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Traditional cell-encapsulating scaffolds may elicit adverse host responses and inhomogeneity in cellular distribution. Thus, fabrication techniques for cellular self-assembly with micro-scaffold incorporation have been used recently to generate toroidal cellular modules for the bottom-up construction of vascular-like structures. The micro-scaffolds show advantage in promoting tissue formation. However, owing to the lack of annular cell micro-scaffolds, it remains a challenge to engineer micro-scale toroidal cellular modules (micro-TCMs) to fabricate microvascular-like structures. Here, magnetic alginate microfibers (MAMs) are used as scaffolding elements, where a winding strategy enables them to be formed into micro-rings as annular cell micro-scaffolds. These micro-rings were investigated for NIH/3T3 fibroblast growth as a function of surface chemistry and MAM size. Afterwards, micro-TCMs were successfully fabricated with the formation of NIH/3T3 fibroblasts and extracellular matrix layers on the three-dimensional micro-ring surfaces. Simple non-contact magnetic assembly was used to stack the micro-TCMs along a micro-pillar, after which cell fusion rapidly connected the assembled micro-TCMs into a microvascular-like structure. Endothelial cells or drugs encapsulated in the MAMs could be included in the microvascular-like structures as in vitro cellular models for vascular tissue engineering, or as miniaturization platforms for pharmaceutical drug testing in the future. Statement of Significance Magnetic alginate microfibers functioned as scaffolding elements for guiding cell growth in micro-scale toroidal cellular modules (micro-TCMs) and provided a magnetic functionality to the micro-TCMs for non-contact 3D assembly in external magnetic fields. By using the liquid/air interface, the non-contact spatial manipulation of the micro-TCMs in the liquid environment was performed with a cost-effective motorized electromagnetic needle. A new biofabrication paradigm of construct of microvascular-like structure. The micro-tubal-shaped structures allowed direct cell-to-cell contact that solved problems of cell-encapsulating scaffolds. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopic (XPS) studies revealed that the iron site on the chalcopyrite (CuFeS 2 ) surface was preferably oxidized to the Cu site when exposed to an oxidizing environment. Extensive density functional theory calculations were performed to investigate the surface structure of chalcopyrite and its reaction with both molecular oxygen (O 2 ) and water. The adsorption and dissociation of a single O 2 molecule, a single H 2 O molecule, as well as both molecules at the Fe and Cu sites on the CuFeS 2 (001) surface were studied. Consistent with our experimental observation, the Fe site was found to be preferred for the adsorption and dissociation of O 2 due to its lower energy barrier and greater exothermicity. The dissociation of H 2 O on the CuFeS 2 (001) surface by itself was found to be unfavorable both thermodynamically and kinetically. However, the surface formed upon O 2 dissociation was predicted to be much more reactive with H 2 O, which was attributed to favorable hydrogen transfer to the O site formed upon O 2 dissociation to hydrogen transfer to the S site due to the much weaker S H bond than the O H bond. [ABSTRACT FROM AUTHOR]

Rickettsia rickettsii is the causative pathogen of Rocky Mountain spotted fever (RMSF). Adr2, YbgF and OmpB are protective antigens of R. rickettsii . In this study, 90 candidate peptides were selected from these antigens based on their high-affinity binding capacity for the MHC class II molecule H2 I-A or H2 I-E using bioinformatic methods. Six peptides were determined using ELISPOT assay to be immunodominant based on the IFN-γ recall responses of CD4 + T cells from mice immunized with R. rickettsii . Six nucleotide sequences encoding the immunodominant peptides were linked in series and inserted into a plasmid for expression in Escherichia coli cells, resulting in a new, recombinant polypeptide termed GWP. After immunization and challenge, the rickettsial load or histopathological lesions in the organs of mice immunized with GWP or pooled peptides was significantly lower than that in organs of mice immunized with PBS or the individual peptide OmpB 399 . An in vitro neutralization test revealed that sera from mice immunized with GWP, OmpB 399 , or pooled peptides reduced R. rickettsii adherence to, and invasion of, vascular endothelial cells. Furthermore, significantly higher levels of IgG, IgG1, or IgG2a were detected in sera from mice immunized with GWP or pooled peptides, and significantly higher levels of IFN-γ or TNF-α secreted by CD4 + T cells from R. rickettsii -infected mice were detected after immunization with GWP. Altogether, our results indicated that polypeptides, especially GWP, could induce a Th1-type immune response against R. rickettsii infection, which might contribute to the rational design of peptide-based vaccines for RMSF. [ABSTRACT FROM AUTHOR]

