Double cross-linked 3D layered PBI proton exchange membranes for stable fuel cell performance above 200 °C.

Phosphoric acid doped proton exchange membranes often experience performance degradation above 200 °C due to membrane creeping and phosphoric acid evaporation, migration, dehydration, and condensation. To address these issues, here we present gel-state polybenzimidazole membranes with double cross-linked three-dimensional layered structures via a polyphosphoric acid sol-gel process, enabling stable operation above 200 °C. These membranes, featuring proton-conducting cross-linking phosphate bridges and branched polybenzimidazole networks, effectively anchor and retain phosphoric acid molecules, prevent 96% of its dehydration and condensation, improve creep resistance, and maintain excellent proton conductivity stability. The resulting membrane, with superior through-plane proton conductivity of 0.348 S cm-1, delivers outstanding peak power densities ranging from 1.20-1.48 W cm-2 in fuel cells operated at 200-240 °C and a low voltage decay rate of only 0.27 mV h-1 over a 250-hour period at 220 °C, opening up possibilities for their direct integration with methanol steam reforming systems.

Membrane vesicles derived from Listeria monocytogenes might be a potential antigen delivery vector.

Membrane vesicles (MVs) derived from Listeria monocytogenes (LM) have a natural nanoscale size and contain a variety of bacterial components. We speculated that LM MVs may be a novel delivery vector, but it is necessary to evaluate the safety and immunogenicity of LM MVs in vivo. Here, we isolated LM MVs and tested their safety and immunogenicity both in vitro and in vivo. The results showed that LM MVs stimulated RAW264.7 cells and DC2.4 cells to secrete the inflammatory cytokines IL-1ß, TNF-α, IL-6 and IL-10. Intraperitoneal injection of LM MVs at 80 µg per C57BL/6 mouse did not cause lethal effects or irreversible pathological changes in major organs, indicating that LM MVs were safe. Intraperitoneal immunization of C57BL/6 mice twice with LM MVs mainly induced a high level of LM MV-specific IgG antibodies. In addition, we subcutaneously injected C57BL/6 mice with a mixture of ovalbumin and LM MVs and found that LM MVs exhibited a humoral immune adjuvant effect equal to that of the same amount of alum. The results of this study indicated that LM MVs have good safety and effective immunogenicity and may act as humoral immune adjuvants. Therefore, LM MVs are a potential new choice for antigen and drug delivery vectors.

Microbiota and mycobiota in bronchoalveolar lavage fluid of silicosis patients.

BACKGROUND: The contribution of bronchoalveolar lavage fluid (BALF) microbiota and mycobiota to silicosis has recently been noticed. However, many confounding factors can influence the accuracy of BALF microbiota and mycobiota studies, resulting in inconsistencies in the published results. In this cross-sectional study, we systematically investigated the effects of "sampling in different rounds of BALF" on its microbiota and mycobiota. We further explored the relationship between silicosis fatigue and the microbiota and mycobiota. METHODS: After obtaining approval from the ethics board, we collected 100 BALF samples from 10 patients with silicosis. Demographic data, clinical information, and blood test results were also collected from each patient. The characteristics of the microbiota and mycobiota were defined using next-generation sequencing. However, no non-silicosis referent group was examined, which was a major limitation of this study. RESULTS: Our analysis indicated that subsampling from different rounds of BALF did not affect the alpha- and beta-diversities of microbial and fungal communities when the centrifuged BALF sediment was sufficient for DNA extraction. In contrast, fatigue status significantly influenced the beta-diversity of microbes and fungi (Principal Coordinates Analysis, P = 0.001; P = 0.002). The abundance of Vibrio alone could distinguish silicosis patients with fatigue from those without fatigue (area under the curve = 0.938, 95% confidence interval [CI] 0.870-1.000). Significant correlations were found between Vibrio and haemoglobin levels (P < 0.001, ρ = -0.64). CONCLUSIONS: Sampling in different rounds of BALF showed minimal effect on BALF microbial and fungal diversities; the first round of BALF collection was recommended for microbial and fungal analyses for convenience. In addition, Vibrio may be a potential biomarker for silicosis fatigue screening.

Three Specific Potential Epitopes That Could Be Recognized by T Cells of Convalescent COVID-19 Patients Were Identified From Spike Protein.

