Abstract  Diffusion, rheology, and small angle neutron scattering (SANS) data for organic phase 30 v/v %tributyl phosphate (TBP) samples containing varying amounts of water, nitric acid, and uranium or zirconium nitrate were interpreted from a colloidal perspective to give information on the types of structures formed by TBP under different conditions. Taken as a whole, the results of the different analyses were contradictory, suggesting that these samples should be treated as molecular solutions rather than colloids. This conclusion is supported by molecular dynamics (MD) simulations showing the existence of small, molecular aggregates in TBP samples containing water and nitric acid. Interpretation of TBP and nitric acid diffusion measurements from a molecular perspective suggest that nitric acid and metal species formed are consistent with the stoichiometric solvates that have traditionally been considered to exist in solution. (C) 2017 Elsevier B.V. All rights reserved.

Abstract  Reactive oxygen and nitrogen species (RONS such as H2O2, nitric oxide) confer redox regulation of essential cellular functions (e.g. differentiation, proliferation, migration, apoptosis), initiate and catalyze adaptive stress responses. In contrast, excessive formation of RONS caused by impaired break-down by cellular antioxidant systems and/or insufficient repair of the resulting oxidative damage of biomolecules may lead to appreciable impairment of cellular function and in the worst case to cell death, organ dysfunction and severe disease phenotypes of the entire organism. Therefore, the knowledge of the severity of oxidative stress and tissue specific localization is of great biological and clinical importance. However, at this level of investigation quantitative information may be enough. For the development of specific drugs, the cellular and subcellular localization of the sources of RONS or even the nature of the reactive species may be of great importance, and accordingly, more qualitative information is required. These two different philosophies currently compete with each other and their different needs (also reflected by different detection assays) often lead to controversial discussions within the redox research community. With the present review we want to shed some light on these different philosophies and needs (based on our personal views), but also to defend some of the traditional assays for the detection of RONS that work very well in our hands and to provide some guidelines how to use and interpret the results of these assays. We will also provide an overview on the "new assays" with a brief discussion on their strengths but also weaknesses and limitations.

Abstract  A simple, efficient, regioselective and diastereoselective method has been developed for the synthesis of diversely functionalized spirooxindole-pyrrolidines using 0.5 mol% of ceric ammonium nitrate in aqueous medium. All the new compounds are tested for in vitro antimicrobial activity. All the synthesized products have shown good antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus (Gram-positive organisms), Salmonella paratyphi, Pseudomonas aeruginosa and Salmonella typhi (Gram-negative organism).

Abstract  Glassy carbon electrodes were modified with composites containing cobalt tetraaminophenoxy phthalocyanine nanoparticles (CoTAPhPcNP), multi-walled carbon nanotubes (MWCNT) and gold nanorods (AuNRs). The modified electrodes were studied for their electrocatalytic behavior towards the reduction of hydrogen peroxide. Phthalocyanine nanoparticles significantly improved electron transfer kinetics as compared to phthalocyanines which are not in the nanoparticle form when alone or in the presence of multiwalled carbon nanotubes (MWCNTs). CoTAPhPcNP-MWCNT-GCE proved to be suitable for hydrogen peroxide detection with a catalytic rate constant of 3.45 x 10(3) M-1 s(-1) and a detection limit of 1.61 x 10(-7) M. Adsorption Gibbs free energy Delta G degrees was found to be -19.22 kJ mol(-1) for CoTAPhPcNP-MWCNT-GCE.