Rickettsia heilongjiangensis , the causative agent of far eastern spotted fever, is an obligate intracellular gram-negative bacterium that belongs to the spotted fever group rickettsiae. To understand the evolution and pathogenesis of R. heilongjiangensis , we analyzed its genome and compared it with other rickettsial genomes available in GenBank. The R. heilongjiangensis chromosome contains 1333 genes, including 1297 protein coding genes and 36 RNA coding genes. The genome also contains 121 pseudogenes, 54 insertion sequences, and 39 tandem repeats. Sixteen genes encoding the major components of the type IV secretion systems were identified in the R. heilongjiangensis genome. In total, 37 β-barrel outer membrane proteins were predicted in the genome, eight of which have been previously confirmed to be outer membrane proteins. In addition, 266 potential virulence factor genes, seven partially deleted antibiotic resistance genes, and a genomic island were identified in the genome. The codon usage in the genome is compatible with its low GC content, and the amino acid usage shows apparent bias. A comparative genomic analysis showed that R. heilongjiangensis and R. japonica share one unique fragment that may be a target sequence for a diagnostic assay. The orthologs of 37 genes of R. heilongjiangensis were found in pathogenic R. rickettsii str. Sheila Smith but not in non-pathogenic R. rickettsii str. Iowa, which may explain why R. heilongjiangensis is pathogenic. Pan-genome analysis showed that R. heilongjiangensis and 42 other rickettsiae strains share 693 core genes with a pan-genome size of 4837 genes. The pan-genome-based phylogeny showed that R. heilongjiangensis was closely related to R. japonica . [ABSTRACT FROM AUTHOR]

Highlights: [•] Adr2 is a novel protective antigen of R. rickttsii. [•] Protection offered by Adr2 is mainly dependent on antigen-specific cell-mediated immune responses. [•] Adr2 could activate CD4+ and CD8+ T cells to produce great amount of TNF-α and/or IFN-γ as well as elicit rapid increase of specific IgG2a. [•] Anti-serum against Adr2 could prevent R. rickttsii from invasion of host cells. [ABSTRACT FROM AUTHOR]

Highlights: [•] rYbgF is a new discovered protective antigen against Far-Eastern spotted fever. [•] Protective mechanism of rYbgF relies on Th1-type immune response. [•] Anti-serum against rYbgF inhibits invasion of R. heilongjiangensis into host cells. [ABSTRACT FROM AUTHOR]

Abstract: The recombinant membrane-associated proteins of Coxiella burnetii, Com1, Mip and GroEL, were used in vitro to stimulate BALB/c mouse bone marrow-derived dendritic cells (BMDCs). The antigen-activated BMDCs were transferred into naïve BALB/c mice. Seven days after challenge of C. burnetii, the bacterial loads of mice receiving BMDCs activated with Com1 or Mip, but not GroEL, were significantly lower than that of mice receiving BMDCs pulsed with TrxA (Esherichia coli thioredoxin) in a quantitative polymerase chain reaction assay. After in vitro interaction with cognate antigen-pulsed BMDCs, the percentages of CD69-positive cells and TNF-α-positive cells in CD4+ and CD8+ T cells isolated from the spleens of mice receiving Com1-, Mip-, or GroEL-pulsed BMDCs were significantly higher than that of mice receiving mock-pulsed BMDCs in flow cytometric analysis. The percentages of IFN-γ-positive cells in CD4+ and CD8+ T cells from mice receiving Com1- or Mip-pulsed BMDCs were significantly greater than that of mice receiving GroEL-pulsed BMDCs. However, the percentage of IL-4-positive cells in CD4+ T cells of mice receiving GroEL-pulsed BMDCs was obviously higher than that of mice receiving Com1- or Mip-pulsed BMDCs. Our results demonstrate that Com1 and Mip are protective antigens and strongly indicate that they favor to induce IFN-γ-producing Th1 and Tc1 cells, whereas the non-protective antigen GroEL is biased to induce a Th2 response. Therefore, Com1 and Mip are key antigens to induce a protective immune response against C. burnetii infection. [Copyright &y& Elsevier]

