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The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an aqueous solution at room temperature. The physical properties of NiMoO4 are investigated using several techniques, such as X-ray diffraction (XRD), which perfectly fits the crystalline α-form of NiMoO4. Moreover, scanning electron microscope (SEM) images show nanosheet-like particles. The atomic force microscopy (AFM) measurements reveal high roughness of the particle's surface. Furthermore, the investigations into the main electronic levels of α-NiMoO4 suggest a strong UV–visible light absorption. The optical band gap is found to be about 2.36 eV. Then, the photocatalytic activity of the synthesized NiMoO4 nanoparticles (NPs) is tested against methylene blue (MB) dye as a pollutant model. The obtained results reveal good capacity of MB degradation even in the dark. It exhibits a degradation efficiency up to 87% within 60 min, under visible-light illumination, and 44% in the dark. The photocatalytic stability of NiMoO4 NPs is studied as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants. [ABSTRACT FROM AUTHOR]

The grazing incidence x-ray reflectometry was used in this study to characterize an epoxy based polymer (Striasol 500). The possibility of using complementarily reflection and transmission of diffuse x ray has been emphasized. Measurements were made in both “detector scan” and “rocking curve” modes. For the first mode, results have shown that this polymer presents locally a periodic character, with various spacing structures (from 32 to 74 nm), while the rocking curve measurements revealed that the mean orientation of these structures is slightly tilted (about 0.01°) compared to the surface sample. Reproducibility measurements have been equally demostrated showing a short distance order, as the periodic structures are observed only on some parts of the analyzed sample. At last, a stability study has shown that the structure of superficial and deeper parts of polymer varies differently after 15 months. [ABSTRACT FROM AUTHOR]

Purpose: This is a retrospective study to evaluate the efficacy and safety of routine use of electronic portal imaging device (EPID) in intensity-modulated radiation therapy for localised prostate cancer. Materials and methods: Data from 20 patients with localised prostate cancer treated by radical radiotherapy using intensity-modulated technique in Habib Bourguiba Hospital were analysed to define the action levels for pretreatment planer dose distribution of 100 treatment fields and the set-up errors of 418 portal imaging. Pretreatment planar dose distribution was measured with the EPID. The additional dose from repeated portal imaging was determined with treatment planning system. Results: For all 100 fields, the predicted and the measured planar dose distribution agrees well with mean±standard deviation value for γ max=2·31±0·57, γ avg=0·36±0·07 and γ %≤1=98·94%±0·71%, respectively. For the evaluation of set-up errors, the mean total errors with 1 SD in the lateral, longitudinal and vertical directions were 0·11±0·44 cm; 0·02±0·37 cm and −0·02±0·21 cm, respectively. The imaging additional dose was evaluated as 1 cGy per monitor unit. Conclusion: EPID is a useful tool to verify pretreatment dose distribution and to assess the correct field position without a significant increase in the absorbed dose due to the repetition of portal imaging. [ABSTRACT FROM AUTHOR]

A gravimetric surface acoustic wave (SAW) biosensor, based on the biotin-streptavidin and antistreptavidin-streptavidin recognitions, has been carried out. A network analyser and a pulse excitation technique were used to monitor both amplitude and phase changes. The SAW biosensor presented a total selective recognition of streptavidin-antistreptavidin and HRPstreptavidin-antistreptavidin. The presence of HRP (Horseradish peroxidase) affects neither the selectivity nor the sensitivity (of order of 0.25°/nM) of the biosensor, nevertheless, it causes a reduction of binding kinetics by a factor ranging between 2 to 5, as well as a diminution of antistreptavidin saturation concentration (of 40%). Results showed that equilibrium constants can be different, depending on evaluation method (from saturation values or from linear part of the output signal variation according to solution concentration). [ABSTRACT FROM PUBLISHER]