Facile design and synthesis of a nickel disulfide/zeolitic imidazolate framework-67 composite material with a robust cladding structure for high-efficiency supercapacitors.

In this paper, a core-shell structure nickel disulfide and ZIF-67 composite electrode material (NiS2/ZIF-67) was synthesized by a two-step method. Firstly, spherical NiS2 was synthesized by a hydrothermal method, dispersed in methanol, then reacted and coated by adding cobalt ions and 2-methylimidazole to obtain the NiS2/ZIF-67 core-shell composite. The NiS2/ZIF-67 composite shows a high specific capacitance (1297.9 F g-1 at 1 A g-1) and excellent cycling durability (retaining 110.0% after 4000 cycles at 5 A g-1). Furthermore, the corresponding hybrid supercapacitor (NiS2/ZIF-67//AC HSC) has an energy density of 9.5 W h kg-1 at 411.1 W kg-1 (6 M KOH) and remarkable cycling stability (maintaining 133.3% after 5000 cycles). Its excellent electrochemical performance may be due to the core-shell structure and the synergistic effect between the transition metal sulfide and metal-organic framework. These results indicate that the NiS2/ZIF-67 composite as an electrode material with a core-shell structure has potential application in high-efficiency supercapacitors.

HIF-1α promotes the proliferation and migration of pulmonary arterial smooth muscle cells via activation of Cx43.

The proliferation of pulmonary artery smooth muscle cells (PASMCs) is an important cause of pulmonary vascular remodelling in hypoxia-induced pulmonary hypertension (HPH). However, its underlying mechanism has not been well elucidated. Connexin 43 (Cx43) plays crucial roles in vascular smooth muscle cell proliferation in various cardiovascular diseases. Here, the male Sprague-Dawley (SD) rats were exposed to hypoxia (10% O2 ) for 21 days to induce rat HPH model. PASMCs were treated with CoCl2 (200 µM) for 24 h to establish the HPH cell model. It was found that hypoxia up-regulated the expression of Cx43 and phosphorylation of Cx43 at Ser 368 in rat pulmonary arteries and PASMCs, and stimulated the proliferation and migration of PASMCs. HIF-1α inhibitor echinomycin attenuated the CoCl2 -induced Cx43 expression and phosphorylation of Cx43 at Ser 368 in PASMCs. The interaction between HIF-1α and Cx43 promotor was also identified using chromatin immunoprecipitation assay. Moreover, Cx43 specific blocker (37,43 Gap27) or knockdown of Cx43 efficiently alleviated the proliferation and migration of PASMCs under chemically induced hypoxia. Therefore, the results above suggest that HIF-1α, as an upstream regulator, promotes the expression of Cx43, and the HIF-1α/Cx43 axis regulates the proliferation and migration of PASMCs in HPH.

[Investigation of nascent polypropylene in-reactor alloy particles].

Heterogeneous nascent particles were observed in a pilot product of polypropylene in-reactor alloy, which was polymerized by Ziegler-Natta/Metallocene hybrid catalyst using Spheripol technology. Most of the particles in the product are translucent, and opaque particles were observed as well. The differences in morphology, composition, chain structure, thermal properties and mechanical properties between these two kinds of particles were investigated by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), polarized optical microscopy (POM), and differential scanning calorimetry (DSC) techniques. The results of FTIR, NMR and SEM indicate that different morphology of these two different particles is caused by different content of ethylene-propylene copolymers. The results of DSC and POM showed that the translucent particles has higher crystallization rate than opaque particles due to the presence of ethylene-propylene copolymers. The mechanical properties results showed that the impact resistance property of opaque particles is obviously lower than that of translucent particles, while its tensile strength and bending modulus are much higher than that of translucent particles. Based on the process of Spheripol technology, a preliminary explanation for the formation of different nascent PP in-reactor alloy particles is proposed.

Mechanical properties of nickel-titanium archwire used in the final treatment phase of Tip-Edge Plus technique: an in vitro study.

BACKGROUND: As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. METHODS: The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm (0.014-in) in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups: as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations (-25°, -19°, -13°, -7°, -1°, +5°, +11°). The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva (pH 6.8) and preserved at 37.0°C. Eight durations of incubation were tested: 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness (YS:E) and the load-deflection characteristics of unloading plateau section were obtained. RESULTS: Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups -25°, -19° and -13°, stiffness (YS:E) increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. CONCLUSIONS: In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated with the using time and amounts of deflection and it may affect treatment outcomes. As the main reason for wire deflection, canine crown angulation plays an important role in the wire performance. It may be wise to focus on the canine crown angulations and using time in clinic with Tip-Edge Plus technique and make proper adjustment to help to make sure the treatment outcomes.

[Comparative studies of casein phosphopeptide-amorphous calcium phosphate and fluoride products in inhibiting enamel demineralization].

OBJECTIVE: To evaluate casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and several fluoride products in inhibiting enamel demineralization. METHODS: Seventy healthy premolars extracted before orthodontic treatment were divided into seven groups (A: CPP-ACP; B: CPP-ACP + fluoride mouth rinses; C: fluoride mouth rinses; D: fluoride glass ionomer protection; E: fluoride resin binder; F: fluoride varnish; G: control group). There were ten samples in each group. The teeth were dipped into an artificial caries solution ten minutes at a time, then applied separately with CPP-ACP, CPP-ACP + fluoride mouth rinses, fluoride mouth rinses, fluoride glass ionomer protection, fluoride resin binder and fluoride varnish on labial enamel. The samples were dipped into an artificial saliva solution (37°C). Then all samples were examined with atomic force microscope (AFM) at the end of first, second and third monthes. RESULTS: At the end of the first month, surface roughness in group D [(114 ± 1) nm] was significantly lower than that in group G[(172 ± 9) nm]. At the end of the second month and the third month, significant difference was found in surface roughness between group G and the rest of groups (P < 0.05); between group B and the rest of groups; and between group C and groups (D, E and F). CONCLUSIONS: CPP-ACP and fluoride could both inhibit enamel demineralization in vitro. Solid fluoride (groups D, E and F) had better results than liquid fluoride (group C).

Synthesis and positive inotropic activity of N-(4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(piperazin-1-yl)acetamide derivatives.

A series of N-(4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(piperazin-1-yl)acetamide derivatives were synthesized and their positive inotropic activity was evaluated by measuring left atrium stroke volume on isolated rabbit heart preparations. Several compounds showed favorable activity compared with the standard drug, milrinone, among which N-(1-benzyl-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(4-benzylpiperazin-1-yl)acetamide 6j was found to be the most potent with the 13.2% increased stroke volume (milrinone 4.7%) at concentration of 3x10(-5) M in our in vitro study. The chronotropic effects of those compounds having inotropic effects were also evaluated in this work.