Interaction of Cobalt Nanoparticles with Oxygen- and Nitrogen-Functionalized Carbon Nanotubes and Impact on Nitrobenzene Hydrogenation Catalysis

The type and the amount of functional groups on the surface of carbon nanotubes (CNTs) were tuned to improve the activity of supported Co nanoparticles in hydrogenation catalysis. Surface nitrogen species on CNTs significantly promoted the decomposition of the cobalt precursor and the reduction of cobalt oxide, and improved the resistance of metallic Co against oxidation in ambient atmosphere. In the selective hydrogenation of nitrobenzene in the gas phase, Co supported on CNTs with the highest surface nitrogen content showed the highest activity, which is ascribed to the higher reducibility and the lower oxidation state of the Co nanoparticles under reaction conditions. For Co nanoparticles supported on CNTs with a smaller amount of surface nitrogen groups, a repeated reduction at 350 °C was essential to achieve a comparable high catalytic activity reaching 90% conversion at 250 °C, pointing to the importance of nitrogen species for the supported Co nanoparticles in nitrobenzene hydrogenation

Control of Phase Coexistence in Calcium Tantalate Composite Photocatalysts for Highly Efficient Hydrogen Production

Design and fabrication of semiconductor based composite photocatalysts with matching band structure is an important strategy to improve charge separation of photogenerated electron–hole pairs for photocatalytic hydrogen production. In our study, by aid of the simple and cost-effective molten salts method, a series of phase-controlled and composition-tuned calcium tantalate composite photocatalysts has been prepared by adjusting the initial atomic ratio of Ta/Ca precursors. We demonstrate the strong correlation between the photocatalytic activities of calcium tantalate composite photocatalysts for hydrogen evolution and respective phase compositions. Without any cocatalysts, these composites with the optimized phase composition of cubic α-CaTa₂O₆/hexagonal Ca₂Ta₂O₇, cubic CaTa₂O₆/hexagonal Ca₂Ta₂O₇/orthorhombic β-CaTa₂O₆, or cubic α-CaTa₂O₆/orthorhombic β-CaTa₂O₆ showed very high photocatalytic H₂ production activities in the presence of methanol. It is attributed mainly to a significantly improved photoexcited charge carrier separation via the junctions and interfaces in the composites. Further by in situ photodeposition of noble metal nanoparticles (Pt or Rh) as cocatalysts the photocatalytic activity of these composites was greatly promoted for H₂ production. The study on convenient fabrication of phase-coexisting composite photocatalysts with matching band structure for improving the photocatalytic hydrogen production sheds light on developing efficient composite photocatalyst as a means for conversion of solar energy to chemical energy

Anti-CD70-IFN-γ immunocytokines display species-specific antiviral activity.

<p>Murine (RenCa) or human (Caki-1) RCC cells were pre-treated for 16 h with anti-CD70 immunocytokines bearing either murine (m) or human (h) IFN-γ (‘Anti-CD70 fusion’, 50 ng/ml). As controls, parallel populations of these cells were pre-treated for 16 h with recombinant murine or human IFN-γ (‘Native’, 10 ng/ml), or with unfused anti-CD70 antibody (50 ng/ml). Following pre-treatment, cells were infected with VSV-GFP (MOI = 5 for RenCa, 0.05 for Caki-1). (A) Infected cells were photographed by brightfield (for demonstration of cytopathic effect) or by fluorescence (to show viral replication) microscopy 20 h post-infection. (B) Viability of cells treated as above was determined 20 h post-infection. (C) VSV progeny yield from supernatants of infected cells was determined by standard plaque assay 20 h post-infection. Error bars represent mean +/− S.D, n = 3.</p

Anti-CD70-IFN-γ immunocytokines are cytotoxic to RCC cell lines in the presence of bortezomib.

<p>RCC cell lines RenCa (A) or Caki-1 (B) were treated either with unfused anti-CD70 antibody (‘Anti-CD70’), with recombinant, native human or murine IFN-γ (‘Native’), or with human or murine IFN-γ immunocytokines (‘Anti-CD70 fusion’) for 72 h in the presence of their MTD of bortezomib (black bars). As controls, these cells were also treated with each agent singly (grey bars). In conditions requiring bortezomib co-treatment, bortezomib was added to cells 1 h before IFN-γ.</p

Generation and purification of mIFN-γ and hIFN-γ immunocytokines targeting CD70.

