Hexakis(tetra­aqua­sodium) deca­vanadate(V) dihydrate

The title compound, {[Na(H2O)4]6[V10O28]·2H2O}n, crystallized from a H2O/THF/CH3CN solution (pH ca 6) containing equimolar amounts of NaVO3 and N-(2-hydroxy­benz­yl)-N-(2-picol­yl)glycine. In the crystal structure, the deca­vanadate [V10O28]6− anion ( symmetry) is coordinated, via four terminal oxide ligands of V centres, to two dinuclear [{Na(H2O)3}2(μ-H2O)2]2+ units. Inter­connection of these aquasodium-ion-sandwiched deca­vanadates to chains parallel to [001] is effected by μ-[{Na(H2O)3}2(μ-H2O)2]2+ units, bridging adjacent deca­vanadates via O=V. The structure is consolidated by an extensive network of O—H⋯O hydrogen bonds

Intranight polarization variability in radio-loud and radio-quiet AGN

(Abriged) Intranight polarization variability in AGN has not been studied extensively so far. Studying the variability in polarization makes it possibly to distinguish between different emission mechanisms. Thus it can help answering the question if intranight variability in radio-loud and radio-quiet AGN is of the same or of fundamentally different origin. In this paper we investigate intranight polarization variability in AGN. Our sample consists of 28 AGN at low to moderate redshifts (0.048 < z < 1.036), 12 of which are radio-quiet quasars (RQQs) and 16 are radio-loud blazars. The subsample of blazars consists of eight flat-spectrum radio-quasars (FSRQs) and eight BL Lac objects. We find clear differences between the two samples. A majority of the radio-loud AGN show moderate to high degrees of polarization, more than half of them also show variability in polarization. There seems to be a dividing line for polarization intranight variability at P~5 per cent over which all objects vary in polarization. Only two out of 12 radio-quiet quasars show polarized emission, both at levels of P<1 per cent. The lack of polarization intranight variability in radio-quiet AGN points towards accretion instabilities being the cause for intranight flux variability whereas the high duty cycle of polarization variability in radio-loud objects is more likely caused by instabilities in the jet or changes of physical conditions in the jet plasma.Comment: Accepted for Publication in MNRAS (17 pages, 14 figures, 4 tables

Outer membrane protein folding from an energy landscape perspective

The cell envelope is essential for the survival of Gram-negative bacteria. This specialised membrane is densely packed with outer membrane proteins (OMPs), which perform a variety of functions. How OMPs fold into this crowded environment remains an open question. Here, we review current knowledge about OFMP folding mechanisms in vitro and discuss how the need to fold to a stable native state has shaped their folding energy landscapes. We also highlight the role of chaperones and the β-barrel assembly machinery (BAM) in assisting OMP folding in vivo and discuss proposed mechanisms by which this fascinating machinery may catalyse OMP folding

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

The enormous quantity of food wastes discarded annually force to look for alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the imperatives of the nowadays society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for recovery of added value compounds and detection by modern technologies and are an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels