Search

Since the first successful exfoliation of graphene, the superior physical and chemical properties of two-dimensional (2D) materials, such as atomic thickness, strong in-plane bonding energy and weak inter-layer van der Waals (vdW) force have attracted wide attention. Meanwhile, there is a surge of interest in novel physics which is absent in bulk materials. Thus, vertical stacking of 2D materials could be critical to discover such physics and develop novel optoelectronic applications. Although vdW heterostructures have been grown by chemical vapor deposition, the available choices of materials for stacking is limited and the device yield is yet to be improved. Another approach to build vdW heterostructure relies on wet/dry transfer techniques like stacking Lego bricks. Although previous reviews have surveyed various wet transfer techniques, novel dry transfer techniques have been recently been demonstrated, featuring clean and sharp interfaces, which also gets rid of contamination, wrinkles, bubbles formed during wet transfer. This review summarizes the optimized dry transfer methods, which paves the way towards high-quality 2D material heterostructures with optimized interfaces. Such transfer techniques also lead to new physical phenomena while enable novel optoelectronic applications on artificial vdW heterostructures, which are discussed in the last part of this review. [ABSTRACT FROM AUTHOR]

A large-size Bi2Se3 tape electrode (BTE) was prepared by peeling off a 2 × 1 × 0.5 cm high-quality single crystal. The feasibility of using the flexible BTE as an efficient bioplatform to load Au nanoparticles and probe DNA for HIV-1 DNA electrochemical sensing was explored. Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) show that the resultant biosensor has a wide linear range from 0.1 fM to 1 pM, a low detection limit of 50 aM, excellent selectivity, reproducibility and stability, and is superior to the pM DNA detection level of Pt-Au, graphene-AuNPs hybrid biosensors. This outstanding performance is attributed to the intrinsic surface state of Bi2Se3 topological insulator in facilitating electron transfer. Therefore, BTE electrochemical biosensor platform has great potential in the application for sensitive detection of DNA biomarkers. [ABSTRACT FROM AUTHOR]

Saturable absorption may be induced at critical pumping power by nonlinear optical effects of nanomaterials, thereby making it possible to generate a high-power ultrafast laser. Recently, Bi4Br4 is theoretically predicted to be a member of topological insulators and is expected to be a promising candidate for saturable absorbers (SAs). We show here that Bi4Br4 features a large modulation depth of 42.3%. The Bi4Br4-based SA enables mode-locking operation at the near-infrared range, as demonstrated here by a 1.5 μm fiber laser with a signal-to-noise ratio (SNR) of 90 dB and a pulse duration of 172 fs. Moreover, the robustness of the Bi4Br4-based SA at relatively high power is of particular interest, which can be proved by a laser's stable operation state. The strong optical nonlinearity and robustness provided by Bi4Br4 may arouse a growing upsurge in the innovation of high-power ultrafast photonic devices and further development of photon applications. [ABSTRACT FROM AUTHOR]

The evolution of single-stranded DNA (ssDNA) assembly on octadecylamine (ODA) modified highly oriented pyrolytic graphite (HOPG) surface by heating and ultrasonic treatment has been studied for the first time. We have observed that DNA on the ODA coated HOPG surface underwent dramatic morphological changes as a function of heating and ultrasonic treatment. Ordered DNA firstly changed to random aggregates by heating and then changed to three-dimensional (3D) networks by ultrasonic treatment. This finding points to previously unknown factors that impact graphite–DNA interaction and opens new opportunities to control the deposition of DNA onto graphitic substrates. In this way, we built a cost-effective method to produce large-scale 3D ssDNA networks. All of these studies pave the way to understand the properties of DNA–solid interface, design novel nanomaterials, and improve the sensitivity of DNA biosensors. [ABSTRACT FROM AUTHOR]

Background: Growing evidence suggests an independent relationship between habitual snoring and metabolic abnormalities. Currently, there are few data available on the association between snoring and hyperuricemia. Therefore, we evaluated the cross-sectional association between snoring and serum uric acid (UA) concentration and ascertain the effects of different snoring intensities on hyperuricemia among Chinese urban adults in Nanjing.Methods: We performed a cross-sectional study including 7699 participants (4197 men and 3502 women) from Nanjing Drum Tower Hospital aged ≥18 years over a two year (ie, 2016-2018) period. All participants were divided into four groups based on Snoring scores. Questionnaires, physical examinations and biochemical tests were conducted. Hyperuricemia was defined as levels of serum UA > 6.8 mg/dL in males and >6.0 mg/dL in females. We used a generalized linear model to investigate the association between snoring and serum UA concentration and logistic regression model to investigate the association between snoring and likelihood of having hyperuricemia in the age-, sex-adjusted model and in a multivariable model adjusting for demographic factor, plasma lipid profiles, blood glucose, blood pressure, smoking, and alcohol consumption.Results: The prevalence of hyperuricemia was 10.05% in the studied population and gradually increased across the snoring scores (P < 0.0001). We found that mild snoring, moderate, and severe snoring intensity were associated with high serum UA in the age-, sex-adjusted model and in a multivariable model adjusting for demographic and lifestyle/behavioral risk factors. The association was insisted with the addition of variables related to clinical outcomes such as diabetes, hypertension, and high-cholesterol levels.Conclusions: Our results showed self-reported habitual snoring was associated with higher serum UA concentration among Chinese urban adults. Findings of this study indicate the significance of early detection and treatment of snoring to prevent hyperuricemia. [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]

A series of dense oxygen permeable dual-phase membranes with a composition of 60 wt% Ce0.8Gd0.2O2−δ-40 wt% Ba0.95La0.05Fe0.9M0.10O3−δ ( CGO- BLFM0.10, M=Fe, Nb, Zr, Zn, Sc, Y) were successfully synthesized and evaluated as potential ceramic membranes for oxy-fuel combustion. The effects of B-site doped elements in electronic-conducting phase ( BLFM0.10) on the crystal structure, microstructure, chemical compatibility, oxygen permeability, as well as chemical stability of CGO- BLFM0.10 were systematically investigated. All electronic-conducting phase BLFM0.10 oxides exhibited a pure cubic perovskite structure and showed good chemical compatibility with ionic-conducting phase CGO. CGO- BLFSc0.10 showed the best oxygen permeation stability under a pure CO2 atmosphere. CO2-corrosion on the perovskite phase is the main reason for the property deterioration of fluorite-perovskite-typed dual-phase membrane materials. The stability of dual-phase membrane materials can be effectively enhanced by reducing the basicity of electronic-conducting phase of perovskite materials. [ABSTRACT FROM AUTHOR]

