| 1. |
- Sugita, S., et al.
(författare)
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The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes
- 2019
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Ingår i: Science. - : AAAS. - 0036-8075 .- 1095-9203. ; 364:6437
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Tidskriftsartikel (refereegranskat)abstract
- Asteroids fall to Earth in the form of meteorites, but these provide little information about their origins. The Japanese mission Hayabusa2 is designed to collect samples directly from the surface of an asteroid and return them to Earth for laboratory analysis. Three papers in this issue describe the Hayabusa2 team's study of the near-Earth carbonaceous asteroid 162173 Ryugu, at which the spacecraft arrived in June 2018 (see the Perspective by Wurm). Watanabeet al.measured the asteroid's mass, shape, and density, showing that it is a “rubble pile” of loose rocks, formed into a spinning-top shape during a prior period of rapid spin. They also identified suitable landing sites for sample collection. Kitazatoet al.used near-infrared spectroscopy to find ubiquitous hydrated minerals on the surface and compared Ryugu with known types of carbonaceous meteorite. Sugitaet al.describe Ryugu's geological features and surface colors and combined results from all three papers to constrain the asteroid's formation process. Ryugu probably formed by reaccumulation of rubble ejected by impact from a larger asteroid. These results provide necessary context to understand the samples collected by Hayabusa2, which are expected to arrive on Earth in December 2020.Science, this issue p.268, p.272, p.eaaw0422; see also p.230
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| 2. |
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
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| 5. |
- Dahmen, J., et al.
(författare)
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Osteochondral Lesions of the Tibial Plafond and Ankle Instability With Ankle Cartilage Lesions: Proceedings of the International Consensus Meeting on Cartilage Repair of the Ankle
- 2022
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Ingår i: Foot & Ankle International. - : SAGE Publications. - 1071-1007 .- 1944-7876. ; 43:3, s. 448-452
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Tidskriftsartikel (refereegranskat)abstract
- Background: An international consensus group of experts was convened to collaboratively advance toward consensus opinions based on the best available evidence on key topics within cartilage repair of the ankle. The purpose of this article is to present the consensus statements on osteochondral lesions of the tibial plafond (OLTP) and on ankle instability with ankle cartilage lesions developed at the 2019 International Consensus Meeting on Cartilage Repair of the Ankle. Methods: Forty-three experts in cartilage repair of the ankle were convened and participated in a process based on the Delphi method of achieving consensus. Questions and statements were drafted within 4 working groups focusing on specific topics within cartilage repair of the ankle, after which a comprehensive literature review was performed and the available evidence for each statement was graded. Discussion and debate occurred in cases where statements were not agreed on in unanimous fashion within the working groups. A final vote was then held. Results: A total of 11 statements on OLTP reached consensus. Four achieved unanimous support and 7 reached strong consensus (greater than 75% agreement). A total of 8 statements on ankle instability with ankle cartilage lesions reached consensus during the 2019 International Consensus Meeting on Cartilage Repair of the Ankle. One achieved unanimous support, and seven reached strong consensus (greater than 75% agreement). Conclusions: These consensus statements may assist clinicians in the management of these difficult clinical pathologies.
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| 6. |
- Aharonian, Felix, et al.
(författare)
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Atmospheric gas dynamics in the Perseus cluster observed with Hitomi
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine the atmospheric gas motions within the central 100 kpc of the Perseus cluster using observations obtained with the Hitomi satellite. After correcting for the point spread function of the telescope and using optically thin emission lines, we find that the line-of-sight velocity dispersion of the hot gas is remarkably low and mostly uniform. The velocity dispersion reaches a maxima of approximately 200 km s(-1) toward the central active galactic nucleus (AGN) and toward the AGN inflated northwestern ghost bubble. Elsewhere within the observed region, the velocity dispersion appears constant around 100 km s(-1). We also detect a velocity gradient with a 100 km s(-1) amplitude across the cluster core, consistent with large-scale sloshing of the core gas. If the observed gas motions are isotropic, the kinetic pressure support is less than 10% of the thermal pressure support in the cluster core. The well-resolved, optically thin emission lines have Gaussian shapes, indicating that the turbulent driving scale is likely below 100 kpc, which is consistent with the size of the AGN jet inflated bubbles. We also report the first measurement of the ion temperature in the intracluster medium, which we find to be consistent with the electron temperature. In addition, we present a new measurement of the redshift of the brightest cluster galaxy NGC 1275.
