[Show abstract][Hide abstract] ABSTRACT: The liver is a unique lymphoid organ whose microenvironment is biased towards tolerance induction. We previously found that a proportion of CD4+ autoreactive recent thymic emigrants (RTEs) retained in the liver after thymic egress and acquired IL-10 producing capability. To investigate the tolerance of these liver persisting CD4+ RTEs in more detail and to study the liver stromal cell types that facilitate the tolerogenic changes in young T cells, the phenotype and function of liver RTEs were further characterized and the impact of liver sinusoidal endothelial cells (LSECs) and Kupffer cells on RTEs were examined using an in vitro co-culture system. More than 70% of CD4+ CD44hi RTEs in the liver acquired Foxp3-LAG3+ CD49b− regulatory phenotype and function. But higher ratio of apoptosis with enhanced FasL and Bim expression was also found in these CD4+ liver RTEs when compared to those in the lymph nodes and spleen. LSECs played an important role in RTEs’ acquisition of tolerogenic and regulatory phenotype. These results indicate an important role of liver microenvironment in enforcing peripheral tolerance to CD4+ thymic emigrants against self- and gut-derived antigens.
[Show abstract][Hide abstract] ABSTRACT: Regulated necrosis (necroptosis) and apoptosis are crucially involved in severe cardiac pathological conditions, including myocardial infarction, ischemia-reperfusion injury and heart failure. Whereas apoptotic signaling is well defined, the mechanisms that underlie cardiomyocyte necroptosis remain elusive. Here we show that receptor-interacting protein 3 (RIP3) triggers myocardial necroptosis, in addition to apoptosis and inflammation, through activation of Ca(2+)-calmodulin-dependent protein kinase (CaMKII) rather than through the well-established RIP3 partners RIP1 and MLKL. In mice, RIP3 deficiency or CaMKII inhibition ameliorates myocardial necroptosis and heart failure induced by ischemia-reperfusion or by doxorubicin treatment. RIP3-induced activation of CaMKII, via phosphorylation or oxidation or both, triggers opening of the mitochondrial permeability transition pore and myocardial necroptosis. These findings identify CaMKII as a new RIP3 substrate and delineate a RIP3-CaMKII-mPTP myocardial necroptosis pathway, a promising target for the treatment of ischemia- and oxidative stress-induced myocardial damage and heart failure.
[Show abstract][Hide abstract] ABSTRACT: The development of visible-light-responsive photocatalysts is a promising challenge in the disinfectant of environmental pollution. Silver-silver halides nano-photocatalysts have received intensive attention due to their excellent photocatacatalytic performance in recent years, where silver nanoparticles/nanoclusters demonstrate plasmonic enhanced light absorption efficiency and have been considered as an important component in various functional photocatalytic nanocomposite materials, serving for harvesting visible light. This review provides an overall survey on the state-of-the-art silver-silver halides-based photocatalysts, fundamental understanding of their plasmonically induced photo-reactions and their major environmental applications. We first discuss the basic concepts of localized surface plasmon resonance, and outline general mechanism of silver-silver halides-based photocatalysis. We then discuss the latest progress in the design and fabrication of silver halide based photocatalysis using various strategies. Next, we highlight some selected examples to demonstrate the new applications of silver/silver halides nano-photocatalysts. Eventually, we provide an outlook of the present challenges and some perspectives of new directions in this interesting and emerging research area.
No preview · Article · Dec 2015 · Journal of Materials Chemistry A
[Show abstract][Hide abstract] ABSTRACT: Carrier localization effect has been observed in GaN/AlGaN multiquantum wells (MQWs) by analyzing the temperature dependent photoluminescence (PL) results. Specifically, two neighbouring peaks can be seen in the PL spectra with an abnormal variation when increasing the temperature. A conduction band model with two minimal potentials corresponding to two carrier localizations is proposed to explain the PL spectra.
