Enhanced Carbon Monoxide Electroreduction to >1 A cm−2 C2+ Products Using Copper Catalysts Dispersed on MgAl Layered Double Hydroxide Nanosheet House-of-Cards Scaffolds

Cu catalysts are most apt for reducing CO₍₂₎ to multi-carbon products in aqueous electrolytes. To enhance the product yield, we can increase the overpotential and the catalyst mass loading. However, these approaches can cause inadequate mass transport of CO₍₂₎ to the catalytic sites, which will then lead to H₂ evolution dominating the product selectivity. Herein, we use a MgAl LDH nanosheet ‘house-of-cards’ scaffold to disperse CuO-derived Cu (OD-Cu). With this support-catalyst design, at −0.7 V_RHE, CO could be reduced to C₂₊ products with a current density (j_C2+) of −1251 mA cm⁻². This is 14× that of the j_C2+ shown by unsupported OD-Cu. The current densities of C₂₊ alcohols and C₂H₄ were also high at −369 and −816 mA cm⁻² respectively. We propose that the porosity of the LDH nanosheet scaffold enhances CO diffusion through the Cu sites. The CO reduction rate can thus be increased, while minimizing H₂ evolution, even when high catalyst loadings and large overpotentials are used.     

Design,synthesis and therapeutic potential of 3-(2-(1<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">d</Emphasis>]imidazol-2-ylthio)acetamido)-<Emphasis Type="Italic">N</Emphasis>-(substituted phenyl)benzamide analogues

Background

The emergence of bacterial resistance is a major public health problem. It is essential to develop and synthesize new therapeutic agents with better activity. The mode of actions of certain newly developed antimicrobial agents, however, exhibited very limited effect in treating life threatening systemic infections. Therefore, the advancement of multi-potent and efficient antimicrobial agents is crucial to overcome the increased multi-drug resistance of bacteria and fungi. Cancer, which remains as one of the primary causes of deaths and is commonly treated by chemotherapeutic agents, is also in need of novel and efficacious agents to treat resistant cases. As such, a sequence of novel substituted benzamides was designed, synthesized and evaluated for their antimicrobial and anticancer activities.

Methodology

All synthesized compounds were characterized by IR, NMR, Mass and elemental analysis followed by in vitro antimicrobial studies against Gram-positive (Staphylococcus aureus), Gram-negative (Salmonella typhi and Klebsiella pneumoniae) bacterial and fungal (Candida albicans and Aspergillus niger) strains by the tube dilution method. The in vitro anticancer evaluation was carried out against the human colorectal carcinoma cell line (HCT116), using the Sulforhodamine B assay.

Results, discussion and conclusion

Compound W6 (MIC_{sa, st, kp}?=?5.19 µM) emerged as a significant antibacterial agent against all tested bacterial strains i.e. Gram-positive (S. aureus), Gram-negative (S. typhi, K. pneumoniae) while compound W1 (MIC_{ca, an}?=?5.08 µM) was most potent against fungal strains (A. niger and C. albicans) and comparable to fluconazole (MIC?=?8.16 µM). The anticancer screening demonstrated that compound W17 (IC₅₀?=?4.12 µM) was most potent amongst the synthesized  compounds and also more potent than the standard drug 5-FU (IC₅₀?=?7.69 µM).

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Fermion zero modes in the presence of non-abelian vortices

The Dirac equation in the presence of non-abelian vortices is investigated . For isospinor fermions coupled to the vortex in the SU(2) Nielsen-Olesen model, there are normalisable well-behaved zero-energy solutions. When the fermions are in the adjoint representation there are no normalisable zero modes. The Z₂ vortex appearing in a SO(10) theory is explicitly constructed and it is shown that the heavy neutrino can be bound to it in a zero-energy state.     

Organic and inorganic nanoparticle hybrids

Viruses are exemplary models in nanoassembly for their regular geometries, well characterized surface properties, and nanoscale dimensions. Armed with versatile tools aimed at site-directed mutagenesis to modify the virion's surface, conjugation chemistry for capsid coupling, and manipulation of nanoparticles, we have demonstrated nanoscale assembly of inorganic carbon nanotubes and quantum dots with engineered viruses to produce an intimate array of hybrid structures.     

