79 research outputs found

    Ionization energies in solution with the QM : QM approach

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    We discuss a fragment-based QM:QM scheme as a practical way to access the energetics of vertical electronic processes in the condensed phase. In the QM:QM scheme, we decompose the large molecular system into small fragments, which interact solely electrostatically. The energies of the fragments are calculated in a self-consistent field generated by the other fragments and the total energy of the system is calculated as a sum of the fragment energies. We show on two test cases (cytosine and a sodium cation) that the method allows one to accurately simulate the shift of vertical ionization energies (VIE) while going from the gas phase to the bulk. For both examples, the predicted solvent shifts and peak widths estimated at the DFT level agree well with the experimental observations. We argue that the QM:QM approach is more suitable than either an electrostatic embedding based QM/MM approach, a full quantum description at the DFT level with a generally used functional or a combination of both. We also discuss the potential scope of the applicability for other electronic processes such as Auger decay.Peer reviewe

    Impact of Soil Sealing on Soil Carbon Sequestration, Water Storage Potentials and Biomass Productivity in Functional Urban Areas of the European Union and the United Kingdom

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    The negative impacts of soil sealing are numerous, from withdrawing fertile soil from biomass production to modifying the microclimate and decreasing biodiversity. Many of the processes are interrelated and propagate further undesirable consequences from local to global levels. Three issues are especially important from the viewpoint of multiscale ecological cycles and consequent environmental impacts. One is soil organic carbon (SOC), the other is soil water management and the third is biomass productivity. In this study, we assessed the lost carbon sequestration potential due to soil sealing in functional Urban Areas (FUAs) of Europe, the potential effect of soil sealing on the topsoil to hold water to its full capacity and the loss of biomass productivity potential. Findings revealed that one-fifth of the area of soil that became sealed between 2012 and 2018 was of high productivity potential, and almost two-thirds was of medium productivity potential. New soil sealing caused a loss of carbon sequestration potential estimated at 4 million tons of carbon of the FUAs and also caused an estimated potential loss of water-holding capacity of 668 million m3

    Changing patterns of allotment gardening in the Czech Republic and Slovakia

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    Allotment gardens have played a significant role in Czech and Slovak society for decades, building upon a rich history of gardening. This article elaborates on Czech and Slovak allotments in the European context and identifies their core functions, services, and benefits. We provide a thorough historical review of allotments in this region, reaching back to the eighteenth century to trace significant periods and historic events that shaped society in general and urban gardening in particular. We analyze the development of allotments until and after 1989 and illustrate key aspects of their present situation using case studies and examples. The article provides a complex historical narrative as a good basis for discussions on contemporary trends, challenges, and visions for the future of urban allotment gardening in both countries

    Longitudinal Volumetric Assessment of Ventricular Enlargement in Pet Dogs Trained for Functional Magnetic Resonance Imaging (fMRI) Studies

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    Background: Recent studies suggest that clinically sound ventriculomegaly in dogs could be a preliminary form of the clinically significant hydrocephalus. We evaluated changes of ventricular volumes in awake functional magnetic resonance imaging (fMRI) trained dogs with indirectly assessed cognitive abilities over time (thus avoiding the use of anaesthetics, which can alter the pressure). Our research question was whether ventricular enlargement developing over time would have any detrimental effect on staying still while being scanned; which can be extrapolated to the ability to pay attention and to exert inhibition. Methods: Seven healthy dogs, 2–8 years old at the baseline scan and 4 years older at rescan, participated in a rigorous and gradual training for staying motionless (<2 mm) in the magnetic resonance (MR) scanner without any sedation during 6 minute-long structural MR sequences. On T1 structural images, volumetric analyses of the lateral ventricles were completed by software guided semi-automated tissue-type segmentations performed with FMRIB Software Library (FSL, Analysis Group, Oxford, UK). Results and conclusion: We report significant enlargement for both ventricles (left: 47.46 %, right: 46.07 %) over time while dogs retained high levels of attention and inhibition. The results suggest that even considerable ventricular enlargement arising during normal aging does not necessarily reflect observable pathological changes in behavior

    Identification of Small Molecule Inhibitors of Tau Aggregation by Targeting Monomeric Tau As a Potential Therapeutic Approach for Tauopathies.

