375 research outputs found
Generation of Closed Timelike Curves with Rotating Superconductors
The spacetime metric around a rotating SuperConductive Ring (SCR) is deduced
from the gravitomagnetic London moment in rotating superconductors. It is shown
that theoretically it is possible to generate Closed Timelike Curves (CTC) with
rotating SCRs. The possibility to use these CTC's to travel in time as
initially idealized by G\"{o}del is investigated. It is shown however, that
from a technology and experimental point of view these ideas are impossible to
implement in the present context.Comment: 9 pages. Submitted to Classical and Quantum Gravit
Generalized "Quasi-classical" Ground State for an Interacting Two Level System
We treat a system (a molecule or a solid) in which electrons are coupled
linearly to any number and type of harmonic oscillators and which is further
subject to external forces of arbitrary symmetry. With the treatment restricted
to the lowest pair of electronic states, approximate "vibronic"
(vibration-electronic) ground state wave functions are constructed having the
form of simple, closed expressions. The basis of the method is to regard
electronic density operators as classical variables. It extends an earlier
"guessed solution", devised for the dynamical Jahn-Teller effect in cubic
symmetry, to situations having lower (e.g., dihedral) symmetry or without any
symmetry at all. While the proposed solution is expected to be quite close to
the exact one, its formal simplicity allows straightforward calculations of
several interesting quantities, like energies and vibronic reduction (or Ham)
factors. We calculate for dihedral symmetry two different -factors (""
and "") and a -factor. In simplified situations we obtain . The formalism enables quantitative estimates to be made for the dynamical
narrowing of hyperfine lines in the observed ESR spectrum of the dihedral
cyclobutane radical cation.Comment: 28 pages, 4 figure
A Variational Procedure for Time-Dependent Processes
A simple variational Lagrangian is proposed for the time development of an
arbitrary density matrix, employing the "factorization" of the density. Only
the "kinetic energy" appears in the Lagrangian. The formalism applies to pure
and mixed state cases, the Navier-Stokes equations of hydrodynamics, transport
theory, etc. It recaptures the Least Dissipation Function condition of
Rayleigh-Onsager {\bf and in practical applications is flexible}. The
variational proposal is tested on a two level system interacting that is
subject, in one instance, to an interaction with a single oscillator and, in
another, that evolves in a dissipative mode.Comment: 25 pages, 4 figure
Radiation measurements in the new tandem accelerator FEL
The measurements of both spontaneous and stimulated emissions of radiation in
the newly configured Israeli EA-FEL are made for the first time. The radiation
at the W-band was measured and characterized. The results match the predictions
of our earlier theoretical modeling and calculations.Comment: 4 pages, 3 figures, FEL 2003 Conference repor
Therapeutic efficacy in a hemophilia B model using a biosynthetic mRNA liver depot system
DNA-based gene therapy has considerable therapeutic potential, but the challenges associated with delivery continue to limit progress. Messenger RNA (mRNA) has the potential to provide for transient production of therapeutic proteins, without the need for nuclear delivery and without the risk of insertional mutagenesis. Here we describe the sustained delivery of therapeutic proteins in vivo in both rodents and non-human primates via nanoparticle-formulated mRNA. Nanoparticles formulated with lipids and lipid-like materials were developed for delivery of two separate mRNA transcripts encoding either human erythropoietin (hEPO) or factor IX (hFIX) protein. Dose-dependent protein production was observed for each mRNA construct. Upon delivery of hEPO mRNA in mice, serum EPO protein levels reached several orders of magnitude (>125 000-fold) over normal physiological values. Further, an increase in hematocrit (Hct) was established, demonstrating that the exogenous mRNA-derived protein maintained normal activity. The capacity of producing EPO in non-human primates via delivery of formulated mRNA was also demonstrated as elevated EPO protein levels were observed over a 72-h time course. Exemplifying the possible broad utility of mRNA drugs, therapeutically relevant amounts of human FIX (hFIX) protein were achieved upon a single intravenous dose of hFIX mRNA-loaded lipid nanoparticles in mice. In addition, therapeutic value was established within a hemophilia B (FIX knockout (KO)) mouse model by demonstrating a marked reduction in Hct loss following injury (incision) to FIX KO mice
Two distinct prognostic groups in advanced-stage Hodgkin lymphoma revealed by the presence and site of bulky disease
Tetrodotoxin-Bupivacaine-Epinephrine Combinations for Prolonged Local Anesthesia
Currently available local anesthetics have analgesic durations in humans generally less than 12 hours. Prolonged-duration local anesthetics will be useful for postoperative analgesia. Previous studies showed that in rats, combinations of tetrodotoxin (TTX) with bupivacaine had supra-additive effects on sciatic block durations. In those studies, epinephrine combined with TTX prolonged blocks more than 10-fold, while reducing systemic toxicity. TTX, formulated as Tectin, is in phase III clinical trials as an injectable systemic analgesic for chronic cancer pain. Here, we examine dose-duration relationships and sciatic nerve histology following local nerve blocks with combinations of Tectin with bupivacaine 0.25% (2.5 mg/mL) solutions, with or without epinephrine 5 µg/mL (1:200,000) in rats. Percutaneous sciatic blockade was performed in Sprague-Dawley rats, and intensity and duration of sensory blockade was tested blindly with different Tectin-bupivacaine-epinephrine combinations. Between-group comparisons were analyzed using ANOVA and post-hoc Sidak tests. Nerves were examined blindly for signs of injury. Blocks containing bupivacaine 0.25% with Tectin 10 µM and epinephrine 5 µg/mL were prolonged by roughly 3-fold compared to blocks with bupivacaine 0.25% plain (P < 0.001) or bupivacaine 0.25% with epinephrine 5 µg/mL (P < 0.001). Nerve histology was benign for all groups. Combinations of Tectin in bupivacaine 0.25% with epinephrine 5 µg/mL appear promising for prolonged duration of local anesthesia
Influence of different treatment techniques on radiation dose to the LAD coronary artery
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Analysis of common and rare VPS13C variants in late-onset Parkinson disease
Objective
We aimed to study the role of coding VPS13C variants in a large cohort of patients with lateonset Parkinson disease (PD) (LOPD).
Methods
VPS13C and its untranslated regions were sequenced using targeted next-generation sequencing in 1,567 patients with PD and 1,667 controls from 3 cohorts. Association tests of rare
potential homozygous and compound heterozygous variants and burden tests for rare heterozygous variants were performed. Common variants were analyzed using logistic regression
adjusted for age and sex in each of the cohorts, followed by a meta-analysis.
Results
No biallelic carriers of rare VPS13C variants were found among patients, and 2 carriers of
compound heterozygous variants were found in 2 controls. There was no statistically significant
burden of rare (minor allele frequency [MAF] <1%) or very rare (MAF <0.1%) coding VPS13C
variants in PD. A VPS13C haplotype including the p.R153H-p.I398I-p.I1132V-p.Q2376Q
variants was nominally associated with a reduced risk for PD (meta-analysis of the tagging SNP
p.I1132V [odds ratio = 0.48, 95% confidence interval = 0.28–0.82, p = 0.0052]). This haplotype
was not in linkage disequilibrium with the known genome-wide association study top hit.
Conclusions
Our results do not support a role for rare heterozygous or biallelic VPS13C variants in LOPD.
Additional genetic replication and functional studies are needed to examine the role of the
haplotype identified here associated with reduced risk for PD
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