<p>(A) Two plasmids – pMAZ-IgH and pMAZ-IgL – were used as backbones to construct and express anti-CD70 immunocytokines bearing either murine (m) or human (h) IFN-γ. pMAZ-IgH expresses the anti-CD70 heavy chain separated from murine or human IFN-γ by a flexible (Gly)₄-Ser linker. pMAZ-IgL encodes the anti-CD70 light chain. For details of construction, expression and purification, please see the Materials and Methods section. (B) Coomassie Blue-stained SDS-PAGE gel of mIFN-γ-anti-CD70 immunocytokine (lane 1), and hIFN-γ-anti-CD70 immunocytokine (lane 2) purified from supernatants of 293T cells after transfection with the plasmids described in A.</p

Anti-CD70-IFN-γ immunocytokines bind human CD70.

<p>(A) 293T cells were transfected with an expression vector encoding Myc-tagged human CD70 (‘CD70’), or with an empty vector (‘Vec’). 24 h post-transfection, cells were examined for CD70 expression in lysates by anti-Myc immunoblotting (inset, top panel; β-actin loading control, bottom panel), or on the cell surface by FACS staining with a FITC-conjugated anti-CD70 monoclonal antibody. (B) 293T cells were transfected as in A with either an empty vector (‘Vec’) or an expression vector encoding Myc-tagged CD70 (‘CD70’). 24 h post-transfection, cells were incubated with either Rituximab as an isotype control human IgG1 antibody (‘Isotype Control’, left panel), or with immunocytokines bearing either murine (m) or human (h) IFN-γ (‘Anti-CD70 fusion’), and, following labeling with FITC-conjugated anti-human IgG secondary antibodies, analyzed by FACS for CD70 expression. (C) The ATCC-derived RCC cell lines 786-O, 769-P, Caki-1, and ACHN were incubated with either an isotype control human IgG1 antibody (Rituximab, dashed line), anti-CD70-mIFN-γ immunocytokine (thin solid line), or anti-CD70-hIFN-γ immunocytokine (thick solid line), followed by labeling with FITC-conjugated anti-human IgG secondary antibodies and detection of fluorescence by FACS. All four ATCC cell lines are robustly and specifically stained by both anti-CD70 IFN-γ immunocytokines.</p

Anti-CD70-IFN-γ immunocytokines exert RIP1-dependent necrotic activity on RCC cell lines.

<p>(A) RenCa, Caki-1, 786-O, or HRC63 cells were co-treated with bortezomib (MTD) and, respectively, murine (RenCa) or human (Caki-1, 786-O, and HRC63) IFN-γ immunocytokines (‘Anti-CD70 fusion’, 50 ng/ml) in the presence or absence of 50 μM RIP1 kinase inhibitor Nec-1 for 72–84 h. The MTD of bortezomib for 786-0 and HRC63 cells was 4 ng/ml and 2 ng/ml, respectively. Cell viability was determined by Trypan Blue exclusion analysis. Error bars represent mean +/− S.D; n = 3. (B) RenCa, Caki-1, 786-O, or HRC63 cells pre-treated without (-Nec-1) or with (+Nec-1) for 1h, before co-treatment with IFN-γ immunocytokines and bortezomib as in (A), were photographed 72 h post-treatment.</p

Experimental and Theoretical Understanding of Nitrogen-Doping-Induced Strong Metal–Support Interactions in Pd/TiO₂ Catalysts for Nitrobenzene Hydrogenation

By doping the TiO₂ support with nitrogen, strong metal–support interactions (SMSI) in Pd/TiO₂ catalysts can be tailored to obtain high-performance supported Pd nanoparticles (NPs) in nitrobenzene (NB) hydrogenation catalysis. According to the comparative studies by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and diffuse reflectance CO FTIR (CO–DRIFTS), N-doping induced a structural promoting effect, which is beneficial for the dispersion of Pd species on TiO₂. High-angle annular dark-field scanning transmission electron microscopy study of Pd on N-doped TiO₂ confirmed a predominant presence of sub-2 nm Pd NPs, which are stable under the applied hydrogenation conditions. XPS and CO–DRIFTS revealed the formation of strongly coupled Pd–N species in Pd/TiO₂ with N-doped TiO₂ as support. Density functional theory (DFT) calculations over model systems with Pd_<i>n</i> (<i>n</i> = 1, 5, or 10) clusters deposited on TiO₂(101) surface were performed to verify and supplement the experimental observations. In hydrogenation catalysis using NB as a model molecule, Pd NPs on N-doped TiO₂ outperformed those on N-free TiO₂ in terms of both catalytic activity and stability, which can be attributed to the presence of highly dispersed Pd NPs providing more active sites, and to the formation of Pd–N species favoring the dissociative adsorption of the reactant NB and the easier desorption of the product aniline