Increasing the photocatalytic and fungicide activities of Ag3PO4 microcrystals under visible-light irradiation

The present study reports for the first time the performance of silver phosphate (Ag₃PO₄) microcrystals as photocatalyst (degradation of Rodamine B-RhB) and antifungal agent (against Candida albicans–C. albicans) under visible-light irradiation (455 nm). Ag₃PO₄ microcrystals were synthesized by a simple co-precipitation (CP) method at room temperature. The structural and electronic properties of the as-synthetized Ag₃PO₄ have been investigated before and after 4 cycles of RhB degradation under visible light using X-ray diffraction (XRD), micro-Raman spectroscopy, UV–Vis spectrophotometer and field emission scanning electron microscopy (FE-SEM) images. The antifungal activity was analyzed in planktonic cells and 48h-biofilm of C. albicans by colony forming units (CFU) counting, confocal laser and FE-SE microscopies. Statistical analysis was carried out using SPSS software. Morphological and structural modifications of Ag₃PO₄ were observed upon recycling. After 4 recycles, the material maintained its photodegradation property; an eightfold increase in the efficiency of Ag₃PO₄ was observed in planktonic cells and a two fold increase in biofilm when irradiated under visible light. Thus, higher antifungal effectiveness against C. albicans was obtained when associated with visible-light irradiation.     

Study of a BGO calorimeter using electron and hadron beams from 1 to 50 GeV

A calorimeter of 25 bismuth germanate (BGO) crystals equipped with silicon photodiode readout has been tested at the CERN SPS in the energy range 1–50 GeV. The response for electrons has been shown to be linear in this energy range and the rms resolution obtained ( ) is approximately 1%, for E > 4 GeV. The electron/pion separation was found to be better than 1:500 in the energy range 1–20 GeV. Data on lateral and longitudinal shower development were compared with the results of a Monte Carlo simulation using the SLAC-EGS program and found to be in good agreement.     

On the stabilizing behavior of zirconia: A Combined experimental and theoretical study

Reactive zirconia powder was synthesized by the complexation of zirconium metal from zirconium hydroxide using a solution of 8-hydroxiquinoline. The kinetics of zirconia crystallization was followed by X-ray diffraction, scanning electron microscopy and surface area measured by the nitrogen adsorption/desorption technique. The results indicated that zirconia with a surface area as high as 100 m²/g can be obtained by this method after calcination at 500°C. Zirconia presents three polymorphic phases (monoclinic, tetragonal and cubic), which are reversibly interconversible. The cluster model Zr₄O₈ and Zr₄O₇ ⁺² was used for a theoretical study of the stabilization process. The ab initio RHF method was employed with the Gaussian94 program and the total energies and the energy gap of the different phases were calculated and compared with the experimental energy gap. The theoretical results show good reproducibility of the energy gap for zirconia.     

Ammonia-water absorption machines for refrigeration: theoretical and real performances

In principle, absorption chillers of the ammonia-water type could work at temperatures well below the usual air-conditioning temperatures, arriving at the range 250–260 K, which can be useful for refrigeration applications. This possibility is studied for an air-cooled machine, comparing the results with the experimental data supplied by a manufacturer that recently commercialized such a refrigerator. The prediction is fair, and the study allows an insight into the internal parameters and into the possible behaviour for more severe conditions than those studied.     

Optoelectronic devices towards monolithic integration

Starting from the present state-of-the-art of discrete devices up to the realization of monolithic semiconductor integrated prototypes, an overview of optoelectronic devices for telecommunications is given. Among discrete devices single frequency lasers, tunable and multi-sectionDFB lasers andPIN andAPD photodiode detectors are analysed, including the use of new technologies in progress for a second generation of devices. On the future perspective ofIBCN distribution networks, some economics of the hybrid and monolithic form of integration are attempted. Finally a short outline of the most recent achievements in monolithic integration is presented, taking into particular consideration the activities in this field byEEC ESPRIT andRACE programmes.     

