Search results for "Reactivity"
showing 10 items of 880 documents
In vitro tracheal hyperresponsiveness to muscarinic receptor stimulation by carbachol in a rat model of bleomycin-induced pulmonary fibrosis
2006
Summary 1 Bleomycin-induced lung injury is widely used as an experimental model to investigate the pathophysiology of pulmonary fibrosis but the alterations in the pharmacological responsiveness of airways isolated from bleomycin-exposed animals has been scarcely investigated. The aim of this study was to examine the in vitro tracheal responses to muscarinic receptor stimulation with carbachol in a rat bleomycin model. 2 Concentration–response curves to carbachol (10 nm to 0.1 mm) were obtained in tracheal rings isolated from Sprague–Dawley rats 14 days after endotracheal bleomycin or saline. The intracellular calcium signal in response to carbachol (10 μm) was measured by epifluorescence m…
How are neuroticism and depression related to the psychophysiological stress response to acute stress in healthy older people?
2015
Neuroticism and depressive symptomatology have been related to a heightened and diminished physiological stress response, which may partly explain their negative relationship with health and wellbeing. Identifying factors that may increase disease vulnerability is especially relevant in older people, whose physiological systems decline. With this in mind, we investigated the influence of neuroticism and depression on the psychophysiological stress response in healthy older people (from 55 to 76years old). A total of 36 volunteers were exposed to a stressful task (Trier Social Stress Test, TSST), while 35 volunteers performed a control non-stressful task. The physiological stress response wa…
Acute intermittent nicotine treatment produces a reduction in the total number of FGF-2 immunoreactive astroglial cells in the substantia nigra of th…
2004
To understand the morphological substrate of the nicotine effect on nigral FGF-2 expression, a stereological analysis of FGF-2 immunoreactive neuronal and glial profiles has been performed in the substantia nigra of the rat after acute intermittent nicotine treatment. The major finding of this paper is the demonstration that this type of nicotine treatment produces a significant reduction in the total number of nuclear FGF-2 immunoreactive astroglial profiles in the substantia nigra. A parallel analysis of nigral FGF-1 and FGF-5 immunoreactivities showed no effect of this type of nicotine treatment. The results may be explained by an inhibition of FGF-2 synthesis in a subpopulation of nigra…
Increased responsiveness of human pulmonary arteries in patients with positive bronchodilator response.
1996
Abstract 1. The effects of noradrenaline, endothelin-1, acetylcholine and sodium nitroprusside were studied in isolated pulmonary arteries obtained from 14 patients undergoing lobectomy for lung carcinoma. Seven patients had shown increased response to a bronchodilator test prior to operation. In the remaining patients (control) the bronchodilator test was negative. 2. Artery rings from patients with a positive bronchodilator response showed greater contraction to noradrenaline (pD2 = 6.44 +/- 0.1; Emax = 93 +/- 9% of response to 100 mM KCl) and endothelin-1 (pD2 = 8.92 +/- 0.1; Emax = 130 +/- 16%) than the rings from control patients (pD2 = 6.04 +/- 0.08; Emax = 56 +/- 8% for noradrenaline…
Influence of a Cu–zirconia interface structure on CO2 adsorption and activation
2021
CO2 adsorption and activation on a catalyst are key elementary steps for CO2 conversion to various valuable products. In the present computational study, we screened different Cu–ZrO2 interface structures and analyzed the influence of the interface structure on CO2 binding strength using density functional theory calculations. Our results demonstrate that a Cu nanorod favors one position on both tetragonal and monoclinic ZrO2 surfaces, where the bottom Cu atoms are placed close to the lattice oxygens. In agreement with previous calculations, we find that CO2 prefers a bent bidentate configuration at the Cu–ZrO2 interface and the molecule is clearly activated being negatively charged. Strain…
Globally Optimized Equilibrium Shapes of Zirconia-Supported Rh and Pt Nanoclusters: Insights into Site Assembly and Reactivity
2019
Metal–support interfaces form an active site for many important catalytic reactions. The modeling of these interfacial sites calls for approximations to set up a structure model, which in turn may ...
Thermal Decomposition and Combustion of Microwave Pre-Treated Biomass Pellets
2021
The objective of the study was to investigate a more effective use of commercially available biomass pellets (wheat straw, wood, peat) using microwave pretreatment to improve heat production. Pellets were pretreated using the originally designed microwave torrefaction device. The effects of microwave (mw) pretreatment were quantified, providing measurements of the weight loss and elemental composition of pellets and estimating the effect of mw pretreatment on their porosity, surface area and calorific values at pretreatment temperatures of T = 448–553 K. Obtained results show that the highest structural variations and elemental composition during mw pretreatment were obtained for wheat stra…
Improvement of oxidation resistance of polymer-based nanocomposites through sonication of carbonaceous nanoparticles
2020
Abstract The work aim is focused on two different aspects: first, the investigation of the effect of extended ultra-sound-assisted treatment (us) of carbonaceous nanoparticles, such as carbon nanotubes (CNTs) and carbon black (CB), on their radical scavenging activity, and second, the investigation of the oxidative resistance of polymer-based nanocomposites, containing us-treated CNTs and CB. Particularly, the CNTs and CB have been subjected to us sonication for different time intervals and the performed analysis reveals that both kinds of nanoparticles show decreased average hydrodynamic diameters and large content of surface defects. Really, the increased content of CNTs and CB defects, a…
Water-soluble carbon nanotubes through sugar azide functionalization
2011
In this work we report a covalent functionalization of pristine single-walled carbon nanotubes (SWCNTs) directly with three sugar azides, 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl, 2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl or 2,3,4,6-tetra-O-acetyl-β-d-mannopyranosyl azide. Microwave-assisted functionalization was carried out for SWCNTs prepared with the HiPCO method. The as-prepared, new type of sugar-functionalized SWCNTs were analyzed by Raman and IR spectroscopy. Deacetylation of the functionalized tubes by sodium methoxide yielded nitrogen-linked, sugar-functionalized carbon nanotubes (CNTs) that formed stable dispersions in water. Reactivity of the sugar azides towards SWCNTs was es…
Enhancement of self-sustaining reaction Cu3Si phase formation starting from mechanically activated powders
2000
Mechanical high-energy ball milling of an 3Cu Si elemental powders mixture was used to activate a self-sustaining combustion reaction or so-called self-sustaining high-temperature synthesis (SHS) to form the copper silicide phase, a reaction for which the thermodynamic criterion proposed by Munir for self-propagation reaction is not favorable. A complete characterization of the end-products was performed with X-ray diffraction analysis and scanning electron microscopy. Thermal and structural information describing the combustion front initiated by heating up a sample to 180°C in a Cu:Si system is communicated. This paper clearly shows that the mechanically activated self-sustaining high-tem…