Features of phospho- and amidohydrolases functioning in edaphotopes polluted by ore mill effluents

Досліджено вплив аеротехногенного типу забруднення ґрунту на активність деяких гідролітичних ферментів циклів азоту та фосфору. Показано, що біохімічна мобілізація фосфорорганічних і азотвмісних сполук ґрунту, забрудненого важкими металами, пригнічується в різній мірі. За чутливістю до аеротехногенного типу забруднення досліджені ферменти можна розташувати наступним чином: уреаза > лужна фосфатаза > аргіназа > АТФ-аза > кисла фосфатаза > амідаза. Досліджено вплив аеротехногенного типу забруднення ґрунту на активність деяких гідролітичних ферментів циклів азоту та фосфору. Показано, що біохімічна мобілізація фосфорорганічних і азотвмісних сполук ґрунту, забрудненого важкими металами, пригнічується в різній мірі. За чутливістю до аеротехногенного типу забруднення досліджені ферменти можна розташувати наступним чином: уреаза > лужна фосфатаза > аргіназа > АТФ-аза > кисла фосфатаза > амідаза. Influence of aerotechnogenic contamination of soils on activity of some hydrolytic enzymes of nitrogen and phosphorus cycles is examined. Biochemical mobilization of organophosphorous and nitrogen-bearing compounds in soils polluted by heavy metals is depressed to a variable extent. In descending order of sensitivity to the pollution, the studied enzymes ranked as follows: urease > alkaline phosphatase > arginase > АТPase > acid phosphatase > amidase

Regional cooperation of the CMEA countries in the Patent Information field

This paper continues the previous publications in World Patent Information on cooperation among the CMEA member countries in the patent information field1,2. Since the first publication more than three years have passed. All the subsystems of the International Patent Information System (IPIS) of CMEA countries entered operational phase. Some structural changes of IPIS were made, in particular, the ASBA service was expanded into the Subsystem of Processing and Retrieving Patent Information. The present paper gives a more complete description of the IPIS as a whole and the first results of its implementation.

Mechanosensitive cation channels in human leukaemia cells: calcium permeation and blocking effect

Cell-attached and inside-out patch-clamp methods were employed to identify and characterize mechanosensitive (MS) ionic channels in the plasma membrane of human myeloid leukaemia K562 cells. A reversible activation of gadolinium-blockable mechanogated currents in response to negative pressure application was found in 58 % of stable patches (n = 317). I-V relationships measured with a sodium-containing pipette solution showed slight inward rectification. Data analysis revealed the presence of two different populations of channels that were distinguishable by their conductance properties (17.2 ± 0.3 pS and 24.5 ± 0.5 pS), but were indistinguishable with regard to their selective and pharmacological properties. Ion-substitution experiments indicated that MS channels in leukaemia cells were permeable to cations but not to anions and do not discriminate between Na+ and K+. The channels were fully impermeable to large organic cations such as Tris+ and N-methyl-d-glucamine ions (NMDG+). Ca2+ permeation and blockade of MS channels were examined using pipettes containing different concentrations of Ca2+. In the presence of 2 mm CaCl2, when other cations were impermeant, both outward and inward single-channel currents were observed; the I-V relationship showed a unitary conductance of 7.7 ± 1.0 pS. The relative permeability value, PCa/PK, was equal to 0.75, as estimated at physiological Ca2+ concentrations. Partial or full inhibition of inward Ca2+ currents through MS channels was observed at higher concentrations of external Ca2+ (10 or 20 mm). No MS channels were activated when using a pipette containing 90 mm CaCl2. Monovalent mechanogated currents were not significantly affected by extracellular Ca2+ at concentrations within the physiological range (0-2 mm), and at some higher Ca2+ concentrations

A spin-selective approach for surface states at Co nanoislands

During recent years the surface electronic states of cobalt nanoislands grown on Cu(111) and Au(111) have been extensively studied and still yield fascinating results. Among magnetic surfaces, cobalt islands are particularly appealing because of their spin-polarized electronic states near the Fermi energy, involving localized d states of minority character, as well as free-like s–p states of majority character. We show here that these states are a sensitive probe to minute changes of structural details such as strain and stacking, and therefore constitute an ideal playground to study the interplay between structural and spin-related properties. Due to their size, cobalt islands on Cu(111) offer the additional opportunity to host single-magnetic adsorbates suitable for spin-polarized scanning tunneling microscopy and spectroscopy (SP-STM and SP-STS). We establish here that, in an energy interval just below the Fermi level, the spin-polarization of a transition-metal atom is governed by surface-induced states opposite in sign compared to the island, while the spin-polarization of Co-Phthalocyanine molecules is governed by molecular states. This opens up interesting perspectives for controlling and engineering spin-polarized phenomena at the nanoscale

Visualization of Compression and Spillover in a Coadsorbed System: Syngas on Cobalt Nanoparticles

Competitive adsorption and lateral pressure between surface-bound intermediates are important effects that dictate chemical reactivity. Lateral, or two-dimensional, pressure is known to promote reactivity by lowering energetic barriers and increasing conversion to products. We examined the coadsorption of CO and H2, the two reactants in the industrially important Fischer-Tropsch synthesis, on Co nanoparticles to investigate the effect of two-dimensional pressure. Using scanning tunneling microscopy, we directly visualized the coadsorption of H and CO on Co, and we found that the two adsorbates remain in segregated phases. CO adsorbs on the Co nanoparticles via spillover from the Cu(111) support, and when deposited onto preadsorbed adlayers of H, CO exerts two-dimensional pressure on H, compressing it into a higher-density, energetically less-preferred structure. By depositing excess CO, we found that H on the Co surface is forced to spill over onto the Cu(111) support. Thus, spillover of H from Co onto Cu, where it would not normally reside due to the high activation barrier, is preferred over desorption. We corroborated the mechanism of this spillover-induced displacement by calculating the relevant energetics using density functional theory, which show that the displacement of H from Co is compensated for by the formation of strong CO-Co bonds. These results may have significant ramifications for Fischer-Tropsch synthesis kinetics on Co, as the segregation of CO and H, as well as the displacement of H by CO, limits the interface between the two molecules. © 2013 American Chemical Society