Recent observational studies of core-collapse supernovae suggest that only stars with zero-age main-sequence masses smaller than 16- explode when they are red supergiants, producing Type IIP ...supernovae. This may imply that more massive stars produce other types of supernovae or they simply collapse to black holes without giving rise to bright supernovae. This failed supernova hypothesis can lead to significantly inefficient oxygen production because oxygen abundantly produced in inner layers of massive stars with zero-age main-sequence masses around 20- might not be ejected into the surrounding interstellar space. We first assume an unspecified population of oxygen injection events related to massive stars and obtain a model-independent constraint on how much oxygen should be released in a single event and how frequently such events should happen. We further carry out one-box galactic chemical enrichment calculations with different mass ranges of massive stars exploding as core-collapse supernovae. Our results suggest that the model assuming that all massive stars with 9- explode as core-collapse supernovae is still most appropriate in explaining the solar abundances of oxygen and iron and their enrichment history in the Galaxy. The oxygen mass in the Galaxy is not explained when assuming that only massive stars with zero-age main-sequence masses in the range of 9-17 contribute to the galactic oxygen enrichment. This finding implies that a good fraction of stars more massive than should eject their oxygen layers in either supernova explosions or some other mass-loss processes.
A number of astrophysical transients originating from stellar explosions are powered by the collision of the ejected material with the circumstellar medium, which efficiently produces thermal ...radiation via shock dissipation. We investigate how such interaction-powered transients are distributed in the peak bolometric luminosity versus the rise time phase space. Taking advantage of less time-consuming one-dimensional simulations with spherical symmetry, we calculated more than 500 models with different circumstellar mass and radius, ejecta mass and energy, and chemical compositions. The peak bolometric luminosity, the total radiated energy, and the rise time of the interaction-powered emission are measured for each simulated light curve. We consider how these characteristic quantities are determined as a function of the model parameters and discuss possible implications for the observed populations of (potential) interaction-powered transients, such as Type IIn supernovae and fast blue optical transients.
We perform one-dimensional radiation-hydrodynamic simulations of energetic supernova (SN) ejecta colliding with a massive circumstellar medium (CSM) aimed at explaining SN 2016aps, likely the ...brightest SN observed to date. SN 2016aps was a superluminous Type IIn SN, which released as much as erg of thermal radiation. Our results suggest that the multiband light curve of SN 2016aps is well explained by the collision of a SN ejecta with the explosion energy of 1052 erg and a wind-like CSM with the outer radius of 1016 cm, that is, a hypernova explosion embedded in a massive CSM. This finding indicates that very massive stars with initial masses larger than , which supposedly produce highly energetic SNe, occasionally eject their hydrogen-rich envelopes shortly before the core collapse. We suggest that the pulsational pair-instability SNe may provide a natural explanation for the massive CSM and the energetic explosion. We also provide the relations among the peak luminosity, the radiated energy and the rise time for interacting SNe with the kinetic energy of 1052 erg, which can be used for interpreting SN 2016aps-like objects in future surveys.
Circulatory failure is classified into four types of shock (obstructive, cardiogenic, distributive, and hypovolemic) that must be distinguished as each requires a different treatment. Point-of-care ...ultrasound (POCUS) is widely used in clinical practice for acute conditions, and several diagnostic protocols using POCUS for shock have been developed. This study aimed to evaluate the diagnostic accuracy of POCUS in identifying the etiology of shock.
We conducted a systematic literature search of MEDLINE, Cochrane Central Register of Controlled Trials, Embase, Web of Science, Clinicaltrial.gov, European Union Clinical Trials Register, WHO International Clinical Trials Registry Platform, and University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) until June 15, 2022. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and assessed study quality using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Meta-analysis was conducted to pool the diagnostic accuracy of POCUS for each type of shock. The study protocol was prospectively registered in UMIN-CTR (UMIN 000048025).
Of the 1553 studies identified, 36 studies were full-text reviewed, and 12 studies with 1132 patients were included in the meta-analysis. Pooled sensitivity and specificity were 0.82 95% confidence interval (CI) 0.68-0.91 and 0.98 95% CI 0.92-0.99 for obstructive shock, 0.78 95% CI 0.56-0.91 and 0.96 95% CI 0.92-0.98 for cardiogenic shock, 0.90 95% CI 0.84-0.94 and 0.92 95% CI 0.88-0.95 for hypovolemic shock, and 0.79 95% CI 0.71-0.85 and 0.96 95% CI 0.91-0.98 for distributive shock, respectively. The area under the receiver operating characteristic curve for each type of shock was approximately 0.95. The positive likelihood ratios for each type of shock were all greater than 10, especially 40 95% CI 11-105 for obstructive shock. The negative likelihood ratio for each type of shock was approximately 0.2.
The identification of the etiology for each type of shock using POCUS was characterized by high sensitivity and positive likelihood ratios, especially for obstructive shock.
