Investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic artificial model

Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an artificial model of the ureter (i.e. ureter model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q ) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM

On-Treatment Platelet Reactivity is a Predictor of Adverse Events in Peripheral Artery Disease Patients Undergoing Percutaneous Angioplasty

Objectives: Few data are available on the association between a different entity of platelet inhibition on antiplatelet treatment and clinical outcomes in patients with peripheral artery disease (PAD). The aim of this study was to evaluate the degree of on-treatment platelet reactivity, and its association with ischaemic and haemorrhagic adverse events at follow up in PAD patients undergoing percutaneous transluminal angioplasty (PTA). Methods: In this observational, prospective, single centre study, 177 consecutive patients with PAD undergoing PTA were enrolled, and treated with dual antiplatelet therapy with aspirin and a P2Y12 inhibitor. Platelet function was assessed on blood samples obtained within 24 h from PTA by light transmission aggregometry (LTA) using arachidonic acid (AA) and adenosine diphosphate (ADP) as agonists of platelet aggregation. High on-treatment platelet reactivity (HPR) was defined by LTA ≥ 20% if induced by AA, and LTA ≥ 70% if induced by ADP. Follow up was performed to record outcomes (death, major amputation, target vessel re-intervention, acute myocardial infarction and/or myocardial revascularisation, stroke/TIA, and bleeding). Results: HPR by AA and HPR by ADP were found in 45% and 32% of patients, respectively. During follow up (median duration 23 months) 23 deaths (13%) were recorded; 27 patients (17.5%) underwent target limb revascularisation (TLR), two (1.3%) amputation, and six (3.9%) myocardial revascularisation. Twenty-four patients (15.6%) experienced minor bleeding. On multivariable analysis, HPR by AA and HPR by ADP were independent predictors of death [HR 3.8 (1.2–11.7), p =.023 and HR 4.8 (1.6–14.5), p =.006, respectively]. The median value of LTA by ADP was significantly lower in patients with bleeding complications than in those without [26.5% (22–39.2) vs. 62% (44.5–74), p <.001). LTA by ADP ≤ 41% was independently associated with bleeding HR 14.6 (2.6–24.0), p =.001] on multivariable analysis. Conclusions: In this study a high prevalence of on-clopidogrel and aspirin high platelet reactivity was found, which was significantly associated with the risk of death. Conversely, a low on-clopidogrel platelet reactivity was associated with a higher risk of bleeding. These results document that the entity of platelet inhibition is associated with both thrombotic and bleeding complications in PAD patients

Joint registration and segmentation via multi-task learning for adaptive radiotherapy of prostate cancer

Medical image registration and segmentation are two of the most frequent tasks in medical image analysis. As these tasks are complementary and correlated, it would be beneficial to apply them simultaneously in a joint manner. In this paper, we formulate registration and segmentation as a joint problem via a Multi-Task Learning (MTL) setting, allowing these tasks to leverage their strengths and mitigate their weaknesses through the sharing of beneficial information. We propose to merge these tasks not only on the loss level, but on the architectural level as well. We studied this approach in the context of adaptive image-guided radiotherapy for prostate cancer, where planning and follow-up CT images as well as their corresponding contours are available for training. At testing time the contours of the follow-up scans are not available, which is a common scenario in adaptive radiotherapy. The study involves two datasets from different manufacturers and institutes. The first dataset was divided into training (12 patients) and validation (6 patients), and was used to optimize and validate the methodology, while the second dataset (14 patients) was used as an independent test set. We carried out an extensive quantitative comparison between the quality of the automatically generated contours from different network architectures as well as loss weighting methods. Moreover, we evaluated the quality of the generated deformation vector field (DVF). We show that MTL algorithms outperform their Single-Task Learning (STL) counterparts and achieve better generalization on the independent test set. The best algorithm achieved a mean surface distance of 1.06 +/- 0.3 mm, 1.27 +/- 0.4 mm, 0.91 +/- 0.4 mm, and 1.76 +/- 0.8 mm on the validation set for the prostate, seminal vesicles, bladder, and rectum, respectively. The high accuracy of the proposed method combined with the fast inference speed, makes it a promising method for automatic re-contouring of follow-up scans for adaptive radiotherapy, potentially reducing treatment related complications and therefore improving patients quality-of-life after treatment. The source code is available at https://github.com/moelmahdy/JRS-MTL.Biological, physical and clinical aspects of cancer treatment with ionising radiatio

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Assessment of energy rating of polyurethane spray foam walls: procedure and interim results

The focus of this paper will be on presenting a brief summary of project objective, testnig protocol and the theoretical approach to determine the WER for the six walls. In addition, the test procedures and experimental results (air leakage and R-value), wall samples construction of a number of walls and a sample of the analytical results are presented. Future publications will cover the more details about the analytical and computer simulation to determine WER.Ce document aura pour but particulier de pr\ue9senter un court r\ue9sum\ue9 de l?objectif du projet, le protocole d?essai suivi et l?approche th\ue9orique adopt\ue9e en vue de d\ue9terminer la cote \ue9nerg\ue9tique des murs (C\uc9M) pour les six (6) murs. Sont expos\ue9s \ue9galement les proc\ue9dures d?essai et les r\ue9sultats exp\ue9rimentaux (fuites d?air et valeur \uab R \ubb), la construction des \ue9chantillons de plusieurs murs diff\ue9rents, ainsi qu?un \ue9chantillonnage des r\ue9sultats analytiques. De futures publications couvriront plus en d\ue9tail la simulation informatique et analytique pour la d\ue9termination de la C\uc9M.Peer reviewed: YesNRC publication: Ye

