• 제목/요약/키워드: Challenge Stress

검색결과 183건 처리시간 0.021초

관상동맥 분지관에서 점도에 따른 유체의 유동현상 연구 (A Study on Fluid Flow of Various Viscosities in Coronary Artery)

  • 안기영;이현섭
    • EDISON SW 활용 경진대회 논문집
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    • 제2회(2013년)
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    • pp.403-408
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    • 2013
  • 본 논문은 EDISON_CFD를 이용하여 관상동맥 분지관에서 점도에 따른 유체의 유동현상에 관하여 연구를 하였다. 뉴턴유체인 물의 점성계수 일때와 비뉴턴유체인 혈액의 Carreau model에서의 영전단율 점성계수(${\eta}_0$)와 무한전단율 점성계수(${\eta}_{\infty}$)일 때의 유동현상을 살펴보았다. 그 결과 점도가 증가할수록 재순환 영역에서 유체의 속도가 감소하였고 CF 및 CP값이 감소하는 구간의 수가 증가하여 벽면의 저전단응력으로 인해 생기는 재순환영역의 수가 증가하는 것으로 나타났다.

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Optical Stimulation and Pacing of the Embryonic Chicken Heart via Thulium Laser Irradiation

  • Chung, Hong;Chung, Euiheon
    • Current Optics and Photonics
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    • 제3권1호
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    • pp.1-7
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    • 2019
  • Optical stimulation provides a promising alternative to electrical stimulation to selectively modulate tissue. However, developing noninvasive techniques to directly stimulate excitable tissue without introducing genetic modifications and minimizing cellular stress remains an ongoing challenge. Infrared (IR) light has been used to achieve optical pacing for electrophysiological studies in embryonic quail and mammalian hearts. Here, we demonstrate optical stimulation and pacing of the embryonic chicken heart using a pulsed infrared thulium laser with a wavelength of 1927 nm. By recording stereomicroscope outputs and quantifying heart rates and movements through video processing, we found that heart rate increases instantly following irradiation with a large spot size and high radiant exposure. Targeting the atrium using a smaller spot size and lower radiant exposure achieved pacing, as the heart rate synchronized with the laser to 2 Hz. This study demonstrates the viability of using the 1927 nm thulium laser for cardiac stimulation and optical pacing, expanding the optical parameters and IR lasers that can be used to modulate cardiac dynamics.

Psychological Aspects of Child Maltreatment

  • Ahn, Yebin D.;Jang, Soomin;Shin, Jiyoon;Kim, Jae-Won
    • Journal of Korean Neurosurgical Society
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    • 제65권3호
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    • pp.408-414
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    • 2022
  • In this review, we provide information about the etiology, risk factors, and clinical presentations of maltreatment to help clinicians better understand child abuse and neglect. Child maltreatment is a major global health challenge that can result in severe consequences. Abused and neglected children are likely to develop psychiatric disorders, such as major depressive disorder, anxiety disorder, and posttraumatic stress disorder. Understanding child maltreatment is expected to prevent and reduce victimization in children, adolescents, and their families.

Fusion Peptide Improves Stability and Bioactivity of Single Chain Antibody against Rabies Virus

  • Xi, Hualong;Zhang, Kaixin;Yin, Yanchun;Gu, Tiejun;Sun, Qing;Shi, Linqing;Zhang, Renxia;Jiang, Chunlai;Kong, Wei;Wu, Yongge
    • Journal of Microbiology and Biotechnology
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    • 제27권4호
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    • pp.718-724
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    • 2017
  • The combination of rabies immunoglobulin (RIG) with a vaccine is currently effective against rabies infections, but improvements are needed. Genetic engineering antibody technology is an attractive approach for developing novel antibodies to replace RIG. In our previous study, a single-chain variable fragment, scFv57R, against rabies virus glycoprotein was constructed. However, its inherent weak stability and short half-life compared with the parent RIG may limit its diagnostic and therapeutic application. Therefore, an acidic tail of synuclein (ATS) derived from the C-terminal acidic tail of human alpha-synuclein protein was fused to the C-terminus of scFv57R in order to help it resist adverse stress and improve the stability and half-life. The tail showed no apparent effect on the preparation procedure and affinity of the protein, nor did it change the neutralizing potency in vitro. In the ELISA test of molecular stability, the ATS fusion form of the protein, scFv57R-ATS, showed an increase in thermal stability and longer half-life in serum than scFv57R. The protection against fatal rabies virus challenge improved after fusing the tail to the scFv, which may be attributed to the improved stability. Thus, the ATS fusion approach presented here is easily implemented and can be used as a new strategy to improve the stability and half-life of engineered antibody proteins for practical applications.

