117 research outputs found

    Direct  Energy Production From Hydrogen Sulfide in Black Sea Water - Electrochemical Study

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    A sulfide driven fuel cell is proposed to clean the Black Sea with the simultaneous A sulfide driven fuel cell is proposed to clean the Black Sea with the simultaneous production of energy. The process is hopeful even at low sulfide concentrations, i.e.10 to 25 mg/l being close to the ones in the Black Sea water. The main problem for the practical application of this type of fuel cell are the low current and power densities. The measurement of the generated electric current compared to the sulfide depletion show that the most probable anode reaction is oxidation of sulfide to sulfate. It is evident that parasite competitive reactions oxidation of sulfide occurs in the anode compartment of the fuel cell. The pH measurements shows that the transfer of hydroxylic anions from the cathodic compartment to the anodic one across the separating membrane is not fast enough to compensate its drop in the anode compartment

    Chern - Simons Gauge Field Theory of Two - Dimensional Ferromagnets

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    A Chern-Simons gauged Nonlinear Schr\"odinger Equation is derived from the continuous Heisenberg model in 2+1 dimensions. The corresponding planar magnets can be analyzed whithin the anyon theory. Thus, we show that static magnetic vortices correspond to the self-dual Chern - Simons solitons and are described by the Liouville equation. The related magnetic topological charge is associated with the electric charge of anyons. Furthermore, vortex - antivortex configurations are described by the sinh-Gordon equation and its conformally invariant extension. Physical consequences of these results are discussed.Comment: 15 pages, Plain TeX, Lecce, June 199

    Pilot study of transcranial photobiomodulation of lymphatic clearance of beta-amyloid from the mouse brain: breakthrough strategies for non-pharmacologic therapy of Alzheimer's disease

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    In this pilot study, we analyzed effects of transcranial photobiomodulation (tPBM, 1267 nm, 32 J/cm2) on clearance of beta-amyloid (Aβ) from the mouse brain. The immunohistochemical and confocal data clearly demonstrate the significant reduction of deposition of Aβ plaques in mice after tPBM vs. untreated animals. The behavior tests showed that tPBM improved the cognitive, memory and neurological status of mice with Alzheimer’s disease (AD). Using of our original method based on optical coherence tomography (OCT) analysis of clearance of gold nanorods (GNRs) from the brain, we proposed possible mechanism underlying tPBM-stimulating effects on clearance of Aβ via the lymphatic system of the brain and the neck. These results open breakthrough strategies for a non-pharmacological therapy of Alzheimer’s disease and clearly demonstrate that tPBM might be a promising therapeutic target for preventing or delaying Alzheimer’s disease

    Complex networks theory for analyzing metabolic networks

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    One of the main tasks of post-genomic informatics is to systematically investigate all molecules and their interactions within a living cell so as to understand how these molecules and the interactions between them relate to the function of the organism, while networks are appropriate abstract description of all kinds of interactions. In the past few years, great achievement has been made in developing theory of complex networks for revealing the organizing principles that govern the formation and evolution of various complex biological, technological and social networks. This paper reviews the accomplishments in constructing genome-based metabolic networks and describes how the theory of complex networks is applied to analyze metabolic networks.Comment: 13 pages, 2 figure

    Discovery of potent, novel, non-toxic anti-malarial compounds via quantum modelling, virtual screening and in vitro experimental validation

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    <p>Abstract</p> <p>Background</p> <p>Developing resistance towards existing anti-malarial therapies emphasize the urgent need for new therapeutic options. Additionally, many malaria drugs in use today have high toxicity and low therapeutic indices. Gradient Biomodeling, LLC has developed a quantum-model search technology that uses quantum similarity and does not depend explicitly on chemical structure, as molecules are rigorously described in fundamental quantum attributes related to individual pharmacological properties. Therapeutic activity, as well as toxicity and other essential properties can be analysed and optimized simultaneously, independently of one another. Such methodology is suitable for a search of novel, non-toxic, active anti-malarial compounds.</p> <p>Methods</p> <p>A set of innovative algorithms is used for the fast calculation and interpretation of electron-density attributes of molecular structures at the quantum level for rapid discovery of prospective pharmaceuticals. Potency and efficacy, as well as additional physicochemical, metabolic, pharmacokinetic, safety, permeability and other properties were characterized by the procedure. Once quantum models are developed and experimentally validated, the methodology provides a straightforward implementation for lead discovery, compound optimizzation and <it>de novo </it>molecular design.</p> <p>Results</p> <p>Starting with a diverse training set of 26 well-known anti-malarial agents combined with 1730 moderately active and inactive molecules, novel compounds that have strong anti-malarial activity, low cytotoxicity and structural dissimilarity from the training set were discovered and experimentally validated. Twelve compounds were identified <it>in silico </it>and tested <it>in vitro</it>; eight of them showed anti-malarial activity (IC50 ≤ 10 μM), with six being very effective (IC50 ≤ 1 μM), and four exhibiting low nanomolar potency. The most active compounds were also tested for mammalian cytotoxicity and found to be non-toxic, with a therapeutic index of more than 6,900 for the most active compound.</p> <p>Conclusions</p> <p>Gradient's metric modelling approach and electron-density molecular representations can be powerful tools in the discovery and design of novel anti-malarial compounds. Since the quantum models are agnostic of the particular biological target, the technology can account for different mechanisms of action and be used for <it>de novo </it>design of small molecules with activity against not only the asexual phase of the malaria parasite, but also against the liver stage of the parasite development, which may lead to true causal prophylaxis.</p

