Search results for "banda"

Xyloglucan-based hydrogel films for wound dressing: Structure-property relationships

2017

Thin xyloglucan-based hydrogel films have been synthetized and characterized in the prospect of producing wound dressings. Polyvinyl alcohol (PVA) and glycerol (Gro) were added to have an optimal combination of softness, conformability and resilience. Physical hydrogels have been transformed into permanent covalent hydrogels by reaction with glutaraldehyde (GA). Network structure-process-property relationships are discussed on the account of the results of several complementary characterizations: FTIR, rheology, thermal analysis, morphological analysis, moisture retention and swelling measurements. Selected formulations were also subjected to preliminary in vitro cytotoxicity tests. The phy…

Investigation of absorber and heterojunction in the pure sulphide kesterite

2021

This paper aims to study the properties of the absorber layer and the heterojunction in kesterite solar cells. The Cu2ZnSnS4 (CZTS) thin films were layered on a glass substrate from a colloidal solution of metal salts and thiourea dissolved in a mixture of water and ethanol and deposited by spin coating technique. The samples were then heat treated in a furnace, in the presence of sulphur powder and under a nitrogen gas flow. The results revealed the formation of homogeneous layers of a pure kesterite phase of CZTS crystallites after heat treatment with correct stoichiometry and oxidation states. The optical transmission measurements indicate an energy band-gap of 1.4 eV and an absorption c…

Elastic Superhydrophobic and Photocatalytic Active Films Used as Blood Repellent Dressing.

2020

Durable and biocompatible superhydrophobic surfaces are of significant potential use in biomedical applications. Here, a nonfluorinated, elastic, superhydrophobic film that can be used for medical wound dressings to enhance their hemostasis function is introduced. The film is formed by titanium dioxide nanoparticles, which are chemically crosslinked in a poly(dimethylsiloxane) (PDMS) matrix. The PDMS crosslinks result in large strain elasticity of the film, so that it conforms to deformations of the substrate. The photocatalytic activity of the titanium dioxide provides surfaces with both self-cleaning and antibacterial properties. Facile coating of conventional wound dressings is demonstra…

An asymmetric electrospun membrane for the controlled release of ciprofloxacin and FGF-2: Evaluation of antimicrobial and chemoattractant properties.

2021

Here, an asymmetric double-layer membrane has been designed and fabricated by electrospinning as a tool for a potential wound healing application. A hydrophobic layer has been produced by using a polyurethane-polycaprolactone (PU-PCL) copolymer and loaded with the antibacterial ciprofloxacin whereas an ion responsive hydrophilic layer has been produced by using an octyl derivative of gellan gum (GG-C8) and polyvinyl alcohol (PVA) and loaded with the growth factor FGF-2. This study investigated how the properties of this asymmetric membrane loaded with actives, were influenced by the ionotropic crosslinking of the hydrophilic layer. In particular, the treatment in DPBS and the crosslinking i…

Effect of calcium hydroxide dressing on microleakage of composite restorations in endodontically treated teeth subsequent to bleaching

2009

Objective: This study evaluates the effect of calcium hydroxide dressing on microleakage of composite restorations following non-vital bleaching. Methods: A total of 45 sound extracted human maxillary central incisors underwent endodontic treatment. The teeth were randomly divided into three groups (n=15). In group 1, access cavities were restored with composite. In group 2, the teeth underwent a bleaching procedure for one week before being restored with composite. In group 3, following a bleaching procedure, calcium hydroxide paste was placed in the pulp chamber for one week. The teeth were then restored with composite. The specimens were subjected to a dye leakage test. The data was anal…

El tipo de cambio real dólar-euro y el diferencial de intereses reales

2006

This paper investigates whether threshold effects exist in the relationship between dollar-euro real exchange rate and real interest differential, over the period January 1984 to December 2004. We specify a three-regime threshold model and the results provide evidence that there is no threshold effect in the short term, but the nonlinear behaviour of real exchange rate implies threshold effect in the long term. On the other hand, the nonlinearity into the behaviour of real exchange rates can be modelled by a Band-TAR which implies a symmetric response to the real interest differential outside the bank. Finally, into the threshold band the behaviour of real exchange rate is near to follow a …

The UWB-OFDM Channel Analysis in Frequency

2009

In this paper, the ultra-wideband channel with orthogonal frequency division multiplexing (UWB-OFDM) is analyzed in the frequency domain. For UWB-OFDM channels with log-normal fading in the time domain, we show that the amplitude of each subcarrier can be approximated by a Nakagami-m random variable, where the fading parameter, the mean power and the correlation coefficient are expressed in terms of the following parameters: time arrival of the clusters, inter-arrival time of rays inside clusters, and power decay constants of rays and clusters.

Izquierda en desbandada / 1

2007

La significación de Chapí en la vida musical valenciana

2012

En este trabajo se analiza la significación que el gran compositor de música escénica Ruperto Chapí tuvo en la vida musical valenciana, tanto durante su vida como en los años posteriores a su muerte. Por ello, el análisis se centra en la repercusión y el impacto que su participación directa produjo en diferentes campos de la actividad musical autóctona. Ello hace que se descarte el estudio de la recepción de sus zarzuelas en el ámbito valenciano. El análisis de esta significación se centra en la vida musical de Valencia y, en menor medida, en la de Alicante. Su presencia se puede constatar en torno a actividades relacionadas con la educación musical, las entidades culturales o los concursos…

DETERMINAZIONE DELLA DURATA A FATICA DI COMPONENTI SOGGETTI A SOLLECITAZIONI SCHEMATIZZABILI COME PROCESSI ALEATORI A BANDA STRETTA

2016

In questo lavoro sono state sviluppate le espressioni analitiche per la determinazione della durata a fatica di componenti soggetti a svariate tipologie di sollecitazione aleatorie a banda stretta (con parametro di irregolarità 0.9<aX≤1), in particolare: processi non stazionari di tipo separabile, tensione normale monoassiale con tensione media costante, sollecitazione biassiale con tensioni normali agenti in fase, sollecitazione di sforzo normale e tensione tangenziale agenti in fase, propagazione della frattura. In this paper the analytical equations for the determination of the fatigue life of components subjected to various types of narrowband random processes of stress (having irregula…