80 research outputs found
Intrinsically disordered amphiphilic peptides as potential targets in drug delivery vehicles
Intrinsically disordered proteins/peptides play a crucial role in many physiological and pathological
events and may assume a precise conformation upon binding to a specific target. Recently, we have
described the conformational and functional properties of two linear ester peptides provided with the
following sequences: Y-G-E-C-P-C-K-OAllyl (PepK) and Y-G-E-C-P-C-E-OAllyl (PepE). Both peptides
are characterized by the presence of the ‘‘CPC’’ motif together with a few amino acids able to promote
disorder. The CPC sequence is a binding motif for the CXCR4 receptor that represents a well-known
target for cancer therapies. In this paper, we report on synthetic amphiphilic peptides that consist of
lipophilic derivatives of PepE and PepK bearing two stearic alkyl chains and/or an ethoxylic spacer.
These peptide amphiphiles form stable supramolecular aggregates; they present conformational features
that are typical of intrinsically disordered molecules as shown by CD spectroscopy. Solution
fluorescence and DLS studies have been performed to evaluate Critical Micellar Concentrations and the
dimension of supramolecular aggregates. Moreover, preliminary in vitro cell-based assays have been
conducted to investigate the molecular recognition processes involving the CXCR4 receptor. In the
end, the results obtained have been compared with the previous data generated by the corresponding
non-amphiphilic peptides (PepE and PepK)
NURE: An ERC project to study nuclear reactions for neutrinoless double beta decay
Neutrinoless double beta decay (0νββ) is considered the best potential resource to
access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are
their own anti-particles (Majorana particles). Presently, this physics case is one of the most
important research “beyond Standard Model” and might guide the way towards a Grand
Unified Theory of fundamental interactions.
Since the 0νββ decay process involves nuclei, its analysis necessarily implies nuclear structure
issues. In the NURE project, supported by a Starting Grant of the European Research Council
(ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract
information on the 0νββ Nuclear Matrix Elements. In DCE reactions and ββ decay indeed the
initial and final nuclear states are the same and the transition operators have similar structure.
Thus the measurement of the DCE absolute cross-sections can give crucial information on ββ
matrix elements. In a wider view, the NUMEN international collaboration plans a major
upgrade of the INFN-LNS facilities in the next years in order to increase the experimental
production of nuclei of at least two orders of magnitude, thus making feasible a systematic
study of all the cases of interest as candidates for 0νββ
First Results of the Ce(n,γ)Ce Cross-Section Measurement at n_TOF
An accurate measurement of the Ce(n,γ) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the Ce Maxwellian-averaged cross-section
First Results of the Ce(n,γ)Ce Cross-Section Measurement at n_TOF
An accurate measurement of the Ce(n,γ) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the Ce Maxwellian-averaged cross-section
Measurement of the Cm and Cm Neutron-Induced Cross Sections at the n_TOF Facility
The neutron capture reactions of the Cm and Cm isotopes open the path for the formation of heavier Cm isotopes and of heavier elements such as Bk and Cf in a nuclear reactor. In addition, both isotopes belong to the minor actinides with a large contribution to the decay heat and to the neutron emission in irradiated fuels proposed for the transmutation of nuclear waste and fast critical reactors. The available experimental data for both isotopes are very scarce. We measured the neutron capture cross section with isotopically enriched samples of Cm and Cm provided by JAEA. The measurement covers the range from 1 eV to 250 eV in the n_TOF Experimental Area 2 (EAR-2). In addition, a normalization measurement with the Cm sample was performed at Experimental Area 1 (EAR-1) with the Total Absorption Calorimeter (TAC)
Parte I (iscrizioni inedite). Volsinii. Orvieto, Crocifisso del Tufo. nn. 44-51.
N. 8 schede di epigrafi etrusche inedite dalla necropoli di Crocifisso del Tufo in Orvieto (TR
Thia-Michael Reaction for a Thermostable Itaconic-Based Monomer and the Synthesis of Functionalized Biopolyesters
A new building block, derived from dimethyl itaconate, has been synthesized through thia-Michael addition reaction and then exploited for the synthesis of a series of novel aliphatic polyesters. The new monomer, the dimethyl 2-((octylthio)methyl)succinate, demonstrated a remarkable stability toward common conditions of polycondensation (high temperatures and metal-based catalysts) and was suitable for polycondensation reactions with different diols. The resulting polyesters are characterized by high molecular weights and good stability; they are amorphous polymers with a tunable glass transition temperature depending on the rigidity of the diol. The synthetic approach presented here allows, for the first time, remarkably stable polymeric structures based on itaconic acid, circumventing its inherent thermal lability, to be achieved. Furthermore, by demonstration of the successful exploitation of thia-Michael adducts in polymer science, the bases have been set for the creation of a novel renewable platform based on dimethyl itaconate
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