N-(acridin-9-yl)arenesulfonamides: Synthesis,quantum chemical studies and crystal structure analysis to establish the tautomeric preferences

The potentiality of the N-(acridin-9-yl)arenesulfonamide moiety as a hybrid pharmacophore due to the distinct pharmacological activities of acridines and aryl/heteroaryl sulfonamides prompts to synthesise N-(acridin-9-yl)arenesulfonamides and study their structural properties. Various N-(acridin-9-yl)arene/heteroarenesulfonamides were obtained through the development of a new methodology adopting the Pd₂(dba)₃-catalyzed CN bond formation strategy for the reaction of 9-chloloroacridine with arene/heteroarenesulfonamides. The 1H and ¹³C NMR spectra suggest these N-(acridin-9-yl)arene/heteroarenesulfonamides to exist solely as the sulfonimide tautomer rather than anticipated sulfonamide form and was confirmed by the single crystal XRD analysis of one of the newly synthesized compounds. The quantum chemical studies rationalized this tautomeric preference revealing that the sulfonimide tautomers are more stable than the sulfonamide tautomers by ?0.67 to ?5.12?kcal/mol in the gas phase. In the solid state, the sulfonimide tautomer is stabilized by intermolecular hydrogen bond between NH?OS and π? π stacking between the acridine rings.     

Phase‐Stable CsPbI3 Nanocrystals: The Reaction Temperature Matters

High temperature colloidal synthesis for obtaining thermal, colloidal and phase‐stable CsPbI₃ nanocrystals with near‐unity quantum yield is reported. While standard perovskite synthesis reactions were carried out at 160 °C (below 200 °C), increase of another ≈100 °C enabled the alkylammonium ions to passivate the surface firmly and prevented the nanocrystals from phase transformation. This did not require any inert atmosphere storage, use of heteroatoms, specially designed ligands, or the ice cooling protocol. Either at high temperature in reaction flask or in the crude mixture or purified dispersed solution; these nanocrystals were observed stable and retained the original emission. Different spectroscopic analyses were carried out and details of the surface binding of alkyl ammonium ligands in place of surface Cs in the crystal lattice were investigated. As CsPbI₃ is one of the most demanding optical materials, bringing stability by proper surface functionalization without use of secondary additives would indeed help in wide spreading of their applications.     

Recalculation of monomer reactivity considering the effect of monomer partitioning in microemulsion

From the copolymerisation data for the microemulsion polymerisation of both partially water soluble monomers ethylacrylate (EA)-methylmethacrylate (MMA) the concentration of the monomer at the polymerisation loci was calculated. While the reported copolymerisation data for the microemulsion copolymerisation of styrene (Sty)-methylacrylate (MA), monomer pair with different solubility and polarity and Sty-butylacrylate (BA), monomer pair with similar solubility and different polarity was used to calculate the monomer concentration at loci. It was inferred from the non-constancy of f^′_A/f_A and f^′_B/f_B ratio that the preferential site of polymerisation might be the emulsifier layer in case of Sty-MA and Sty-BA. While, based on the monomer fraction in the copolymer and the constancy of f^′_A/f_A and f^′_B/f_B it was concluded that microemulsion polymerisation for monomer pair EA-MMA, having similar solubility and polarity, conforms more to bulk polymerisation, where there is no preferential site of polymerisation. The loci concentration rather than feed value was used to recalculate the reactivity at the site of polymerisation. Also the loci concentration was calculated assuming their sum at the polymerisation site equal to unity.     

Connection between commutative algebra and topology

The main aim of this paper is to show how commutative algebra is connected to topology. We give underlying topological idea of some results on completable unimodular rows.     

Observation of an organic-inorganic lattice match during biomimetic growth of (001)-oriented calcite crystals under floating sulfate monolayers

Macromolecular layers rich in amino acids and with some sulfated polysaccharides appear to control oriented calcite growth in living organisms. Calcite crystals nucleating under floating acid monolayers have been found to be unoriented on average. We have now observed directly, using in situ grazing incidence X-ray diffraction, that there is a 1:1 match between the monolayer unit cell and the unit cell of the (001) plane of calcite. Thus, sulfate head groups appear to act as templates for the growth of (001)-oriented calcite crystals, which is the orientation commonly found in biominerals.