5,228 research outputs found
Ultrasound-guided trans-rectal high-intensity focused ultrasound (HIFU) for advanced cervical cancer ablation is feasible: a case report.
High-intensity focused ultrasound (HIFU) is an ablative treatment undergoing assessment for the treatment of benign and malignant disease. We describe the first reported intracavitary HIFU ablation for recurrent, unresectable and symptomatic cervical cancer.A 38 year old woman receiving palliative chemotherapy for metastatic cervical adenocarcinoma was offered ablative treatment from an intracavitary trans-rectal HIFU device (Sonablate® 500). Pre-treatment symptoms included vaginal bleeding and discharge that were sufficient to impede her quality of life. No peri-procedural adverse events occurred. Symptoms resolved completely immediately post-procedure, reappeared at 7 days, increasing to pre-procedural levels by day 30.This first time experience of intracavitary cervical HIFU suggests that it is feasible for palliation of advanced cervical cancer, with no early evidence of unexpected toxicity. Ethical approval had also been granted for the use of per-vaginal access if appropriate. This route, alone or in combination with the rectal route, may provide increased accessibility in future patients with a redesigned device more suited to trans-vaginal ablations.Intracavitary HIFU is a potentially safe procedure for the treatment of cervical cancer and able to provide symptomatic improvement in the palliative setting
The Half-lives of La and La
The half-lives of La and La were determined via gamma
spectroscopy and high-precision ionization chamber measurements. The results
are 18.930(6) h for La and 4.59(4) h for La compared to the
previously compiled values of 19.5(2) h and 4.8(2) h, respectively. The new
results represent an improvement in the precision and accuracy of both values.
These lanthanum isotopes comprise a medically interesting system with positron
emitter La and Auger electron emitter La forming a matched pair
for internal diagnostics and therapeutics. The precise half-lives are necessary
for proper evaluation of their value in medicine and for a more representative
tabulation of nuclear data.Comment: 11 pages, 3 figure
Computer graphics application in the engineering design integration system
The computer graphics aspect of the Engineering Design Integration (EDIN) system and its application to design problems were discussed. Three basic types of computer graphics may be used with the EDIN system for the evaluation of aerospace vehicles preliminary designs: offline graphics systems using vellum-inking or photographic processes, online graphics systems characterized by direct coupled low cost storage tube terminals with limited interactive capabilities, and a minicomputer based refresh terminal offering highly interactive capabilities. The offline line systems are characterized by high quality (resolution better than 0.254 mm) and slow turnaround (one to four days). The online systems are characterized by low cost, instant visualization of the computer results, slow line speed (300 BAUD), poor hard copy, and the early limitations on vector graphic input capabilities. The recent acquisition of the Adage 330 Graphic Display system has greatly enhanced the potential for interactive computer aided design
Fermion Masses and Mixing in Four and More Dimensions
We give an overview of recent progress in the study of fermion mass and
flavor mixing phenomena. Mass matrix ansatze are considered within the SM and
SUSY GUTs where some predictive frameworks based on SU(5) and SO(10) are
reviewed. We describe a variety of schemes to construct quark mass matrices in
extra dimensions focusing on four major classes: models with the SM residing on
3-brane, models with universal extra dimensions, models with split fermions and
models with warped extra dimensions. We outline how realistic patterns of quark
mass matrices could be derived from orbifold models in heterotic superstring
theory. Finally, we address the fermion mass problem in intersecting D-branes
scenarios, and present models with D6-branes able to give a good quantitatively
description of quark masses and mixing. The role of flavor/CP violation problem
as a probe of new physics is emphasized.Comment: a review based on seminars presented by S.K. in different places, 34
pages, late
Multiscale Gyrokinetics for Rotating Tokamak Plasmas: Fluctuations, Transport and Energy Flows
This paper presents a complete theoretical framework for plasma turbulence
and transport in tokamak plasmas. The fundamental scale separations present in
plasma turbulence are codified as an asymptotic expansion in the ratio of the
gyroradius to the equilibrium scale length. Proceeding order-by-order in this
expansion, a framework for plasma turbulence is developed. It comprises an
instantaneous equilibrium, the fluctuations driven by gradients in the
equilibrium quantities, and the transport-timescale evolution of mean profiles
of these quantities driven by the fluctuations. The equilibrium distribution
functions are local Maxwellians with each flux surface rotating toroidally as a
rigid body. The magnetic equillibrium is obtained from the Grad-Shafranov
equation for a rotating plasma and the slow (resistive) evolution of the
magnetic field is given by an evolution equation for the safety factor q.
