• 제목/요약/키워드: role stress

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안전관리자 계획단계 업무 도출을 통한 난이도 및 예방효과 분석 (Analysis of Construction Safety Planning Tasks for Performance Improvement Using Importance Performance Analysis (IPA) Method)

  • 강상훈;허영기;김대영
    • 한국건축시공학회지
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    • 제20권6호
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    • pp.545-554
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    • 2020
  • 최근 건설현장에서의 안전사고는 근로자의 생명을 위협하는 중대한 사고로 이어질 수 있는 만큼 안전관리업무를 담당하는 안전관리자의 역할이 대두대고 있다. 그러나 현행 건설업 안전관리에 있어 안전 관리자는 1인당 담당하는 업무량이 과도하게 많고, 비효율적인 안전업무들로 인해 업무내용 개선 및 간략화가 필요한 실정이다. 본 연구의 주목적은 안전 관리자 계획단계에서 수행되는 업무들의 난이도와 예방효과를 전문가 의견을 통해 2×2 Matrix 분석 기법을 활용하여 상관관계를 도출하고 불필요한 업무의 간략화와 업무 개선이 필요한 부분을 파악함으로써, 궁극적으로 건설안전재해사고 발생을 줄이는 데 있다.

FTIR 분자구조 해석을 통한 에폭시-실리카 나노복합소재의 열기계적 물성 연구 (Study on the Thermomechanical Properties of Epoxy-Silica Nanocomposites by FTIR Molecular Structure Analyses)

  • 장서현;한유수;황도순;정주원;김영국
    • 마이크로전자및패키징학회지
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    • 제28권2호
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    • pp.51-57
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    • 2021
  • 이 연구에서는 에폭시 수지에 포함된 나노 실리카 입자의 농도가 재료의 열/기계적 물성에 미치는 영향에 대해 알아보았다. 약 12 nm 크기의 나노 입자를 에폭시 수지에 다섯가지 무게비로 섞은 나노복합소재를 제작하였다. DMA와 TMA 방법을 이용하여 유리전이온도, 응력이완, 열팽창 거동을 측정하였다. 이를 통해 나노입자가 재료의 점탄성 거동에 어떠한 영향을 미치는지 보였다. 실리카 입자의 함량이 증가할수록 순수 에폭시 재료 대비 탄성 물성은 증가하였고, 유리전이온도는 감소하였다. FTIR 결과는 분자구조의 관점에서 충진제 함량에 따른 물성변화의 원인을 찾고 나노입자가 에폭시 분자 구조에 어떠한 영향을 미치는지를 규명하는데 중요한 역할을 하였다.

양성자 조사가 316 스테인리스강의 미세조직과 표면산화 특성에 미치는 영향 (Effects of Proton Irradiation on the Microstructure and Surface Oxidation Characteristics of Type 316 Stainless Steel)

  • 임연수;김동진;황성식;최민재;조성환
    • Corrosion Science and Technology
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    • 제20권3호
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    • pp.158-168
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    • 2021
  • Austenitic 316 stainless steel was irradiated with protons accelerated by an energy of 2 MeV at 360 ℃, the various defects induced by this proton irradiation were characterized with microscopic equipment. In our observations irradiation defects such as dislocations and micro-voids were clearly revealed. The typical irradiation defects observed differed according to depth, indicating the evolution of irradiation defects follows the characteristics of radiation damage profiles that depend on depth. Surface oxidation tests were conducted under the simulated primary water conditions of a pressurized water reactor (PWR) to understand the role irradiation defects play in surface oxidation behavior and also to investigate the resultant irradiation assisted stress corrosion cracking (IASCC) susceptibility that occurs after exposure to PWR primary water. We found that Cr and Fe became depleted while Ni was enriched at the grain boundary beneath the surface oxidation layer both in the non-irradiated and proton-irradiated specimens. However, the degree of Cr/Fe depletion and Ni enrichment was much higher in the proton-irradiated sample than in the non-irradiated one owing to radiation-induced segregation and the irradiation defects. The microstructural and microchemical changes induced by proton irradiation all appear to significantly increase the susceptibility of austenitic 316 stainless steel to IASCC.

