162 research outputs found
CHARACTERISTICS AND FUNCTION OF CONNEXIN43 MUTANTS LINKED TO OCULODENTODIGITAL DYSPLASIA
Oculodentodigital dysplasia (ODDD) is a rare developmental disease that results from any one of over sixty known autosomal-dominant or autosomal-recessive mutations in the gene GJA1, which encodes for connexin43 (Cx43). In the current study, we assessed the characteristic of six Cx43 mutants, including two autosomal-dominant mutants which have been associated with bladder defects (D3N and G143S), two autosomal-dominant mutants which have not been associated with bladder defects (G2V and I130T) and two autosomal- recessive mutants (R33X and R76H). Collectively, we revealed no differences in the molecular or Cx43 channel function of the bladder disease -associated or -unassociated mutants suggesting that bladder defects linked to ODDD may be associated with other factors such as aging and/or co-morbidities. We also found that the R76H mutant could form functional channels while the R33X was functionally dead. These studies provide molecular insights into how autosomal dominant or recessive mutations affect Cx43 channel function and how Cx43 function may be linked to disease severity
The Story of [w]: An Exercise in the Phonetic Explanation for Sound Patterns
Proceedings of the 3rd Annual Meeting of the Berkeley Linguistics
Society (1977), pp. 577-59
RAVAN CubeSat Results: Technologies and Science Demonstrated On Orbit
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat, launched November 11, 2016, is a pathfinder for a constellation to measure the Earthâs energy imbalance, which is the single most important quantity for predicting the course of climate change over the next century. RAVAN demonstrates small, accurate radiometers that measure top-of-the-atmosphere Earth-leaving fluxes of total and solar-reflected energy. The radiometers rely on two key technologies. The first is the use of vertically aligned carbon nanotubes (VACNTs) as radiometer absorbers. VACNT forests are some of the blackest materials known and have an extremely flat spectral response over a wide wavelength range. The second key technology is gallium fixed-point black body calibration sources that serve as stable and repeatable references to track the long-term degradation of the sensors. Absolute calibration is maintained by regular solar and deep space views. The RAVAN payload flies on a 3U CubeSat that combines stellar attitude determination, sub-degree pointing, and UHF communication. We present the scientific motivation for the NASA-funded mission, key technologies tested in space, payload design, the 3U CubeSat bus, mission operations, instrument calibration, and the first results on-orbit
SHROOM3 is downstream of the planar cell polarity pathway and loss-of-function results in congenital heart defects
Congenital heart disease (CHD) is the most common birth defect, and the leading cause of death due to birth defects, yet causative molecular mechanisms remain mostly unknown. We previously implicated a novel CHD candidate gene, SHROOM3, in a patient with CHD. Using a Shroom3 gene trap knockout mouse (Shroom3gt/gt) we demonstrate that SHROOM3 is downstream of the noncanonical Wnt planar cell polarity signaling pathway (PCP) and loss-of-function causes cardiac defects. We demonstrate Shroom3 expression within cardiomyocytes of the ventricles and interventricular septum from E10.5 onward, as well as within cardiac neural crest cells and second heart field cells that populate the cardiac outflow tract. We demonstrate that Shroom3gt/gt mice exhibit variable penetrance of a spectrum of CHDs that include ventricular septal defects, double outlet right ventricle, and thin left ventricular myocardium. This CHD spectrum phenocopies what is observed with disrupted PCP. We show that during cardiac development SHROOM3 interacts physically and genetically with, and is downstream of, key PCP signaling component Dishevelled 2. Within Shroom3gt/gt hearts we demonstrate disrupted terminal PCP components, actomyosin cytoskeleton, cardiomyocyte polarity, organization, proliferation and morphology. Together, these data demonstrate SHROOM3 functions during cardiac development as an actomyosin cytoskeleton effector downstream of PCP signaling, revealing SHROOM3âs novel role in cardiac development and CHD
Lorentz-Abraham-Dirac vs Landau-Lifshitz radiation friction force in the ultrarelativistic electron interaction with electromagnetic wave (exact solutions)
When the parameters of electron - extreme power laser interaction enter the
regime of dominated radiation reaction, the electron dynamics changes
qualitatively. The adequate theoretical description of this regime becomes
crutially important with the use of the radiation friction force either in the
Lorentz-Abraham-Dirac form, which possess unphysical runaway solutions, or in
the Landau-Lifshitz form, which is a perturbation valid for relatively low
electromagnetic wave amplitude. The goal of the present paper is to find the
limits of the Landau-Lifshitz radiation force applicability in terms of the
electromagnetic wave amplitude and frequency. For this a class of the exact
solutions to the nonlinear problems of charged particle motion in the
time-varying electromagnetic field is used.Comment: 14 pages, 5 figure
Index of refraction, Rayleigh scattering length, and Sellmeier coefficients in solid and liquid argon and xenon
Large liquid argon detectors have become widely used in low rate experiments,
