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1.
Anaesthesist ; 68(10): 683-688, 2019 10.
Artigo em Alemão | MEDLINE | ID: mdl-31420706

RESUMO

This article reports the course of a complicated malaria in a 41-year-old male patient. After spending several months in Mali, the patient decompensated shortly after onset of the first symptoms. Under the signs of a multi-organ failure and with an initial parasitic load of 25%, the patient developed a microcirculation disturbance in the acra. In addition to sepsis-induced disseminated microthrombosis, high-dose catecholamine treatment contributes to the genesis of this disease with a high clinical probability. To improve the peripheral blood circulation, intravenous treatment with the synthetic prostaglandin E1 (PGE1) alprostadil with 20 µg (1-0-1) was carried out over a period of 21 days. Relevant circulatory depression as a side effect did not occur. The microcirculatory disturbances were no longer evident and the necrosis healed. Furthermore, the clearance course of the plasmodia was delayed under artemisinin-based combination therapy. Prolonged hemolysis required multiple transfusions.


Assuntos
Alprostadil/uso terapêutico , Malária Falciparum/complicações , Microcirculação/efeitos dos fármacos , Administração Intravenosa , Adulto , Artemisininas/uso terapêutico , Humanos , Masculino
2.
Astrophys J ; 871(2)2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32831351

RESUMO

Emission from Saggitarius A* is highly variable at both X-ray and infrared (IR) wavelengths. Observations over the last ~20 yr have revealed X-ray flares that rise above a quiescent thermal background about once per day, while faint X-ray flares from Sgr A* are undetectable below the constant thermal emission. In contrast, the IR emission of Sgr A* is observed to be continuously variable. Recently, simultaneous observations have indicated a rise in IR flux density around the same time as every distinct X-ray flare, while the opposite is not always true (peaks in the IR emission may not be coincident with an X-ray flare). Characterizing the behavior of these simultaneous X-ray/IR events and measuring any time lag between them can constrain models of Sgr A*'s accretion flow and the flare emission mechanism. Using 100+ hours of data from a coordinated campaign between the Spitzer Space Telescope and the Chandra X-ray Observatory, we present results of the longest simultaneous IR and X-ray observations of Sgr A* taken to date. The cross-correlation between the IR and X-ray light curves in this unprecedented data set, which includes four modest X-ray/IR flares, indicates that flaring in the X-ray may lead the IR by approximately 10-20 min with 68% confidence. However, the 99.7% confidence interval on the time-lag also includes zero, i.e., the flaring remains statistically consistent with simultaneity. Long-duration and simultaneous multi-wavelength observations of additional bright flares will improve our ability to constrain the flare timing characteristics and emission mechanisms, and must be a priority for Galactic Center observing campaigns.

3.
Mon Not R Astron Soc ; 459(3): 2681-2689, 2016 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27279782

RESUMO

The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks - six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν-0.4), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes.

4.
Science ; 341(6149): 981-3, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-23990554

RESUMO

Most supermassive black holes (SMBHs) are accreting at very low levels and are difficult to distinguish from the galaxy centers where they reside. Our own Galaxy's SMBH provides an instructive exception, and we present a close-up view of its quiescent x-ray emission based on 3 megaseconds of Chandra observations. Although the x-ray emission is elongated and aligns well with a surrounding disk of massive stars, we can rule out a concentration of low-mass coronally active stars as the origin of the emission on the basis of the lack of predicted iron (Fe) Kα emission. The extremely weak hydrogen (H)-like Fe Kα line further suggests the presence of an outflow from the accretion flow onto the SMBH. These results provide important constraints for models of the prevalent radiatively inefficient accretion state.

5.
Nature ; 455(7212): 506-9, 2008 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-18818652

RESUMO

Magnetars are young neutron stars with very strong magnetic fields of the order of 10(14)-10(15) G. They are detected in our Galaxy either as soft gamma-ray repeaters or anomalous X-ray pulsars. Soft gamma-ray repeaters are a rare type of gamma-ray transient sources that are occasionally detected as bursters in the high-energy sky. No optical counterpart to the gamma-ray flares or the quiescent source has yet been identified. Here we report multi-wavelength observations of a puzzling source, SWIFT J195509+261406. We detected more than 40 flaring episodes in the optical band over a time span of three days, and a faint infrared flare 11 days later, after which the source returned to quiescence. Our radio observations confirm a Galactic nature and establish a lower distance limit of approximately 3.7 kpc. We suggest that SWIFT J195509+261406 could be an isolated magnetar whose bursting activity has been detected at optical wavelengths, and for which the long-term X-ray emission is short-lived. In this case, a new manifestation of magnetar activity has been recorded and we can consider SWIFT J195509+261406 to be a link between the 'persistent' soft gamma-ray repeaters/anomalous X-ray pulsars and dim isolated neutron stars.

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