Abstract  Though field data indicate that biogeochemical properties are heterogeneous, biogeochemical models are often applied without regard to local variation. In this paper, we examine how the spatial scale used to represent heterogeneity in ecosystem modeling affects aggregated forest stand nitrogen (N) dynamics. We conduct this spatial analysis using measured local variation in forest carbon and nitrogen distributions. By coupling field and modeling approaches, we address spatial scaling in the context of natural ecosystem dynamics. We model spatially explicit N dynamics in Douglas-fir (Pseudotsuga menziesii) forests using reaction-diffusion equations, in which Michaelis-Menten functions represent nitrogen transfer between plant, microbial, and soil pools, and nitrogen transport is approximated using diffusion. A stability analysis of the reaction terms in the absence of diffusion shows the model is very resilient to perturbation; consequently limit-cycle or oscillatory dynamics are not observed. The model is sensitive to variation in the maximum rate of plant nitrogen uptake as well as the Michaelis-Menten half-saturation constant for plant N uptake. The spatial scale of modeled heterogeneity does not significantly affect aggregated N dynamics in the Douglas-fir system; spatial resolution mainly affects the variance of stand nitrogen values. Analysis of post-perturbation dynamics shows that stand productivity is significantly reduced under frequent perturbations, especially when microbial biomass pools are seriously degraded. (C) 2005 Elsevier B.V. All rights reserved.

Abstract  The N, P, and S cycles in pristine forests are assumed to differ from those of anthropogenically impacted areas, but there are only a few studies to support this. Our objective was therefore to assess the controls of N, P, and S release, immobilization, and transport in a remote tropical montane forest. The study forest is located on steep slopes of the northern Andes in Ecuador. We determined the concentrations of NO3- N, NH4- N, dissolved organic N ( DON), PO4-P, dissolved organic P (DOP), SO4-S, dissolved organic S ( DOS), and dissolved organic C (DOC) in rainfall, throughfall, stem flow, lateral flow ( in the organic layer), litter leachate, mineral soil solution, and stream water of three 8 - 13 ha catchments ( 1900 - 2200 m a. s. l.). The organic forms of N, P, and S contributed, on average, 55, 66, and 63% to the total N, P, and S concentrations in all ecosystem fluxes, respectively. The organic layer was the largest source of all N, P, and S species except for inorganic P and S. Most PO4 was released in the canopy by leaching and most SO4 in the mineral soil by weathering. The mineral soil was a sink for all studied compounds except for SO4. Consequently, concentrations of dissolved inorganic and organic N and P were as low in stream water (TDN: 0.34 - 0.39 mg N l(-1), P not detectable) as in rainfall ( TDN: 0.39 - 0.48 mg N l(-1), P not detectable), whereas total S concentrations were elevated ( stream water: 0.04 - 0.15, rainfall: 0.01 - 0.07 mg S l(-1)). Dissolved N, P, and S forms were positively correlated with pH at the scale of soil peda except inorganic S. Soil drying and rewetting promoted the release of dissolved inorganic N. High discharge levels following heavy rainstorms were associated with increased DOC, DON, NO3- N and partly also NH4- N concentrations in stream water. Nitrate-N concentrations in the stream water were positively correlated with stream discharge during the wetter period of the year. Our results demonstrate that the sources and sinks of N, P, and S were element-specific. More than half of the cycling N, P, and S was organic. Soil pH and moisture were important controls of N, P, and S solubility at the scale of individual soil peda whereas the flow regime influenced the export with stream water.

Abstract  Herbivores directly and indirectly affect ecosystem functioning in forests. Feces deposition is a direct effect that supplies ephemeral N pulses to soils. Herbivore-mediated changes in plant N allocation and uptake are indirect effects that can also influence soil N availability. These effects may interact if defoliation influences the ability of plants to recover fecal N, and this may affect subsequent generations of herbivores. We added N-15-enriched insect feces (frass) to a series of replicated red oak, Quercus rubra, mesocosms that had been damaged experimentally and then followed the frass N over the course of 2 years. In the first season, some frass N was mineralized in the soil and leached in organic form from the mesocosms within 1 week of deposition. Within 1 month, frass N had been acquired by the oaks and enriched the foliage; late-season herbivores assimilated the frass N within the same growing season. In the second season, herbivore damage from the previous year lowered total leaf N contents and N-15 recovered in the foliage. A subsequent cohort of early-season herbivores fed on this foliage consequently derived less of their N from the previous year's frass, and feral leaf rollers colonized fewer of these saplings. The 0- to 5-cm soil fraction was the largest N sink measured, and 42% of the frass N was recovered in the soil. The results demonstrate that: (1) some frass N can be recycled rapidly into foliage and assimilated by successive cohorts of herbivore within the same season; (2) damage can affect N allocation in the following year's foliage, influencing N availability to and host selection by herbivores; and (3) leaching losses occur soon after deposition but are buffered by soil pools, which are the largest sinks for frass N.

