7,974 research outputs found
Vapor condensation on a turbulent liquid interface
An experimental investigation which seeks the fundamental relationship between the interfacial condensation rate and the parameters which control it when the liquid side is turbulent is discussed. The scaling laws for free-surface condensation are discussed for this case. It is argued that the condensation of cryogenic liquids can, in principle, be simulated in experiments using steam and water. Data are presented for the condensation rate in terms of the dimensionless scaling parameters which involve the fluid properties and the liquid-side turbulence velocity and length scales
Repair of Aberrant Splicing in Growth Hormone Receptor by Antisense Oligonucleotides Targeting the Splice Sites of a Pseudoexon
Context: The GH receptor (GHR) pseudoexon 6 Psi defect is a frequent cause of GH insensitivity (GHI) resulting from a non-functioning GH receptor (GHR). It results in a broad range of phenotypes and may also be present in patients diagnosed as idiopathic short stature.Objective: Our objective was to correct aberrant GHR splicing and inclusion of 6 Psi using exon-skipping antisense oligonucleotides (ASOs).Design and Setting: Three ASOs binding the 5' (ASO-5), 3' (ASO-3), and branch site (ASO-Br) of 6 Psi were tested in an in vitro splicing assay and a cell transfection system. The wild-type (wt) and mutant (mt) DNA minigenes (wt- and mtL1-GHR6 Psi-L2, respectively) were created by inserting the GHR 6 Psi in a well-characterized splice reporter (Adml-par). For the in vitro splicing assay, the wt- and mtL1-GHR6 Psi-L2 were transcribed into pre-mRNA in the presence of [alpha P-32]GTP and incubated with ASOs in HeLa nuclear extracts. For the cell transfection studies, wt-and mtL1-GHR6 Psi-L2 cloned into pcDNA 3.1 were transfected with ASOs into HEK293 cells. After 48 h, RNA was extracted and radiolabeled RT-PCR products quantified.Results: ASO-3 induced an almost complete pseudoexon skipping in vitro and in HEK293 cells. This effect was dose dependent and maximal at 125-250 nM. ASO-5 produced modest pseudoexon skipping, whereas ASO-Br had no effect. Targeting of two splice elements simultaneously was less effective than targeting one. ASO-Br was tested on the wtL1-GHR6 Psi-L2 and did not act as an enhancer of 6 Psi inclusion.Conclusions: The exon-skipping ASO approach was effective in correcting aberrant GHR splicing and may be a promising therapeutic tool. (J Clin Endocrinol Metab 95: 3542-3546, 2010
Probing the gateway to superheavy nuclei in cranked relativistic Hartree-Bogoliubov theory
The cranked relativistic Hartree+Bogoliubov theory has been applied for a
systematic study of the nuclei around 254No, the heaviest nuclei for which
detailed spectroscopic data are available. The deformation, rotational
response, pairing correlations, quasi-particle and other properties of these
nuclei have been studied with different relativistic mean field (RMF)
parametrizations. For the first time, the quasi-particle spectra of odd
deformed nuclei have been calculated in a fully self-consistent way within the
framework of the RMF theory. The energies of the spherical subshells, from
which active deformed states of these nuclei emerge, are described with an
accuracy better than 0.5 MeV for most of the subshells with the NL1 and NL3
parametrizations. However, for a few subshells the discrepancy reach 0.7-1.0
MeV. The implications of these results for the study of superheavy nuclei are
discussed.Comment: 7 pages, 3 figures, Proceedings of the Conference on Frontiers of
Nuclear Structure, Berkeley, California, July 29th - August 2nd, 2002, UC
Berkeley, Clark Kerr Campus, in pres
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Molecular dynamics simulation of high frequency (1010 to 10 12 Hz) dielectric absorption in the Hollandite Nax(Ti 8-xCrx)O16
The charge-compensating sodium ions that reside interstitially in the one-dimensional tunnels of the hollandite Nax(Ti8-xCrx)O16 are used as a simple model for a fluid. Molecular dynamics are used to calculate the motions of the ions at a range of temperatures between 200 K and 373 K. The polarization response of the system to a step-up electric field is calculated for field strengths between 7.43 MV/m and 74.3 GV/m, and converted to an ac susceptibility. A resonance absorption is found,peaking at frequencies between 4.5x1010 and 8.8x1010 Hz at 297K. The origin of the response is shown to be the anharmonically coupled ion vibrations damped by ion hopping to neighbouring sites. The relationship of the result to the experimentally observed Poley absorption is explored, and a brief comparison of the calculated dynamics to previous theoretical models is made
Opto-optical modulation in N-(p-methoxybenzylidene)-p-butylaniline
A method of opto-optical modulation in liquid crystals is reported. An Ar+-laser beam is employed to modulate a second He–Ne laser. The highest frequency achieved was 1.5 × 103 pulses per second with input modulating powers smaller than 10 mW. A homeotropic N-(p-methoxybenzylidene)-p-butylaniline liquid-crystal cell was employed as the nonlinear medium
Quantum Walks on Trees with Disorder: Decay, Diffusion, and Localization
Quantum walks have been shown to have impressive transport properties
compared to classical random walks. However, imperfections in the quantum walk
algorithm can destroy any quantum mechanical speed-up due to Anderson
localization. We numerically study the effect of static disorder on a quantum
walk on the glued trees graph. For small disorder, we find that the dominant
effect is a type of quantum decay, and not quantum localization. For
intermediate disorder, there is a crossover to diffusive transport, while a
localization transition is observed at large disorder, in agreement with
Anderson localization on the Cayley tree.Comment: 12 pages, 13 figure
Liquid crystal hyperbolic metamaterial for wide-angle negative-positive refraction and reflection
We show that nanosphere dispersed liquid crystal (NDLC) metamaterial can be
characterized in near IR spectral region as an indefinite medium whose real
parts of effective ordinary and extraordinary permittivities are opposite in
signs. Based on this fact we design a novel electrooptic effect: external
electric field driven switch between normal refraction, negative refraction and
reflection of TM incident electromagnetic wave from the boundary vacuum/NDLC. A
detailed analysis of its functionality is given based on effective medium
theory combined with a study of negative refraction in anisotropic
metamaterials, and Finite Elements simulations
Ultrafast Optical Signal Processing with Bragg Structures
The phase, amplitude, speed, and polarization, in addition to many other
properties of light, can be modulated by photonic Bragg structures. In
conjunction with nonlinearity and quantum effects, a variety of ensuing micro-
or nano-photonic applications can be realized. This paper reviews various
optical phenomena in several exemplary 1D Bragg gratings. Important examples
are resonantly absorbing photonic structures, chirped Bragg grating, and
cholesteric liquid crystals; their unique operation capabilities and key issues
are considered in detail. These Bragg structures are expected to be used in
wide-spread applications involving light field modulations, especially in the
rapidly advancing field of ultrafast optical signal processing.Comment: To be published in a special issue of journal Applied Sciences, on
the topic of Guided-Wave Optic
Splicing therapeutics in SMN2 and APOB
Splicing therapeutics are defined as the deliberate modification of RNA splicing to achieve therapeutic goals. Various techniques for splicing therapeutics have been described, and most of these involve the use of antisense oligonucleotide-based compounds that target key elements in the pre-mRNA to control splicing in the nucleus. In this review, recent developments in splicing therapeutics for the treatment of two specific diseases are described: correcting the alternative splicing of survival of motor neuron (SMN)2 pre-mRNA to compensate for the defective SMN1 gene in spinal muscular atrophy, and re-engineering the splicing of apolipoprotein B pre-mRNA to lower circulating cholesterol levels
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