74 research outputs found
High-efficiency endovascular gene delivery via therapeutic ultrasound
AbstractOBJECTIVESWe studied enhancement of local gene delivery to the arterial wall by using an endovascular catheter ultrasound (US).BACKGROUNDUltrasound exposure is standard for enhancement of in vitro gene delivery. We postulate that in vivo endovascular applications can be safely developed.METHODSWe used a rabbit model of arterial mechanical overdilation injury. After arterial overdilation, US catheters were introduced in bilateral rabbit femoral arteries and perfused with plasmid- or adenovirus-expressing blue fluorescent protein (BFP) or phosphate buffered saline. One side received endovascular US (2 MHz, 50 W/cm2, 16 min), and the contralateral artery did not.RESULTSRelative to controls, US exposure enhanced BFP expression measured via fluorescence 12-fold for plasmid (1,502.1 ± 927.3 vs. 18,053.9 ± 11,612 μm2, p < 0.05) and 19-fold for adenovirus (877.1 ± 577.7 vs. 17,213.15 ± 3,892 μm2, p < 0.05) while increasing cell death for the adenovirus group only (26 ± 5.78% vs. 13 ± 2.55%, p < 0.012).CONCLUSIONSEndovascular US enhanced vascular gene delivery and increased the efficiency of nonviral platforms to levels previously attained only by adenoviral strategies
Phase Stability of Hexagonal/cubic Boron Nitride Nanocomposites
Boron nitride (BN) is an exceptional material and among its polymorphs,
two-dimensional (2D) hexagonal and three-dimensional (3D) cubic BN (h-BN and
c-BN) phases are most common. The phase stability regimes of these BN phases
are still under debate and phase transformations of h-BN/c-BN remain a topic of
interest. Here, we investigate the phase stability of 2D/3D h-BN/c-BN
nanocomposites and show that the co-existence of two phases can lead to strong
non-linear optical properties and low thermal conductivity at room temperature.
Furthermore, spark-plasma sintering of the nanocomposite shows complete phase
transformation to 2D h-BN with improved crystalline quality, where 3D c-BN
grain sizes governs the nucleation and growth kinetics. Our demonstration might
be insightful in phase engineering of BN polymorphs based nanocomposites with
desirable properties for optoelectronics and thermal energy management
applications.Comment: 29 pages, 5 figure
Highly Volcanic Exoplanets, Lava Worlds, and Magma Ocean Worlds:An Emerging Class of Dynamic Exoplanets of Significant Scientific Priority
Highly volcanic exoplanets, which can be variously characterized as 'lava
worlds', 'magma ocean worlds', or 'super-Ios' are high priority targets for
investigation. The term 'lava world' may refer to any planet with extensive
surface lava lakes, while the term 'magma ocean world' refers to planets with
global or hemispherical magma oceans at their surface. 'Highly volcanic
planets', including super-Ios, may simply have large, or large numbers of,
active explosive or extrusive volcanoes of any form. They are plausibly highly
diverse, with magmatic processes across a wide range of compositions,
temperatures, activity rates, volcanic eruption styles, and background
gravitational force magnitudes. Worlds in all these classes are likely to be
the most characterizable rocky exoplanets in the near future due to
observational advantages that stem from their preferential occurrence in short
orbital periods and their bright day-side flux in the infrared. Transit
techniques should enable a level of characterization of these worlds analogous
to hot Jupiters. Understanding processes on highly volcanic worlds is critical
to interpret imminent observations. The physical states of these worlds are
likely to inform not just geodynamic processes, but also planet formation, and
phenomena crucial to habitability. Volcanic and magmatic activity uniquely
allows chemical investigation of otherwise spectroscopically inaccessible
interior compositions. These worlds will be vital to assess the degree to which
planetary interior element abundances compare to their stellar hosts, and may
also offer pathways to study both the very young Earth, and the very early form
of many silicate planets where magma oceans and surface lava lakes are expected
to be more prevalent. We suggest that highly volcanic worlds may become second
only to habitable worlds in terms of both scientific and public long-term
interest.Comment: A white paper submitted in response to the National Academy of
Sciences 2018 Exoplanet Science Strategy solicitation, from the NASA Sellers
Exoplanet Environments Collaboration (SEEC) of the Goddard Space Flight
Center. 6 pages, 0 figure
Exoplanet Science Priorities from the Perspective of Internal and Surface Processes for Silicate and Ice Dominated Worlds
The geophysics of extrasolar planets is a scientific topic often regarded as
standing largely beyond the reach of near-term observations. This reality in no
way diminishes the central role of geophysical phenomena in shaping planetary
outcomes, from formation, to thermal and chemical evolution, to numerous issues
of surface and near-surface habitability. We emphasize that for a balanced
understanding of extrasolar planets, it is important to look beyond the natural
biases of current observing tools, and actively seek unique pathways to
understand exoplanet interiors as best as possible during the long interim
prior to a time when internal components are more directly accessible. Such
pathways include but are not limited to: (a) enhanced theoretical and numerical
modeling, (b) laboratory research on critical material properties, (c)
measurement of geophysical properties by indirect inference from imprints left
on atmospheric and orbital properties, and (d) the purpose-driven use of Solar
System object exploration expressly for its value in comparative planetology
toward exoplanet-analogs. Breaking down barriers that envision local Solar
System exploration, including the study of Earth's own deep interior, as
separate from and in financial competition with extrasolar planet research, may
greatly improve the rate of needed scientific progress for exoplanet
geophysics. As the number of known rocky and icy exoplanets grows in the years
ahead, we expect demand for expertise in 'exogeoscience' will expand at a
commensurately intense pace. We highlight key topics, including: how water
oceans below ice shells may dominate the total habitability of our galaxy by
volume, how free-floating nomad planets may often attain habitable subsurface
oceans supported by radionuclide decay, and how deep interiors may critically
interact with atmospheric mass loss via dynamo-driven magnetic fields
Whole-body phase angle correlates with pre-operative markers in total joint arthroplasty
Bioimpedance derived whole body phase angle (Ï•), a measure of cellular integrity, has been identified as an independent marker of morbidity and mortality in many medical and surgical specialties. While similar measures of water homeostasis like extracellular edema (EE) have been associated with pre-operative risk, Ï• has not been studied in orthopaedics, despite potential to serve as a pre-operative marker. This study aims to identify relationships between Ï•, EE, and body composition metrics, laboratory values, patient reported outcomes, and comorbidities
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