We present in this proceeding recent large scale simulations of dense colloids. On one hand we simulate model clay consisting of nanometric aluminum oxyde spheres in water using realistic effective electrostatic interactions and Van der Waals attractions, known as DLVO potentials and a combination of molecular dynamics (MD) and stochastic rotation dynamics (SRD). We find pronounced cluster formation and retrieve the shear softening of the viscosity in quantitative agreement with experiments. On the other hand we study the velocity probability distribution functions (PDF) of sheared hard-sphere colloids using a combination of MD with lattice Boltzmann and find strong deviations from a Maxwell-Boltzmann distribution. We find a Gaussian core and an exponential tail over more than six orders of magnitude of probability. The simulation data follow very well a simple theory. We show that the PDFs scale with shear rate $\dot\gamma$ as well as particle volume concentration phi, and kinematic viscosity nu.

Dense packings of granular systems are of fundamental importance in the manufacture of hard ceramics and ultra strong concrete. We generalize the reversible parking lot model to describe polydisperse dynamic packings. The key ingredient lies in the size distribution of grains. In the extreme case of perfect filling of spherical beads (density one), one has Apollonian tilings with a powerlaw distribution of sizes. We will present the recent discovery of 3D packings which also have the freedom to rotate (bearings) in three dimensions.

INTRODUCTION: SAFYRE is a new readjustable and minimally invasive sling for the treatment of stress urinary incontinence (SUI). Attempts to restore the normal suburethral hammock using an anatomical approach have been made in recent years. The authors report their experience with this device, which associates the efficacy of slings with readjustability. MATERIAL AND METHODS: A total of 100 consecutive patients with clinical and urodynamic diagnosis of SUI underwent SAFYRE sling procedure. The age range was from 40 to 71, mean age 63 years. Seventy-five patients (75%) presented previous failed anti-incontinence procedures. Physical clinical examination, stress test, pad use and a urodynamic study were performed before the surgery. All the patients presented symptoms of SUI and 30 % also reported mild urgency. RESULTS: The average follow up period was 14 months (12 - 30 months). The mean operative time was of 25 minutes. Dystopia repair was performed whenever necessary, during the same procedure. The average hospital stay was 24 hours. In 3% of the implants, bladder perforation occurred. During the postoperative period, 26 patients developed urgency symptoms. During that follow up period, 92% were found to be continent, 3% reported an improvement and 5% were dissatisfied. CONCLUSION: SAFYRE is a safe and quick procedure that allows for postoperative readjustment. This technique may be an attractive alternative if the good result obtained so far proves to be long lasting.

INTRODUCCIÓN: SAFYRE es un nuevo cabestrillo (dispositivo de suspensión) reajustable y mínimamente invasivo para el tratamiento de la incontinencia urinaria por estrés (IUE). En los últimos años se ha intentado restaurar el lecho suburetral normal utilizando una técnica anatómica. Los autores comunican su experiencia con este dispositivo, que además de poseer la eficacia de los cabestrillos tiene capacidad de reajustación. MATERIALES y MÉTODOS: Un total de 100 pacientes consecutivas con diagnóstico de IUE desde el punto de vista clínico y urodinámico se sometieron al procedimiento de implantación del cabestrillo SAFYRE. Su rango de edad era de 40 a 71 años, con una edad media de 63 años. Previamente, 75 pacientes (75%) se habían sometido a procedimientos para la incontinencia que habían fracasado. Antes de la cirugía se realizaron una exploración física clínica, una prueba de estrés, un estudio urodinámico y un estudio sobre el uso de almohadillas. Todas las pacientes presentaban síntomas de IUE y el 30% también tenían tenesmo leve. RESULTADOS: El periodo de seguimiento medio fue de 14 meses (12 - 30 meses). El tiempo medio de la operación fue de 25 minutos. Durante el mismo procedimiento se reparó la distopia cuando se consideró necesario. La estancia hospitalaria media fue de 24 horas. En el 3% de los implantes se produjo perforación de la vejiga. Durante el periodo posoperatorio 26 pacientes presentaron síntomas de tenesmo. Durante ese periodo de seguimiento, el 92% presentaron continencia urinaria, el 3% mejoraron y el 5% no estuvieron satisfechas con el procedimiento. CONCLUSIÓN: SAFYRE es un procedimiento seguro y rápido que permite el reajuste posoperatorio. Esta técnica puede ser una alternativa atractiva si se demuestra que los buenos resultados obtenidos hasta ahora son de larga duración.