Innovative solvent-free compound-direct synthesis of defect-rich ultra-thin NiS nanosheets for high-performance supercapacitors.

Defect engineering in NiS nanosheets is an effective method to improve their surface properties and electronic structure for promoting electrochemical properties. However, a tunable, simple, and safe strategy for the introduction of abundant defect sites with a high activity into NiS with a special microstructure is worth developing. Herein, a novel hierarchical micro-flower-like NiS using graphene-like ultra-thin nanosheets with abundant defects as the building blocks was facilely synthesized by an innovative solvent-free compound-direct reaction strategy, which employed cost-efficient NaCl as the friction agent and dispersant to ensure adequate contact between sulfur ions and nickel ions and regulate the growth direction of NiS. Graphene-like ultra-thin NiS nanosheets effectively shorten the transport distance of ions and electrons. Defect engineering in NiS nanosheets provides more adsorption and storage sites for ions and high-activity sites for electrode materials, as well as adjusts the local electronic structure so as to effectively promote ion diffusion and charge transfer. The high performance of the as-obtained N-NiS electrode is illustrated by fabricating an asymmetric supercapacitor, which exhibits a specific capacitance of 351.5 F g-1 and energy density of 71.0 W h kg-1 at a power density of 229.3 W kg-1. The solvent-free compound-direct reaction strategy demonstrated in this study provides a new direction for the synthesis of high-performance nanomaterials for electrochemical energy storage applications.

NiS2 nanoparticles by the NaCl-assisted less-liquid reaction system for the magnesium-ion battery cathode.

Rechargeable magnesium batteries are expected to be the next generation of energy storage devices. Therefore, it is of great significance to develop low-cost and long-life magnesium (Mg) electrode materials. However, the traditional method of synthesizing electrode materials is complicated, and it is difficult to remove potentially dangerous impurities. In this study, without adding any additional solvent, the crystal water in the reactant provides a liquid environment directly for the reaction, such that the whole reaction could be carried out safely and efficiently in the less liquid reaction system. Furthermore, NiS2 in the cotton-like form was synthesized under the spatial effect of NaCl solution in a confined space. The fabricated material was tightly connected and has abundant active sites, which promote the rapid transport of charge. This work provides a general strategy of preparation methods for metal sulfides and also points in a new direction for the improvement of electrochemical performance with less-liquid reaction systems without additional solvents.

Distributed Optimal Attitude Synchronization Control of Multiple QUAVs via Adaptive Dynamic Programming.

This article proposes a distributed optimal attitude synchronization control strategy for multiple quadrotor unmanned aerial vehicles (QUAVs) through the adaptive dynamic programming (ADP) algorithm. The attitude systems of QUAVs are modeled as affine nominal systems subject to parameter uncertainties and external disturbances. Considering attitude constraints in complex flying environments, a one-to-one mapping technique is utilized to transform the constrained systems into equivalent unconstrained systems. An improved nonquadratic cost function is constructed for each QUAV, which reflects the requirements of robustness and the constraints of control input simultaneously. To overcome the issue that the persistence of excitation (PE) condition is difficult to meet, a novel tuning rule of critic neural network (NN) weights is developed via the concurrent learning (CL) technique. In terms of the Lyapunov stability theorem, the stability of the closed-loop system and the convergence of critic NN weights are proved. Finally, simulation results on multiple QUAVs show the effectiveness of the proposed control strategy.

Construction of a T7 phage display nanobody library for bio-panning and identification of chicken dendritic cell-specific binding nanobodies.

Dendritic cells (DCs) are the antigen-presenting cells that initiate and direct adaptive immune responses, and thus are critically important in vaccine design. Although DC-targeting vaccines have attracted attention, relevant studies on chicken are rare. A high diversity T7 phage display nanobody library was constructed for bio-panning of intact chicken bone marrow DCs to find DC-specific binding nanobodies. After three rounds of screening, 46 unique sequence phage clones were identified from 125 randomly selected phage clones. Several DC-binding phage clones were selected using the specificity assay. Phage-54, -74, -16 and -121 bound not only with chicken DCs, but also with duck and goose DCs. In vitro, confocal microscopy observation demonstrated that phage-54 and phage-74 efficiently adsorbed onto DCs within 15 min compared to T7-wt. The pull-down assay, however, did not detect any of the previously reported proteins for chicken DCs that could have interacted with the nanobodies displayed on phage-54 and phage-74. Nonetheless, Specified pathogen-free chickens immunized with phage-54 and phage-74 displayed higher levels of anti-p10 antibody than the T7-wt, indicating enhanced antibody production by nanobody mediated-DC targeting. Therefore, this study identified two avian (chicken, duck and goose) DC-specific binding nanobodies, which may be used for the development of DC-targeting vaccines.

Evaluation of dendritic cell-targeting T7 phages as a vehicle to deliver avian influenza virus H5 DNA vaccine in SPF chickens.