[Show abstract][Hide abstract] ABSTRACT: Quasi-one-dimensional gold grating with Si3N4 cap layer has been studied to enhance the optical coupling of AlGaN/GaN quantum well infrared photodetector (QWIP) by finite element method (FEM). The averaged |Ez|2 across the whole quantum well region reaches 1.49 (V/m)2 when the electric field intensity (|E0|2) of normal incidence is 1 (V/m)2 at 4.6 μm, showing 1.9 times increase compared with that obtained via bare gold grating. The results show that Si3N4 cap layer plays an indispensable role in inducing the electric field component Ez perpendicular to multi-quantum wells (MQWs) via not only decreasing the Fresnel reflection but also exciting stronger plasmonic resonance on the upper surface of the quasi-one-dimensional gold grating.
[Show abstract][Hide abstract] ABSTRACT: Multiple reaction monitoring (MRM) is a universal approach for quantitative analysis because of its high specificity and sensitivity. Nevertheless, optimization of MRM parameters remains as a time and labor-intensive task particularly in multiplexed quantitative analysis of small molecules in complex mixtures. In this study, we have developed an approach named Stepped MSAll Relied Transition (SMART) to predict the optimal MRM parameters of small molecules. SMART requires firstly a rapid and high-throughput analysis of samples using a Stepped MSAll technique (sMSAll) on a Q-TOF, which consists of serial MSAll events acquired from low CE to gradually stepped-up CE values in a cycle. The optimal CE values can then be determined by comparing the extracted ion chromatograms for the ion pairs of interest among serial scans. The SMART-predicted parameters were found to agree well with the parameters optimized on a triple quadrupole from the same vendor using a mixture of standards. The parameters optimized on a triple quadrupole from a different vendor was also employed for comparison, and found to be linearly correlated with the SMART-predicted parameters, suggesting the potential applications of the SMART approach among different instrumental platforms. This approach was further validated by applying to simultaneous quantification of 31 herbal components in the plasma of rats treated with a herbal prescription. Because the sMSAll acquisition can be accomplished in a single run for multiple components independent of standards, the SMART approach are expected to find its wide application in the multiplexed quantitative analysis of complex mixtures.
No preview · Article · Dec 2015 · Analytica chimica acta
[Show abstract][Hide abstract] ABSTRACT: Calcitriol (1α,25-dihydroxyvitamin D3) has demonstrated anticancer activity against several tumors. However, the underlying mechanism for this activity is not yet fully understood. Our experiment was designed and performed to address one aspect of this issue in cervical cancer. HeLa S3 cells were cultured in media with various concentrations of calcitriol. Cell proliferation and cell cycle were assessed by spectrophotometry and flow cytometry, respectively. The mRNA and protein expression levels of human cervical cancer oncogene (HCCR-1) and p21 were determined by RT-PCR and Western blot, respectively. Results indicated that calcitriol inhibited HeLa S3 cell proliferation and induced cell cycle arrest at the G1 phase. Calcitriol decreased HCCR-1 protein expression in a dose- and time-dependent manner. Furthermore, promoter activity analyses revealed that transcriptional regulation was involved in the inhibition of HCCR-1 expression. Overexpression of HCCR-1 in HeLa S3 cells reversed the inhibition of cell proliferation and G1 phase arrest that resulted from calcitriol treatment. In addition, calcitriol increased p21 expression and promoter activity. HCCR-1 overexpression decreased p21 expression and promoter activity. Thus, our results suggested that calcitriol inhibited HeLa S3 cell proliferation by decreasing HCCR-1 expression and increasing p21 expression.
