921 research outputs found

    Superfluid and magnetic states of an ultracold Bose gas with synthetic three-dimensional spin-orbit coupling in an optical lattice

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    We study ultracold bosonic atoms with the synthetic three-dimensional spin-orbit (SO) coupling in a cubic optical lattice. In the superfluidity phase, the lowest energy band exhibits one, two or four pairs of degenerate single-particle ground states depending on the SO-coupling strengths, which can give rise to the condensate states with spin-stripes for the weak atomic interactions. In the deep Mott-insulator regime, the effective spin Hamiltonian of the system combines three-dimensional Heisenberg exchange interactions, anisotropy interactions and Dzyaloshinskii-Moriya interactions. Based on Monte Carlo simulations, we numerically demonstrate that the resulting Hamiltonian with an additional Zeeman field has a rich phase diagram with spiral, stripe, vortex crystal, and especially Skyrmion crystal spin-textures in each xy-plane layer. The obtained Skyrmion crystals can be tunable with square and hexagonal symmetries in a columnar manner along the z axis, and moreover are stable against the inter-layer spin-spin interactions in a large parameter region.Comment: 9 pages, 4 figures; title modified, references and discussions added; accepted by PR

    Liquid Metal-Based Multifunctional Micropipette for 4D Single Cell Manipulation.

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    A novel manufacturing approach to fabricate liquid metal-based, multifunctional microcapillary pipettes able to provide electrodes with high electrical conductivity for high-frequency electrical stimulation and measurement is proposed. 4D single cell manipulation is realized by applying multifrequency, multiamplitude, and multiphase electrical signals to the microelectrodes near the pipette tip to create 3D dielectrophoretic trap and 1D electrorotation, simultaneously. Functions such as single cell trapping, patterning, transfer, and rotation are accomplished. Cell viability and multiday proliferation characterization has confirmed the biocompatibility of this approach. This is a simple, low-cost, and fast fabrication process that requires no cleanroom and photolithography step to manufacture 3D microelectrodes and microchannels for easy access to a wide user base for broad applications

    Progress in host–guest macrocycle/pesticide research: Recognition, detection, release and application

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    Macrocyclic compounds are formed via a series of cyclic oligomers possessing repeating units, and classical examples include cyclodextrins, calix[n]arenes, cucurbit[n]urils and pillar[n]arenes (n represents the number of repeat units). Given their unique host–guest binding ability, macrocycles are often developed as hosts for specific guest molecular assembly systems, adsorption materials, drug delivery carriers, catalysts, and molecular recognition systems. For example, macrocyclic host molecules are widely used to encapsulate hydrophobic drug molecules to improve both the solubility and utilization efficiency of the drug. One type of potential host molecule that has seen increased agricultural use in recent years are pesticides. This includes herbicides, insecticides, and fungicides, and given the increased use, there is need to develop systems that can rapidly and effectively identify and detect such pesticides. In this review, we will discuss the use of cucurbit[n]urils, pillar[n]arenes, calix[n]arenes, cyclodextrins in this area, and their ability to form host–guest species with herbicides, insecticides and fungicides. Particular emphasis is given to the ability of such systems to improve the toxicity and release of the pesticide and the potential for practical application

    Diagnostic value of multiple ultrasound diagnostic techniques for axillary lymph node metastases in breast cancer: A systematic analysis and network meta-analysis

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    BackgroundEarly diagnosis of axillary lymph node metastasis is very important for the recurrence and prognosis of breast cancer. Currently, Lymph node biopsy is one of the important methods to detect lymph node metastasis in breast cancer, however, its invasiveness might bring complications to patients. Therefore, this study investigated the diagnostic performance of multiple ultrasound diagnostic methods for axillary lymph node metastasis of breast cancer.Materials and methodsIn this study, we searched PubMed, Web of Science, CNKI and Wan Fang databases, conducted Bayesian network meta-analysis (NMA) on the studies that met the inclusion criteria, and evaluated the consistency of five different ultrasound imaging techniques in axillary lymph node metastasis of breast cancer. Funnel graph was used to evaluate whether it had publication bias. The diagnostic performance of each ultrasound imaging method was ranked using SUCRAResultsA total of 22 papers were included, US+CEUS showed the highest SUCRA values in terms of sensitivity (SEN) (0.874), specificity (SPE) (0.911), positive predictive value (PPV) (0.972), negative predictive value (NPV) (0.872) and accuracy (ACC) (0.990).ConclusionIn axillary lymph node metastasis of breast cancer, the US+CEUS combined diagnostic method showed the highest SUCRA value among the five ultrasound diagnostic methods. This study provides a theoretical basis for preoperative noninvasive evaluation of axillary lymph node metastases in breast cancer patients and clinical treatment decisions.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022351977

    A cucurbit[8]uril-based fluorescent probe for the selective detection of pymetrozine

