Sichuan University

About: Sichuan University is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Population & Catalysis. The organization has 107623 authors who have published 102844 publications receiving 1612131 citations. The organization is also known as: Sìchuān Dàxué.

Ultrasonic irradiation: A novel approach to prepare conductive polyaniline/nanocrystalline titanium oxide composites

Abstract: A novel approach, i.e., ultrasonic irradiation, was used to prepare polyaniline/nanocrystalline TiO2 composite particles. Polymerization of aniline proceeded under ultrasonic irradiation in the presence of nanocrystalline TiO2. The aggregation of nano TiO2 can be reduced under ultrasonic irradiation, and the nanoparticles can be redispersed in the aqueous solution. The polyaniline deposits on the surface of the nanoparticle, which leads to a core−shell structure. The resulting polyaniline/nano TiO2 composite particles are spherical, and the sizes vary with the content of TiO2. The polyaniline/nano TiO2 composite particles prepared by the conventional stirring method have a “raspberry” aggregate structure, which is different from that obtained through ultrasonic irradiation. The presence of nanocrystalline TiO2 strengthens the UV absorption of polyaniline and leads to a blue shift of the π-polaron absorption of polyaniline. Ultrasound can enhance the doping level. When polyaniline deposits on the surface o...

Guidelines for the use of flow cytometry and cell sorting in immunological studies

Abstract: The marriage between immunology and cytometry is one of the most stable and productive in the recent history of science. A rapid search in PubMed shows that, as of July 2017, using “flow cytometry immunology” as a search term yields more than 68 000 articles, the first of which, interestingly, is not about lymphocytes. It might be stated that, after a short engagement, the exchange of the wedding rings between immunology and cytometry officially occurred when the idea to link fluorochromes to monoclonal antibodies came about. After this, recognizing different types of cells became relatively easy and feasible not only by using a simple fluorescence microscope, but also by a complex and sometimes esoteric instrument, the flow cytometer that is able to count hundreds of cells in a single second, and can provide repetitive results in a tireless manner. Given this, the possibility to analyse immune phenotypes in a variety of clinical conditions has changed the use of the flow cytometer, which was incidentally invented in the late 1960s to measure cellular DNA by using intercalating dyes, such as ethidium bromide. The epidemics of HIV/AIDS in the 1980s then gave a dramatic impulse to the technology of counting specific cells, since it became clear that the quantification of the number of peripheral blood CD4+ T cells was crucial to follow the course of the infection, and eventually for monitoring the therapy. As a consequence, the development of flow cytometers that had to be easy-to-use in all clinical laboratories helped to widely disseminate this technology. Nowadays, it is rare to find an immunological paper or read a conference abstract in which the authors did not use flow cytometry as the main tool to dissect the immune system and identify its fine and complex functions. Of note, recent developments have created the sophisticated technology of mass cytometry, which is able to simultaneously identify dozens of molecules at the single cell level and allows us to better understand the complexity and beauty of the immune system.

Rapid microwave-assisted green synthesis of 3D hierarchical flower-shaped NiCo₂O₄ microsphere for high-performance supercapacitor.

Abstract: Binary metal oxides with three-dimensional (3D) superstructure have been regarded as desirable electrode materials for the supercapacitor due to the combination of the improved electrical conductivity and effective porous structure. 3D hierarchical flower-shaped nickel cobaltite (NiCo2O4) microspheres have been fabricated by a rapid and template-free microwave-assisted heating (MAH) reflux approach followed by pyrolysis of the as-prepared precursors. The flower-shaped NiCo2O4 microspheres, composed of ultrathin nanopetals with thickness of about 15 nm, are endowed with large specific surface area (148.5 m(2) g(-1)) and a narrow pore size distribution (5-10 nm). The as-fabricated porous flower-shaped NiCo2O4 microspheres as electrode materials for supercapacitor exhibited high specific capacitance of 1006 F g(-1) at 1 A g(-1), enhanced rate capability, and excellent electrochemical stability with 93.2% retention after 1000 continuous charge-discharge (CD) cycles even at a high current density of 8 A g(-1). The desirable integrated performance enables it to be a promising electrode material for the electrochemical supercapacitor (EC).

Uptake, distribution, clearance, and toxicity of iron oxide nanoparticles with different sizes and coatings

Abstract: Iron oxide nanoparticles (IONPs) have been increasingly used in biomedical applications, but the comprehensive understanding of their interactions with biological systems is relatively limited. In this study, we systematically investigated the in vitro cell uptake, cytotoxicity, in vivo distribution, clearance and toxicity of commercially available and well-characterized IONPs with different sizes and coatings. Polyethylenimine (PEI)-coated IONPs exhibited significantly higher uptake than PEGylated ones in both macrophages and cancer cells, and caused severe cytotoxicity through multiple mechanisms such as ROS production and apoptosis. 10 nm PEGylated IONPs showed higher cellular uptake than 30 nm ones, and were slightly cytotoxic only at high concentrations. Interestingly, PEGylated IONPs but not PEI-coated IONPs were able to induce autophagy, which may play a protective role against the cytotoxicity of IONPs. Biodistribution studies demonstrated that all the IONPs tended to distribute in the liver and spleen, and the biodegradation and clearance of PEGylated IONPs in these tissues were relatively slow (>2 weeks). Among them, 10 nm PEGylated IONPs achieved the highest tumor uptake. No obvious toxicity was found for PEGylated IONPs in BALB/c mice, whereas PEI-coated IONPs exhibited dose-dependent lethal toxicity. Therefore, it is crucial to consider the size and coating properties of IONPs in their applications.