The current coronavirus disease 2019 (COVID-19) vaccines are used to prevent viral infection by inducing neutralizing antibody in the body, but according to the existing experience of severe acute respiratory syndrome coronavirus (SARS) infection, T-cell immunity could provide a longer durable protection period than antibody. The research on SARS-CoV-2-specific T-cell epitope can provide target antigen for the development and evaluation of COVID-19 vaccines, which is conducive to obtain COVID-19 vaccine that can provide long-term protection. For screening specific T-cell epitopes, a SARS-CoV-2 S protein peptide library with a peptide length of 15 amino acids was synthesized. Through flow cytometry to detect percentage of IFN-γ+ T cells after mixed COVID-19 convalescent patients' peripheral blood mononuclear cell with peptide library, seven peptides (P77, P14, P24, P38, P48, P74, and P84) that can be recognized by the T cells of COVID-19 convalescent patients were found. After excluding the nonspecific cross-reactions with unexposed population, three SARS-CoV-2-specific T-cell potential epitopes (P38, P48, and P84) were finally screened with the positive reaction rates between 15.4% and 48.0% in COVID-19 convalescent patients. This study also provided the HLA allele information of peptide-positive-response COVID-19 convalescent patients, thus predicting the population coverage of these three potential epitopes. Some HLA alleles showed higher frequency of occurrence in COVID-19 patients than in total Chinese population but no HLA alleles related to the T-cell peptide response and the severity of COVID-19. This research provides three potential T-cell epitopes that are helpful for the design and efficacy evaluation of COVID-19 vaccines. The HLA information provided by this research supplies reference significance for subsequent research such as finding the relation of HLA genotype with disease susceptibility.

Drug resistance characteristics of Mycobacterium tuberculosis isolates obtained between 2018 and 2020 in Sichuan, China.

We investigated the drug resistance of Mycobacterium tuberculosis isolates from patients with tuberculosis (TB) and HIV, and those diagnosed with only TB in Sichuan, China. TB isolates were obtained from January 2018 to December 2020 and subjected to drug susceptibility testing (DST) to 11 anti-TB drugs and to GeneXpert MTB/RIF testing. The overall proportion of drug-resistant TB (DR-TB) isolates was 32.1% (n = 10 946). HIV testing was not universally available for outpatient TB cases, only 29.5% (3227/10 946) cases had HIV testing results. The observed proportion of multidrug-resistant TB (MDR-TB) isolates was almost double than that of the national level, with approximately 1.5% and 0.1% of the isolates being extensively drug resistant and universally drug resistant, respectively. The proportions of resistant isolates were generally higher in 2018 and 2019 than in 2020. Furthermore, the sensitivities of GeneXpert during 2018-2020 demonstrated a downward trend (80.9, 95% confidence intervals (CI) 76.8-85.0; 80.2, 95% CI 76.4-84.1 and 75.4, 95% CI 70.7-80.2, respectively). Approximately 69.0% (7557/10 946) of the TB cases with DST results were subjected to GeneXpert detection. Overall, the DR-TB status and the use of GeneXpert in Sichuan have improved, but DR-TB challenges remain. HIV testing for all TB cases is recommended.

Omnidirectional ghost imaging system and unwrapping-free panoramic ghost imaging.

Ghost imaging (GI) is an unconventional imaging method that reconstructs the object information via light-intensity correlation measurements. However, at present, the field of view (FOV) of this method is limited to the illumination range of light patterns. To enlarge the FOV of GI efficiently, we propose an omnidirectional GI system (OGIS) that can achieve a 360° omnidirectional FOV only via the addition of a curved mirror. The OGIS features retina-like annular patterns designed as a log-polar structure and can obtain the undistorted unwrapping-free panoramic images with uniform resolution. This research presents a new, to the best of our knowledge, perspective for the applications of GI, such as pipeline detection, a panoramic situation awareness for autonomous vehicles.

[Extraction, Characterization and Immune Effect Analysis of Listeria Monocytogenes Membrane Vesicles].

OBJECTIVE: To establish a method for extracting Listeria monocytogenesmembrane vesicles (LM-MVs) and to analyze the characteristics of LM-MVs and their ability to induce innate immune effect in vitro so as to lay the foundation for research into using LM-MVs as vaccine carrier and drug delivery platform. METHODS: The membrane vesicles secreted by Listeria monocytogenes were extracted through a continuous process, including culturing, centrifugation, filtration, ultrafiltration concentration and ultracentrifugation. The morphological characteristics of LM-MVs were observed with transmission electron microscope, and particle size distribution were measured by dynamic light scattering analysis. SDS-PAGE and Western blot were used to analyze the protein composition of LM-MVs. CCK-8 cell proliferation and toxicity determination experiments were done to analyze their effect on the proliferation of innate immune cells, and qPCR was used to analyze their ability to induce innate immune responses. RESULTS: A method for extracting LM-MVs was successfully established. Under the transmission electron microscope, LM-MVs presented a nearly circular film-like structure, and dynamic light scattering analysis showed that their sizes were between 65 and 190 nm. SDS-PAGE and Western blot showed that LM-MVs contained proteins, including listeriolysin O (LLO). CCK-8 cell proliferation and toxicity experiment showed that after intervention with 10, 20 and 50 µg/mL of LM-MVs for 24 hours, the proliferation rate of DC 2.4 mouse dendritic cell line was higher than that of non-interventional DC 2.4 cells ( P<0.05); after intervention with 0.1, 1, 10, 20 and 50 µg/mL of LM-MVs for 24 hours, the proliferation rate of RAW 264.7 cells was higher than that of non-interventional RAW 264.7 cells ( P<0.01). The results of qPCR showed that, after intervention with 50 µg/mL of LM-MVs, the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6 and IL-10 in RAW 264.7 cells were higher than those of non-intervention control cells ( P<0.05). CONCLUSIONS: The method established in the study can be used to extract LM-MVs. The extracted LM-MVs have a diameter of 65-190 nm and a nearly circular membrane-like structure. They can secrete a variety of protein components and stimulate innate immune responses.