including dark matter and neutrino research. However, the optical properties of
liquid argon are not well understood at the large scales relevant for current
and near-future detectors.The index of refraction of liquid argon at the scin-
tillation wavelength has not been measured, and current Rayleigh scattering
length calculations disagree with measurements. Furthermore, the Rayleigh
scattering length and index of refraction of solid argon and solid xenon at
their scintillation wavelengths have not been previously measured or
calculated. We introduce a new calculation using existing data in liquid and
solid argon and xenon to extrapolate the optical properties at the
scintillation wavelengths using the Sellmeier dispersion relationship.Comment: 11 pages, 4 figure
Asymptotic conditions of motion for radiating charged particles
Approximate asymptotic conditions on the motion of compact, electrically
charged particles are derived within the framework of general relativity using
the Einstein- Infeld-Hoffmann (EIH) surface integral method. While
superficially similar to the Abraham-Lorentz and Lorentz-Dirac (ALD) equations
of motion, these conditions differ from them in several fundamental ways. They
are not equations of motion in the usual sense but rather a set of conditions
which these motions must obey in the asymptotic future of an initial value
surface. In addition to being asymptotic, these conditions of motion are
approximate and apply, as do the original EIH equations, only to slowly moving
systems. Also, they do not admit the run- away solutions of these other
equations. As in the original EIH work, they are integrability conditions
gotten from integrating the empty-space (i.e., source free) Einstein-Maxwell
equations of general relativity over closed two-surfaces surrounding the
sources of the fields governed by these equations. No additional ad hoc
assumptions, such as the form of a force law or the introduction of inertial
reaction terms, needed to derive the ALD equations are required for this
purpose. Nor is there a need for any of the infinite mass renormalizations that
are required in deriving these other equations.Comment: 15 page
Revisiting special relativity: A natural algebraic alternative to Minkowski spacetime
Minkowski famously introduced the concept of a space-time continuum in 1908,
merging the three dimensions of space with an imaginary time dimension , with the unit imaginary producing the correct spacetime distance , and the results of Einstein's then recently developed theory of special
relativity, thus providing an explanation for Einstein's theory in terms of the
structure of space and time. As an alternative to a planar Minkowski space-time
of two space dimensions and one time dimension, we replace the unit imaginary , with the Clifford bivector for the plane
that also squares to minus one, but which can be included without the addition
of an extra dimension, as it is an integral part of the real Cartesian plane
with the orthonormal basis and . We find that with this model of
planar spacetime, using a two-dimensional Clifford multivector, the spacetime
metric and the Lorentz transformations follow immediately as properties of the
algebra. This also leads to momentum and energy being represented as components
of a multivector and we give a new efficient derivation of Compton's scattering
formula, and a simple formulation of Dirac's and Maxwell's equations. Based on
the mathematical structure of the multivector, we produce a semi-classical
model of massive particles, which can then be viewed as the origin of the
Minkowski spacetime structure and thus a deeper explanation for relativistic
effects. We also find a new perspective on the nature of time, which is now
given a precise mathematical definition as the bivector of the plane.Comment: 29 pages, 2 figure
The Maunakea Spectroscopic Explorer Book 2018
(Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is
intended as a concise reference guide to all aspects of the scientific and
technical design of MSE, for the international astronomy and engineering
communities, and related agencies. The current version is a status report of
MSE's science goals and their practical implementation, following the System
Conceptual Design Review, held in January 2018. MSE is a planned 10-m class,
wide-field, optical and near-infrared facility, designed to enable
transformative science, while filling a critical missing gap in the emerging
international network of large-scale astronomical facilities. MSE is completely
dedicated to multi-object spectroscopy of samples of between thousands and
millions of astrophysical objects. It will lead the world in this arena, due to
its unique design capabilities: it will boast a large (11.25 m) aperture and
wide (1.52 sq. degree) field of view; it will have the capabilities to observe
at a wide range of spectral resolutions, from R2500 to R40,000, with massive
multiplexing (4332 spectra per exposure, with all spectral resolutions
available at all times), and an on-target observing efficiency of more than
80%. MSE will unveil the composition and dynamics of the faint Universe and is
designed to excel at precision studies of faint astrophysical phenomena. It
will also provide critical follow-up for multi-wavelength imaging surveys, such
as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field
Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation
Very Large Array.Comment: 5 chapters, 160 pages, 107 figure
- âŚ