Hepatitis B Virus DNA Polymerase Displays an Anti-Apoptotic Effect by Interacting with Elongation Factor-1 Alpha-2 in Hepatoma Cells

  • Niu, Xianli;Nong, Shirong;Gong, Junyuan;Zhang, Xin;Tang, Hui;Zhou, Tianhong;Li, Wei
    • Journal of Microbiology and Biotechnology
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    • 제31권1호
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    • pp.16-24
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    • 2021
  • Hepatitis B virus (HBV) genome P-encoded protein HBV DNA polymerase (Pol) has long been known as a reverse transcriptase during HBV replication. In this study, we investigated the impact of HBV Pol on host cellular processes, mainly apoptosis, and the underlying mechanisms. We showed a marked reduction in apoptotic rates in the HBV Pol-expressed HepG2 cells compared to controls. Moreover, a series of assays, i.e., yeast two-hybrid, GST pull-down, co-immunoprecipitation, and confocal laser scanning microscopy, identified the host factor eEF1A2 to be associated with HBV Pol. Furthermore, knockdown of eEF1A2 gene by siRNA abrogated the HBV Pol-mediated anti-apoptotic effect with apoptosis induced by endoplasmatic reticulum (ER) stress-inducer thapsigargin (TG), thus suggesting that the host factor eEF1A2 is essential for HBV Pol's anti-apoptosis properties. Our findings have revealed a novel role for HBV Pol in its modulation of apoptosis through integrating with eEF1A2.

Single-channel electroencephalography and its associations with anxiety and pain during oral surgery: a preliminary report

  • Jabur, Roberto de Oliveira;Goncalves, Ramon Cesar Godoy;Faria, Kethleen Wiechetek;Semczik, Izabelle Millene;Ramacciato, Juliana Cama;Bortoluzzi, Marcelo Carlos
    • Journal of Dental Anesthesia and Pain Medicine
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    • 제21권2호
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    • pp.155-165
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    • 2021
  • Background: This study aimed to assess the course of anxiety and pain during lower third molar (LTMo) surgery and explore the role of mobile and single-channel electroencephalography under clinical and surgical conditions. Methods: The State-Trait Anxiety Inventory (STAI), Corah's Dental Anxiety Scale (DAS), and Interval Scale of Anxiety Response (ISAR) were used. The patient self-rated anxiety (PSA), the pain felt during and after surgery, EEG, heart rate (HR), and blood pressure (BP) were assessed. Results: The Attention (ATT) and Meditation (MED) algorithms and indicators evaluated in this study showed several associations. ATT showed interactions and an association with STAI-S, pain during surgery, PSA level, HR, and surgical duration. MED showed an interaction and association with DAS, STAI-S, and pain due to anesthesia. Preclinical anxiety parameters may influence clinical perceptions and biological parameters during LTMo surgeries. High STAI-Trait and PSA scores were associated with postoperative pain, whereas high STAI-State scores were associated with more pain during anesthesia and surgery, as well as DAS, which was also associated with patient interference during surgery due to anxiety. Conclusions: The findings suggest that single-channel EEG is promising for evaluating brain responses associated with systemic reactions related to anxiety, surgical stress, and pain during oral surgery.

Green tea polyphenol (-)-epigallocatechin-3-gallate prevents ultraviolet-induced apoptosis in PC12 cells

