885 research outputs found

    2-(Hy­droxy­meth­yl)pyridin-3-ol

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    In the crystal structure of the title compound, C6H7NO2, the mol­ecules are are linked by inter­molecular O—H⋯N and O—H⋯O hydrogen bonds; π–π stacking is observed between parallel pyridine rings of adjacent mol­ecules [centroid-to-centroid distance = 3.7649 (12) Å]

    rac-Methyl 2-(2-formyl-4-nitro­phen­oxy)hexa­noate

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    In the racemic title compound, C14H17NO6, the plane of the ester group of the methyl hexa­noate side chain makes a dihedral angle of 80.0 (2)° with the benzene ring, while the nitro group is approximately coplanar with the benzene ring [dihedral angle = 10.3 (2)°]. In the crystal, mol­ecules form weak aromatic C—H⋯Onitro hydrogen-bonding inter­actions, giving inversion dimers [graph set R 2 2(8)]

    5-Methyl-N-[2-(trifluoro­meth­yl)phen­yl]isoxazole-4-carboxamide

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    In the title compound, C12H9F3N2O2, the benzene ring is nearly perpendicular to the isoxazole ring, making a dihedral angle of 82.97 (2)°. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds into a supra­molecular chain running along the c axis

    Recent advances in the repair of degenerative intervertebral disc for preclinical applications

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    The intervertebral disc (IVD) is a load-bearing, avascular tissue that cushions pressure and increases flexibility in the spine. Under the influence of obesity, injury, and reduced nutrient supply, it develops pathological changes such as fibular annulus (AF) injury, disc herniation, and inflammation, eventually leading to intervertebral disc degeneration (IDD). Lower back pain (LBP) caused by IDD is a severe chronic disorder that severely affects patients’ quality of life and has a substantial socioeconomic impact. Patients may consider surgical treatment after conservative treatment has failed. However, the broken AF cannot be repaired after surgery, and the incidence of re-protrusion and reoccurring pain is high, possibly leading to a degeneration of the adjacent vertebrae. Therefore, effective treatment strategies must be explored to repair and prevent IDD. This paper systematically reviews recent advances in repairing IVD, describes its advantages and shortcomings, and explores the future direction of repair technology

    Quasi-Solid-State Ion-Conducting Arrays Composite Electrolytes with Fast Ion Transport Vertical-Aligned Interfaces for All-Weather Practical Lithium-Metal Batteries

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    The rapid improvement in the gel polymer electrolytes (GPEs) with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries. The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs. However, different ion transport capacity between solvent and polymer will cause local nonuniform Li+^+ distribution, leading to severe dendrite growth. In addition, the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes. Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs. Here, a strategy by introducing ion-conducting arrays (ICA) is created by vertical-aligned montmorillonite into GPE. Rapid ion transport on the ICA was demonstrated by 6^6Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction, combined with computer simulations to visualize the transport process. Compared with conventional randomly dispersed fillers, ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures. Therefore, GPE/ICA exhibits high room-temperature ionic conductivity (1.08 mS cm1^{−1}) and long-term stable Li deposition/stripping cycles (> 1000 h). As a final proof, Li||GPE/ICA||LiFePO4_4 cells exhibit excellent cycle performance at wide temperature range (from 0 to 60 °C), which shows a promising path toward all-weather practical solid-state batteries

    Approaching the standard quantum limit of a Rydberg-atom microwave electrometer

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    The development of a microwave electrometer with inherent uncertainty approaching its ultimate limit carries both fundamental and technological significance. Recently, the Rydberg electrometer has garnered considerable attention due to its exceptional sensitivity, small-size, and broad tunability. This specific quantum sensor utilizes low-entropy laser beams to detect disturbances in atomic internal states, thereby circumventing the intrinsic thermal noise encountered by its classical counterparts. However, due to the thermal motion of atoms, the advanced Rydberg-atom microwave electrometer falls considerably short of the standard quantum limit by over three orders of magnitude. In this study, we utilize an optically thin medium with approximately 5.2e5 laser-cooled atoms to implement heterodyne detection. By mitigating a variety of noises and strategically optimizing the parameters of the Rydberg electrometer, our study achieves an electric-field sensitivity of 10.0 nV/cm/Hz^1/2 at a 100 Hz repetition rate, reaching a factor of 2.6 above the standard quantum limit and a minimum detectable field of 540 pV/cm. We also provide an in-depth analysis of noise mechanisms and determine optimal parameters to bolster the performance of Rydberg-atom sensors. Our work provides insights into the inherent capacities and limitations of Rydberg electrometers, while offering superior sensitivity for detecting weak microwave signals in numerous applications.Comment: 12 page

    Functional building blocks for scalable multipartite entanglement in optical lattices

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    Featuring excellent coherence and operated parallelly, ultracold atoms in optical lattices form a competitive candidate for quantum computation. For this, a massive number of parallel entangled atom pairs have been realized in superlattices. However, the more formidable challenge is to scale-up and detect multipartite entanglement due to the lack of manipulations over local atomic spins in retro-reflected bichromatic superlattices. Here we developed a new architecture based on a cross-angle spin-dependent superlattice for implementing layers of quantum gates over moderately-separated atoms incorporated with a quantum gas microscope for single-atom manipulation. We created and verified functional building blocks for scalable multipartite entanglement by connecting Bell pairs to one-dimensional 10-atom chains and two-dimensional plaquettes of 2×42\times4 atoms. This offers a new platform towards scalable quantum computation and simulation
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