Abstract  The removal rate of NO3- -N is a key indicator for the performance evaluation of nitrogen removal in bioretention units. At present, most studies show that setting the submerged area and adding carbon (C) source can improve denitrification effect and removal rate of NO3- -N in bioretention units. However, experiments show that the dissimilatory nitrate reduction to ammonium (DNRA) has a significant impact on the N cycle and C/N ratio determines the reduction pathway of NO3- -N. Based on earlier findings, current work aimed to investigate the DNRA process in bioretention system by alternate wetting and drying operation mode, considering Total Nitrogen, NO3- -N and NH4+ -N as assessment indices. Results show that after a prolonged drought period, bioretention unit was able to remove NO3- -N mainly through DNRA with addition of C source. NH4+ -N accumulation occurs in dry period and the removal rate of NH4+ -N was lower than that of with C source. This phenomenon indicates that carbon is the main factor to determine the reduction pathway of NH4+ -N. Results of the microbial sequencing analysis revealed the presence of six common DNRA bacteria in bioretention: Pseudomonas (Pseudomonas), Bacillus (Bacillus), Thiobacillus (Thiobacillus), E. coli (Escherichia), phosphorus Vibrio (Desulfovibrio) and Desulfuvibibrio, which proves the existence of DNRA process in bioretention units.

Abstract  The anammox (anaerobic ammonium oxidation) process was considered a very efficient and economic wastewater treatment technology immediately after its discovery in 1995, thus research in this field was intensified. The anammox process is characterised by a high temperature optimum and is very sensitive to both temperature and pH fluctuations. The process can also be inhibited by many factors, including by its substrates, i.e. nitrite and ammonium (or its unionised forms: free ammonia and free nitrous acid). This paper presents a comprehensive study of the most important and recent findings on the influence of two parameters that are crucial in wastewater treatment, i.e. temperature and pH. Because both parameters may influence the anammox process simultaneously, a meta-analysis was conducted of the data from the literature. Although meta-analysis is commonly used in medical research, mathematical analysis of the literature data has become an interesting and important step in the environmental sciences. This paper presents information on the influence of both temperature and pH on process efficiency and microbial composition. Additionally, the responses of different operating systems on both temperature and pH changes are described. Moreover, the role of both adaptation to changed conditions and of pH control as well as indicated areas of process operation are discussed.

Abstract  As a result of climate changes, land use and agriculture have to adapt to new demands. Agriculture is responsible for a large part of the greenhouse gas (GHG) emissions that have to be urgently reduced in order to protect the environment. At the same time, agriculture has to cope with the challenges of sustainably feeding a growing world population. Reducing the use of the ammonia-nitrate fertilizers that are responsible for a large part of the GHGs released and that have a negative impact on carbon balance is one of the objectives of precision agriculture. One way to reduce N fertilizers without dramatically affecting grain yields is to improve the nitrogen recycling and remobilization performances of plants. Mechanisms involved in nitrogen recycling, such as autophagy, are essential for nutrient remobilization at the whole-plant level and for seed quality. Studies on leaf senescence and nutrient recycling provide new perspectives for improvement. The aim of this review is to give an overview of the mechanisms involved in nitrogen recycling and remobilization during leaf senescence and to present the different approaches undertaken to improve nitrogen remobilization efficiency using both model plants and crop species.

Abstract  Application of cattle manure and swine effluent to cropland builds nutrient pools, affects soil quality, and increases crop productivity. The objective of the present study was to evaluate the rate of change in soil nutrient concentration and soil chemical properties due to cattle manure and swine effluent application. The study was conducted from 1999 to 2008 near Tribune, KS, with 10 treatments (three levels each of cattle manure and swine effluent [P, N, and 2N], three levels of N fertilizer, and a control). Soil NO3-N, P, K, micronutrients, pH, and EC were measured annually. Swine P treatment resulted in significantly greater NO3 -N concentration in most years compared with all other treatments, followed by the Cattle 2N and Swine 2N treatments. The cattle treatments, in the order Cattle 2N > Cattle N > Cattle P, built the total N, soil P, and total C level significantly over the years compared with all other treatments. Soil pH did not change over time for most treatments except for the Swine P and Swine 2N treatments. Soil K, Cl, Fe, Zn, and Cu concentration increased significantly in cattle and swine treatments in 2008 compared with their initial level in 1999, and compared with check and inorganic fertilizer treatments. A significant build up in soil nutrients due to cattle and swine nutrient application suggests that they are good sources of many essential nutrients, in places where nutrients are limiting, but can cause excessive accumulation and increased environmental risk. A quick build up from Cattle 2N and Swine P applications calls for lower rates and periodic soil tests to determine need for further applications.

