• 제목/요약/키워드: Critical levels

검색결과 1,342건 처리시간 0.031초

Interaction of internal forces of exterior beam-column joints of reinforced concrete frames under seismic action

  • Zhou, Hua;Zhang, Zhisheng
    • Structural Engineering and Mechanics
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    • 제44권2호
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    • pp.197-217
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    • 2012
  • Detailed analysis of internal forces of exterior beam-column joints of RC frames under seismic action is reported in this paper. A formula is derived for calculating the average joint shear from the column shears, and a formula is proposed to estimate torque in eccentric joints induced by seismic action. Average joint shear stress and strain are defined consistently for exterior joints, which can be used to establish joint shear constitutive relationship. Numerical results of shear, bending moment and torque in joints induced by seismic action are presented for a pair of concentric and eccentric exterior connections extracted from a seismically designed RC frame, and two sections located at the levels of beam bottom and top reinforcement, respectively, are identified as the critical joint sections for evaluating seismic joint behavior. A simplified analysis of the effects of joint shear and torque on the flexural strengths of the critical joint sections is made for the two connections extracted from the frame, and the results indicate that joint shear and torque induced by a strong earthquake may lead to "joint-hinging" mechanism of seismically designed RC frames.

Expression of Progranulin in Early and Late Gestation Human Placentas

  • Ka Hak-Hyun
    • Reproductive and Developmental Biology
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    • 제30권2호
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    • pp.107-113
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    • 2006
  • Development of placenta is a complex process that is critical for the pregnancy and controlled by many factors including cytokines, hormones, growth factors and apoptotic molecules. Recently, it has been shown that progranulin (PGRN) functions in growth of embryo and trophectoderm as well as cell migration. To initiate understanding the role of PGRN in human placental development, we investigated the expression of PGRN mRNA and protein in early and late gestation human placentas, term cytotrophoblast cells and two choriocarcinoma cell lines, JEG-3 and Jar. Reverse transcriptase polymerase chain reaction identified mRNAs derived from the PGRN gene in all samples. Immunoblot analysis showed that PGRN proteins are present in early and late gestation human placentas with decreasing levels over gestation and that PGRN proteins are present in normal and transformed trophoblast cells. Immunohistochemical analysis using paraformaldehyde-fixed tissue sections taken from early and late stages of pregnancy showed that PGRN proteins are present in cytotrophoblast cells, syncytiotrophoblast and extravillous cytotrophoblast cells and that expression pattern of PGRN differed according to the stage of cell differentiation. The results of this study are consistent with the hypothesis that PGRN proteins have critical roles in placental development and suggest that PGRN may function in trophoblast cell growth and differentiation.

Immunostimulatory Effects of ${\beta}$-glucan Purified from Paenibacillus polymyxa JB115 on Mouse Splenocytes

  • Kim, Ji-Mi;Joo, Hong-Gu
    • The Korean Journal of Physiology and Pharmacology
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    • 제16권4호
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    • pp.225-230
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    • 2012
  • We investigated the effects of ${\beta}$-glucan purified from Paenibacillus polymyxa JB115 on the viability and proliferation of splenocytes. Splenocytes play a critical role in host immunity. MTT assays and trypan blue exclusion tests revealed that ${\beta}$-glucan significantly promoted the viability and proliferation of splenocytes over a range of concentrations. However, there was no specific subset change. ${\beta}$-glucan protected splenocytes from cytokine withdrawal-induced spontaneous cell death. For further mechanistic studies, ELISA assay revealed that ${\beta}$-glucan enhanced the expression of anti-apoptotic molecules and interleukin 7 (IL-7), a cytokine critical for lymphocyte survival. We also investigated the IL-2 dependency of ${\beta}$-glucan-treated splenocytes to determine if treated cells could still undergo clonal expansion. In flow cytometric analysis, ${\beta}$-glucan induced increased levels of the activation marker CD25 on the surface of splenocytes and ${\beta}$-glucan-treated splenocytes showed higher proliferation rates in response to IL-2 treatment. This study demonstrates that ${\beta}$-glucan can enhance the survival of splenocytes and provides valuable information to broaden the use of ${\beta}$-glucan in research fields.

