Operando spectroscopy study of the carbon dioxide electro-reduction by iron species on nitrogen-doped carbon

The carbon–carbon coupling via electrochemical reduction of carbon dioxide represents the biggest challenge for using this route as platform for chemicals synthesis. Here we show that nanostructured iron (III) oxyhydroxide on nitrogen-doped carbon enables high Faraday efficiency (97.4%) and selectivity to acetic acid (61%) at very-low potential (−0.5 V vs silver/silver chloride). Using a combination of electron microscopy, operando X-ray spectroscopy techniques and density functional theory simulations, we correlate the activity to acetic acid at this potential to the formation of nitrogen-coordinated iron (II) sites as single atoms or polyatomic species at the interface between iron oxyhydroxide and the nitrogen-doped carbon. The evolution of hydrogen is correlated to the formation of metallic iron and observed as dominant reaction path over iron oxyhydroxide on oxygen-doped carbon in the overall range of negative potential investigated, whereas over iron oxyhydroxide on nitrogen-doped carbon it becomes important only at more negative potentials

Toll-like receptor 4 signaling in liver injury and hepatic fibrogenesis

Toll-like receptors (TLRs) are a family of transmembrane pattern recognition receptors (PRR) that play a key role in innate and adaptive immunity by recognizing structural components unique to bacteria, fungi and viruses. TLR4 is the most studied of the TLRs, and its primary exogenous ligand is lipopolysaccharide, a component of Gram-negative bacterial walls. In the absence of exogenous microbes, endogenous ligands including damage-associated molecular pattern molecules from damaged matrix and injured cells can also activate TLR4 signaling. In humans, single nucleotide polymorphisms of the TLR4 gene have an effect on its signal transduction and on associated risks of specific diseases, including cirrhosis. In liver, TLR4 is expressed by all parenchymal and non-parenchymal cell types, and contributes to tissue damage caused by a variety of etiologies. Intact TLR4 signaling was identified in hepatic stellate cells (HSCs), the major fibrogenic cell type in injured liver, and mediates key responses including an inflammatory phenotype, fibrogenesis and anti-apoptotic properties. Further clarification of the function and endogenous ligands of TLR4 signaling in HSCs and other liver cells could uncover novel mechanisms of fibrogenesis and facilitate the development of therapeutic strategies

A highly reactive precursor in the iron sulfide system

Iron sulfur (Fe–S) phases have been implicated in the emergence of life on early Earth due to their catalytic role in the synthesis of prebiotic molecules. Similarly, Fe–S phases are currently of high interest in the development of green catalysts and energy storage. Here we report the synthesis and structure of a nanoparticulate phase (FeSnano) that is a necessary solid-phase precursor to the conventionally assumed initial precipitate in the iron sulfide system, mackinawite. The structure of FeSnano contains tetrahedral iron, which is compensated by monosulfide and polysulfide sulfur species. These together dramatically affect the stability and enhance the reactivity of FeSnano

An upwind kinetic flux vector splitting method for the euler equations on unstructured grids

This report describes the implementation, results and experiences gained in implementing an upwind kinetic flux vector splitting (KFVS) algorithm, developed by Deshpande and Mandal (1-7) on unstructured meshes constructed using the Delaunay triangulation (8,13,15)

The numerical simulation of invisid compressible aeronautical flows

In this collaborative work, an unstructured grid generation technique, based upon the Delaunay triangulation, has been combined with an upwind kinetic flux vector splitting high resolution flow algorithm to simulate inviscid compressible flows for aeronautical applications

Investigating the influence of aquifer heterogeneity on the potential for thermal free convection in the Yarragadee Aquifer, Western Australia

The potential for thermal convection in aquifers is strongly influenced by permeability. Permeability is highly heterogeneous within aquifers, and spatial distributions of permeability are rarely well constrained by measurements, making it difficult to determine the potential for thermal convection in a given aquifer. In this study, this difficulty is overcome through the use of a stratigraphic forward model (SFM). The SFM simulates the processes of deposition, burial and compaction of the aquifer, yielding a geologically plausible permeability field that is conditioned through measured permeability-porosity relationships. The aim of this study is to determine the influence of aquifer heterogeneity on the potential for thermal convection in the Yarragadee Aquifer, Western Australia. Permeability distributions from the SFM of the Yarragadee Aquifer are analysed through calculation of the thermal Rayleigh number (a stability criterion) from vertically averaged permeability, and numerical hydrothermal simulations with permeability distributions taken from the SFM. Results from the numerical simulations demonstrate that thermal convection can occur with the inclusion of geologically informed heterogeneity. These findings are supported by Rayleigh number calculations that indicate that convection is most likely to occur on the eastern side of the aquifer where it is thick and has high average permeability