Characterization of Copper/Zinc-Superoxide Dismutase (Cu/Zn-SOD) Gene from an Endangered Freshwater Fish Species Hemibarbus mylodon (Teleostei; Cypriniformes)

  • Lee, Sang-Yoon;Kim, Keun-Yong;Bang, In-Chul;Nam, Yoon-Kwon
    • Fisheries and Aquatic Sciences
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    • 제14권1호
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    • pp.43-54
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    • 2011
  • Gene structure of copper/zinc-superoxide dismutase (Cu/Zn-SOD; sod1) was characterized in Hemibarbus mylodon (Teleostei; Cypriniformes), an endangered freshwater fish species in Korean peninsula. Full-length cDNA of H. mylodon SOD1 consisted of a 796-bp open reading frame sequence encoding 154 amino acids, and the deduced polypeptide sequence shared high sequence homology with other orthologs, particularly with regard to metal-coordinating ligands. Genomic structure of the H. mylodon sod1 gene (hmsod1; 1,911 bp from the ATG start codon to the stop codon) was typical quinquepartite (i.e., five exons interrupted by four introns); the lengths of the exons were similar among species belonging to various taxonomic positions. The molecular phylogeny inferred from sod1 genes in the teleost lineage was in accordance with the conventional taxonomic assumptions. 5'-flanking upstream region of hmsod1, obtained using the genome walking method, contained typical TATA and CAAT boxes. It also showed various transcription factor binding motifs that may be potentially involved in stress/immune response (e.g., sites for activating proteins or nuclear factor kappa B) or metabolism of xenobiotic compounds (e.g., xenobiotic response element; XRE). The hmsod1 transcripts were ubiquitously detected among tissues, with the liver and spleen showing the highest and lowest expression, respectively. An experimental challenge with Edwardsiella tarda revealed significant upregulation of the hmsod1 in kidney (4.3-fold) and spleen (3.1-fold), based on a real-time RT-PCR assay. Information on the molecular characteristics of this key antioxidant enzyme gene could be a useful basis for a biomarker-based assay to understand cellular stresses in this endangered fish species.

Effects of Chromium Propionate Supplementation on Growth Performance, Serum Traits and Immune Response in Weaned Pigs

  • Lien, T.-F.;Yang, K.-H.;Lin, K.-J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제18권3호
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    • pp.403-408
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    • 2005
  • This study investigated the effects of chromium propionate on growth performance, serum traits and immune response in weaned pigs. Twenty-four 4 wk-old crossbred weanling pigs (initial body weight about 9.52${\pm}$0.48 kg) were randomly allotted into one of two groups, a control group (basal diet), chromium propionate group (diet supplemented with 200 ${\mu}g$ $kg^{-1}$ (ppb) of chromium propionate). This experiment was conducted over nine weeks. Escherichia coli lipopolysaccharide (LPS) 100 ${\mu}g$ $kg^{-1}$ BW was used as the stress-inducing agent in the middle (4 wks) and final (8 wks) periods. The experimental results indicated that chromium propionate had no effect on growth performance (p>0.05). Chromium propionate supplementation reduced the percentage of LDL+VLDL (low and very low-density lipoprotein) and increased HDL (high-density lipoprotein), but did not affect other serum traits. Pigs supplemented with chromium propionate had higher antibody titers specific for sheep red blood cells (SRBC) and serum total globulin relative to the control during the final period (p<0.05). A challenge with LPS increased white blood cells in the chromium propionate group in both experimental periods (p<0.05). The chromium propionate group exhibited higher IgG and $\gamma$-globulin than the control during the middle experimental period (p<0.05). Moreover, the PHA (phytohemagglutinin) challenge result in the chromium propionate group was better than the control group (p=0.056). Greater neutrophil activity was displayed than in the control (p<0.05). This suggests that chromium propionate supplementation benefited the weaned pigs in lipoprotein and immune response.

Molecular characterization and expression of suppressor of cytokine signaling (SOCS) 1, 2 and 3 under acute hypoxia and reoxygenation in pufferfish, Takifugu fasciatus

  • Wang, Dan;Wen, Xin;Zhang, Xinyu;Hu, Yadong;Li, Xinru;Zhu, Wenxu;Wang, Tao;Yin, Shaowu
    • Genes and Genomics
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    • 제40권11호
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    • pp.1225-1235
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    • 2018
  • Hypoxia seriously affects the innate immune system of fish. However, the roles of suppressor of cytokine signaling (SOCS), pivotal anti-inflammatory genes, in response to hypoxia/reoxygenation remain largely unexplored. The primary objective of this study was to elucidate the function of SOCS genes under acute hypoxia and reoxygenation in pufferfish (Takifugu fasciatus). In the present study, SOCS1, 2 and 3 were identified in T. fasciatus referred to as TfSOCS1, 2 and 3. Then, qRT-PCR and western blot analysis were employed to assess their expressions at both the mRNA and protein levels. Tissue distribution demonstrated that the three SOCS genes were predominantly distributed in gill, brain and liver. Under hypoxia challenge ($1.63{\pm}0.2mg/L$ DO for 2, 4, 6 and 8 h), the expressions of TfSOCS1 and 3 in brain and liver at the mRNA and protein levels were significantly decreased, while their expressions showed an opposite trend in gill. Different from the expressions of TfSOCS1 and 3, the expression of TfSOCS2 was inhibited in gill, along with its increased expression in brain and liver. After normoxic recovery ($7.0{\pm}0.3mg/L$ of DO for 4 and 12 h), most of TfSOCS genes were significantly altered at R4 (reoxygenation for 4 h) and returned to the normal level at R12 (reoxygenation for 12 h). SOCS genes played vital roles in response to hypoxia/reoxygenation challenge. Our findings greatly strengthened the relation between innate immune and hypoxia stress in T. fasciatus.