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| 7. |
- Aharonian, Felix, et al.
(författare)
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Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- The Hitomi Soft X-ray Spectrometer spectrum of the Perseus cluster, with similar to 5 eV resolution in the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collisional plasmas. It reveals both successes and challenges of the current atomic data and models. The latest versions of AtomDB/APEC (3.0.8), SPEX (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band spectrum, and are in close agreement on best-fit temperature, emission measure, and abundances of a few elements such as Ni. For the Fe abundance, the APEC and SPEX measurements differ by 16%, which is 17 times higher than the statistical uncertainty. This is mostly attributed to the differences in adopted collisional excitation and dielectronic recombination rates of the strongest emission lines. We further investigate and compare the sensitivity of the derived physical parameters to the astrophysical source modeling and instrumental effects. The Hitomi results show that accurate atomic data and models are as important as the astrophysical modeling and instrumental calibration aspects. Substantial updates of atomic databases and targeted laboratory measurements are needed to get the current data and models ready for the data from the next Hitomi-level mission.
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| 8. |
- Aharonian, Felix, et al.
(författare)
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Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:6
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Tidskriftsartikel (refereegranskat)abstract
- We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray / gamma-ray sources on the sky, and, the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed the data analysis of the SGD observation, the SGD background estimation and the SGD Monte Carlo simulations, and, successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1% +/- 10.6%), and, the polarization angle is 110.degrees 7 + 13.degrees 2 /-13.degrees 0 in the energy range of 60-160 keV (The errors correspond to the 1 sigma deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124.degrees 0 +/- 0.degrees 1.
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| 9. |
- Aharonian, Felix, et al.
(författare)
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Glimpse of the highly obscured HMXB IGR J16318-4848 with Hitomi
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- We report on a Hitomi observation of IGR J16318-4848, a high-mass X-ray binary system with an extremely strong absorption of N-H similar to 10(24) cm(-2). Previous X-ray studies revealed that its spectrum is dominated by strong fluorescence lines of Fe as well as continuum emission lines. For physical and geometrical insight into the nature of the reprocessing material, we utilized the high spectroscopic resolving power of the X-ray microcalorimeter (the soft X-ray spectrometer: SXS) and the wide-band sensitivity by the soft and hard X-ray imagers (SXI and HXI) aboard Hitomi. Even though the photon counts are limited due to unintended off-axis pointing, the SXS spectrum resolves Fe K alpha(1) and K alpha(2) lines and puts strong constraints on the line centroid and line width. The line width corresponds to a velocity of 160(-70)(+300) km s(-1). This represents the most accurate, and smallest, width measurement of this line made so far from the any X-ray binary, much less than the Doppler broadening and Doppler shift expected from speeds that are characteristic of similar systems. Combined with the K-shell edge energy measured by the SXI and HXI spectra, the ionization state of Fe is estimated to be in the range of Fe I-IV. Considering the estimated ionization parameter and the distance between the X-ray source and the absorber, the density and thickness of the materials are estimated. The extraordinarily strong absorption and the absence of a Compton shoulder component have been confirmed. These characteristics suggest reprocessing materials that are distributed in a narrow solid angle or scattering, primarily by warm free electrons or neutral hydrogen. This measurement was achieved using the SXS detection of 19 photons. It provides strong motivation for follow-up observations of this and other X-ray binaries using the X-ray Astrophysics Recovery Mission and other comparable future instruments.
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| 10. |
- Aharonian, Felix, et al.