Abstract  Nitrogen oxides (NOx, including NO and NO2) play an important role in the formation of atmospheric particles. Thus, NOx emission reduction is critical for improving air quality, especially in severely air-polluted regions (e.g., North China). In this study, the source of NOx was investigated by the isotopic composition (δ(15)N) of particulate nitrate (p-NO3(-)) at Beihuangcheng Island (BH), a regional background site in North China. It was found that the δ(15)N-NO3(-) (n = 120) values varied between -1.7‰ and +24.0‰ and the δ(18)O-NO3(-) values ranged from 49.4‰ to 103.9‰. On the basis of the Bayesian mixing model, 27.78 ± 8.89%, 36.53 ± 6.66%, 22.01 ± 6.92%, and 13.68 ± 3.16% of annual NOx could be attributed to biomass burning, coal combustion, mobile sources, and biogenic soil emissions, respectively. Seasonally, the four sources were similar in spring and fall. Biogenic soil emissions were augmented in summer in association with the hot and rainy weather. Coal combustion increased significantly in winter with other sources showing an obvious decline. This study confirmed that isotope-modeling by δ(15)N-NO3(-) is a promising tool for partitioning NOx sources and provides guidance to policymakers with regard to options for NOx reduction in North China.

Abstract  Elucidating the relationship between characteristics of aerosol particles and optical absorption is important to deepen the understanding of atmospheric chemistry. Aerosol particles play significant roles in climate forcing via their optical absorption properties. However, the relationship between characteristics of aerosol particles and optical absorption remains poorly understood. Aerosol optical properties and morphologies were measured by a transmission electron microscope (TEM), cavity ring-down spectrometer (CRDS), a nephelometer and an Aethalometer in a urban site of Beijing from 24 May to 22 June. Five episodes were categorized according to the meteorological conditions and composition. The results showed that the clear episode (EP-2 and EP-4) featured as the low aerosol optical depth (AOD = 0.72) and fewer pollutants compared with haze (1.14) and fog (2.92) episodes and the particles are mostly externally mixed. The high angstrom ngstrom exponent (> 2.0) suggests that coarse particles were scarcely observed in EP-2 due to the washout of a previous heavy rain, whereas they were widespread in EP-4 (angstrom ngstrom exponent = 0.04), which had some mineral particles introduced from the north. In contrast, industry-induced haze (EP-1) and biomass-burning-induced haze (EP-5) were both affected by the south air mass. Compared with the EP-2 and EP-4, the AOD values and the size distribution of particles during EP-1 and EP-5 were much greater because of relatively high particle concentrations. All of the particles were classified into nine categories, i.e. S-rich, N-rich, mineral, K-rich, soot, tar ball, organic, metal and fly ash, on the basis of TEM analysis. In contrast to the EP-1, a large fraction of soot, which sticks to KCl, sulfate or nitrate particles, was detected during EP-5. Additionally, evident enhancement of light absorption was observed during the EP-5, which was mainly ascribed to both black carbon (BC) acceleration and other absorbing substances. However, soot was found mostly internally mixed with sulfate and nitrate during a soot fog episode (EP-3), resulting in evident enhancement of light absorption. The larger size distribution was likely to be caused by both hygroscopic growth and collision between particles during the aging. About 28% of particles were internally mixed during the foggy days, which favoured the light absorption. The comparison of all the episodes provides a deeper insight into how mixing states influence the aerosol extinction properties and also a clue as to how to control air pollution in the crop burning seasons.

