Search results for "RADIATION"
showing 10 items of 5298 documents
Photomagnetic effect in a cyanide-bridged mixed-valence {FeII2FeIII2} molecular square
2012
The self-assembly of [Fe(III)(Tp)(CN)(3)](-) and [Fe(II)(bik)(2)(S)(2)](2+) affords the cyanide-bridged mixed valence {Fe(III)(2)Fe(II)(2)}(2+) molecular square, which exhibits a photomagnetic effect under laser light irradiation at low temperature and also shows thermal spin-state conversion near ambient temperature.
Reactive oxygen species activation of MAPK pathway results in VEGF upregulation as an undesired irradiation response
2013
Background Radioresistance limits the effectiveness of radiotherapy in head and neck squamous cell carcinoma. We previously demonstrated post-radiogenic mitogen-activated protein kinase (MAPK) pathway activation and vascular endothelial growth factor (VEGF) release resulting in reduced tumor cell response. Here, we examined the association of this mechanism with the induction of reactive oxygen species (ROS) under irradiation (IR). Methods Intracellular ROS after IR were measured. We modeled radiation-induced ROS by exposure of two SCC lines to H2O2 and evaluated the impact of irradiation and ROS on ERK phosphorylation by Western blot, immunohistochemistry, and ELISA. Results We found eleva…
Anticancer therapy-induced vascular toxicity: VEGF inhibition and beyond
2017
Cardiotoxicity induced by chemotherapeutic agents and radiotherapy is a growing problem. In recent years, an increasing number of new drugs with targeted action have been designed. These molecules, such as monoclonal antibodies and tyrosine kinase inhibitors, can cause different type of toxicities compared to traditional chemotherapy. However, they can also cause cardiac complications such as heart failure, arterial hypertension, QT interval prolongation and arrhythmias. Currently, a field of intense research is the vascular toxicity induced by new biologic drugs, particularly those which inhibit vascular endothelial growth factor (VEGF) and its receptor (VEGF-R) and other tyrosine kinases.…
The optimisation of the angle of inclination of a solar collector to maximise the incident solar radiation
1999
Abstract Irradiation data, recorded on vertical surfaces facing north, south, east and west and on a horizontal surface every ten minutes during daylight hours from January–December 1992 in Valencia, Spain, have been compared with estimated solar irradiation from inclined-surface models. Results show that Hays model most accurately reproduces the variation in irradiation on all vertical surfaces. Hays model has been used to find the hourly variation in the optimum tilt angle for a South-facing solar collector in Valencia, Spain, and also to calculate the yearly average of this angle. This method has been compared with the results provided by another model that uses average monthly values of…
Mesoscopic and Microscopic Investigation on Poly(vinyl alcohol) Hydrogels in the Presence of Sodium Decylsulfate
2007
The structure of poly(vinyl alcohol) (PVA) hydrogels formed as a result of freeze/thaw treatments of aqueous solutions of the polymer (11 wt % PVA) in the freshly prepared state is analyzed through the combined use of small (SANS) and ultrasmall (USANS) angle neutron scattering techniques. The structure of these hydrogels may be described in terms of polymer rich regions, with dimensions of the order of 1-2 microm, dispersed in a water rich phase, forming two bicontinuous phases. The PVA chains in the polymer rich phase form a network where the cross-linking points are mainly crystalline aggregates of PVA having average dimensions of approximately 45 A. The structural organization of freeze…
E-beam crosslinked, biocompatible functional hydrogels incorporating polyaniline nanoparticles
2012
Abstract PANI aqueous nanocolloids in their acid-doped, inherently conductive form were synthesised by means of suitable water soluble polymers used as stabilisers. In particular, poly(vinyl alcohol) (PVA) or chitosan (CT) was used to stabilise PANI nanoparticles, thus preventing PANI precipitation during synthesis and upon storage. Subsequently, e-beam irradiation of the PANI dispersions has been performed with a 12 MeV Linac accelerator. PVA-PANI nanocolloid has been transformed into a PVA-PANI hydrogel nanocomposite by radiation induced crosslinking of PVA. CT-PANI nanoparticles dispersion, in turn, was added to PVA to obtain wall-to-wall gels, as chitosan mainly undergoes chain scission…
Microgels of polyaspartamide and poly(ethylene glycol) derivatives obtained by γ-irradiation
2002
Abstract The copolymer PHG based on α , β -poly( N -2-hydroxyethyl)- dl -aspartamide (PHEA) functionalized with glycidyl methacrylate has been exposed in aqueous solution to a γ -ray source at different irradiation doses (2, 2.5 and 3.5 kGy), alone or in combination with poly(ethylene glycol)dimethacrylate (PEGDMA) or poly(ethylene glycol)diacrylate (PEGDA). The irradiation produces microgel systems that have been characterized by viscosity measurements. Lyophilization of microgels gives rise to samples able to swell instantaneously in water whereas their treatment with acetone produces swellable microparticles that have been characterized.
Adénocarcinome de la glande lacrymale dans un rétinoblastome bilatéral traité avec radiothérapie externe : à propos d’un cas
2011
This clinical case report describes the clinical findings and diagnosis of lacrimal gland adenocarcinoma that developed 20 years after external beam radiotherapy in the treatment of bilateral retinoblastoma. Visual acuity, slit lamp biomicroscopy, fundus color photography, nuclear magnetic resonance, lateral orbitotomy and histological analysis are described.
Density Functional Theory Modelled Absorption and Raman Spectra Applicable to Ergocalciferol (Vitamin D2) and Cholecalciferol (D3)
2021
The study establishes optically relevant lines by modelling ergocalciferol (D2) and cholecalciferol (D3) and compare these to measured and earlier reported absorption and Raman spectra lines. This is a step to reach a further goal of finding if minute Vitamin D (D2 and D3) concentration changes could be determined so that a non-invasive sensor could be developed with a reference to non-invasive measurements reported in [1] describing a Raman spectroscopy method of blood glucose concentration of threshold of 5 mmol/l. However, our concentrations are lower by two orders, i.e., 50 nmol/l. At such concentrations random-type metabolites may have an important role, like those related with person’…
Structural-relaxation phenomena in As–S glasses as probed by combined PAL/DBAR technique
2015
Abstract Experimental techniques exploring phenomena of positron–electron interaction, namely the positron annihilation lifetime spectroscopy and Doppler broadening of annihilation radiation, are shown to be very informative tools to study radiation- and thermally-induced phenomena in chalcogenide glasses of binary As–S system. Time-dependent processes of free-volume voids agglomeration (expansion), fragmentation (refining) and disappearing (contraction) are identified as main stages of physical aging in S-rich glasses, while a competitive channel of coordination topological defects formation associated with void charging becomes significant in a vicinity of near-stoichiometric glass compos…