No preview · Article · Nov 2015 · Oncology Research Featuring Preclinical and Clinical Cancer Therapeutics
[Show abstract][Hide abstract] ABSTRACT: The exciton localization effect in nonpolar a-plane GaN/AlGaN multiquantum wells (MQWs) structures with different quantum confinements (different well thicknesses or Al molar fractions of barrier) has been investigated by temperature dependent photoluminescence (PL). An "S-shaped" PL peak energy variation is observed in the spectra, indicating the existence of localized states. The exciton localization energy is larger in the MQWs with stronger quantum confinement. A good agreement of the localization energy is obtained by theoretical calculation assuming ± 5% fluctuation of well thickness, which demonstrates that potential minima caused by well thickness fluctuation are the major origin of exciton localization. In addition, the internal quantum efficiency shows more than 3 times enhancement with decreasing the well width from 8.1 to 2.7 nm due to the strong exciton localization which can prevent the carriers from trapping into the nonradiative recombination centers.
No preview · Article · Nov 2015 · Optical Materials Express
[Show abstract][Hide abstract] ABSTRACT: Metal/semiconductor nanostructure materials have been used as surface-enhanced Raman scattering (SERS) active substrates and have drawn much attention due to their widespread applications in both optical and electronics fields. Here, we report a simple approach to prepare a large-scale ZnO/SiO2/Ag nanoparticles (NPs) by the reduction of [Ag(NH3)2]+ with the reducing agent SnCl2·H2O in aqueous solution on the surface of activated ZnO/SiO2 microspheres. The thin SiO2 layer inserted between the ZnO and Ag has been demonstrated to be able to passivate the surface states of ZnO and improve the dispersion of Ag on the surface of NPs, thus enhanced the scattering intensity. The fabricated hybrids are found to be effective SERS substrates because of their homogeneous morphology and the ability to create a strong polarization induced local electromagnetic field by the metal–semiconductor heterojunction.
No preview · Article · Nov 2015 · Materials Letters
[Show abstract][Hide abstract] ABSTRACT: The assembly of nanocrystals into ordered structures called supercrystals or superstructures has become a pivotal frontier owing to numerous useful applications such as correlating the arrangements of atoms in macroscopic crystals and tuning the collective properties to meet the demands of various applications. In this article, recent progress in the preparation of three-dimensional superlattices of nanocrystals is outlined, with a particular emphasis on the driving forces and evolutionary routes beyond orderly assembly. First, the leading or repulsive forces that internally and externally govern the formation of three-dimensional supercrystals are systematically identified and discussed with respect to their origins and functions in three-dimensional self-organization. Then a synoptic introduction of commonly applied means of nanocrystal self-assembly based on growth scenarios such as droplet evaporation and a liquid/liquid interface is presented with specific cases and detailed analyses. Finally, the existing challenges and prospects for this field are briefly highlighted.
[Show abstract][Hide abstract] ABSTRACT: Pt nanoparticles (NPs) have been immobilized on the support of nanoscale zeolitic imidazolate framework (ZIF-8) and graphene oxide (GO) via a facile liquid impregnation method, in which H2PtCl6, NaBH4 and polyvinyl alcohol (PVA) act as the Pt precursor, reducing and stabilizing agents, respectively. The resulting Pt@ZIF-8/GO composite was characterized by powder X-ray diffraction, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, inductively coupled plasma emission spectroscopy, energy dispersive spectroscopy and N2 adsorption-desorption analysis. The results showed that Pt metal catalysts with an average size of 3.8 nm were highly dispersed and anchored tightly on the external surface of the ZIF-8/GO support. The hydrogen storage performance of Pt@ZIF-8/GO was investigated. The hydrogen storage capacity of Pt@ZIF-8/GO at 298 K and 10.0 bar is 2.2 times higher than that of the parent ZIF-8. The enhanced hydrogen storage capacity is mainly attributed to the hydrogen spillover mechanism involved in such catalytic systems. The high dispersion and small size of Pt NPs, as well as intimate contacts between the Pt dissociation source and ZIF-8/GO receptor are crucial to achieving such an obvious increase in room-temperature hydrogen storage capacity.
