Исследование алгоритмов логического вывода

Decision support systems give an opportunity to «ascertained« information outputappropriate of user needs.SemanticV1.5beta package meant for representation and visualization knowledge by way of semantic network, as well as access to knowledge base on the graphical interface and query language.This article gives information about test and performance of indexing approach facts, realizedin SemanticV1.5beta

Pulsed magnetic resonance to signal‐enhance metabolites within seconds by utilizing para‐hydrogen

Diseases such as Alzheimer's and cancer have been linked to metabolic dysfunctions, and further understanding of metabolic pathways raises hope to develop cures for such diseases. To broaden the knowledge of metabolisms in vitro and in vivo, methods are desirable for direct probing of metabolic function. Here, we are introducing a pulsed nuclear magnetic resonance (NMR) approach to generate hyperpolarized metabolites within seconds, which act as metabolism probes. Hyperpolarization represents a magnetic resonance technique to enhance signals by over 10 000‐fold. We accomplished an efficient metabolite hyperpolarization by developing an isotopic labeling strategy for generating precursors containing a favorable nuclear spin system to add para‐hydrogen and convert its two‐spin longitudinal order into enhanced metabolite signals. The transfer is performed by an invented NMR experiment and 20 000‐fold signal enhancements are achieved. Our technique provides a fast way of generating hyperpolarized metabolites by using para‐hydrogen directly in a high magnetic field without the need for field cycling

A Field-Independent Method for the Rapid Generation of Hyperpolarized [1-13C]Pyruvate in Clean Water Solutions for Biomedical Applications

Hyperpolarization methods in magnetic resonance enhance the signals by several orders of magnitude, opening new windows for real-time investigations of dynamic processes in vitro and in vivo. Here, we propose a field-independent para-hydrogen-based pulsed method to produce rapidly hyperpolarized 13C-labeled substrates. We demonstrate the method by polarizing the carboxylic carbon of the pyruvate moiety in a purposely designed precursor to 24 % at ≈22 mT. Following a fast purification procedure, we measure 8 % polarization on free [1-13C]pyruvate in clean water solutions at physiological conditions at 7 T. The enhanced signals allow real-time monitoring of the pyruvate-lactate conversion in cancer cells, demonstrating the potential of the method for biomedical applications in combination with existing or developing magnetic resonance technologies

Bimodal Fluorescence/Magnetic Resonance Molecular Probes with Extended Spin Lifetimes

Bimodal molecular probes combining nuclear magnetic resonance (NMR) and fluorescence have been widely studied in basic science, as well as clinical research. The investigation of spin phenomena holds promise to broaden the scope of available probes allowing deeper insights into physiological processes. Herein, a class of molecules with a bimodal character with respect to fluorescence and nuclear spin singlet states is introduced. Singlet states are NMR silent but can be probed indirectly. Symmetric, perdeuterated molecules, in which the singlet states can be populated by vanishingly small electron-mediated couplings (below 1 Hz) are reported. The lifetimes of these states are an order of magnitude longer than the longitudinal relaxation times and up to four minutes at 7 T. Moreover, these molecules show either aggregation induced emission (AIE) or aggregation caused quenching (ACQ) with respect to their fluorescence. In the latter case, the existence of excited dimers, which are proposed to use in a switchable manner in combination with the quenching of nuclear spin singlet states, is observe

A field‐independent method for the rapid generation of hyperpolarized [1‐13C]Pyruvate in clean water solutions for biomedical applications

Hyperpolarization methods in magnetic resonance enhance the signals by several orders of magnitude, opening new windows for real-time investigations of dynamic processes in vitro and in vivo. Here, we propose a field-independent para-hydrogen-based pulsed method to produce rapidly hyperpolarized 13C-labeled substrates. We demonstrate the method by polarizing the carboxylic carbon of the pyruvate moiety in a purposely designed precursor to 24 % at ≈22 mT. Following a fast purification procedure, we measure 8 % polarization on free [1-13C]pyruvate in clean water solutions at physiological conditions at 7 T. The enhanced signals allow real-time monitoring of the pyruvate-lactate conversion in cancer cells, demonstrating the potential of the method for biomedical applications in combination with existing or developing magnetic resonance technologies

Analysis and prediction of copper surface roughness obtained by selective laser melting

The paper presents the results of experimental studies of the effect of mechanoactivation of the powder, argon shielding gas and the effect of technological modes of melting: the speed of the laser beam, the power of laser radiation, the scanning step, the preliminary temperature of heating the powder material on the surface roughness of the copper powder material obtained by selective laser melting. Experiments on the melting of copper powder are implemented on the installation of layer-by-layer laser melting of the original design, which allows to adjust all technological modes of melting. The surface roughness is determined on the non-contact digital microscope Olympus LEXT OLS4100. The mathematical dependence of the surface layer roughness of copper powder on the technological modes of melting is obtained on the basis of the theory of experiment planning and static processing of the results. The significant parameters of the regime-the power of laser radiation, the speed of the laser beam, the scanning step affecting the roughness of the layer. The positive effect of mechanical activation of powder material and protective atmosphere on the quality of the surface layer is shown

A nanoparticle catalyst for heterogeneous phase para-hydrogen-induced polarization in water.

Para-hydrogen-induced polarization (PHIP) is a technique capable of producing spin polarization at a magnitude far greater than state-of-the-art magnets. A significant application of PHIP is to generate contrast agents for biomedical imaging. Clinically viable and effective contrast agents not only require high levels of polarization but heterogeneous catalysts that can be used in water to eliminate the toxicity impact. Herein, we demonstrate the use of Pt nanoparticles capped with glutathione to induce heterogeneous PHIP in water. The ligand-inhibited surface diffusion on the nanoparticles resulted in a (1) H polarization of P=0.25% for hydroxyethyl propionate, a known contrast agent for magnetic resonance angiography. Transferring the (1) H polarization to a (13) C nucleus using a para-hydrogen polarizer yielded a polarization of 0.013%. The nuclear-spin polarizations achieved in these experiments are the first reported to date involving heterogeneous reactions in water

Development of a position-sensitive detector for positronium inertial sensing measurements

In the last twenty years, both free fall and interferometry/deflectometry experiments have been proposed for the measurement of the gravitational acceleration on positronium, which is a purely leptonic matter-antimatter atom formed by an electron and its antiparticle (positron). Among the several challenges posed by these experiments is the development of position-sensitive detectors to measure the deflection of positronium in the Earth's gravitational field. In this work, we describe our recent progress in the development of position-sensitive detectors. Two different detection schemes are considered. The first is based on Ps ionization in a strong homogeneous magnetic field and imaging of the freed positron with a microchannel plate. The second scheme is based on scanning the positronium atom distribution on a plane by moving the slit or a material grating with sub-nm accuracy, and counting the atoms crossing the obstacle and those annihilating on it. The possibility of reaching a spatial resolution of around 15 μm using the former detection scheme is shown, and preliminary steps towards the development of a detector following the latter scheme (with potential position sensitivity in the sub-nm range) are described