History of the tether concept and tether missions: a review

This paper introduces history of space tethers, including tether concepts and tether missions, and attempts to provide a source of references for historical understanding of space tethers. Several concepts of space tethers since the original concept has been conceived are listed in the literature, as well as a summary of interesting applications, and a research of space tethers is given. With the aim of implementing scientific experiments in aerospace, several space tether missions which have been delivered for aerospace application are introduced in the literature.</jats:p

4-Benzyl-4-ethyl­morpholin-1-ium hexa­fluoro­phosphate

The asymmetric unit of the title compound, C13H20NO+·PF6 −, contains two cations, one complete anion and two half hexa­fluoro­phosphate anions having crystallographically imposed twofold rotation symmetry. In the cations, the morpholine rings are in a chair conformation. In the crystal, ions are linked by weak C—H⋯F hydrogen bonds into a three-dimensional network

Mitochondria-Targeted Antioxidant Prevents Cardiac Dysfunction Induced by Tafazzin Gene Knockdown in Cardiac Myocytes

Tafazzin, a mitochondrial acyltransferase, plays an important role in cardiolipin side chain remodeling. Previous studies have shown that dysfunction of tafazzin reduces cardiolipin content, impairs mitochondrial function, and causes dilated cardiomyopathy in Barth syndrome. Reactive oxygen species (ROS) have been implicated in the development of cardiomyopathy and are also the obligated byproducts of mitochondria. We hypothesized that tafazzin knockdown increases ROS production from mitochondria, and a mitochondria-targeted antioxidant prevents tafazzin knockdown induced mitochondrial and cardiac dysfunction. We employed cardiac myocytes transduced with an adenovirus containing tafazzin shRNA as a model to investigate the effects of the mitochondrial antioxidant, mito-Tempo. Knocking down tafazzin decreased steady state levels of cardiolipin and increased mitochondrial ROS. Treatment of cardiac myocytes with mito-Tempo normalized tafazzin knockdown enhanced mitochondrial ROS production and cellular ATP decline. Mito-Tempo also significantly abrogated tafazzin knockdown induced cardiac hypertrophy, contractile dysfunction, and cell death. We conclude that mitochondria-targeted antioxidant prevents cardiac dysfunction induced by tafazzin gene knockdown in cardiac myocytes and suggest mito-Tempo as a potential therapeutic for Barth syndrome and other dilated cardiomyopathies resulting from mitochondrial oxidative stress

Pressure driven depolarization behavior of Bi 0.5 Na 0.5 TiO 3 based lead-free ceramics

Pressure driven depolarization behavior has been widely investigated for its scientific significance and practical applications. However, previous related studies were all based on lead-containing ferroelectric (FE) materials leading to detrimental environmental concerns. In the present work, we report the pressure driven depolarization behavior in Bi-based lead-free 0.97[(1-x)Bi0.5Na0.5TiO3-xBiAlO3)]-0.03K0.5Na0.5NbO3 (BNT-x) ceramics. Particularly, with increasing hydrostatic pressure from 0 MPa to 495 MPa, the remanent polarization of BNT-0.04 decreases from 30.7 µC/cm2 to 8.2 µC/cm2, reducing &$8764;73% of its initial value. The observed depolarization phenomenon is associated with the pressure induced polar FE-nonpolar relaxor phase transition. The results reveal BNT based ceramics as promising lead free candidates for mechanical-electrical energy conversion applications based on the pressure driven depolarization behavior.This work was supported by Chinese Academy of Sciences Research Equipment Development Project (No. YZ201332), National Program on Key Basic Research Project (973 Program) (No. 2012CB619406), Shanghai International Science and Technology Cooperation Project (No. 13520700700), and international partnership project of Chinese Academy of Science. Zhen Liu also acknowledges the support of Shanghai Sailing Program (No. 17YF1429700)

High performance Bi₀.₅Na₀.₅TiO₃-BiAlO₃-K₀.₅Na₀.₅NbO₃ lead-free pyroelectric ceramics for thermal detectors

