How are soil use and management reflected by soil organic matter characteristics: a spectroscopic approach

We studied the quantitative and qualitative changes of soil organic matter (SOM) due to different land uses (arable versus grassland) and treatments (organic manure and mineral fertilizer) within an agricultural crop rotation in a long-term field experiment, conducted since 1956 at Ultuna, Sweden, on a Eutric Cambisol. The organic carbon (OC) content of the grassland plot was 1.8 times greater than that of the similarly fertilized Ca(NO3) 2 treated cropped plots. The comparison of two dispersion techniques (a lowenergy sonication and a chemical dispersion which yield inherent soil aggregates) showed that increasing OC contents of the silt-sized fractions were not matched by a linear increase of silt-sized aggregates. This indicated saturation of the aggregates with OC and a limited capacity of particles to protect OC physically. Thermogravimetric analyses suggested an increase of free organic matter with increasing OC contents. Transmission FT-IR spectroscopy showed relative enrichment of carboxylic, aromatic, CH and NH groups in plots with increasing OC contents. The silt-sized fractions contained the largest SOM pool and, as revealed by 13C NMR spectroscopy, were qualitatively more influenced by the plant residue versus manure input than the clay fractions. Alkyl and O-alkyl C in the silt-sized fractions amounted to 57.4% of organic carbon in the animal manure treated plots and 50–53% in the other treatments.We thank the Austrian Science Fund (Fonds zur FÖrderung der wissenschaftlichen Forschung) for funding this bilateral project.Peer reviewe

Life cycle modelling of environmental impacts of application of processed organic municipal solid waste on agricultural land (EASEWASTE)

A model capable of quantifying the potential environmental impacts of agricultural application of composted or anaerobically digested source-separated organic municipal solid waste (MSW) is presented. In addition to the direct impacts, the model accounts for savings by avoiding the production and use of commercial fertilizers. The model is part of a larger model, Environmental Assessment of Solid Waste Systems and Technology (EASEWASTE), developed as a decisionsupport model, focusing on assessment of alternative waste management options. The environmental impacts of the land application of processed organic waste are quantified by emission coefficients referring to the composition of the processed waste and related to specific crop rotation as well as soil type. The model contains several default parameters based on literature data, field experiments and modelling by the agro-ecosystem model, Daisy. All data can be modified by the user allowing application of the model to other situations. A case study including four scenarios was performed to illustrate the use of the model. One tonne of nitrogen in composted and anaerobically digested MSW was applied as fertilizer to loamy and sandy soil at a plant farm in western Denmark. Application of the processed organic waste mainly affected the environmental impact categories global warming (0.4–0.7 PE), acidification (–0.06 (saving)–1.6 PE), nutrient enrichment (–1.0 (saving)–3.1 PE), and toxicity. The main contributors to these categories were nitrous oxide formation (global warming), ammonia volatilization (acidification and nutrient enrichment), nitrate losses (nutrient enrichment and groundwater contamination), and heavy metal input to soil (toxicity potentials). The local agricultural conditions as well as the composition of the processed MSW showed large influence on the environmental impacts. A range of benefits, mainly related to improved soil quality from long-term application of the processed organic waste, could not be generally quantified with respect to the chosen life cycle assessment impact categories and were therefore not included in the model. These effects should be considered in conjunction with the results of the life cycle assessment

Persistent order due to transiently enhanced nesting in an electronically excited charge density wave

Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time- and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of the dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. Our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order

Citalopram Enhances the Activity of Chloroquine in Resistant Plasmodium in Vitro and in Vivo 1

ABSTRACT Citalopram, is an extremely potent inhibitor of neuronal serotonin reuptake. It is structurally unrelated to other antidepressants, but it contains the chemical features associated with reversal of drug resistance and exhibits minimal cardiotoxic side effects and fewer of the anticholinergic and adrenolytic side effects associated with other psychotropic agents. Sensitivity tests to citalopram alone and in combination with chloroquine were performed against chloroquine-resistant and chloroquine-sensitive strains of Plasmodium falciparum and Plasmodium chabaudi. Citalopram alone showed intrinsic activity against the chloroquine-resistant strains of P. falciparum (IC 50 ϭ 1.51 Ϯ .6 M) but only limited activity against the chloroquine-sensitive strain (IC 50 ϭ 33.27 Ϯ 5.87 M) and no activity in vivo. The interaction of chloroquine and citalopram in vitro resulted in a synergistic response in the chloroquineresistant strain but there was no interaction between the drugs in the chloroquine-sensitive strain-a pattern found with other reversal agents. Citalopram enhanced chloroquine susceptibility in both strains of P. chabaudi, however, the potentiating effect was seen at lower doses in the chloroquine-resistant strain. The results of this study suggest that citalopram may have potential as a chemosensitizer in Plasmodium infections on the basis of the low toxicity of citalopram at concentrations potentiating chloroquine activity both in vitro and in vivo. Malaria is a significant source of global morbidity and mortality. Despite the development of new antimalarial agents such as mefloquine, halofantrine and the artemisins, chloroquine remains the drug of choice for the treatment of uncomplicated Plasmodium falciparum malaria infections, due to its low cost, rapid onset of action and its low toxicity. However, the efficacy of chloroquine has diminished due to the emergence and prevalence of chloroquine-resistant strains of P. falciparum (Wensdorfer and Payne, 1991). The rapid development and spread of resistance to chloroquine and other antimalarials, and the tremendous cost of drug development has emphasized the necessity to optimize the use of existing antimalarial agents A number of adjunct drugs have been identified from a wide variety of chemical classes including calcium-channel blockers Citalopram,1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)-1,3dihydroisobenzofuran-5-carbonite), is an extremely potent inhibitor of neuronal serotonin reuptake The low toxicity coupled with the chemical similarity to chemosensitizers (resistance reversal agents) prompted us to investigate the chemosensitizing effect of citalopram in Plasmodium. In this study, we screened citalopram for chloroquine potentiating activity in chloroquine-resistant and chloroquine sensitive-parasites; both in vitro against P. falciparum and in a rodent malaria model (Plasmodium chabaudi). Methods Effect of Citalopram in Vitro Parasites. Two well-characterized isolates of P. falciparum were used for the drug assays. The chloroquine-resistant FCR-3 strain (IC 50 ϳ 150 nM) (donated by J. Freese, Research in diseases of the Tropical Environment, Durban, South Africa) and the chloroquine