Abstract  Partial-denitrification (nitrate (NO3--N) nitrite (NO2--N)) holds great potential in treating NO3--N contained wastewater, by combining with anammox process. In this study, performance of NO2--N production in partial-denitrification was investigated in two installations: sequencing batch reactor (SBR) and upflow sludge blanket (USB) reactor. Results indicated that partial-denitrification was established successfully in both of SBR and USB, with the NO2--N production rate (NPR) of 0.13-2.11 kg N m(-3) d(-1) and 0.90-13.03 kg N m(-3) d(-1), respectively. The NO3--N to NO2--N transformation ratio (NTR) was approximately 83.3% in SBR, while NTR of 51.0%-713% was obtained in USB. Sludge granulation was observed in both two reactors during the operation. In SBR, granular diameter of 1.5-2.0 mm was reached with sludge volume index (SVI) of 543 mL gSS(-1), and 2.0-3.0 mm in USB with SVI of 62.1 mL gSS(-1). Additionally, the ratio of COD to NO2--N (COD/NO2--N) and NO3--N to NOx--N percentage (NP) in partial-denitrification effluent demonstrated its suitability for subsequent anammox. While, partial-denitrification conducted in SBR was more suitable for low NO3--N wastewater (30 mg L-1), and USB was appropriate for high-strength sewage. Results obtained in this study provide a solid foundation for future applying partial-denitrification combined with anammox process in treating NO3--N contained wastewater. (C) 2017 Elsevier Ltd. All rights reserved.

Abstract  Nitrogen (N) availability is a major factor determining plant growth and productivity. Plants acquire inorganic N from the soil, mainly in the form of nitrate and ammonium. To date, researchers have focused on these N sources, and demonstrated that plants exhibit elaborate responses at both physiological and morphological levels. Mixtures of nitrate and ammonium are beneficial in terms of plant growth, as compared to nitrate or ammonium alone, and therefore synergistic responses to both N sources are predicted at different steps ranging from acquisition to assimilation. In this review, we summarize interactions between nitrate and ammonium with respect to uptake, allocation, assimilation, and signaling. Given that cultivated land often contains both nitrate and ammonium, a better understanding of the synergism between these N sources should help to identify targets with the potential to improve crop productivity.

Abstract  According to World Health Organization (WHO), fluoride has a narrow prescribed concentration level in drinking water (<1.5 mg L-1) and defluoridation of water is necessary to remove elevated concentrations of fluoride from water. In the present work, aluminium acetylacetonate was used as a precursor which was dissolved in methanol to produce Al2O3 nanoparticles by flame spray pyrolysis (FSP) technique. Al2O3 nanoparticles were characterized by various techniques (e.g. Brunauer-Emmet-Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier Transform Infrared (FTIR) to get an insight of their physicochemical properties. The effects of different variable parameters such as solution pH (3 11), contact time (5-180 min), initial fluoride concentration (0-30 mg L-1), temperature (25, 35 and 45 degrees C) and competing anions (chloride, nitrate, carbonate, sulfate and phosphate) were investigated to study the adsorption of fluoride from water. Among different kinetic and isotherm models studied, the pseudo-second-order model best described the kinetics, while equilibrium data were well fitted by the Langmuir isotherm model. The competing anions on defluoridation from water followed the order: phosphate > carbonate > sulfate > nitrate > chloride. Results from this study revealed the potential utility of Al2O3 nanoparticles for defluoridation of water. (C) 2017 Elsevier B.V. All rights reserved.

Abstract  This study considers the role of distance to the African source on the amount of deposition. To this end, dry and wet deposition was measured at a site close to Africa (Santa Cruz de Tenerife in the Canary Islands, SCO) and at a distant site located in NE Spain (La Castanya, Montseny, MSY). Because of the important influence of African influence on the buildup of particles in the atmosphere, we specifically addressed the contribution of North African events (NAF events) compared to other provenances (no-NAF events) in the wet and dry pathways at the two sites. At the site close to Africa, most of the crustal-derived elements were deposited in the dry mode, with NAF events contributing more than no-NAF events. Marine elements, by contrast, were mostly deposited at this site in the wet form with a predominance of no-NAF events. At MSY, wet deposition of SO4-S, NO3-N and NH4-N during NAF events was higher than at the site close to Africa, either in the wet or dry mode. This fact suggests that mineral dust interacts with pollutants, the mineral surface being coated with ammonium, sulphate and nitrate ions as the dust plume encounters polluted air masses in its way from North Africa to the Western Mediterranean. African dust may provide a mechanism of pollution scavenging and our results indicate that this removal is more effective in the wet mode at sites far away from the mineral source.