(författare)
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Hitomi observation of radio galaxy NGC 1275 : The first X-ray microcalorimeter spectroscopy of Fe-K alpha line emission from an active galactic nucleus
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- The origin of the narrow Fe-K alpha fluorescence line at 6.4 keV from active galactic nuclei has long been under debate; some of the possible sites are the outer accretion disk, the broad line region, a molecular torus, or interstellar/intracluster media. In 2016 February-March, we performed the first X-ray microcalorimeter spectroscopy with the Soft X-ray Spectrometer (SXS) on board the Hitomi satellite of the Fanaroff-Riley type I radio galaxy NGC 1275 at the center of the Perseus cluster of galaxies. With the high-energy resolution of similar to 5 eV at 6 keV achieved by Hitomi/SXS, we detected the Fe-K alpha line with similar to 5.4 sigma significance. The velocity width is constrained to be 500-1600 km s(-1) (FWHM for Gaussian models) at 90% confidence. The SXS also constrains the continuum level from the NGC 1275 nucleus up to similar to 20 keV, giving an equivalent width of similar to 20 eV for the 6.4 keV line. Because the velocity width is narrower than that of the broad H alpha line of similar to 2750 km s(-1), we can exclude a large contribution to the line flux from the accretion disk and the broad line region. Furthermore, we performed pixel map analyses on the Hitomi/SXS data and image analyses on the Chandra archival data, and revealed that the Fe-K alpha line comes from a region within similar to 1.6 kpc of the NGC 1275 core, where an active galactic nucleus emission dominates, rather than that from intracluster media. Therefore, we suggest that the source of the Fe-K alpha line from NGC 1275 is likely a low-covering-fraction molecular torus or a rotating molecular disk which probably extends from a parsec to hundreds of parsecs scale in the active galactic nucleus system.
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| 11. |
- Aharonian, Felix, et al.
(författare)
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Hitomi observations of the LMC SNR N 132 D : Highly redshifted X-ray emission from iron ejecta
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- We present Hitomi observations of N 132 D, a young, X-ray bright, O-rich core-collapse supernova remnant in the Large Magellanic Cloud (LMC). Despite a very short observation of only 3.7 ks, the Soft X-ray Spectrometer (SXS) easily detects the line complexes of highly ionized S K and Fe K with 16-17 counts in each. The Fe feature is measured for the first time at high spectral resolution. Based on the plausible assumption that the Fe K emission is dominated by He-like ions, we find that the material responsible for this Fe emission is highly redshifted at similar to 800 km s(-1) compared to the local LMC interstellar medium (ISM), with a 90% credible interval of 50-1500 km s(-1) if a weakly informative prior is placed on possible line broadening. This indicates (1) that the Fe emission arises from the supernova ejecta, and (2) that these ejecta are highly asymmetric, since no blueshifted component is found. The S K velocity is consistent with the local LMC ISM, and is likely from swept-up ISM material. These results are consistent with spatial mapping that shows the He-like Fe concentrated in the interior of the remnant and the S tracing the outer shell. The results also show that even with a very small number of counts, direct velocity measurements from Doppler-shifted lines detected in extended objects like supernova remnants are now possible. Thanks to the very low SXS background of similar to 1 event per spectral resolution element per 100 ks, such results are obtainable during short pointed or slew observations with similar instruments. This highlights the power of high-spectral-resolution imaging observations, and demonstrates the new window that has been opened with Hitomi and will be greatly widened with future missions such as the X-ray Astronomy Recovery Mission (XARM) and Athena.
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| 12. |
- Aharonian, Felix, et al.
(författare)
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Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:3
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Tidskriftsartikel (refereegranskat)abstract
- We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5-0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of Gamma(1) = 1.74 +/- 0.02 and Gamma(2) = 2.14 +/- 0.01 below and above the break at 7.1 +/- 0.3 keV, which is significantly lower than the NuSTAR result (similar to 9.0 keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833-1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 sigma. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter.
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| 13. |
- Aharonian, Felix, et al.
(författare)
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Hitomi X-ray studies of giant radio pulses from the Crab pulsar
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
-
Tidskriftsartikel (refereegranskat)abstract
- To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2-300 keV band and the Kashima NICT radio telescope in the 1.4-1.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 sigma fluctuations of the X-ray fluxes at the pulse peaks, and the 3 sigma upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2-300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.5-10 keV and 70-300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) x 10(-11) erg cm(-2), respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magneto-sphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a > 0.02% brightening of the pulse-peak flux under such conditions.