Aim. Several studies have reported an association between self-reported habitual snoring and diabetes mellitus (DM); however, the results are inconsistent. Methods. Electronic databases including PubMed and EMBASE were searched. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association between snoring and DM using a random-effects model. Heterogeneity, subgroup, and sensitivity analyses were also evaluated. Begg’s, Egger’s tests and funnel plots were used to evaluate publication bias. Results. A total of eight studies (six cross sectional and two prospective cohort studies) pooling 101,246 participants were included. Of the six cross sectional studies, the summary OR and 95% CI of DM in individuals that snore compared with nonsnorers were 1.37 (95% CI: 1.20–1.57, p<0.001). There was no heterogeneity across the included studies (I2=2.9%, p=0.408). When stratified by gender, the pooled OR (95% CI) was 1.59 (1.20–2.11) in females (n=12298), and 0.89 (0.65–1.22) in males (n=4276). Of the two prospective studies, the pooled RR was 1.65 (95% CI, 1.30–2.08). Conclusions. Self-reported habitual snoring is statistically associated with DM in females, but not in males. This meta-analysis indicates a need to paying attention to the effect of snoring on the occurrence of DM in females. [ABSTRACT FROM AUTHOR]

Aim. Several studies have reported an association between self-reported habitual snoring and diabetes mellitus (DM); however, the results are inconsistent. Methods. Electronic databases including PubMed and EMBASE were searched. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association between snoring and DM using a random-effects model. Heterogeneity, subgroup, and sensitivity analyses were also evaluated. Begg’s, Egger’s tests and funnel plots were used to evaluate publication bias. Results. A total of eight studies (six cross sectional and two prospective cohort studies) pooling 101,246 participants were included. Of the six cross sectional studies, the summary OR and 95% CI of DM in individuals that snore compared with nonsnorers were 1.37 (95% CI: 1.20–1.57, p<0.001). There was no heterogeneity across the included studies (I2=2.9%, p=0.408). When stratified by gender, the pooled OR (95% CI) was 1.59 (1.20–2.11) in females (n=12298), and 0.89 (0.65–1.22) in males (n=4276). Of the two prospective studies, the pooled RR was 1.65 (95% CI, 1.30–2.08). Conclusions. Self-reported habitual snoring is statistically associated with DM in females, but not in males. This meta-analysis indicates a need to paying attention to the effect of snoring on the occurrence of DM in females. [ABSTRACT FROM AUTHOR]

Background: Microcystins LR (MC-LR) are hepatotoxic cyanotoxins that have been shown to induce reproductive toxicity, and Hypothalamic–Pituitary–Gonadal Axis (HPG) is responsible for the control of reproductive functions. However, few studies have been performed to evaluate the effects of MC-LR on HPG axis. This study aimed to investigate the MC-LR-induced toxicity in the reproductive system of mouse and focus on the HPG axis. Methods: Adult male C57BL/6 mice were exposed to various concentrations of MC-LR (0, 3.75, 7.50, 15.00 and 30.00 µg/kg body weight per day) for 1 to 14 days, and it was found that exposure to different concentrations of MC-LR significantly disturbed sperm production in the mice testes in a dose- and time-dependent manner. To elucidate the associated possible mechanisms, the serum levels of testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were assessed. Meanwhile, PCR assays were employed to detect alterations in a series of genes involved in HPG axis, such as FSH, LH, gonadotropin-releasing hormone (GnRH) and their complement receptors. Furthermore, the effect of MC-LR on the viability and testosterone production of Leydig cells were tested in vitro. Results: MC-LR significantly impaired the spermatogenesis of mice possibly through the direct or indirect inhibition of GnRH synthesis at the hypothalamic level, which resulted in reduction of serum levels of LH that lead to suppression of testosterone production in the testis of mice. Conclusions: MC-LR may be a GnRH toxin that would disrupt the reproductive system of mice. [ABSTRACT FROM AUTHOR]

Background: Several studies have reported that the tumor necrosis factor-α (TNF-α) -308G/A polymorphism is associated with susceptibility to obstructive sleep apnea-hypopnea syndrome (OSAHS). However, these results are controversial and conflicting. Objective: To evaluate the association between TNF-α-308G/A and OSAHS risk by meta-analysis. Methods: Electronic databases, including PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wanfang, and Weipu, were searched to identify relevant studies. Data were extracted from the included studies. A model-free approach using odds ratio (OR), generalized odds ratio (ORG) and 95% confidence interval (CI) of the allele contrast to assess the association between the -308G/A polymorphism and OSAHS risk. Cumulative and recursive cumulative meta-analyses (CMA) were also carried out to investigate the trend and stability of effect sizes as evidence accumulated. Results: Seven studies including 1369 OSAHS patients and 1064 controls were identified in this meta-analysis. Significant associations were derived from the variants of the allele contrast [(OR, 1.78; 95% CI, 1.45–2.18) or (ORG, 2.01; 95% CI, 1.27–3.19). CMA showed a trend of an association. Recursive CMA indicated that more evidence is needed to conclude on the status of significance. No significant publication bias was found. Conclusions: Our meta-analysis suggested that the TNF-α-308G/A polymorphism contribute to the risk of OSAHS. Further studies with larger sample should be performed to confirm our findings. [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]

Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is the most pathogenic member among Rickettsia spp. Surface-exposed proteins (SEPs) of R. rickettsii may play important roles in its pathogenesis or immunity. In this study, R. rickettsii organisms were surface-labeled with sulfo-NHS-SS-biotin and the labeled proteins were affinity-purified with streptavidin. The isolated proteins were separated by two-dimensional electrophoresis, and 10 proteins were identified among 23 protein spots by electrospray ionization tandem mass spectrometry. Five (OmpA, OmpB, GroEL, GroES, and a DNA-binding protein) of the 10 proteins were previously characterized as surface proteins of R. rickettsii. Another 5 proteins (Adr1, Adr2, OmpW, Porin_4, and TolC) were first recognized as SEPs of R. rickettsii herein. The genes encoding the 5 novel SEPs were expressed in Escherichia coli cells, resulting in 5 recombinant SEPs (rSEPs), which were used to immunize mice. After challenge with viable R. rickettsii cells, the rickettsial load in the spleen, liver, or lung of mice immunized with rAdr2 and in the lungs of mice immunized with other rSEPs excluding rTolC was significantly lower than in mice that were mock-immunized with PBS. The in vitro neutralization test revealed that sera from mice immunized with rAdr1, rAdr2, or rOmpW reduced R. rickettsii adherence to and invasion of vascular endothelial cells. The immuno-electron microscopic assay clearly showed that the novel SEPs were located in the outer and/or inner membrane of R. rickettsii. Altogether, the 5 novel SEPs identified herein might be involved in the interaction of R. rickettsii with vascular endothelial cells, and all of them except TolC were protective antigens. [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]

Coxiella burnetii is a Gram-negative bacterium that causes Q fever in humans. In the present study, 131 candidate peptides were selected from the major immunodominant proteins (MIPs) of C. burnetii due to their high-affinity binding capacity for the MHC class II molecule H2 I-Ab based on bioinformatic analyses. Twenty-two of the candidate peptides with distinct MIP epitopes were well recognized by the IFN-γ recall responses of CD4+ T cells from mice immunized with parental proteins in an ELISPOT assay. In addition, 7 of the 22 peptides could efficiently induce CD4+ T cells from mice immunized with C. burnetii to rapidly proliferate and significantly increase IFN-γ production. Significantly higher levels of IL-2, IL-12p70, IFN-γ, and TNF-α were also detected in serum from mice immunized with a pool of the 7 peptides. Immunization with the pool of 7 peptides, but not the individual peptides, conferred a significant protection against C. burnetii infection in mice, suggesting that these Th1 peptides could work together to efficiently activate CD4+ T cells to produce the Th1-type immune response against C. burnetii infection. These observations could contribute to the rational design of molecular vaccines for Q fever. [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]

Background: Rickettsia heilongjiangensis, the agent of Far-Eastern spotted fever (FESF), is an obligate intracellular bacterium. The surface-exposed proteins (SEPs) of rickettsiae are involved in rickettsial adherence to and invasion of host cells, intracellular bacterial growth, and/or interaction with immune cells. They are also potential molecular candidates for the development of diagnostic reagents and vaccines against rickettsiosis. Methods: R. heilongjiangensis SEPs were identified by biotin-streptavidin affinity purification and 2D electrophoreses coupled with ESI-MS/MS. Recombinant SEPs were probed with various sera to analyze their serological characteristics using a protein microarray and an enzyme-linked immune sorbent assay (ELISA). Results: Twenty-five SEPs were identified, most of which were predicted to reside on the surface of R. heilongjiangensis cells. Bioinformatics analysis suggests that these proteins could be involved in bacterial pathogenesis. Eleven of the 25 SEPs were recognized as major seroreactive antigens by sera from R. heilongjiangensis-infected mice and FESF patients. Among the major seroreactive SEPs, microarray assays and/or ELISAs revealed that GroEL, OmpA-2, OmpB-3, PrsA, RplY, RpsB, SurA and YbgF had modest sensitivity and specificity for recognizing R. heilongjiangensis infection and/or spotted fever. Conclusions: Many of the SEPs identified herein have potentially important roles in R. heilongjiangensis pathogenicity. Some of them have potential as serodiagnostic antigens or as subunit vaccine antigens against the disease. [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]

The emergence of multi‐drug resistant (MDR) bacteria poses a serious threat to human health. It has become imperative to develop efficient antimicrobial strategies. Here, a manganese‐doped dopamine‐derived hollow carbon sphere (MnOx/HNCS) is developed as a nanozyme and photothermal agent for the synergistic treatment of MDR bacterial infections. MnOx/HNCS possesses oxidase, superoxide dismutase, and peroxidase like activities and implements self‐cascading enzymatic catalysis to produce superoxide anion (O2•−), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH). Importantly, near‐infrared light facilitates the electron transport of MnOx/HNCS, allowing it to exhibit stable photothermal effects and photo‐enhanced enzymatic activity. Thereby MnOx/HNCS displays a broad‐spectrum synergistic antibacterial efficiency in vitro against six MDR pathogens based on the above photo‐regulated properties. In vivo experiments further demonstrate the excellent antibacterial efficiency of MnOx/HNCS in the MDR bacteria‐infected wound model. Notably, MnOx/HNCS not only has excellent disinfection capacity, but also can accelerate wound healing by stimulating the deposition of the extracellular matrix and reepithelialization. This study proposes a promising antibiotics‐alternative broad‐spectrum antibacterial strategy and paves a new avenue for the establishment of multifunctional photo‐responsive synergistic therapeutic platform. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 4 Cl can directly react with Cu 2 S leading to the formation of CuCl in the absence of oxygen. • O 2 dissociative adsorption on the Cu 2 S surface can promote NH 4 Cl dissociation. • The chlorination of Cu 2 S followed by electrodeposition of the resulting CuCl is a highly efficient process. Chalcocite (Cu 2 S) is the main source for metallurgical production of copper worldwide but it usually co-exist with nickel sulfide in nature. To develop an efficient and green process for the separation and extraction of valuable metals from high-grade matte, we performed density functional theory (DFT) calculations and experimental studies to elucidate chlorination mechanism of Cu 2 S with ammonium chloride (NH 4 Cl). First, NH 4 Cl can react with Cu 2 S directly in the absence of O 2 , leading to the formation of H 2 S and NH 3 with negative adsorption energies. Second, O 2 can promote the chlorination process by providing adsorbed O and promoting the dissociation of HCl decomposed from NH 4 Cl, leading to the formation of H 2 O and CuCl species eventually. Besides, SO 2 generated at the Cu 2 S surface after O 2 dissociative adsorption, may leading to the generation of Cl 2. Finally, the chlorination can also be achieved by the interaction between Cu 2 S and Cl 2 , which is favored thermodynamically and kinetically. Based on the computational results, low-temperature roasting experiments were performed. Cu 2 S was successfully converted into the corresponding metal chloride (CuCl) by NH 4 Cl in the absence of O 2 , but the chlorination process is incomplete with unreacted Cu 2 S. However, the conversion from Cu 2 S to CuCl is complete under air atmosphere, consistent with our computational results. Furthermore, metallic copper was successfully obtained at the cathode through electrodeposition with CuCl. The present study reveals detailed reaction mechanism between Cu 2 S and NH 4 Cl, and shows the chlorination of Cu 2 S by NH 4 Cl followed by electrodeposition of the resulting CuCl as a highly efficient and green process. [ABSTRACT FROM AUTHOR]