Background:High-resolution intravascular ultrasound (HR-IVUS) is the most recently developed IVUS technology, which allows the detailed assessment of intravascular structures. The aim of this study ...was to evaluate the diagnostic performance of HR-IVUS in the detection of abnormal post-stent findings.Methods and Results:Patients with acute coronary syndrome underwent both HR-IVUS and optical coherence tomography (OCT) for post-stent evaluations. Quantitative measurements for stented segments and qualitative assessments for abnormal post-stent findings (stent edge dissection, intrastent tissue protrusion, and incomplete stent apposition ISA) were performed. Forty-seven patients underwent both HR-IVUS and OCT after stent implantation. HR-IVUS identified a larger minimal lumen area and a larger minimal lumen diameter than OCT (6.66±1.98 mm2vs. 5.61±1.79 mm2and 2.87±0.42 mm vs. 2.63±0.43 mm, respectively; both P<0.001). The sensitivity of HR-IVUS for the identification of stent edge dissection, intrastent tissue protrusion, and ISA were 20.0%, 48.9%, and 27.2%, respectively.Conclusions:In terms of post-stent evaluation, the diagnostic performance of HR-IVUS remains insufficient. Abnormal post-stent findings might be underestimated when performing HR-IVUS due to its low sensitivity.
Poly(ethylene-2,6-naphthalate) (PEN) nanofibers were prepared by carbon dioxide laser supersonic drawing (CLSD). The CLSD method was carried out by irradiating the as-spun PEN fiber with a laser in a ...low-temperature supersonic jet. The supersonic jet was generated by blowing the air from the fiber supplying orifice into a vacuum chamber. The thinnest nanofiber obtained at a laser power of 4 W and a chamber pressure of −98 kPa had an average fiber diameter of 0.249 μm. The DSC curve of this nanofiber showed two melting peaks: 260 °C and 285 °C. The higher melting temperature is 25 °C higher than the melting temperature of the original fiber. The higher melting peak is caused by an increase in the intermolecular forces in the crystallite and by the tie molecules connecting adjacent crystallites becoming fully extended. Thus, nanofibers produced by CLSD exhibit a higher melting peak, which is a unique feature. The increase in melting temperature is attributed to the supramolecular sequence effect, which is a nanoscale effect. CLSD is a new method for making nanofibers without the use of any solvent or removal of a second component.Poly(ethylene-2,6-naphthalate) (PEN) nanofibers were prepared by carbon dioxide laser supersonic drawing (CLSD). The CLSD method was carried out by irradiating the as-spun PEN fiber with a laser in a low-temperature supersonic jet, which was generated by blowing the air from the fiber supplying orifice into a vacuum chamber. The DSC curve of the PEN nanofibers produced by CLSD showed two melting peaks: 260 °C and 285 °C. The increase in melting temperature is attributed to the supramolecular sequence effect, which is a nanoscale effect.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
ABSTRACT A two-dimensional special relativistic radiation-hydrodynamics code is developed and applied to numerical simulations of supernova shock breakout in bipolar explosions of a blue supergiant. ...Our calculations successfully simulate the dynamical evolution of a blast wave in the star and its emergence from the surface. Results of the model with spherical energy deposition show a good agreement with previous simulations. Furthermore, we calculate several models with bipolar energy deposition and compare their results with the spherically symmetric model. The bolometric light curves of the shock breakout emission are calculated by a ray-tracing method. Our radiation-hydrodynamic models indicate that the early part of the shock breakout emission can be used to probe the geometry of the blast wave produced as a result of the gravitational collapse of the iron core.
We report the first demonstration of hard x-ray ptychography using a multislice approach, which can solve the problem of the limited spatial resolution under the projection approximation. We measured ...ptychographic diffraction patterns of a two-layered object with a 105 μm gap using 7 keV focused coherent x rays. We successfully reconstructed the phase map of each layer at ∼50 nm resolution using a multislice approach, while the resolution was worse than ∼192 nm under the projection approximation. The present method has the potential to enable the three-dimensional high-resolution observation of extended thick specimens in materials science and biology.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Inactivation technology for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is certainly a critical measure to mitigate the spread of coronavirus disease 2019 (COVID-19). A deep ...ultraviolet light-emitting diode (DUV-LED) would be a promising candidate to inactivate SARS-CoV-2, based on the well-known antiviral effects of DUV on microorganisms and viruses. However, due to variations in the inactivation effects across different viruses, quantitative evaluations of the inactivation profile of SARS-CoV-2 by DUV-LED irradiation need to be performed. In the present study, we quantify the irradiation dose of DUV-LED necessary to inactivate SARS-CoV-2. For this purpose, we determined the culture media suitable for the irradiation of SARS-CoV-2 and optimized the irradiation apparatus using commercially available DUV-LEDs that operate at a center wavelength of 265, 280, or 300 nm. Under these conditions, we successfully analyzed the relationship between SARS-CoV-2 infectivity and the irradiation dose of the DUV-LEDs at each wavelength without irrelevant biological effects. In conclusion, total doses of 1.8 mJ/cm
for 265 nm, 3.0 mJ/cm
for 280 nm, and 23 mJ/cm
for 300 nm are required to inactivate 99.9% of SARS-CoV-2. Our results provide quantitative antiviral effects of DUV irradiation on SARS-CoV-2, serving as basic knowledge of inactivation technologies against SARS-CoV-2.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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