Electrochemical water splitting is one of the most promising approaches for sustainable energy conversion and storage toward a future hydrogen society. This demands durable and affordable ...electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this study, we report the preparation of uniform Ni-P-O, Ni-S-O, and Ni-S-P-O electrocatalytic films on nickel foam (NF) substrates
via
flow cell-assisted electrodeposition. Remarkably, electrodeposition onto 12 cm
2
substrates was optimized by strategically varying critical parameters. The high quality and reproducibility of the materials is attributed to the use of a 3D-printed flow cell with a tailored design. Then, the as-fabricated electrodes were tested for overall water splitting in the same flow cell under alkaline conditions. The best-performing sample, NiSP/NF, required relatively low overpotentials of 93 mV for the HER and 259 mV for the OER to produce a current density of 10 mA cm
−2
. Importantly, the electrodeposited films underwent oxidation into amorphous nickel (oxy)hydroxides and oxidized S and P species, improving both HER and OER performance. The superior electrocatalytic performance of the Ni-S-P-O films originates from the unique reconstruction process during the HER/OER. Furthermore, the overall water splitting test using the NiSP/NF couple required a low cell voltage of only 1.85 V to deliver a current density of 100 mA cm
−2
. Overall, we demonstrate that high-quality electrocatalysts can be obtained using a simple and reproducible electrodeposition method in a robust 3D-printed flow cell.
A reproducible and efficient electrodeposition method in a 3D-printed flow cell is used to synthesize high-quality Ni-S-P-O films on nickel foam for overall water splitting.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected 78 million individuals and is responsible for over 1.7 million deaths to date. Infection is associated with the development ...of variable levels of antibodies with neutralizing activity, which can protect against infection in animal models
. Antibody levels decrease with time, but, to our knowledge, the nature and quality of the memory B cells that would be required to produce antibodies upon reinfection has not been examined. Here we report on the humoral memory response in a cohort of 87 individuals assessed at 1.3 and 6.2 months after infection with SARS-CoV-2. We find that titres of IgM and IgG antibodies against the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 decrease significantly over this time period, with IgA being less affected. Concurrently, neutralizing activity in plasma decreases by fivefold in pseudotype virus assays. By contrast, the number of RBD-specific memory B cells remains unchanged at 6.2 months after infection. Memory B cells display clonal turnover after 6.2 months, and the antibodies that they express have greater somatic hypermutation, resistance to RBD mutations and increased potency, indicative of continued evolution of the humoral response. Immunofluorescence and PCR analyses of intestinal biopsies obtained from asymptomatic individuals at 4 months after the onset of coronavirus disease 2019 (COVID-19) revealed the persistence of SARS-CoV-2 nucleic acids and immunoreactivity in the small bowel of 7 out of 14 individuals. We conclude that the memory B cell response to SARS-CoV-2 evolves between 1.3 and 6.2 months after infection in a manner that is consistent with antigen persistence.
Many pathogens, such as Pseudomonas aeruginosa and Escherichia coli bacteria can easily attach to surfaces and form stable biofilms. The formation of such biofilms in surfaces presents a problem in ...environmental, biomedical, and industrial processes, among many others. Aiming to provide a plausible solution to this issue, the anionic and hydrophobic peptide Maximin H5 C-terminally deaminated isoform (MH5C) has been modified with a cysteine in the C-terminal (MH5C-Cys) and coupled to polyethylene glycol (PEG) polymers of varying sizes (i.e., 2 kDa and 5 kDa) to serve as a surface protective coating. Briefly, the MH5C-Cys was bioconjugated to PEG and purified by size exclusion chromatography while the reaction was confirmed via SDS-PAGE and MALDI ToF. Moreover, the preventive antimicrobial activity of the MH5C-Cys-PEG conjugates was performed via the growth curves method, showing inhibition of bacterial growth after 24 h. The efficacy of these peptide–polymer conjugates was extensively characterized via scanning electron microscopy (SEM), minimum inhibition concentration (MIC), minimum biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC) assays to evaluate their ability to eradicate and prevent the biofilms. Interestingly, this work demonstrated a critical PEG polymer weight of 5 kDa as ideal when coupled to the peptide to achieve inhibition and eradication of the biofilm formation in both bacteria strains. According to the MICs (40 μM) and MBICs (300 μM), we can conclude that this conjugate (MH5C-Cys-5 kDa) has an action that prevents/inhibits the formation of biofilms and the eradication of biofilms (MBEC 500 μM). In contrast, the MH5C-Cys peptide with PEG polymer of 2 kDa did not show inhibition or eradication of the biofilms.