O 2 and H 2 O molecules coadsorption on the NiS(1 0 0) surface. Pre-adsorbed oxygen atoms provide sites for H 2 O dissociation. [Display omitted] • DFT calculations results reveal that H 2 O could not dissociate on the NiS(1 0 0) surface directly in the absence of O 2. • Oxygen dissociative adsorption on the NiS(1 0 0) surface is energetically favorable. • O 2 dissociation can significantly promote H 2 O dissociation on the NiS(1 0 0) surface by providing favorable adsorption sites. Millerite (NiS) as the source of nickel extraction, is often transformed into the corresponding metal oxide in hydrometallurgical process, which involves both oxygen and water. To elucidate the oxidation mechanism, periodic density functional theory (DFT) calculations were performed to investigate the adsorption of oxygen and water on the NiS(1 0 0) surface. First, the isolated H 2 O molecule shows a relatively weak interaction with the NiS(1 0 0) surface. Furthermore, the adsorption of oxygen on the NiS(1 0 0) surface has been comprehensively discussed. The results of adsorption energies and energy barrier for oxygen dissociation show that the interaction between oxygen and the NiS(1 0 0) surface is favored thermodynamically and kinetically. Finally, it was found that the adsorbed oxygen atoms promote H 2 O dissociation significantly by diminishing the energy barrier. This work provides a microscopic insight into the oxidation mechanism of millerite in the presence of oxygen and water. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) is a deadly zoonotic pathogen that remains a burden to global health systems despite continuous vaccinations, indicating the need for an improved vaccine strategy. In this work, we constructed a new recombinant influenza vaccine using Bacillus subtilis spores expressing M2e-FP protein (RSM2eFP) and assessed its potency and efficacy in BALB/c mouse immunized via aerosolized intratracheal inoculation (i.t.) or intragastric (i.g.) administration. Immunization via i.t. route conferred 100 % protection against 20 × LD 50 A/PR/8/34 (H1N1) virus compared with only 50 % via the i.g. route. Even when challenged with 40 × LD 50 virus, the RSM2eFP vaccine immunized via i.t. provided 80 % protection. Consistently, i.t. inoculation of RSM2eFP spore vaccine induced a stronger lung mucosal immune response and a greater cellular immune response than i.g. administration, as indicated by the high production of IgG and SIgA. In addition, the RSM2eFP spore vaccine diminished the yield of infectious virus in the lung of mice immunized via i.t. These results suggest that i.t. immunization of the RSM2eFP spore vaccine may be a promising strategy for the development of mucosal vaccines against IAV infections. [ABSTRACT FROM AUTHOR]

Combining great targeting and cleaner technology is a potential strategic development in the metallurgy and materials industry. This paper proposed a nanomaterial-oriented and integrated pyrohydrometallurgy of low-grade nickel–copper (Ni–Cu) matte: temperature-programed roasting, followed by water leaching and the direct preparation of Cu@Ni–Co core–shell nanoparticles from its leachate. First, a three-step temperature-programed roasting process was designed, in which the effects of the roasting temperature scheme and NaCl additive on the water leaching rates of valuable metals were systematically investigated. Under optimized conditions, the water leaching rates of Ni, Cu, and Co were 96.8, 98.9, and 99.8%, respectively, while that of Fe was nearly zero. The leachate was a chlorine-free sulfate aqueous solution. The addition of NaCl in this study was 10% (100 mg/g), which was 5–10 times less than that in previous studies. The substantial decrease in the amount of chloride added during roasting greatly reduced the high temperature corrosion of chlorine and pollutant emission. It was confirmed that a small amount of NaCl induced the chlorination–sulfation coupling reactions of low-grade Ni–Cu matte in the appropriate roasting scheme, thereby promoting the selective sulfation of sulfides and obtaining chlorine-free roasting products. In addition, the nanopowder with the Cu@Ni–Co core–shell structure was synthesized by low-temperature hydrazine hydrate reduction from the leachate. Summarily, a novel NaCl roasting water leaching low-temperature reduction successfully realized the integration of a cleaner and efficient extraction of valuable metals and preparation of high-value nanomaterials from the low-grade Ni–Cu matte. This cleaner, material-oriented, and short process design greatly expands the industrial application of traditional mineral resources and their extractive metallurgy. • A three-step temperature-programed roasting process was designed for low-grade Ni–Cu matte. • A small amount of NaCl induced the chlorination–sulfation coupling reactions of Ni–Cu sulfides. • The water leaching rates of Ni, Cu, and Co were 96.8, 98.9, and 99.8%, respectively. • Nanopowder with a Cu@Ni–Co core–shell structure was synthesized from leachate by low-temperature reduction. [ABSTRACT FROM AUTHOR]

