896 research outputs found
Akinesia becoming dyskinesia during exercise echocardiography: Prevalence and relationship to clinical outcome
Fission yeast Lem2 and Man1 perform fundamental functions of the animal cell nuclear lamina
In animal cells the nuclear lamina, which consists of lamins and lamin-associated proteins, serves several functions: it provides a structural scaffold for the nuclear envelope and tethers proteins and heterochromatin to the nuclear periphery. In yeast, proteins and large heterochromatic domains including telomeres are also peripherally localized, but there is no evidence that yeast have lamins or a fibrous nuclear envelope scaffold. Nonetheless, we found that the Lem2 and Man1 proteins of the fission yeast Schizosaccharomyces pombe, evolutionarily distant relatives of the Lap2/Emerin/Man1 (LEM) sub-family of animal cell lamin-associated proteins, perform fundamental functions of the animal cell lamina. These integral inner nuclear membrane localized proteins, with nuclear localized DNA binding Helix-Extension-Helix (HEH) domains, impact nuclear envelope structure and integrity, are essential for the enrichment of telomeres at the nuclear periphery and by means of their HEH domains anchor chromatin, most likely transcriptionally repressed heterochromatin, to the nuclear periphery. These data indicate that the core functions of the nuclear lamina are conserved between fungi and animal cells and can be performed in fission yeast, without lamins or other intermediate filament proteins
The progenitor and early evolution of the Type IIb SN 2016gkg
We report initial observations and analysis on the Type IIb SN~2016gkg in the
nearby galaxy NGC~613. SN~2016gkg exhibited a clear double-peaked light curve
during its early evolution, as evidenced by our intensive photometric follow-up
campaign. SN~2016gkg shows strong similarities with other Type IIb SNe, in
particular with respect to the \he~emission features observed in both the
optical and near infrared. SN~2016gkg evolved faster than the prototypical
Type~IIb SN~1993J, with a decline similar to that of SN~2011dh after the first
peak. The analysis of archival {\it Hubble Space Telescope} images indicate a
pre-explosion source at SN~2016gkg's position, suggesting a progenitor star
with a mid F spectral type and initial mass \msun, depending on
the distance modulus adopted for NGC~613. Modeling the temperature evolution
within of explosion, we obtain a progenitor radius of
\rsun, smaller than that obtained from the analysis of the
pre-explosion images (\rsun).Comment: 7 pages, 5 figures. Submitted to ApJ Letter
Development of a Time Efficient Protocol for Cross-Limb Comparisons of Muscle Mitochondrial Capacity Using NIRS
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SN 2015ba: A type IIP supernova with a long plateau
We present optical photometry and spectroscopy from about a week after
explosion to 272 d of an atypical Type IIP supernova, SN 2015ba, which
exploded in the edge-on galaxy IC 1029. SN 2015ba is a luminous event with an
absolute V-band magnitude of -17.10.2 mag at 50 d since explosion and has
a long plateau lasting for 123 d. The distance to the SN is estimated to
be 34.80.7 Mpc using the expanding photosphere and standard candle
methods. High-velocity H-Balmer components constant with time are observed in
the late-plateau phase spectra of SN 2015ba, which suggests a possible role of
circumstellar interaction at these phases. Both hydrodynamical and analytical
modelling suggest a massive progenitor of SN 2015ba with a pre-explosion mass
of 24-26 M. However, the nebular spectra of SN 2015ba exhibit
insignificant levels of oxygen, which is otherwise expected from a massive
progenitor. This might be suggestive of the non-monotonical link between O-core
masses and the zero-age main-sequence mass of pre-supernova stars and/or
uncertainties in the mixing scenario in the ejecta of supernovae.Comment: 42 pages, 7 pages Appendix, 20 figures, 10 tables, Accepted for
publication in MNRAS, 14-June-201
Typical blood pressure response during dobutamine stress echocardiography of patients without known cardiovascular disease who have normal stress echocardiograms
Contractile properties of the muscles of mastication of rhesus monkeys (Macaca mulatta) following increase in muscle length
The hypothesis was tested that increasing the resting length of the masseter and temporalis muscles by a bite-opening appliance with or without detachment and re-attachment of the masseter would not affect the contractile properties of these muscles. Appliances opened the bite of 10 adult female monkeys 20mm. Five received the appliance alone (Group A); five received the appliance and in addition the masseter was detached and re-attached (Group ADR). Comparisons were made 48 weeks later. Small bundles of fibres were excised from the masseter and temporalis muscles of experimental animals and from 8 control animals. Isometric and isotonic contractile properties were measured in vitro and fibre classification and fibre areas were determined histochemically. No significant differences were observed within either masseter or temporalis muscles between animals in Groups A and ADR. In both groups, the bundles of fibres from the masseter had prolonged contraction and relaxation times compared to control masseter muscles but no difference was observed in the percentage of Type II fibres. As detachment and re-attachment had no significant effect on morphological or physiological characteristics, other than those due to lengthening, this procedure may be useful in decreasing the passive tension induced when orthognathic surgery increases muscle length. The significant prolongation of the contractile response of the masseter is similar to the adaptation induced by long-term stimulation at low frequency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24139/1/0000396.pd
SN Refsdal: Classification as a Luminous and Blue SN 1987A-like Type II Supernova
We have acquired Hubble Space Telescope (HST) and Very Large Telescope
near-infrared spectra and images of supernova (SN) Refsdal after its discovery
as an Einstein cross in Fall 2014. The HST light curve of SN Refsdal matches
the distinctive, slowly rising light curves of SN 1987A-like supernovae (SNe),
and we find strong evidence for a broad H-alpha P-Cygni profile in the HST
grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn,
powered by circumstellar interaction, could provide a good match to the light
curve of SN Refsdal, but the spectrum of a SN IIn would not show broad and
strong H-alpha absorption. From the grism spectrum, we measure an H-alpha
expansion velocity consistent with those of SN 1987A-like SNe at a similar
phase. The luminosity, evolution, and Gaussian profile of the H-alpha emission
of the WFC3 and X-shooter spectra, separated by ~2.5 months in the rest frame,
provide additional evidence that supports the SN 1987A-like classification. In
comparison with other examples of SN 1987A-like SNe, SN Refsdal has a blue B-V
color and a high luminosity for the assumed range of potential magnifications.
If SN Refsdal can be modeled as a scaled version of SN 1987A, we estimate it
would have an ejecta mass of 20+-5 solar masses. The evolution of the light
curve at late times will provide additional evidence about the potential
existence of any substantial circumstellar material (CSM). Using MOSFIRE and
X-shooter spectra, we estimate a subsolar host-galaxy metallicity (8.3+-0.1 dex
and <8.4 dex, respectively) near the explosion site.Comment: Submitted to ApJ; 26 page
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