A hydrothermal method was developed to grow ultrathin MoS2 nanosheets, with an expanded spacing of the (002) planes, on carbon nanotubes. When used as a sodium-ion battery anode, the composite exhibited a specific capacity of 495.9 mAh g(-1), and 84.8% of the initial capacity was retained after 80 cycles, even at a current density of 200 mA g(-1). X-ray diffraction analyses show that the sodiation/desodiation mechanismis based on a conversion reaction. The high capacity and long-term stability at a high current ate demonstrate that the composite is a very promising candidate for use as an anode material in sodium-ion batteries.
Electrical excitability, which plays an important role in excitation-contraction coupling in the pulmonary vasculature, is regulated by transmembrane ion flux in pulmonary artery smooth muscle cells (PASMC). This study examined the heterogeneous nature of native voltage-dependent K(+) channels in human PASMC. Both voltage-gated K(+) (K(V)) currents and Ca(2+)-activated K(+) (K(Ca)) currents were observed and characterized. In cell-attached patches of PASMC bathed in Ca(2+)-containing solutions, depolarization elicited a wide range of K(+) unitary conductances (6-290 pS). When cells were dialyzed with Ca(2+)-free and K(+)-containing solutions, depolarization elicited four components of K(V) currents in PASMC based on the kinetics of current activation and inactivation. Using RT-PCR, we detected transcripts of 1) 22 K(V) channel alpha-subunits (K(V)1.1-1.7, K(V)1.10, K(V)2.1, K(V)3.1, K(V)3.3-3.4, K(V)4.1-4.2, K(V)5.1, K(V) 6.1-6.3, K(V)9.1, K(V)9.3, K(V)10.1, and K(V)11.1), 2) three K(V) channel beta-subunits (K(V)beta 1-3), 3) four K(Ca) channel alpha-subunits (Slo-alpha 1 and SK2-SK4), and 4) four K(Ca) channel beta-subunits (K(Ca)beta 1-4). Our results show that human PASMC exhibit a variety of voltage-dependent K(+) currents with variable kinetics and conductances, which may result from various unique combinations of alpha- and beta-subunits forming the native channels. Functional expression of these channels plays a critical role in the regulation of membrane potential, cytoplasmic Ca(2+), and pulmonary vasomotor tone.
plays an important role in control of apoptosis and proliferation in addition to regulating membrane potential and pulmonary vascular tone. Bone morphogenetic proteins (BMPs) inhibit proliferation and induce apoptosis in normal human PASMC, whereas dysfunctional BMP signaling and downregulated KV channels are involved in pulmonary vascular medial hypertrophy associated with pulmonary hypertension. This study evaluated the effect of BMP-2 on K V channel function and expression in normal human PASMC. BMP-2 (100 nM for 18 -24 h) significantly (Ͼ2-fold) upregulated mRNA expression of KCNA5, KCNA7, KCNA10, KCNC3, KCNC4, KCNF1, KCNG3, KCNS1, and KCNS3 but downregulated (at least 2-fold) KCNAB1, KCNA2, KCNG2, and KCNV2. The most dramatic change was the Ͼ10-fold downregulation of KCNG2 and KCNV2, two electrically silent ␥-subunits that form heterotetramers with functional K V channel ␣-subunits (e.g., KCNB1-2). Furthermore, the amplitude and current density of whole cell KV currents were significantly increased in PASMC treated with BMP-2. It has been demonstrated that K ϩ currents generated by KCNB1 and KCNG1 (or KCNG2) or KCNB1 and KCNV2 heterotetramers are smaller than those generated by KCNB1 homotetramers, indicating that KCNG2 and KCNV2 (2 subunits that were markedly downregulated by BMP-2) are inhibitors of functional K V channels. These results suggest that BMP-2 divergently regulates mRNA expression of various K V channel ␣-, -, and ␥-subunits and significantly increases whole cell KV currents in human PASMC. Finally, we present evidence that attenuation of c-Myc expression by BMP-2 may be involved in BMP-2-mediated increase in K V channel activity and regulation of KV channel expression. The increased KV channel activity may be involved in the proapoptotic and/or antiproliferative effects of BMP-2 on PASMC. pulmonary arterial hypertension; patch clamp; membrane potential ACTIVITY OF VOLTAGE-GATED K ϩ (K V ) channels in vascular smooth muscle cells regulates the resting membrane potential and excitation-contraction coupling (57). The current generated by K ϩ efflux through K V channels, I K(V) , is heavily influenced by numerous vasoactive agonists that control vascular tone (57). In pulmonary arterial smooth muscle cells (PASMC) from animals and humans, downregulated K V channel expression and reduced K V channel function have been linked to pulmonary vasoconstriction triggered by acute hypoxia (33,70,79,104) and to the sustained pulmonary vasoconstriction and severe pulmonary vascular remodeling induced by chronic hypoxia (69, 81, 88). Persistent hypoxic pulmonary vasoconstriction and hypoxia-mediated pulmonary vascular medial hypertrophy increase pulmonary vascular resistance, which contributes to the development of pulmonary hypertension and subsequent right heart failure in patients with chronic obstructive pulmonary disease and congenital cardiopulmonary diseases, as well as in residents living in highaltitude areas.In addition to contribution to hypoxia-mediated pulmonary hypertension, intimal and media...
As low abundance is the great obstacle for glycoprotein analysis, the development of materials with high efficiency and selectivity for glycoprotein enrichment is a prerequisite in glycoproteome research. Herein, we report a new kind of hydrophilic boronate affinity monolith by attaching 4-mercaptophenylboronic acid (MPBA) with 2-mercaptoethylamine (MPA) on the gold nanoparticle-modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate)) monolith for glycoprotein enrichment. With poly(ethylene glycol) diacrylate as the cross-linker and the further modification of gold nanoparticles, the matrix has advantages of good hydrophilicity and enhanced surface area, which are beneficial to improve the enrichment selectivity and efficiency for glycoproteins. The attachment of MPBA and MPA provide intramolecular BN coordination, which could further enhance the specificity of glycoprotein capture. Such a boronate affinity monolith was applied to enrich horseradish peroxidase (HRP) from the mixture of HRP and bovine serum albumin (BSA), and high selectivity was obtained even at a mass ratio of 1:1000. In addition, the binding capacity of ovalbumin on such monolith reached 390 μg g(-1) . Furthermore, the average recovery of HRP on the prepared affinity monoliths was (84.8±1.9) %, obtained in three times enrichment with the same column. Finally, the boronate affinity monolith was successfully applied for the human-plasma glycoproteome analysis. As a result, 160 glycoproteins were credibly identified from 9 μg of human plasma, demonstrating the great potential of such a monolith for large-scale glycoproteome research.
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