Biomedical subjects

J Iniesta

Publications and source records attributed to J Iniesta.

7 recordsLinked to original sources

PubMed2006

Optimisation of 20 kHz sonoreactor geometry on the basis of numerical simulation of local ultrasonic intensity and qualitative comparison with experimental results.

The intensity distribution of the ultrasonic energy is, after the frequency, the most significant parameter to characterize ultrasonic fields in any sonochemical experiment. Whereas in the case of low intensity ultrasound the measurement of intensity and its distribution is well solved, in the case of high intensity (when cavitation takes place) the measurement is much more complicated. That is why the predicting the acoustic pressure distribution within the cell is desirable. A numerical solution of the wave equation gave the distribution of intensity within the cell. The calculations together with experimental verification have shown that the whole reactor behaves like a resonator and the energy distribution depends strongly on its shape. The agreement between computational simulations and experiments allowed optimisation of the shape of the sonochemical reactor. The optimal geometry resulted in a strong increase in intensity along a large part of the cell. The advantages of such optimised geometry are (i) the ultrasonic power necessary for obtaining cavitation is low; (ii) low power delivered to the system results in only weak heating, consequently, no cooling is necessary and (iii) the "active volume" is large, i.e. the fraction of the reactor volume with high intensity is large and is not limited to a vicinity close to the horn tip.

Computer Simulation↗

PubMed2005

Characterization of a 20 kHz sonoreactor. Part II: analysis of chemical effects by classical and electrochemical methods.

A new electrochemical redox probe has been investigated in order to characterize the local production of radicals during the cavitation events. The results have been compared with those obtained with Fe(CN)6(3-)/Fe(CN)6(4-) (electrochemical probe for local mechanical effects) and classical chemical methods such as iodide and Fricke dosimeters (chemical probes for global effects).

Aluminum↗

PubMed2005

Characterization of a 20 kHz sonoreactor. Part I: analysis of mechanical effects by classical and numerical methods.

Numerical simulations have been carried out in order to characterize the ultrasonic field propagation and to obtain the spatial distribution of the mechanical effect derived from it. The results have been compared with those obtained with different classical physical methods (calorimetry, aluminium foil erosion, thermal probes) and have given useful information about the influence of the presence of probes and auxiliary tools in the ultrasonic field. All these information have been used for the development of the Part II of this work: analysis of chemical effects, providing an accurate picture of the reaction environment in the sonoreactor used (20 kHz, 100 W supplied by Undatim) for further uses in sonoelectrochemical studies.

Aluminum↗

PubMed2004

Sonovoltammetric studies on copper in buffered alkaline solution.

The effect of ultrasound on the voltammetry of copper in alkaline solution is reported. At pH 7 the electrode surface remains active after scanning to ca. +1.0 V (vs. SCE) and the effects of ultrasound show the expected substantial enhancement in limiting current due to improved mass transport under ultrasound. However at pH 9, whereas the silent scan is only slightly altered in gross detail from that obtained at pH 7, the sonicated scan is significantly different. This shows the expected current increase only up until ca. +0.6 V (vs. SCE), where there is a substantial loss of current showing a passivation phenomenon that is enhanced by ultrasound. In addition, during the reverse (reduction) scan under ultrasound an anodic peak appears. This suggests reactivation of the electrode during the cathodic sweep, possibly by reductive removal of a transient species from the electrode/(hydr)oxide interface at a potential where oxidation still occurs. Increasing the pH to 11 further shifts the cathodic peaks in the silent voltammogram.

Journal Article↗

PubMed2003

Sonoelectrochemical effects in electro-organic systems.

This paper describes recent studies in organic sonoelectrochemistry at Coventry University, including the oxidation of thiophene monoxides, degradation of dye pollutants, formation of conducting polymers and electrosynthetic modification of proteins.

Animals↗

PubMed2001

Influence of chloride ion on electrochemical degradation of phenol in alkaline medium using bismuth doped and pure PbO2 anodes.

Electrochemical method at laboratory scale for the treatment of biorefractory solutions with high phenol content--1000 ppm is described. Total degradation of phenol was obtained at alkaline pH when NaCl was present using Bi-doped and pure lead dioxide electrodes. A filter press cell of 63 cm2 geometric area was used for this purpose. Measurements of chemical oxygen demand (COD), phenol, carbon monoxide, carbon dioxide, and volatile organic compounds (VOCs) have been used to characterise the electrochemical process for phenol elimination. It is worth noting that in the absence of NaCl, the charge efficiency of COD removal was independent of the current density in the range studied (50-100 mA cm(-2)) Moreover, when NaCl was present, the current efficiency for COD and phenol removal increase as the chloride concentration increases. Chloroform was the only halocompound detected at the end of reaction. For both electrodes, Bi-doped and pure lead dioxide, the chloroform concentration at the end of the electrolysis decreases, working at low current densities and for low chloride concentrations.

Anions↗

PubMed1999

[Stesioneuroblastoma. A case report].

The esthesioneuroblastoma is a rare type of tumor located in nasal cavity, malignant, that is able to take a very aggressive growth pattern, but it has treatment with cure expectations when it is discovered in its initial stages by surgery or intensive radiotherapy and/or chemotherapy in the more developed ones. Due to its low incidence and its clinic presentation as a benign process that makes the patient takes it as a non important process, the esthesioneuroblastoma, as others malignant diseases of the nasal cavity, is frequently diagnosed at developed stages as this case that we present here.

Adult↗