Abstract  Natural and anthropogenic chloride aerosols make up a significant fraction of atmospheric particulate matter and play important roles in the boundary layer chemistry. Here we provide a review of the mixing characteristics of chloride aerosols and the subsequent atmospheric implications, which are rarely considered in current field and modeling studies. Single-particle analytical techniques have shown that a large fraction of chlorides mix internally with other components, in particular inorganic salts and organic matters, instead of existing separately. In marine and coastal regions, high proportions of chloride aerosols usually mix with inorganic substances (e.g., Mg, Ca, K, N, S), while small quantities of them are coated by organic matter. In forest, grassland, and agricultural areas, most chlorides in biomass burning particles mix with or are coated by organics. In industrialized urban areas, the chloride aerosols often co-exist with heavy/transition metals (e.g., Zn, Pb) and are coated by organic materials in aged plumes. Moreover, secondary chlorides also mix with mineral dusts, nitrates, and sulfates. The mixing of chloride aerosols with insoluble substances can inhibit their hygroscopic properties, which in turn affects the cloud condensation nuclei activation and heterogeneous reactivity. The encasing of chloride aerosols within light-absorbing substances changes their optical properties and subsequently causes atmospheric warming. This paper emphasizes the complexity of the mixing of chloride aerosols, as well as the potential atmospheric implications thereof, and proposes some research topics deserving future study.

Abstract  Agricultural landscapes often leak inorganic nitrogen to the stream network, usually in the form of nitrate-nitrite (NOx-N), degrading downstream water quality on both the local and regional scales. While the spatial distribution of nitrate sources has been delineated in many watersheds, less is known about the complicated temporal dynamics that drive stream NOx-N because traditional methods of stream grab sampling are often conducted at a low frequency. Deployment of accurate real-time, continuous measurement devices that have been developed in recent years enables high-frequency sampling that provides detailed information on the concentration-discharge relation and the timing of NOx-N delivery to streams. We aggregated 15-min interval NOx-N and discharge data over a nine-year period into daily averages and then used robust statistical methods to identify how the discharge regime within an artificially-drained agricultural watershed reflected catchment hydrology and NOx-N delivery pathways. We then quantified how transport and supply limitations varied from year-to-year and how dependence of these limitations varied with climate, especially drought. Our results show NOx-N concentrations increased linearly with discharge up to an average "turning point" of 1.42 mm of area-normalized discharge, after which concentrations decline with increasing discharge. We estimate transport and supply limitations to govern 57 and 43 percent, respectively, of the NOx-N flux over the nine-year period. Drought effects on the NOx-N flux linger for multiple years and this is reflected in a greater tendency toward supply limitations in the.three years following drought. How the turning point varies with climate may aid in prediction of NOx-N loading in future climate regimes. (C) 2017 Elsevier B.V. All rights reserved.