Abstract  Two contrasting forest ecosystems located in close proximity to each other were selected for evaluating the importance of tree species and afforestation in relation to the water balance and the quality of the water leaving the forest root zone. Measurements included soil water content and the collection of precipitation, canopy throughfall, stem flow and soil solution on a weekly basis during 15 months (1999-2000). Soil solutions were extracted using suction probes installed at all major horizons within the upper 120 cm of a Norway spruce (N. spruce) stand (Picea Abies [L.] Karst.) and a European beech stand (Fagus Sylvatica L.) located on the same soil type. Soil solutions were analyzed for the content of all major ions, including nitrate. A water balance model (CoupModel) was used to estimate percolation rates beneath the root zone. Percolation at the beech stand was 292 mm and only 41 rnm at the N. spruce stand mainly due to differences in the interception loss. The highest annual leaching of Mg, K, Na, Al, Cl, SO4-S was noted in the N. spruce stand while leaching of NO3-N was highest in the beech stand, corresponding to 39 kg ha(-1) year(-1). By contrast, the annual leaching of NO3-N in the N. spruce stand was only 0.5 kg ha(-1) year(-1). The larger amount of NO3-N was leaving the beech forest soil despite the fact that the N. spruce stand had the highest atmospheric N-deposition. Thus, differences in NO3-N leaching between the stands must be related to differences in uptake and accumulation of N in the vegetation and within the upper 120 cm of the soil. Differences in the water balance and NO3-N leaching between beech and N. spruce stands call for further attention to the selection of tree-species on a soil type basis when planning future afforestation projects, particularly when such projects aim to improve the quality of water infiltrating to the groundwater zone. (c) 2006 Elsevier B.V. All rights reserved.

Abstract  Constructed wetlands are an effective yet costly strategy for reducing nitrate loading from agricultural subsurface drainage in the Midwestern United States. Targeting wetland placement to sites that intercept high nitrate loads and where topography permits optimal wetland sizing can maximize wetland nitrate removal efficiency while maintaining productive agriculture. The goals of this work were first to determine targeted locations for constructed wetlands to remove nitrate by applying a geospatial approach within an Indiana study region, and second to estimate the nitrate removal efficiency of these proposed wetlands. Criteria were developed from previously published wetland siting criteria associated with the Iowa CR.EP program and adapted to Indiana-specific conditions. Final criteria included location on cropped land and not within open waterways, size of upland contributing area, presence of tile drainage, and wetland-like topography. Within the study region, 18 locations were found to meet the targeting criteria for strategic wetland placement, requiring land conversion of 0.08% of the study region and intercepting 2.7% of flow from tile-drained lands. Estimated wetland nitrate removal efficiency was on average 37%, including land conversion of wetland and surrounding buffers, resulting in the removal of approximately 1.0% of all nitrate currently exported from tile-drained land in the study area. Wetland placement was most influenced by criteria relating to contributing area, exclusion of streams where wetlands could be potentially located, and topography. Adjusting criteria could allow for a larger set of constructed wetlands and achieve greater overall nitrate reductions at the watershed scale, but this set would likely include less efficient wetlands.

Abstract  Nitrogen derived from fertilizer runoff in the Mississippi River Basin (MRB) is acknowledged as a primary cause of hypoxia in the Gulf of Mexico. To identify the location and magnitude of nitrate runoff hotspots, and thus determine where increased conservation efforts may best improve water quality, we modeled the relationship between nitrogen inputs and spring nitrate loading in watersheds of the MRB. Fertilizer runoff was found to account for 59% of loading, atmospheric nitrate deposition for 17%, animal waste for 13%, and municipal waste for 11%. A nonlinear relationship between nitrate flux and fertilizer N inputs leads the model to identify a small but intensively cropped portion of the MRB as responsible for most agricultural nitrate runoff. Watersheds of the MRB with the highest rates of fertilizer runoff had the lowest amount of land enrolled in federal conservation programs. Our analysis suggests that scaling conservation effort in proportion to fertilizer use intensity could reduce agricultural nitrogen inputs to the Gulf of Mexico, and that the cost of doing so would be well within historic levels of federal funding for agriculture.

