A Bayesian approach for energy-based estimation of acoustic aberrations in high intensity focused ultrasound treatment

High intensity focused ultrasound is a non-invasive method for treatment of diseased tissue that uses a beam of ultrasound to generate heat within a small volume. A common challenge in application of this technique is that heterogeneity of the biological medium can defocus the ultrasound beam. Here we reduce the problem of refocusing the beam to the inverse problem of estimating the acoustic aberration due to the biological tissue from acoustic radiative force imaging data. We solve this inverse problem using a Bayesian framework with a hierarchical prior and solve the inverse problem using a Metropolis-within-Gibbs algorithm. The framework is tested using both synthetic and experimental datasets. We demonstrate that our approach has the ability to estimate the aberrations using small datasets, as little as 32 sonication tests, which can lead to significant speedup in the treatment process. Furthermore, our approach is compatible with a wide range of sonication tests and can be applied to other energy-based measurement techniques

Understanding the spiral structure of the Milky Way using the local kinematic groups

We study the spiral arm influence on the solar neighbourhood stellar kinematics. As the nature of the Milky Way (MW) spiral arms is not completely determined, we study two models: the Tight-Winding Approximation (TWA) model, which represents a local approximation, and a model with self-consistent material arms named PERLAS. This is a mass distribution with more abrupt gravitational forces. We perform test particle simulations after tuning the two models to the observational range for the MW spiral arm properties. We explore the effects of the arm properties and find that a significant region of the allowed parameter space favours the appearance of kinematic groups. The velocity distribution is mostly sensitive to the relative spiral arm phase and pattern speed. In all cases the arms induce strong kinematic imprints for pattern speeds around 17 km/s/kpc (close to the 4:1 inner resonance) but no substructure is induced close to corotation. The groups change significantly if one moves only ~0.6 kpc in galactocentric radius, but ~2 kpc in azimuth. The appearance time of each group is different, ranging from 0 to more than 1 Gyr. Recent spiral arms can produce strong kinematic structures. The stellar response to the two potential models is significantly different near the Sun, both in density and kinematics. The PERLAS model triggers more substructure for a larger range of pattern speed values. The kinematic groups can be used to reduce the current uncertainty about the MW spiral structure and to test whether this follows the TWA. However, groups such as the observed ones in the solar vicinity can be reproduced by different parameter combinations. Data from velocity distributions at larger distances are needed for a definitive constraint.Comment: 18 pages, 21 figures, 4 tables; acccepted for publication in MNRA

Educational Innovation: Implementation of the Introductory Physics in Blended Learning

El artículo presenta la experiencia de la asignatura Física Introductoria en la modalidad semipresencial en la PUCMM/RSTA. La implementación del proyecto piloto tuvo varias fases incluyendo desde la preparación de materiales hasta el establecimiento de los elementos de la estrategia y la orientación de los estudiantes en la nueva modalidad. Los resultados se evaluaron utilizando diversas herramientas: cuestionarios, encuestas on-line, entrevistas y pruebas de rendimiento. Éstas fueron orientadas a aspectos relacionados con el estudiante, la asignatura, el profesorado, el contenido, la comunicación y el entorno virtual. Los resultados obtenidos fueron satisfactorios en cada una de las áreas evaluadas, incluida el rendimiento de los estudiantes.The article presents the experience of implementing the introductory physics course in b-learning format in the PUCMM /RSTA. The implementation of the pilot project includes several phases from preparing materials to establish the elements of the new strategy and guidance of students in the new method. The results were evaluated using several tools including questionnaires to students, online surveys, interviews and performance testing. These tools were oriented aspects of the student, the subject as well as aspects related to the teacher, content, communication and the virtual environment. The results were satisfactory in each of the areas evaluated as well as the performance of students

Development of a Patient-Specific Multi-Scale Model to Understand Atherosclerosis and Calcification Locations: Comparison with In vivo Data in an Aortic Dissection

Vascular calcification results in stiffening of the aorta and is associated with hypertension and atherosclerosis. Atherogenesis is a complex, multifactorial, and systemic process; the result of a number of factors, each operating simultaneously at several spatial and temporal scales. The ability to predict sites of atherogenesis would be of great use to clinicians in order to improve diagnostic and treatment planning. In this paper, we present a mathematical model as a tool to understand why atherosclerotic plaque and calcifications occur in specific locations. This model is then used to analyze vascular calcification and atherosclerotic areas in an aortic dissection patient using a mechanistic, multi-scale modeling approach, coupling patient-specific, fluid-structure interaction simulations with a model of endothelial mechanotransduction. A number of hemodynamic factors based on state-of-the-art literature are used as inputs to the endothelial permeability model, in order to investigate plaque and calcification distributions, which are compared with clinical imaging data. A significantly improved correlation between elevated hydraulic conductivity or volume flux and the presence of calcification and plaques was achieved by using a shear index comprising both mean and oscillatory shear components (HOLMES) and a non-Newtonian viscosity model as inputs, as compared to widely used hemodynamic indicators. The proposed approach shows promise as a predictive tool. The improvements obtained using the combined biomechanical/biochemical modeling approach highlight the benefits of mechanistic modeling as a powerful tool to understand complex phenomena and provides insight into the relative importance of key hemodynamic parameters