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    Herein, we report a simple fluorescence-enhanced system for the selective recognition and determination of the insecticide pymetrozine. 1H NMR spectroscopic data indicate that 1,2-bis(4-pyridyl)ethylene (BPE) is partially encapsulated in the cavity of the cucurbit[8]uril (Q[8]) in aqueous solution, forming a stable 1:2 host-guest inclusion complex. Good evidence is also provided by other characterization techniques including single crystal X-ray diffraction, UV-Vis and fluorescence spectroscopies. This host-guest inclusion complex shows weak fluorescence in aqueous solution. Interestingly, the addition of pymetrozine greatly enhanced the fluorescence of the host-guest inclusion complex. In contrast, no significant fluorescence enhancement was observed on addition of 10 other pesticides. The concentration of pymetrozine in aqueous solution was easily detected based on the linear relationship between fluorescence intensity and pymetrozine concentration. Therefore, this paper reports a new method to identify and determine pymetrozine by fluorescence enhancement

    A fluorescent probe based on cucurbit[7]uril for the selective recognition of phenylalanine

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    © 2020 Elsevier B.V. Herein we describe a simple fluorescence quenching method for the selective recognition and determination of the amino acid phenylalanine (Phe). The use of 1H NMR spectroscopy revealed that the alkaloid palmatine (PAL) can encapsulated partially into the cavity of cucurbit[7]uril (Q[7]) in aqueous solution to form a stable 1:1 host−guest inclusion complex. This host-guest complex exhibits fluorescence of moderate intensity. Interestingly, the addition of the Phe results in a dramatic quenching of the fluorescence intensity associated with the inclusion complex. By contrast, the addition of other natural amino acids resulted in no change in the fluorescence. Based on the linear relationship between the fluorescence intensity and the concentration of Phe, the detection of the concentration of Phe in aqueous solution is facile. Thus, a new fluorescence quenching method for the recognition and determination of the Phe has established herein

    A study of the inclusion complex formed between cucurbit[8]uril and isonicotinic acid

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    The complexation between cucurbit[8]uril, Q[8], and isonicotinic acid has been studied using 1H NMR spectroscopy, UV–Vis absorption spectroscopy, Raman spectroscopy and single crystal X-ray diffraction. The results revealed that the 2:1 inclusion complex (4-PA)2@Q[8]·25H2O is formed, with two guests simultaneously encapsulated in the hydrophobic cavity; the mean planes of the guests are 3.535 Å apart. Graphical abstract: [Figure not available: see fulltext.

    A controllable superconducting electromechanical oscillator with a suspended membrane

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    We fabricate a microscale electromechanical system, in which a suspended superconducting membrane, treated as a mechanical oscillator, capacitively couples to a superconducting microwave resonator. As the microwave driving power increases, nonmonotonic dependence of the resonance frequency of the mechanical oscillator on the driving power has been observed. We also demonstrate the optical switching of the resonance frequency of the mechanical oscillator. Theoretical models for qualitative understanding of our experimental observations are presented. Our experiment may pave the way for the application of a mechanical oscillator with its resonance frequency controlled by the electromagnetic and/or optical fields, such as a microwave-optical interface and a controllable element in a superqubit-mechanical oscillator hybrid system.Comment: 8 pages,4 figure

    Association between short-term exposure to ambient air pollution and heart failure: An updated systematic review and meta-analysis of more than 7 million participants

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    IntroductionExposure to air pollution has been linked to the mortality of heart failure. In this study, we sought to update the existing systematic review and meta-analysis, published in 2013, to further assess the association between air pollution and acute decompensated heart failure, including hospitalization and heart failure mortality.MethodsPubMed, Web of Science, EMBASE, and OVID databases were systematically searched till April 2022. We enrolled the studies regarding air pollution exposure and heart failure and extracted the original data to combine and obtain an overall risk estimate for each pollutant.ResultsWe analyzed 51 studies and 7,555,442 patients. Our results indicated that heart failure hospitalization or death was associated with increases in carbon monoxide (3.46% per 1 part per million; 95% CI 1.0233–1.046, P < 0.001), sulfur dioxide (2.20% per 10 parts per billion; 95% CI 1.0106–1.0335, P < 0.001), nitrogen dioxide (2.07% per 10 parts per billion; 95% CI 1.0106–1.0335, P < 0.001), and ozone (0.95% per 10 parts per billion; 95% CI 1.0024–1.0166, P < 0.001) concentrations. Increases in particulate matter concentration were related to heart failure hospitalization or death (PM2.5 1.29% per 10 μg/m3, 95% CI 1.0093–1.0165, P < 0.001; PM10 1.30% per 10 μg/m3, 95% CI 1.0102–1.0157, P < 0.001).ConclusionThe increase in the concentration of all pollutants, including gases (carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone) and particulate matter [(PM2.5), (PM10)], is positively correlated with hospitalization rates and mortality of heart failure.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021256241
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