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Sung Hwan Hong Jeong Tae Kim Jin Man Park Gian Song Wei-Min Wang Ki Buem Kim 《自然科学进展(英文版)》2018,28(6):704-710
Ti_(45)Cu_(40)Ni_7Zr_5Sn_(2.5)Si_(0.5) alloys were prepared under various cooling rate conditions during solidification.The alloys exhibited different volume fractions of B2 particles with 0~40 vol%in an amorphous matrix.Monolithic bulk metallic glass of 1 mm diameter showed no macroscopic plasticity and exhibited the typical vein patterns in a maximum shear stress plane on the fracture surface.However,a bulk metallic glass composite containing the B2 particles revealed obvious plasticity(~5.6%)with a remarkable work-hardening behavior that resulted from a stress-induced martensitic transformation of the B2 particles.Moreover,the composite displayed the complicated fracture morphologies containing of three types of fracture features.Through detailed investigations on the microstructural evolution,mechanical,deformation and fracture characteristics,the influence of B2 particle on overall behavior of the TiCu-based bulk metallic glass composites was elucidated. 相似文献
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Seung-Jae Lee In Hwan Lee Jeong Hun Park So-Jung Gwak Jong-Won Rhie Dong-Woo Cho Tae Jo Ko Dong Sung Kim 《科学通报(英文版)》2009,54(19):3608-3612
We developed a hybrid scaffold and a bioreactor for cartilage regeneration. The hybrid scaffold was developed as combination of two components: a biodegradable framework and hydrogel-containing chondrocytes. We performed the MTT cell proliferation assay to compare the proliferation and viability of chondrocytes on three types of scaffolds: an aiginate gel, the hybrid scaffold, and an alginate sponge. Cells were encapsulated in 2% agarose gel. The bioreactor consisted of a circulation system and a compression system. We performed dynamic cell culture on these agarose gels in the bioreactor for 3 days. 相似文献
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Ho-Chang Jeong Seung-Ju Cho Mi-Ok Lee Hyuk-Jin Cha 《Cellular and molecular life sciences : CMLS》2017,74(14):2601-2611
Despite the recent promising results of clinical trials using human pluripotent stem cell (hPSC)-based cell therapies for age-related macular degeneration (AMD), the risk of teratoma formation resulting from residual undifferentiated hPSCs remains a serious and critical hurdle for broader clinical implementation. To mitigate the tumorigenic risk of hPSC-based cell therapy, a variety of approaches have been examined to ablate the undifferentiated hPSCs based on the unique molecular properties of hPSCs. In the present review, we offer a brief overview of recent attempts at selective elimination of undifferentiated hPSCs to decrease the risk of teratoma formation in hPSC-based cell therapy. 相似文献
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Jeong‐Ryeol Kurz‐Kim 《Journal of forecasting》2008,27(5):419-432
In this paper, we consider a combined forecast using an optimal combination weight in a generalized autoregression framework. The generalized autoregression provides not only a combined forecast but also an optimal combination weight for combining forecasts. By simulation, we find that short‐ and medium‐horizon (as well as partly long‐horizon) forecasts from the generalized autoregression using the optimal combination weight are more efficient than those from the usual autoregression in terms of the mean‐squared forecast error. An empirical application with US gross domestic product confirms the simulation result. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Hyun Woo Choi Jong Soo Kim Hyo Jin Jang Sol Choi Jae-Hwan Kim Hans R. Sch?ler Jeong Tae Do 《Cellular and molecular life sciences : CMLS》2012,69(23):4067-4077
The restricted gene expression pattern of a differentiated cell can be reversed by fusion of the somatic cell with a more developmentally potent cell type, such as an embryonic stem (ES) cell. During this reprogramming process, somatic cells obtain most of the characteristics of pluripotent cells. Reactivation of an inactive X chromosome (Xi) is an important epigenetic marker confirming the pluripotent reprogramming of somatic cells. Female somatic cells contain one active X chromosome (Xa) and one Xi, and following the fusion of these cells with male ES cells, the Xi becomes activated, resulting in XaXaXaY fusion hybrid cells. To monitor Xi reactivation, transgenic female neural stem cells (fNSCs) carrying a green fluorescent protein (GFP) reporter gene expressed on the Xa (X-GFP), but not on the Xi, were used for reprogramming. XaXiGFP NSCs, whose GFP reporter was silenced, were fused with HM1 ES cells (XY) to induce pluripotent reprogramming. The XiGFP of NSCs were found to be activated on day 4 post-fusion, indicating reactivation of the Xi. Hybrid cells showed pluripotent cell-specific characteristics cells including inactivation of the NSC marker Nestin, DNA demethylation of Oct4, DNA methylation of Nestin, and reactivation of the Xi. Following differentiation of the (GFP-positive) hybrid cells through embryoid body formation, the proportion of GFP-negative cells was found to be approximately 26?%, indicating that there was random inactivation of one of the three Xas. Here, we showed that the Xi of somatic cells is reprogrammed to the Xa state and that cellular differentiation occurs randomly, i.e., regardless of the Xa or Xi state, indicating that the memory of the Xi of somatic cells has been erased and reset to the ground state (i.e., inner cell mass-like state), indicating that random X-chromosome inactivation occurs upon differentiation. 相似文献
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Lee JH Huynh M Silhavy JL Kim S Dixon-Salazar T Heiberg A Scott E Bafna V Hill KJ Collazo A Funari V Russ C Gabriel SB Mathern GW Gleeson JG 《Nature genetics》2012,44(8):941-945
De novo somatic mutations in focal areas are well documented in diseases such as neoplasia but are rarely reported in malformation of the developing brain. Hemimegalencephaly (HME) is characterized by overgrowth of either one of the two cerebral hemispheres. The molecular etiology of HME remains a mystery. The intractable epilepsy that is associated with HME can be relieved by the surgical treatment hemispherectomy, allowing sampling of diseased tissue. Exome sequencing and mass spectrometry analysis in paired brain-blood samples from individuals with HME (n = 20 cases) identified de novo somatic mutations in 30% of affected individuals in the PIK3CA, AKT3 and MTOR genes. A recurrent PIK3CA c.1633G>A mutation was found in four separate cases. Identified mutations were present in 8-40% of sequenced alleles in various brain regions and were associated with increased neuronal S6 protein phosphorylation in the brains of affected individuals, indicating aberrant activation of mammalian target of rapamycin (mTOR) signaling. Thus HME is probably a genetically mosaic disease caused by gain of function in phosphatidylinositol 3-kinase (PI3K)-AKT3-mTOR signaling. 相似文献
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This paper seeks to further substantiate and appreciate the importance of West Churchman’s pragmatic philosophy, and to propose
the development of what we call the participatory and rhizomatic systems approach. The aim of rhizomatics is to create a deterritoriazation
of current social fields and to make sense of the creation of the rhizomatic networks and ethics for the marginalized group
in practice. This paper takes the contributions of Gilles Deleuze and Felix Guattari’s notion of rhizome on ethical reasoning
and incorporates them into a test. It examines how ethics for the marginalized group can assist in appreciating and developing
ethical management of any systemic intervention. The paper looks into what ethics for the marginalized group is and how it
is achieved in the context of rhizomatic networks.
相似文献
Jae Eon YuEmail: |