Large-scale deviations of the distribution function from a Maxwellian are given
by neoclassical theory. The fluctuations are determined by the high-flow
gyrokinetic equation, from which we derive the governing principle for
gyrokinetic turbulence in tokamaks: the conservation and local cascade of free
energy. Transport equations for the evolution of the mean density, temperature
and flow velocity profiles are derived. These transport equations show how the
neoclassical corrections and the fluctuations act back upon the mean profiles
through fluxes and heating. The energy and entropy conservation laws for the
mean profiles are derived. Total energy is conserved and there is no net
turbulent heating. Entropy is produced by the action of fluxes flattening
gradients, Ohmic heating, and the equilibration of mean temperatures. Finally,
this framework is condensed, in the low-Mach-number limit, to a concise set of
equations suitable for numerical implementation.Comment: 113 pages, 3 figure
Rotationally Warm Molecular Hydrogen in the Orion Bar
The Orion Bar is one of the nearest and best-studied photodissociation or
photon-dominated regions (PDRs). Observations reveal the presence of H2 lines
from vibrationally or rotationally excited upper levels that suggest warm gas
temperatures (400 to 700 K). However, standard models of PDRs are unable to
reproduce such warm rotational temperatures. In this paper we attempt to
explain these observations with new comprehensive models which extend from the
H+ region through the Bar and include the magnetic field in the equation of
state. We adopt the model parameters from our previous paper which successfully
reproduced a wide variety of spectral observations across the Bar. In this
model the local cosmic-ray density is enhanced above the galactic background,
as is the magnetic field, and which increases the cosmic-ray heating elevating
the temperature in the molecular region. The pressure is further enhanced above
the gas pressure in the H+ region by the momentum transferred from the absorbed
starlight. Here we investigate whether the observed H2 lines can be reproduced
with standard assumptions concerning the grain photoelectric emission. We also
explore the effects due to the inclusion of recently computed H2 + H2, H2 + H
and H2 + He collisional rate coefficients.Comment: Accepted for publication in ApJ (34 pages, including 16 figures
Resolving the Formation of Protogalaxies. III. Feedback from the First Stars
The first stars form in dark matter halos of masses ~10^6 M_sun as suggested
by an increasing number of numerical simulations. Radiation feedback from these
stars expels most of the gas from their shallow potential well of their
surrounding dark matter halos. We use cosmological adaptive mesh refinement
simulations that include self-consistent Population III star formation and
feedback to examine the properties of assembling early dwarf galaxies. Accurate
radiative transport is modeled with adaptive ray tracing. We include supernova
explosions and follow the metal enrichment of the intergalactic medium. The
calculations focus on the formation of several dwarf galaxies and their
progenitors. In these halos, baryon fractions in 10^8 solar mass halos decrease
by a factor of 2 with stellar feedback and by a factor of 3 with supernova
explosions. We find that radiation feedback and supernova explosions increase
gaseous spin parameters up to a factor of 4 and vary with time. Stellar
feedback, supernova explosions, and H_2 cooling create a complex, multi-phase
interstellar medium whose densities and temperatures can span up to 6 orders of
magnitude at a given radius. The pair-instability supernovae of Population III
stars alone enrich the halos with virial temperatures of 10^4 K to
approximately 10^{-3} of solar metallicity. We find that 40% of the heavy
elements resides in the intergalactic medium (IGM) at the end of our
calculations. The highest metallicity gas exists in supernova remnants and very
dilute regions of the IGM.Comment: 15 pages, 16 figures, accepted to ApJ. Many changes, including
estimates of metal line cooling. High resolution images and movies available
at http://www.slac.stanford.edu/~jwise/research/PGalaxies3
Relic Neutralino Density in Scenarios with Intermediate Unification Scale
We analyse the relic neutralino density in supersymmetric models with an
intermediate unification scale. In particular, we present concrete cosmological
scenarios where the reheating temperature is as small as
MeV). When this temperature is associated to the decay of moduli fields
producing neutralinos, we show that the relic abundance increases considerably
with respect to the standard thermal production. Thus the neutralino becomes a
good dark matter candidate with 0.1\lsim \Omega h^2 \lsim 0.3, even for
regions of the parameter space where large neutralino-nucleon cross sections,
compatible with current dark matter experiments, are present. This is obtained
for intermediate scales GeV, and moduli masses
GeV. On the other hand, when the above temperature is
associated to the decay of an inflaton field, the relic abundance is too small.Comment: Latex, 11 pages, 2 figure
Liver Resection for Primary Hepatic Neoplasms.
Subtotal hepatic resection was performed in 356 patients; 87 had primary hepatic malignancies, 108 had metastatic tumors, and 161 had benign lesions including 8 traumatic injuries. The global mortality was 4.2%. The experience has elucidated the role of subtotal hepatic resection both for benign and malignant neoplasms
Trauma and Trichotillomania: A Tenuous Relationship
Some have argued that hair pulling in trichotillomania (TTM) is triggered by traumatic events, but reliable evidence linking trauma to TTM is limited. However, research has shown that hair pulling is associated with emotion regulation, suggesting a connection between negative affect and TTM. We investigated the associations between trauma, negative affect, and hair pulling in a cross-sectional sample of treatment seeking adults with TTM (N=85). In the current study, participants’ self-reported traumatic experiences were assessed during a structured clinical interview, and participants completed several measures of hair pulling severity, global TTM severity, depression, anxiety, experiential avoidance, and quality of life. Those who experienced trauma had more depressive symptoms, increased experiential avoidance, and greater global TTM severity. Although the presence of a trauma history was not related to the severity of hair pulling symptoms in the past week, depressive symptoms mediated the relationship between traumatic experiences and global TTM severity. These findings cast doubt on the notion that TTM is directly linked to trauma, but suggest that trauma leads to negative affect that individuals cope with through hair pulling. Implications for the conceptualization and treatment of TTM are discussed
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