1,850 research outputs found
Novel 4h-chromen-4-one, 2h-chromene and chroman derivatives: design, synthesis and biological evaluation
La progettazione e sintesi di nuovi antivirali strutturalmente correlati a flavanoidi e flavonoidi sia naturali che sintetici e lo studio della relativa attività anti-picornavirus dei 4H-cromen-4-oni e 2H-cromeni ha portato ad identificare l’(E)-3-stiril-2H-cromene come un inibitore potente, selettivo e ad ampio spettro d’azione nei confronti dei rhinovirus umani (HRV). l’(E)-3-stiril-2H-cromene è stato perciò selezionato come hit compound sul quale effettuare uno studio sistematico di ottimizzazione della struttura. Sono stati quindi progettati e sintetizzati un ampio numero di arilalchil cromeni, cromanoni e cromoni che sono stati saggiati in vitro nei confronti dei sierotipi 14 e 1B di HRV, scelti come rappresentati rispettivamente dei gruppi A e B di HRV. L’estensione dello screening ad altri virus ad RNA conferma la bassa citotossicità e la selettività dell’azione anti-HRV. Sono stati così selezionati i composti più potenti, ad ampio spettro d’azione anti-HRV e con alto indice terapeutico per valutarne il meccanismo d’azione. I risultati ottenuti sia sulla particella virale che sulla moltiplicazione virale suggeriscono che tutti i composti selezionati si comportano da capsid-binder, interferendo con le prime fasi dell’infezione virale, ma mentre l’(E)-3-stiril-2H-cromene agisce sull’adsorbimento del virus al recettore cellulare gli altri composti studiati non interferiscono in questa fase ma solo sul processo di uncoating. Il risultato è di notevole interesse dal momento che l’utilizzo di combinazioni di farmaci che agiscono su fasi successive della replicazione virale potrebbe essere utile per superare il problema delle mutazioni virali che rendono rapidamente inefficace la monoterapia
Novel 4h-chromen-4-one, 2h-chromene and chroman derivatives: design, synthesis and biological evaluation
La progettazione e sintesi di nuovi antivirali strutturalmente correlati a flavanoidi e flavonoidi sia naturali che sintetici e lo studio della relativa attività anti-picornavirus dei 4H-cromen-4-oni e 2H-cromeni ha portato ad identificare l’(E)-3-stiril-2H-cromene come un inibitore potente, selettivo e ad ampio spettro d’azione nei confronti dei rhinovirus umani (HRV). l’(E)-3-stiril-2H-cromene è stato perciò selezionato come hit compound sul quale effettuare uno studio sistematico di ottimizzazione della struttura. Sono stati quindi progettati e sintetizzati un ampio numero di arilalchil cromeni, cromanoni e cromoni che sono stati saggiati in vitro nei confronti dei sierotipi 14 e 1B di HRV, scelti come rappresentati rispettivamente dei gruppi A e B di HRV. L’estensione dello screening ad altri virus ad RNA conferma la bassa citotossicità e la selettività dell’azione anti-HRV. Sono stati così selezionati i composti più potenti, ad ampio spettro d’azione anti-HRV e con alto indice terapeutico per valutarne il meccanismo d’azione. I risultati ottenuti sia sulla particella virale che sulla moltiplicazione virale suggeriscono che tutti i composti selezionati si comportano da capsid-binder, interferendo con le prime fasi dell’infezione virale, ma mentre l’(E)-3-stiril-2H-cromene agisce sull’adsorbimento del virus al recettore cellulare gli altri composti studiati non interferiscono in questa fase ma solo sul processo di uncoating. Il risultato è di notevole interesse dal momento che l’utilizzo di combinazioni di farmaci che agiscono su fasi successive della replicazione virale potrebbe essere utile per superare il problema delle mutazioni virali che rendono rapidamente inefficace la monoterapia
Holographic duals of 6d RG flows
A notable class of superconformal theories (SCFTs) in six dimensions is
parameterized by an integer , an ADE group , and two nilpotent elements
in . Nilpotent elements have a natural partial ordering,
which has been conjectured to coincide with the hierarchy of
renormalization-group flows among the SCFTs. In this paper we test this
conjecture for , where AdS duals exist in IIA. We work
with a seven-dimensional gauged supergravity, consisting of the gravity
multiplet and two non-Abelian vector multiplets. We show that
this theory has many supersymmetric AdS vacua, determined by two nilpotent
