Barium titanate (BTO, BaTiO3) nanofiber was prepared via electrospinning and followed annealing process. The as-spun and calcined BTO nanofibers were characterized by a scanning electron microscope (SEM). After annealing at 800 °C in air for 3 h, polycrystalline BTO nanofibers with 120-200 nm in diameter were successfully obtained. I-V characteristic curves of single BTO nanofiber were measured. The p-type semiconducting fiber shows a room-temperature conductivity of about 0.3 S/cm. In addition, the small humidity hysteresis demonstrates the application prospects of electrospun BTO nanofibers in the fabrication of a high-sensitive humidity sensor.
The aim of the present study was to analyze the possible association between microRNA-494 (miR-494) and cell proliferation in glioma cancer. Firstly, the expression of miR-494 was revealed to be upregulated in patients with glioma, compared with the normal group. Next, anti-miR-494 mimics were used to decrease the expression of miR-494 in glioma cancer cells, which subsequently induced apoptosis, and inhibited cell growth and migration. Downregulation of miR-494 expression induced phosphatase and tensin homolog (PTEN) and suppressed the protein kinase B/mechanistic target of rapamycin pathway (Akt/mTOR) pathway in glioma cancer cells. By contrast, overexpression of miR-494 by miR-494 mimics promoted cell growth and migration, and suppressed the apoptosis of glioma cancer via the Akt/mTOR pathway by PTEN expression. Furthermore, a PTEN inhibitor was used to attenuate the function of miR-494 in glioma cancer autophagy through Akt/mTOR pathway. The promotion of PTEN promoted the function of anti-miR-494 on glioma cancer cell growth through Akt/mTOR pathway. Collectively, these results demonstrate that the effect of miRNA-494 on the proliferation and migration glioma cancer cells was mediated through Akt/mTOR pathway by PTEN expression.
Este trabalho apresenta o projeto e a preparação bem sucedidos de um filme de alumina porosa anódica do tipo sanduíche (PAA/Al 2 O 3 /PAA). Utilizou-se o processo usual, em duas etapas, de anodização de ambos os lados de uma folha de alumínio. A estrutura do filme foi determinada por microscopia eletrônica de mapeamento e emissão de campo (SEM). Os resultados obtidos na microscopia SEM mostraram que as membranas PAA têm uma nano estrutura bem definida. Todos os nano buracos apresentaram-se de forma simétrica em ambos os lados da camada de barreira. O diâmetro médio do poro encontrado foi da ordem de 40 nm.A sandwich porous anodic alumina (PAA/Al 2 O 3 /PAA) film was successfully designed and fabricated using the customary two-step anodization approach on both sides of an aluminum foil. The structure of the film was determined with field emission scanning electron microscopy (SEM). The SEM shows the PAA membranes has a well-defined nanostructure. All nanoholes stand symmetrically on both sides of the barrier layer. The average pore diameter reaches 40 nm. Keywords: porous alumina membrane, anodization, template IntroductionThe structure of porous anodic alumina (PAA) has been known as early as 1932 1 and it consists of an array of uniformly sized straight and parallel pores. Under appropriate anodic oxidation conditions, very regular self-ordered, honeycomb-like hexagonal arrays with a circular pore at the center of each hexagon can be obtained.2 The pore diameters are tunable in the range of 4 to several hundred nanometers, making PAA an ideal template for creating arrays of nanostructrured materials.3 It has been explored as template growth of metallic nanowires, 4-11 semiconductor nanowires, 12-15 magnetic nanowires 16 or carbon nanotube. 17,18However, all the above mentioned PAA membranes have only been formed on one side of the aluminum foil; the other side of the aluminum foil had to be removed. In contrast, if both sides of the aluminum foil are anodically oxidized to form two PAA membranes, a sandwich structure will be obtained. Peng and Chen 19 prepared a PAA/Al/PAA using two different anodic processes on each side of the aluminum foil. In this paper, the sandwich PAA/Al 2 O 3 /PAA membrane can be simply and rapidly fabricated by using the customary two-step oxidation process.Here two graphite sheets are used as counter electrodes during the fabrication of PAA films. A schematic representation of the whole procedure is shown in Figure 1. In the first step, a clean aluminum sheet is anodically oxidized to form an alumina membrane (A) at 40 V and 15°C in a solution of 0.3 mol L -1 oxalic acid. This preformed membrane is subsequently removed by a phosphocromic acid solution to form a textured pattern of concave substrate (B) for the second anodic oxidation process. After another anodic oxidation of B under the same condition as the first step, a well-ordered PAA/Al 2 O 3 /PAA membrane (C) with ordered pores is formed. The two-step process results in a more ordered pore structure in the final template. Beca...
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