림프부종 자가 관리 실천 정도와 유방절제술 환자의 삶의 질과의 관계 (The Relationship between Practice in Lymphedema Self-care Management and Health-related Quality of Life in Breast Cancer Patients with Mastectomy)

  • 최은녀;최혜란
    • 중환자간호학회지
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    • 제6권1호
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    • pp.21-33
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    • 2013
  • Purpose: The purpose of this study was to examine the relationship between lymphedema self-care management and quality of life in breast cancer patients with mastectomy and lymphedema. Methods: One hundred and eighty-six breast cancer patients with mastectomy and lymphedema (n=186) were recruited at a medical center located in Seoul. The levels of lymphedema self-care management and quality of life were measured by the scale for measurement of practice in lymphedema self-care management, European Organization for Research and Treatment of Cancer-Quality of Life Core 30 (EORTC QLQ-C30) and European Organization for Research and Treatment of Cancer-Quality of Life Questionnaire Breast Cancer Module (EORTC QLQ BR23), respectively. Data were analyzed with SPSS 18.0 program. Results: There were statistically significant correlations between lymphedema self-care management and general health status/quality of life in mastectomy patients with lymphedema (r=.30, p<.001). The physical function score of cancer related function scale (r=-.15, p=.033), fatigue score of cancer related symptom scale (r=.15, p=.036), systemic side effect score of breast cancer related symptom scale (r=.45, p=.034), and upset by hair loss (r=.27, p=.004) were significantly correlated with quality of life. Conclusion: The findings suggest that these significant factors should be considered when caring for lymphedema patients.

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심폐소생술 교육이 간호학과 학생의 심폐소생술에 대한 지식, 태도 및 지각한 수행능력에 미치는 효과 (The Effects of CPR Training for Nursing Students on their Knowledge, Attitude, and Perceived Competence)

  • 박영례;김진아;최경숙;김금순
    • 중환자간호학회지
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    • 제1권1호
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    • pp.7-17
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    • 2008
  • Purpose: The purpose of this study was to determine the effects of CPR training for nursing students on their knowledge, attitude and perceived competence. Methods: This study was a nonequivalent control group pretest-posttest design. The participants were 54 nursing students who were conveniently assigned to an experimental or control group. The data was collected from October 22 to November 20, 2007 and analyzed by using $x^2$-test and t-test. Results: The first hypothesis,“Posttest CPR knowledge scores in the experimental group will be higher than those in the control group”was supported(t=4.257, p=.000). The second hypothesis,“Posttest CPR attitude scores in the experimental group will be higher than those in the control group” was supported(t=3.664, p=.001). The third hypothesis,“Posttest CPR perceived competence scores in the experimental group will be higher than those in the control group”was supported(t=6.49, p=.000). Conclusion: The CPR training was the effective strategic method to increase the levels of knowledge, attitude, and perceived competence for nursing students.

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Inhibition of melanogenesis by tyrosinase siRNA in human melanocytes

  • An, Sang-Mi;Koh, Jae-Sook;Boo, Yong-Chool
    • BMB Reports
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    • 제42권3호
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    • pp.178-183
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    • 2009
  • Tyrosinase (TYR) plays a critical role in cellular melanogenesis and, thus, has been the major target of pharmacological approaches for the control of skin pigmentation. This study examined an alternative molecular approach using TYR-small interfering RNA (siRNA) to control melanogenesis in the human melanocytes. Both the mRNA and protein levels of TYR were significantly lowered by TYR-siRNA treatment, whereas TYR-related protein 1 and TYR-related protein 2 displayed no such changes. TYR-siRNA treatment inhibited the cellular melanin synthesis from the externally supplied TYR substrate L-tyrosine. TYR-siRNA also suppressed melanin synthesis and decreased the viability of cells exposed to ultraviolet radiation, supporting a critical role of melanin in protection against ultraviolet radiation. These results suggest that molecular approaches using siRNA targeted to the enzymes of melanogenic pathway may provide a novel strategy for the control of cell pigmentation.

Perspectives provided by leopard and other cat genomes: how diet determined the evolutionary history of carnivores, omnivores, and herbivores

  • Kim, Soonok;Cho, Yun Sung;Bhak, Jong;O'Brian, Stephen J.;Yeo, Joo-Hong
    • BMB Reports
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    • 제50권1호
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    • pp.3-4
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    • 2017
  • Recent advances in genome sequencing technologies have enabled humans to generate and investigate the genomes of wild species. This includes the big cat family, such as tigers, lions, and leopards. Adding the first high quality leopard genome, we have performed an in-depth comparative analysis to identify the genomic signatures in the evolution of felid to become the top predators on land. Our study focused on how the carnivore genomes, as compared to the omnivore or herbivore genomes, shared evolutionary adaptations in genes associated with nutrient metabolism, muscle strength, agility, and other traits responsible for hunting and meat digestion. We found genetic evidence that genomes represent what animals eat through modifying genes. Highly conserved genetically relevant regions were discovered in genomes at the family level. Also, the Felidae family genomes exhibited low levels of genetic diversity associated with decreased population sizes, presumably because of their strict diet, suggesting their vulnerability and critical conservation status. Our findings can be used for human health enhancement, since we share the same genes as cats with some variation. This is an example how wildlife genomes can be a critical resource for human evolution, providing key genetic marker information for disease treatment.