Introduction: There is a growing demand for effective technologies for the delivery of antigen to antigen-presenting cells (APCs) and their immune-activation for the success of DNA vaccines. Therefore, dendritic cell (DC)-targeting T7 phages were used as a vehicle to deliver DNA vaccine. Methods: In this study, a eukaryotic expression plasmid pEGFP-C1-HA2-AS containing the HA2 gene derived from the avian H5N1 virus and an anchor sequence (AS) gene required for the T7 phage packaging process was developed. To verify the feasibility of phage delivery, the plasmid encapsulated in DC-targeting phage capsid through the recognition of AS was evaluated both in vitro and in vivo. The pEGFP-C1-HA2-AS plasmid could evade digestion by DNase I by becoming encapsulated into the phage particles and efficiently expressed the HA2 antigen in DCs with the benefit of DC-targeting phages. Results: For chickens immunized with the DC-targeting phage 74 delivered DNA vaccine, the levels of IgY and IgA antibodies, the concentration of IFN-γ and IL-12 cytokines in serum, the proliferation of lymphocytes, and the percentage of CD4+/CD8+ T lymphocytes isolated from peripheral blood were significantly higher than chickens which were immunized with DNA vaccine that was delivered by non-DC-targeting phage or placebo (p<0.05). Phage 74 delivered one-fiftieth the amount of pEGFP-C1-HA2-AS plasmid compared to Lipofectin, however, a comparable humoral and cellular immune response was achieved. Although, the HA2 DNA vaccine delivered by the DC-targeting phage induced enhanced immune responses, the protection rate of virus challenge was not evaluated. Conclusion: This study provides a strategy for development of a novel avian influenza DNA vaccine and demonstrates the potential of DC-targeting phage as a DNA vaccine delivery vehicle.

[Genetic analysis of HAV strains isolated from patients with acute hepatitis in Hebei Shijiazhuang of China].

OBJECTIVE: To characterize the hepatitis A virus (HAV) wild type strains circulating in Hebei Shijiazhuang of China during 2005-2007, to provide the bases for further investigation of the sources of HAV infection. METHODS: The VP1/P2A junction regions were detected by RT-PCR from HAV IgM positives serum samples during 2005 and 2007, the 34 RT-PCR positive samples were sequenced and subjected to phylogenetic analysis by Neighbor Joining (NJ) method. RESULTS: All the detected HAV strains were identified as sub-genotype I A, the homology of nucleotide sequence in the VP1-2A imation region ranged from 95%-100%, the amino acid sequences of HAV strains almost had no difference. CONCLUSION: There are different HAV strains existing in Hebei Shijiazhuang of China, same HAV strain may exist in different areas; or in one area, identical or different HAV strains may be detected. This work provides the bases for further investigation of the sources of HAV infection and also for effectively control measures to prevent the spread of the disease.

[Development of an extraction and concentration method for the detection of hepatitis A virus in different samples].

OBJECTIVE: To develop an extraction and concentration method for the detection of hepatitis A virus (HAV) in shellfish, water, serum and saliva samples by nested RT-PCR. METHODS: HAV were artificially inoculated into the above samples, calm sample was extracted using glycine buffer pH9.5, PEG precipitation; water sample was PEG precipitated directly; then all the samples including serum and saliva samples were extracted using Trizol regent, followed by nested RT-PCR detection using primers from HAV VP1-2A region. RESULTS: The detection limit for HAV in cultured cell lysis was 0.1TCID50; in water, serum or salva sample was 1TCID50 respectively, in calm sample was 1-10 TCID50. HAV RNA was detected in water and sera samples collected from the HAV outbreak region, sequenced and analysis. CONCLUSION: The method developed here is convenient, specific and capable of detecting low levels of HAV in different samples, would be useful for diagnostic laboratories in order to perform HAV analysis in cases of foodborne infections or for molecular epidemiology investigation of HAV outbreaks.

[In vitro study of oral Candida albicans in virulence from HIV-positive individuals].

OBJECTIVE: To study the influence of Candida albicans on human immunodeficiency virus (HIV)-positive individuals susceptible to oral candidiasis. METHODS: In vitro secreted aspartyl proteinase activities, adhesion to healthy buccal epithelial cells of Candida albicans isolates from oral cavities of subjects with and without HIV infection were measured. RESULTS: The pathogenetic isolates of Candida albicans from HIV-positive patients were significantly lower than that from HIV-negative subjects (P < 0.01) in secreted aspartyl proteinase activities and adhesion to buccal epithelial cells. There was no difference in commensals between these two groups. In the HIV-positive group, no difference was found between the pathogenetics and the commensals. However, in the HIV-negative group, the virulence of the pathogen was significantly higher than the commensals (P < 0.01). CONCLUSIONS: These results indicate that oral candidiasis was not correlated with some predominant strains of Candida albicans with higher virulence in HIV-positive subjects.