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301.
L. Lanotte G. Ausanio V. Iannotti G. Pepe G. Carotenuto L. Nicolais 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(4):485-489
A composite material of a polyethylene matrix filled by a fine silver powder was prepared with different Ag contents and physical
behaviours ranging from insulator to conductor. Ac differential magnetic susceptibility χ measurements show the samples are
paramagnetic up to an Ag concentration of ∼65%. At low temperatures the composite is spin-glass type, whereas the transition
from insulator to conductor corresponds to an abatement of χ at zero magnetizing field. Magneto-conductivity effects have
been observed in resistivity measurements at low temperatures. They can be explained in terms of an effective exchange electronic
scattering mechanism between the conduction electrons and the diluted magnetic moments arising from unpaired electron spins
of boundary silver particles. Moreover, the presence of a broad minimum in the resistivity curve at T = ∼ 20 K, observed in samples with an Ag concentration just above the percolation threshold, addresses to possible interference
effects similar to those reported in disordered materials.
Received 17 October 2000 and Received in final form 22 February 2001 相似文献
302.
303.
Preparation and characterization of nano-sized Ag/PVP composites for optical applications 总被引:2,自引:0,他引:2
G. Carotenuto G.P. Pepe L. Nicolais 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(1):11-17
A modification of the polyol process has enabled the direct synthesis of nm-sized Ag particles with narrow size distribution
and controlled average dimension embedded in a polymeric matrix. Dispersion of colloidal silver was obtained by reduction
of silver nitrate in ethylene-glycol in the presence of a polymeric protective agent (i.e., poly(N-vinylpyrrolidone)) and ultrasounds. The final particle size was controlled by removing the colloid from the reactive
mixture by addition of acetone. The very strong plasmon resonance peak at 410 nm and a feature at 350 nm in the UV-visible
spectra are a clear consequence of the nano-size of dilute Ag particles. The proposed process offers the possibility to effectively
use these synthesised materials for the production of colour filters for advanced optical devices.
Received 10 November 1999 相似文献
304.
305.
Giuseppe Ragosta Pellegrino Musto Mario Abbate Pietro Russo Gennaro Scarinzi 《Macromolecular Symposia》2007,247(1):88-98
Polyimide/silica hybrids were produced by a sol-gel process and were examined in terms of their morphology, dynamic-mechanical properties and mechanical performances. Two types of morphology were obtained by tailoring the composition of the precursor solution mixture, i.e. phase- separated or co-continuous systems. These morphologies were found to exhibit considerably different properties. In particular, co-continuous nanocomposite systems were found much more effective in suppressing molecular relaxation processes than micron sized particulate hybrids. The latter systems, on the other hand, exhibited enhanced ductility and fracture toughness 相似文献
306.
Costantina Maisto Michela Aurilio Anna Morisco Roberta de Marino Monica Josefa Buonanno Recchimuzzo Luciano Carideo Laura DAmbrosio Francesca Di Gennaro Aureliana Esposito Paolo Gaballo Valentina Pirozzi Palmese Valentina Porfidia Marco Raddi Alfredo Rossi Elisabetta Squame Secondo Lastoria 《Molecules (Basel, Switzerland)》2022,27(12)
The aim of this work is to compare [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 PET/CT as imaging agents in patients with prostate cancer (PCa). Comparisons were made by evaluating times and costs of the radiolabeling process, imaging features including pharmacokinetics, and impact on patient management. The analysis of advantages and drawbacks of both radioligands might help to make a better choice based on firm data. For [68Ga]Ga-PSMA-11, the radiochemical yield (RCY) using a low starting activity (L, average activity of 596.55 ± 37.97 MBq) was of 80.98 ± 0.05%, while using a high one (H, average activity of 1436.27 ± 68.68 MBq), the RCY was 71.48 ± 0.04%. Thus, increased starting activities of [68Ga]-chloride negatively influenced the RCY. A similar scenario occurred for [18F]PSMA-1007. The rate of detection of PCa lesions by Positron Emission Tomography/Computed Tomography (PET/CT) was similar for both radioligands, while their distribution in normal organs significantly differed. Furthermore, similar patterns of biodistribution were found among [18F]PSMA-1007, [68Ga]Ga-PSMA-11, and [177Lu]Lu-PSMA-617, the most used agent for RLT. Moreover, the analysis of economical aspects for each single batch of production corrected for the number of allowed PET/CT examinations suggested major advantages of [18F]PSMA-1007 compared with [68Ga]Ga-PSMA-11. Data from this study should support the proper choice in the selection of the PSMA PET radioligand to use on the basis of the cases to study. 相似文献
307.
