Export fluxes of dissolved, colloidal and particulate organic carbon, major and trace elements from the Ob River and its tributaries across seasons.

Riverine export fluxes of organic carbon (OC), major and trace elements remain at the forefront of environmental research in Arctic and subarctic regions, due mostly to high sensitivity of river hydrochemical parameters to climate warming and, at the same time, global importance of OC, nutrients and toxicants delivered by rivers to the Arctic Ocean. In contrast to reliable information on export fluxes of carbon and metals from the mainland to the Arctic Ocean by large and mid-size Arctic rivers, the majority of these studies quantify either dissolved (< 0.45 µm) or particulate suspended matter (PSM) fluxes, without mechanistic analyses of element speciation in most labile, low molecular weight (LMW) or colloidal form.

[Efficacy and safety of undenatured type II collagen in patients with knee osteoarthritis: a multicenter, prospective, double-blind, placebo-controlled, randomized trial].

Background: Non-pharmacological treatments based on collagen as a dietary supplement are emerging as a new area of interest to support preventive or therapeutic effects in patients with osteoarthritis (OA).

Aim: In a multicenter, prospective, double-blind, placebo-controlled, randomized study, to evaluate the effectiveness and safety of the use of the Artneo complex containing undenatured chicken collagen type II in patients with OA of the knee joints.

Materials And Methods: The study enrolled 212 outpatients from 12 centers in the Russian Federation with knee OA, stages II and III according to the Kellgren-Lawrence classification.

Fluvial carbon dioxide emissions peak at the permafrost thawing front in the Western Siberia Lowland.

In order to foresee the impact of permafrost thaw on CO emissions by high-latitude rivers, in-situ measurements across a permafrost and climate/vegetation gradient, coupled with assessment of possible physico-chemical and landscape controlling factors are necessary. Here we chose 34 catchments of variable stream order (1 to 9) and watershed size (1 to >10 km) located across a permafrost and biome gradient in the Western Siberian Lowland (WSL), from the permafrost-free southern taiga to the continuous permafrost zone of tundra. Across the south-north transect, maximal CO emissions (2.

Contrasted redox-dependent structural control on Fe isotope fractionation during its adsorption onto and assimilation by heterotrophic soil bacteria.

Despite the importance of structural control on metal stable isotope fractionation in inorganic and abiotic systems, the link between metal structural changes and related isotopic fractionation during reactions with organic surfaces and live cells remains poorly established. We conducted reversible adsorption of Fe(II) and Fe(III) on the surface of exopolysaccharide (EPS)-rich and EPS-poor , and we allowed Fe intracellular uptake by growing cells. We analyzed the Fe isotopic composition of the remaining fluid and cell biomass, and compared the isotopic fractionation during adsorption and assimilation reaction with relative changes in Fe structural status between aqueous solution and bacterial cells, based on available and newly collected X-ray absorption spectroscopy (XAS) observations.