10 research outputs found
Draping of Cluster Magnetic Fields over Bullets and Bubbles -- Morphology and Dynamic Effects
High-resolution X-ray observations have revealed cavities and `cold fronts'
with sharp edges in temperature, density, and metallicity within galaxy
clusters. Their presence poses a puzzle since these features are not expected
to be hydrodynamically stable, or to remain sharp in the presence of diffusion.
However, a moving core or bubble in even a very weakly magnetized plasma
necessarily sweeps up enough magnetic field to build up a dynamically important
sheath around the object; the layer's strength is set by a competition between
`plowing up' of field and field lines slipping around the core. We show that a
two-dimensional approach to the problem is quite generally not possible. In
three dimensions, we show with analytic arguments and in numerical experiments,
that this magnetic layer modifies the dynamics of a plunging core, greatly
modifies the effects of hydrodynamic instabilities on the core, modifies the
geometry of stripped material, and even slows the fall of the core through
magnetic tension. We derive an expression for the maximum magnetic field
strength, the thickness of the layer, and the opening angle of the magnetic
wake. The morphology of the magnetic draping layer implies the suppression of
thermal conduction across the layer, thus conserving strong temperature
gradients over the contact surface. The intermittent amplification of the
magnetic field as well as the injection of MHD turbulence in the wake of the
core is identified to be due to vorticity generation within the magnetic
draping layer. These results have important consequences for understanding the
physical properties and the complex gasdynamical processes of the intra-cluster
medium, and apply quite generally to motions through other magnetized
environments, e.g., the ISM.Comment: For version of this paper with interactive 3D graphics and
full-resolution figures, see http://www.cita.utoronto.ca/~ljdursi/draping/ .
19p, 26 figures, emulateapj format. Version accepted by ApJ - new references,
improved figure
Kidneys functional state in patients suffered purulent pyelonephritis
Introduction. Purulent pyelonephritis is a complicated urinary tract infection with one of the most severe currents. It represents a serious clinical problem associated with the complexity of the choice of diagnosis and the optimal active treatment strategy, as well as the need for subsequent rehabilitation of this category of patients.Purpose of the study. Studying of the immediate and remote results of the kidneys` functional state in patients who have undergone purulent pyelonephritis using a differentiated approach to treatment tactics.Materials and methods. The study included 84 patients who underwent purulent pyelonephritis at the age of 15 to 70 years old and were treated at the Botkin City Clinical Hospital from 1999 to 2007. The patients were divided into three groups depending on the method of treatment: group 1 - open surgery of 18 patients (21.4%); group 2 - percutaneous drainage methods - 38 (45.3%); group 3 - conservative therapy - 28 (33.3%) patients. Examination of patients included dynamic nephroscintigraphy and complex ultrasound. It was performed in time after treatment after 12, 36 and 60, 84 months.Results. During the 7-year observation of patients, it was found that a more pronounced renal dysfunction and perfusion occurred during all periods of observation after undergoing open surgery according to Doppler sonography. Restoration of renal function occurred in shorter observation periods after the use of percutaneous kidney drainage and conservative treatment.Conclusion. Based on the data obtained, it can be concluded that a differentiated approach to the choice of tactics for the treatment of patients with purulent pyelonephritis is reasonable. Accordingly, it should be introduced into clinical practice of urological departments that provide emergency care to urological patients
How Frequently Does out-of Hospital Sudden Unexpected Infants Death Represent the Sudden Infant Death Syndrome?
Background. 19.6 % of all fatal cases among Russian children who died in the first year of life are registered out-of hospital, and they are usually sudden. Out-of-hospital sudden unexpected infant death (OSUID) could be confused with sudden infant death syndrome (SIDS) followed by the wide variation in the diagnostic indicators of the syndrome.The aim of the study is to reveal the pathological changes in the tissues and organs of 420 cases of OSUID (group 1) compared with 350 cases of death in the hospital (group 2), to estimate the conformity of the final diagnoses and to identify cases of OSUID, which were SIDS.Methods. From 2009 to 2016 pathoanatomical and virological study of the organs of 420 cases of OSUID (group 1) and 350 babies who died in a hospital were carried out.Results. It was established that the age of infants of the 1st group at the time of death in 71 % of cases corresponded to the age of SIDS. In terms of gestational age and body weight at birth babies of the 1st group turned out to be much more prosperous. Signs of rapid onset of death in this group: plethora of internal organs (83.3 %) and petechial hemorrhages (75.5 %) were present significantly more often than in the 2nd. In the 1st group, predominantly light acute respiratory viral infections (ARVI) with minimal pathologic signs and pneumonia were diagnosed, but pneumonia in 33.3 % not detected at autopsy. Purulent tracheobronchitis (0 and 21.4 %), bacterial pneumonia (6.3 and 26.3 %), a large area of lung damage (3.8 and 56.1 %) were detected much less frequently in the 1st group. In 38 % of the 1st group, pneumonia was the only cause of death, and in no case in the 2nd. Pathology of the cardiovascular system (55.2 and 87.7 %), central nervous system (58.6 and 90.9 %);urogenital system (34.8 and 62.9), inflammation of the membranes and brain tissue (21.9 and 70.0 %), signs of past or current intrauterine viral infection (29.5 and 64.0 %) in the 1st group was diagnosed much less frequently than in the 2nd, but congenital syphilis, HIV infection and hepatitis C — 3 times more often (12.9 and 3.7 %). The more frequent pathology of the adrenal glands in the 1st group (66.7 and 34 %) could cause inadequate responses to minimal exposure to external factors, including mild acute respiratory viral infections. The diagnosis of SIDS was made in 3 cases and in 3 more it was questionable. However, the presence of multisystemic pathology excludes the diagnosis of SIDS. The diagnosis of SIDS could be established in 30 cases in cases of slight ARVI without intoxication, shock liver or disseminated intravascular coagulation syndrome.Conclusion. The most cases of sudden death occurred in not obvious life-threatening conditions in socially disadvantaged families in the absence of adequate observation, diagnosis and treatment