EHop 167 Innovator Molecule Against Cancer

Cancer cells have a high activity of different proteins, among them Rac. Rac is from the Rho family of GTPases enzymes, which helps the cell invasion and migration. In order to study different strategies to decrease the high activity of this protein, we used EHop 167, a small molecule that helps to inhibit the activation of Rac. On this we can expose that EHop 167 can inhibits Rac activity and over expression with MDA-MB-231 breast cancer cell line derived from metastasis. If we used EHop 167 to treat breast cancer cells, then the Rac activity will be less and decrease cells invasion and migration. In the treatment we added to the cells a concentration of 2.5μM and 5μm of the molecule (EHop167) for a period of 24 hours. We also study other proteins such as Bad, BCL 2, BCL XL, Pak, and others, because they contribute to cancer by promoting growth and preventing apoptosis. Using different procedures such as Western Blot technique, an analytical technique used to detect specific proteins and their activity. The objective of this investigation is to prove that EHop 167 prevents the Rac activation in breast cancer cells. In overall, we pursue to develop a different method that could be effective against metastatic cancer

Estimating The Costs And Cost-effectiveness Of Promoting Mammography Screening Among US-based Latinas

Purpose: We characterize the costs and cost-effectiveness of a community health worker (CHW)-based intervention to promote screening mammography among US-based non-adherent Latinas. Methods: The parent study was a randomized controlled trial for 536 Latinas aged 42-74 years old who had sought care within a safety net health center in Western Washington. Participants were block-randomized within clinic to the control arm (usual care) or intervention arm (CHW-led motivational interviewing intervention). We used the perspective of the organization implementing promotional activities to characterize costs and cost-effectiveness. Cost data were categorized as program set-up and maintenance (initial training, booster/annual training) program implementation (administrative activities, intervention delivery); and, overhead/miscellaneous expenses. Cost-effectiveness was calculated as the incremental cost of screening for each additional woman screened between the intervention and control arms. Results: The respective costs per participant for standard care and the intervention arm were $69.96 and$300.99. There were no study arm differences in 1-year QALYs among women who completed a 12-month follow-up survey (intervention= 0.8827, standard care = 0.8841). Most costs pertained to program implementation and administrative activities specifically. The incremental cost per additional woman screened was $2,595.32. Conclusions: Our findings are within the ranges of costs and cost-effectiveness for other CHW programs to promote screening mammography among underserved populations. Our strong study design and focus on non-adherent women provides important strengths to this body of work, especially give implementation and dissemination science efforts regarding CHW-based health promotion for health disparity populations

Close encounters involving RAVE stars beyond the 47 Tucanae tidal radius

The most accurate 6D phase-space information from the Radial Velocity Experiment (RAVE) was used to integrate the orbits of 105 stars around the galactic globular cluster 47 Tucanae, to look for close encounters between them in the past, with a minimum distance approach less than the cluster tidal radius. The stars are currently over the distance range 3.0 kpc $<$ d $<$ 5.5 kpc. Using the uncertainties in the current position and velocity vector for both, star and cluster, 105 pairs of star-cluster orbits were generated in a Monte Carlo numerical scheme, integrated over 2 Gyr and considering an axisymmetric and non-axisymmetric Milky-Way-like Galactic potential, respectively. In this scheme, we identified 20 potential cluster members that had close encounters with the globular cluster 47 Tucanae, all of which have a relative velocity distribution (V$_{rel}$) less than 200 km s$^{-1}$ at the minimum distance approach. Among these potential members, 9 had close encounters with the cluster with velocities less than the escape velocity of 47 Tucanae, therefore a scenario of tidal stripping seems likely. These stars have been classified with a 93\% confidence level, leading to the identification of extratidal cluster stars. For the other 11 stars, V$_{rel}$ exceeds the escape velocity of the cluster, therefore they were likely ejected or are unassociated interlopers.Comment: 10 pages, 6 figures, 2 table, Accepted for publication in MNRA