Aims/Introduction: Type 2 diabetes mellitus is frequently accompanied by fatty liver disease. Lipid accumulation within the liver is considered as one of the risk factors for insulin resistance. Hepatocyte growth factor (HGF) is used to treat liver dysfunction; however, the effect and mechanism of HGF on hepatic lipid metabolism are still not fully understood. Materials and Methods: Male C57BL/6 mice were induced with a high‐fat diet for 12 weeks, followed by a 4‐week treatment of HGF or vehicle saline. The levels of fasting blood glucose, fasting insulin and homeostatic model assessment of insulin resistance were calculated for insulin sensitivity. Biochemical plasma parameters were also measured to assess the effect of HGF on lipid accumulation. Additionally, genes in the lipid metabolism pathway were evaluated in palmitic acid‐treated HepG2 cells and high‐fat diet mice. Results: HGF treatment significantly decreased the levels of fasting blood glucose, hepatic triglyceride and cholesterol contents. Additionally, HGF‐regulated expression levels of sterol regulatory element‐binding protein‐1c/fatty acid synthase, peroxidase proliferator‐activated receptor‐α, and upstream nuclear receptors, such as farnesoid X receptor and small heterodimer partner. Furthermore, c‐Met inhibitor could partially reverse the effects of HGF. Conclusions: HGF treatment can ameliorate hepatic insulin resistance and steatosis through regulation of lipid metabolism. These effects might occur through farnesoid X receptor–small heterodimer partner axis‐dependent transcriptional activity. HGF reduced the levels of fasting blood glucose, blood lipid level, and improved the HFD‐fed mice. HGF significantly regulated lipogenesis‐related genes SREBP‐1c/FAS as well as PPARα, and nuclear receptors such as FXR, SHP. HGF ameliorates hyperglycemia and by improving hepatic insulin resistance and steatosis in HFD‐fed C57BL/6 mice. [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]

Layered micron-scale Ti 3 AlC 2 powders have been successfully synthesized from TiO 2 /Al 2 O 3 /C precursor by a facile electrochemical process at 900 °C and 3.1 V in molten CaCl 2 . Porous TiO 2 /Al 2 O 3 /C mixture pellet was served as the cathode and a graphite rod was employed as the anode. The influence of carbon content on the products was systematically investigated. The lattice parameters of the electrosynthesized Ti 3 AlC 2 were determined. In addition, three reaction periods from TiO 2 /Al 2 O 3 /C to Ti 3 AlC 2 including the generation of CaTiO 3 /Ca 12 Al 14 O 33 intermediate compounds, the reduction of the oxides/compounds and the formation of Ti 3 AlC 2 were investigated and confirmed. The results show that the electrochemical process is of great potential to the facile synthesis of Ti 3 AlC 2 , which may also have implication for the production of other M n +1 AX n phases from their inexpensive and abundantly available oxides precursors. [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]

Coxiella burnetii is the etiological agent of the zoonotic disease Q fever, which is featured by its ability to replicate in acid vacuoles resembling the lysosomal network. One key virulence determinant of C. burnetii is the Dot/Icm system that transfers more than 150 effector proteins into host cells. These effectors function to construct the lysosome-like compartment permissive for bacterial replication, but the functions of most of these effectors remain elusive. In this study, we used an affinity tag purification mass spectrometry (AP-MS) approach to generate a C. burnetii-human protein-protein interaction (PPI) map involving 53 C. burnetii effectors and 3480 host proteins. This PPI map revealed that the C. burnetii effector CBU0425 (designated CirB) interacts with most subunits of the 20S core proteasome. We found that ectopically expressed CirB inhibits hydrolytic activity of the proteasome. In addition, overexpression of CirB in C. burnetii caused dramatic inhibition of proteasome activity in host cells, while knocking down CirB expression alleviated such inhibitory effects. Moreover, we showed that a region of CirB that spans residues 91–120 binds to the proteasome subunit PSMB5 (beta 5). Finally, PSMB5 knockdown promotes C. burnetii virulence, highlighting the importance of proteasome activity modulation during the course of C. burnetii infection. Author summary: As the causative agent of Q fever, C. burnetii colonizes host cells by transferring effector proteins into the host cytoplasm through its Dot/Icm secretion system to construct a replicative vacuole. The function of effectors remains largely unknown. Here, we performed a large-scale AP-MS screen to analyze the interactions among C. burnetii effectors and human proteins. These analyses found that CirB functions as an inhibitor of host proteasome activity, revealing that proteasome activity is important for intracellular survival of C. burnetii. Our data have laid the foundation for future exploring the molecular mechanisms underlying the roles of C. burnetii effectors in its virulence and for the identification of novel potential drug targets for the development of novel therapeutic treatment for C. burnetii infection. [ABSTRACT FROM AUTHOR]