elements, which are naturally interpreted as IIA AdS solutions. The BPS
equations for domain walls connecting two such vacua can be solved
analytically, up to a Nahm equation with certain boundary conditions. The
latter admit a solution connecting two vacua if and only if the corresponding
nilpotent elements are related by the natural partial ordering, in agreement
with the field theory conjecture.Comment: 33 pages, 2 figure
Simulating realistic disk galaxies with a novel sub-resolution ISM model
We present results of cosmological simulations of disk galaxies carried out
with the GADGET-3 TreePM+SPH code, where star formation and stellar feedback
are described using our MUlti Phase Particle Integrator (MUPPI) model. This
description is based on simple multi-phase model of the interstellar medium at
unresolved scales, where mass and energy flows among the components are
explicitly followed by solving a system of ordinary differential equations.
Thermal energy from SNe is injected into the local hot phase, so as to avoid
that it is promptly radiated away. A kinetic feedback prescription generates
the massive outflows needed to avoid the over-production of stars. We use two
sets of zoomed-in initial conditions of isolated cosmological halos with masses
(2-3) * 10^{12} Msun, both available at several resolution levels. In all cases
we obtain spiral galaxies with small bulge-over-total stellar mass ratios (B/T
\approx 0.2), extended stellar and gas disks, flat rotation curves and
realistic values of stellar masses. Gas profiles are relatively flat, molecular
gas is found to dominate at the centre of galaxies, with star formation rates
following the observed Schmidt-Kennicutt relation. Stars kinematically
belonging to the bulge form early, while disk stars show a clear inside-out
formation pattern and mostly form after redshift z=2. However, the baryon
conversion efficiencies in our simulations differ from the relation given by
Moster et al. (2010) at a 3 sigma level, thus indicating that our stellar disks
are still too massive for the Dark Matter halo in which they reside. Results
are found to be remarkably stable against resolution. This further demonstrates
the feasibility of carrying out simulations producing a realistic population of
galaxies within representative cosmological volumes, at a relatively modest
resolution.Comment: 19 pages, 21 figures, MNRAS accepte
Investigation of Nonlinear Pupil Dynamics by Recurrence Quantification Analysis
Pupil is controlled by the autonomous nervous system(ANS). It shows complexmovements and changes of size even in conditions of constant stimulation. The possibility of extracting information on ANS by processing data recorded during a short experiment using a low cost system for pupil investigation is studied. Moreover, the significance of nonlinear information contained in the pupillogram is investigated. We examined 13 healthy subjects in different stationary conditions, considering habitual dental occlusion (HDO) as a weak stimulation of the ANS with respect to the maintenance of the rest position (RP) of the jaw. Images of pupil captured by infrared cameras were processed to estimate position and size on each frame. From such time series, we extracted linear indexes (e.g., average size, average displacement, and spectral parameters) and nonlinear information using recurrence quantification analysis (RQA). Data were classified using multilayer perceptrons and support vector machines trained using different sets of input indexes: the best performance in classification was obtained including nonlinear indexes in the input features. These results indicate that RQA nonlinear indexes provide additional information on pupil dynamics with respect to linear descriptors, allowing the discrimination of even a slight stimulation of the ANS. Their use in the investigation of pathology is suggeste
(E)-3-Heteroarylidenechroman-4-ones as potent and selective monoamine oxidase-B inhibitors
A series of (E)-3-heteroarylidenechroman-4-ones (1a-r) was designed, synthesized and investigated
in vitro for their ability to inhibit the enzymatic activity of both human monoamine oxidase (hMAO)
isoforms, hMAO-A and hMAO-B. All the compounds were found to be selective hMAO-B inhibitors
showing IC50 values in the nanomolar or micromolar range. (E)-5,7-Dichloro-3-{[(2-(dimethylamino)
