The Role of Survivin in Podocyte Injury Induced by Puromycin Aminonucleoside

Objective

Survivin is a member of the inhibitor of apoptosis protein family, which uniquely promotes mitosis and regulates apoptosis in cancer cells. Recent studies have demonstrated that survivin also expresses in several normal adult cells. In the present study, we aimed to investigate the function of survivin in the terminally differentiated epithelial cells, podocytes.

Methods

Survivin expression and location were detected by Quantitative Real-Time PCR, western blot and fluorescence confocal microscopy methods in normal and injured mouse podocytes. Cyto-protection function of survivin was also studied in cultured podocyte injured by puromycin aminonucleoside (PAN), transfected with survivin siRNA to down-regulate survivin expression, or with survivin plasmid to transiently over-express survivin.

Results

In podocytes, PAN stimulated expressions of survivin and the apoptosis related molecule caspase 3. Knockdown of survivin expression by siRNA increased the activation of caspase 3, induced podocyte apoptosis and remarkable rearrangement of actin cytoskeleton. Moreover, over-expression of survivin inhibited PAN-induced podocyte apoptosis and cytoskeleton rearrangement.

Conclusion

Our data provides the evidence that survivin plays an important role in protecting podocytes from apoptosis induced by PAN. The mechanism of survivin related anti-apoptosis may, at least partially, be through the activation of caspase 3.     

Phase-pure iron pyrite nanocrystals for low-cost photodetectors

Earth-abundant iron pyrite (FeS₂) shows great potential as a light absorber for solar cells and photodetectors due to their high absorption coefficient (>10⁵ cm^-1). In this paper, high-quality phase-pure and single crystalline pyrite nanocrystals were synthesized via facile, low-cost, and environment friendly hydrothermal method. The molar ratio of sulphur to iron and the reaction time play a crucial role in determining the quality and morphology of FeS₂ nanocrystals. X-ray diffraction and high-resolution transmission electron microscopy confirm that phase-pure and single crystalline pyrite nanocrystals can be synthesized with high sulphur to iron molar ratio and sufficient reaction time. For the first time, a crystalline nanogap pyrite photodetector with promising photocurrent and UV-visible photoresponse has been fabricated. This work further demonstrates a facile route to synthesize high-quality FeS₂ nanomaterials and their potential in optoelectronic applications.     

Effects of amino‐functionalized carbon nanotubes on the properties of amine‐terminated butadiene–acrylonitrile rubber‐toughened epoxy resins

Amino‐functionalized multiwalled carbon nanotubes (MWCNT‐NH₂s) as nanofillers were incorporated into diglycidyl ether of bisphenol A (DGEBA) toughened with amine‐terminated butadiene–acrylonitrile (ATBN). The curing kinetics, glass‐transition temperature (T_g), thermal stability, mechanical properties, and morphology of DGEBA/ATBN/MWCNT‐NH₂ nanocomposites were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis, a universal test machine, and scanning electron microscopy. DSC dynamic kinetic studies showed that the addition of MWCNT‐NH₂s accelerated the curing reaction of the ATBN‐toughened epoxy resin. DSC results revealed that the T_g of the rubber‐toughened epoxy nanocomposites decreased nearly 10°C with 2 wt % MWCNT‐NH₂s. The thermogravimetric results show that the addition of MWCNT‐NH₂s enhanced the thermal stability of the ATBN‐toughened epoxy resin. The tensile strength, flexural strength, and flexural modulus of the DGEBA/ATBN/MWCNT‐NH₂ nanocomposites increased increasing MWCNT‐NH₂ contents, whereas the addition of the MWCNT‐NH₂s slightly decreased the elongation at break of the rubber‐toughened epoxy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40472.     

内锥面喷头熔体静电纺丝工艺参数对纤维直径的影响

提出了1种批量化制备纳米纤维的熔体微分静电纺丝新装置——内锥面纺丝喷头,并研究了纺丝过程中主要的工艺参数——电场强度、熔体温度、气流速度对纤维成型过程及直径的影响。实验结果表明:随着电场强度增大,PP纤维直径减小,但电场强度过大时,内锥面喷头周向上的射流分布不均匀;随着熔体温度升高,纤维直径减小,但熔体温度过高时,不能成纤;气流辅助有助于纤维变细,且气流速度越大,纤维越细。     

