Gaia Data Release 2 Katz, D.; Sartoretti, P.; Cropper, M. ...
Astronomy and astrophysics (Berlin),
02/2019, Volume:
622
Journal Article, Web Resource
Peer reviewed
Open access
Context.
For
Gaia
DR2, 280 million spectra collected by the Radial Velocity Spectrometer instrument on board
Gaia
were processed, and median radial velocities were derived for 9.8 million sources ...brighter than
G
RVS
= 12 mag.
Aims.
This paper describes the validation and properties of the median radial velocities published in
Gaia
DR2.
Methods.
Quality tests and filters were applied to select those of the 9.8 million radial velocities that have the quality to be published in
Gaia
DR2. The accuracy of the selected sample was assessed with respect to ground-based catalogues. Its precision was estimated using both ground-based catalogues and the distribution of the
Gaia
radial velocity uncertainties.
Results. Gaia
DR2 contains median radial velocities for 7 224 631 stars, with
T
eff
in the range 3550, 6900 K, which successfully passed the quality tests. The published median radial velocities provide a full-sky coverage and are complete with respect to the astrometric data to within 77.2% (for
G
≤ 12.5 mag). The median radial velocity residuals with respect to the ground-based surveys vary from one catalogue to another, but do not exceed a few 100 m s
−1
. In addition, the
Gaia
radial velocities show a positive trend as a function of magnitude, which starts around
G
RVS
~ 9 mag and reaches about + 500 m s
−1
at
G
RVS
= 11.75 mag. The origin of the trend is under investigation, with the aim to correct for it in
Gaia
DR3. The overall precision, estimated from the median of the
Gaia
radial velocity uncertainties, is 1.05 km s
−1
. The radial velocity precision is a function of many parameters, in particular, the magnitude and effective temperature. For bright stars,
G
RVS
∈ 4, 8 mag, the precision, estimated using the full dataset, is in the range 220–350 m s
−1
, which is about three to five times more precise than the pre-launch specification of 1 km s
−1
. At the faint end,
G
RVS
= 11.75 mag, the precisions for
T
eff
= 5000 and 6500 K are 1.4 and 3.7 km s
−1
, respectively.
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UNRAVELING THE MYSTERY OF EXOSOMES Wang, H.; Lee, C.; Huang, M.
Cytotherapy (Oxford, England),
June 2024, 2024-06-00, Volume:
26, Issue:
6
Journal Article
Peer reviewed
Exosomes are secreted by cells as carriers of lipids, functional proteins, mRNAs, miRNAs, lncRNAs and DNA, playing an essential role in intercellular communication. In recent years, exosomes from ...platelet lysate have shown their ability to promote tissue repair and regeneration given their abundance of growth factors and cytokines. In addition, they have attracted attention for their role in blood coagulation, immunomodulation, and vascular biology. However, the lack of standardized isolation and analysis methods for exosomes has limited their clinical applications. This study aimed to analyze the contents of human platelet lysate exosomes, explore the correlation with their biological functions, and evaluate their differences in composition, with an overarching goal to understand the potential regulatory mechanisms.
To explore the contents of human platelet lysate exosomes (HPLP-EVs), we used platelet lysate, instead of fetal bovine serum (FBS), and Tangential Flow Filtration (TFF) to concentrate and purify the HPLP-EVs to separate the exosomes by size particle. Next, we tried four different ways to break the purified HPLP-EVs: freeze-thaw reaction, ultrasound, magnetic bead beating homogenization, and double distilled water osmotic pressure equilibrium. We confirmed which method was optimal for extracting the internal components of exosomes, and further analyzed the compositional differences of the contents of HPLP-EVs by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF), UPLC-MS/MS, and Nucleic Acid Sequence Analysis. We also performed the systematic identification of proteins and nucleic acids in exosomes of different sizes. Ultimately, by analyzing the composition and activity efficacy of HPLP-EVs of different sizes, the correlation between HPLP-EVs and nucleic acids will be analyzed to provide a new guideline for future research.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
This paper is concerned with the history, properties, development, application, and prospects of soft X-ray (2 – 300 Å) VLS spectrometers, i.e., spectrometers with reflection diffraction ...gratings whose spacing varies monotonically across the aperture according to a prescribed law (so-called Varied Line-Space (VLS) gratings). An important feature of grazing-incidence VLS spectrometers is that the spectrum is formed on a nearly flat surface perpendicular (or slightly inclined) to the diffracted beams, making them perfectly compatible with modern CCD detectors. VLS spectrometers are employed for the spectroscopy of laboratory and astrophysical plasmas, including the diagnostics of relativistic laser-produced plasmas, for measuring the linewidth of an X-ray laser, for recording the high-order harmonics of laser radiation, and for recording the emission of fast electric discharges and other laboratory X-ray sources. Instruments with VLS gratings are employed to advantage in reflectometry/metrology, X-ray fluorescence analysis, and microscopy with the use of synchrotron, free-electron laser, and laser-produced plasma radiation, as well as in SXR emission spectroscopy, combined with an electron microscope (SXES). Recent years have seen the active development of VLS spectrometers dedicated to the investigation of the electronic structure of different materials and molecules by resonant inelastic X-ray scattering (RIXS) spectroscopy with synchrotron radiation. Among recent trends is the development of VLS gratings with a multilayer reflective coating and extension of the operating spectral range towards ‘tender’ X-rays (
ℏω
∼ 1.5 – 6 keV), some projects aiming to achieve a resolving power
λ
/
δ λ
∼ 10
5
in the region
ℏω
∼ 1 keV.