No preview · Article · Aug 2015 · International Journal of Hydrogen Energy
[Show abstract][Hide abstract] ABSTRACT: Mesoscopic WO3 microspheres composed of self-assembly nanofibers were prepared by hydrothermal reaction of tungsten acid potassium and H2O2. The mesoscopic WO3 microspheres offer desired porous properties and large effective active areas provided by intertwining nanofibers, thereby resulting in excellent supercapacitive properties due to facile electrolyte flow and fast reaction kinetics. In three electrode configuration, mesoscopic WO3 microspheres exhibit specific capacitance value of 797.05 F g−1 at the current density of 0.5 A g−1 and excellent cycling stability without decay after 2000 cycles in 2 M H2SO4 aqueous solution. These values are superior to other reported WO3 composites. An asymmetric supercapacitor is constructed using the as-prepared WO3 mesoscopic microspheres as the positive electrode and the activated carbon as the negative electrode, which displays excellent electrochemical performance with a maximum energy density of 97.61 Wh kg−1 and power density of 28.01 kW kg−1. These impressive performances suggest that the mesoscopic WO3 microspheres are promising electrode materials for supercapacitor.
No preview · Article · Aug 2015 · Electrochimica Acta
[Show abstract][Hide abstract] ABSTRACT: High-efficient chemical sensors based on various nanostructures have attracted considerable attention owing to their practical applications in industry and in daily lives of human beings. One of the most interesting and urgent challenges is to synthesize hierarchical heterostructured nanomaterials with high performance. In this paper, hierarchical p-n junction nanostructures made of n-type SnO2 nanosheets standing on p-type carbon nanofibers have been successfully fabricated by combining electrospinning technique and hydrothermal method. The morphologies of the SnO2 nanosheets can be easily controlled through tuning experimental conditions such as hydrothermal reaction time. The gas sensing performances based on the hierarchical nanostructures with hydrogen as target molecules have been evaluated. The expected sensing performances (e.g., low operating temperature, large response and fast response-recovery behaviors) have been achieved owing to the synergy effect between SnO2 nanosheets, CNFs and the well-defined shaped hybrid nanostructures.
[Show abstract][Hide abstract] ABSTRACT: Interleukin-30 (IL-30), or IL-27p28, is the α subunit of IL-27 constructed by Epstein-Barr virus induced gene 3 (EBI3) and IL-27p28 binding via non-covalent bonds. IL-30 can be independently secreted and function independent of IL-27. Recent studies demonstrated IL-30 could concurrently antagonize T helper 1 (Th1) and Th17 responses and might have therapeutic implications for controlling autoimmune diseases. However no reports have stated an efficient method to generate relatively large quantity of IL-30. In the present study, anE.coli expression system for the rapid expression of the mouse IL-30 is developed. For the first time, IL-30 was expressed in a form of soluble fusion protein and purified using a way of simple affinity chromatography. In order to avoid the impact of minor codons on expressing eukaryotic protein in E.coli and improve the expression quantity, the nucleotide sequence of IL-30 was optimized. The optimized gene sequence was then sub-cloned into the pET-44a (+) vector, which allowed expression of IL-30 with a fusion tag - NusA. The vector was transformed into E.coli and the expressed fusion protein, NusA-IL-30, was purified by Ni-chromatography. Then the fusion tag was removed by cleavage with thrombin. The purify of purified IL-30 was identified using SDS-PAGE as well as HPLC and the purify was up to about 92%. And the yield of IL-30 was 8.95 mg from 1 L of bacterial culture. Western blot confirmed the identity of the purified protein. The recombinant IL-30 showed its biological activity by inhibiting Th17 differentiating from Naïve CD4(+) T cells. Therefore, this method of express and purify IL-30 provide novel procedures to facilitate structural and functions studies of IL-30.
