The oxidation of neat methane (CH4) and CH4 doped with NO2 or NO in argon has been investigated in a jet-stirred reactor at 107 kPa, temperatures between 650 and 1200 K, with a fixed residence time ...of 1.5 s, and for different equivalence ratios (Φ), ranging from fuel-lean to fuel-rich conditions. Four different diagnostics have been used: gas chromatography (GC), chemiluminescence NOx analyzer, continuous wave cavity ring-down spectroscopy (cw-CRDS) and Fourier transform infrared spectroscopy (FTIR). In the case of the oxidation of neat methane, the onset temperature for CH4 oxidation was above 1025 K, while it is shifted to 825 K with the addition of NO2 or NO, independently of equivalence ratio, indicating that the addition of NO2 or NO highly promotes CH4 oxidation. The consumption rate of CH4 exhibits a similar trend with the presence of both NO2 and NO. The amount of produced HCN has been quantified and a search for HONO and CH3NO2 species has been attempted. A detailed kinetic mechanism, derived from POLIMI kinetic framework, has been used to interpret the experimental data with a good agreement between experimental data and model predictions. Reaction rate and sensitivity analysis have been conducted to illustrate the kinetic regimes. The fact that the addition of NO or NO2 seems to have similar effects on promoting CH4 oxidation can be explained by the fact that both species are involved in a reaction cycle interchanging them and whose result is 2CH3 + O2 = 2CH2O + 2H. Additionally, the direct participation of NO2 in the NO2 + CH2O = HONO + HCO reaction has a notable accelerating effect on methane oxidation.
NiO/Al
2O
3 catalyst precursors were prepared by simultaneous precipitation, in a Ni:Al molar ratio of 3:1, promoted with Mo oxide (0.05, 0.5, 1.0 and 2.0
wt%). The solids were characterized by ...adsorption of N
2, XRD, TPR, Raman spectroscopy and XPS, then activated by H
2 reduction and tested for the catalytic activity in methane steam reforming.
The characterization results showed the presence of NiO and Ni
2AlO
4 in the bulk and Ni
2AlO
4 and/or Ni
2O
3 and
MoO
4
-
2
at the surface of the samples.
In the catalytic tests, high stability was observed with a reaction feed of 4:1 steam/methane. However, at a steam/methane ratio of 2:1, only the catalyst with 0.05% Mo remained stable throughout the 500
min of the test.
The addition of Mo to Ni catalysts may have a synergistic effect, probably as a result of electron transfer from the molybdenum to the nickel, increasing the electron density of the catalytic site and hence the catalytic activity.
PEM fuel cells seem to be the most affordable and commercially viable hydrogen-based cells, the biggest challenge being to obtain CO-free H2 (<100 ppm) as the fuel. In this study, the use of CuO–CeO2 ...catalysts in preferential oxidation of CO to obtain CO-free H2 (PROX reaction) was investigated. Ce1−xCuxO2 catalysts, with x (mol%) = 0, 0.01, 0.03, 0.05 and 0.10, were synthesized in one-step by the polymeric precursor method, to obtain a very fine dispersion and strong metal-support interaction, to favor active copper species and a preference for the PROX reaction. The results obtained from catalyzed reactions and characterization of the catalysts by XRD, Rietveld refinement, BET surface area, UV–Vis and TPR, suggest that this one-step synthesis method gives rise to catalysts with copper species selective for the PROX reaction, which reaches a maximum rate on Ce0.97Cu0.03O2 catalyst.
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► Synthesis of CuO/CeO2 catalysts by the one-step polymeric precursor method. ► 100% CO conversion on Ce0.97Cu0.03O2 catalyst. ► Monomeric surface and dipolar Cu2+ are responsible for the improved CO conversion.
Kinetoplastids are infamous parasites that include trypanosomes and Leishmania species. Here, we developed an anti-Leishmania nano-drug using ultra-small functional maghemite (γ-Fe2O3) nanoparticles ...(NPs) that were surface-doped by CeLn3/4+ to enable effective binding of the polycationic polyethylenebyimine (PEI) polymer by coordinative chemistry. This resulting nano-drug is cytolytic in-vitro to both Trypanosoma brucei parasites, the causative agent of sleeping sickness, as well as to three Leishmania species. The nano-drug induces the rupture of the single lysosome present in these parasites attributed to the PEI, leading to cytolysis. To evaluate the efficacy of a “cream-based” version of the nano-drug, which was termed “Nano-Leish-IL” for topical treatment of cutaneous leishmaniasis (CL), we developed a rapid screening method utilizing T. brucei parasites involved in social motility and demonstrated that functional NPs arrested the migration of the parasites. This assay presents a surrogate system to rapidly examine the efficacy of “cream-based” drugs in topical preparations against leishmaniasis, and possibly other dermal infectious diseases. The resulting Nano-Leish-IL topical preparation eliminated L. major infection in mice. Thus, this study presents a novel efficient nano-drug targeting the single lysosome of kinetoplastid parasites.
