Numerical Evaluation of Ventilation Performance in Children Day Care Centres

Modelling of ventilation is strongly dependent on the physical characteristics of the building of which precise evaluation is a complex and time consuming task. In the frame of a research project, two children day care centres (CDCC) have been selected in order to measure the envelope air permeability, the flow rate of mechanical ventilation systems and indoor and outdoor temperature. The data obtained was used as input to the computer code CONTAM for ventilation simulations. The results obtained were compared with direct measurements of ventilation flow from short term measurements with CO2 tracer gas and medium term measurements with perfluorocarbon tracer (PFT) gas decay method. After validation, in order to analyse the main parameters that affect ventilation, the model was used to predict the ventilation rates for a wide range of conditions. The purpose of this assessment was to find the best practices to improve natural ventilation. A simple analytical method to predict the ventilation flow rate of rooms is also presented. The method is based on the estimation of wind effect on the room through the evaluation of an average factor and on the assessment of relevant cross section of gaps and openings combined in series or in parallel. It is shown that it may be applied with acceptable accuracy for this type of buildings when ventilation is due essentially to wind action.

Unilateral Versus Bilateral Prostatic Arterial Embolization for Lower Urinary Tract Symptoms in Patients with Prostate Enlargement

PURPOSE: This study was designed to compare baseline data and clinical outcome between patients with prostate enlargement/benign prostatic hyperplasia (PE/BPH) who underwent unilateral and bilateral prostatic arterial embolization (PAE) for the relief of lower urinary tract symptoms (LUTS). METHODS: This single-center, ambispective cohort study compared 122 consecutive patients (mean age 66.7 years) with unilateral versus bilateral PAE from March 2009 to December 2011. Selective PAE was performed with 100- and 200-μm nonspherical polyvinyl alcohol (PVA) particles by a unilateral femoral approach. RESULTS: Bilateral PAE was performed in 103 (84.4 %) patients (group A). The remaining 19 (15.6 %) patients underwent unilateral PAE (group B). Mean follow-up time was 6.7 months in group A and 7.3 months in group B. Mean prostate volume, PSA, International prostate symptom score/quality of life (IPSS/QoL) and post-void residual volume (PVR) reduction, and peak flow rate (Qmax) improvement were 19.4 mL, 1.68 ng/mL, 11.8/2.0 points, 32.9 mL, and 3.9 mL/s in group A and 11.5 mL, 1.98 ng/mL, 8.9/1.4 points, 53.8 mL, and 4.58 mL/s in group B. Poor clinical outcome was observed in 24.3 % of patients from group A and 47.4 % from group B (p = 0.04). CONCLUSIONS: PAE is a safe and effective technique that can induce 48 % improvement in the IPSS score and a prostate volume reduction of 19 %, with good clinical outcome in up to 75 % of treated patients. Bilateral PAE seems to lead to better clinical results; however, up to 50 % of patients after unilateral PAE may have a good clinical outcome.