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| 14. |
- Aharonian, Felix, et al.
(författare)
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Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
-
Tidskriftsartikel (refereegranskat)abstract
- Thanks to its high spectral resolution (similar to 5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallicities and the multi-temperature structure of the gas in the core of the Perseus Cluster. Here, we show that when inferring physical properties from line emissivities in systems like Perseus, the resonant scattering effect should be taken into account. In the Hitomi waveband, resonant scattering mostly affects the Fe XXV He alpha line (w)-the strongest line in the spectrum. The flux measured by Hitomi in this line is suppressed by a factor of similar to 1.3 in the inner similar to 30 kpc, compared to predictions for an optically thin plasma; the suppression decreases with the distance from the center. The w line also appears slightly broader than other lines from the same ion. The observed distortions of the w line flux, shape, and distance dependence are all consistent with the expected effect of the resonant scattering in the Perseus core. By measuring the ratio of fluxes in optically thick (w) and thin (Fe XXV forbidden, He beta, Ly alpha) lines, and comparing these ratios with predictions from Monte Carlo radiative transfer simulations, the velocities of gas motions have been obtained. The results are consistent with the direct measurements of gas velocities from line broadening described elsewhere in this series, although the systematic and statistical uncertainties remain significant. Further improvements in the predictions of line emissivities in plasma models, and deeper observations with future X-ray missions offering similar or better capabilities to the Hitomi SXS, will enable resonant scattering measurements to provide powerful constraints on the amplitude and anisotropy of cluster gas motions.
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| 15. |
- Aharonian, Felix, et al.
(författare)
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Search for thermal X-ray features from the Crab nebula with the Hitomi soft X-ray spectrometer
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
-
Tidskriftsartikel (refereegranskat)abstract
- The Crab nebula originated from a core-collapse supernova (SN) explosion observed in 1054 AD. When viewed as a supernova remnant (SNR), it has an anomalously low observed ejecta mass and kinetic energy for an Fe-core-collapse SN. Intensive searches have been made for a massive shell that solves this discrepancy, but none has been detected. An alternative idea is that SN 1054 is an electron-capture (EC) explosion with a lower explosion energy by an order of magnitude than Fe-core-collapse SNe. X-ray imaging searches were performed for the plasma emission from the shell in the Crab outskirts to set a stringent upper limit on the X-ray emitting mass. However, the extreme brightness of the source hampers access to its vicinity. We thus employed spectroscopic technique using the X-ray micro-calorimeter on board the Hitomi satellite. By exploiting its superb energy resolution, we set an upper limit for emission or absorption features from as yet undetected thermal plasma in the 2-12 keV range. We also re-evaluated the existing Chandra and XMM-Newton data. By assembling these results, a new upper limit was obtained for the X-ray plasma mass of less than or similar to 1 M-circle dot for a wide range of assumed shell radius, size, and plasma temperature values both in and out of collisional equilibrium. To compare with the observation, we further performed hydrodynamic simulations of the Crab SNR for two SN models (Fe-core versus EC) under two SN environments (uniform interstellar medium versus progenitor wind). We found that the observed mass limit can be compatible with both SN models if the SN environment has a low density of less than or similar to 0.03 cm(-3) (Fe core) or less than or similar to 0.1 cm(-3) (EC) for the uniform density, or a progenitor wind density somewhat less than that provided by amass loss rate of 10(-5) M-circle dot yr(-1) at 20 km s(-1) for the wind environment.
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| 16. |
- Aharonian, Felix, et al.
