644 research outputs found
Subdiffusive transport in intergranular lanes on the Sun. The Leighton model revisited
In this paper we consider a random motion of magnetic bright points (MBP)
associated with magnetic fields at the solar photosphere. The MBP transport in
the short time range [0-20 minutes] has a subdiffusive character as the
magnetic flux tends to accumulate at sinks of the flow field. Such a behavior
can be rigorously described in the framework of a continuous time random walk
leading to the fractional Fokker-Planck dynamics. This formalism, applied for
the analysis of the solar subdiffusion of magnetic fields, generalizes the
Leighton's model.Comment: 7 page
Combined In Silico, In Vivo, and In Vitro Studies Shed Insights into the Acute Inflammatory Response in Middle-Aged Mice
We combined in silico, in vivo, and in vitro studies to gain insights into age-dependent changes in acute inflammation in response to bacterial endotoxin (LPS). Time-course cytokine, chemokine, and NO2-/NO3- data from "middle-aged" (6-8 months old) C57BL/6 mice were used to re-parameterize a mechanistic mathematical model of acute inflammation originally calibrated for "young" (2-3 months old) mice. These studies suggested that macrophages from middle-aged mice are more susceptible to cell death, as well as producing higher levels of pro-inflammatory cytokines, vs. macrophages from young mice. In support of the in silico-derived hypotheses, resident peritoneal cells from endotoxemic middle-aged mice exhibited reduced viability and produced elevated levels of TNF-α, IL-6, IL-10, and KC/CXCL1 as compared to cells from young mice. Our studies demonstrate the utility of a combined in silico, in vivo, and in vitro approach to the study of acute inflammation in shock states, and suggest hypotheses with regard to the changes in the cytokine milieu that accompany aging. © 2013 Namas et al
Hybridization in parasites: consequences for adaptive evolution, pathogenesis and public health in a changing world
[No abstract available
Surgical Management for Advanced Heart Failure in Adults with Congenital Heart Disease
Adults with congenital heart disease (ACHD) have emerged as a new patient population that poses a variety of treatment and management obstacles. This chapter discusses the diagnosis of heart failure and treatment challenges faced by ACHD specifically addressing when to initiate mechanical circulatory support versus heart transplantation. It is evident that the ACHD population presents with a variety of unique challenges and considerations that still need to be explored. Addressing each of these issues will vastly change and improve how ACHD patients are approached from a treatment standpoint and ultimately provide more advantageous clinical options that can successfully handle the complexities presented by this population
Stochastic resetting by a random amplitude
Stochastic resetting, a diffusive process whose amplitude is reset to the origin at random times, is a vividly studied strategy to optimize encounter dynamics, e.g., in chemical reactions. Here we generalize the resetting step by introducing a random resetting amplitude such that the diffusing particle may be only partially reset towards the trajectory origin or even overshoot the origin in a resetting step. We introduce different scenarios for the random-amplitude stochastic resetting process and discuss the resulting dynamics. Direct applications are geophysical layering (stratigraphy) and population dynamics or financial markets, as well as generic search processes.Predoc Severo Ochoa 2018 grant PRE2018-084427;
DFG Grant No. ME 1535/12-
Management of severe tricuspid valve regurgitation due to ruptured papillary muscle in a patient with mediastinitis early after heart transplant
OBJECTIVE: Even though severe tricuspid regurgitation is not uncommon after cardiac transplantation, primary severe tricuspid regurgitation is rare. We present such a case with additional complexities.
METHODS: The patient was 44-year-old man with a HeartWare durable left ventricular assist device (Heartware Inc) who received a temporary right ventricular assist device (RVAD) with a ProtekDuo cannula (LivaNova Inc USA) for refractory ventricular fibrillation and underwent a heart transplant as United Network for Organ Sharing Status 1, in the presence of partially compensated cardiogenic shock, renal failure. Given complex re-operative surgery in a volume-overloaded patient with unknown pulmonary vascular resistance, an RVAD cannula was preserved and re- inserted during cardiac transplant. Postoperatively he required hemodialysis, had severe primary tricuspid regurgitation discovered after RVAD removal and developed Enterobacter mediastinitis. He underwent complex tricuspid valve repair for flail tricuspid leaflet due to ruptured papillary muscle likely due to RVAD cannula injury, after multiple mediastinal washouts and was followed by delayed chest reconstruction.
RESULTS: The patient is doing well, 6 months after discharge to home, asymptomatic, without re-admissions, on renal recovery path, with no tricuspid regurgitation and good biventricular function.
CONCLUSIONS: Replacing the tricuspid valve in presence of hemodialysis catheter, immunosuppression and mediastinitis could be high risk for endocarditis. Even though we have short-term follow-up, tricuspid valve repair can be an effective way of managing primary severe regurgitation especially when there is a desire or need to avoid valve replacement
Surgically implanted endovascular, microaxial left ventricular assist device: A single institution study
OBJECTIVE: The Impella 5.5 (Abiomed, Inc), a surgically implanted endovascular microaxial left ventricular assist device, is increasingly used worldwide and there have been more than 10,000 implants. The purpose of this study is to describe a large-volume, single-center experience with the use of the Impella 5.5.
METHODS: Data were obtained retrospectively from patients supported with the Impella 5.5 implanted at our institution from May 1, 2020, to December 31, 2022. Demographic, operative, and postoperative outcomes for each group are described. Results are reported in median (interquartile range) or n (%). The entire cohort was divided into 5 main groups based on the intention to treat at the time of the Impella 5.5 implantation: (1) patients who had a planned Impella 5.5 implanted at the time of high-risk cardiac surgery; (2) patients with cardiogenic shock; (3) patients bridged to a durable left ventricular assist device; (4) patients bridged to transplant; and (5) patients with postcardiotomy shock who received an unplanned Impella 5.5 implant.
RESULTS: A total of 126 patients were supported with the Impella 5.5. Overall survival to device explant was 76.2%, with 67.5% surviving to discharge. Midterm survival was assessed with a median follow-up time of 318 days and demonstrated an overall survival of 60.3% and a median of 650 days (549-752).
CONCLUSIONS: Outcomes after using the Impella 5.5 are variable depending on the indication of use. Patient selection may be of utmost importance and requires further experience with this device to determine who will benefit from insertion
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