Molecular insights on NaCl crystal formation approaching PVDF membranes functionalized with graphene.

Membrane-assisted crystallization is an emerging technology where microporous hydrophobic membranes are used not as selective barriers but to promote the water vapor transfer between phases inducing supersaturation in solution. This has been successfully tested in the crystallization of ionic salts, low molecular weight organic acids and proteins. In this work, molecular dynamics simulations were used to study the crystal nucleation and growth of sodium chloride in contact with hydrophobic polymer surfaces at a supersaturated concentration of salt. A pristine polyvinylidene fluoride (PVDF) surface and PVDF containing different concentrations of graphene platelets were studied. Membrane crystallization tests were performed in parallel, in order to compare the experimental results with the computational ones. Here, with an integrated experimental-computational approach, we demonstrate that graphene-containing membranes assisted the crystal growth of NaCl, speeding up crystal nucleation in comparison with the pristine PVDF membranes. The computational results agreed with the experimental data, allowing the possibility of exploring the behavior of nanomaterials in membrane processes at a microscopic level.

Relapsed papillary urothelial neoplasm of low malignant potential (PUNLMP) of the young age: a case report and a review of the literature.

BACKGROUND: Papillary Urothelial Neoplasm of Low Malignant Potential (PUNLMP) are exceptionally rare in the first decade of life (mostly if multifocal) and there is a lack of standardized recommendations for the pediatric age. CASE PRESENTATION: We describe the case of a 9-year-old boy with a diagnosis of PUNLMP, who underwent to cystoscopic lesion removal and later to endoscopic lesion removal and intra-bladder Mitomycin-c (MMC) instillations for relapsed disease. Follow-up investigations at five years showed disease negativity. CONCLUSIONS: Intra-bladder MMC instillation may allow obtaining the complete remission with bladder-sparing for paediatric patients with a high-risk relapsed PUNLMP.

Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes.

This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

The fate of prenatally diagnosed primary nonrefluxing megaureter: do we have reliable predictors for spontaneous resolution?

OBJECTIVES: To compare predictive values of current morphologic parameters with congenital renal damage associated with severe megaureter. METHODS: A retrospective analysis was performed using records of 37 patients (50 megaureters) referred before birth for a primary megaureter. Mean follow-up was 26 months (range, 1 to 8 years). RESULTS: Dilatation resolved spontaneously in 46 of 50 ureters. Only 4 of 37 patients required surgery (10.8%) after a mean follow-up of 58 months (range, 32 to 80 months). Average time to resolution was 24 months (range, 1 to 82 months) and was independent from sex, side, and bilaterality. A weak correlation was found with initial anteroposterior pelvic diameter, ureteral diameter, and separate function at renogram. A significant correlation (P <0.02) was found between megaureter type and time elapsed to spontaneous resolution. As far as differential function was concerned, mean values were significantly lower among type III megaureters, which had the lowest rate of resolution. CONCLUSIONS: The fate of severe megaureter seems strongly influenced by congenital renal damage secondary to a developmental abnormality of the ureteric bud. A poor resolution rate has to be expected in these cases; surgery must be reserved for symptomatic cases but has no influence on pre-existing renal damage.