(författare)
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Solar abundance ratios of the iron-peak elements in the Perseus cluster
- 2017
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 551:7681, s. 478-
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Tidskriftsartikel (refereegranskat)abstract
- The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae(1). Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to investigate the nature of supernova explosions integrated over cosmic time. In particular, the abundance of the iron-peak elements (chromium, manganese, iron and nickel) is key to understanding how the progenitors of typical type Ia supernovae evolve and explode(2-6). Recent X-ray studies of the intracluster medium found that the abundance ratios of these elements differ substantially from those seen in the Sun(7-11), suggesting differences between the nature of type Ia supernovae in the clusters and in the Milky Way. However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, highresolution spectroscopy is required for an accurate determination of the abundances of these elements. Here we report observations of the Perseus cluster, with statistically significant detections of the resonance emission from chromium, manganese and nickel. Our measurements, combined with the latest atomic models, reveal that these elements have near-solar abundance ratios with respect to iron, in contrast to previous claims. Comparison between our results and modern nucleosynthesis calculations(12-14) disfavours the hypothesis that type Ia supernova progenitors are exclusively white dwarfs with masses well below the Chandrasekhar limit (about 1.4 times the mass of the Sun). The observed abundance pattern of the iron-peak elements can be explained by taking into account a combination of near-and sub-Chandrasekhar-mass type Ia supernova systems, adding to the mounting evidence that both progenitor types make a substantial contribution to cosmic chemical enrichment(5,15,16).
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| 17. |
- Aharonian, Felix, et al.
(författare)
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Temperature structure in the Perseus cluster core observed with Hitomi
- 2018
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Ingår i: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Tidskriftsartikel (refereegranskat)abstract
- The present paper explains the temperature structure of X-ray emitting plasma in the core of the Perseus cluster based on 1.8-20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) on board the Hitomi Observatory. A series of four observations was carried out, with a total effective exposure time of 338 ks that covered a central region of similar to 7' in diameter. SXS was operated with an energy resolution of similar to 5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions, but also transitions from higher principal quantum numbers were clearly resolved from Si through Fe. That enabled us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single-temperature thermal plasma model in collisional ionization equilibrium, but detailed line-ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with the atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures could be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single-temperature approximation are due to the effects of projecting the known radial temperature gradient in the cluster core along the line of sight. A comparison with the Chandra/ACIS and the XMM-Newton/RGS results, on the other hand, suggests that additional lower-temperature components are present in the intracluster medium (ICM), but not detectable with Hitomi/SXS giving its 1.8-20 keV energy band.
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| 18. |
- Hayashi, Yuki, et al.
(författare)
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TOLLIP acts as a cargo adaptor to promote lysosomal degradation of aberrant ER membrane proteins
- 2023
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Ingår i: EMBO Journal. - 0261-4189 .- 1460-2075. ; 41:23
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Tidskriftsartikel (refereegranskat)abstract
- Endoplasmic reticulum (ER) proteostasis is maintained by various catabolic pathways. Lysosomes clear entire ER portions by ER-phagy, while proteasomes selectively clear misfolded or surplus aberrant proteins by ER-associated degradation (ERAD). Recently, lysosomes have also been implicated in the selective clearance of aberrant ER proteins, but the molecular basis remains unclear. Here, we show that the phosphatidylinositol-3-phosphate (PI3P)-binding proteinTOLLIP promotes selective lysosomal degradation of aberrant membrane proteins, including an artificial substrate and motoneuron disease-causing mutants of VAPB and Seipin. These cargos are recognized by TOLLIP through its misfolding-sensing intrinsically disordered region (IDR) and ubiquitin-binding CUE domain. In contrast to ER-phagy receptors, which clear both native and aberrant proteins by ER-phagy, TOLLIP selectively clears aberrant cargos by coupling them with the PI3P-dependent lysosomal trafficking without promoting bulk ER turnover. Moreover, TOLLIP depletion augments ER stress after ERAD inhibition, indicating that TOLLIP and ERAD cooperatively safeguard ER proteostasis. Our study identifies TOLLIP as a unique type of cargo-specific adaptor dedicated to the clearance of aberrant ER cargos and provides insights into molecular mechanisms underlying lysosome-mediated quality control of membrane proteins.
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| 19. |
- Ito, Y, et al.
