Hybrid semiconductor-superconductor nanowires have emerged as a promising platform for realizing topological superconductivity (TSC). Here, we present a route to TSC using magnetic flux applied to a ...full superconducting shell surrounding a semiconducting nanowire core. Tunneling into the core reveals a hard induced gap near zero applied flux, corresponding to zero phase winding, and a gapped region with a discrete zero-energy state around one applied flux quantum, corresponding to 2π phase winding. Theoretical analysis indicates that the winding of the superconducting phase can induce a transition to a topological phase supporting Majorana zero modes. Measured Coulomb blockade peak spacing around one flux quantum shows a length dependence that is consistent with the existence of Majorana modes at the ends of the nanowire.
We introduce selective area grown hybrid InAs/Al nanowires based on molecular beam epitaxy, allowing arbitrary semiconductor-superconductor networks containing loops and branches. Transport reveals a ...hard induced gap and unpoisoned 2e-periodic Coulomb blockade, with temperature dependent 1e features in agreement with theory. Coulomb peak spacing in parallel magnetic field displays overshoot, indicating an oscillating discrete near-zero subgap state consistent with device length. Finally, we investigate a loop network, finding strong spin-orbit coupling and a coherence length of several microns. These results demonstrate the potential of this platform for scalable topological networks among other applications.
Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, and control of Majorana bound states (MBSs). We demonstrate the emergence of MBSs ...from coalescing Andreev bound states (ABSs) in a hybrid InAs nanowire with epitaxial Al, using a quantum dot at the end of the nanowire as a spectrometer. Electrostatic gating tuned the nanowire density to a regime of one or a few ABSs. In an applied axial magnetic field, a topological phase emerges in which ABSs move to zero energy and remain there, forming MBSs. We observed hybridization of the MBS with the end-dot bound state, which is in agreement with a numerical model. The ABS/MBS spectra provide parameters that are useful for understanding topological superconductivity in this system.
We use the effective g factor of Andreev subgap states in an axial magnetic field to investigate how the superconducting density of states is distributed between the semiconductor core and the ...superconducting shell in hybrid nanowires. We find a steplike reduction of the Andreev g factor and an improved hard gap with reduced carrier density in the nanowire, controlled by gate voltage. These observations are relevant for Majorana devices, which require tunable carrier density and a g factor exceeding that of the parent superconductor.
We report an experiment to test quantum interference, entanglement, and nonlocality using two dissimilar photon sources, the Sun and a semiconductor quantum dot on the Earth, which are separated by ...∼150 million kilometers. By making the otherwise vastly distinct photons indistinguishable in all degrees of freedom, we observe time-resolved two-photon quantum interference with a raw visibility of 0.796(17), well above the 0.5 classical limit, providing unambiguous evidence of the quantum nature of thermal light. Further, using the photons with no common history, we demonstrate postselected two-photon entanglement with a state fidelity of 0.826(24) and a violation of Bell inequality by 2.20(6). The experiment can be further extended to a larger scale using photons from distant stars and open a new route to quantum optics experiments at an astronomical scale.
Rejection diagnosis by endomyocardial biopsy (EMB) is invasive, expensive and variable. We investigated gene expression profiling of peripheral blood mononuclear cells (PBMC) to discriminate ISHLT ...grade 0 rejection (quiescence) from moderate/severe rejection (ISHLT ≥3A). Patients were followed prospectively with blood sampling at post‐transplant visits. Biopsies were graded by ISHLT criteria locally and by three independent pathologists blinded to clinical data. Known alloimmune pathways and leukocyte microarrays identified 252 candidate genes for which real‐time PCR assays were developed. An 11 gene real‐time PCR test was derived from a training set (n = 145 samples, 107 patients) using linear discriminant analysis (LDA), converted into a score (0–40), and validated prospectively in an independent set (n = 63 samples, 63 patients). The test distinguished biopsy‐defined moderate/severe rejection from quiescence (p = 0.0018) in the validation set, and had agreement of 84% (95% CI 66% C94%) with grade ISHLT ≥3A rejection. Patients >1 year post‐transplant with scores below 30 (approximately 68% of the study population) are very unlikely to have grade ≥3A rejection (NPV = 99.6%). Gene expression testing can detect absence of moderate/severe rejection, thus avoiding biopsy in certain clinical settings. Additional clinical experience is needed to establish the role of molecular testing for clinical event prediction and immunosuppression management.
Aims
To purify and characterize the biosurfactants produced by Achromobacter sp. HZ01.
Methods and Results
After fermentation, one biosurfactant was successfully purified from the fermentation broth ...of strain HZ01 by centrifugation, extraction using ethyl acetate, silica gel chromatography and reversed phase–high performance liquid chromatography. The critical micelle concentration (CMC) of the biosurfactant and the effects of temperatures, pH and salinities on its stability were determined. Fourier transform infrared spectroscopy, analysis of fatty acids and amino acids and mass spectrometry were used to characterize the biosurfactant. The maximum production yield of the crude biosurfactant reached to 6·84 g l−1 after incubation for 96 h. Except the favourable adaptability to a wide range of temperatures, pH and salinities, the biosurfactant with a CMC value of 48 mg l−1 could efficiently emulsify diverse hydrophobic compounds. The chemical formula of this biosurfactant was confirmed to be CH3‐(CH2)17‐CHO‐CH2‐CO‐Gly‐Gly‐Leu‐Met‐Leu‐Leu, in which the oxygen atom of group CHO linked to the last amino acid (Leu), a structure had never been reported before.
Conclusions
The purified biosurfactant is a novel cyclic lipopeptide.
Significance and Impact of the Study
One novel lipopeptide was purified and characterized. The novel biosurfactant exhibited good potential applications, such as bioremediation.
In this study, a new self-healing shape memory polymer (SMP) coating was prepared to protect the aluminum alloy 2024-T3 from corrosion by the incorporation of dual-function microspheres containing ...polycaprolactone and the corrosion inhibitor 8-hydroxyquinoline (8HQ). The self-healing properties of the coatings were investigated via scanning electron microscopy, electrochemical impedance spectroscopy, and scanning electrochemical microscopy following the application of different healing conditions. The results demonstrated that the coating possessed a triple-action self-healing ability enabled by the cooperation of the 8HQ inhibitor, the SMP coating matrix, and the melted microspheres. The coating released 8HQ in a pH-dependent fashion and immediately suppressed corrosion within the coating scratch. After heat treatment, the scratched coating exhibited excellent recovery of its anticorrosion performance, which was attributed to the simultaneous initiation of scratch closure by the shape memory effect of the coating matrix, sealing of the scratch by the melted microspheres, and the synergistic effect of corrosion inhibition by 8HQ.
We discuss the phenomenon of enhanced fluorescence in the proximity of metal nanostructures addressing the question of how much fluorescence signal can be obtained from fluorophores in such altered ...environments. We review its applicability for the methodologies used in the life science, such as immunoassays, flow cytometry and bioimaging. Experimental and theoretical scenarios employing various metal nanostructures - such as homogeneous enhancing substrates, fluorescence-enhancing microbeads, and metal core-dielectric shell nanocomposites - are described.
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