• Journal of Magnetics
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• 제10권1호
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• pp.14-22
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• 2005

Precisely refined Mossbauer study and nano structure observation revealed that intergranular phase formed between a-Fe and Nd₂Fe₁₄B phase in NdFeNbB alloys plays a significant role on the magnetic properties. The intergranular interaction was characterized in term of Henkel Plot (δM plot), and hyperfine field, quardrupole splitting and isomer shift were refined to predict the presence and role of the intergranular phase. By the addition of Nb into Nd₈Fe₈₆B₆ composition, coercivity was found to increase by 25% due to the refinement of average grain size of both the soft and hard magnetic phases which was decreased from 50 nm of virgin Nd/sub 8/Fe/sub 86/B/sub 6/ to 25 nm in Nd₈Fe ₈₅Nb₁B₆ alloys. The role of Nb addition was confirmed to stabilize the Nd₂Fe₁₄B lattice preventing from thermal vibration of the corresponding sites substituted Fe by Nb atoms in all sites in the Nd₂Fe₁₄B lattice. The enhanced coercivity was originated from the exchange hardening of soft and amorphous phases surrounding the hard magnetic Nd₂Fe₁₄B crystal.

• 치위생과학회지
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• 제21권4호
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• pp.213-218
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• 2021

Background: The purpose of this study is to identify the gender sensitivity and gender role stereotypes of students in dental hygiene and to provide basic data to expand social awareness of equal gender sensitivity and gender role in dental hygiene and students by identifying the degree of correlation. Methods: The purpose of this study was to study dental hygiene students at colleges in Gyeonggi and Chungcheong areas. The survey was conducted from April 1 to April 30, 2021. The final sample was analyzed on 157 subjects. T-test and ANOVA analysis were performed to compare gender sensitivity and gender role stereotypes according to general characteristics. Equal variances were tested using the Levene statistic, and significant differences between groups were identified through Scheffe's post hoc analysis. Pearson's correlation analysis was performed to confirm the correlation between gender sensitivity and gender role stereotypes. Results: Gender sensitivity was 2.69 and gender role stereotypes were 1.83. Among the sub-areas of gender sensitivity, gender role openness was the highest at 2.86, and non-violence was the lowest at 2.50. As for gender role stereotypes, social stereotypes were the highest among sub-areas at 1.71. Among the general characteristics, there was a statistically significant difference in gender sensitivity according to the presence or absence of opposite sex friends (p=0.011). The gender identity openness of gender sensitivity and the physical sub-areas of gender role stereotypes showed the highest positive correlation(r=0.955). Among the sub-areas of gender sensitivity, gender role openness and domestic stereotypes showed the lowest negative correlation (r=-0.404) among the sub-areas of gender role stereotypes. Conclusion: Dental hygiene students should be able to critically analyze and solve problems of not only sexual violence but also gender discrimination and imbalance in social life. For this, environmental factors such as school education and professor guidance must be strengthened.

• International Journal of Oral Biology
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• 제45권2호
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• pp.58-63
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• 2020

The salivary glands secrete saliva, which plays a role in the maintenance of a healthy oral environment. Under physiological conditions, saliva secretion within the acinar cells of the gland is regulated by stimulation of specific calcium (Ca²⁺) signaling mechanisms such as increases in the intracellular Ca²⁺ concentration ([Ca²⁺]_i) via storeoperated Ca²⁺ entry, which involves components such as Orai1, transient receptor potential (TRP) canonical 1, stromal interaction molecules, and inositol 1,4,5-triphosphate (IP₃) receptors (IP₃Rs). Homer proteins are scaffold proteins that bind to G protein-coupled receptors, IP₃Rs, ryanodine receptors, and TRP channels. However, their exact role in Ca²⁺ signaling in the salivary glands remains unknown. In the present study, we investigated the role of Homer2 in Ca²⁺ signaling and saliva secretion in parotid gland acinar cells under physiological conditions. Deletion of Homer2 (Homer2^-/-) markedly decreased the amplitude of [Ca²⁺]_i oscillations via the stimulation of carbachol, which is physiologically concentrated in parotid acinar cells, whereas the frequency of [Ca²⁺]_i oscillations showed no difference between wild-type and Homer2^-/- mice. Homer2^-/- mice also showed a significant decrease in amylase release by carbachol in the parotid gland in a dose-dependent manner. These results suggest that Homer2 plays a critical role in maintaining [Ca²⁺]_i concentration and secretion of saliva in mouse parotid gland acinar cells.

