Search results for "Transient"
showing 10 items of 623 documents
Transient guided-mode resonance metasurfaces with phase-transition materials
2023
We investigate transient, photo-thermally induced metasurface effects in a planar thin-film multilayer based on a phase-transition material. Illumination of a properly designed multilayer with two obliquely incident and phase-coherent pulsed pumps induces a transient and reversible temperature pattern in the phase-transition layer. The deep periodic modulation of the refractive index, caused by the interfering pumps, produces a transient Fano-like spectral feature associated with a guided-mode resonance. A coupled opto-thermal model is employed to analyze the temporal dynamics of the transient metasurface and to evaluate its speed and modulation capabilities. Using near-infrared pump pulses…
Protein Adsorption Hysteresis and Transient States of Fibrinogen and BMP-2 as Model Mechanisms for Proteome-Binding to Implants
2020
Abstract Protein adsorption studies returned to the focus of medical therapeutics, when it was found that up to 2500 non-plasma proteins adsorbed to hip implants during arthroplastic surgery, challenging peri-implant healing models. Questions have re-emerged as to the implications of uncontrolled protein unfolding after adsorption. In past studies on the cooperativity of protein binding we discovered protein adsorption hysteresis, a thermodynamically irreversible process. The present precursory study comprises real-time kinetic (TIRF-Rheometry) and equilibrium (125I-tracer ) studies on the hysteretic binding of fibrinogen and rhBMP-2 to titanium and glass surfaces via transient states. Ther…
The Lorenz system : hidden boundary of practical stability and the Lyapunov dimension
2020
On the example of the famous Lorenz system, the difficulties and opportunities of reliable numerical analysis of chaotic dynamical systems are discussed in this article. For the Lorenz system, the boundaries of global stability are estimated and the difficulties of numerically studying the birth of self-excited and hidden attractors, caused by the loss of global stability, are discussed. The problem of reliable numerical computation of the finite-time Lyapunov dimension along the trajectories over large time intervals is discussed. Estimating the Lyapunov dimension of attractors via the Pyragas time-delayed feedback control technique and the Leonov method is demonstrated. Taking into accoun…
Fast Photochemistry of Prototypical Phytochromes : A Species vs. Subunit Specific Comparison
2015
Phytochromes are multi-domain red light photosensor proteins, which convert red light photons to biological activity utilizing the multitude of structural and chemical reactions. The steady increase in structural information obtained from various bacteriophytochromes has increased understanding about the functional mechanism of the photochemical processes of the phytochromes. Furthermore, a number of spectroscopic studies have revealed kinetic information about the light-induced reactions. The spectroscopic changes are, however, challenging to connect with the structural changes of the chromophore and the protein environment, as the excited state properties of the chromophores are very sens…
Dubái: estrategias para una posible transición urbana
2020
The article presents the work "Dubai Pop-Up. Architecture in a transient city", the result of an international design workshop (coordinated by T. Aglieri Rinella and R. Garcia Rubio) which brought the Dubai question to the center, bringing together a large number of teachers and students to think how to introduce new ways of thinking about the city. Thanks to the diversified and sometimes surprising hypotheses that the projects developed suggest, it is clear how open the degree of alternatives to that development model only oriented on the “monoculture of profit” that has guided urban choices in this city up to now can still be.
Impairment of the modulatory role of nitric oxide on the endothelin-1-elicited contraction of cerebral arteries: a pathogenetic factor in cerebral va…
1997
OBJECTIVE: Nitric oxide (NO) and endothelin-1 (ET-1) are two endothelium-derived factors probably involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). Our aim was twofold, i.e., to ascertain whether endothelial and nonendothelial NO modulates the contractile response of cerebral arteries to ET-1 and to analyze whether this relationship might be impaired after experimental SAH. METHODS: Rings of middle cerebral artery from goats in the control group and from goats with SAH were set up for isometric tension recordings. SAH was induced 3 days before the experiments by infusion of 10 ml of autologous arterial blood through a catheter previously inserted into t…
Transient focal cerebral ischemia significantly alters not only EAATs but also VGLUTs expression in rats: relevance of changes in reactive astroglia
2010
The involvement of plasma membrane glutamate transporters (EAATs - excitatory aminoacid transporters) in the pathophysiology of ischemia has been widely studied, but little is known about the role of vesicular glutamate transporters (VGLUTs) in the ischemic process. We analyzed the expression of VGLUT1-3 in the cortex and caudate-putamen of rats subjected to transient middle cerebral artery occlusion. Western blot and immunohistochemistry revealed an increase of VGLUT1 signal in cortex and caudate-putamen until 3 days of reperfusion followed by a reduction 7 days after the ischemic insult. By contrast, VGLUT2 and 3 were drastically reduced. Confocal microscopy revealed an increase in VGLUT2…
Chronic hepatitis C in children is a mild and curable liver disease
2011
Hepatitis C virus (HCV) infection is a major health problem orldwide, but children constitute only a small portion of infected atients. HCV transmission can occur through blood transfusion, nd the incidence of HCV infection was very high in children transused before 1990 for treatment of chronic haematological diseases 1] or other diseases that required blood transfusion [2]. Since he introduction of screening for HCV infection, blood transfusions ave become safe in developed countries, and the residual risk is oday very limited. In developed countries, maternal–fetal transmission has ecome themajor risk factor for HCV in children,with an estimated isk of infection ranging from 2% to 6% [3]…
Predictors of advanced fibrosis in non-cirrhotic non-alcoholic fatty liver disease in Germany
2018
BACKGROUND Advanced fibrosis has been established as the most important predictor of overall mortality in patients with non-alcoholic fatty liver disease (NAFLD). In contrast to cirrhosis, advanced, non-cirrhotic NAFLD is difficult to identify and data from Germany are lacking. AIM To identify clinical factors associated with advanced, non-cirrhotic fibrosis. METHODS Patients were recruited in the prospectively enrolling European NAFLD Registry. Clinical characteristics and the performance of non-invasive surrogate scores compared with vibration-controlled transient elastography are reported. RESULTS Two hundred and sixty-one patients with non-cirrhotic NAFLD on liver biopsy (mean age 51 ye…
Are non-invasive fibrosis markers for chronic hepatitis B reliable in sub-Saharan Africa?
2017
Background In the absence of liver biopsy, the World Health Organization recommends non-invasive tests, such as aspartate aminotransferase to platelet ratio index and FIB-4, to assess liver fibrosis in patients with chronic hepatitis B. However, these tests are not well validated in sub-Saharan Africa. Recently, a new marker, gamma-glutamyl transpeptidase to platelet ratio, was found to be more accurate in an African setting, but this needs confirmation in other cohorts. Methods A treatment program for chronic hepatitis B was initiated in Addis Ababa, Ethiopia, in 2015. Non-invasive tests were compared with transient elastography (Fibroscan 402, Echosense, France) using the following thresh…