(författare)
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Activation of c-Src is inversely correlated with biological aggressiveness of breast carcinoma
- 2002
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Ingår i: Breast Cancer Research and Treatment. - 1573-7217. ; 76:3, s. 261-267
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Tidskriftsartikel (refereegranskat)abstract
- In order to investigate whether c-Src is involved in carcinogenesis and progression of breast carcinoma, we examined the expression of activated c-Src in tissue sections from surgically resected human breast specimens. First, we confirmed the specificity of the antibody against activated c-Src (Clone 28) using six cell lines established from human breast carcinomas by western blotting. As expected, activated c-Src was detected as a 60 kDa band in all cell lines tested. Immunofluorescence analysis demonstrated that the activated c-Src was mainly observed in cytoplasms of these cells. Then, we designed an immunohistochemical study with 73 human breast carcinoma tissues. Glandular epithelial and myoepithelial cells in normal mammary glands adjacent to carcinoma nests and infiltrating stromal cells were negative for activated c-Src. In contrast, 37 of the 73 breast carcinoma tested (50.7%) were positive for activated c-Src, and this positive staining was inversely correlated with Ki-67 labeling index (p <0.0001), TNM stage (p <0.0001), tumor size (p < 0.0001), and histological grade (p = 0.0002). These results strongly suggest that the activation of c-Src would be related to the progression of breast carcinomas with low aggressiveness.
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| 20. |
- Michels, F., et al.
(författare)
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Searching for consensus in the approach to patients with chronic lateral ankle instability: ask the expert
- 2018
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Ingår i: Knee Surgery Sports Traumatology Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 26:7, s. 2095-2102
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study is to propose recommendations for the treatment of patients with chronic lateral ankle instability (CAI) based on expert opinions. A questionnaire was sent to 32 orthopaedic surgeons with clinical and scientific experience in the treatment of CAI. The questions were related to preoperative imaging, indications and timing of surgery, technical choices, and the influence of patient-related aspects. Thirty of the 32 invited surgeons (94%) responded. Consensus was found on several aspects of treatment. Preoperative MRI was routinely recommended. Surgery was considered in patients with functional ankle instability after 3-6 months of non-surgical treatment. Ligament repair is still the treatment of choice in patients with mechanical instability; however, in patients with generalized laxity or poor ligament quality, lateral ligament reconstruction (with grafting) of both the ATFL and CFL should be considered. Most surgeons request an MRI during the preoperative planning. There is a trend towards earlier surgical treatment (after failure of non-surgical treatment) in patients with mechanical ligament laxity (compared with functional instability) and in high-level athletes. This study proposes an assessment and a treatment algorithm that may be used as a recommendation in the treatment of patients with CAI.
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| 21. |
- Morokuma, Tomoki, et al.
(författare)
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Kiso Supernova Survey (KISS) : Survey strategy
- 2014
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Ingår i: Nippon Tenmon Gakkai obun kenkyu hokoku. - : Oxford University Press (OUP). - 0004-6264. ; 66:6
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Tidskriftsartikel (refereegranskat)abstract
- lThe Kiso Supernova Survey (KISS) is a high-cadence optical wide-field supernova (SN) survey. The primary goal of the survey is to catch the very early light of a SN, during the shock breakout phase. Detection of SN shock breakouts combined with multi-band photometry obtained with other facilities would provide detailed physical information on the progenitor stars of SNe. The survey is performed using a 2 degrees.2 x 2 degrees.2 field-of-view instrument on the 1.05-m Kiso Schmidt telescope, the Kiso Wide Field Camera (KWFC). We take a 3-min exposure in g-band once every hour in our survey, reaching magnitude g similar to 20-21. About 100 nights of telescope time per year have been spent on the survey since 2012 April. The number of the shock breakout detections is estimated to be of the order of 1 during our three-year project. This paper summarizes the KISS project including the KWFC observing setup, the survey strategy, the data reduction system, and CBET-reported SNe discovered so far by KISS.
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| 22. |
- Tanaka, Masaomi, et al.
(författare)
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DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421 : A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?
- 2014
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Ingår i: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 793:2, s. L26-
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Tidskriftsartikel (refereegranskat)abstract
- We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of similar to 10(7) M-circle dot implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R similar or equal to 4 x 10(2)-3 x 10(3), which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and gamma-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.
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