• 디지털융복합연구
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• 제18권6호
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• pp.501-511
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• 2020

본 연구는 사회복지사 226명을 대상으로 감정노동과 직무스트레스 및 직무성과의 관계를 살펴보았으며 주요 결과를 제시하면 다음과 같다. 첫째, 감정노동 하위개념인 감정표현에 대한 주의 정도는 직무스트레스 하위 개념인 역할갈등에 정적 영향을 미쳤고, 감정적 부조화는 역할과다와 역할갈등에 정적 영향을 미친 것으로 나타났다. 둘째, 감정노동의 하위개념인 감정표현에 대한 주의 정도, 감정적 부조화, 감정노동 빈도 모두는 직무성과 하위개념인 역할과다, 역할갈등, 직무모호성 모두에 통계적으로 유의한 영향을 미치지 못하였다. 셋째, 직무스트레스의 하위개념인 역할과다와 역할갈등은 직무성과의 하위개념인 역할 내 성과와 역할 외 성과 모두에 통계적으로 유의한 부적 영향을 미치는 것으로 나타났다.

• 한국콘텐츠학회논문지
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• 제12권11호
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• pp.539-548
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• 2012

본 연구에서는 보육교사의 역할갈등, 셀프 리더십이 심리적 복지에 미치는 영향에 대하여 연구하였다. 연구대상은 서울과 경기도에 소재한 어린이집 64개를 선정하여 보육교사 260명을 대상으로 상관계수와 중 다회귀분석을 실시하였다. 연구결과는 첫째, 보육교사의 역할갈등, 셀프 리더십, 심리적 복지 간의 관계를 살펴보면, 역할 스트레스와 역할모호성, 행동지향, 건설적 사고는 긍정적 복지가, 역할모호성과 행동지향은 긍정적복지가, 그리고 자연보상과 부정적복지의 하위변인을 제외한 모든 하위영역에서 상관이 있는 것으로 나타났다. 둘째, 중다회귀분석 결과, 심리적 복지에 영향을 미치는 가장 높은 변인은 자연보상, 역할모호성, 그리고 역할스트레스 순으로 나타난 반면, 그 외 모든 하위변인에서는 통계적으로 유의미한 예측변인이 아닌 것으로 나타났다.

• Biomolecules & Therapeutics
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• 제32권3호
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• pp.319-328
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• 2024

Lysophosphatidic acid receptor 1 (LPA₁) plays a critical role in brain injury following a transient brain ischemic stroke. However, its role in permanent brain ischemic stroke remains unknown. To address this, we investigated whether LPA₁ could contribute to brain injury of mice challenged by permanent middle cerebral artery occlusion (pMCAO). A selective LPA₁ antagonist (AM152) was used as a pharmacological tool for this investigation. When AM152 was given to pMCAO-challenged mice one hour after occlusion, pMCAO-induced brain damage such as brain infarction, functional neurological deficits, apoptosis, and blood-brain barrier disruption was significantly attenuated. Histological analyses demonstrated that AM152 administration attenuated microglial activation and proliferation in injured brain after pMCAO challenge. AM152 administration also attenuated abnormal neuroinflammatory responses by decreasing expression levels of pro-inflammatory cytokines while increasing expression levels of anti-inflammatory cytokines in the injured brain. As underlying effector pathways, NF-κB, MAPKs (ERK1/2, p38, and JNKs), and PI3K/Akt were found to be involved in LPA₁-dependent pathogenesis. Collectively, these results demonstrate that LPA₁ can contribute to brain injury by permanent ischemic stroke, along with relevant pathogenic events in an injured brain.

