| 1221. |
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| 1222. |
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| 1223. |
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| 1224. |
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| 1225. |
- Milisavljevic, D., et al.
(författare)
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METAMORPHOSIS OF SN 2014C : DELAYED INTERACTION BETWEEN A HYDROGEN POOR CORE-COLLAPSE SUPERNOVA AND A NEARBY CIRCUMSTELLAR SHELL
- 2015
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 815:2
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Tidskriftsartikel (refereegranskat)abstract
- We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent with the supernova having exploded in a cavity before encountering a massive shell of the progenitor star's stripped hydrogen envelope. Possible origins for the circumstellar shell include a brief Wolf-Rayet fast wind phase that overtook a slower red supergiant wind, eruptive ejection, or confinement of circumstellar material by external influences of neighboring stars. An extended high velocity Ha absorption feature seen in near-maximum light spectra implies that the progenitor star was not completely stripped of hydrogen at the time of core collapse. Archival pre-explosion Subaru Telescope Suprime-Cam and Hubble Space Telescope Wide Field Planetary Camera. 2 images of the region obtained in 2009 show a coincident source that is most likely a compact massive star cluster in NGC 7331 that hosted the progenitor system. By comparing the emission properties of the source with stellar population models that incorporate interacting binary stars we estimate the age of the host cluster to be 30-300 Myr, and favor ages closer to 30 Myr in light of relatively strong Ha emission. SN 2014C is the best observed member of a class of core-collapse supernovae that fill the gap between events that interact strongly with dense, nearby environments immediately after explosion and those that never show signs of interaction. Better understanding of the frequency and nature of this intermediate population can contribute valuable information about the poorly understood final stages of stellar evolution.
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| 1226. |
- Miller, A. A., et al.
(författare)
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Early Observations of the Type Ia Supernova iPTF 16abc : A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 852:2
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Tidskriftsartikel (refereegranskat)abstract
- Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is, when the SN could have first been detected by our survey, occurred only 0.15 +/-(0.15)(0.07) days before our first detection. In the similar to 24 hr after discovery, iPTF 16abc rose by similar to 2mag, featuring a near-linear rise in flux for. greater than or similar to 3 days. Early spectra show strong C II absorption, which disappears after similar to 7 days. Unlike the extensively observed Type Ia SN 2011fe, the (B - V)(0) colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive Ni-56 in the SN ejecta, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.
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| 1227. |
- Miller, A, et al.
(författare)
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A super-potent tetramerized ACE2 protein displays enhanced neutralization of SARS-CoV-2 virus infection
- 2021
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1, s. 10617-
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Tidskriftsartikel (refereegranskat)abstract
- Approaches are needed for therapy of the severe acute respiratory syndrome from SARS-CoV-2 coronavirus (COVID-19). Interfering with the interaction of viral antigens with the angiotensin converting enzyme 2 (ACE-2) receptor is a promising strategy by blocking the infection of the coronaviruses into human cells. We have implemented a novel protein engineering technology to produce a super-potent tetravalent form of ACE2, coupled to the human immunoglobulin γ1 Fc region, using a self-assembling, tetramerization domain from p53 protein. This high molecular weight Quad protein (ACE2-Fc-TD) retains binding to the SARS-CoV-2 receptor binding spike protein and can form a complex with the spike protein plus anti-viral antibodies. The ACE2-Fc-TD acts as a powerful decoy protein that out-performs soluble monomeric and dimeric ACE2 proteins and blocks both SARS-CoV-2 pseudovirus and SARS-CoV-2 virus infection with greatly enhanced efficacy. The ACE2 tetrameric protein complex promise to be important for development as decoy therapeutic proteins against COVID-19. In contrast to monoclonal antibodies, ACE2 decoy is unlikely to be affected by mutations in SARS-CoV-2 that are beginning to appear in variant forms. In addition, ACE2 multimeric proteins will be available as therapeutic proteins should new coronaviruses appear in the future because these are likely to interact with ACE2 receptor.
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| 1228. |
- Miller, A. M., et al.
(författare)
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Multicenter immunoassay validation of cerebrospinal fluid neurofilament light: a biomarker for neurodegeneration
- 2016
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Ingår i: Bioanalysis. - : Future Science Ltd. - 1757-6180 .- 1757-6199. ; 8:21, s. 2243-2254
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Neurofilament light (NfL) chain, a putative cerebrospinal fluid biomarker, can support neurodegenerative disease diagnosis and indicate disease severity and prognosis. Universal validation protocols when used to measure biomarkers can reduce pre and analytical laboratory variation, thus increasing end-user confidence in the consistency of validation data across sites. Methodology: Here, a commercially available NfL ELISA (UmanDiagnostics, Ume dagger, Sweden) was validated in a multicentered setting using comprehensive newly developed standard operating procedures. Results: The data showed good assay sensitivity and intra and interassay precision. Interlaboratory precision was, however, suboptimal. Conclusion: The UmanDiagnostics assay is suitable for the quantification of NfL in human cerebrospinal fluid. However, sources of interlaboratory variation in the data require further investigation.
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| 1229. |
- Miller, Hayley V., et al.
(författare)
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The mirror-based eyes of scallops demonstrate a light-evoked pupillary response
- 2019
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822. ; 29:9, s. 313-314
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Tidskriftsartikel (refereegranskat)abstract
- Light levels in terrestrial and shallow-water environments can vary by ten orders of magnitude between clear days and overcast nights. Light-evoked pupillary responses help the eyes of animals perform optimally under these variable light conditions by balancing trade-offs between sensitivity and resolution [1]. Here, we document that the mirror-based eyes of the bay scallop Argopecten irradians and the sea scallop Placopecten magellanicus have pupils that constrict to ∼60% of their fully dilated areas within several minutes of light exposure. The eyes of scallops contain two separate retinas and our ray-tracing model indicates that, compared to eyes with fully constricted pupils, eyes from A. irradians with fully dilated pupils provide approximately three times the sensitivity and half the spatial resolution at the distal retina and five times the sensitivity and one third the spatial resolution at the proximal retina. We also identify radial and circular actin fibers associated with the corneas of A. irradians that may represent muscles whose contractions dilate and constrict the pupil, respectively. Miller et al. report that the mirror-based eyes of two species of scallop have pupils that constrict to ∼60% of their fully dilated areas within several minutes of being exposed to light. At the cost of sensitivity, narrower pupils improve spatial resolution in the eyes of scallops by decreasing the influence of optical aberrations.
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| 1230. |
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