A Preliminary Validation of a New Surgical Procedure for the Treatment of Primary Bladder Neck Obstruction Using a Computational Modeling Approach.

A new surgical procedure for the treatment of primary bladder neck obstruction with maintenance of anterograde ejaculation is proposed. In place of monolateral or bilateral bladder neck incision, associated with a loss of ejaculation rate of up to 30%, the new surgical procedure consists of laser drilling the bladder neck with a number of holes and without muscle fiber disruption. The effect of this novel procedure has been studied numerically, with a simplified two-dimensional numerical model of the internal urethral sphincter, varying the position and the number of holes in the fibrotic region of the urethral tissue. Results show an improvement of the urethral sphincter opening by increasing the number of holes, ranging from about 6% to 16% of recovery. Moreover, a non-aligned position of holes positively influences the opening recovery. The concentrations of maximum principal strain and stress have been registered in the proximity of the interface between the physiologic and diseased sphincter, and in those regions where the radial thickness is significantly thinner. The effects on the first five patients have been included in the study, showing improvement in micturition, lower urinary tract symptoms, sustained ejaculatory function, and quality of life.

Fluid dynamics in the functional foregut of xylem-sap feeding insects: A comparative study of two Xylella fastidiosa vectors.

Xylem sap sucking insects are adapted to ingest fluids under tension. Although much has been learned about such feeding strategy, this adaptation still poses several unresolved questions, including how these insects ingest against strong xylem sap tension. Xylem sap-feeding insects are vectors of the plant pathogenic xylem-limited bacterium Xylella fastidiosa. This bacterium colonizes the cuticular lining of the foregut of vectors in a persistent manner. We used micro-computed tomography and scanning electron microscopy to investigate the foregut morphometry of two X. fastidiosa vector species: Philaenus spumarius and Graphocephala atropunctata (Hemiptera: Aphrophoridae and Cicadellidae, respectively). On the basis of morphometric data, we built a hydrodynamic model of the foregut of these two insect species, focusing on the precibarium, a region previously shown to be colonized by X. fastidiosa and correlated with pathogen acquisition from and inoculation to plants. Our data show that space in the P. spumarius functional foregut could potentially harbor twice as many cells as similar space in G. atropunctata, although the opposite trend has been observed with biological samples. Average flow velocity of ingested fluid depended on the percentage of the cibarium volume exploited for suction: if the entire volume were used, velocities were in the range of meters per second. In contrast, velocities on the order of those found in the literature (about 10 cm/s) were attained if only 5% of the cibarium volume were exploited. Simulated bacterial colonization of the foregut was analyzed in relation to hydrodynamics and pressure needed for insects to ingest. Our model is designed to represent the diameter reduction of the food canal in both insect species when infected with X. fastidiosa. Results indicated that full bacterial colonization significantly increased the mean sap-sucking flow velocity. In particular, the colonization increased the maximum section-averaged velocity in the G. atropunctata more than two times and the net pressure needed to mantain the flow in the precibarium when colonized is relevant (about 0.151 MPa) if compared to a standard xylem sap tension (1 MPa). Bacterial colonization also influenced the sucking process of the G. atropunctata, by hindering the formation of a recirculation zone (or eddy), that characterizd the flow in the distal part of the precibarium when bacteria were absent. On the other hand, considering the pressure the insect must generate to feed, X. fastidiosa colonization probably influences fitness of the G. atropunctata more than that of P. spumarius.

Monitoring for Coastal Resilience: Preliminary Data from Five Italian Sandy Beaches.

Video-monitoring can be exploited as a valuable tool to acquire continuous, high-quality information on the evolution of beach morphology at a low cost and, on such basis, perform beach resilience analyses. This manuscript presents preliminary results of an ongoing, long-term monitoring programme of five sandy Italian beaches along the Adriatic and Tyrrhenian sea. The project aims at analyzing nearshore morphologic variabilities on a time period of several years, to link them to resilience indicators. The observations indicate that most of the beach width variations can be linked to discrete variations of sandbar systems, and most of all to an offshore migration and decay of the outermost bars. Further, the largest net shoreline displacements across the observation period are experienced by beaches with a clear NOM (Net Offshore Migration)-type evolution of the seabed.