Assessment of refrigerant mixtures performance with thermal glide for cold climate air-source heat pumps

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Heat pumps are currently considered as one of the most promising means for meeting low energy consumption requirements in buildings. However conventional air source heat pumps suffer from severe limitations in terms of performance at low ambient temperatures, while new designs such as multi-stage compression or ground source heat pumps are still very costly. The main challenge is to improve on the air-source heat pumps low efficiency in cold climates at a reasonable cost. The use of mixtures of refrigerants with the aim of increasing heat pumps performance (COP and/or heating capacity) by taking advantage of the thermal glide has been so far, little studied for the heating and cooling of buildings. In this paper, the goal is to assess the performance of refrigerant mixtures with thermal glide for cold climate air-source heat pumps. A simple theoretical and an extended model have been developed and used for refrigerant mixtures performance evaluation. It is shown that a good potential exists in refrigerant mixtures with moderate glide to improve the performance of cold climate air-source heat pumps.cf201

MRI in active surveillance: a critical review

INTRODUCTION: Recent technological advancements and the introduction of modern anatomical and functional sequences have led to a growing role for multiparametric magnetic resonance imaging (mpMRI) in the detection, risk assessment and monitoring of early prostate cancer. This includes men who have been diagnosed with lower-risk prostate cancer and are looking at the option of active surveillance (AS). The purpose of this paper is to review the recent evidence supporting the use of mpMRI at different time points in AS, as well as to discuss some of its potential pitfalls. METHODS: A combination of electronic and manual searching methods were used to identify recent, important papers investigating the role of mpMRI in AS. RESULTS: The high negative predictive value of mpMRI can be exploited for the selection of AS candidates. In addition, mpMRI can be efficiently used to detect higher risk disease in patients already on surveillance. CONCLUSION: Although there is an ongoing debate regarding the precise nature of its optimal implementation, mpMRI is a promising risk stratification tool and should be considered for men on AS

Rôle de l’IRM prostatique dans le cancer de la prostate en 2016: mise au point et perspectives d’avenir

RésuméLe diagnostic du cancer de la prostate est le plus souvent porté à l’occasion d’un dosage élevé de PSA, fait dans le cadre du dépistage individuel, et repose sur la réalisation de «biopsies systématisées» par voie transrectale avec guidage échographique. Cette stratégie classique entraîne un risque de sur-diagnostic de cancers cliniquement non significatifs [microfoyers], ainsi qu’une non-détection de certains cancers cliniquement significatifs situés en dehors des zones prélevées. La réalisation d’une IRM prostatique avant les biopsies a tout changé. Elle augmente la détection des cancers de volume significatif grâce aux «biopsies ciblées» sur les anomalies vues à l’IRM. Elle améliore l’estimation de leur grade, de leur taille et permet de préciser leur localisation et contour. Elle permettrait aussi de diminuer la détection des cancers non significatifs, si les biopsies systématisées n’étaient plus faites en cas d’IRM sans cible suspecte. Les applications thérapeutiques de l’IRM sont déterminantes pour l’essor des options récentes de prise en charge comme la sélection des patients pour la surveillance active ainsi que pour l’indication de traitement focal. Les modalités de réalisation et d’interprétation de l’IRM ont été publiées en 2016 sous forme d’une mise à jour du score PI-RADS [Prostate Imaging Reporting and Data System version 2]. Cette standardisation aide les radiologues à proposer aux cliniciens urologues et radiothérapeutes les éléments nécessaires pour le diagnostic et le traitement des cancers de la prostate.AbstractProstate cancer is most commonly diagnosed on the basis of an increased serum prostate specific antigen (PSA) level, through individual screening, and is carried out following systematic transrectal ultrasound-guided prostate biopsies. This strategy is associated with risks of overdiagnosing clinically non significant cancers, as well as missing clinically significant ones. Performing a prostate magentic resonance imaging (MRI) prior to prostate biopsies modifies the way of diagnosing prostate cancer. It increases the detection rate of clinically significant cancers by using targeted biopsies focused on lesions that are detected on MRI. It enhances the estimation of grade, size, location and boundaries of the lesions. It may be used to reduce the detection rate of clinically non significant cancers if the systemic biopsies were not performed in patients without any suspect MRI lesion. Therapeutic use of MRI includes screening of patients eligible for active surveillance or focal treatment. MRI protocols and interpretation have been published in 2016 as an update of the PI-RADS score (Prostate Imaging Reporting and Data System version 2). Standardising the acquisition, interpretation and reporting of prostate MRI is useful for urologists and radiation oncologists in order to diagnose and treat prostate cancer

Prostate cancer: Diagnosis, parametric imaging and standardized report

AbstractMultiparametric MR of the prostate provides an extremely accurate diagnosis and offers an excellent negative predictive value for cancers which biopsies struggle to detect. Combined with biopsies they consolidate both positive and negative biopsy results and allow patients to be offered more appropriate treatments (active monitoring, radical treatment in full knowledge of the topography of the lesions involved, or local treatment, etc.). The investigation does not require advanced equipment and can be carried out in any MR centre although it needs to follow a technical protocol described in the European guidelines (ESUR 2012). Interpretation should be standardized to facilitate communication of clear and consistent information between practitioners