Abstract  Wood ash was applied to a forest ecosystem with the aim to recycle nutrients taken from the forest and to mitigate the negative effects of intensive harvesting. After two years, the application of 8.000 kg ha(-1) of wood ash increased soil exchangeable Ca and Mg. Similarly, an increase in Ca and Mg in the Norway spruce fine roots was recorded, leading to significant linear correlations between soil and root Ca and soil and root Mg. In contrast to these macronutrients. the micronutrients Fe and Zn and the toxic element Al decreased in the soil exchangeable fraction with the addition of wood ash, but not in the fine roots. Only Mn decreased in soil and in fine roots leading to a significant linear correlation between soil and root Mn. In soil, as well as in fine roots, strong positive correlations were found between the elements Ca and Mg and between Fe and At. This indicates that the uptake of Mg resembles that of Ca and that of Al that of Fe. With the wood ash application. the pH increased from 3.2 to 4.8. the base saturation from 30% to 86%. the molar basic cations/Al ratio (BC/Al) of the soil solution from 1.5 to 5.5, and the molar Ca/Al ratio of the fine roots from 1.3 to 3.7. Overall, all below-ground indicators of soil acidification responded positively to the wood ash application within two years. Nitrate concentrations increased only slightly in the soil solution at a soil depth of 75-80 cm, and no signs of increased heavy metal concentrations in the soils or in the fine roots were apparent. This suggests that the recycling of wood ash could be an integral pan of sustainable forest management because it closes the nutrient cycle and reverses soil acidification.

Abstract  Cr-doped titanite (CaTiSiO5) pigments were synthesized through spray pyrolysis of aerosols generated from aqueous solutions containing colloidal silica, calcium chloride, titanium(IV) oxychloride and chromium(III) nitrate. This process yielded amorphous powders with spherical morphology and broad size distribution (<10 mu m) after thermal decomposition at 600 degrees C. The titanite phase was obtained by further calcination at 800 degrees C without any addition of flux agents. The brown color of the pigments can be attributed mainly to the existence of Cr(IV) ions occupying both, octahedral positions of Ti(IV) and tetrahedral position of Si(IV), together with a small amount of Cr(III) present as Cr2O3. The optimum pigment obtained by this method corresponded to a Cr/titanite mole ratio of 0.04. (C) 2008 Elsevier Ltd. All rights reserved.

Abstract  Powders of BaZr0.9Y0.1O3-delta (BZY10) were synthesised by spray pyrolysis from nitrate salt solutions for the first time. Differences in the powders produced were explored when the concentration of solution, atomisation frequency, aerosol flow rate and furnace temperature were varied. X-ray powder diffraction (XRD) was used to determine that powders produced using a furnace temperature of 800 degrees C were of single phase. Powder that was produced using a higher atomisation frequency and a lower salt solution concentration resulted in a favourable particle size distribution and morphology for sintering. A density of approximately 91 % of the theoretical density (TD) was achieved by sintering at 1500 degrees C for 1h in flowing air, significantly higher than is achieved with commercial BZY10 powders using these conditions. This constitutes a significant lowering of the sintering temperature of this oxide. (C) 2008 Elsevier Ltd. All fights reserved.

Abstract  Rate constants for the reactions of OH radicals with four C(6)-C(10) cycloalkenes have been measured at 297 ± 2 K using a relative rate technique. The rate constants (in units of 10(-11) cm(3) molecule(-1) s(-1)) were cyclohexene, 6.35 ± 0.12; cis-cyclooctene, 5.16 ± 0.15; cis-cyclodecene, 4.18 ± 0.06; and 1-methyl-1-cyclohexene, 9.81 ± 0.18, where the indicated errors are two least-squares standard deviations and do not include uncertainties in the rate constant for the reference compound 1,3,5-trimethylbenzene. In addition, a rate constant of (4.8 ± 1.3) × 10(-11) cm(3) molecule(-1) s(-1) was derived for the reaction of OH radicals with 1,6-hexanedial, relative to our measured rate constant for OH + cyclohexene. Analyses of products of the OH + cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene reactions by direct air sampling atmospheric pressure ionization mass spectrometry and/or by combined gas chromatography-mass spectrometry showed the presence of products attributed to cyclic 1,2-hydroxynitrates and the dicarbonyls 1,6-hexanedial, 6-oxo-heptanal, and 1,8-octanedial, respectively. These dicarbonyl products, which are those formed after decomposition of the intermediate cyclic 1,2-hydroxyalkoxy radicals, were quantified as their dioximes, with molar formation yields of 76 ± 10%, 82 ± 12%, and 84 ± 18% from the cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene reactions, respectively. Combined with literature data concerning 1,2-hydroxynitrate formation from OH + alkenes and the estimated fractions of the overall reactions proceeding by H-atom abstraction, 90 ± 12%, 95 ± 13% and 108 ± 20% of the products or reaction pathways from the OH radical-initiated reactions of cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene in the presence of NO are accounted for.