Settepanella Simona Amendola Gennaro Marengo Luigi Minto Connor 《Computational Management Science》2022,19(4):605-626
Computational Management Science - Members of an organization have conflicting preferences. Principal-agent theory analyzes how and under which conditions this conflict can be resolved by means of... 相似文献
308.
Dr. Gianluigi Albano Dr. Francesco Zinna Francesco Urraci Prof. Maria Annunziata M. Capozzi Prof. Gennaro Pescitelli Prof. Angela Punzi Prof. Lorenzo Di Bari Prof. Gianluca M. Farinola 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(51):e202201178
The chiroptical features of chiral diketopyrrolo[3,4-c]pyrrole (DPP) derivatives have been only marginally investigated to date. In this regard, we have synthesized ad hoc four chiral DPP dyes, functionalized with enantiopure alkyl groups from natural sources either on the lactam moieties or on the terminal positions of the π-conjugated backbone, to promote an efficient self-assembly into chiral supramolecular structures. For each of them, the aggregation modes has been investigated by absorbance and ECD spectroscopies in conditions of solution aggregation and on thin films, considering the effects of deposition technique (drop casting vs. spin coating) and post-deposition operations (solvent and thermal annealing). The effect of the structure of lateral π-conjugated units attached to the central DPP scaffold, as well as that of the position of the alkyl chiral group, has been assessed. ECD revealed superior capability, compared to absorbance spectroscopy, to provide information on the aggregation modes and to detect the possible co-existence of multiple aggregation pathways. 相似文献
309.
Electrochemistry strongly contributed to deepen the understanding and predictability of atom transfer radical polymerization (ATRP) outcomes. Several electrochemical tools have been used to determine thermodynamic and kinetic parameters that are hardly accessible by other techniques. The electrochemical methods presented in this brief review were applied to systems with extremely different ATRP reactivity, providing a rational database of primary reference for further developments of ATRP. 相似文献
310.
Dr. Stefano Tomassi Dr. Anna Maria Trotta Dr. Caterina Ieranò Dr. Francesco Merlino Dr. Anna Messere Dr. Giuseppina Rea Federica Santoro Dr. Diego Brancaccio Prof. Alfonso Carotenuto Vincenzo Maria D'Amore Dr. Francesco Saverio Di Leva Prof. Ettore Novellino Prof. Sandro Cosconati Prof. Luciana Marinelli Dr. Stefania Scala Dr. Salvatore Di Maro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(44):10113-10125
Here we investigated the structural and biological effects ensuing from the disulfide bond replacement of a potent and selective C-X-C chemokine receptor type 4 (CXCR4) peptide antagonist, with 1,4- and 1,5- disubstituted 1,2,3-triazole moieties. Both strategies produced candidates that showed high affinity and selectivity against CXCR4. Notably, when assessed for their ability to modulate the CXCL12-mediated cell migration, the 1,4-triazole variant conserved the antagonistic effect in the low-mid nanomolar range, while the 1,5-triazole one displayed the ability to activate the migration, becoming the first in class low-molecular-weight CXCR4 peptide agonist. By combining NMR and computational studies, we provided a valuable model that highlighted differences in the interactions of the two peptidomimetics with the receptor that could account for their different functional profile. Finally, we envisage that our findings could be translated to different GPCR-interacting peptides for the pursuit of novel chemical probes that could assist in dissecting the complex puzzle of this fundamental class of transmembrane receptors. 相似文献