Development of calibration models for quality control in the production of ethylene/propylene copolymers by FTIR spectroscopy,multivariate statistical tools,and artificial neural networks

Principal component regression (PCR), partial least squares (PLS), StepWise ordinary least squares regression (OLS), and back‐propagation artificial neural network (BP‐ANN) are applied here for the determination of the propylene concentration of a set of 83 production samples of ethylene–propylene copolymers from their infrared spectra. The set of available samples was split into (a) a training set, for models calculation; (b) a test set, for selecting the correct number of latent variables in PCR and PLS and the end point of the training phase of BP‐ANN; (c) a production set, for evaluating the predictive ability of the models. The predictive ability of the models is thus evaluated by genuine predictions. The model obtained by StepWise OLS turned out to be the best one, both in fitting and prediction. The study of the breakdown number of samples to be included in the training set showed that at least 52 experiments are necessary to build a reliable and predictive calibration model. It can be concluded that FTIR spectroscopy and OLS can be properly employed for monitoring the synthesis or the final product of ethylene–propylene copolymers, by predicting the concentration of propylene directly along the process line. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Treatment of aggression for an adult diagnosed with schizophrenia at a public psychiatric hospital.

The effectiveness of a behavioral program to treat chronic aggression in an adult male individual diagnosed with schizophrenia at a public psychiatric hospital was evaluated. A behavioral plan was developed to provide the client with positive social interactions, social skills training, and positive reinforcement for prosocial behavior; no negative consequences were implemented. The number of aggressive acts declined with the introduction of the behavioral plan and ultimately remitted even without ongoing reinforcers. This article demonstrates the value of psychological intervention in treating aggression with a treatment-resistant client in an in-patient setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radical abdominopelvic lymphadenectomy: historic perspective and current role in the surgical management of rectal cancer

Radical abdominopelvic lymphadenectomy for rectal cancer is based on the tenet that removal of all potentially involved lymphatic tissue will yield a lower rate of locoregional failure and improve survival. At centers with extensive experience with the procedure, the operating time is only modestly prolonged compared with conventional resection. Blood loss and postoperative hospitalization are not significantly increased. Urinary dysfunction and impotence associated with radical abdominopelvic lymphadenectomy (as high as 80 percent and 76 percent, respectively, in recent series) have been major deterrents to its more routine application. Preservation of the hypogastric plexus and even selective preservation of a unilateral S4 nerve root have been shown to reduce the occurrence of genitourinary complications. Improved five-year survival of 68 percent and local recurrence rates of 5 to 20 percent for TNM Stage III cancers have been achieved with radical abdominopelvic lymphadenectomy. These results compare favorably with recent trials of adjuvant chemoradiation after conventional resection in stage-matched patients. The rationale, evolution, and application of radical abdominopelvic lymphadenectomy to the surgical management of rectal cancer are critically examined. The potential benefits of radical abdominopelvic lymphadenectomy, which have been demonstrated in nonrandomized trials, should be evaluated in a prospective and properly randomized study to clearly establish or refute its efficacy.     

Degradation of lincomycin in aqueous medium: Coupling of solar photocatalysis and membrane separation

The photocatalytic oxidation of a common antibiotic, the lincomycin was carried out in aqueous suspensions of polycrystalline TiO₂ Degussa P25 irradiated by sunlight. In order to improve the performance of the lincomycin degradation a hybrid system consisting of a solar photoreactor with the photocatalyst in suspension coupled with a membrane module, used to confine both photocatalyst and pollutants in the reaction environment, was tested.A preliminary study was carried out in order to determine some kinetics parameters of the drug photodegradation. The influence of initial substrate concentration on the lincomycin photooxidation rate was investigated. The photooxidation rate follows a pseudo-first order kinetics with respect to the lincomycin concentration under the used experimental conditions. The presence of the membrane reactor allows the catalyst separation and to operate in continuous mode as the membranes rejection for lincomycin and its oxidation products was quite high.