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Showing papers on "NQS published in 2018"


Journal ArticleDOI
TL;DR: In this paper, Carleo and Troyer introduced a new type sampleable ansatz called neural-network quantum states (NQS) that are inspired by the restricted Boltzmann model used in machine learning.
Abstract: Correlator product states (CPS) are a powerful and very broad class of states for quantum lattice systems whose amplitudes can be sampled exactly and efficiently. They work by gluing together states of overlapping clusters of sites on the lattice, called correlators. Recently Carleo and Troyer Science 355, 602 (2017) introduced a new type sampleable ansatz called neural-network quantum states (NQS) that are inspired by the restricted Boltzmann model used in machine learning. By employing the formalism of tensor networks we show that NQS are a special form of CPS with novel properties. Diagramatically a number of simple observations become transparent. Namely, that NQS are CPS built from extensively sized GHZ-form correlators, which are related to a canonical polyadic decomposition of a tensor, making them uniquely unbiased geometrically. Another immediate implication of the equivalence to CPS is that we are able to formulate exact NQS representations for a wide range of paradigmatic states, including superposition of weighed-graph states, the Laughlin state, toric code states, and the resonating valence bond state. These examples reveal the potential of using higher dimensional hidden units and a second hidden layer in NQS. The major outlook of this study is the elevation of NQS to correlator operators allowing them to enhance conventional well-established variational Monte Carlo approaches for strongly correlated fermions.

69 citations


Journal ArticleDOI
TL;DR: In this paper, a natural mineral, such as quartz sand (NQS), was modified with a small amount of goethite to yield a Goethite-coated Quartz sand (GCQS) adsorbent that was used for depolluting water contaminated with a series of phenolic acids that have various numbers and positions of hydroxyl groups in the benzene ring.

20 citations


Journal ArticleDOI
TL;DR: The described approach, based on the synergistic interaction between the above mentioned agents enables a reduction of their effective doses, thus significantly reducing cytotoxic effect of NQs toward eukaryotic HaCaT cells.
Abstract: Staphylococcus aureus is a human pathogen responsible for many antibiotic-resistant infections, for instance burn wound infections, which pose a threat to human life. Exploring possible synergy between various antimicrobial agents, like nanoparticles and plant natural products, may provide new weapons to combat antibiotic resistant pathogens. The objective of this study was to examine the potential of silver nanoparticles (AgNPs) to enhance the antimicrobial activity of selected naphthoquinones (NQs): plumbagin (PL), ramentaceone (RAM), droserone (DR), and 3-chloroplumbagin (3ChPL). We also attempted to elucidate the mechanism by which the AgNPs enhance the antimicrobial activity of NQs. We analyzed the interaction of AgNPs with bacterial membrane and its effect on membrane stability (TEM analysis, staining with SYTO9 and propidium iodide), as well as aggregation of NQs on the surface of nanoparticles (UV-Vis spectroscopy and DLS analysis). Our results demonstrated clearly a synergistic activity of AgNPs and three out of four tested NQs (FBC indexes ≤ 0.375). This resulted in an increase in their combined bactericidal effect toward the S. aureus reference strain and the clinical isolates, which varied in resistance profiles. The synergistic effect (FBC index = 0.375) resulting from combining 3ChPL with silver nitrate used as a control, emphasized the role of the ionic form of silver released from nanoparticles in their bactericidal activity in combination with NQs. The role of membrane damage and AgNPs-NQ interactions in the observed synergy of silver nanoparticles and NQs was also confirmed. Moreover, the described approach, based on the synergistic interaction between the above mentioned agents enables a reduction of their effective doses, thus significantly reducing cytotoxic effect of NQs toward eukaryotic HaCaT cells. Therefore, the present study on the use of a combination of agents (AgNPs-NQs) suggests its potential use as a possible strategy to combat antibiotic-resistant S. aureus.

19 citations


Journal ArticleDOI
TL;DR: In this paper, a simple and sensitive cholylglycine (CG) electrochemical sensor was prepared based on the specific recognition of 1, 2-naphthoquinone-4-sulphonic acid sodium salt (NQS) to CG for the first time.
Abstract: In this paper, a novel, simple and sensitive cholylglycine (CG) electrochemical sensor was prepared based on the specific recognition of 1, 2-naphthoquinone-4-sulphonic acid sodium salt (NQS) to CG for the first time. It was constructed with β-cyclodextrin-graphene oxide (β-CD-GO) on glassy carbon electrode (GCE) and modified with NQS to obtain NQS/β-CD-GO/GCE. A decrease of the oxidation peak current of NQS arising from the specific binding of CG and NQS through a nucleophilic substitution reaction was used for indirect detection of CG. The performances of the proposed sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The difference of the oxidation peak current was linear with the CG concentration in the range of 0.2-60.0 μM and the detection limit of CG was 0.061 μM. Moreover, the CG sensor showed good repeatability and high stability and has been applied to the determination of CG in human serum with satisfactory recoveries. So, a new method has been provided for detecting electrochemically inert material CG.

4 citations


Journal ArticleDOI
31 Mar 2018
TL;DR: In this article, a rapid, sensitive and simple optimized spectrophotometric method is developed for the determination of Glucosamine (GL) based on reaction of GL with sodium 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline medium forming orange colored product which measured at 451 nm.
Abstract: A rapid, sensitive and simple optimized spectrophotometric method is developed for the determination of Glucosamine (GL) based on reaction of GL with sodium 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline medium forming orange colored product which measured at 451 nm The method optimization was essential as many procedural parameters influenced the efficiency and reproducibility of the derivatization process including the reaction time, reaction temperature, NQS concentration, alkali concentration and solvents The objective of our study was to optimize and validate a spectrophotometric method using the reaction of GL with NQS for determining GL in dosage form The factors that may influence the efficiency and reproducibility of the derivatization process were identified and optimized The proposed method was validated and successfully applied for the analysis of GL in dosage form Statistical comparison of the results of the proposed method with the reference method showed excellent agreement and proved that no significant difference in the accuracy and precision The developed method is easy to use, accurate and least cost-effective for routine studies relative to HPLC and other techniques