Abstract  Much of the NO3 in the riverine waters of the upper Mississippi River basin in the United States originates from agricultural land used for corn (Zea mays L) and soybean (Glycine max [L] Merr.) production. Cover crops grown between maturity and planting of these crops are one approach for reducing losses of NO3. In this experiment, we evaluated the effectiveness of oat (Avena sativa L.) and rye (Secale cereale L.) cover crops in reducing NO3 concentrations and loads in subsurface drainage water. The oat fall cover crop was broadcast seeded into living corn and soybean crops before harvest in late August or early September and was killed by cold temperatures in late November or early December The rye winter cover crop, which had already been used annually for four years, was planted with a grain drill after corn and soybean harvest, overwintered, grew again in the spring, and was killed with herbicides before main crop planting. These treatments were evaluated in subsurface-drained field plots with an automated system for measuring drainage flow and collecting proportional samples for analysis of NO3 concentrations from each plot. The rye winter cover crop significantly reduced drainage water NO3 concentrations by 48% over five years, but this was less than the 58% reduction observed in its first four years of use. The oat fall cover crop reduced NO3 concentrations by 26% or about half of the reduction of the rye cover crop. Neither cover crop significantly reduced cumulative drainage or nitrate loads because of variability in cumulative annual drainage among plots. Both oat and rye cover crops are viable management options for significantly reducing NO3 losses to surface waters from agricultural drainage systems used for corn and soybean production. Published by Elsevier B.V.

Abstract  Blasting by ammonium nitrate fuel oil (ANFO) is considered to convert rock deserts into rich soil areas because it can break up the rocks and diffuse nitrogenous nutritional ions (NH4+, NO3-) into the rock fragments. However, various nutritional ions, other than the nitrogenous ones, are required in terms of the fertilization of rock areas. The purpose of this study was to establish a blasting method by using ANFO with fertilizers, KNO3 and/or (NH4)(2)HPO4, for diffusing nutritional ions into rock fragments. In this study, the hazard evaluation of the ANFO with KNO3 and/or (NH4)(2)HPO4 was conducted with the help of sealed cell differential scanning calorimetry (SC-DSC). Further, the diffusion amount of the nutritional ions and the blasting effect of the ANFO with KNO3 and (NH4)(2)HPO4 were investigated with the help of field experiments. The results of the SC-DSC revealed nearly identical decomposition temperatures and decomposition heats for the ANFO alone and the ANFO with KNO3 and/or (NH4)(2) HPO4. Thus, it is considered that the ANFO with KNO3 and/or (NH4)(2)HPO4 could be treated as similar to the ANFO alone. The results of the field experiments also revealed the presence of NH4+, K+ and NO3 in the rock fragments blasted by the ANFO with KNO3 and (NH4)(2)HPO4. The content of the nutritional ions in the rock fragments blasted by the ANFO with KNO3 and (NH4)(2) HPO4 was more than that ions in the rock fragments blasted by the ANFO alone, and it was approximately equal to that found in natural soil. These results may indicate that blasting by the ANFO with KNO3 and (NH4)(2)HPO4 can control the amount of nitrogenous ions diffused into a rock area.