Three spatial heterodyne Raman spectrometers, one free standing, the others monolithic, have been used for remote Raman and LIBS for samples at a distance of 4.5 m and 1D Raman imaging. The wide area ...measurement capability of the SHS was demonstrated and shown to reduce sample photodegradation in the case of Raman, using large laser spots on the sample, without loss of signal or decreased spectral resolution. 1D Raman imaging using a free standing SHRS and a monolithic SHRS was demonstrated and shown to provide better signal-to-noise ratio (SNR) spectra for heterogenous samples than spectra measured without imaging. Improved SNR using 1D imaging is the result of spatial separation of the signal from different areas of the sample, which reduces the contribution of shot noise from stronger scattering sample regions to more weakly scattering adjacent sample regions. For 1D imaging of adjacent samples, within the field-of-view (FOV) of the spectrometer, the SNR improved up to four times, with no loss of spectral resolution or spectral range, and a spatial resolution of 280 μm was demonstrated for samples located at 4.5 m from the spectrometer.
•Benchtop and monolithic spatial heterodyne Raman spectrometers were used for remote Raman and LIBS at 4.5 m.•For Raman, a large field of view allowed reduced sample photodegradation with no loss of signal or spectral resolution.•1D SHRS Raman imaging provides higher signal-to-noise ratio for heterogenous samples than spectra measured without imaging.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
15.
Conceptual design of the AGATA 1π array at GANIL Clément, E.; Michelagnoli, C.; de France, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2017, Volume:
855
Journal Article
Peer reviewed
Open access
The Advanced GAmma Tracking Array (AGATA) has been installed at the GANIL facility, Caen-France. This set-up exploits the stable and radioactive heavy-ions beams delivered by the cyclotron ...accelerator complex of GANIL. Additionally, it benefits from a large palette of ancillary detectors and spectrometers to address in-beam γ-ray spectroscopy of exotic nuclei. The set-up has been designed to couple AGATA with a magnetic spectrometer, charged-particle and neutron detectors, scintillators for the detection of high-energy γ rays and other devices such as a plunger to measure nuclear lifetimes. In this paper, the design and the mechanical characteristics of the set-up are described. Based on simulations, expected performances of the AGATA 1π array are presented.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Tree diseases endanger forestry and fruit tree plantations seriously worldwide in the past decades, leading to significant economic losses for the agricultural production sector. Rapid and accurate ...detection of tree diseases is crucial in tree protection. Despite molecular biological detection methods have prominent specificity, they are time-consuming and laborious, and are not suitable for large-scale detection of tree diseases. Spectroscopy with nondestructive, rapid, and high throughput characteristics has been applied to plant disease detection. Spectral detection systems are divided into three categories according to the spectrometer's carrying platform: portable hand-held spectrometer, airborne vehicle-mounted spectrometer, and large laboratory spectrometer. This review summarized three main spectral detection systems and their advantages and disadvantages in detecting various diseases of forestry and fruit trees: including detection of the single disease, multiple stress, and early disease using Visible/near-infrared, Raman, and hyperspectral imaging. Finally, spectroscopy detection technology applications of challenges were summarized, highlighting future trends.