Clinical therapy of multidrug resistant (MDR) bacteria‐induced deep‐tissue infections such as pneumonia is highly challenging. Ultrasound (US)‐induced sonodynamic therapy (SDT) is a promising strategy for treatment of deep‐tissue diseases given the strong tissue penetration of US. Here, ZIF‐8‐derived carbon@TiO2 nanoparticles (ZTNs) are developed as inhalable sonosensitizers for bacterial pneumonia. ZTNs upon US irradiation exhibit an excellent efficacy to produce reactive oxygen species (ROS) and thereby to kill Gram‐negative MDR bacteria in vitro. Taking advantage of aerosolized intratracheal inoculation, ZTNs can be precisely delivered to lung infection sites, and display an effective SDT‐based elimination of Gram‐negative MDR bacteria in the lung infection models of immunocompetent or immunodeficient mice. Particularly, ZTNs upon US irradiation give a 100% survival rate in the severely immunodeficient NOD/SCID mice with a lethal bacterial pneumonia. In addition, ZTNs have no obvious toxicity at both cellular and animal levels. Metal–organic‐framework‐derived nanoparticles as safe and efficient inhalable sonosensitizer have a great potential to be used for the clinical antibiotics‐alternative treatment of MDR bacterial pneumonia. This study presents a new paradigm for SDT‐based treatment of deep‐tissue bacterial infections, and will expand the nanomedicine application of inorganic sonosensitizers. [ABSTRACT FROM AUTHOR]

Photothermal therapy based on conjugated polymers represents a promising antibacterial strategy but still possesses notable limitations. Herein, degradable pseudo conjugated polymers (PCPs) containing photothermal molecular backbones and reactive oxygen species (ROS)‐sensitive thioketal bonds are designed. Triphenylphosphine (PPh3) is introduced into PCPs to generate phosphonium‐based PCPs (pPCPs), which further assembled with hyaluronic acid into pPCP nanoparticles (pPCP‐NPs). pPCP‐NPs with quaternary phosphonium cations selectively anchor on and destroy bacterial cell membranes through electrostatic action. Under 1064 nm laser irradiation, pPCP‐NPs (pPCP‐NPs/+L) produce near‐infrared‐II (NIR‐II) photothermal antibacterial effect, thereby killing bacteria in a sustained manner. pPCP‐NPs are readily degraded upon ROS abundant at infection sites, therefore exhibiting enough biosafety. pPCP‐NPs/+L display an almost 100% bacterial inhibition rate in vitro and resultin a nearly complete recovery of bacteria‐induced mouse wounds. A further metabolomics analysis denotes that pPCP‐NPs/+L work in a concerted way to induce bacterial DNA damage, inhibit bacterial carbon/nitrogen utilization and amino acid/nucleotide synthesis. Taken together, degradable pPCP‐NPs with both NIR‐II photothermal effect and cationic phosphonium structural bacteriostasis provide a new avenue for antibiotics‐alternative anti‐infection therapy. [ABSTRACT FROM AUTHOR]

Background: Coxiella burnetii (Cb) is the causative agent of the zoonotic disease Q fever which is distributed worldwide. Molecular typing of Cb strains is essential to find out the infectious source and prevent Q fever outbreaks, but there has been a lack of typing data for Cb strains in China. The aim of this study was to investigate the genotypes of Cb strains in wild rats in Yunnan Province, China. Results: Eighty-six wild rats (Rattus flavipectus) were collected in Yunnan Province and 8 of the 86 liver samples from the wild rats were positive in Cb-specific quantitative PCR (qPCR). The Cb strains from the 8 rats were then typed into 3 genotypes using 10-spacer multispacer sequence typing (MST), and 2 of the 3 genotypes were recognized as novel ones. Moreover, the Cb strains in the wild rats were all identified as genotype 1 using 6-loci multilocus variable number of tandem repeat analysis (MLVA). Conclusions: This is the first report of genotypic diversity of Cb strains from wild rats in China. Further studies are needed to explore the presence of more genotypes and to associate the genotypes circulating in the wildlife-livestock interaction with those causing human disease to further expand on the epidemiological aspects of the pathogen. [ABSTRACT FROM AUTHOR]

The obligate intracellular bacteria, Rickettsia rickettsii and Coxiella burnetii, are the potential agents of bio-warfare/bio-terrorism. Here C3H/HeN mice were immunized with a recombinant protein fragment rOmp-4 derived from outer membrane protein B, a major protective antigen of R. rickettsii, combined with chloroform-methanol residue (CMR) extracted from phase I C. burnetii organisms, a safer Q fever vaccine. These immunized mice had significantly higher levels of IgG1 and IgG2a to rOmpB-4 and interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), two crucial cytokines in resisting intracellular bacterial infection, as well as significantly lower rickettsial loads and slighter pathological lesions in organs after challenge with R. rickettsii, compared with mice immunized with rOmpB-4 or CMR alone. Additionally, after challenge with C. burnetii, the coxiella loads in the organs of these mice were significantly lower than those of mice immunized with rOmpB-4 alone. Our results prove that CMR could markedly potentiate enhance the rOmpB-4-specific immunoprotection by promoting specific and non-specific immunoresponses and the immunization with the protective antigen of R. rickettsii combined with CMR of C. burnetii could confer effective protection against infection of R. rickettsii or C. burnetii. [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]

Bismuth bromide (α-Bi4Br4) can demonstrate various exotic topological states, including higher-order topological insulator with hinge states and quantum spin Hall insulator with helical edge states. To date, α-Bi4Br4 nanowires can be obtained by using the exfoliation method from the bulk. However, it is still a great challenge to efficiently prepare α-Bi4Br4 nanowires suitable for potential applications, e.g., saturable absorber in ultrafast pulsed fiber lasers. Here, we report the controllable growth of α-Bi4Br4 thin films consisting of nanowires via molecular beam epitaxy technique. We show that the morphology of the α-Bi4Br4 nanowires depends on the growth temperature and BiBr3 flux. In addition, we also achieve α-Bi4Br4 nanowires on NbSe2 and gold substrates. Furthermore, we performed the saturable absorption property of α-Bi4Br4 thin films with a modulation depth of 21.58% and mode-locking at 1556.4 nm with a pulse width of 375 fs in the pulsed fiber lasers. Those results demonstrate the synthesis of quasi-1D topological material α-Bi4Br4, which is expected to be used for the fundamental research of topological physics and potential applications in optical devices. [ABSTRACT FROM AUTHOR]