[Show abstract][Hide abstract] ABSTRACT: To seek robust active photocatalysts for sunlight-driven water splitting, a variety of semiconductor materials have been developed to achieve high photocatalytic efficiency. In this work, the CdS nanoplates with rough surface have been synthesized through a two-step ionic-exchange route. The as-synthesized sample was modified by Pt in an in situ photo-deposition cell to fabricate hybrid Pt/CdS nanophotocatalyst. The rate of average solar hydrogen evolution over the Pt/CdS nanoplates reached 3.75mmolh-1g-1, which is significantly higher than that of bare CdS and NiS/CdS counterparts. Furthermore, the Pt/CdS exhibited very high stability in continuous solar H2 evolution at a relatively stable state even over a 16-day reaction period, implying the as-fabricated hybrid nanophotocatalyst is approaching the practical requirements. The significantly enhanced photocatalytic efficiency was ascribed to the merits of rough plate-like nanostructures and the assistance of Pt co-catalyst, which can promote the light-absorption capability and photo-carrier separation as well as provide reactive sites. The present work opens an avenue to construct efficient and stable solar-driven catalysts for new energy creation.
No preview · Article · Jul 2015 · The Chemical Engineering Journal
[Show abstract][Hide abstract] ABSTRACT: We have prepared nanocomposites of well-defined spherical AgI nanostructures wrapped in reduced graphene oxide nanosheets (AgI@RGO). The as-obtained AgI@RGO nanocomposites exhibit an enhanced photocatalytic activity and stability in the degradation of organic pollutants, namely, Rhodamine B (RhB), in comparison with bare AgI nanospheres. The hybridization of AgI nanospheres with RGO nanosheets affords a good adsorptive capacity for RhB molecules, facilitated charge transfer, and suppressed recombination of electron–hole pairs. These figures of merit lead to an enhanced photocatalytic performance over AgI@RGO. This work opens new possibilities for the development of highly efficient and stable visible-light-driven composite photocatalysts for environmental purification.
[Show abstract][Hide abstract] ABSTRACT: Pregnane X receptor (PXR) activation exhibits anti-inflammatory effects via repressing nuclear factor kappa B (NF-κB); however, its over-activation may disrupt homeostasis of various enzymes and transporters. Here, we found that ginsenosides restore PXR/NF-κB signaling in the inflamed conditions without disrupting PXR function in normal conditions. The effects and mechanisms of ginsenosides in regulating PXR/NF-κB signals were determined both in vitro and in vivo. Ginsenosides significantly inhibited NF-κB activation and restored the expression of PXR target genes in TNFα-stimulated LS174T cells. Despite not PXR agonists, ginsenosides repressed NF-κB activation in a PXR-dependent manner. Ginsenosides significantly increased the physical association between PXR and NF-κB p65 subunit and thereby decreasing the nuclear translocation of p65. Ginsenoside Rb1 and compound K (CK) were found to be major bioactive compounds in the regulating PXR/NF-κB signaling. Consistently, ginsenosides significantly attenuated DSS-induced experimental colitis, which was associated with the restored PXR/NF-κB signaling. This study indicates that ginsenosides may elicit anti-inflammatory effects via targeting PXR/NF-κB interaction without disrupting PXR function in healthy conditions. Ginsenoside Rb1 and CK may serve as leading compounds in the discovery of new drugs targeting PXR/NF-κB interaction for IBD therapy.
The American Society for Pharmacology and Experimental Therapeutics.
No preview · Article · May 2015 · Drug metabolism and disposition: the biological fate of chemicals
[Show abstract][Hide abstract] ABSTRACT: The synthesis of noble metal nanocrystals terminated with high-index facets has received increasing attention due to the remarkable improvement on their catalytic performance. Introducing a transition metal to the noble metal could result in a reduced cost and potentially improved properties. By keeping in mind both of the advantages, we have developed a new synthetic approach to fabricate size-controlled Pt3Fe concave nanocubes using a high-temperature organic solution system containing oleylamine and oleic acid. It was further demonstrated that the particle size and concavity could be controlled by a number of parameters such as ratio of oleylamine and oleic acid, physic-chemical properties of metal carbonyl, metal valence in the precursor and ratio of metal precursors. Catalytic tests show that the high-index-surface-terminated Pt3Fe concave nanocubes exhibit superior performance in both hydrogenation of styrene and reduction of 4-nitrophenol in comparison with their counterparts.