Both high pyroelectric properties and good temperature stability of ferroelectric materials are desirable when used for applications in infrared thermal detectors. In this work, we report lead-free ternary 0.97(0.99Bi0.5Na0.5TiO3-0.01BiAlO3)-0.03K0.5Na0.5NbO3 (BNT-BA-KNN) ceramics, which not only exhibits a large pyroelectric coefficient (p ∼ 3.7 × 10-8 C cm-2K-1) and figures of merit (Fi, Fv, and Fd) but also shows excellent thermal stable properties. At room temperature, Fi, Fv, and Fd are determined as high as 1.32 × 10-10 m/V, 2.89 × 10-2 m2/C, and 1.15 × 10-5Pa-1/2 at 1 kHz and 1.32 × 10-10 m/V, 2.70 × 10-2 m2/C, and 1.09 × 10-5Pa-1/2 at 20 Hz, respectively. During the temperature range of RT to 85 °C, the achieved p, Fi, Fv, and Fd do not vary too much. The high depolarization temperature and the undispersed ferroelectric-ergodic relaxor phase transition with a sharp pyroelectric coefficient peak value of ∼400 × 10-8 C cm-2K-1 are suggested to be responsible for this thermal stability, which ensures reliable actual operation. The results reveal the BNT-BA-KNN ceramics as promising lead-free candidates for infrared thermal detector applications.This work was supported by the Chinese Academy of Sciences Research Equipment Development Project (No. YZ201332), the National Natural Science Foundation (NSFC) of China (No. 61475176), the Shanghai International Science and Technology Cooperation Project (Grant No. 13520700700), and the International Partnership Project of Chinese Academy of Science. Zhen Liu also acknowledges the support of the Shanghai Sailing Program (No. 17YF1429700)

Controlling the non-linear emission of upconversion nanoparticles to enhance super-resolution imaging performance

Upconversion nanoparticles (UCNPs) exhibit unique optical properties such as photo-emission stability, large anti-Stokes shift, and long excited-state lifetimes, allowing significant advances in a broad range of applications from biomedical sensing to super-resolution microscopy. In recent years, progress on nanoparticle synthesis led to the development of many strategies for enhancing their upconversion luminescence, focused in particular on heavy doping of lanthanide ions and core–shell structures. In this article, we investigate the non-linear emission properties of fully Yb-based core–shell UCNPs and their impact on the super-resolution performance of stimulated excitation-depletion (STED) microscopy and super-linear excitation-emission (uSEE) microscopy. Controlling the power-dependent emission curve enables us to relax constraints on the doping concentrations and to reduce the excitation power required for accessing sub-diffraction regimes. We take advantage of this feature to implement multiplexed super-resolution imaging of a two-sample mixture

High-precision pinpointing of luminescent targets in encoder assisted scanning microscopy allowing high-speed quantitative analysis

Compared with routine microscopy imaging of a few analytes at a time, rapid scanning through the whole sample area of a microscope slide to locate every single target object offers many advantages in terms of simplicity, speed, throughput, and potential for robust quantitative analysis. Existing techniques that accommodate solid-phase samples incorporating individual micrometer-sized targets generally rely on digital microscopy and image analysis, with intrinsically low throughput and reliability. Here, we report an advanced on-the-fly stage scanning method to achieve high-precision target location across the whole slide. By integrating X- and Y-axis linear encoders to a motorized stage as the virtual "grids" that provide real-time positional references, we demonstrate an orthogonal scanning automated microscopy (OSAM) technique which can search a coverslip area of 50 X 24 mm² in just 5.3 min and locate individual 15 μm lanthanide luminescent microspheres with standard deviations of 1.38 and 1.75 μm in X and Y directions. Alongside implementation of an autofocus unit that compensates the tilt of a slide in the Z-axis in real time, we increase the luminescence detection efficiency by 35% with an improved coefficient of variation. We demonstrate the capability of advanced OSAM for robust quantification of luminescence intensities and lifetimes for a variety of micrometer-scale luminescent targets, specifically single down-shifting and upconversion microspheres, crystalline microplates, and color-barcoded microrods, as well as quantitative suspension array assays of biotinylated-DNA functionalized upconversion nanoparticles.8 page(s