• Using electrochemical biosensors for rapid detection of SARS-CoV-2 gene fragments. • Electrode material selection is Bi2Se3 single crystal obtained by mechanical peeling. • The peak current has a linear relationship with the logarithm of DNA concentration. • There is excellent specificity in identifying DNA, RNA, and viruses. • Sensors can clearly distinguish between positive and negative results. In this study, we have designed an electrochemical biosensor based on topological material Bi 2 Se 3 for the sensitive detection of SARS-CoV-2 in the COVID-19 pandemic. Flake-shaped Bi 2 Se 3 was obtained directly from high-quality single crystals using mechanical exfoliation, and the single-stranded DNA was immobilized onto it. Under optimal conditions, the peak current of the differential pulse voltammetry method exhibited a linear relationship with the logarithm of the concentration of target-complementary-stranded DNA, ranging from 1.0 × 10-15 to 1.0 × 10-11 M, with a detection limit of 3.46 × 10-16 M. The topological material Bi 2 Se 3 , with Dirac surface states, enhanced the signal-to-interference plus noise ratio of the electrochemical measurements, thereby improving the sensitivity of the sensor. Furthermore, the electrochemical sensor demonstrated excellent specificity in recognizing RNA. It can detect complementary RNA by amplifying and transcribing the initial DNA template, with an initial DNA template concentration ranging from 1.0 × 10-18 to 1.0 × 10-15 M. Furthermore, the sensor also effectively distinguished negative and positive results by detecting splitting-synthetic SARS-CoV-2 pseudovirus with a concentration of 1 copy/μL input. Our work underscores the immense potential of the electrochemical sensing platform based on the topological material Bi 2 Se 3 in the detection of pathogens during the rapid spread of acute infectious diseases. [ABSTRACT FROM AUTHOR]

Background: Hard ticks act as arthropod vectors in the transmission of human and animal pathogens and are widely distributed in northern China. The aim of this study is to screen the important tick-borne pathogens (TBPs) carried by hard ticks in Inner Mongolia using metagenomic next-generation sequencing (mNGS) and to estimate the risk of human infection imposed by tick bites. Methods: The adult Dermacentor nuttalli (n = 203) and Ixodes persulcatus (n = 36) ticks feeding on cattle were collected. The pooled DNA samples prepared from these ticks were sequenced as the templates for mNGS to survey the presence of TBPs at the genus level. Individual tick DNA samples were detected by genus--specific or group-specific nested polymerase chain reaction (PCR) of these TBPs and combined with DNA sequencing assay to confirm the results of mNGS. Results: R. raoultii (45.32%, 92/203), Candidatus R. tarasevichiae (5.42%, 11/203), Anaplasma sp. Mongolia (26.60%, 54/203), Coxiella-like endosymbiont (CLE) (53.69%, 109/203), and Babesia venatorum (7.88%, 16/203) were detected in D. nuttalli, while R. raoultii (30.56%, 11/36), Anaplasma sp. Mongolia (27.80%, 10/36), and CLE (27.80%, 10/36) were detected in I. persulcatus. The double- and triple-pathogen/endosymbiont co-infections were detected in 40.39% of D. nuttalli and 13.89% of I. persulcatus, respectively. The dual co-infection with R. raoultii and CLE (14.29%, 29/203) and triple co-infection with R. raoultii, Anaplasma sp. Mongolia, and CLE (13.79%, 28/203) were most frequent in D. nuttalli. Conclusions: This study provides insight into the microbial diversity of D. nuttalli and I. persulcatus in Inner Mongolia, China, reporting for the first time that Candidatus R. tarasevichiae had been found in D. nuttalli in China, and for the first time in the world that Anaplasma sp. Mongolia has been detected in I. persulcatus. This study proves that various vertically transmitted pathogens co-inhabit D. nuttalli and I. persulcatus, and indicates that cattle in Inner Mongolia are exposed to several TBPs. [ABSTRACT FROM AUTHOR]

Pantoea agglomerans YS19 is a diazotrophic endophyte isolated from rice ( Oryza sativa cv. Yuefu) grown in a temperate-climatic region in west Beijing (China). The colonization of YS19 on host rice was studied in this paper. It was revealed that YS19 colonizes in all the tissues of rice seedlings, including roots (dominantly at elongation regions, lateral root junctions, root hairs and root caps), stems and leaves. More YS19 colonizes in stem and leaves (1.40 × 105 CFU mg−1 fresh weight) than that in roots (3.60 × 104 CFU mg−1). Symplasmata, a kind of adaptive structure of the strain for its endophytic living, were repeatedly observed to form inside root or stem cortex parenchyma tissues, as well as on leaf surfaces and also rhizoplanes. A novel matrix protein (SPM43.1) with its expression paralleling to the formation of symplasmata was captured, whose meaning in structural construction of symplasmata was also discussed. [ABSTRACT FROM AUTHOR]