Field Assessment of the Thermal Characteristics of Innovative Glazing Systems at the Canadian Centre for Housing Technology

The energy consumption of twin research houses was compared for high solar heat gain (HSG) and low solar heat gain (LSG) glazing systems. The glazing systems were compared for 28 days during the winter and 23 days during the summer. During these periods, all 31 glazing units in the test house were fitted with LSG glazing and compared to 31 HSG glazed windows in the reference house. The impact of the glazing on solar gains, heating and air conditioning energy consumption, window surface temperatures and room temperatures was monitored. RESFEN, HOT2000 and ESPr computer simulation was used to compare the field trial and modeling results.On a compar\ue9 la consommation \ue9nerg\ue9tique des syst\ue8mes de vitrage \ue0 apport par rayonnement solaire \ue9lev\ue9 (ARS\uc9) et \ue0 apport par rayonnement solaire faible (ARSF) install\ue9s sur des maisons de recherche jumel\ue9es. Les syst\ue8mes de vitrage ont \ue9t\ue9 compar\ue9s pendant 28 jours en hiver et 23 jours en \ue9t\ue9. Durant ces p\ue9riodes, tous les 31 carreaux de la maison d'essai ont \ue9t\ue9 dot\ue9s de vitrage ARSF et compar\ue9s aux 31 fen\ueatres \ue0 vitrage ARS\uc9 de la maison jumelle t\ue9moin. L'incidence du vitrage sur les valeurs d'apport par rayonnement solaire, la consommation d'\ue9nergie par le chauffage et la climatisation, les temp\ue9ratures \ue0 la surface des fen\ueatres et les temp\ue9ratures ambiantes a \ue9t\ue9 surveill\ue9e. On a utilis\ue9 la simulation par ordinateur RESFEN, HOT2000 et ESPr pour comparer les r\ue9sultats des essais in situ et ceux de la mod\ue9lisation.Peer reviewed: NoNRC publication: Ye

Workshop on Moisture Management and Energy Rating in Building Envelopes / Part III : Assessment of Energy Rating of Polyurethane Foam Walls - Procedure and Interim results

Conference Organization by NRC-IRC staffPeer reviewed: NoNRC publication: Ye

Energy rating of polyurethane spray foamed walls: procedures and preliminary results

This is the first of a series of papers to present the results of this major project. In this paper, an overview of the project, its objectives and the theoretical approach to determine the WER are presented. A description of air leakage and R-value test procedures, wall samples construction and the experimental results of two walls and a sample of the analytical results of the same two walls will also be presented. Future papers will summa-rise the experimental and analytical results of the remaining walls, along with the results of the computer modeling of the air leakage and thermal performance of all the walls tested in this project.Ceci est le premier d?une s\ue9rie de documents dans lesquels sont pr\ue9sent\ue9s les r\ue9sultats de ce projet d?envergure. Dans ce document, on donne une vue d?ensemble du projet, de ses objectifs et de l?approche th\ue9orique qui est adopt\ue9e dans le but de d\ue9terminer la cote \ue9nerg\ue9tique globale. Sont offerts \ue9galement une description des m\ue9thodes d?essai d?\ue9tanch\ue9it\ue9 \ue0 l?air et de valeur \uab R \ubb, de la construction des \ue9chantillons de mur et des r\ue9sultats exp\ue9rimentaux obtenus avec deux (2) murs, ainsi qu?un exemple des r\ue9sultats analytiques de ces m\ueames deux murs. Les documents \ue0 venir r\ue9sumeront les r\ue9sultats exp\ue9rimentaux et analytiques des autres murs, de m\ueame que ceux de la mod\ue9lisation de la performance en termes d?\ue9tanch\ue9it\ue9 \ue0 l?air et d?isolation thermique de tous les murs mis \ue0 l?essai dans le cadre de ce projet.Peer reviewed: YesNRC publication: Ye

Numerical simulations for determining the thermal response of wall systems with medium density polyurethane spray foams

Using Polyurethane Spray Foams (SPFs) as insulation in buildings provide durable and efficient thermal barriers. The industry is encouraging the SPF as an effective air barrier system in addition to its thermal insulation characteristics. In an effort to address these issues, a consortium of SPF manufacturers and contractors, jointly with the National Research Council of Canada?s Institute for Research in Construction, (NRC-IRC) conducted an extensive research project to assess the thermal and air leakage characteristics of SPF walls.L?utilisation de la mousse de polyur\ue9thane pulv\ue9ris\ue9e (MPP) comme isolant dans les b\ue2timents procure des \ue9crans thermiques \ue0 la fois durables et efficaces. L?industrie pr\ue9conise l?emploi de la MPP non seulement comme syst\ue8me pare-air efficace, mais aussi en raison de ses caract\ue9ristiques d?isolation thermique. C?est dans le but de r\ue9pondre \ue0 ces pr\ue9occupations qu?un consortium de fabricants de MPP et d?entrepreneurs en isolation \ue0 base de MPP, conjointement avec l?Institut de recherche en construction du Conseil national de recherches du Canada (IRC-CNRC), a dirig\ue9 un projet de recherche exhaustif visant l?\ue9valuation des caract\ue9ristiques thermiques et de r\ue9sistance aux fuites d?air des murs isol\ue9s \ue0 la MPP.Peer reviewed: YesNRC publication: Ye