-gifted children correlated negatively with their stress. Fourth, the social competence, athletic competence, physical appearance, behavioral conduct, global self worth and social support of the science-gifted children correlated negatively with their stress. The global self worth of the science-gifted children had the significant difference according to the variables such as teacher support, close friend support, parent support and classmate support in the other of name. The most influential factor was teacher support. The stress of the science-gifted children had the significant difference according to the variables such as parent support, close friend support and global self worth in the other of name. The most influential factor was parent support.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.485-489
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• 1992

Plants are altered not only in the outward appearance but also in their physiological and biochemical properties with reaction to the environmental stresses; particularly, the biosynthetic system of protein in situ rapidly responds to this. In order to investigate the change of properties of polypeptides in rice plants induced by several stresses, the seedlings were subjected to exposure to NaCl, drought, and low and high temperatures, respectively, and then some aspects of polypeptide variations were compared. Without exception, the rice plant, which is somewhat tolerant to environmental change, shows the alteration in several polypeptides. Moreover, newly synthesized polypeptides were observed in response to stresses. The existing proteins for the primary metabolic pathways were markedly decreased as each treatment progressed.

• Research in Community and Public Health Nursing
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• v.29 no.3
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• pp.267-278
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• 2018

Purpose: This study is to investigate working conditions including job stress among visiting nurses in public health centers in Korea. Methods: An social network based mobile survey was conducted in May 2017 (N=936, response rate: 47.0%). Results: The visiting nurses in this study had their average total career as a nurse is 13.7 years. The 68.3% of them were employed in an indefinite term, 17.0% were hired in a fixed term, and 11.0% came from outsourcing. They responded as high job-stress level including inadequate compensation (71.22/100) and job demands (71.91/100). They experienced down-talk (63.4%), swearwords (32.9%), being made a dirty face (39.9%), sexual jokes (30.8%), or being likened or evaluated with their appearance sexually (14.3%). Among the causes of job related conflicts and discrimination, deprived salary level was the most frequent reason (83.4%). The conflicts and discrimination were incurred by government officers (52.4%). There were no significant differences in overall job stress, emotional labor, organizational commitment, violence, and discrimination experience based on their employment types. Conclusion: The differences in working conditions among the non-regular nurses were trivial, and their overall working conditions were poor. It is necessary to improve non-regular nurses' working conditions in order to make up the limitations of the Korean healthcare system which is centered on hospitals.

• Geomechanics and Engineering
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• v.29 no.2
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• pp.113-131
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• 2022

A rockburst is a common disaster in deep-tunnel excavation engineering, especially for high-geostress areas. An anomalously low friction effect is one of the most important inducements of rockbursts. To elucidate the correlation between an anomalously low friction effect and a rockburst, we establish a two-dimensional prediction model that considers the discontinuous structure of a rock mass. The degree of freedom of the rotation angle is introduced, thus the motion equations of the blocks under the influence of a transient disturbing force are acquired according to the interactions of the blocks. Based on the two-dimensional discontinuous block model of deep rock mass, a rockburst prediction model is established, and the initiation process of ultra-low friction rockburst is analyzed. In addition, the intensity of a rockburst, including the location, depth, area, and velocity of ejection fragments, can be determined quantitatively using the proposed prediction model. Then, through a specific example, the effects of geomechanical parameters such as the different principal stress ratios, the material properties, a dip of principal stress on the occurrence form and range of rockburst are analyzed. The results indicate that under dynamic disturbance, stress variation on the structural surface in a deep rock mass may directly give rise to a rockburst. The formation of rockburst is characterized by three stages: the appearance of cracks that result from the tension or compression failure of the deformation block, the transformation of strain energy of rock blocks to kinetic energy, and the ejection of some of the free blocks from the surrounding rock mass. Finally, the two-dimensional rockburst prediction model is applied to the construction drainage tunnel project of Jinping II hydropower station. Through the comparison with the field measured rockburst data and UDEC simulation results, it shows that the model in this paper is in good agreement with the actual working conditions, which verifies the accuracy of the model in this paper.