Background: Hard ticks act as arthropod vectors in the transmission of human and animal pathogens and are widely distributed in northern China. The aim of this study is to screen the important tick-borne pathogens (TBPs) carried by hard ticks in Inner Mongolia using metagenomic next-generation sequencing (mNGS) and to estimate the risk of human infection imposed by tick bites. Methods: The adult Dermacentor nuttalli (n = 203) and Ixodes persulcatus (n = 36) ticks feeding on cattle were collected. The pooled DNA samples prepared from these ticks were sequenced as the templates for mNGS to survey the presence of TBPs at the genus level. Individual tick DNA samples were detected by genus--specific or group-specific nested polymerase chain reaction (PCR) of these TBPs and combined with DNA sequencing assay to confirm the results of mNGS. Results: R. raoultii (45.32%, 92/203), Candidatus R. tarasevichiae (5.42%, 11/203), Anaplasma sp. Mongolia (26.60%, 54/203), Coxiella-like endosymbiont (CLE) (53.69%, 109/203), and Babesia venatorum (7.88%, 16/203) were detected in D. nuttalli, while R. raoultii (30.56%, 11/36), Anaplasma sp. Mongolia (27.80%, 10/36), and CLE (27.80%, 10/36) were detected in I. persulcatus. The double- and triple-pathogen/endosymbiont co-infections were detected in 40.39% of D. nuttalli and 13.89% of I. persulcatus, respectively. The dual co-infection with R. raoultii and CLE (14.29%, 29/203) and triple co-infection with R. raoultii, Anaplasma sp. Mongolia, and CLE (13.79%, 28/203) were most frequent in D. nuttalli. Conclusions: This study provides insight into the microbial diversity of D. nuttalli and I. persulcatus in Inner Mongolia, China, reporting for the first time that Candidatus R. tarasevichiae had been found in D. nuttalli in China, and for the first time in the world that Anaplasma sp. Mongolia has been detected in I. persulcatus. This study proves that various vertically transmitted pathogens co-inhabit D. nuttalli and I. persulcatus, and indicates that cattle in Inner Mongolia are exposed to several TBPs. [ABSTRACT FROM AUTHOR]

Background: Coxiella burnetii is an obligate intracellular Gram-negative bacterium that causes a zoonotic disease commonly called Q fever globally. In this study, an up-converting phosphor technology-based lateral flow (UPT-LF) assay was established for the rapid and specific detection of phase I strains of C. burnetii. Results: Specific monoclonal antibodies (10B5 and 10G7) against C. burnetii phase I strains were prepared and selected for use in the UPT-LF assay by the double-antibody-sandwich method. The detection sensitivity of the Coxiella-UPT-LF was 5 × 104 GE/ml for a purified C. burnetii phase I strain and 10 ng/ml for LPS of C. burnetii Nine Mile phase I (NMI). Good linearity was observed for C. burnetii phase I and NMI LPS quantification (R2 ≥ 0.989). The UPT-LF assay also exhibited a high specificity to C. burnetii, without false-positive results even at 108 GE/ml of non-specific bacteria, and good inclusivity for detecting different phase I strains of C. burnetii. Moreover, the performance of the Coxiella-UPT-LF assay was further confirmed using experimentally and naturally infected samples. Conclusions: Our results indicate that Coxiella-UPT-LF is a sensitive and reliable method for rapid screening of C. burnetii, suitable for on-site detection in the field. [ABSTRACT FROM AUTHOR]

Q fever is a worldwide zoonosis caused by Coxiella burnetii. Human Q fever is typically acquired through inhalation of contaminated aerosols, resulting in an initial pulmonary infection. In this study, BALB/c mice were infected with C. burnetii via an intratracheal (IT) route using a non-invasive aerosol pulmonary delivery device to directly place the living C. burnetii organisms into the lungs of the mice. The bacterial loads, pathological lesions, and antibody and cellular responses were analyzed and compared with those of mice infected via an intraperitoneal (IP) route. Compared with mice infected via an IP route, mice infected via an IT route exhibited a higher bacterial load and more severe pathological lesions in the heart and lungs at days 3 and 7 post-infection (pi). The levels of interferon-γ and IL-12p70 in the serum of mice infected via the IT route were significantly higher than those of mice infected via the IP route at day 3 pi. In conclusion, this murine model of acute C. burnetii infection via IT inoculation closely resembles the natural route of C. burnetii infection than that of IP injection. Thus, this newly developed model will be useful for investigating the pathogenesis and immunity of C. burnetii aerosol infection, as well as for the evaluation of therapeutic drugs and preventive vaccines of Q fever. [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]

Various structures of two-dimensional (2D) WSe2 were controllably grown in a chemical vapor deposition (CVD) system. Using salt as the co-solvent and surfactant, we were able to grow monolayer single-crystalline WSe2 flakes with lateral size of up to 215 μm and monolayer polycrystalline WSe2 with lateral size of a few millimeters on amorphous SiO2 substrates. Optical microscopy, atomic force microscopy, Raman spectra, photoluminescence spectra and X-ray photoelectron spectra measurements disclosed high quality of as-grown 2D WSe2. Moreover, multilayer WSe2 flakes with spiral dislocations and uniform size were also achieved. Our study demonstrates that the salt-assisted CVD technique can be applied for the controllable synthesis of 2D transition metal dichalcogenides with various structures and morphologies, paving the way for developing novel catalysts and electronic devices. [ABSTRACT FROM AUTHOR]

Coxiella burnetii is a gram-negative bacterium that causes acute and chronic Q fever. Because of the severe adverse effect of whole-cell vaccination, identification of immunodominant antigens of C. burnetii has become a major focus of Q fever vaccine development. We hypothesized that secreted C. burnetii type IV secretion system (T4SS) effectors may represent a major class of CD8+ T-cell antigens, owing to their cytosolic localization. Twenty-nine peptides were identified that elicited robust CD8+ T-cell interferon γ (IFN-γ) recall responses from mice infected with C. burnetii. Interestingly, 22 of 29 epitopes were derived from 17 T4SS-related proteins, none of which were identified as immunodominant antigens by using previous antibody-guided approaches. These epitopes were expressed in an attenuated Listeria monocytogenes vaccine strain. Immunization with recombinant L. monocytogenes vaccines induced a robust CD8+ T-cell response and conferred measurable protection against C. burnetii infection in mice. These data suggested that T4SS effectors represent an important class of C. burnetii antigens that can induce CD8+ T-cell responses. We also showed that attenuated L. monocytogenes vaccine vectors are an efficient antigen-delivery platform that can be used to induce robust protective CD8+ T-cell immune responses against C. burnetii infection. [ABSTRACT FROM AUTHOR]

