Benign giant mediastinal schwannoma presenting as cardiac tamponade in a woman: a case report

<p>Abstract</p> <p>Introduction</p> <p>Mediastinal schwannomas are typically benign and asymptomatic, and generally present no immediate risks. We encountered a rare case of a giant benign posterior mediastinal schwannoma, complicated by life-threatening cardiac tamponade.</p> <p>Case presentation</p> <p>We report the case of a 72-year-old Japanese woman, who presented with cardiogenic shock. Computed tomography of the chest revealed a posterior mediastinal mass 150 cm in diameter, with pericardial effusion. The cardiac tamponade was treated with prompt pericardial fluid drainage. A biopsy was taken from the mass, and after histological examination, it was diagnosed as a benign schwannoma, a well-encapsulated non-infiltrating tumor, originating from the intrathoracic vagus nerve. It was successfully excised, restoring normal cardiac function.</p> <p>Conclusion</p> <p>Our case suggests that giant mediastinal schwannomas, although generally benign and asymptomatic, should be excised upon discovery to prevent the development of life-threatening cardiopulmonary complications.</p

Die Prüfung von Verlaufskurven auf das Vorliegen von Trends über die exakte Verteilung von Spearman's S

no abstract availabl

Fiber bursts as 3D coronal magnetic field probe in postflare loops

Fiber bursts appear in some complex solar radio bursts as a continuum fine structure in the frequency range of 150$\cdots$3000 MHz. We present and test a new method to use fiber bursts as a probe of the magnetic field strength and the 3D field structure in postflare loops. Thereby we assume that fiber bursts are driven by whistler waves ascending in the postflare loops which act as magnetic traps for nonthermal flare electrons. For a selected event (1997 April 07) we derive from dynamic radio spectra (Potsdam) and Nançay Radio Heliograph imaging data of fiber bursts the coronal magnetic field strength within the fiber burst source. We compare the fiber burst source positions and field strength estimates with the extrapolated potential magnetic field above the flaring active region NOAA 8027 using SOHO-MDI photospheric field data. The field strength from fiber bursts are within a factor of 0.6 to 1.4 of the field strength of the selected subset of potential field lines and give preference to a 3.5 times Newkirk (1961, ApJ, 133, 983) coronal density model within the evolving postflare loops. We find independent proof of the physical significance of considering selected potential field lines as postflare loop field information regarding topology and field strength over a time interval of one hour after the impulsive flare phase. We conclude that radio decimeter and meter wave spectra and radio imaging at two representative frequencies are sufficient for a reliable estimate of the (otherwise not measurable) coronal magnetic field strength in postflare loops. This can be an important field sounding method using the forthcoming FASR (Frequency Agile Solar Radiotelescope) instrument

A microflare with hard X-ray-correlated gyroresonance line emission at 314 MHz

Context. Small energy release events in the solar corona can give insights into the flare process which are regularly hidden in the complex morphology of larger events. For one case we find a narrowband radio signal well correlated with the hard X-ray flare. We investigate wether these signals are probes for the flare current sheet. Aims. We aim to establish the relation between narrowband and short-duration features (<1% of the observing frequency in the spectral range 250–340 MHz, and some 5 s until 2  min, respectively) in dynamic radio spectral diagrams and simultaneously occuring HXR bursts. Methods. We use dynamic radio spectra from the Astrophysical Institute Potsdam, HXR images of RHESSI, TRACE coronal and chromospheric images, SOHO-MDI high resolution magnetogram data, and its potential field extrapolation for the analysis of one small flare event in AR10465 on September 26, 2003. We point to similar effects in e.g. the X-class flare on November 03, 2003 to demonstrate that we are not dealing with a singular phenomenon. Results. We confirm the solar origin of the extremely narrowband radio emission. From RHESSI images and the magnetic field data we identify the probable site of the radio source as well as the HXR footpoint and the SXR flare loop emission. The flare loop is included in an ongoing change of magnetic connectivity as confirmed by TRACE images of hot coronal loops. The flare energy is stored in the nonpotential magnetic field substructure around the microflare site which is relaxed to a potential one. Conclusions. We conclude that the correlated HXR footpoint/narrowband radio emission, and the transition to a second energy release in HXR without associated radio emission are direct probes of changing magnetic connectivity during the flare. We suppose that the narrowband radio emission is due to gyroresonance radiation at the second harmonic of the local electron cyclotron frequency. It follows an upper limit of the magnetic field in the radio source volume of less than 50% of the mean potential field in the same height range. This supports the idea that the narrowband radio source is situated in the immediate surroundings of the flare current sheet

The GLE on Oct. 28, 2003 – radio diagnostics of relativistic electron and proton injection

Timing discrepancies between signatures of accelerated particles at the sun and the arrival times of the particles at near-earth detectors are a matter of fundamental interest for space-weather applications. The solar injection times of various components of energetic particles were derived by Klassen et al. (2005, JGR, 110, A09S04) for the October 28, 2003, X-class/γ-ray flare in NOAA AR 10486. This flare occured in connection with a fast halo coronal mass ejection and a neutron monitor-observed ground level event (GLE). We used radio (Astrophysikalisches Institut Potsdam, \emph{WIND}, Nançay Multifrequency Radio Heliograph), Hα (Observatorium Kanzelhöhe), \emph{RHESSI}, \emph{SOHO} (EIT, LASCO, MDI), and \emph{TRACE} data to study the associated chromospheric and low coronal phenomena. We identify three source sites of accelerated particles in this event. Firstly, there is a source in projection 0.3 $R_\odot$ away from AR 10486, which is the site of the reconnection outflow termination, as revealed by a termination shock signature in the dynamic radio spectrum. Secondly, there is the extended current sheet above a giant coronal postflare loop system in the main flare phase. Thirdly, there is a source situated on a magnetic separatrix surface between several magnetic arcades and neighbouring active regions. This source is 0.2 $R_\odot$ away from AR 10486 and acts during onset and growth of high energy proton injection in space. It is not clear if this source is related to the acceleration of protons, or if it only confirms that energetic particles penetrate a multistructure magnetic loop system after being previously accelerated near the main HXR- and γ-ray sources. The result is in favour of energetic particle acceleration in the low corona (<0.5 $R_\odot$ above the photosphere) and in contrast to acceleration of the relativistic particles at remotely propagating shock waves.

Auswertung von Verlaufsdaten: Anwendungsorientierte Darstellung anhand von Beispielen aus Pharmakologie und Psychiatrie

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Modified Case Method for Piles with Section Step Changes

Applied during pile driving, the Case Method offers an immediate estimate of the static resistance to driving (SRD) after each hammer blow. It has been used in its original form both in the onshore and offshore piling industry for more than 40 years to provide an indication of the pile static capacity. The Case Method requires measurements of force and velocity near the pile head as the hammer strikes the pile and produces an analytical estimate of the SRD, using a number of assumptions. One of them requires the pile to be of constant impedance (or cross section) along its length. However, for reason of economy, driven piles are often composed of several sections of different cross sections. The Case Method provides in that case an inaccurate estimate of the SRD. This article presents an improved version of the original Case Method which takes into account possible variations of impedance along the pile. A numerical validation shows that for piles displaying impedance changes, the modified Case Method presented herein provides an estimate closer to the actual SRD than the original Case Method. That conclusion is further validated by applying the modified Method to pile driving records and comparing its results to SRD estimates obtained through more reliable modelling