Plasma-etching is a powerful tool in the determination of the resistance of the sublayer of skinned asymmetric hollow fiber membranes of poly (2,6-dimethyl-1,4-phenylene oxide). Using a resistance model and data provided by etched hollow PPO fiber membranes it is possible to predict the ultimate selectivity of the total membrane for helium over nitrogen and oxygen over nitrogen. From this model...

In order to recycle nitrogen from nitrogen-rich waste streams, particularly protein waste, we studied the decarboxylation of pyroglutamic acid and glutamic acid in a one-pot reaction to bio-based 2-pyrrolidone. After the screening of a wide range of supported Pd and Pt catalysts, 5 wt% Pd/Al2O3 displayed the highest yield (70%) and selectivity (81%) for the decarboxylation of pyroglutamic acid ...

In this study, Mn (III) salen complex was synthesized and immobilized onto the graphene oxide, which is modified by 3-chloropropyltrimethoxy silane. Heterogeneous catalyst was characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectra, nitrogen adsorption−desorption isotherm and atomic absorption spectroscopy. The catalyt...

Nitrogen mustards alkylate DNA primarily at the N7 position of guanine. Using an approach analogous to that of the Maxam-Gilbert procedure for DNA sequence analysis, we have examined the relative frequencies of alkylation for a number of nitrogen mustards at different guanine-N7 sites on a DNA fragment of known sequence. Most nitrogen mustards were found to have similar patterns of alkylation, ...

In this study, several dearomative reactions of N-aromatic zwitterions were carried out to determine the factors controlling site selectivity. A series organometallic species applied as nucleophiles for additions, which revealed that chelation between metal and nitrogen anion dominantly affected selectivity reaction in zwitterions. cascade process, involving addition followed by intermolecular ...

A series of porous organic cages is examined for the selective adsorption of sulfur hexafluoride (SF6) over nitrogen. Despite lacking any metal sites, a porous cage, CC3, shows the highest SF6/N2 selectivity reported for any material at ambient temperature and pressure, which translates to real separations in a gas breakthrough column. The SF6 uptake of these materials is considerably higher th...

Analysis of the rumen content was carried out on a total of 43 samples taken from deer (Capreolus capreolus L.) shot on the hunting grounds of "Barajevska Reka" (Serbia). All animals were males and were hunted in the early morning. The experiment was set as a randomized trial with four treatments (spring, summer, autumn and winter) and an uneven distribution of animals per treatment. Organolept...

On the way towards a sustainable low-carbon future, the design and construction of chemical or physical adsorbents for CO(2) capture and clean energy storage are vital technology. The incorporation of accessible nitrogen-donor sites into the pore walls of porous adsorbents can dramatically affect the CO(2) uptake capacity and selectivity on account of the dipole-quadrupole interactions between ...

In this work, the photocatalytic reduction of nitrate in water was examined using zinc oxide loaded with platinum nanoparticles and formic acid as a hole scavenger (electron donor). The data obtained in the structural characterization and in the nitrate photoreduction experiments showed that 1wt% Pt/ZnO photocatalyst had the highest photocatalytic activity and selectivity toward nitrogen. Selec...

Aquaporins are channel proteins present in the plasma and intracellular membranes of plant cells, where they facilitate the transport of water and/or small neutral solutes (urea, boric acid, silicic acid) or gases (ammonia, carbon dioxide). Recent progress was made in understanding the molecular bases of aquaporin transport selectivity and gating. The present review examines how a wide range of...