1,301 research outputs found
High incidence of Angina pectoris in patients treated with 5-fluorouracil - A planned surveillance study with 102 patients
Objective: Angina pectoris, arrhythmic sudden death and myocardial infarction, all these cardiac events have occasionally been reported during 5-fluorouracil (5-FU) chemotherapy. Underlying mechanisms leading to these events are unknown; damage to the myocytes or vasospasms have been discussed. Methods: 102 consecutive and unselected patients were monitored with 12-lead ECG, echocardiography and radionuclide ventriculography prior to the first cycle of 5-FU chemotherapy and 3 months from baseline. Results: 19% of the patients developed reversible symptoms of angina pectoris during treatment which lasted up to 12 h after cessation of the infusion. Most of the 19 patients showed corresponding ECG changes. 6 out of the 19 patients with severe angina pectoris had subsequent coronary angiography. In none of these patients the coronary angiography showed coronary artery disease, but it showed low ventricular function (ejection fraction <50%) in 2 patients. The ejection fraction did not increase overtime. Arrhythmias were screened for with Holter monitoring during 5-FU chemotherapy. The frequency of bradycardia and ventricular extrasystoles increased significantly (p < 0.05) during treatment compared to arrhythmias in Holter monitoring 3 months later. Furthermore the Qtc time in the ECG 3 months later was significantly prolonged (p < 0.05) compared to baseline values. Conclusions:The incidence of angina pectoris in patients during 5-FU treatment seems higher than previously suspected. As myocardial ischemia can be fatal, attentiveness to these symptoms and immediate treatment are crucial. Copyright (C) 2003 S. Karger AG, Basel
Fermi surface instabilities in CeRh2Si2 at high magnetic field and pressure
We present thermoelectric power (TEP) studies under pressure and high
magnetic field in the antiferromagnet CeRh2Si2 at low temperature. Under
magnetic field, large quantum oscillations are observed in the TEP, S(H), in
the antiferromagnetic phase. They suddenly disappear when entering in the
polarized paramagnetic (PPM) state at Hc pointing out an important
reconstruction of the Fermi surface (FS). Under pressure, S/T increases
strongly of at low temperature near the critical pressure Pc, where the AF
order is suppressed, implying the interplay of a FS change and low energy
excitations driven by spin and valence fluctuations. The difference between the
TEP signal in the PPM state above Hc and in the paramagnetic state (PM) above
Pc can be explained by different FS. Band structure calculations at P = 0
stress that in the AF phase the 4f contribution at the Fermi level (EF) is weak
while it is the main contribution in the PM domain. By analogy to previous work
on CeRu2Si2, in the PPM phase of CeRh2Si2 the 4f contribution at EF will drop.Comment: 10 pages, 13 figure
WSPC- Proceedings Trim Size: 9in x 6in main 1 Characterizing Swing-Leg Retraction in Human Locomotion
contact, is observed in human locomotion. While several advantages of swingleg retraction, like gait stability and perturbation rejection, are shown by conceptual models, there is currently very little experimental data on swing-leg retraction in human motion. In this paper, kinematic data for twenty-eight subjects walking and running at different speeds are analyzed. Swing-leg retraction was shown to exist in walking and running at every non-zero speed. Additionally, swing-leg retraction speed and acceleration linearly increase with gait speed. At comparable gait speeds, swing-leg retraction speed is higher for running than for walking
Perceptually Motivated Wavelet Packet Transform for Bioacoustic Signal Enhancement
A significant and often unavoidable problem in bioacoustic signal processing is the presence of background noise due to an adverse recording environment. This paper proposes a new bioacoustic signal enhancement technique which can be used on a wide range of species. The technique is based on a perceptually scaled wavelet packet decomposition using a species-specific Greenwood scale function. Spectral estimation techniques, similar to those used for human speech enhancement, are used for estimation of clean signal wavelet coefficients under an additive noise model. The new approach is compared to several other techniques, including basic bandpass filtering as well as classical speech enhancement methods such as spectral subtraction, Wiener filtering, and Ephraim–Malah filtering. Vocalizations recorded from several species are used for evaluation, including the ortolan bunting (Emberiza hortulana), rhesus monkey (Macaca mulatta), and humpback whale (Megaptera novaeanglia), with both additive white Gaussian noise and environment recording noise added across a range of signal-to-noise ratios (SNRs). Results, measured by both SNR and segmental SNR of the enhanced wave forms, indicate that the proposed method outperforms other approaches for a wide range of noise conditions
Superconducting phase diagram of the filled skuterrudite PrOs4Sb12
We present new measurements of the specific heat of the heavy fermion
superconductor PrOs4Sb12, on a sample which exhibits two sharp distinct
anomalies at Tc1= 1.89K and Tc2= 1.72K. They are used to draw a precise
magnetic field-temperature superconducting phase diagram of PrOs4Sb12 down to
350 mK.
We discuss the superconducting phase diagram of PrOs4Sb12 and its possible
relation with an unconventional superconducting order parameter. We give a
detailed analysis of Hc2(T), which shows paramagnetic limitation (a support for
even parity pairing) and multiband effects
Multiband superconductivity in the heavy fermion compound PrOs4Sb12
The thermal conductivity of the heavy fermion superconductor PrOs4Sb12 was
measured down to Tc/40 throughout the vortex state. At lowest temperatures and
for magnetic fields H ~ 0.07Hc2, already 40% of the normal state thermal
conductivity is restored. This behaviour (similar to that observed in MgB2) is
a clear signature of multiband superconductivity in this compound.Comment: 12pages, version #1 20\_06\_200
Fermi-surface topology of the iron pnictide LaFeP
We report on a comprehensive de Haas--van Alphen (dHvA) study of the iron
pnictide LaFeP. Our extensive density-functional band-structure
calculations can well explain the measured angular-dependent dHvA frequencies.
As salient feature, we observe only one quasi-two-dimensional Fermi-surface
sheet, i.e., a hole-like Fermi-surface cylinder around , essential for
pairing, is missing. In spite of considerable mass enhancements due to
many-body effects, LaFeP shows no superconductivity. This is likely
caused by the absence of any nesting between electron and hole bands.Comment: 5 pages, 4 figure
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