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Nickel catalysts were prepared on single-oxide supports of Al2O3, CeO2, MgO and ZrO2 by impregnation of the oxide with a solution of Ni(NO3)2 in methanol. The catalysts were characterized by N2 ...physisorption (BET method), TPR, XRD, SEM and Raman spectroscopy and tested in dry reforming of ethanol (DRE). It was observed that the interaction with the support and Ni reducibility depended on the support used. According to TPR results, NiO species supported on CeO2 and Al2O3 were the easiest to reduce. Possibly, this behavior combined to redox properties of CeO2 inhibited side undesirable reactions and contributed to the higher selectivity for H2 on the NiCe catalyst. The catalytic test at 750°C on NiCe showed better H2 selectivity than the test at 700°C, suggesting that the higher temperature enhanced CO2 conversion and hindered carbon deposition in dry reforming of ethanol reactions.
•Ni catalysts were prepared by impregnation using methanol as solvent.•The interaction with the support and Ni reducibility depended on the support used.•NiO species supported on CeO2 were the easiest to reduce.•The NiCe catalyst showed the highest selectivity for hydrogen production.•Filamentous carbon species were observed in Raman spectra and SEM image of NiCe.
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▶ The catalyst precursors consist of a mixture of oxides, with the nickel in the form of NiO strongly interacting with the support Mg/Al. ▶ The catalysts consist of Ni
0 species ...dispersed on a solid solution of (Ni,Mg)AlO support. ▶ The addition of Ce or La resulted in better H
2 production per mol of ethanol in the feed. ▶ The better performance of the CeNi catalyst can be related to the low interaction of the Ce species with the support.
Catalyst precursors composed of Ni/Mg/Al oxides with added La and Ce were tested in ethanol steam reforming (ESR) reactions. La and Ce were added by anion-exchange. The oxides were characterized by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) analysis. The catalyst precursors consist of a mixture of oxides, with the nickel in the form of NiO strongly interacting with the support Mg/Al. The XPS analysis showed a lanthanum–support interaction, but no interaction of Ce species with the support. The reaction data obtained with the active catalysts showed that the addition of Ce and La resulted in better H
2 production at 550
°C. The CeNi catalyst provided the higher ethanol conversion, with lower acetaldehyde production, possibly due to a favoring of water adsorption on the weakly interacting clusters of CeO
2 on the surface.
We propose that MuSC-derived myoblasts in PAD have transcriptomic differences that can highlight underlying causes of ischemia-induced myopathy.
Differentiation capacity among perfused and ischemic ...human myoblasts was compared. Following next generation sequencing of mRNA, Ingenuity Pathway Analysis (IPA) was performed for canonical pathway enrichment. Live cell imaging and immunofluorescence were performed to determine myocyte fusion index and protein expression based on insights from IPA, specifically concerning cell cycle regulators including cell-division cycle protein 2 (CDC2) and polo-like kinase 1 (PLK1).
Ischemic myoblasts formed attenuated myotubes indicative of reduced fusion. Additionally, myoblasts from ischemic segments showed significant differences in canonical pathways associated with PLK1 (upregulated) and G2/M DNA damage checkpoint regulation (downregulated). PLK1 inhibition with BI2536 did not affect cell viability in any group over 24 h but deterred fusion more significantly in PAD myoblasts. Furthermore, PLK1 inhibition reduced the expression of checkpoint protein CDC2 in perfused but not ischemic cells.
Differentiating myoblasts derived from ischemic muscle have significant differences in gene expression including those essential to DNA-damage checkpoint regulation and cell cycle progress. DNA-damage checkpoint dysregulation may contribute to myopathy in PAD.
•1.Myoblasts from skeletal muscle in peripheral arterial disease (PAD) proliferate normally ex vivo.•2.Despite viability and higher proliferative capacity, myoblast differentiation is significantly deterred in PAD with potential functional consequences.•Differentially expressed genetic analysis demonstrate marked upregulation of polo-like kinase (PLK1) associated mitotic pathways and concomitant downregulation in DNA checkpoint pathways in PAD.•Inhibiting PLK1 deterred differentiation significantly in PAD.
Alumina-supported and non-supported molybdenum carbides were prepared from trioxide of molybdenum for methane steam reforming. The transition metal carbides are formed in a process of carburization, ...substituting the oxygen by carbon atoms in the crystal lattice of these metals. The samples were carburized at 700
°C, 800
°C and 900
°C. The characterization of solids was performed by elemental analysis, X-ray diffraction, N
2 adsorption and temperature-programmed surface reaction. Catalytic tests were carried through in a fixed-bed quartz micro-reactor and analyzed with on-line gas chromatography. All the catalysts show stability during the reaction. The most actives samples were those carburized at 700
°C, both among the supported and non-supported catalysts. These solids had largest surface areas and the lowest free carbon deposition on the surface, leading to higher H
2 yields than catalysts treated at 800
°C or 900
°C.
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