A Velocity-Based Approach to Noninvasive Methodology for Urodynamic Analysis.

PURPOSE: To date, invasive urodynamic investigations have been used to define most terms and conditions relating to lower urinary tract symptoms. This invasiveness is almost totally due to the urethral catheter. In order to remove this source of discomfort for patients, the present study investigated a noninvasive methodology able to provide diagnostic information on bladder outlet obstruction or detrusor underactivity without any contact with the human body. METHODS: The proposed approach is based on simultaneous measurements of flow rate and jet exit velocity. In particular, the jet exit kinetic energy appears to be strongly related to bladder pressure, providing useful information on the lower urinary tract functionality. We developed a new experimental apparatus to simulate the male lower urinary tract, thus allowing extensive laboratory activities. A large amount of data was collected regarding different functional statuses. RESULTS: Experimental results were compared successfully with data in the literature in terms of peak flow rate and jet exit velocity. A new diagram based on the kinetic energy of the exit jet is proposed herein. Using the same notation as a Schäfer diagram, it is possible to perform noninvasive urodynamic studies. CONCLUSION: A new noninvasive approach based on the measurement of jet exit kinetic energy has been proposed to replace current invasive urodynamic studies. A preliminary assessment of this approach was carried out in healthy men, with a specificity of 91.5%. An additional comparison using a small sample of available pressure-flow studies also confirmed the validity of the proposed approach.

Microplastics in the Florence wastewater treatment plant studied by a continuous sampling method and Raman spectroscopy: A preliminary investigation.

The presence of an ever increasing amount of plastic in the Italian river system makes it necessary to understand the contribution of their different sources. We focus on the contribution from the wastewater treatment plants to the microplastics (MPs), size less than 5 mm, conveyed to the fluvial system, and on the development of methods for their detection in this matrix. This study, one of the first in Italy, is aimed to investigate the content of MPs present in the effluent of the main wastewater treatment plant in Florence (Italy). We sampled wastewater during dry season to mainly quantify the contribution from civil and municipal activities to the MPs release. The samples were continuously collected over a period of 24 h at the exit of the water line using a series of 8 sieves with different mesh sizes (almost 1000 L filtered volume). The sampled material was analyzed by optical microscopy and micro-Raman spectroscopy by use of low-cost, portable instruments. The spatial resolution of the spectrometer matches the minimum dimension of the mesh size in use (38 µm). The analysis detected an average concentration of 5 MPs per liter in the 38-1000 µm diameter range, corresponding to a daily release of about 35 kg/day into the River Arno, a result in line with other studies carried out on Europe's major rivers. We provide a classification of the polymer composition showing the predominant presence of Polypropylene (29%), Polyethylene (18%) and Polyester (14%). The MP shape classification reveals the relevance of fibers in effluents. The number of sieves used provided an accurate size distribution curve of the sampled MPs allowing to estimate, by extrapolation, a relevant quantity of MPs finer than 38 µm whose determination would otherwise require much more sophisticated methods.

On the prediction of settling velocity for plastic particles of different shapes.

Transport processes of plastic particles in freshwater and marine environments are one of the relevant advances of knowledge in predicting the fate of plastic in the environment. Here, we investigated the effect of different shapes on the settling velocity, finding a representative reference diameter which encompasses three-dimensional shapes like pellets or spherules, two-dimensional shapes like fragments or disks, and one-dimensional shapes like filaments or fibers. The new method is able to predict the settling velocity of plastic and natural particles given the representative size and the Corey shape factor coefficient, over the entire range of viscous to turbulent flow regime. The calibration of the method with experimental data, and the validation with an independent dataset, support its application in a wide range of hydraulic conditions.