니스타틴의 응집 특성 및 용혈 활성 (The Aggregation State and Hemolytic Activity of Nystatin)

  • 유봉규
    • Journal of Pharmaceutical Investigation
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    • 제31권1호
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    • pp.1-5
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    • 2001
  • The aggregation behavior of nystatin (NYS) in the presence of pluronic F127, triblock copolymer of poly (ethylene oxide) (PEO) and poly (propylene oxide) (PPO), was measured and correlated with hemolytic activity. Antifungal activity was also studied using Saccharomyces cerevisiae as a model strain. The critical aggregation concentrations (CAC) of the drug were 50.1, 108.0, 134.2, 154.3, and $217.9\;{\mu}M$ at 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% pluronic F127 solution, respectively. The levels of NYS required to start lysis of erythrocytes were about 80, 100, 125, 150, and $200\;{\mu}M$ at 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% pluronic F127 solution, respectively. It was $50\;{\mu}M$ in the absence of the polymer. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of NYS-pluronic F127 lyophilizate were same at $3\;{\mu}g/ml$, while MIC and MFC of pure NYS are $3\;{\mu}g/ml$ and $12\;{\mu}g/ml$, respectively. By modulating the aggregation behavior of NYS, pluronic F127 was able to reduce the toxicity of the drug without compromising the MIC and MFC.

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Influences of Bending Temperature on the I$_{c}$ Degradation Behavior of Bi-2223 tapes under Bending

  • Shin Hyung Seop;Dizon John Ryan C.;Katagiri Kazumune;Kuroda Tsuneo
    • 한국초전도ㆍ저온공학회논문지
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    • 제7권2호
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    • pp.11-15
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    • 2005
  • The I$_{c}$ degradation behavior of Bi-2223 tapes bent at RT and 77K were investigated using the bending device invented by Goldacker. Test results on fixing the tape at RT and 17K showed no difference. At 17K and RT bending, the critical strain was 0.67 and 0.50$\%$, respectively, for the VAM-l tape. For the AMSC tape, it was 0.94 and 0.88$\%$, respectively. These results show that there is additional residual stress in the superconducting filaments to be bent at 17K which shifts the formation of cracks into smaller bending radii. This was proved by computational analysis based on the mixture rule of composites. For the VAM-l tape, the Ie degradation behavior using the Goldacker type device shifted to higher strain levels at about 0.5$\%$, as compared with the FRP sample holders which have a critical bending strain of about 0.24$\%$. Also, for the externally reinforced AMSC tape, Ie degradation using the Goldacker type device begins at a higher strain level, at 0.88$\%$ as compared with using FRP sample holders, at 0.74$\%$. The difference between both cases can be explained by the tensile' and thermal stresses that the tapes were subjected to during fixing (soldering) when the FRP sample holders were used.

Regulator of Calcineurin (RCAN): Beyond Down Syndrome Critical Region

  • Lee, Sun-Kyung;Ahnn, Joohong
    • Molecules and Cells
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    • 제43권8호
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    • pp.671-685
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    • 2020
  • The regulator of calcineurin (RCAN) was first reported as a novel gene called DSCR1, encoded in a region termed the Down syndrome critical region (DSCR) of human chromosome 21. Genome sequence comparisons across species using bioinformatics revealed three members of the RCAN gene family, RCAN1, RCAN2, and RCAN3, present in most jawed vertebrates, with one member observed in most invertebrates and fungi. RCAN is most highly expressed in brain and striated muscles, but expression has been reported in many other tissues, as well, including the heart and kidneys. Expression levels of RCAN homologs are responsive to external stressors such as reactive oxygen species, Ca2+, amyloid β, and hormonal changes and upregulated in pathological conditions, including Alzheimer's disease, cardiac hypertrophy, diabetes, and degenerative neuropathy. RCAN binding to calcineurin, a Ca2+/calmodulin-dependent phosphatase, inhibits calcineurin activity, thereby regulating different physiological events via dephosphorylation of important substrates. Novel functions of RCANs have recently emerged, indicating involvement in mitochondria homeostasis, RNA binding, circadian rhythms, obesity, and thermogenesis, some of which are calcineurin-independent. These developments suggest that besides significant contributions to DS pathologies and calcineurin regulation, RCAN is an important participant across physiological systems, suggesting it as a favorable therapeutic target.