Abstract  Sickle cell disease is caused by a mutant form of hemoglobin that polymerizes under hypoxic conditions, increasing rigidity, fragility, calcium influx-mediated dehydration, and adhesivity of red blood cells. Increased red cell fragility results in hemolysis, which reduces nitric oxide (NO) bioavailability, and induces platelet activation and inflammation leading to adhesion of circulating blood cells. Nitric Oxide inhibits adhesion and platelet activation. Nitrite has emerged as an attractive therapeutic agent that targets delivery of NO activity to areas of hypoxia through bioactivation by deoxygenated red blood cell hemoglobin. In this study, we demonstrate anti-platelet activity of nitrite at doses achievable through dietary interventions with comparison to similar doses with other NO donating agents. Unlike other NO donating agents, nitrite activity is shown to be potentiated in the presence of red blood cells in hypoxic conditions. We also show that nitrite reduces calcium associated loss of phospholipid asymmetry that is associated with increased red cell adhesion, and that red cell deformability is also improved. We show that nitrite inhibits red cell adhesion in a microfluidic flow-channel assay after endothelial cell activation. In further investigations, we show that leukocyte and platelet adhesion is blunted in nitrite-fed wild type mice compared to control after either lipopolysaccharide- or hemolysis-induced inflammation. Moreover, we demonstrate that nitrite treatment results in a reduction in adhesion of circulating blood cells and reduced red blood cell hemolysis in humanized transgenic sickle cell mice subjected to local hypoxia. These data suggest that nitrite is an effective anti-platelet and anti-adhesion agent that is activated by red blood cells, with enhanced potency under physiological hypoxia and in venous blood that may be useful therapeutically.

Abstract  Background and Aims: The efficiency of N assimilation in response to defoliation is a critical component of plant regrowth and forage production. The aim of this research was to test the effect of the internal C/N balance on NO3- assimilation and to estimate the associated cytokinin signals following defoliation of perennial ryegrass ( Lolium perenne L. 'Grasslands Nui') plants.

Methods: Plants, manipulated to have contrasting internal N content and contrasting availability of water soluble carbohydrates (WSCs), were obtained by exposure to either continuous light or short days (8:16 h light-dark), and watered with modified N-free Hoagland medium containing either high (5 m m ) or low (50 μ m ) NO3- as sole N source. Half of the plants were defoliated and the root, sheath and leaf tissue were harvested at 8, 24 and 168 h after cutting. The spatiotemporal changes in WSCs, synthesis of amino acids and associated cytokinin content were recorded after cutting.

Key Results: Leaf regrowth following defoliation involved changes in the low- and high-molecular weight WSCs. The extent of the changes and the partitioning of the WSC following defoliation were dependant on the initial WSC levels and the C and N availability. Cytokinin levels varied in the sheath and root as early as 8 h following defoliation and preceded an overall increase in amino acids at 24 h. Subsequently, negative feedback brought the amino acid response back towards pre-defoliation levels within 168 h after cutting, a response that was under control of the C/N ratio.

Conclusions: WSC remobilization in the leaf is coordinated with N availability to the root, potentially via a systemic cytokinin signal, leading to efficient N assimilation in the leaf and the sheath tissues and to early leaf regrowth following defoliation.

Abstract  Worldwide, the standard methods for the determination of the important wastewater parameter chemical oxygen demand (COD) are still based on the use of the hazardous chemicals, mercury sulfate and chromium(VI). However, due to their properties they are meanwhile classified as "priority pollutants" and shall be phased out or banned in the frame of REACH (current European Chemical Law: Registration, Evaluation, Authorization and restriction of Chemicals) by the European Union. Hence, a new wet-chemical method free of mercury and chromium(VI) was developed. Manganese(III) was used as oxidant and silver nitrate for the removal of chloride ions. The quantification was performed by back titration of manganese(III) with iron(II) as done in the standard method. In order to minimize losses of organic substances during the precipitation of silver chloride, suspended and colloid organic matter had to be separated by precipitation of aluminum hydroxide in a first step. In these cases, two fractions, one of the suspended and colloid matters and a second of the dissolved organic substances, are prepared and oxidized separately. The method was tested with potassium hydrogen phthalate (KHP) as conventional COD reference substance and different types of wastewater samples. The oxidation of KHP was reproducible in a COD range of 20-500 mg/L with a mean recovery rate of 88.7% in comparison to the standard COD method (DIN 38409-41). Also in presence of 1000 mg/L chloride a recovery rate of 84.1% was reached. For a series of industrial and municipal wastewater samples a high correlation (R(2) = 0.9935) to the standard method with a mean recovery rate of 78.1% (±5.2%) was determined. Even though the results of the new method are not 100% of the standard method, its high correlation to the standard method and reproducibility offers an environmentally benign alternative method with no need to purchase new laboratory equipment.

