895 research outputs found
Prä- und posttherapeutische Larynxbildgebung
Zusammenfassung: Sowohl CT als auch MRT und neuerdings die PET-CT sind unentbehrliche Zusatzuntersuchungen zur Diagnostik und Stadieneinteilung von Tumoren des Larynx. Sie sind der klinischen Untersuchung (einschließlich endoskopischer Biopsie) beigeordnet und ergänzen diese komplementär. Eine sehr genaue Kenntnis der submukösen Tumorausbreitungswege, der diagnostischen Zeichen der Tumorinfiltration und deren Konsequenzen für Stadieneinteilung und Therapie sind unentbehrlich für die Interpretation von CT-, MRT- und PET-CT-Bildern. Sowohl CT als auch MRT sind hochsensitive Untersuchungen zum Nachweis der neoplastischen Infiltration des präepi- und paraglottischen Raums, der Subglottis und des Knorpels. Die Spezifität ist jedoch mit beiden Methoden weniger hoch als zunächst erwartet, wodurch eine Tendenz zum Überschätzen der Tumorausbreitung resultiert. Neuere Untersuchungen haben jedoch gezeigt, dass die Spezifität der MRT mittels Anwendung neuer diagnostischer Kriterien signifikant verbessert werden kann, da eine Unterscheidung zwischen Tumor und peritumoraler Entzündung in vielen Fällen möglich ist. Der sehr hohe negative Vorhersagewert der beiden Schnittbildverfahren ist aus klinischer Sicht wichtig, da er es ermöglicht, die neoplastische Knorpelinfiltration auszuschließen. Beide Methoden verbessern signifikant die prätherapeutische Stagingtreffsicherheit, wenn sie zusätzlich zur Endoskopie eingesetzt werden. Bei submukösen Tumoren liefern sowohl CT als auch MRT wertvolle Hinweise auf eine mögliche Ätiologie, auf das Ausmaß des submukösen Wachstums und die geeignete Biopsiestelle. Sie spielen auch eine wichtige Rolle bei der Diagnose von Laryngozelen, der Abklärung von N.-laryngeus-recurrens-Paresen und Larynxfrakture
Mucoid morphotype variation of Burkholderia multivorans during chronic cystic fibrosis lung infection is correlated with changes in metabolism, motility, biofilm formation and virulence
Burkholderia cepacia complex (Bcc) bacteria are opportunistic pathogens infecting hosts such as cystic fibrosis (CF) patients. Long-term Bcc infection of CF patients' airways has been associated with emergence of phenotypic variation. Here we studied two Burkholderia multivorans clonal isolates displaying different morphotypes from a chronically infected CF patient to evaluate trait development during lung infection. Expression profiling of mucoid D2095 and non-mucoid D2214 isolates revealed decreased expression of genes encoding products related to virulence-associated traits and metabolism in D2214. Furthermore, D2214 showed no exopolysaccharide production, lower motility and chemotaxis, and more biofilm formation, particularly under microaerophilic conditions, than the clonal mucoid isolate D2095. When Galleria mellonella was used as acute infection model, D2214 at a cell number of approximately 7×10(6) c.f.u. caused a higher survival rate than D2095, although 6 days post-infection most of the larvae were dead. Infection with the same number of cells by mucoid D2095 caused larval death by day 4. The decreased expression of genes involved in carbon and nitrogen metabolism may reflect lower metabolic needs of D2214 caused by lack of exopolysaccharide, but also by the attenuation of pathways not required for survival. As a result, D2214 showed higher survival than D2095 in minimal medium for 28 days under aerobic conditions. Overall, adaptation during Bcc chronic lung infections gave rise to genotypic and phenotypic variation among isolates, contributing to their fitness while maintaining their capacity for survival in this opportunistic human niche
In inpatients with cirrhosis opioid use is common and associated with length of stay and persistent use post-discharge
Background Previous studies have demonstrated that opioids are often prescribed and associated with complications in outpatients with cirrhosis. Less is known about opioids among hospitalized patients with cirrhosis. We aimed to describe the patterns and complications of opioid use among inpatients with cirrhosis. Methods This retrospective cohort study included adult patients with cirrhosis admitted to a single hospital system from 4/4/2014 to 9/30/2015. We excluded hospitalizations with a surgery, invasive procedure, or palliative care/hospice consult in order to understand opioid use that may be avoidable. We determined the frequency, dosage, and type of opioids given during hospitalization. Using bivariable and multivariable analyses, we assessed length of stay, intensive care unit transfer, and in-hospital mortality by opioid use. Results Of 217 inpatients with cirrhosis, 118 (54.4%) received opioids during hospitalization, including 41.7% of patients without prior outpatient opioid prescriptions. Benzodiazepines or hypnotic sleep aids were given to 28.8% of opioid recipients. In the multivariable model, younger age and outpatient opioid prescription were associated with inpatient opioids. Hospitalization was longer among opioid recipients (median 3.9 vs 3.0 days, p = 0.002) and this difference remained after adjusting for age, cirrhosis severity, and medical comorbidities. There was no difference in intensive care unit transfers and no deaths occurred. At discharge, 22 patients were newly started on opioids of whom 10 (45.5%) had opioid prescriptions at 90 days post-discharge. Conclusion In non-surgical inpatients with cirrhosis, opioid prescribing was common and associated with prolonged length of stay. A high proportion of patients newly discharged with opioid prescriptions had ongoing prescriptions at 90 days post-discharge
