Time filter

Source Type

Cycon M.,University of Silesia | Wojcik M.,Institute of Industrial Organic Chemistry | Borymski S.,University of Silesia | Piotrowska-Seget Z.,University of Silesia
Applied Soil Ecology | Year: 2013

Napropamide is one of the most commonly used herbicide in agricultural practice and its continuously application poses a potential risk for non-target soil microorganisms. Therefore, the objective of this study was to assess the impact of napropamide, applied at the field rate (FR, 2.25mgkg-1 of soil) and 10 times the FR (10*FR, 22.5mgkg-1 of soil) on soil microorganisms. To ascertain this impact, substrate-induced respiration (SIR), dehydrogenase (DHA), acid and alkaline phosphatases (PHOS-H and PHOS-OH), urease (URE) activities and changes in concentrations of NO3 - and NH4+ ions were determined. In addition, numbers of total bacteria and bacteria involved in soil nitrogen transformation were enumerated. A phospholipid fatty acid (PLFA) method was used to assess changes in the structure of soil microbial communities. Results showed negative effect of napropamide applied at the FR for SIR, the number of total bacteria, DHA, both PHOS, and URE at the beginning of the experiment. In 10*FR treated soil, a decreased activity of SIR, DHA, PHOS-OH and PHOS-H was observed over the experimental period. Nitrifying and N2-fixing bacteria appeared to be the most sensitive to napropamide. The concentration of NO3 - decreased in both napropamide-treated soils, whereas the concentration of NH4 + on day 28 in soil with 10*FR was 5 times higher than in the control. Analysis of the PLFA profiles showed that napropamide decreased the biomass of total, bacterial and fungal PLFAs on day 1, while at the end of the experiment in the soil treated with FR dosage of napropamide biomass of total, Gram-negative bacteria and fungi was significantly higher than those observed in the control. A principal component analysis of the PLFAs showed that napropamide application significantly shifted the microbial community structure on days 1 and 14. The degradation kinetics data showed that napropamide degradation by soil autochthonous microorganisms was relatively slow. The results indicated that a broad spectrum of analyze gives a better insight into the true effects of napropamide on soil microorganisms than the single assays. © 2013 Elsevier B.V.

Buczkowski D.,Institute of Industrial Organic Chemistry
Central European Journal of Energetic Materials | Year: 2014

The addition of many organic substances decreases the thermal stability and increases the explosive properties of ammonium nitrate(V). In order to determine how very material of plant origin would increase the risk of decomposition and explosion of ammonium nitrate(V), tests using the DTA method and the detonation properties were performed. The materials tested were milled ammonium nitrate(V) mixed with wheat flour, hard coal, rape seeds or wood dust. It was found that all of the mixtures tested decompose at significantly lower temperatures than ammonium nitrate(V) and ANFO explosive. Some of them decompose close to the melting temperature of ammonium nitrate(V) and their decomposition is violent. All of the mixtures tested are cap sensitive and some of them have smaller critical diameters than ANFO. The detonation velocities of the mixtures are lower than the detonation velocity of ANFO, but significantly higher than that of ammonium nitrate(V).

Florczak B.,Institute of Industrial Organic Chemistry
Central European Journal of Energetic Materials | Year: 2014

This paper presents the test results of viscosity changes, versus time and temperature, for the HTPB rubber based pre-binders used in the manufacture of heterogeneous solid rocket propellants (HSRP). A Brookfield HADV-II+PRO viscometer with a small sample adapter (SSA) and SC4-18 spindle, including a TC-550SD water bath, was used for the tests. The components of the prebinders tested were: HTPB-K domestic liquid synthetic rubber, R45M rubber, dioctyl adipate as the plasticizer, diisocyanate curing agents (DDI, IPDI) and various additives: triethanolamine (TEA), iron compounds, lecithin, glycerine and a solution of oxalic acid in glycerine, and difunctional aziridine amide. As a result of these tests, it was found that the additives have an influence on the viscosity versus time dependence. Moreover, the influence of temperature on the viscosity changes with time were compared for HTPB-K domestic rubber and R45M rubber based pre-binders. The experimental equations describing these changes were also determined.

Kwiatkowska M.,University of Lodz | Huras B.,Institute of Industrial Organic Chemistry | Bukowska B.,University of Lodz
Pesticide Biochemistry and Physiology | Year: 2014

The toxicity of herbicides to animals and human is an issue of worldwide concern. The present study was undertaken to evaluate toxic potential of widely used pesticide - glyphosate, its metabolites: aminomethylphosphonic acid (AMPA); methylphosphonic acid and its impurities: N-(phosphonomethyl)iminodiacetic acid (PMIDA), N-methylglyphosate, hydroxymethylphosphonic acid and bis-(phosphonomethyl)amine. We evaluated the effect of those compounds on hemolysis, hemoglobin oxidation, reactive oxygen species (ROS) formation and changes in morphology of human erythrocytes. The erythrocytes were exposed to different concentrations of glyphosate and its metabolites and impurities (0.01-5. mM) for 1, 4 and 24 h. Glyphosate, its metabolites and impurities induced a little hemolysis and hemoglobin oxidation. All changes were very low, even after 24 h incubation. Most of the investigated compounds induced reactive oxygen species formation from 0.25. mM, except the N-methylglyphosate which caused an increase in ROS formation from 0.5. mM. Moreover, the investigated xenobiotics did not change the size and shape (except bis-(phosphonomethyl)amine) of the human erythrocytes. Changes in human erythrocytes were observed only when high concentrations of the compounds were applied. Some investigated metabolites and impurities caused a slight stronger damage to human erythrocytes than a glyphosate. The results clearly show that the changes induced in the erythrocytes can occur only as a result of poisoning with these compounds. © 2014 Elsevier Inc.

The Morita-Baylis-Hillman adducts bearing a nitroxyl moiety were synthesized from 4-acryloyloxy-2,2,6,6-tetramethylpiperidine- 1-oxyl and aliphatic, aryl and heterocyclic aldehydes. © 2012 Zakrzewski; licensee Beilstein-Institut.

Discover hidden collaborations