A newly identified linear epitope on non-RBD region of SARS-CoV-2 spike protein improves the serological detection rate of COVID-19 patients.

BACKGROUND: Serological test is helpful in confirming and tracking infectious diseases in large population with the advantage of fast and convenience. Using the specific epitope peptides identified from the whole antigen as the detection antigen is sensitive and relatively economical. The development of epitope peptide-based detection kits for COVID-19 patients requires comprehensive information about epitope peptides. But the data on B cell epitope of SARS-CoV-2 spike protein is still limited. More importantly, there is a lack of serological data on the peptides in the population. In this study, we aimed to identify the B cell epitope peptides of spike protein and detect the reactivity in serum samples, for further providing data support for their subsequent serological applications. RESULTS: Two B cell linear epitopes, P104 and P82, located in non-RBD region of SARS-CoV-2 S protein were identified by indirect ELISA screening of an overlapping peptide library of the S protein with COVID-19 patients' convalescent serum. And the peptides were verified by testing with 165 serum samples. P104 has not been reported previously; P82 is contained in peptide S21P2 reported before. The positive reaction rates of epitope peptides S14P5 and S21P2, the two non-RBD region epitopes identified by Poh et al., and P82 and P104 were 77.0%, 73.9%, 61.2% and 30.3%, respectively, for 165 convalescent sera, including 30 asymptomatic patients. Although P104 had the lowest positive rate for total patients (30.3%), it exhibited slight advantage for detection of asymptomatic infections (36.7%). Combination of epitopes significantly improved the positive reaction rate. Among all combination patterns, (S14P5 + S21P2 + P104) pattern exhibited the highest positive reaction rate for all patients (92.7%), as well as for asymptomatic infections (86.7%), confirming the feasibility of P104 as supplementary antigen for serological detection. In addition, we analyzed the correlation between epitopes with neutralizing antibody, but only S14P5 had a medium positive correlation with neutralizing antibody titre (rs = 0.510, P < 0.01). CONCLUSION: Our research proved that epitopes on non-RBD region are of value in serological detection especially when combination more than one epitope, thus providing serological reaction information about the four epitopes, which has valuable references for their usage.

Foveal scanning based on an optical-phases array.

We utilize the space-variant structure of the human fovea as a basis for a novel, to the best of our knowledge, foveal approach based on optical-phases array (OPA). This approach can be used to solve issues in 3D imaging and achieve a large field of view and high resolution with real-time application. A foveal scanning model based on the OPA is established. Simulations and experiments are performed to verify the models and illustrate the advantages of foveal scanning compared with traditional raster scanning. Simulations agree well with the theory, and the foveal approach has higher efficiency than traditional raster scanning. These results can serve as a reference for developing biomimetic sensors that mimic the human eye.

[Prokaryotic Expression and Immunogenicity Analysis of a Fusion Protein Containing Cell Epitopes of Mycobacterium tuberculosis Rv2660c, Rv2460c, Rv3875 and Rv3804c Genes].

OBJECTIVE: To analyse the immunogenicity of a fusion protein containing cell epitopes of Mycobacterium tuberculosis genes Rv2660c, Rv2460c, Rv3875 and Rv3804, and to evaluate the feasibility of using it as a novel target antigen for developing multi-stage TB vaccines. METHODS: Cell epitopes of Rv2660c, Rv2460c, Rv3875 and Rv3804c were fused in series to form a new antigen gene (named msv). Then msv was cloned into the prokaryotic expression vector pEASY-Blunt E1. The fusion protein msv was expressed by pEASY-Blunt E1 under the induction of isopropyl-ß-d-thiogalactoside (IPTG). Purified the protein by affinity chromatography and identified the protein by SDS-PAGE and Western blot. To evaluate the immunogenicity of the protein, the mice were immunized with the purified fusion protein, and the titer of the antibody in mice serum was evaluated by ELISA. Besides, splenocytes of immunized mice were separated and splenocytes proliferation was determined under the stimulation of the protein. RESULTS: The prokaryotic expression plasmid carrying msv gene was constructed successfully and msv protein could be expressed by the plasmid under the induction of IPTG. SDS-PAGE and Western blot results confirmed that a purified protein (relative molecular mass was 41.3×103) was obtained. ELISA result indicated that the titer of the antibody in msv immunized mice serum was about 1:81 920.The spleen lymphocyte proliferation assay showed that after immunization with msv protein, significant proliferation of antigen-sensitized lymphocytes was observed. CONCLUSIONS: The fusion protein msv was successfully expressed and purified, which can induce humoral and cellular immunity in mice. It may be used as an antigen component for the development of TB vaccine in the future.