pyrimidin-5-yl]methylene}chroman-4-one (1c) was the most interesting compound identified in this
study, endowed with higher hMAO-B potency (IC50 ÂĽ 10.58 nM) and selectivity (SI > 9452) with respect
to the reference selective inhibitor selegiline (IC50 ÂĽ 19.60 nM, IC50 > 3431). Molecular modelling studies
were performed for rationalizing at molecular level the target selective inhibition of our compounds,
revealing a remarkable contribution of hydrogen bond network and water solvent
GrGadget: an N-body TreePM relativistic code for cosmological simulations
We present the merging of the Particle-Mesh (PM) relativistic Gevolution code
with the TreePM Gadget-4 code, with the aim of studying general relativity
effects in cosmology. Our code, called GrGadget, is able to track the evolution
of metric perturbations in the weak field limit by using Gevolution's
implementation of a relativistic PM in the Poisson gauge. To achieve this,
starting from Gevolution we have written a C++ library called libgevolution,
that allows a code to access and use the same abstractions and resources that
Gevolution uses for its PM-only N-body simulations. The code works under the
assumption that particle interactions at short distances can be approximated as
Newtonian, so that we can combine the forces computed with a Newtonian Tree
with those computed with a relativistic PM. The result is a TreePM simulation
code that represents metric perturbations at the scales where they are
relevant, while resolving non-linear structures. We validate our code by
closely matching Gadget-4 forces, computed with the Tree switched off, with
those computed with libgevolution in the Newtonian limit. With GrGadget we
obtain a matter power spectrum that is compatible with Newtonian Gadget at
small scales and contains GR features at large scales that are consistent with
results obtained with Gevolution. We demonstrate that, due to the better
resolution of the highly non-linear regime, the representation of the
relativistic fields sampled on the mesh improves with respect to the PM-only
simulations.Comment: 15 pages, 14 figure
Introduzione al determinismo
In questo lavoro di tesi ci si concentra sul problema del determinismo nel mondo della
fisica. Il primo capitolo è dedicato a vari tentativi di definire il determinismo; si parte da
definizioni puramente empiriche fino ad arrivare, in un graduale processo costitutivo, a
quella coinvolgente il concetto di mondi possibili che risulta soddisfacente. Nel secondo
capitolo si analizza il problema del determinismo nella fisica classica, introducendo brevemente
lo spazio-temo classico e trattando poi diversi casi fisici di interesse. Nel terzo
capitolo si discutono le implicazioni che la struttura dello spazio-tempo di Minkowski ha
sul determinismo nel caso della relativitĂ ristretta e si accennano alcune considerazioni
sulla relatività generale. Nel quarto ed ultimo capitolo, infine, è trattato il problema
del determinismo nel caso della meccanica quantistica, analizzando in particolare il
significato di una misurazione e le implicazioni del collasso della funzione d’onda
Use of nano zero-valent iron to reduce inorganic species electrogenerated during anodic oxidation on boron doped diamond anodes
In this paper, the solution coming from an anodic oxidation on boron doped diamond of chloride-containing
solution is treated with addition of nano zero-valent iron (nZVI) to reduce the amount of chlorinated byproducts
into chloride ions. The electrolyzed solutions have been obtained under galvanostatic conditions in
an undivided reactor. The evolution and depletion of all the chlorinated species have been monitored by
spectrophotometry and ion chromatography. The nanoscale iron particles have been synthesized in our
laboratory by a fast and facile method through reaction of FeSO4 and NaBH4 solutions without addition of
dispersants.
The effect on the conversion yield of several operative parameters has been investigated and discussed.
The preliminary results indicate that a nZVI postreatment can be considered a viable technology for the
treatment of solutions containing active chlorine and chlorate. However, the reduction of perchlorate, either in
mixed solutions or alone, requires too drastic conditions to be completed
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