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A monolithic spatial heterodyne Raman spectrometer (mSHRS) is described, where the optical components of the spectrometer are bonded to make a small, stable, one-piece structure. This builds on ...previous work, where we described bench top spatial heterodyne Raman spectrometers (SHRS), developed for planetary spacecraft and rovers. The SHRS is based on a fixed grating spatial heterodyne spectrometer (SHS) that offers high spectral resolution and high light throughput in a small footprint. The resolution of the SHS is not dependent on a slit, and high resolution can be realized without using long focal length dispersing optics since it is not a dispersive device. Thus, the SHS can be used as a component in a compact Raman spectrometer with high spectral resolution and a large spectral range using a standard 1024 element charge-coupled device. Since the resolution of the SHRS is not dependent on a long optical path, it is amenable to the use of monolithic construction techniques to make a compact and robust device. In this paper, we describe the use of two different monolithic SHSs (mSHSs), with Littrow wavelengths of 531.6 nm and 541.05 nm, each about 3.5 × 3.5 × 2.5 cm in size and weighing about 80 g, in a Raman spectrometer that provides ∼3500 cm−1 spectral range with 4–5 cm−1 and 8–9 cm−1 resolution, for 600 grooves/mm and 150 grooves/mm grating-based mSHS devices, respectively. In this proof of concept paper, the stability, spectral resolution, spectral range, and signal-to-noise ratio of the mSHRS spectrometers are compared to our bench top SHRS that uses free-standing optics, and signal to noise comparisons are also made to a Kaiser Holospec f/1.8 Raman spectrometer.
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A modern cold triple-axis spectrometer to study quantum condensed matter systems is planned for the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Here, we describe the conceptual ...principles and design of a secondary spectrometer using a multiplexed, prismatic analyzer system relying on graphite crystals and inspired by the successful implementation of the Continuous Angle Multiple Energy Analysis (CAMEA) spectrometers at the Paul Scherrer Institute. This project is currently known as MANTA for Multi-Analyzer Neutron Triple-Axis. We report Monte-Carlo ray-tracing simulations on a simple but realistic sample scattering kernel to further illustrate the prismatic analyzer concept’s workings, calibration, and performance. Then, we introduce a new statistical analysis approach based on the prismatic analyzer concept to improve the number of final energies measured on the spectrometer. We also study possible evolutions in the CAMEA design relevant for MANTA.
•Monte Carlo simulations of a new spectrometer at the High Flux Isotope Reactor.•Development of the Positionally Calibrated Prismatic Analysis technique.•New multiplexed, prismatic analyzer-based designs explored.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Miniaturized optical spectrometers have been realized by exploiting conventional working principles and advanced nanofabrication technology. Especially in the mid-infrared (MIR) range, chip-scale ...optical spectrometers enable fast and on-site detection of molecular fingerprints for selective chemical sensing in healthcare and environmental monitoring. This miniaturization is also highly desirable for the wearable devices where the tiny functional parts remain on rigid substrates but the electronics are flexible. In the last decade, the triboelectric nanogenerator (TENG) technology has been proven as an indispensable and enabling technology for wearable self-powered sensors, energy harvesters and voltage sources, etc. Although a few TENG based gas sensors have been demonstrated, each of these sensors can detect a particular gas other than diversified gases. Infrared spectrometer is known as an instrument which can investigate the infrared absorption characteristics of gas molecules. It is the best generic technology to sense multiple gases on the same instrument, or device. In this study, we demonstrate a TENG enabled tunable Fabry-Pérot (FP) photonic-crystal-slab filter aiming for the computational spectrometer in the MIR range. The textile-triboelectric nanogenerator (T-TENG) provides high open-circuit voltage to shift the resonance wavelengths of the electrostatically actuated FP-filter, where this feature provides the sampling bases required for the computational spectrometer. Furthermore, the FP-filter is fabricated by a new transfer-printing method and shows a large wavelength tunability. As a proof of concept, the transmission spectrum of acetone vapor is reconstructed from 5 to 6.5 µm using this TENG enabled FP-filter. The molecular fingerprint of acetone is identified at 5.75 µm. This work paves the way towards the wearable MIR miniaturized optical spectrometer.
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•A MEMS tunable Fabry-Perot (FP) photonic-crystal-slab filter is fabricated by transfer-printing method.•The computational optical spectrometer is demonstrated for the first time with a single MEMS tunable device.•A textile-TENG is incorporated to tune the resonance of FP filter, forming the sampling bases for computational spectrometer.•The transmission spectra of CO2 and acetone are reconstructed with their molecular fingerprints identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mass spectrometry (MS) is an information rich analytical technique and plays a key role in various ‘omics studies. Standard mass spectrometers are bulky and operate at high vacuum, which hinder their ...adoption by the broader community and utility in field applications. Developing portable mass spectrometers can significantly expand the application scope and user groups of MS analysis. This review discusses the basics and recent advancements in the development of key components of portable mass spectrometers including ionization source, mass analyzer, detector, and vacuum system. Further, major areas where portable mass spectrometers are applied are also discussed. Finally, a perspective on the further development of portable mass spectrometers including the potential benefits for ‘omics analysis is provided.
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