Search results for "thermal [radiation]"
showing 10 items of 1167 documents
Spectroscopic study of the loading of cationic porphyrins by carbon nanohorns as high capacity carriers of photoactive molecules to cells
2019
Carbon nanomaterials are attractive candidates for drug delivery due to their high surface area, ease of functionalisation and biocompatibility. This work describes the spectroscopic monitoring of the loading capacity of oxidised carbon nanohorns for two cationic porphyrins. Addition of the COOH functionalised carbon nanohorns to both meso-tetra(4-N-methylpyridyl) free base (H2TMPyP4) and platinum (PtTMPyP4) porphyrin in aqueous solution results in hypochromism of the Soret band and quenching of the porphyrin emission. These changes are used to monitor the non-covalent binding interactions with the nanohorn surface and determine the surface loading. The colloidal stability of the nanohorns …
Effect of actively targeted copolymer coating on solid tumors eradication by gold nanorods-induced hyperthermia.
2020
Efforts in the field of anticancer therapy are increasingly focusing on the development of localized and selective treatments. Photothermal therapy (PTT) can lead to a spatially confined death of cancer cells, exploiting an increasing in temperature generated after UV-NIR irradiation of peculiar materials. Herein, a new actively targeted gold-based drug delivery system, named PHEA-LA-Fol-AuNRs/Iri, was explored for hyperthermia and chemotherapy colon cancer treatment. Gold nanorods were stabilized using a folate-derivative of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA-LA-PEG-FA) as coating agent and then loaded with the antineoplastic drug irinotecan (Iri). The efficacy of empty and i…
Influence of chitin nanocrystals on the dielectric behaviour and conductivity of chitosan-based bionanocomposites
2018
[EN] A series of bionanocomposite films based on chitosan, reinforced with chitin nanocrystals, were developed, and assessed in terms of dielectric behaviour and conductivity by using an experimental methodology that allows avoiding the conductivity contribution and the exclusion of contact and interfacial polarization effects. The dielectric relaxations at low and high frequency and temperatures were modeled by Havriliak-Negami functions. Below the glass transition temperature (Tg), the gamma and beta relaxations were observed, which were related to intramolecular and non-cooperative segmental movements. At higher temperatures, an intermolecular and cooperative macromolecular movement, rel…
Study of the Curing Process of DGEBA Epoxy Resin Through Structural Investigation
2015
In this work, a multi-scale approach with different analytical methods is applied to study the curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin. This monomer, thermally cured using 4,4′-diaminodiphenilsulfone (DDS) as hardener, is analyzed after 10, 45, 90, and 120 min of reaction time at 180 °C to obtain information on samples with different cross-linking densities. Samples are also characterized after extraction in acetone in order to obtain structural information on the insoluble parts. For this purpose, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), solid-state nuclear magnetic resonance (ss-NMR),…
Dielectric spectroscopy of novel thiol-ene/epoxy thermosets obtained from allyl-modified hyperbranched poly (ethyleneimine) and diglycidylether of bi…
2019
[EN] Dielectric Thermal Analysis (DETA) of a series of new thermoset obtained by click chemistry was performed. The new thermosets were obtained by a dual-curing process consisting in a first photochemical thiol-ene, followed by a thermal thiol-epoxy starting from an allyl-terminated hyperbranched poly(ethyleneimine) (HBPEI) and different proportions of diglycidylether of bisphenol A (DGEBA) and the corresponding stoichiometric proportions of pentaerythritol tetrakis (3-mercaptopropionate, PETMP). The dielectric behaviour was obtained experimentally supressing the conductive effects. Two sub-Tg intramolecular non-cooperative gamma and beta relaxations and an intermolecular cooperative alpha…
Historical mortars dating from OSL signal of fine grain fraction enriched in quartz
2013
Abstract In the last years the mortar dating through Optically Stimulated Luminescence (OSL) techniques has become a viable support for chronological estimations (date of construction or restoration episodes) of historical buildings. However, the dating of mortar has still open issues mainly regarding the assessment of the bleaching degree of quartz, the analysis of the OSL processes for this type of samples and the need to do appropriate tests for the most correct evaluation of the equivalent dose. This paper discusses the results obtained by OSL dating (blue diode stimulation) on the polymineral fine grain phase, enriched in quartz, extracted from lime mortar samples collected from differ…
Halogen diffusion in a basaltic melt
2007
Abstract The diffusion of the halogens fluorine, chlorine and bromine was measured in a hawaiitic melt from Mt. Etna at 500 MPa and 1.0 GPa, 1250 to 1450 °C at anhydrous conditions; the diffusion of F and Cl in the melt was also studied with about 3 wt% of dissolved water. Experiments were performed using the diffusion-couple technique in a piston cylinder. Most experiments were performed with only one halogen diffusing between the halogen-enriched and halogen-poor halves of the diffusion couple, but a few experiments with a mixture of halogens (F, Cl and Br) were also performed in order to investigate the possibility of interactions between the halogens during diffusion. Fluorine and chlor…
Synthesis, Characterization, Thermal and Antimicrobial studies of N-substituted Sulfanilamide derivatives
2014
Abstract Four sulfanilamide derivatives N -[4-(phenylsulfamoyl)phenyl]acetamide (1), 4-amino- N -phenylbenzenesulfonamide (2), N -[4-(phenylsulfamoyl)phenyl]benzamide (3) and N -{4-[(3-chlorophenyl)sulfamoyl]phenylbenzamide (4) were synthesized and characterized by Infra-Red (IR), Nuclear Magnetic Resonance (NMR) and UV–visible (UV–Vis) spectra. Also Liquid Chromatographic (LCMS) and High Resolution Mass Spectrometric (HRMS) methods were used. Crystal structures of 1–4 were determined by single crystal X-ray diffraction (XRD) and their conformational and hydrogen bond (HB) network properties were examined with survey of the literature data. Compounds 1 and 2 crystallize in the same orthorho…
Influence of metal ions on thermal aggregation of bovine serum albumin: aggregation kinetics and structural changes
2009
Metal ions are implicated in protein aggregation processes of several neurodegenerative pathologies. In this work the effects of Cu(II) and Zn(II) ions on heat-induced structural modifications of bovine serum albumin (BSA) were studied, with the aim of delineating the role of these ions in the early stages of proteins aggregation kinetics. A joint application of different techniques was used. The aggregate growth was followed by dynamic light scattering measurements, whereas the conformational changes occurring in the protein structure were monitored by Raman and IR spectroscopy. Both in absence and in presence of metal ions, heating treatment gave rise to b-structures to the detriment of a…