Upregulated sirtuin 1 by miRNA-34a is required for smooth muscle cell differentiation from pluripotent stem cells

© 2015 Macmillan Publishers Limited. All rights reserved. microRNA-34a (miR-34a) and sirtuin 1 (SirT1) have been extensively studied in tumour biology and longevityaging, but little is known about their functional roles in smooth muscle cell (SMC) differentiation from pluripotent stem cells. Using well-established SMC differentiation models, we have demonstrated that miR-34a has an important role in SMC differentiation from murine and human embryonic stem cells. Surprisingly, deacetylase sirtuin 1 (SirT1), one of the top predicted targets, was positively regulated by miR-34a during SMC differentiation. Mechanistically, we demonstrated that miR-34a promoted differentiating stem cells' arrest at G0G1 phase and observed a significantly decreased incorporation of miR-34a and SirT1 RNA into Ago2-RISC complex upon SMC differentiation. Importantly, we have identified SirT1 as a transcriptional activator in the regulation of SMC gene programme. Finally, our data showed that SirT1 modulated the enrichment of H3K9 tri-methylation around the SMC gene-promoter regions. Taken together, our data reveal a specific regulatory pathway that miR-34a positively regulates its target gene SirT1 in a cellular context-dependent and sequence-specific manner and suggest a functional role for this pathway in SMC differentiation from stem cells in vitro and in vivo

A study of manufacturing tubes with nano/ultrafine grain structure by stagger spinning

A new method of manufacturing tubes with nano/ultrafine grain structure by stagger spinning and recrystallization annealing is proposed in this study. Two methods of the stagger spinning process are developed, the corresponding macroforming quality, microstructural evolution and mechanical properties of the spun tubes made of ASTM 1020 steel are analysed. The results reveal that a good surface smoothness and an improved spin-formability of spun parts can be obtained by the process combining of 3-pass spinning followed by a 580 °C × 0.5 h static recrystallization and 2-pass spinning with a 580 °C × 1 h static recrystallization annealing under the severe thinning ratio of wall thickness reduction. The ferritic grains with an average initial size of 50 μm are refined to 500 nm after stagger spinning under the 87% thinning ratio of wall thickness reduction. The equiaxial ferritic grains with an average size of 600 nm are generated through re-nucleation and grain growth by subsequent recrystallization annealing at 580 °C for 1 h heat preservation. The tensile strength of spun tubes has been founded to be proportional to the reciprocal of layer spacing of pearlite (LSP), and the elongation is inversely proportional to the reciprocal of LSP. This study shows that the developed method of stagger power spinning has the potential to be used to manufacture bulk metal components with nano/ultrafine grain structure

Correlations among superconductivity, structural instability, and band filling in Nb1-xB2 at the critical point x=0.2

We performed an extensive investigation on the correlations among superconductivity, structural instability and band filling in Nb1-xB2 materials. Structural measurements reveal that a notable phase transformation occurs at x=0.2, corresponding to the Fermi level (EF) in the pseudogap with the minimum total density of states (DOS) as demonstrated by the first-principles calculations. Superconductivity in Nb1-xB2 generally becomes visible in the Nb-deficient materials with x=0.2. Electron energy-loss spectroscopy (EELS) measurements on B K-edge directly demonstrated the presence of a chemical shift arising from the structural transformation. Our systematical experimental results in combination with theoretical analysis suggest that the emergence of hole states in the sigma-bands plays an important role for understanding the superconductivity and structural transition in Nb1-xB2.Comment: 16 pages, 4 figure

Influence of charge status on the stress safety properties of Li(Ni₁⁄₃Co₁⁄₃Mn₁⁄₃)O₂ cells

In order to improve safety management, the stress changes of Li(Ni1/3Co1/3Mn1/3)O2 (NMC) cells are real-time monitored using non-destructive strain gauges, and the effects of gauge substrate, temperature and state-of-charge (SOC) have been investigated. The shell exhibits elastic deformation behaviour, and the strain-stress relationship is established. As the temperature increases from 25 to 80 °C, the stress of the NMC cells increases from 0 to 275 MPa, especially greatly at 70 °C and sharply at 80 °C after 18 h. The stress increases from 0 to 9.2 MPa when the potential increases from 2.8 to 4.3 V. However, the value rises from 10 to 55 MPa when the voltage increases from 4.6 to 5.0 V during the over-charge process. An obvious increase of stress appears when the cut-off voltage is below 0.6 V during over-discharge tests. The facile method is significant for non-destructive inspection and emergency management of batteries

Comparative study of the primary healthcare systems in China and Mali

Background: Community health centres (CHCs) are an important component of the health system in Mali and China. Despite patient support and commitment from the authorities, the management and the quality of care of these structures need to be improved. This research aimed to compare the management style of the relevant boards with users’ satisfaction pertaining to CHC services in Mali and China. Method: Between September 2009-January 2010, a study was conducted in eight CHCs in Mali and in 16 CHCs in China. A total of 480 householders, [60 (Mali) and 320 (China)]; and 24 management committee members (Mali) and 48 management committee members (China) were interviewed. An in-depth interview technique was used on members of the management committee, while a structured interview was carried out to collect data during face-to-face contact with householders in their residences. In residences in which there were two or more households, the first willing householder was interviewed. Questions about the level of satisfaction were coded from 1-5 and ranged from “excellent” to “very bad” respectively. Results: The CHCs in China were managed by the government, whereas in Mali, they were overseen by the local population. The most satisfied people in both countries were those living in the poorest socioeconomic conditions, the elderly, and those who attended the healthcare meetings. Chinese households were more satisfied with the quality of the CHC services than those in Mali. The Chinese management boards proposed standardisation of rules and more funding, whereas those in Mali advocated that government provide more funding and human resources allocation. Conclusion: A high level of satisfaction regarding the CHC services was observed. However, users reported on deficits in the quality of care, whereas management suggested a need for greater resource allocation.Key words: primary health care system, householders’ satisfaction, management board, China, Mal

Observation of indirect ionization of W7+ in an electron-beam ion-trap plasma

In this work, visible and extreme ultraviolet spectra of W7+ are measured using the high-temperature superconducting electron-beam ion trap (EBIT) at the Shanghai EBIT Laboratory under extremely low-energy conditions (lower than the nominal electron-beam energy of 130 eV). The relevant atomic structure is calculated using the flexible atomic code package based on the relativistic configuration interaction method. The GRASP2K code, in the framework of the multiconfiguration Dirac-Hartree-Fock method, is employed as well for calculating the wavelength of the M1 transition in the ground configuration of W7+. A line from the W7+ ions is observed at a little higher electron-beam energy than the ionization potential for W4+, making this line appear to be from W5+. A hypothesis for the charge-state evolution of W7+ is proposed based on our experimental and theoretical results; that is, the occurrence of W7+ ions results from indirect ionization caused by stepwise excitation between some metastable states of lower-charge-state W ions, at the nominal electron-beam energy of 59 eV