Inf3 Sup Research Articles

Detection of sulphur dioxide in the air using Scotch pine needles

Air quality is especially important in surface layers, for it is this layer that provides the living components of environment with the needed oxygen and carbon dioxide. Various air polluting gases penetrate cells affecting and contaminating them. Chloroplast shell of some pine species, for instance, doubles under the impact of carbon dioxide which is followed by tillacoids swelling and reduction.Literature provides opinions of some authors, who consider Scotch pine needle to be a biological indicator of sulphur dioxide. Others object to it basing on the observations of physiological development.The property of a Scotch pine as that of biological indicator manifests in SO2 absorption by its needles. The analysis of total content of SO2 in the needles shows an increase of SO2 concentration.Sulphur in the needles is found in the form of organically bound sulphur, aminoacids, hormones as well as in the form of sulphates.Basing on our previous analysis we have generalized the data on the correlation concentrations of sulphur dioxide in the air and general concentrations of sulphur in the needles. We have supplemented the observations with the analyses of organically bound sulphur and concentrations of nonorganic sulphur. According to research data, needles contain a characteristic and rather stable quantity of organically bound sulphur.So we may state that the SO inf4 (sup2-) concentration and the amount of SO2 absorbed from the air are interdependent.Some authors state that SO inf4 (sup2-) content in the soil doesn't affect sulphur content in pine needles. That is why we studied the affect of SO inf4 (sup2-) content in the soil on sulphur content in Scotch pine needles.We could prove this statement by means of various kinds of analyses only partially. The ion transport is affected by the presence of other ions, pH and a lot of other factors.What may be said for sure is that different qualities of soils gave only minor and insignificant deviations.Hence our assumption about the SO2 contamination from air, proved by its effect on the soils, turns to suit approximate measurements.

Mercury antagonists: Effects of sodium chloride and sulfur group (VIa) compounds on excystment of the brine shrimp artemia

Brine shrimp excystment, although highly resistant, is severely inhibited by mmolar mercuric chloride. The presence of 100 mmolar NaCl largely prevents the toxic response. The chloride effect can be explained if the toxic Hg species, neutral HgCl2, is converted into HgCl inf3 sup2− and HgCl inf4 sup2− since charged species not likely to penetrate cyst walls.

Effects of nitrogen dioxide on selected soil processes

Nitrogen dioxide gas was rapidly absorbed by soil. After a 15 min incubation at 25°C, soil at a moisture content of 16% absorbed 99% of the NO2 introduced into the gas-phase volume of a closed system. The presence of microorganisms hatl no influence on the rate of absorption of the gas by soil. The absorption of NO2 by sandy clay loam soil was not an oxygen- or temperature-dependent process nor did it depend upon the moisture content of the soil. These physical factors acquired significance only in determining the initial rate of absorption of the gas and the rate at which NO2 diffused through the soil. Exposure of soil to NO2 resulted in substantial increases in the levels of NO inf2 sup− N in the soil. Chemical oxidation of the NO inf2 sup− N resulted in an increase in NO inf3 sup− N levels. During a 14-day incubation, NO inf2 sup− N concentrations in sterile soil exposed to an atmosphere containing 100 μg ml−1 of NO2 decreased from 190 μg g−1 of soil to 105 μg g−1 with an accompanying increase in NO inf3 sup− N from 2 μg g−1 to 63 μg g−1 of soil. Nitrogen dioxide severely inhibited the growth of both aerobic and anaerobic asymbiotic N2-fixing bacteria in soil. After a 48 h incubation at 25°C, soil aggregates exposed to an atmosphere containing 100 μg ml−1 of NO2 contained 88% and 98% fewer aerobic and anaerobic N2-fixing bacteria, respectively. C2H2-reduction measurements showed that nitrogenase synthesis and activity in artificial soil aggregates amended with 2% glucose were inhibited by 20% and 48%, respectively, when exposed to atmospheric concentrations of 35 and 3.5 μg ml−1 of NO2, respectively.

Stability and crystal field splitting of N inf2 sup− in Barium Azide

The crystal field splitting of the ground2πg state and the equilibrium orientation of the Ninf2sup− radical in the monoclinic barium azide are calculated employing a point ion representation of the lattice potential and assuming three different plausible trapping sites for the radical. When the Ninf2− is assumed to replace an azide ion which is parallel to thec axis of the unit cell, the previously suggested trapping site, the calculated crystal field splitting is in order of magnitude agreement with the value deduced from theg shift in the ESR spectrum. The calculated orientational angle of the molecular axis with thec axis of the unit cell is 9.0 degrees which compares favorably with the experimentally determined angle of 5.0 ± 1.5 degrees. Possible reasons why the Ninf2− can not be trapped at the site of an azide ion which is perpendicular to the c axis are suggested from the calculation.

Marron-weare variational computation of energy differences for motions of C2H6, B2H6, CH3CH inf2 sup+ , and CH3BH2

The passage of D3dC2H6 and B2H6 toward a D2 h bridged structure, and the motion of a methyl proton maintaining C symmetry in C2H inf5 sup+ and CH3BH2 are described by integral Hellmann-Feynman computations in a Frost floating spherical Gaussian basis. Marron and Weare's variational corrections to the integral Hellmann-Feynman formula forAE between statesA andB are evaluated with variational functions of the form η(ψA/SAB-ψB)) used to refine the stateB. An analogous function ξ(ψB/SAB-ψA) refines state A. Both η and ξ are chosen variationally to minimize Marron and Weare's functional. No obvious advantage of the variational method became apparent in this simple application.