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    A potential strategy to alleviate the aggregation of intrinsically disordered proteins (IDPs) is to maintain the native functional state of the protein by small molecule binding. However, the targeting of the native state of IDPs by small molecules has been challenging due to their heterogeneous conformational ensembles. To tackle this challenge, we applied a high-throughput chemical microarray surface plasmon resonance imaging screen to detect the binding between small molecules and monomeric full-length Tau, a protein linked with the onset of a range of Tauopathies. The screen identified a novel set of drug-like fragment and lead-like compounds that bound to Tau. We verified that the majority of these hit compounds reduced the aggregation of different Tau constructs in vitro and in N2a cells. These results demonstrate that Tau is a viable receptor of drug-like small molecules. The drug discovery approach that we present can be applied to other IDPs linked to other misfolding diseases such as Alzheimer's and Parkinson's diseases.We thank the Wellcome Trust (UK), Medical Research Council (UK), Elan Pharmaceuticals (USA), the Canadian Institutes of Health Research (Canada) and the Alzheimer Society of Ontario (Canada), and Hungarian Brain Research Program (KTIA_NAP_13-2014-0009) for funding.This is the author accepted manuscript. The final version is available from Bentham Science via http://dx.doi.org/10.2174/15672050120915101910495

    Garlic (<em>Allium sativum</em> L.): Characterization of Bioactive Compounds and Related Health Benefits

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    Garlic (Allium sativum L.) is one of the greatest gifts of natural medicine and the oldest medicinal herbs that is cultivated all over the world. It is a widely used spice plant with well-known medicinal properties. Garlic is an important raw material of plant origin with observed and proven positive effects on the human body. A. sativum L. belongs to the most extensively studied medicinal herbs from genus Allium. In the past few decades, its biologically active compounds have been analyzed for their therapeutical properties. The most essential biologically active compound discovered in A. sativum is allicin, working synergistically with other phytochemicals in the prevention of many diseases. Preparation of garlic extractions can be done in liquid form and solid form. The composition and bioactivity of the extraction depend on the strain, age, method of preparation, and consumption method. When extracted and isolated, the bioactive compounds of garlic show a wide range of beneficial health effects: platelets inhibitory and antithrombic activities, hepatoprotective, antimicrobial, antihyperglycemic, antidiabetic, and antitumor. The present chapter describes botanical characterization of garlic, its chemical composition regarding bioactive compounds, and its health benefits

    A reduced-function allele reveals that EARLY FLOWERING3 repressive action on the circadian clock is modulated by phytochrome signals in Arabidopsis

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    Arabidopsis thaliana EARLY FLOWERING3 (ELF3) is essential for the generation of circadian rhythms. ELF3 has been proposed to restrict light signals to the oscillator through phytochrome photoreceptors, but that has not been explicitly shown. Furthermore, the genetic action of ELF3 within the clock had remained elusive. Here, we report a functional characterization of ELF3 through the analysis of the elf3-12 allele, which encodes an amino acid replacement in a conserved domain. Circadian oscillations persisted, and unlike elf3 null alleles, elf3-12 resulted in a short circadian period only under ambient light. The period shortening effect of elf3-12 was enhanced by the overexpression of phytochromes phyA and phyB. We found that elf3-12 was only modestly perturbed in resetting of the oscillator and in gating light-regulated gene expression. Furthermore, elf3-12 essentially displayed wild-type development. We identified targets of ELF3 transcriptional repression in the oscillator, highlighting the action at the morning gene PSEUDO-RESPONSE REGULATOR9. Taken together, we identified two separable roles for ELF3, one affecting the circadian network and the other affecting light input to the oscillator. This is consistent with a dual function of ELF3 as both an integrator of phytochrome signals and a repressor component of the core oscillator
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