• 간호행정학회지
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• 제17권4호
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• pp.524-537
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• 2011

Purpose: The purpose of this study was to analyze the role performance and related factors of the Clinical Research Coordinator (CRC). Methods: A quantitative, cross-sectional design was used. Data were collected using a structured questionnaire from 134 Clinical Research Coordinators in 4 hospitals and analyzed using descriptive statistics, t-test, ANOVA, and Pearson correlation coefficient. Results: The scores for role performance of CRC were high (average 336.51 points of a possible 420 points, mean average $5.74{\pm}0.67$ of a possible 7) and the degree of role performance in the management task sub dimension (mean average $6.12{\pm}0.77$ of a possible 7) was higher than any other sub dimension. Role performance of the CRC was also related to job satisfaction (r=.198, p=.023). Conclusion: The study results indicate that most CRC are nurses and perceive their role as very important. Further the CRC performance of activities of management task and the Coordination/Advocacy task sub dimension were high and higher levels of job satisfaction were related to higher levels of role performance of CRC was. Therefore, strategies related to improvement in the fringe benefit system and work environment should be developed to increase job satisfaction and thus increase job performance.

• Biomolecules & Therapeutics
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• 제30권6호
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• pp.570-575
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• 2022

Stress breaks body balance, which can cause diverse physiological disorders and worsen preexisting diseases. However, recent studies have reported that controllable stress and overcoming from stress reinforce resilience to resist against more intense stress afterwards. In this study, we investigated the protective effect of corticosterone (CORT), a representative stress hormone against hydrogen peroxide (H₂O₂)-induced neuronal cell death and its underlying molecular mechanism in SH-SY5Y cells, a human neuroblastoma cell line. The decreased cell viability by H₂O₂ was effectively restored by the pretreatment with low concentration of CORT (0.03 μM for 72 h) in the cells. H₂O₂-increased expression of apoptotic markers such as PUMA and Bim was decreased by CORT pretreatment. Furthermore, pretreatment of CORT attenuated H₂O₂-mediated oxidative damages by upregulation of antioxidant enzymes via activation of nuclear factor erythroid 2-related factor 2 (Nrf2). These findings suggest that low concentration of CORT with eustressed condition enhances intracellular self-defense against H₂O₂-mediated oxidative cell death, suggesting a role of low concentration of CORT as one of key molecules for resilience and neuronal cell survival.

• Biomolecules & Therapeutics
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• 제31권6호
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• pp.648-654
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• 2023

Oxidative stress-induced melanocyte apoptosis is linked to the immune system and plays a critical role in the pathogenesis of vitiligo. Aquaporin-3 (AQP3), which is downregulated in vitiligo keratinocytes, regulates intracellular H₂O₂ accumulation. However, the role of AQP3 in oxidative stress is uncertain in vitiligo. This study investigated the effect of downregulated AQP3 on oxidative stress in vitiligo using lesional and non-lesional skin specimen sets from vitiligo patients and primary cultured adult normal human epidermal keratinocytes, with or without downregulation and overexpression of AQP3 in the presence or absence of H₂O₂ treatment. The levels of nuclear factor E2-related factor 2 (NRF2) and/or its main target, NAD(P)H quinone dehydrogenase 1 (NQO-1), were lower in the lesional keratinocytes and cultured keratinocytes with AQP3 knockdown, but were increased in keratinocytes upon AQP3 overexpression. Ratios of NRF2 nuclear translocation and NQO-1 expression levels were further reduced in AQP3-knockdown keratinocytes following H₂O₂ treatment. The conditioned media from AQP3-knockdown keratinocytes treated with H₂O₂ contained higher concentrations of reactive oxygen species (ROS). Moreover, the number of viable melanocytes was reduced when the conditioned media were added to the culture media. Overall, AQP3 downregulation in the keratinocytes of patients with vitiligo can induce oxidative stress in neighboring melanocytes, leading to melanocyte death.

• 한국자기공명학회논문지
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• 제21권2호
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• pp.67-71
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• 2017

At high temperature, the roles of $NH_4$ and $H_2O$ in $(NH_4)_2Fe(SO_4)_2{\cdot}6H_2O$ and $(NH_4)_2Zn(SO_4)_2{\cdot}6H_2O$ single crystals were investigated using a pulse NMR spectrometer. Temperature was shown to have a significant influence, causing changes in the deformation of $NH_4$ and $H_2O$. From the $^1H$ NMR and $^{14}N$ NMR spectrum, the forms of environment surrounding $^{14}N$ in $NH_4$ groups is more important than the loss of $H_2O$ groups. NMR studies indicate that $NH_4{^+}$ ions in Tutton salts play an important role in the changes of the crystal structure at high temperatures.