Abstract  Manganese spinel ferrite nanoparticles were synthesized by a solvothermal route based on high temperature decomposition of metal nitrates in the presence of different contents of Triethylene glycol. This simple and low cost method can be applied to prepare large quantities of nanoparticles (tens of grams). Powder X-ray diffraction (PXRD) and Transmission Electron Microscopy (TEM) confirmed that nanoparticles with a good crystalline quality were obtained. A good agreement between the average particle size calculated by PXRD and TEM was observed. Fourier-transform infrared spectra showed that polymer molecules have the tendency to form bonds with the surface of ferrite nanoparticles reducing the surface spin disorder, and then enhancing the saturation magnetization (M-s). Therefore, much higher Ms value (up to similar to 91 emu/g at 5 K) was observed compared with that of bare nanoparticles without surfactant. The blocking temperature showed a remarkable shift to lower values with increasing the polymer starting amount. In addition, by increasing the polymer initial content, a more homogeneous size distribution was obtained and the initial strongly interacting superspin glass behavior changed to a weakly interacting superparamagnetic state. (C) 2015 Elsevier B.V. All rights reserved.

Abstract  Molten alkali nitrates are used commercially as thermal storage fluids (HTF) for solar thermal electricity generation. Their range of operation is limited by the thermal stability and this limits the energy (steam-Rankine cycle) efficiency of these processes. In this study, the effect of atmosphere on the thermal stability of nitrates was investigated using simultaneous thermal analysis techniques (STA). The use of oxygen (O-2) as a blanket gas was found to delay the decomposition point of the ternary NaNO3-KNO3-LiNO3 (13.23-57.14-29.63 weight ratio) mixture by 55 degrees C. By which operating range will increase 65 degrees C more compared to the binary solar salt. Higher heating rates increased the decomposition point but had less effect on premelting and melting properties. Nitrogen monoxide, and O-2 evolution after melting indicates concurrent reversible reactions. Similar phenomena were observed for single and binary nitrates. The eutectic melting point of ternary nitrate obtained from the STA agreed well with FactSage eutectic composition prediction.

Abstract  To understand the changes in soil properties and function due to human-induced disruption of mature tropical forest cover in differing climatic zones and forest types, we investigated soil properties and gross soil N dynamics in the top 5 cm of mineral soil in old-growth and young secondary (<30 years) stands of four contrasting forest types (dry dipterocarp, dry evergreen, mixed deciduous, and moist evergreen) in Thailand. In all four forest types, soil total carbon (C) and nitrogen (N) pools were not different between old-growth and young secondary forests. In contrast, soil N turnover rates, such as the gross and net mineralization and nitrification rates, were different depending on forest type (e.g., gross mineralization rate was faster in old-growth than in secondary moist evergreen forest, but faster in secondary than in old-growth for the other three forest types). Although the response of soil N turnover rate to forest succession was inconsistent among the four forest types, the gross nitrification ratio (gross nitrification rate as a proportion of gross mineralization rate) was smaller in secondary than in old-growth forest in all forest types. This shift in the inorganic N production balance by reducing NO3-N production relative to NH4-N production in Southeast Asia warrants further investigation, including the extent of the phenomenon and its effect on plant productivity and species composition. (C) 2017 Elsevier B.V. All rights reserved.