Implementation of an Optimal First-Order Method for Strongly Convex Total Variation Regularization
We present a practical implementation of an optimal first-order method, due
to Nesterov, for large-scale total variation regularization in tomographic
reconstruction, image deblurring, etc. The algorithm applies to -strongly
convex objective functions with -Lipschitz continuous gradient. In the
framework of Nesterov both and are assumed known -- an assumption
that is seldom satisfied in practice. We propose to incorporate mechanisms to
estimate locally sufficient and during the iterations. The mechanisms
also allow for the application to non-strongly convex functions. We discuss the
iteration complexity of several first-order methods, including the proposed
algorithm, and we use a 3D tomography problem to compare the performance of
these methods. The results show that for ill-conditioned problems solved to
high accuracy, the proposed method significantly outperforms state-of-the-art
first-order methods, as also suggested by theoretical results.Comment: 23 pages, 4 figure
The anomaly line bundle of the self-dual field theory
In this work, we determine explicitly the anomaly line bundle of the abelian
self-dual field theory over the space of metrics modulo diffeomorphisms,
including its torsion part. Inspired by the work of Belov and Moore, we propose
a non-covariant action principle for a pair of Euclidean self-dual fields on a
generic oriented Riemannian manifold. The corresponding path integral allows to
study the global properties of the partition function over the space of metrics
modulo diffeomorphisms. We show that the anomaly bundle for a pair of self-dual
fields differs from the determinant bundle of the Dirac operator coupled to
chiral spinors by a flat bundle that is not trivial if the underlying manifold
has middle-degree cohomology, and whose holonomies are determined explicitly.
We briefly sketch the relevance of this result for the computation of the
global gravitational anomaly of the self-dual field theory, that will appear in
another paper.Comment: 41 pages. v2: A few typos corrected. Version accepted for publication
in CM
de Sitter Vacua in String Theory
We outline the construction of metastable de Sitter vacua of type IIB string
theory. Our starting point is highly warped IIB compactifications with
nontrivial NS and RR three-form fluxes. By incorporating known corrections to
the superpotential from Euclidean D-brane instantons or gaugino condensation,
one can make models with all moduli fixed, yielding a supersymmetric AdS
vacuum. Inclusion of a small number of anti-D3 branes in the resulting warped
geometry allows one to uplift the AdS minimum and make it a metastable de
Sitter ground state. The lifetime of our metastable de Sitter vacua is much
greater than the cosmological timescale of 10^10 years. We also prove, under
certain conditions, that the lifetime of dS space in string theory will always
be shorter than the recurrence time.Comment: 12 pages, 2 figs, added comments on the thin wall approximation to
tunnelin
Evidence of Final-State Suppression of High-p_T Hadrons in Au + Au Collisions Using d + Au Measurements at RHIC
Transverse momentum spectra of charged hadrons with 6 GeV/c have
been measured near mid-rapidity (0.2 1.4) by the PHOBOS experiment
at RHIC in Au + Au and d + Au collisions at . The spectra for different collision centralities are compared to collisions at the same energy. The resulting nuclear modification
factor for central Au + Au collisions shows evidence of strong suppression of
charged hadrons in the high- region ( GeV/c). In contrast, the d +
Au nuclear modification factor exhibits no suppression of the high-
yields. These measurements suggest a large energy loss of the high-
particles in the highly interacting medium created in the central Au + Au
collisions. The lack of suppression in d + Au collisions suggests that it is
unlikely that initial state effects can explain the suppression in the central
Au + Au collisions.Comment: 3 pages, 4 figures, International Europhysics Conference on High
Energy Physics EPS (July 17th-23rd 2003) in Aachen, German
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