Abstract  Cosmic rays in the upper troposphere (30000 feet to 50000 feet; 9000 meters to 15000 meters) initiate the nuclear chemical reaction: (1)n + N-14 double right arrow C-14 + H-1. Previous research has shown a strong effect of latitude on the abundance of neutrons from cosmic rays. However, to date, there has been little exploration of the relationship between the latitude effect for cosmic-ray neutrons and latitudinal variations of stable isotope ratios in aerosols and foliage. In this study, aerosol samples (PM 4.5) and foliage samples were collected in Singapore in November 2009, February 2010 and July 2010 and in Fairbanks, Alaska, U.S.A. in January 2010, April 2010 and September 2010. Ion chromatography, gas chromatography-mass spectrometry, and element mass spectrometry were used to measure anion concentrations and nitrogen and oxygen stable isotope ratios in nitrogen oxide ions of the aerosol samples, as well as to measure carbon and nitrogen stable isotope ratios in the foliage samples. The average value of delta N-15/14 in foliage in Fairbanks was -1.84 [per mil], whereas the average value in Singapore was -1.3 [per mil]. These results show a clear latitude effect on delta N-15/14 in foliage. Furthermore, the average value of delta N-15/14 in the nitric-oxide substances in the aerosol samples in Fairbanks was -2.70 [per mil], whereas the average value in Singapore was +7.61 [per mil], demonstrating that delta N-15/14 in nitric-oxide substances from aerosol samples also experiences a latitude effect. However, no clear latitudinal pattern was observed for delta C-13/12 in foliage or for delta O-18/16 in nitric-oxide substances from aerosols. In both Singapore and Fairbanks, it was observed that values of delta N-15/14 in nitric-oxide substances from aerosols were correlated with declination. The value of delta N-15/14 in nitric-oxide substances from aerosols in Fairbanks increased with increasing declination due to more active conversions from N-14 to C-14 by neutron bombardment.

Abstract  Sampling of the water used for hand washing in aeroplane lavatories (in-flight water) was conducted on passenger flights between Narita International Airport in the suburbs of Tokyo, Japan and Changi International Airport in Singapore from August 22, 2009 to July 29, 2010. These samples were analyzed for anion concentrations using ion chromatography (IC) and for stable nitrogen isotope ratios in the nitrate ion (NO3-) using GC- mass spectrometry (GC-MS). The results of these analyses indicate that in-flight water exhibits variations in stable isotope ratios and anion concentrations during flights. A very low isotopic ratio of delta(delta) N-15/N-14 = -368.5 [per mil] was measured for the in-flight water on an aircraft flying over thunder clouds on November 15, 2009, at 10 degrees North offshore of Luzon Island in the Philippines. If the extremely low stable nitrogen Isotope ratio at -368.5 [per mil] measured on November 15, 2009, at 10 degrees North is excluded, a rough trend consisting of the highest stable nitrogen isotope ratios at nearly the same altitude was observed at neighboring positions of declination. The concentration of the NO3- ion was highly variable in the sampled in-flight water during flight. The following nuclear chemical reaction is well known. (1)(0)n + N-14(7)-> C + H-1(1) If this nuclear chemical reaction occurred, the nitrate ion (NO3-) was converted to carbonate ion (CO32-). Hence, the carbon in the product CO32- would be carbon-14, a radioisotope. The passengers and crew members on flights may use hi-flight water for hand washing, gargling with mouth wash and as drinking water. Internal exposure to radiation in the form of carbon-14 for these individuals is more likely.

Abstract  Mesoporous Ba/MCM-41 type materials (Ba/MCM-41) with high Ba/Si molar ratios between 0.025 and 0.1 were synthesized by direct hydrothermal synthesis. The samples were characterized by XRD, nitrogen adsorption, TGA-DTA, FTIR, SEM-EDS, and TEM techniques. BET surface areas of samples with various Ba loadings were found between 722 and 931 m(2)/g with 28 A average pore size, which is consistent with the pore size of 30 A for pure MCM-41 samples synthesized by the same procedure. The crystal structures of synthesized MCM-41 and Ba/MCM-41 were confirmed by XRD analysis. Among the investigated Ba/MCM-41 samples, the formation of barium oxide and barium nitrate species besides silicates was also observed in the high angle region XRD patterns.

Abstract  THE TITLE COMPOUND (SYSTEMATIC NAME: 1,1',2,2'-tetra-phenyl-2,2'-azinodiethanone), C(28)H(20)N(2)O(2), was obtained by the reaction of benzil monohydrazone with chromium(III) nitrate. The dibenzyl-idene hydrazine unit is nearly planar (r.m.s. deviation = 0.073 Å) and the two benzoyl units are oriented almost perpendicular to it [dihedral angle = 87.81 (2), 87.81 (2)°]. The mol-ecules are linked into chains along the c axis by C-H⋯O hydrogen bonds and the chains are cross-linked via C-H⋯π inter-actions involving the benzoyl phenyl rings.