    An Allosteric Mechanism for Switching between Parallel Tracks in Mammalian Sulfur Metabolism

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    Methionine (Met) is an essential amino acid that is needed for the synthesis of S-adenosylmethionine (AdoMet), the major biological methylating agent. Methionine used for AdoMet synthesis can be replenished via remethylation of homocysteine. Alternatively, homocysteine can be converted to cysteine via the transsulfuration pathway. Aberrations in methionine metabolism are associated with a number of complex diseases, including cancer, anemia, and neurodegenerative diseases. The concentration of methionine in blood and in organs is tightly regulated. Liver plays a key role in buffering blood methionine levels, and an interesting feature of its metabolism is that parallel tracks exist for the synthesis and utilization of AdoMet. To elucidate the molecular mechanism that controls metabolic fluxes in liver methionine metabolism, we have studied the dependencies of AdoMet concentration and methionine consumption rate on methionine concentration in native murine hepatocytes at physiologically relevant concentrations (40–400 µM). We find that both [AdoMet] and methionine consumption rates do not change gradually with an increase in [Met] but rise sharply (∼10-fold) in the narrow Met interval from 50 to 100 µM. Analysis of our experimental data using a mathematical model reveals that the sharp increase in [AdoMet] and the methionine consumption rate observed within the trigger zone are associated with metabolic switching from methionine conservation to disposal, regulated allosterically by switching between parallel pathways. This regulatory switch is triggered by [Met] and provides a mechanism for stabilization of methionine levels in blood over wide variations in dietary methionine intake

    Observation of BD()KKS0{B\to D^{(*)} K^- K^{0}_S} decays using the 2019-2022 Belle II data sample

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    We present a measurement of the branching fractions of four B0,D()+,0KKS0B^{0,-}\to D^{(*)+,0} K^- K^{0}_S decay modes. The measurement is based on data from SuperKEKB electron-positron collisions at the Υ(4S)\Upsilon(4S) resonance collected with the Belle II detector and corresponding to an integrated luminosity of 362 fb1{362~\text{fb}^{-1}}. The event yields are extracted from fits to the distributions of the difference between expected and observed BB meson energy to separate signal and background, and are efficiency-corrected as a function of the invariant mass of the KKS0K^-K_S^0 system. We find the branching fractions to be: B(BD0KKS0)=(1.89±0.16±0.10)×104, \text{B}(B^-\to D^0K^-K_S^0)=(1.89\pm 0.16\pm 0.10)\times 10^{-4}, B(B0D+KKS0)=(0.85±0.11±0.05)×104, \text{B}(\overline B{}^0\to D^+K^-K_S^0)=(0.85\pm 0.11\pm 0.05)\times 10^{-4}, B(BD0KKS0)=(1.57±0.27±0.12)×104, \text{B}(B^-\to D^{*0}K^-K_S^0)=(1.57\pm 0.27\pm 0.12)\times 10^{-4}, B(B0D+KKS0)=(0.96±0.18±0.06)×104, \text{B}(\overline B{}^0\to D^{*+}K^-K_S^0)=(0.96\pm 0.18\pm 0.06)\times 10^{-4}, where the first uncertainty is statistical and the second systematic. These results include the first observation of B0D+KKS0\overline B{}^0\to D^+K^-K_S^0, BD0KKS0B^-\to D^{*0}K^-K_S^0, and B0D+KKS0\overline B{}^0\to D^{*+}K^-K_S^0 decays and a significant improvement in the precision of B(BD0KKS0)\text{B}(B^-\to D^0K^-K_S^0) compared to previous measurements

    Tests of light-lepton universality in angular asymmetries of B0DνB^0 \to D^{*-} \ell \nu decays

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    We present the first comprehensive tests of light-lepton universality in the angular distributions of semileptonic \Bz-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral \B is fully reconstructed in \PUpsilonFourS{} \to\B\overline{B} decays in data corresponding to \lumion integrated luminosity from electron-positron collisions collected with the \belletwo detector. We find no significant deviation from the standard model expectations

    Measurement of CPCP asymmetries in B0ϕKS0B^0\to \phi K^0_S decays with Belle II

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    We present a measurement of time-dependent rate asymmetries in B0ϕKS0B^0\to \phi K^0_S decays to search for non-standard-model physics in bqqsb\to q \overline{q}s transitions. The data sample is collected with the Belle II detector at the SuperKEKB asymmetric-energy e+ee^{+}e^{-} collider in 2019-2022 and contains (387±6)×106(387\pm 6)\times 10^6 bottom-antibottom mesons from Υ(4S)\Upsilon(4S) resonance decays. We reconstruct 162±17162\pm17 signal events and extract the charge-parity (CPCP) violating parameters from a fit to the distribution of the proper-decay-time difference of the two BB mesons. The measured direct and mixing-induced CPCP asymmetries are A=0.31±0.20±0.05A=0.31\pm0.20\pm0.05 and S=0.54±0.260.08+0.06S=0.54\pm0.26^{+0.06}_{-0.08}, respectively, where the first uncertainties are statistical and the second are systematic. The results are compatible with the CPCP asymmetries observed in bccsb\to c\overline{c} s transitions
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