Biocompatible curcumin coupled nanofibrous membrane for pathogens sterilization and isolation.

Airborne transmission of pathogens is the most probable cause for the spread of respiratory diseases, which can be intercepted by personal protective equipment such as masks. In this study, an efficient antiviral personal protective filter was fabricated by coupling the biocompatible curcumin (CCM) with nanofibrous polytetrafluoroethylene (PTFE) membrane. The CCM extracted from plants was first dissolved in acidified ethanol at a certain pH and temperature to optimize its loading concentration, antiviral activation, and binding forces on the polyethylene terephthalate (PET) support to form a pre-filtration layer at the front section of the filter. Ultrathin PTFE membrane was then fabricated on the antibacterial-antiviral PET support (A-A PET) by controllable heating lamination. This functional layer of the filter exhibits good gas permeance (3423.6 m3/(m2·h·kPa)) and ultrafine particles rejection rate (>98.79%). Moreover, the obtained A-A filter exhibit a high antibacterial rate against a variety of bacteria (E. coli, B. subtilis, A. niger, and Penicillium were 99.84%, 99.02%, 93.60%, 95.23%, respectively). Forthwith virucidal (SARS-CoV-2) efficiency of the A-A filter can reach 99.90% for 5 min. The filter shows good stability after 10 heating cycles, demonstrating its reusability.

6-Bromo-pyridine-2-carboxamide.

In the the title compound, C(6)H(5)BrN(2)O, an intra-molecular N-H⋯N hydrogen bond generates an S(5) ring. In the crystal structure, inter-molecular bifurcated N-H⋯(O,O) hydrogen bonds link the mol-ecules, leading to sheets propagating in (100).

Structural Properties and Dynamics of Thiophene in Sub/Supercritical Carbon Dioxide from Car-Parrinello Molecular Dynamics Simulations.

Structrual and dynamic properties of thiophene (C4H4S) in supercritical carbon dioxide were studied using Car-Parrinello molecular dynamics simulations. The geometries and energies optimized for the thiophene-CO2 complex show a stable C-H···O hydrogen bond interactions both in gas phase and in supercritical CO2. The radial distribution functions of CO2 around thiophene in the supercritical phase state show a correlation suggesting C-H···O hydrogen bond and S···C interaction. Local structural properties of the mixtures were investigated by angular-radial distributions and spatial distribution functions. The results show a mutually parallel arrangement between the thiophene plane and CO2 molecules at short distances and a high probability of the thiophene being located in the radial directions of the CO2 molecules. The decay of orientational correlations at 318.15 K shows slower relaxation compared to those of 298.15 K for first and second rank correlations. The vibrations of CO2 and thiophene molecules have been examined through an analysis of the velocity autocorrelation functions of the atoms. The C-H stretching modes of thiophene in the isolated configuration are less red-shifted and have a much narrower frequency range than that in the mixtures.

Computer simulation of the adsorption of thiophene in all-silica Y and Na-Y.

A grand canonical ensemble Monte Carlo simulation is performed to investigate the adsorption, heat of adsorption, and distributions of thiophene in all-silica Y and Na-Y zeolites. Biased particle insertions and deletions were implemented to allow the computation of equilibrium adsorption isotherms of such molecules. The calculated number of absorbed thiophene molecules in these zeolites is in good agreement with the experimental data. The calculated results show that the number absorbed of thiophene molecules in Na-Y is much greater than that in all-silica Y over the range of pressure. The calculated heat of adsorption is in good agreement with experimental results. The Na-Y zeolite, rather than all-silica Y, preferentially adsorbs the thiophene. A distribution analysis of the adsorbed phase structure reveals a different adsorption site in the zeolites.

Computer simulation of the adsorption of ethanethiol in silicalite of MFI and MOR.

The method of configurational-bias Monte Carlo simulation is used for investigating the adsorption and distributions of ethanethiol in MFI and MOR type zeolites. The calculated adsorption quantity of ethanethiol in MFI is close agreement with the experimental data by means of IR spectroscopy and thermogravimetry. The calculated results show the adsorption quantity of ethanethiol in MFI is much more than that in MOR under coequal conditions. The observation of distribution of MFI is attributed to preferential adsorption of the ethanethiol molecules in the straight and zig-zag channels. In the intersection of straight channels and zig-zag channels, it accommodates the ethanethiol molecules like a reservoir. The straight channels for MOR accommodate all ethanethiol molecules almost, however, in the other channels, the ethanethiol molecules cannot be found.