  • Woo, Su-Mi;Kim, Yoon-Jung;Cai, Bangrong;Park, Sam-Young;Kim, Young;Kim, Ok Joon;Kang, In-Chol;Kim, Won-Jae;Jung, Ji-Yeon
    • International Journal of Oral Biology
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    • 제45권4호
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    • pp.179-189
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    • 2020
  • Green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) is a potent antioxidant with protective effects against neurotoxicity. However, it is currently unclear whether EGCG protects neuronal cells against radiation-induced damage. Therefore, the objective of this study was to investigate the effects of EGCG on ultraviolet (UV)-induced oxidative stress and apoptosis in PC12 cells. The effects of UV irradiation included apoptotic cell death, which was associated with DNA fragmentation, reactive oxygen species (ROS) production, enhanced caspase-3 and caspase-9 activity, and poly (ADP-ribose) polymerase cleavage. UV irradiation also increased the Bax/Bcl-2 ratio and mitochondrial pathway-associated cytochrome c expression. However, pretreatment with EGCG before UV exposure markedly decreased UV-induced DNA fragmentation and ROS production. Furthermore, the UV irradiation-induced increase in Bax/Bcl-2 ratio, cytochrome c upregulation, and caspase-3 and caspase-9 activation were each ameliorated by EGCG pretreatment. Additionally, EGCG suppressed UV-induced phosphorylation of p38 and rescued UV-downregulated phosphorylation of ERK. Taken together, these results suggest that EGCG prevents UV irradiation-induced apoptosis in PC12 cells by scavenging ROS and inhibiting the mitochondrial pathways known to play a crucial role in apoptosis. In addition, EGCG inhibits UV-induced apoptosis via JNK inactivation and ERK activation in PC12 cells. Thus, EGCG represents a potential neuroprotective agent that could be applied to prevent neuronal cell death induced by UV irradiation.

간호학 분야 조직사회화 연구에 대한 체계적 문헌고찰 (A Systematic Review of the Studies on Organizational Socialization)

  • 변진이
    • 융합정보논문지
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    • 제11권3호
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    • pp.77-86
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    • 2021
  • 본 연구는 국내 간호학 분야에서 수행된 조직사회화 관련 연구를 통합하고 분석하기 위해 수행된 체계적 문헌고찰 연구이다. 분석 대상 논문을 검색하게 위하여 '조직사회화' AND '간호'를 주제어로 하였고, 선정기준에 따라 총 26편이 분석에 사용되었다. 간호학 분야의 조직사회화 논문은 2016년부터 증가되기 시작하였고, 26편의 논문은 모두 양적 연구방법인 서술적 조사연구로 수행되었다. 조직사회화 관련 변인에 대한 연구 결과, 조직사회화에 영향을 미치는 변인으로는 회복탄력성, 직무스트레스, 지각된 공정성, 직장 내 괴롭힘, 전문직 자아개념, 조직분위기가 주로 이용되었으며, 조직사회화가 영향을 미치는 결과 변인으로는 이직의도, 재직의도, 회복탄력성, 조직몰입이 있는 것으로 확인되었다. 본 연구는 간호학 분야에서 수행된 조직사회화 관련 연구의 체계적 문헌고찰을 통해 조직사회화 관련 중재연구의 기초 자료로 활용될 수 있다는 점에서 의의가 있다.

The Small GTPase CsRAC1 Is Important for Fungal Development and Pepper Anthracnose in Colletotrichum scovillei

  • Lee, Noh-Hyun;Fu, Teng;Shin, Jong-Hwan;Song, Yong-Won;Jang, Dong-Cheol;Kim, Kyoung Su
    • The Plant Pathology Journal
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    • 제37권6호
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    • pp.607-618
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    • 2021
  • The pepper anthracnose fungus, Colletotrichum scovillei, causes severe losses of pepper fruit production in the tropical and temperate zones. RAC1 is a highly conserved small GTP-binding protein in the Rho GT-Pase family. This protein has been demonstrated to play a role in fungal development, and pathogenicity in several plant pathogenic fungi. However, the functional roles of RAC1 are not characterized in C. scovillei causing anthracnose on pepper fruits. Here, we generated a deletion mutant (𝜟Csrac1) via homologous recombination to investigate the functional roles of CsRAC1. The 𝜟Csrac1 showed pleiotropic defects in fungal growth and developments, including vegetative growth, conidiogenesis, conidial germination and appressorium formation, compared to wild-type. Although 𝜟Csrac1 was able to develop appressoria, it failed to differentiate appressorium pegs. However, 𝜟Csrac1 still caused anthracnose disease with significantly reduced rate on wounded pepper fruits. Further analyses revealed that 𝜟Csrac1 was defective in tolerance to oxidative stress and suppression of host-defense genes. Taken together, our results suggest that CsRAC1 plays essential roles in fungal development and pathogenicity in C. scovilleipepper fruit pathosystem.