Background Two surface proteins of Rickettsia rickettsii , outer membrane protein B (OmpB) and adhesion 2 (Adr2), have been recognized as protective antigens. Herein, the immunization with both OmpB and Adr2 was performed in mice so as to explore whether their combination could induce an enhanced immunoprotection against R. rickettsii infection. Methods C3H/HeN mice were immunized with recombinant protein rAdr2 or/and rOmp-4, a fragment derived from OmpB, and then mice were challenged with R. rickettsii . After which rickettsial loads in mice were measured by quantitative PCR. The specific antibodies in mouse sera were determined by ELISA and antigen-specific cytokines secretion by mouse T cells were analyzed in vitro . Results After challenge with R. rickettsii , the mice immunized with rAdr2 or/and rOmpB-4 had significant lower rickettsial load in livers, spleens, or lungs compared to PBS mock-immunized mice. Particularly, the load in lungs of mice immunized with both rAdr2 and rOmpB-4 was significantly lower than that with either of them. High levels of specific antibodies were detected in sera from mice immunized with rAdr2 or/and rOmpB-4, but the ratios of specific IgG2a to IgG1 induced by their combination were significantly higher than that by either rAdr2 or rOmpB-4. Following stimulation with rAdr2 or/and rOmpB-4, the INF-γ secreted by CD4 + T cells from infected mice was significantly higher than that by cognate cells from uninfected mice. And the TNF-α secreted by CD4 + or CD8 + T cells from infected mice was markedly greater than that by cognate cells from uninfected mice after stimulation by their combination but not either of them. Conclusion The combination of rAdr2 and rOmpB-4 conferred an enhanced protection against R. rickettsii infection in mice, which was mainly dependent on a stronger Th1-oriented immunoresponse with greater INF-γ and TNF-α secretion by antigen-specific T cells and specific IgG2a elicited by the combination. [ABSTRACT FROM AUTHOR]

Human Q fever is recognized as a worldwide public health problem. It often occurs by inhalation of airborne aerosols contaminated with Coxiella burnetii , a gram-negative intracellular bacterium, mainly from domestic livestock. In this study, we analyzed the possibility to establish mucosal and systemic immunity against C. burnetii infection using a pulmonary delivery of chloroform-methanol residue of C. burnetii (CMR) vaccine. Mice were immunized by the intratracheal inoculation of CMR (IT-CMR) or the subcutaneous injection of CMR (SC-CMR), and the immunized mice were challenged with C. burnetii by the intratracheal route. The levels of IFN-γ, IL-12p70, IL-5, and IL-4 in the IT-CMR group in splenic T cells stimulated ex vivo were significantly higher than in the SC-CMR group. Significantly elevated sIgA to C. burnetii was detected in the bronchoalveolar lavage fluid of mice immunized by IT-CMR but not by SC-CMR, which might have contributed to the significant reduction in C. burnetii load and pathological lesions in the lungs of the mice after the challenge of C. burnetii. These results suggest that compared with SC-CMR in mice, IT-CMR was more efficient to elicit cellular and lung mucosal immune responses against aerosol infection of C. burnetii. [ABSTRACT FROM AUTHOR]

In this work, we have studied the influence of sodium in CuZnSnS (CZTS) solar cells. The CZTS films were prepared on soda lime glass substrates with and without sodium barrier layers (the glass substrate served as a sodium source). Alternatively, a 40 nm NaF layer was deposited on the metallic precursor using glass substrates with a sodium barrier layer. The SEM showed a bi-layer structure of CZTS films. The bottom layer with small grains became thicker with sodium doping. Using the UV-Raman spectroscopy, ZnS phase was observed both in the surface and interface for the sample prepared with NaF. XPS indicated that sodium was rich on the film surface and at the CZTS/Mo interface. Simultaneously the surface and interface identified to be low concentrations of Cu as well as high concentrations of Zn. The I–V curve under light indicated that the performance could be improved by controlling the amount sodium. [ABSTRACT FROM AUTHOR]