Abstract  The title compound, [Cd(C(5)H(3)N(2)O(2))(N(3))](n), has been pre-pared by the reaction of pyrazine-2-carboxylic acid, cadmium(II) nitrate and sodium azide. In the structure, the Cd(II) atom is six-coordinated by two azide anions and three pyrazine-2-carboxyl-ate ligands. Each pyrazine-2-carboxyl-ate ligand bridges three Cd(II) atoms, whereas the azide ligand bridges two Cd(II) atoms, resulting in the formation of a two-dimensional metal-organic polymer developing parallel to the (100) plane.

Abstract  Oxidative stress contributes to the cascade, leading to dopamine cell degeneration in Parkinson's disease. However, oxidative stress is intimately linked to other components of the degenerative process, such as mitochondrial dysfunction, excitotoxicity, nitric oxide toxicity and inflammation. It is therefore difficult to determine whether oxidative stress leads to or is a consequence of, these events. Oxidative stress was assessed by estimating lipid peroxidation product in the form of thiobarbituric acid reactive substances, nitric oxide in the form of nitrite & nitrate. Enzymatic antioxidants in the form of superoxide dismutase, glutathione peroxidase, catalase, ceruloplasmin and non enzymatic antioxidant vitamins e.g. vitamin E and C in either serum or plasma or erythrocyte in 40 patients of Parkinson's disease in the age group 40-80 years. Trace elements e.g. copper, zinc and selenium were also estimated. Plasma thiobarbituric acid reactive substances and nitric oxide levels were Significantly high but superoxide dismutase, glutathione peroxidase, catalase, ceruloplasmin, vitamin-E, vitamin-C, copper, zinc and selenium levels were significantly low in Parkinson's disease when compared with control subjects. Present study showed that elevated oxidative stress may be playing a role in dopaminergic neuronal loss in substentia nigra pars compacta and involved in pathogenesis of the Parkinson's disease.

Abstract  Reducing nitrogen (N) leaching to groundwater requires an improved understanding of the effect of microtopography on N fate. Because of the heterogeneity between positions, ridge tilled fields, frequently used in intensive agriculture, should be treated as two distinct management units. In this study, we measured N dynamics in plastic- mulched ridges and bare furrows with the goal of developing more sustainable agricultural practices with optimal gains, namely crop production versus limited impacts on water quality. We investigated: (1) biomass production; (2) crop N uptake; (3) N retention in soil; and (4) N leaching using N-15 fertilizer in a radish crop. Broadcast mineral N fertilizer application prior to planting resulted in high total leaching losses (of up to 390 N kg ha(-1)). The application of plastic mulch in combination with local fertilizer management did not help to reduce N leaching. At all fertilizer N rates, the mean NO3 (-) concentrations in seepage water were found to be above the WHO drinking water standard of 50 mg NO3 (-) l(-1). To reduce NO3 (-) leaching, we recommend: (1) decreasing the fertilizer N rates to a maximum of 150 kg N ha(-1); (2) applying fertilizer N in 3-4 split applications according to the plant's N needs; (3) applying fertilizer N to the ridges (after their formation) to avoid losses from the furrows; and (4) increasing the soil organic matter content to enhance the water and nutrient retention by covering the furrows with plant residues.

Abstract  The production of biogas from renewable resources is a common technology for combined heat and power provision. Small scale plants represent de- centralized energy supply for communities and are an important part of regional development and de-central usage of renewable resources. To avoid conflicts with the food- and feedstock provision the usage of main crops as main source for biogas production should be avoided. Intercrops are planted on agricultural fields between the periods for main crops and may be used to provide biogas feedstock fields besides main crops. This biogas can be used in decentralized biogas units to produce electricity and heat. Beside the energetic usage of intercrops possible positive side effects are analysed. The usage of intercrops instead of mulching has a potential to decrease emissions of nitrates to water and nitrous oxide to air. Especially emission reduction of nitrous dioxide, a potent greenhouse gas, is part of the analysis. For the calculation of environmental effects of agriculture with intercrops the ecological evaluation method of the Sustainable Process Index (SPI) is used (Narodoslawsky et. al., 2008).