Here we report on the antibody and memory B cell responses of a cohort of 20 volunteers who received the Moderna (mRNA-1273) or Pfizer-BioNTech (BNT162b2) vaccine against SARS-CoV-2
. Eight weeks ...after the second injection of vaccine, volunteers showed high levels of IgM and IgG anti-SARS-CoV-2 spike protein (S) and receptor-binding-domain (RBD) binding titre. Moreover, the plasma neutralizing activity and relative numbers of RBD-specific memory B cells of vaccinated volunteers were equivalent to those of individuals who had recovered from natural infection
. However, activity against SARS-CoV-2 variants that encode E484K-, N501Y- or K417N/E484K/N501-mutant S was reduced by a small-but significant-margin. The monoclonal antibodies elicited by the vaccines potently neutralize SARS-CoV-2, and target a number of different RBD epitopes in common with monoclonal antibodies isolated from infected donors
. However, neutralization by 14 of the 17 most-potent monoclonal antibodies that we tested was reduced or abolished by the K417N, E484K or N501Y mutation. Notably, these mutations were selected when we cultured recombinant vesicular stomatitis virus expressing SARS-CoV-2 S in the presence of the monoclonal antibodies elicited by the vaccines. Together, these results suggest that the monoclonal antibodies in clinical use should be tested against newly arising variants, and that mRNA vaccines may need to be updated periodically to avoid a potential loss of clinical efficacy.
More than one year after its inception, the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains difficult to control despite ...the availability of several working vaccines. Progress in controlling the pandemic is slowed by the emergence of variants that appear to be more transmissible and more resistant to antibodies
. Here we report on a cohort of 63 individuals who have recovered from COVID-19 assessed at 1.3, 6.2 and 12 months after SARS-CoV-2 infection, 41% of whom also received mRNA vaccines
. In the absence of vaccination, antibody reactivity to the receptor binding domain (RBD) of SARS-CoV-2, neutralizing activity and the number of RBD-specific memory B cells remain relatively stable between 6 and 12 months after infection. Vaccination increases all components of the humoral response and, as expected, results in serum neutralizing activities against variants of concern similar to or greater than the neutralizing activity against the original Wuhan Hu-1 strain achieved by vaccination of naive individuals
. The mechanism underlying these broad-based responses involves ongoing antibody somatic mutation, memory B cell clonal turnover and development of monoclonal antibodies that are exceptionally resistant to SARS-CoV-2 RBD mutations, including those found in the variants of concern
. In addition, B cell clones expressing broad and potent antibodies are selectively retained in the repertoire over time and expand markedly after vaccination. The data suggest that immunity in convalescent individuals will be very long lasting and that convalescent individuals who receive available mRNA vaccines will produce antibodies and memory B cells that should be protective against circulating SARS-CoV-2 variants.
The serine protease inhibitors (SPIs) are widely distributed in living organisms like bacteria, fungi, plants, and humans. The main function of SPIs as protease enzymes is to regulate the proteolytic ...activity. In plants, most of the studies of SPIs have been focused on their physiological role. The initial studies carried out in plants showed that SPIs participate in the regulation of endogenous proteolytic processes, as the regulation of proteases in seeds. Besides, it was observed that SPIs also participate in the regulation of cell death during plant development and senescence. On the other hand, plant SPIs have an important role in plant defense against pests and phytopathogenic microorganisms. In the last 20 years, several transgenic plants over-expressing SPIs have been produced and tested in order to achieve the increase of the resistance against pathogenic insects. Finally, in molecular farming, SPIs have been employed to minimize the proteolysis of recombinant proteins expressed in plants. The present review discusses the potential biotechnological applications of plant SPIs in the agriculture field.
•Bismuth photocatalysts exhibited an excellent oxidizing activity for polypropylene.•The polypropylene oxidation degree increase as a function of catalyst load.•Organic compounds with commercial ...value can be obtained from polypropylene.•2,3 butane-dione was the main degrading product from polypropylene oxidation.
Every year millions of tons of polymeric waste are discarded by human activities due to its low production cost; the landfills are littered with plastic waste without any recycling value. This class of garbage exhibits a very low degradation rate under environmental conditions, occupying a lot of space in landfills for a long time, which is costly for society and harmful to environment. Photocatalysis has become a quite interesting tool to oxidize organic pollutants as dyes, drugs, and some polymers, representing a potential alternative for reducing the environmental pollution. In this work, we report an ecofriendly method for polypropylene (PP) degradation by catalytic bismuth nanoparticles (Bi2O3 or BiFeO3) assisted by ionizing radiation. The effect of catalyst load and applied radiation dose on photo-degradation rate were studied. High oxidation efficiencies were detected even at both low catalyst load nd irradiation dose. Oxidized propylene was detected by infrared spectroscopy (FTIR-ATR), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (SEM-EDS). All those instrumental techniques confirmed the successful oxidation of PP in few hours of reaction and 1% weight of the catalyst. 2,3 butane-dione, 4-hydroxy-4-methyl pentane-2-one, and ethyl-9-acetoxynonanoate were the main degradation products identified mainly by nuclear magnetic resonance (NMR 1H, 13C).
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