Interface Engineering-Modulated Nanoscale Bimetallic CoFe-MIL-88A In-Situ-Grown on 2D V₂CT_<i>x</i> MXene for Electrocatalytic Nitrogen Reduction

The electrochemical nitrogen reduction reaction (eNRR) provides a sustainable green development route for the nitrogen-neutral cycle. In this work, bimetallic CoFe-MIL-88A with two active sites (Fe, Co) were immobilized on a 2D V2CTx MXene surface by in situ growth method to achieve the purpose of the control interface. A large number of heterostructures are formed between small CoFe-MIL-88A and V2CTx, which regulate the electron transfer between the catalyst interfaces. The adsorption and activation of nitrogen on the active sites were enhanced, and the NRR reaction kinetics was accelerated. CoFe-MIL-88A is tightly arranged on V2CTx, which makes CoFe-MIL-88A/V2CTx have better hydrophobicity and can significantly inhibit the hydrogen evolution reaction. The synergistic effect of multicatalytic active sites and multi-interface structure of CoFe-MIL-88A/V2CTx MXene is propitious to nitrogen efficiently and stably to convert into ammonia under environmental conditions with superior selectivity and good catalytic activity. The NH3 yield rate is 29.47 μg h–1 mgcat–1 at −0.3 V vs RHE, and the Faradaic efficiency (FE) is 28.86% at −0.1 V vs RHE. The catalytic mechanism was verified to conform to the distal pathway. This work will provide a new way to develop an MXene-based electrocatalyst for eNRR

Additional file 2: Figure S2. of Analyzing pathogenic (double-stranded (ds) DNA-specific) plasma cells via immunofluorescence microscopy

Correlation between dsDNA-specific plasma cells numbers in spleen and bone marrow with the anti-dsDNA antibody titer in the serum. (JPEG 1553 kb

Effects of short-term depletion treatments on plasma cell numbers in bone marrow and spleen.

<p><b>(A)</b> Representative FACS histogram of bone marrow and splenic CD138⁺ intracellular κ⁺ BrdU⁺ short-lived plasma cells (SLPCs), and CD138⁺ intracellular κ⁺ BrdU^- long-lived plasma cells (LLPCs) from each treatment group. Percentage of remaining cell numbers relative to the control mean of (<b>B)</b> bone marrow and (<b>C)</b> splenic CD138⁺ intracellular κ⁺ total plasma cells (PCs), SLPCs, and LLPCs in mice treated with PBS, anti-CD20, anti-CD20 plus integrin-blocking antibodies (Int; anti-LFA1 and anti-VLA4 antibodies), anti-CD20 plus bortezomib (Bz) and anti-CD20 plus Int and Bz. Total PCs, SLPCs and LLPCs were enumerated by flow cytometry 7 days after the start of treatment (<i>n</i> = 5–6 mice per each group). Values are mean±SEM; ns, non-significant; P>0.05, *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001, post-hoc test. Abbreviations: Bz, bortezomib; CD20, anti-mouse CD20 antibody; FMO, Fluorescence-minus-one; Int, Integrin blocking antibodies; anti-LFA1 and anti-VLA4 antibodies.</p

Effects of short-term depletion treatments on bone marrow and splenic T cells.

<p>Percentage of remaining CD3⁺ T cells, CD4⁺ T-helper cells, and CD8⁺ T-cytotoxic cells after one week of treatment in ratio to the mean of control in (<b>A)</b> the bone marrow, and (<b>B)</b> spleen. Values are mean±SEM; ns, non-significant, P>0.05, *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001, post-hoc test (<i>n</i> = 5–6 mice per group). Abbreviations: Bz, bortezomib; CD20, anti-mouse CD20 antibody; Int, Integrin blocking antibodies, anti-LFA1 and anti-VLA4 antibodies.</p

B cell depletion (BCD) maintenance therapy after short-term depletion (STD) of B and plasma cells with ant-CD20 and bortezomib improves the disease in NZB/W F1 mice.

<p>Mice (n = 4) were treated with anti-CD20 and bortezomib (STD) alone or continuous B cell depletion without bortezomib (BCD, n = 5) or treated as STD followed by BCD maintenance therapy with anti-CD20 (STD+BCD, n = 4). (<b>A)</b> Serum IgM and IgG anti-dsDNA antibody levels in treated and untreated mice (n = 9), as measured by ELISA. (<b>B)</b> Proteinuria in treated and untreated mice. Statistical differences between treated and untreated mice were analyzed using the post-hoc test (ns, non-significant, P>0.05, *<i>P</i><0.05; **<i>P</i><0.01, ***<i>P</i><0.001). (<b>C)</b> Survival curves for treated and untreated NZB/W F1 mice (Kaplan—Meier log-rank test). Abbreviations: STD, Short-term depletion (anti-CD20 and bortezomib); BCD; B cell depletion (anti-CD20).</p

Effects of short-term depletion treatments on the numbers of different B-cell subsets in bone marrow and spleen.

<p>Percentage of remaining B cell subsets in the bone marrow and spleen in ratio to the mean of control. (<b>A)</b> Bone marrow B-cell subsets identified by flow cytometry: total B cells (BCs) (CD19⁺), bone marrow pro-B cells (CD93⁺CD117⁺), pre-B cells (CD24⁺IgM^-IgD^-), immature B cells (CD24⁺IgM⁺IgD^-), and mature B cells (CD24^-IgM⁺IgD⁺). (<b>B)</b> Splenic B-cell subsets identified by flow cytometry: follicular (FO) B cells (CD23⁺CD21⁺IgM⁺), marginal zone (MZ) B cells (CD23^- CD21⁺IgM⁺), germinal center (GC) B cells (IgD^-GL7⁺), and B1 B cells (CD23^-CD21^-IgM⁺). Values are mean±SEM; ns, non-significant, P>0.05, *<i>P</i><0.05; **<i>P</i><0.01, ***<i>P</i><0.001, post-hoc test (<i>n</i> = 5–6 mice per group). Abbreviations: Bz, bortezomib; CD20, anti-mouse CD20 antibody; Int, Integrin blocking antibodies; anti-LFA1 and anti-VLA4 antibodies.</p