68 research outputs found
Inter-generational Transitions of Family Businesses using Private Equity: Lessons for China and Australia from Chinese Family-owned Enterprises in Singapore
No full textPi-Shen Seet, Christopher Graves and Wee-Liang Ta
Regulation of the L-type Ca2+ channel during cardiomyogenesis: switch from NO to adenylyl cyclase-mediated inhibition
No full textIn adult mammalian cardiomyocytes, stimulation of muscarinic receptors counterbalances the beta-adrenoceptor-mediated increase in myocardial contractility and heart rate by decreasing the L-type Ca2+ current (ICa) (1, 2). This effect is mediated via inhibition of adenylyl cyclase and subsequent reduction of cAMP-dependent phosphorylation of voltage-dependent L-type Ca2+ channels (3). Little is known, however, about the nature and origin of this pivotal inhibitory pathway. Using embryonic stem cells as an in vitro model of cardiomyogenesis, we found that muscarinic agonists depress ICa by 58 +/-3% (n=34) in early stage cardiomyocytes lacking functional beta-adrenoceptors. The cholinergic inhibition is mediated by the nitric oxide (NO)/cGMP system since it was abolished by application of NOS inhibitors (L-NMA, L-NAME), an inhibitor of the soluble guanylyl cyclase (ODQ), and a selective phosphodiesterase type II antagonist (EHNA). The NO/cGMP-mediated ICa depression was dependent on a reduction of cAMP/protein kinase A (PKA) levels since application of the catalytic subunit of PKA or of the PKA inhibitor PK) prevented the carbachol effect. In late development stage cells, as reported for ventricular cardiomyocytes (2, 4), muscarinic agonists had no effect on basal ICa but antagonized beta-adrenoceptor-stimulated ICa by 43 +/-4% (n=16). This switch in signaling pathways during development is associated with distinct changes in expression of the two NO-producing isoenzymes, eNOS and iNOS, respectively. These findings indicate a fundamental role for NO as a signaling molecule during early embryonic development and demonstrate a switch in the signaling cascades governing ICa regulation
Changing economies for a more sustainable future: the influence of stakeholders and environmental reporting developments in transforming Chinese corporate practices
No full textThe contradictions of developmentalism and the Chinese party-state’s goal of ethnic harmony: the case of Xinjiang
No full textGerry Groo
Sustaining China's media economy: tackling sensationalism and three dilemmas
No full textXie Baohiu and Gao Mob
Microglia Development and Maturation and Its Implications for Induction of Microglia-Like Cells from Human iPSCs
No full textWurm J, Konttinen H, Andressen C, Malm T, Spittau B. Microglia Development and Maturation and Its Implications for Induction of Microglia-Like Cells from Human iPSCs. International Journal of Molecular Sciences. 2021;22(6): 3088.Microglia are resident immune cells of the central nervous system and play critical roles during the development, homeostasis, and pathologies of the brain. Originated from yolk sac erythromyeloid progenitors, microglia immigrate into the embryonic brain parenchyma to undergo final postnatal differentiation and maturation driven by distinct chemokines, cytokines, and growth factors. Among them, TGFβ1 is an important regulator of microglial functions, mediating homeostasis, anti-inflammation, and triggering the expression of microglial homeostatic signature genes. Since microglia studies are mainly based on rodent cells and the isolation of homeostatic microglia from human tissue is challenging, human-induced pluripotent stem cells have been successfully differentiated into microglia-like cells recently. However, employed differentiation protocols strongly vary regarding used cytokines and growth factors, culture conditions, time span, and cell yield. Moreover, the incomplete differentiation of human microglia can hamper the similarity to primary human microglia and dramatically influence the outcome of follow-up studies with these differentiated cells. This review summarizes the current knowledge of the molecular mechanisms driving rodent microglia differentiation in vivo, further compares published differentiation protocols, and highlights the potential of TGFβ as an essential maturation factor
The faster things change, the more they stay the same: the influence of cultural norms, customs and traditions on venture capital in China
No full textZhiqiang Xia, Noel Lindsay, Pi-Shen Seet and Steve Goodma
Oxidation Studies of Alloy 600 in Low Pressure Hydrogenated Steam
No full textThe effect of stress on the oxidation behavior of solution-annealed Alloy 600 was investigated by exposing samples to low pressure steam environments containing hydrogen at temperatures up to 480°C. The resultant oxidized surfaces of stressed and unstressed samples were analyzed via several electron microscopy techniques. For hydrogen partial pressures greater than that corresponding to the Ni/NiO equilibrium, the strain-free surface of Alloy 600 was characterized by the presence of Ni nodules. Detailed Analytical Electron Microscopy (AEM) evaluations of the near-surface regions and grain boundaries were performed on site-specific cross-section specimen produced using the focused ion beam (FIB) technique. High resolution scanning transmission electron microscope (STEM) – energy dispersive x-ray (EDX) microanalysis revealed discrete subsurface oxides, as opposed to a continuous oxide film, thus supporting an internal oxidation process. Furthermore, preferential grain boundary oxide penetration was observed. Although no macroscopic correlation between the magnitude of the residual stress and the surface morphology was detected, local stress measurements using a recently developed FIB micro-hole drilling technique revealed residual stress variations at microscopic level. These results correlated well with the presence of intergranular and internal subsurface oxide
Oxidation Studies of Alloy 600 in Low Pressure Hydrogenated Steam
No full textThe effect of stress on the oxidation behavior of solution-annealed Alloy 600 was investigated by exposing samples to low pressure steam environments containing hydrogen at temperatures up to 480°C. The resultant oxidized surfaces of stressed and unstressed samples were analyzed via several electron microscopy techniques. For hydrogen partial pressures greater than that corresponding to the Ni/NiO equilibrium, the strain-free surface of Alloy 600 was characterized by the presence of Ni nodules. Detailed Analytical Electron Microscopy (AEM) evaluations of the near-surface regions and grain boundaries were performed on site-specific cross-section specimen produced using the focused ion beam (FIB) technique. High resolution scanning transmission electron microscope (STEM) – energy dispersive x-ray (EDX) microanalysis revealed discrete subsurface oxides, as opposed to a continuous oxide film, thus supporting an internal oxidation process. Furthermore, preferential grain boundary oxide penetration was observed. Although no macroscopic correlation between the magnitude of the residual stress and the surface morphology was detected, local stress measurements using a recently developed FIB micro-hole drilling technique revealed residual stress variations at microscopic level. These results correlated well with the presence of intergranular and internal subsurface oxide
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