Preparation and properties of gas barrier resin/rubber nanolaminated composites

An extremely high gas barrier resin was highly oriented and uniformly distributed in a rubber matrix layer by layer by the micro‐layer coextrusion technology and a special composite laminating device. The resulting composite had excellent gas barrier properties because of its alternating multilayer structure. Experimental tire samples were prepared and tested for high‐speed, endurance, and pressure performance. The results showed that because the barrier resin was evenly dispersed in the rubber matrix, the tire inner liner made of the composite showed excellent fatigue resistance and gas barrier performance. POLYM. ENG. SCI., 55:190–195, 2015. © 2014 Society of Plastics Engineers     

Curing Behavior and Structure of Magnesium Phosphate Chemically Bonded Ceramics with Different MgO to KH2PO4 Ratios

Magnesium phosphate chemically bonded ceramics attracted much attention because of its good biocompatibility. In this work, curing behavior and microstructure of magnesium phosphate chemically bonded ceramics with different MgO to KH₂PO₄ ratios were investigated. The results showed that the setting time decreased and the maximum temperature during the solidifying process increased as the increase of MgO to KH₂PO₄ ratio. Phase compositions were different for those samples fabricated with different MgO to KH₂PO₄ ratios. KH₂PO₄, MgO, and hydrated product existed in the sample with lower MgO to KH₂PO₄ ratio because of the incomplete reaction, and numerous acicular polycrystals were found. There were only MgO and hydrated product existed with the higher MgO to KH₂PO₄ ratio. Besides, a gelatinous structure with lots of cracks was also found. Clearly, the properties of magnesium potassium phosphate chemically bonded ceramics could be controlled by changing the MgO to KH₂PO₄ ratio. It is better to fabricate magnesium phosphate chemically bonded ceramics with optimal structure and properties suitable for biomedical applications in range of MgO to KH₂PO₄ ratio from 3:1 to 4:1 in this preparating conditions.     

Synthesis and Luminescent Properties of the Li0.995−xMgxSi2−xAlxN3: Eu2+0.005 Phosphors

Li_0.995?xMg_xSi_2?xAl_xN₃: Eu²⁺_0.005 (LSN: xM) (0 ≤ x ≤ 0.04) phosphors were successfully synthesized by gas‐pressed sintering. Double substitution which is partial replacement of (LiSi)⁵⁺ with (MgAl)⁵⁺ is presented as a useful way to improve luminescence properties. With an increase in the substitution concentration, the intensity of the emission band of LSN: xM was enhanced and the peak position shows blue shift due to the decreased stokes shift. Furthermore, LSN: xM (0 ≤ x ≤ 0.04) shows narrower full width at half maximum and higher thermal stability than Li_0.995Si₂N₃: Eu²⁺_0.005.     

3D Hierarchical Bi<Subscript>2</Subscript>S<Subscript>3</Subscript> Nanostructures by Polyvinylpyrrolidone (PVP) and Chloride Ion-Assisted Synthesis and Their Photodetecting Properties

A solvothermal method has been employed to synthesize bismuth sulfide (Bi₂S₃) with three-dimensional (3D) hierarchical architectures. The influences of different types of surfactants and Cl^? species on the size and morphology were investigated. A possible formation mechanism was also proposed on the basis of time-dependent experiments. The photoresponse properties show that the conductivity of Bi₂S₃ micro-flowers is significantly enhanced and the photocurrent is approximately two orders of magnitude larger than the dark current. The response and decay times are estimated to be 142 and 151 ms, respectively. It is expected that hierarchical architectures Bi₂S₃ may provide a new pathway to develop advanced nanomaterial for high-speed and high-sensitivity photoelectrical switches and photodetecting devices.     

Gene Overexpression and RNA Silencing Tools for the Genetic Manipulation of the S-(+)-Abscisic Acid Producing Ascomycete Botrytis cinerea

The phytopathogenic ascomycete Botrytis cinerea produces several secondary metabolites that have biotechnical significance and has been particularly used for S-(+)-abscisic acid production at the industrial scale. To manipulate the expression levels of specific secondary metabolite biosynthetic genes of B. cinerea with Agrobacterium tumefaciens-mediated transformation system, two expression vectors (pCBh1 and pCBg1 with different selection markers) and one RNA silencing vector, pCBSilent1, were developed with the In-Fusion assembly method. Both expression vectors were highly effective in constitutively expressing eGFP, and pCBSilent1 effectively silenced the eGFP gene in B. cinerea. Bcaba4, a gene suggested to participate in ABA biosynthesis in B. cinerea, was then targeted for gene overexpression and RNA silencing with these reverse genetic tools. The overexpression of bcaba4 dramatically induced ABA formation in the B. cinerea wild type strain Bc-6, and the gene silencing of bcaba4 significantly reduced ABA-production in an ABA-producing B. cinerea strain.