Ginsenoside compound K reduces the progression of Huntington's disease via the inhibition of oxidative stress and overactivation of the ATM/AMPK pathway

  • Hua, Kuo-Feng;Chao, A-Ching;Lin, Ting-Yu;Chen, Wan-Tze;Lee, Yu-Chieh;Hsu, Wan-Han;Lee, Sheau-Long;Wang, Hsin-Min;Yang, Ding-I.;Ju, Tz-Chuen
    • Journal of Ginseng Research
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    • 제46권4호
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    • pp.572-584
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    • 2022
  • Background: Huntington's disease (HD) is a neurodegenerative disorder caused by the expansion of trinucleotide CAG repeat in the Huntingtin (Htt) gene. The major pathogenic pathways underlying HD involve the impairment of cellular energy homeostasis and DNA damage in the brain. The protein kinase ataxia-telangiectasia mutated (ATM) is an important regulator of the DNA damage response. ATM is involved in the phosphorylation of AMP-activated protein kinase (AMPK), suggesting that AMPK plays a critical role in response to DNA damage. Herein, we demonstrated that expression of polyQ-expanded mutant Htt (mHtt) enhanced the phosphorylation of ATM. Ginsenoside is the main and most effective component of Panax ginseng. However, the protective effect of a ginsenoside (compound K, CK) in HD remains unclear and warrants further investigation. Methods: This study used the R6/2 transgenic mouse model of HD and performed behavioral tests, survival rate, histological analyses, and immunoblot assays. Results: The systematic administration of CK into R6/2 mice suppressed the activation of ATM/AMPK and reduced neuronal toxicity and mHTT aggregation. Most importantly, CK increased neuronal density and lifespan and improved motor dysfunction in R6/2 mice. Conversely, CK enhanced the expression of Bcl2 protected striatal cells from the toxicity induced by the overactivation of mHtt and AMPK. Conclusions: Thus, the oral administration of CK reduced the disease progression and markedly enhanced lifespan in the transgenic mouse model (R6/2) of HD.

Solidification of uranium mill tailings by MBS-MICP and environmental implications

  • Niu, Qianjin;Li, Chunguang;Liu, Zhenzhong;Li, Yongmei;Meng, Shuo;He, Xinqi;Liu, Xinfeng;Wang, Wenji;He, Meijiao;Yang, Xiaolei;Liu, Qi;Liu, Longcheng
    • Nuclear Engineering and Technology
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    • 제54권10호
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    • pp.3631-3640
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    • 2022
  • Uranium mill tailing ponds (UMTPs) are risk source of debris flow and a critical source of environmental U and Rn pollution. The technology of microbial induced calcium carbonate precipitation (MICP) has been extensively studied on reinforcement of UMTs, while little attention has been paid to the effects of MICP on U & Rn release, especially when incorporation of metakaolin and bacillus subtilis (MBS). In this study, the reinforcement and U & Rn immobilization role of MBS -MICP solidification in different grouting cycle for uranium mill tailings (UMTs) was comprehensively investigated. The results showed that under the action of about 166.7 g/L metakaolin and ~50% bacillus subtilis, the solidification cycle of MICP was shortened by 50%, the solidified bodies became brittle, and the axial stress increased by up to 7.9%, and U immobilization rates and Rn exhalation rates decrease by 12.6% and 0.8%, respectively. Therefore, the incorporation of MBS can enhance the triaxial compressive strength and improve the immobilization capacity of U and Rn of the UMTs bodies solidified during MICP, due to the reduction of pore volume and surface area, the formation of more crystals general gypsum and gismondine, as well as the enhancing of coprecipitation and encapsulation capacity.