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Abstract: Organ and tumour motion has a significant impact on the planning and delivery of radiotherapy treatment. At present imaging modality such as four-dimensional computer tomography (4DCT) cannot be used to measure the variability of motion between different respiratory cycles. To create reliable motion models, one needs to acquire volumetric data sets of the lungs with sufficient sampling of the breathing cycle. In this paper we investigate the use of highly parallel MRI to acquire such data. A 32 channel coil in conjunction with a balanced SSFP sequence and a SENSE factor of 6 were used to acquire volumetric data sets in five healthy volunteers. The acquisition was repeated for seven series of different breathing patterns. The data acquired was of sufficient spatial resolution (5 × 5 × 5 mm3) and image quality to carry out automated non-rigid registration. The acquisition rate (c.a. 2 volumes per second) allowed for a meaningful sampling of the different respiratory curves that were automatically obtained from the skin surface motion. This acquisition technique should provide images of high enough quality to create statistical respiratory models. [Copyright &y& Elsevier]

Flotation tests of synthetic mixtures of celestite (SrSO4) and calcite (CaCO3) minerals using sodium dodecyl sulfonate as collector were carried out using a factorial experimental design 23. The independent experimental variables included celestite grade in the feed (50% and 90% SrSO4), conditioning pH (6.5 and 9) and sodium silicate depressant concentration (10−5 and 10−3 M). All experiments were performed at a constant collector concentration (10−4 M) and conditioning time of 15 min. The response variables were recovery and grade of SrSO4 in the concentrate.The factors that had the greatest effect on the grade and recovery of celestite were the celestite grade in the feed (L) and the depressant concentration (C); also the combination of these factors significantly affected the response variables. The highest celestite yield (96% recovery, 98% grade) was obtained when a 90% of celestite grade in the feed was used. [Copyright &y& Elsevier]

A non-invasive, non-destructive monitoring approach using three-dimensional (3D) Magnetic Resonance Imaging (MRI) is proposed to study the iron oxidation process driven by Ferrooxidans’ bacterial activity. This activity is related to the oxidation of Fe 2+ into Fe 3 + . Fe 3 + ion has paramagnetic properties that could be used to visualize its presence using MRI. A novel MRI methodology has been implemented to visualize Fe 3 + in solution with the aim to be used as a marker of iron oxidizer bacteria activity. A proof of concept test has been performed with bacteria in solution and in two solids media: an inert vegetal material (luffa) and solid particles, both dipped in acid solutions. The samples were scanned using a clinical 1.5 T MRI scan at several time points to test the capabilities of detecting different Fe 3+ concentrations in the solution in time, while Ferrous Ion oxidation is driven by Ferrroxidans. The measurements were contrasted with titration methods to account for Ferrous Ion consumption during the process. The result reveals that a characteristic parameter obtained with MRI imaging, known as R 1 relaxivity time measured in Hertz, correlates with Fe 2+ oxidation (increment in Fe 3 + concentration). 3D images of the distribution of Fe 3 + production in the samples were acquired. Results are promising and open opportunities to continue complementary laboratory research at the network porous level to capture the spatial 3D distribution of Ferric Ions as distributed inside the porous network during a bio-reaction test. [ABSTRACT FROM AUTHOR]

The study of bulbar functions, particularly chewing, in patients with Duchenne muscular dystrophy (DMD) is an emerging field; various markers, such as fatty infiltration, have been explored. Increased fatty infiltration of masticatory muscles has been observed in muscle ultrasonography (MUSG), however, this technique has several limitations. Our aim was to measure the fat fraction (FF) of masticatory muscles using quantitative muscle resonance in DMD patients and its correlation with maximum masticatory force (MMF). Multicenter cross-sectional study in 17 healthy men (median age 16 years (interquartile range (IQR) 14-19 years), and in 11 DMD patients (median age 17, IQR 13-21 years). Bilateral MMF was measured with an oral dynamometer and MRI was performed in T1 and mDixon sequences and in the masseter, pterygoid and temporal muscles. The patients were enrolled in the study Magnetic Resonance of Orofacial and Cardiac Muscles as Biomarkers in Children and Adults with DMD. The MMF was 526 Newton (N) in controls and 156N in DMD patients (p<0.05). The muscle volumes of the muscles were 19,883 mm3 in healthy males and 19,392 mm3 in DMD patients. The mean FF was 4% in healthy men and 55% in DMD patients. Both differences were statistically significant (p<0.05). A negative correlation was observed between fatty infiltration and muscle strength (r=-0.78) in healthy patients and in DMD patients. The DMD children in this study presented significantly higher FF and lower MMF than controls. FF correlates with a lower MMF, which could be applied in the clinic and as a biomarker in clinical trials. [ABSTRACT FROM AUTHOR]

This paper presents results of column flotation of silica sand (d80=190 μm) that show typical column heights may adversely affect the performance of the flotation, when relatively dense flotation slurries of floatable mineral are processed. For slurry densities above 20% of solids (w/w), floated under typical conditions (Jg=1.46 cm/s, Jt=1 cm/s, Jww=0.16 cm/s, hf=0.3 m), the bubble–particle aggregate reaches density values close to one losing their buoyancy. Under these conditions, mineralized bubbles accumulate, coalesce (losing a fraction of the particles that transport) and may even be carried out to the tailings discharge, affecting both the recovery and the processing capacity of the column. By reducing the height of the collection zone of the column (hc) this abnormal operation may be substantially mitigated. In this work, recovery increased from 55% to 78% by decreasing hc from 4 to 1.5 m when processing a pulp with 30% of floatable minerals. The paper also discusses the effect of column height upon other important variables. [Copyright &y& Elsevier]