Abstract  A comparative assessment of the contents of total nitrogen, ammonium, nitrates, and fungal and bacterial biomasses and of the activity of nitrogen transformation in fresh casts of Aporrectodea caliginosa and in a soddy-podzolic soil was performed. The total content of nitrogen in the casts was similar to or slightly higher than that in the soil; the content of inorganic forms of nitrogen in the casts was significantly higher than in the soil. The intensities of ammonification, nitrification, and denitrification and the pool of microbial biomass with a predominance of fungi during the 1.5-week-long incubation were also significantly higher in the casts. The activity of nitrogen fixation in the casts was lower than that in the soil. In the course of the incubation, the values of these parameters in the casts became closer to those in the soil. The inhibition of fungi in the casts with cycloheximide resulted in an increasing content of inorganic nitrogen and a higher activity of denitrification. In our opinion, this phenomenon is related to the fact that limitation of the fungal growth decreases the intensity of immobilization of nitrates and the fungal competition with denitrifying bacteria for available carbon. It was supposed that the activation of the fungal growth via application of plant substrates into the soil with a high population density of earthworms could suppress the emission of gaseous nitrogen compounds. The soil processing by earthworms had a positive effect on the soil properties.

Abstract  The electrochemical behavior of steel alloy in ethylene glycol-water mixture was investigated by electrochemical methods. The results obtained showed that corrosion rate was decreased with increasing ethylene glycol concentration. The effect of nitrite and nitrate as inhibitor was studied and higher inhibition efficiency was obtained for nitrite. It was found that surface passivation occurred in presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl- ions and the adsorption isotherm basically obeys the Flory-Huggins adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and reveal that the adsorption process is spontaneous.

Abstract  BACKGROUND AND PURPOSE: Nitrate tolerance, the loss of vascular responsiveness with continued use of nitrates, remains incompletely understood and is a limitation of these therapeutic agents. Vascular superoxide, generated by uncoupled endothelial NOS (eNOS), may play a role. As arginase competes with eNOS for L-arginine and may exacerbate the production of reactive oxygen species (ROS), we hypothesized that arginase inhibition might reduce nitrate tolerance.

EXPERIMENTAL APPROACH: Vasodilator responses were measured in aorta from C57Bl/6 and arginase II knockout (argII -/-) mice using myography. Uncoupling of eNOS, determined as eNOS monomer : dimer ratio, was assessed using low-temperature SDS-PAGE and ROS levels were measured using L-012 and lucigenin-enhanced chemiluminescence.

KEY RESULTS: Repeated application of glyceryl trinitrate (GTN) on aorta isolated from C57Bl/6 mice produced a 32-fold rightward shift of the concentration-response curve. However this rightward shift (or resultant tolerance) was not observed in the presence of the arginase inhibitor (s)-(2-boronethyl)-L-cysteine HCl (BEC; 100 µM) nor in aorta isolated from argII -/- mice. Similar findings were obtained after inducing nitrate tolerance in vivo. Repeated administration of GTN in human umbilical vein endothelial cells induced uncoupling of eNOS from its dimeric state and increased ROS levels, which were reduced with arginase inhibition and exogenous L-arginine. Aortae from GTN tolerant C57Bl/6 mice exhibited increased arginase activity and ROS production, whereas vessels from argII -/- mice did not.

CONCLUSION AND IMPLICATIONS: Arginase II removal prevents nitrate tolerance. This may be due to decreased uncoupling of eNOS and consequent ROS production.

Abstract  NiO-Al2O3 samples of varying composition were prepared from their nitrate solutions using NH4OH. The catalysts were obtained by the thermal treatment, in air, at 450, 550, 650 and 750-degrees-C. X-ray investigation of the thermal products was made. The textural properties of these thermal products were determined from the nitrogen adsorption measurements at 77 K. The surface acidities at 473 and 673 K were measured by the chemisorption of pyridine. The catalytic conversion of isopropanol as well as the catalytic cracking of cumene were measured on NiO-Al2O3 samples at 473 and 673 K respectively. The surface area slightly increased upon rising the calcination temperature from 450-degrees to 550-degrees-C and then continuously decreased upon further rise of the calcination temperature. The mean pore radius showed continuous increase with the increase of the calcination temperature. The surface acidity measured at 473 K decreased with the increase in NiO content. The reverse was found for acidities measured at 673 K. Catalytic dehydration of isopropanol is related to the surface acid density while the dehydrogenation of this alcohol depends on NiO content. The cracking of cumene is related to the N(acid)/g, measured at 673 K.