Search results for "Roca"
showing 10 items of 1893 documents
Oligooctenamere, charakterisierung und massenspektrometrische untersuchungen
1974
Die homologe Reihe der Oligomeren des Cyclooctens wurde mit Hilfe der Metathese-Reaktion dargestellt; die Oligomeren wurden gelchromatographisch getrennt und gereinigt. Ihre Siedepunkte und Brechungsindices wurden bestimmt, und ihr spektroskopisches Verhalten wurde untersucht. Insbesondere werden die Massenspektren der Oligomeren im Vergleich zu denen der Oligomeren des Cyclododecens, des 1,5-Cyclooctadiens und acyclischer Oligobutadiene diskutiert. Die Ergebnisse bestatigen die cyclische Struktur der durch ringoffnende Polymerisation von Cycloolefinen erhaltenen Oligomeren. Daruberhinaus wird gezeigt, das die Massenspektrometrie unter geeigneten Bedingungen herangezogen werden kann, um zwi…
Vanadium‐Doped Zircon and Zirconia Materials Prepared from Gel Precursors as Site‐Selective Electrochemical Sensors
2003
Abstract Polymer film electrodes incorporating vanadium‐doped zircon (V x ZrSiO4, 0.00 < x < 0.10) and vanadium‐doped monoclinic and tetragonal zirconias (V x ZrO2, 0.00 < x < 0.15), prepared by heat treatment of gel precursors, exhibit a significant site‐selective electrocatalytic activity towards the oxidation of amino acids, polyalcohols, and polyhydroxycarboxylic acids in alkaline media. Catalysis of the oxidation of carboxylate and alcohol groups involves a relatively slow chemical reaction between the substrate and vanadium centers, while the oxidation of thiolate in cysteine can be attributed to the oxidation of an adduct formed by vanadium centers and the substrate.
Perfluorocarbons–graphene oxide nanoplatforms as biocompatible oxygen reservoirs
2018
Abstract 3-Pentadecafluoroheptyl,5-perfluorophenyl-1,2,4-oxadiazole (FOX) molecules were attached onto a graphene oxide (GO) via a facile aromatic substitution in alkaline environment. This approach allows achieving high degree of functionalization under mild conditions. The covalent attachment of perfluoromoieties onto GO lamellae was confirmed by spectroscopic analyses. The performance of these nanoplatforms (GOF) as oxygen reservoirs was assessed at different concentrations and temperature. The results revealed that under physiologic conditions GO and FOX synergistically operate for increasing oxygen uptake and release, either from a thermodynamic and a kinetic point of view. Even at low…
Vulnerability maps pollution to hydrocarbon and urban waste pollution in seawater intrusion areas
2004
De acuerdo con un proyecto nacional promovido por el Grupo Nacional Italiano para la Protección contra Riesgos Hidrogeológicos han sido publicados los mapas de vulnerabilidad (1:50.000) de parte del Territorio Italiano, particularmente algunos mapas de Sicilia: Montes Iblei, Moadonie, Sicani y el Monte Etna. Estos mapas se han vuelto documentos públicos para el manejo local del agua subterránea. Algunos fenómenos muy peligrosos han sido reportados en algunas áreas de Sicilia. Intervenciones antrópicas han creado basureros de residuos tóxicos sobre áreas vulnerables. Esta investigación explica las ventajas del uso de mapas de vulnerabilidad en estudio de tipos peligrosos de contaminación par…
Reciprocal lower bound on modulus of curve families in metric surfaces
2019
We prove that any metric space $X$ homeomorphic to $\mathbb{R}^2$ with locally finite Hausdorff 2-measure satisfies a reciprocal lower bound on modulus of curve families associated to a quadrilateral. More precisely, let $Q \subset X$ be a topological quadrilateral with boundary edges (in cyclic order) denoted by $\zeta_1, \zeta_2, \zeta_3, \zeta_4$ and let $\Gamma(\zeta_i, \zeta_j; Q)$ denote the family of curves in $Q$ connecting $\zeta_i$ and $\zeta_j$; then $\text{mod} \Gamma(\zeta_1, \zeta_3; Q) \text{mod} \Gamma(\zeta_2, \zeta_4; Q) \geq 1/\kappa$ for $\kappa = 2000^2\cdot (4/\pi)^2$. This answers a question concerning minimal hypotheses under which a metric space admits a quasiconfor…
Molecular studies on the toxifying effects by genetically engineered cytochromes P450.
1999
After almost two decades, it is now evident that methodology based on molecular biology and gene technology has dramatically changed the way basic and applied toxicology is being performed. It star...
Inheritance of resistance to aBacillus thuringiensistoxin in a field population of diamondback moth (Plutella xylostella)
1995
Inheritance of resistance to the Bacillus thuringiensis Berl. CryIA(b) crystal protein was studied in Plutella xylostella L. (diamondback moth). A field population 50-fold more resistant to CryIA(b) than a control susceptible strain was used. Dose-mortality curves of the resistant population, the susceptible strain and the F 1 from the two reciprocal crosses were compared. Resistance transmission to the F 1 was dependent on the sex of the resistant progenitor. Sex ratio of the survivors to high doses of CryIA(b) in the F 1 of the two reciprocal crosses did not corroborate the preliminary hypothesis of resistance being due to a recessive sex-linked allele. Since, in a previous work, the loss…
Preliminary insights about the treatment of contaminated marine sediments by means of bioslurry reactor: Process evaluation and microbiological chara…
2022
Abstract Contaminated marine sediments represent a critical threat towards human health and ecosystems, since they constitute a potential reservoir of toxic compounds release. In the present study, a bioslurry reactor was studied for the treatment of real marine sediments contaminated by petroleum hydrocarbons. The experimental campaign was divided in two periods: in the first period, microcosm trials were carried out to achieve useful indicators for biological hydrocarbon removal from sediments. The microcosm trials highlighted that the inoculum of halotolerant allochthonous bacteria provided the highest performance followed by autochthonous biomass. Based on the achieved results, in the s…
Hydrocarbons removal from real marine sediments: Analysis of degradation pathways and microbial community development during bioslurry treatment
2022
In this study, real marine sediments polluted by petroleum compounds were treated by means of a bioslurry pilot scale reactor. The treatment performance was evaluated by measuring the removal of total petroleum hydrocarbon (TPH), coupled to further analyses required to understand the mechanisms involved in the biodegradation process. The maximum TPH-removal efficiency reached 86 % at the end of experiments. Moreover, high throughput 16S RNA gene sequencing was used to describe the microbiome composition in sediment prior to, and after, bioslurry treatment, in order to identify the taxa mostly entailed in the TPH removal process. The raw sediment was mostly colonized by members of Sulfurimon…
Polybrominated methoxy diphenyl ethers (MeO-PBDEs) in fish and guillemot of Baltic, Atlantic and Arctic environments
2003
Arctic cod liver samples from Vestertana Fjord at the Arctic coast of Norway, salmon and guillemot samples from the Baltic Sea and the Atlantic Ocean, and salmon and lamprey larva samples from Kymijoki River in southern Finland were analysed for the occurrence of tri-, tetra- and pentabromomethoxy diphenyl ethers and their concentration levels were estimated. These compounds have previously been identified by other research groups in salmon, seal and dolphin samples. The aim of this study was to find out a possible temporal trend in the concentrations of these compounds in the cod liver samples from years 1987-1998 and to investigate the possible spatial differences in the concentrations in…