판 내부 융기 운동의 다양한 스케일과 매커니즘 (Various vertical motions and mechanisms in intraplate settings)

  • 신재열
    • 한국지형학회지
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    • 제19권3호
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    • pp.153-163
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    • 2012
  • 지구 지표는 암석권 내 혹은 암석권 하부의 다양한 동적 원인에 의해 수직적으로 변형될 수 있으나, 판 내부 지역에서 발생하는 다양한 수직적 지각 변형의 원인과 매커니즘을 구분해내는 일은 여전히 지구과학 분야에 있어 기초적인 도전의 영역으로 남아있다. 이러한 과학적 도전에 있어 가장 중요한 전제 조건은 다양한 지구조 환경에서의 보다 많은 대륙 지각 변형 사건들을 파악하고 시 공간적 패턴을 구분해보는 일이 될 것이다. 본 연구는 최근의 연구 성과들에 바탕하여 한반도의 신생대 신제3기 이후 융기 운동을 포함한 판 내부 대륙 지각에서 발생하는 다양한 수직적 변형 사건들의 다양한 지구역학적 요인들을 설명하고자 하는데 그 목적을 두고 있다. 궁극적으로 지구지표 형태와 지구 내부 활동간의 상호작용에 대한 이해는 지구 내부 활동의 다양한 신호들을 보여주는 이상적인 프리즘으로서 지표 지형의 중요성을 보여 줄 것으로 확신한다.

The Correlation between NaCl Adaptation and Heat Sensitivity of Listeria monocytogenes, a Foodborne Pathogen through Fresh and Processed Meat

  • Lee, Jeeyeon;Ha, Jimyeong;Kim, Sejeong;Lee, Soomin;Lee, Heeyoung;Yoon, Yohan;Choi, Kyoung-Hee
    • 한국축산식품학회지
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    • 제36권4호
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    • pp.469-475
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    • 2016
  • This study examined the relationship between NaCl sensitivity and stress response of Listeria monocytogenes. Nine strains of L. monocytogenes (NCCP10805, NCCP10806, NCCP10807, NCCP10808, NCCP10809, NCCP10810, NCCP10811, NCCP10920 and NCCP 10943) were exposed to 0%, 1%, 2% and 4% NaCl, and then incubated at 60℃ for 60 min to select strains that were heat-sensitized (HS) and non-sensitized (NS) by NaCl exposure. After heat challenge, L. monocytogenes strains were categorized as HS (NCCP 10805, NCCP10806, NCCP10807, NCCP10810, NCCP10811 and NCCP10920) or NS (NCCP10808, NCCP10809 and NCCP10943). Total mRNA was extracted from a HS strain (NCCP10811) and two NS strains (NCCP10808 and NCCP10809), and then cDNA was prepared to analyze the expression of genes (inlA, inlB, opuC, betL, gbuB, osmC and ctc) that may be altered in response to NaCl stress, by qRT-PCR. The expression levels of two invasion-related genes (inlA and inlB) and two stress response genes (opuC and ctc) were increased (p<0.05) in NS strains after NaCl exposure in an NaCl concentration-dependent manner. However, only betL expression was increased (p<0.05) in the HS strains. These results indicate that the effect of NaCl on heat sensitization of L. monocytogenes is strain dependent and that opuC and ctc may prevent NS L. monocytogenes strains from being heat sensitized by NaCl. Moreover, NaCl also increases the expression of invasion-related genes (inlA and inlB).

가스공급배관에서 응력부식균열 군에 의해 교란된 자속의 유한요소 모델링 (Finite Element Modeling of Perturbation Fields due to Colonies of Stress Corrosion Cracks(SCCs) in a Gas Transmission Pipeline)

  • 양선호
    • 비파괴검사학회지
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    • 제21권5호
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    • pp.493-500
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    • 2001
  • 기존의 누설자속 탐상용 pig를 이용한 가스배관 검사시 축 방향 길함의 검출은 매우 어렵다. 본 논문에서는 원주 방향의 전류와 축 방향 응력부식균열(SCC)의 상호작용을 이용한 새로운 기술을 소개한다. 이 방법의 타당성은 유한요소법을 통하여 연구하였는데, 이러한 상호작용의 유한요소 해석은 재료의 비선형성, 무체적성 균열의 작은 크기, 속도 효과를 고려한 시간 단계별 계산등으로 인한 컴퓨터성능 제한으로 매우 어렵다. 이 논문에서는 이 문제점을 해결하기 위해 교란방법(perturbation method)을 이용한 새로운 방법을 제시하였다. 전체 해석과정은 순차적으로 수행할 수 있는 4개의 간단한 과정들로 나누어 수행하였다. 모델링 결과는 이 방법이 하나의 SCC 또는 여러 개가 존재하는 SCC 군을 효과적으로 검출 할 수 있음을 보여 주었다.

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