In this work, we designed a facile and label-free electrochemical biosensor based on intrinsic topological insulator (TI) Bi 2 Se 3 and peptide for the detection of immune checkpoint molecules. With topological protection, Bi 2 Se 3 could have robust surface states with low electronic noise, which was beneficial for the stable and sensitive electron transport between electrode and electrolyte interface. The peptides are easily synthesized and chemically modified, and have good biocompatibility and bioavailability, which is a suitable candidate as the recognition units for immune checkpoint molecules. Therefore, the peptide/Bi 2 Se 3 was developed as a suitable working electrode for the electrochemical biosensor. The basic performance of the designed peptide/Bi 2 Se 3 biosensor was investigated to determine the Anti-HA Tag Antibody and PD-L1 molecules. The linear detection range was from 3.6 × 10−10 mg mL−1 to 3.6 × 10−5 mg mL−1, and the detection limit was 1.07 × 10−11 mg mL−1. Moreover, the biosensor also displayed good selectivity and stability. [Display omitted] • Sensitive electrochemical biosensors combined with topological materials and peptides. • High-quality and large-scale topological crystal with few defects as electrodes. • Effective recognition units of peptides for the immune checkpoint. • A large detection range, good selectivity and stability with low detection limit of the sensing assay. • Excellent discernment in the complicated serum environment for clinical application. [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]

In this work, we reported TEM observations of several CdS thin films prepared by close space submission, sputtering, chemical bath deposition and electronic deposition technologies. The CdS layers prepared by close space submission and sputtering methods had larger grains (50–80 nm), while the CdS layers deposited by chemical bath had very small grains with the size of 5–10 nm. Electro deposited CdS yielded more like an epitaxial film. The optical and chemical properties showed good quality of CdS films prepared by all methods. In this work we proposed a suitable CdS multilayer structure to use it as a window layer in thin film solar cells. [ABSTRACT FROM AUTHOR]

Rickettsia heilongjiangensis is the pathogen of Far eastern spotted fever, and T-cell immunoglobulin and mucin domain protein 3 (Tim-3) is expressed in human vascular endothelial cells, the major target cells of rickettsiae. In the present study, we investigated the effects of altered Tim-3 expression in vivo in mice and in vitro in human endothelial cells, on day 3 after R. heilongjiangensis infection. Compared with corresponding controls, rickettsial burdens both in vivo and in vitro were significantly higher with blocked Tim-3 signaling or silenced Tim-3 and significantly lower with overexpressed Tim-3. Additionally, the expression of inducible nitric oxide synthase and interferon γ in endothelial cells with blocked Tim-3 signaling or silenced Tim-3 was significantly lower, while the expression of inducible nitric oxide synthase, interferon γ, and tumor necrosis factor α in transgenic mice with Tim-3 overexpression was significantly higher. These results reveal that enhanced Tim-3 expression facilitates intracellular rickettsial killing in a nitric oxide-dependent manner in endothelial cells during the early phase of rickettsial infection. [ABSTRACT FROM AUTHOR]

Background: Far-eastern spotted fever (FESF) is an important emerging infectious disease in Northeast Asia. The laboratory diagnosis of FESF in hospitals is mainly based on serological methods. However, these methods need to cultivate rickettsial cells as diagnostic antigens, which is both burdensome and dangerous.Methods: Eleven surface-exposed proteins (SEPs) were identified in our previous study and their recombinant proteins (rSEPs) fabricated on a microarray were serologically analyzed with seventeen paired sera from patients suffered from FESF in this study.Results: All the rSEPs showed sensitivities of between 53% and 82% to acute-phase sera and of between 65% and 82% to convalescent-phase sera, and all the rSEPs except rRplA showed specificities of between 80% and 95%. The combination assay of two, three, or four of the four rSEPs (rOmpA-2, rOmpB-3, rRpsB, and rSdhB) showed better sensitivities of between 76% and 94% to the acute-phase sera or between 82% and 100% to the convalescent-phase sera and acceptable specificities of between 75% and 90%.Conclusions: Our results suggest that the four rSEPs are more likely candidate antigens for serological diagnosis of FESF. [ABSTRACT FROM AUTHOR]

Coxiella burnetii is the etiological agent of human Q fever. In this study, adaptive transfer of mouse bone marrow-derived dendritic cells (BMDCs) stimulated with C. burnetii antigen, phase I whole-cell antigen (PIAg), lipopolysaccharide (LPS)-removed PIAg (PIIAg), protein antigen Com1, or SecB significantly reduced coxiella burden in recipient mice compared with control mice. Mice that received PIIAg-pulsed BMDCs displayed substantially lower coxiella burden than recipient mice of PIAg-pulsed BMDCs after C burnetii challenge. The protection offered by the antigen-activated BMDCs was correlated with the increased proliferation of helper T (T(H)) T(H)1 CD4(+) cells, preferential development of T(H)17 cells, and impaired expansion of regulatory T lymphocytes. Our results suggest that PIIAg is far superior to PIAg in activating BMDCs to confer protection against C. burnetii in vivo, whereas Com1 and SecB are protective antigens because Com1- or SecB-pulsed BMDCs confer partial protection. [ABSTRACT FROM AUTHOR]

• A potential photo-catalyst thin film material; • High optical absorption in visible light range; • A great amount of nanoflake structures at the BiCuSeO surface. Photoelectrochemical cells with semiconductor photoelectrodes for water splitting have attracted increased interest in the field of solar energy, which requires suitable photoelectrode materials with excellent electrical properties and a visible light response. In this article, BiCuSeO thin films were obtained by evaporating CuBi precursors followed by a selenization treatment. The annealing temperatures (350 - 475°C) and oxygen concentrations (0 - 33%) were optimized to obtain high-quality thin films. A great number of thin flakes were found on the surface of the optimized films, which could benefit the catalyst application. The optical absorption measurement indicated a high absorption coefficient for BiCuSeO thin films in the 300 nm to 700 nm range. Photoelectrochemical analyses of BiCuSeO thin films showed that a large photocurrent density of 10 mA/cm2 was achieved at a relatively low bias, −0.55 V, versus reversible hydrogen electrode, significant for a strong photoresponse for BiCuSeO thin films exhibiting flakes on the surface. These results indicate that BiCuSeO is a potential material for photocatalyst applications. [ABSTRACT FROM AUTHOR]