Abstract  A novel high-throughout (HTR) ion-exchange (IEX) resin workflow has been developed for characterizing ion exchange equilibrium of commercial and experimental IEX resins against a range of different applications where water environment differs from site to site. Because of its much higher throughput, design of experiment (DOE) methodology can be easily applied for studying the effects of multiple factors on resin performance. Two case studies will be presented to illustrate the efficacy of the combined HTR workflow and DOE method. In case study one, a series of anion exchange resins have been screened for selective removal of NO3(-) and NO2(-) in water environments consisting of multiple other anions, varied pH, and ionic strength. The response surface model (RSM) is developed to statistically correlate the resin performance with the water composition and predict the best resin candidate. In case study two, the same HTR workflow and DOE method have been applied for screening different cation exchange resins in terms of the selective removal of Mg(2+), Ca(2+), and Ba(2+) from high total dissolved salt (TDS) water. A master DOE model including all of the cation exchange resins is created to predict divalent cation removal by different IEX resins under specific conditions, from which the best resin candidates can be identified. The successful adoption of HTR workflow and DOE method for studying the ion exchange of IEX resins can significantly reduce the resources and time to address industry and application needs.

Abstract  Marichromatium gracile: YL28 (M. gracile YL28) is an anoxygenic phototrophic bacterial strain that utilizes ammonia, nitrate, or nitrite as its sole nitrogen source during growth. In this study, we investigated the removal and transformation of ammonium, nitrate, and nitrite by M. gracile YL28 grown in a combinatorial culture system of sodium acetate-ammonium, sodium acetate-nitrate and sodium acetate-nitrite in response to different initial dissolved oxygen (DO) levels. In the sodium acetate-ammonium system under aerobic conditions (initial DO = 7.20-7.25 mg/L), we detected a continuous accumulation of nitrate and nitrite. However, under semi-anaerobic conditions (initial DO = 4.08-4.26 mg/L), we observed a temporary accumulation of nitrate and nitrite. Interestingly, under anaerobic conditions (initial DO = 0.36-0.67 mg/L), there was little accumulation of nitrate and nitrite, but an increase in nitrous oxide production. In the sodium acetate-nitrite system, nitrite levels declined slightly under aerobic conditions, and nitrite was completely removed under semi-anaerobic and anaerobic conditions. In addition, M. gracile YL28 was able to grow using nitrite as the sole nitrogen source in situations when nitrogen gas produced by denitrification was eliminated. Taken together, the data indicate that M. gracile YL28 performs simultaneous heterotrophic nitrification and denitrification at low-DO levels and uses nitrite as the sole nitrogen source for growth. Our study is the first to demonstrate that anoxygenic phototrophic bacteria perform heterotrophic ammonia-oxidization and denitrification under anaerobic conditions.

Abstract  Several bimetallic NiAg catalysts for the lignin hydrogenolysis reaction are evaluated. NiAg catalysts are either prepared by wet chemical reduction, in which a mixture of AgNO3 and Ni(NO3)(2) or a mixture of AgOAc and Ni(OAc)(2) is reduced by NaBH4 and stabilized by polyvinylpyrrolidone in water, or by the decomposition-precipitation method to obtain NiAg/SiO2. These three catalysts exhibit distinct performances in hydrogenolysis of a lignin -O-4 model compound. For colloidal catalyst from co-reduction of AgOAc and Ni(OAc)(2), separate growths of Ag and Ni nanoparticles (NPs) are observed, and the system exhibits an undesired selectivity of 31.5% toward dimer products. On the other hand, NiAg NPs are dominant after the reduction of nitrate precursors, although the NP size is not sufficiently small (6.7 nm), resulting in high selectivity but a low reaction rate (12.6% conversion with 12.1% monomers yield). Bimetallic NiAg active phase with excellent dispersion (approximate to 1.5 nm) is obtained on NiAg/SiO2, which enables 72.7% substrate conversion and 65.6% yield of target monomer compounds. From these results, NiAg bimetallic catalyst is indeed superior to monometallic Ni in lignin hydrogenolysis, however, the formation of bimetallic NiAg catalyst is highly sensitive to the preparation conditionsproper selection of precursors, reductant, and support/stabilizer are all crucial.