Search results for "Scale"
showing 10 items of 5180 documents
Cessione di beni (Dir. Trib.)
2002
La voce dell'enciclopedia ha ad oggetto la disciplina fiscale della cessione dei beni.
Tropical Temperate Toughs over southern Africa: mechanisms and evolution in response to climate change
2015
In the Southern Hemisphere, Southern Africa and the south-west Indian Ocean are one of the three preferred regions where interactions between the tropics and midlatitudes develop. This is the South Indian Convergence Zone (SICZ), where northwest-southeast oriented cloud bands form at the synoptic scale (between 3 and 5 days). These bands are mainly found during the austral summer and are commonly referred to as tropical temperate troughs (TTTs). This research aims at improving our knowledge related to TTTs, with a study on the dynamics associated with these systems, and an analysis of their possible evolution during the 21st century.The first part of this thesis aims at identifying favorab…
X-ray Computed Tomography for Capillary Collapse of Loose Unsaturated Sand
2016
Abstract The collapse of unsaturated soils consists of the reduction in volume upon wetting at constant total stress. Several studies at the macro scale outline the influence of initial void ratio, confining pressure and matric suction on the onset of collapse of standard laboratory specimens. Conversely, few observations at the micro scale are available in the literature, although the influence of the particles arrangement and intergranular bonding has been formerly supposed. The collapse of fine sand derived by a pyroclastic soil of Southern Italy is investigated in this paper at the microscale using the X-ray Computed Tomography. The experimental procedure, formerly tested on similar pyr…
The guanidinium group as a key part of water-soluble polymer carriers for siRNA complexation and protection against degradation.
2014
Here, the preparation of a novel block copolymer consisting of a statistical copolymer N-(2-hydroxypropyl) methacrylamide-s-N-(3-aminopropyl) methacrylamide and a short terminal 3-guanidinopropyl methacrylamide block is reported. This polymer structure forms neutral but water-soluble nanosized complexes with siRNA. The siRNA block copolymer complexes are first analyzed using agarose gel electrophoresis and their size is determined with fluorescence correlation spectroscopy. The protective properties of the polymer against RNA degradation are investigated by treating the siRNA block copolymer complexes with RNase V1. Heparin competition assays confirm the efficient release of the cargo in vi…
Microscale magnesium distribution in shell of the Mediterranean mussel Mytilus galloprovincialis: An example of multiple factors controlling Mg/Ca in…
2019
Abstract Since magnesium concentration (Mg/Ca) in biogenic calcite is considered to reflect water temperature during precipitation, the magnesium-to‑calcium ratio has been examined as a proxy for water temperature in paleoclimate research, although factors other than temperature may also influence Mg/Ca in biogenic calcite, thereby introducing a potential bias in the relationship between Mg/Ca and temperature observed in inorganic systems. To better understand factors controlling Mg incorporation into the calcitic shells of bivalves, the distribution of Mg in the Mediterranean mussel Mytilus galloprovincialis was studied, being compared with ambient sea surface temperature (SST), shell grow…
Thermo-, piezo-, photo- and chemo-switchable spin crossover iron(II)-metallocyanate based coordination polymers
2011
Abstract The design of coordination polymers (CPs) with switch and memory functions is an important subject of current interest in the search for new advanced materials with potential applications. Implementation of CPs with electronically labile iron(II) building blocks able to undergo cooperative spin crossover (SCO) behavior is a singular approach to this end. This review provides an up to date survey of a new generation of iron(II)-metallocyanate based spin crossover coordination polymers (SCO-CPs) developed during the last decade. These new solids feature structural diversity, supramolecular isomerism, interpenetrating frameworks, structure flexibility, reversible solid-state chemical …
Correlation between hydrophobicity of amino acids and retention data in reversed-phase liquid chromatography with micellar eluents
1995
Hydrophobic character is usually expressed in terms of the partition coefficient in 1-octanol-water (log PO/W). However, measurement of this coefficient is often problematic. Retention in micellar liquid chromatography is mainly due to hydrophobic interactions and can also be used as an index of hydrophobicity. A hydrophobicity scale was established with retention data foro-phthalaldehyde (OPA)-N-acetyl-L-cysteine (NAC) amino acid derivatives, using the glycine derivative as reference. Since the OPA-NAC derivatives only differ in the nature of R1 in the amino acid (R1CH(COOH)NH2), in the absence of electrostatic interactions the hydrophobic character of the substituent was responsible for r…
Polymeric janus particles.
2009
Since de Gennes' Nobel lecture in 1991, in which he coined the term "Janus grains", research into asymmetric particles has boomed. Macroscopic, microscopic and nanoscopic particles have been prepared in which certain parts of their surface differ in chemical composition, polarity, color, or any other property. Spherical, cylindrical, disc-like, snowman-, hamburger-, and raspberry-like structures have been synthesized from organic or inorganic materials or even as hybrids of both. Synthetic strategies towards such particles vary greatly from simple polymer mixtures to the bulk self-assembly of sophisticated terpolymers to immobilization methods of symmetric particles. Polymeric Janus particl…
Glassy dynamics in thin polymer films: recent MD results
2002
The influence of a film geometry on the glass transition is investigated via molecular dynamics (MD) simulations of a (non-entangled) polymer melt. The confinement is realized by two identical potential barriers of the form U wall = z -9 , where z denotes the distance of a particle from the wall. Despite the geometric confinement, basic qualitative features of the system dynamics can be well described in the framework of the mode-coupling theory (MCT). Examples are the two-step relaxation of the incoherent intermediate scattering function, the time-temperature superposition property of the late time α-process and the space-time factorization of the scattering function on the intermediate ti…
Morphology of 1-alkyl-3-methylimidazolium hexafluorophosphate room temperature ionic liquids
2008
The structural organization in selected room temperature ionic liquids, namely (a) butyl-, (b) hexyl- and (c) octyl-3-methylimidazolium hexafluorophosphate, is investigated by means of X-ray diffraction. We find novel experimental evidences of the existence of a high degree of intermediate range order that is associated to nanoscale segregation of the alkyl chains into the charged matrix. The size of these structural heterogeneities depends linearly from the alkyl chain length. A similar behaviour had been observed in other systems, such as normal alcohols. The slope of such dependence provides hints on the nature of the structural organization of these segregated domains.