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Egg yolk (EY) thermal pasteurization (TP; 60 °C/3 min) preceded by pressure pre-treatments (50 – 400 MPa/5 min) was evaluated, as an attempt to replace commercial TP (60 °C/6.2 min). These combined treatments inactivated 1.8 to at least 6.1 log10 cycles of Salmonella Senftenberg 775/W, whereas commercial TP achieved 3.3 log10 cycles, probably associated with a reduction of the microorganism's thermal resistance induced by pressure. Generally, soluble protein and total carotenoids of raw EY decreased after treatments, and viscosity and secondary lipid oxidation increased, whereas EY treated by moderate pressure (MP) before a shorter TP (MP-TP) was 1.2-fold less viscous and oxidized than commercial TP EY. Improved emulsifying properties were found for MP-TP EY (1.3 – 1.7-fold), while for commercial TP a more stable emulsion was produced. The fatty acids profile remained stable after treatments, while the volatile profile suffered changes, especially for MP-TP. A traditional dessert prepared with MP-TP (90 MPa) EY showed a greater overall sensory acceptability. Therefore, the results open the possibility to use MP pre-treatments for a subsequently shorter TP, as an alternative to commercial TP, allowing in general to obtain EY with better properties and similar microbial safety.

This study was aimed to investigate the effect of high pressure processing (HPP, 200–600 MPa) on the (i) survival ofListeria innocuaandPediococcus acidilacticiHA-6111-2; (ii) production of bacteriocin bacHA-6111-2 and (iii) activity of bacteriocin against untreated and pressure-treatedL. innocuacells. Inactivation ofP. acidilacticiwas observed for pressures of >300 MPa. However, at this pressure level,L. innocuawas more sensitive. Bacteriocin crude extract was pressure stable, with a decrease for pressures of ≥400 MPa. Pressures of ≤200 MPa did not affect bacteriocin production when compared with non-pressure-treated cells, whereas higher pressures caused a 2- to 4-fold decrease on the maximum level of bacteriocin production. Growth curves ofP. acidilacticiwere fitted with the modified Gompertz model. The lag phase period depended on the magnitude of the pressure applied: there was a delay in the exponential phase as pressure increased and, as a consequence, in the beginning of bacteriocin production. SinceP. acidilacticiHA-6111-2 and its bacteriocin have shown resistance to pressures up to 300–400 MPa, they could be used in combination with HPP in order to improve food safety. [ABSTRACT FROM PUBLISHER]

Thermal–pressure treatments for metallic glasses (MGs) rejuvenation involve large pressures up to tens of gigapascals. Such conditions can lead to structural changes beyond pure energy excitation that have not been fully explained in the literature. In this work, molecular dynamics simulations were employed to inspect the relationship between pressure treatments and structural properties in CuZr MGs. To this aim, hydrostatic pressure tests up to 70 GPa were performed at constant temperature and several physical parameters were calculated before and after the tests. Significant structural changes were identified at pressures above 50 GPa, leading to higher energy states, increased atomic volume, and larger populations of high centrosymmetric Voronoi polyhedra. Network analysis revealed that the degree of bond connectivity between such polyhedra decreased drastically, reducing their packing efficiency and weakening the structural backbone of the material. Overall, these results provide new insights into structural behaviors previously observed during CuZr MGs rejuvenation at large pressures. [ABSTRACT FROM AUTHOR]

Human tumors are characterized by an abnormal vascular network that develops because of unregulated angiogenesis. This contributes to abnormalities of the tumor microenvironment like hypoxia, acidosis and high interstitial fluid pressure that influence treatment response and patient survival. There is an important clinical need to develop new minimally invasive tools for characterizing the tumor microenvironment at diagnosis, and monitoring changes during treatment with radiotherapy, chemotherapy or new biologically targeted drugs. MR-based imaging approaches offer exciting possibilities that have yet to be fully exploited. Dynamic contrast enhanced (DCE) MR allows the functional characteristics of the tumor vasculature to be interrogated serially over time. Studies in human cancers have shown substantial differences in DCE MR parameters between tumor and normal muscle in keeping with higher blood flow and vascular permeability. DCE MR has been shown to correlate with response to radiotherapy or drugs that specifically target the tumor vasculature. However, despite important advances, MR functional imaging has not been adopted in routine clinical practice, in part because of a lack of consensus on optimal imaging techniques, analysis methods and reporting metrics. Further refinement and standardization is required founded on interdisciplinary collaboration among clinicians, medical imagers, biologists, physicists and mathematicians to make these techniques robust and clinically applicable., Learning Objectives: 1. Discuss the clinical use of MR functional imaging in patients receiving radiotherapy and the challenges to wide-spread clinical utilization. 2. Discuss the value of MR functional imaging as a predictor of clinical outcome in patients receiving radiotherapy, and a means of monitoring biologic response over a course of fractionated treatment. 3. Understand the role of MR functional imaging in the evaluation of new treatment strategies comprised of radiotherapy and drugs that specifically target the tumor vasculature., (© 2012 American Association of Physicists in Medicine.)