Search results for "Roth"
showing 10 items of 806 documents
Weierstraß’s Approximation Theorem (1885) and his 1886 lecture course revisited
2015
The paper provides new insight into the origins of Weierstras’s 1886 lecture course on the foundations of function theory and of the mimeographed lecture notes connected to this course which were published by the author in German in 1988. A short overview of the content of the lecture course is given; the central role that Weierstras’s famous approximation theorem of 1885 played in it is emphasized. The paper uses archival material recently discovered at the Institut Mittag-Leffler in Djursholm.
An initial study into the suitability of Sicilian ecotypes of Cynodon dactylon (L.) Pers. for turfgrass use
2004
The aim of the study is to evaluate the biodiversity of Cynodon dactylon (L.) Pers. in Sicily (Italy), observing several ecotypes collected in specific areas of the island. The ultimate goal was to identify ecotypes that have the qualitative standards required to establish turfgrasses and/or for specific plant breeding programmes. For each of the 22 bermudagrass ecotypes that were collected from Sicily, leaf texture, stolon internodes length, stolon diameter, turf colour, uniformity and quality rating were the main biometric and qualitative parameters monitored. The speed of recovery was also determined for each ecotype. Interesting variability was recorded in the collected vegetative mater…
Role of prothrombotic polymorphisms in successful or unsuccessful aging.
2011
The study of the genetic profile of centenarians aims to identify the genes and allelic variants which may influence a greater life expectancy and that can be considered as predisposing factors associated to the aging diseases, such as Alzheimer. Centenarians, that represent a cohort of selected survivors, show an hypercoagulability state characterised by striking signs of high coagulation enzyme activity, as directly assessed by the tested higher plasma level of some important factors involved in the haemostasis balance. Anyway, these individuals seem to have a reduced susceptibility to dementia, as well as to cardiovascular events. In this study we analyze the frequencies of Leiden Factor…
Comparison of thiol subproteome of the vent mussel Bathymodiolus azoricus from different Mid-Atlantic Ridge vent sites
2012
Deep-sea hydrothermal mussels Bathymodiolus azoricus live in the mixing zone where hydrothermal fluid mixes with bottom seawater, creating large gradients in the environmental conditions and are one of the most studied hydrothermal species as a model of adaptation to extreme conditions. Thiol proteins, i.e. proteins containing a thiol or sulfhydryl group (SH) play major roles in intracellular stress defense against reactive oxygen species (ROS) and are especially susceptible to oxidation. However, they are not particularly abundant, representing a small percentage of proteins in the total proteome and therefore are difficult to study by proteomic approaches. Activated thiol sepharose (ATS) …
Fenitrothion uptake and bioconcentration in the European eel(Anguilla anguilla)
1994
Eels (Anguilla anguilla) were exposed to 0.02 mg/L of the organophosphorus pesticide fenitrothion during 144 hours in semi‐static conditions. BCF, intBCF, uptake rate constants (Ku) and elimination rate constants (Kd) of fenitrothion were determined in brain, gills, blood and muscle tissues of the eel. A simple one‐compartment model fitted the uptake and elimination characteristics. Plateau were reached at different times in the different tissues: at 24 hr in gills, 72 hr in brain and blood and 120 hr in muscle tissue. BCF were ranged from 117 for blood to 658 for muscle. Muscle tissue showed the highest BCF, intBCF, Ku and the lowest Kd .
Inhibition of Gill Na+,K+-ATPase Activity in the Eel,Anguilla anguilla,by Fenitrothion
1998
European eels (Anguilla anguilla) were exposed to sublethal fenitrothion concentrations (0.02 and 0.04 mg/liter) in a continuous flow-through system for 4 days. Gill Mg2+- and Na+,K+-ATPase activities were evaluated after 2, 8, 12, 24, 32, 48, 56, 72, and 96 h of pesticide exposure. Results indicated that ATPase activity in gill tissue decreased as concentration of fenitrothion increased. Pesticide induced significant inhibitory effects on the Na+, K+-ATPase activity of A. anguilla, ranging from >56% inhibition at a sublethal concentration of 0.02 ppm to >73% inhibition at a sublethal concentration of 0.04 ppm. Eels were exposed to both fenitrothion concentrations for 96 h and then allowed …
Impaired glutathione redox status is associated with decreased survival in two organophosphate-poisoned marine bivalves
2002
Biomonitoring organophosphate (OP) exposure in marine environments is generally achieved by the measurement of acetylcholinesterase activity in bivalves like mussels. However, there is evidence that indicates that oxidative stress may be implied in OP toxicity. The aim of this study was to evaluate the relationship between survival from the OP insecticide fenitrothion and glutathione levels in marine bivalves. Mussels (Mytilus galloprovincialis Lam.) and scallops (Flexopecten flexuosus Poli) were exposed, in a time to death test, to their LC85 of fenitrothion for 96 h. OP-poisoned mussels showed reduced (GSH) and oxidised (GSSG) glutathione depletion in the digestive gland, muscle and gills…
Carbon dioxide degassing from Tuscany and Northern Latium (Italy)
2008
Abstract The CO 2 degassing process from a large area on the Tyrrhenian side of central Italy, probably related to the input into the upper crust of mantle fluids, was investigated in detail through the geochemical study of gas emissions and groundwater. Mass-balance calculations and carbon isotopes show that over 50% of the inorganic carbon in regional groundwater is derived from a deep source highlighting gas−liquid separation processes at depth. The deep carbonate−evaporite regional aquifer acts as the main CO 2 reservoir and when total pressure of the reservoir fluid exceeds hydrostatic pressure, a free gas phase separates from the parent liquid and escapes toward the surface generating…
Constraints on the Cretaceous thermal event in the Transantarctic Mountains from alteration processes in Ferrar flood basalts
1999
Abstract K–Ar and 40 Ar/ 39 Ar incremental-heating analyses on apophyllite formed during hydrothermal alteration of volcanic rocks from the Ferrar Supergroup in North Victoria Land, Antarctica, provide strong evidence for hydrothermal events during mid-Cretaceous time. A last event has been dated at 96.7±0.6 Ma. Variable older ages between 112 and 125 Ma are interpreted as mixed ages of hydrothermal events or may be caused by disturbances of the Ar–Ar system. The Rb–Sr isotope system of the apophyllites is not applicable to dating because a large portion of the Sr is radiogenic and because of Rb-mobility in the crystal structure. Secondary mineralogy suggests a temperature for alteration be…
Functionnalized magnetite nanoparticles for bimodal imaging MRI/PET
2015
Functionalized magnetite nanoparticles for bimodal MRI/PET imagingSuperParamagnetic Iron Oxide Nanoparticles (SPIONs) have been widely studied in the biomedical field due to their promising application as nanodrugs and MRI (Magnetic Resonance Imaging) contrast agents (T2). In this study, magnetite (Fe3O4) nanoparticles have been developed for use as contrast agents for MRI/PET (Positron emission tomography) double imaging. First, functionalized stable superparamagnetic SPIONs have been synthesized in a continuous hydrothermal reactor. During the synthesis, hydrophilic agents (citric acid, LDOPA, DHCA and PHA) have been grafted on the surface of the nanoparticles. The functionalization of th…