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Background: Reversible assembly and disassembly of nanostructures has important function in controllable construction of nanodevices. There are several methods to achieve reversible assembly/disassembly, such as pH, temperature, DNA hybridization and so on. Among these methods, pH driven reversible assembly presents superiority due to its ease-of-use and no waste produced. Herein we report a novel design that use two single-stranded (ss) DNAs wrapped single walled carbon nanotubes (SWCNTs) for the pH controlled assembly of SWCNTs without generation of waste. Results: Both of the two DNAs with a same wrapping sequence of d(GT)20 and different free terminals showed a very high tendency to wrap around carbon nanotubes. The assembly was driven by the hybridization between the two free terminals of wrapped DNAs on the neighboring SWCNTs: i-motif (four-stranded C-quadruplex) and its complemental stranded G-quadruplex which would form tight tetraplexes and break the hybridization under slightly acidic conditions. Thus the assembly and disassembly are reversibly controlled by pH. And this assembly/ disassembly process can be easily distinguished by naked eyes. Gel electrophoresis and Atomic Force Microscope are used to demonstrate the assembly and disassembly of SWCNTs at different pH. Conclusions: A novel pH induced reversible assembly and disassembly of SWCNTs was realized which may have potential applications in the area of controlled assembly of nanostructures. [ABSTRACT FROM AUTHOR]

Heterogeneous palladium catalysts have been supported on the ordered mesoporous carbons (Pd/OMC) with bimodal pores which are prepared by the surfactant-templating approach. Characterization using XRD, TEM, XPS, H2 chemisorption, and N2 sorption techniques reveals that the Pd/OMC catalysts have the ordered 2-D hexagonal mesostructure (space group of p6 mm), extremely high surface areas (~1800 m2/g), large pore volumes (~1.64 cm3/g), bimodal pores (6.3 nm of primary mesopores and 1.7 nm of secondary mesopores inside the pore walls), hydrophobic carbon surface, and small metal particles well-dispersed inside the secondary small mesopores. This catalyst exhibits a high yield of 43% for biphenyl from the Ullmann coupling reaction of chlorobenzene in water at 100 °C without assistance of any phase transfer catalyst and can be reused up to 10 times, providing potential opportunities for industrial applications such as coupling and hydrogenation reactions. [ABSTRACT FROM AUTHOR]

T cell functional exhaustion during chronic hepatitis B virus (HBV) infection may contribute to the failed viral clearance; however, the underlying molecular mechanisms remain largely unknown. Here we demonstrate that jumonji domain-containing protein 6 (JMJD6) is a potential regulator of T cell proliferation during chronic HBV infection. The expression of JMJD6 was reduced in T lymphocytes in chronic hepatitis B (CHB) patients, and this reduction in JMJD6 expression was associated with impaired T cell proliferation. Moreover, silencing JMJD6 expression in primary human T cells impaired T cell proliferation. We found that JMJD6 promotes T cell proliferation by suppressing the mRNA expression of CDKN3. Furthermore, we have identified platelet derived growth factor-BB (PDGF-BB) as a regulator of JMJD6 expression. PDGF-BB downregulates JMJD6 expression and inhibits the proliferation of human primary T cells. Importantly, the expression levels of JMJD6 and PDGF-BB in lymphocytes from CHB patients were correlated with the degree of liver damage and the outcome of chronic HBV infection treatment. Our results demonstrate that PDGF-BB and JMJD6 regulate T cell function during chronic HBV infection and may provide insights for the treatment strategies for CHB patients. [ABSTRACT FROM AUTHOR]

Heparanase is expressed in almost all advanced tumors, and therefore it may serve as a potential target for tumor therapy. Our previous study has shown that heparanase can serve as a potential universal tumor-associated antigen (TAA) for the immunotherapy of advanced tumors. Further study demonstrated that the HLA-A*0201-restricted Cytotoxic T lymphocytes (CTL) epitopes Hpa525 (PAFSYSFFV), Hpa277 (KMLKSFLKA) and Hpa405 (WLSLLFKKL) from human heparanase could induce a potent anti-tumor immune response in vitro. The present study was designed to investigate whether the above peptides could induce immune responses in mice. Our results demonstrated that the effectors from heparanase peptide-immunized mice could effectively lyse various tumor cells that were heparanase positive and HLA-A*0201 matched. We also found that these peptide-specific CTLs did not lyse autologous lymphocytes that had low heparanase activity. Further study revealed that Hpa525, Hpa277, and Hpa405 peptides increased the frequency of IFN-γ-producing T cells as compared to a negative peptide. These results suggest that Hpa525, Hpa277, and Hpa405 peptides are novel HLA-A*0201-restricted CTL epitopes capable of inducing heparanase-specific CTLs in mice. Because heparanase is expressed in most advanced malignant tumors, Hpa525, Hpa277, and Hpa405 peptide-based vaccines may be useful for the immunotherapy of patients with advanced tumors. [ABSTRACT FROM AUTHOR]

Here, we report a facile method for the preparation of monodisperse lanthanide-doped titania-coated silica nanoparticles. By hydrolysis of titanium alkoxide precursors in the presence of lanthanide ions, titania coatings have been deposited on the surface of the silica nanoparticles dispersed in the pure ethanol. Lanthanide ions were directly incorporated into the coating during the coating process. For a given ratio of titanium alkoxide to water, the density of the doped ions is determined by the concentration of the lanthanide ions in the reactant mixture. The final particles were nanosized, discrete, and exhibiting luminescence when excited. [ABSTRACT FROM AUTHOR]