Functional Anatomy of the Female Pelvic Floor

The anatomic structures in the female that prevent incontinence and genital organ prolapse on increases in abdominal pressure during daily activities include sphincteric and supportive systems. In the urethra, the action of the vesical neck and urethral sphincteric mechanisms maintains urethral closure pressure above bladder pressure. Decreases in the number of striated muscle fibers of the sphincter occur with age and parity. A supportive hammock under the urethra and vesical neck provides a firm backstop against which the urethra is compressed during increases in abdominal pressure to maintain urethral closure pressures above the rapidly increasing bladder pressure. This supporting layer consists of the anterior vaginal wall and the connective tissue that attaches it to the pelvic bones through the pubovaginal portion of the levator ani muscle, and the uterosacral and cardinal ligaments comprising the tendinous arch of the pelvic fascia. At rest the levator ani maintains closure of the urogenital hiatus. They are additionally recruited to maintain hiatal closure in the face of inertial loads related to visceral accelerations as well as abdominal pressurization in daily activities involving recruitment of the abdominal wall musculature and diaphragm. Vaginal birth is associated with an increased risk of levator ani defects, as well as genital organ prolapse and urinary incontinence. Computer models indicate that vaginal birth places the levator ani under tissue stretch ratios of up to 3.3 and the pudendal nerve under strains of up to 33%, respectively. Research is needed to better identify the pathomechanics of these conditions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72597/1/annals.1389.034.pd

Surgery for Urinary Incontinence in Women

This chapter is intended to present a further assessment of surgical interventions for urinary incontinence in women. The intent of this chapter is o build upon data that were previously collated for the ICUD Report of 2009. This chapter updates the current status of surgical interventions for stress urinary incontinence and includes additional data that have been forthcoming regarding new interventions (such as transobturator tapes and single incision slings).The further enhancement on sections related to clinical research and specific outcomes reporting on clinical trial design has been updated with experience from recently reported multi-institutional trials which assess surgical interventions for incontinence.<br/

Controlling PbI2 stoichiometry during synthesis to improve the performance of perovskite photovoltaics

Over the past decade, remarkable progress has advanced the field of perovskite solar cells to the forefront of thin film solar technologies. The stoichiometry of the perovskite material is of paramount importance as it determines the optoelectronic properties of the absorber and hence the device performance. However, little published work has focused on the synthesis of fully stoichiometric precursor materials of high purity and at high yield. Here, we report a low-cost, energy-efficient, and solvent-free synthesis of the lead iodide precursor by planetary ball milling. With our synthetic approach, we produce low-oxygen, single or multiple polytypic phase PbI2 with tunable stoichiometry. We determine the stoichiometry and the polytypes present in our synthesized materials and further compare them to commercially available materials, using X-ray diffraction, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. Both the stoichiometric PbI2 we synthesized and a substoichiometric commercially available PbI2 (where the iodide content is below the optimum Pb:I atomic ratio of 1:2) were used to grow methylammonium lead iodide microcrystals (which corrects the iodide content). Perovskite solar cells were then produced using stoichiometric and substoichiometric PbI2 mixed with an equimolar amount of methylammonium iodide and compared to devices produced from re-dissolved microcrystals. The photoactive perovskite layer deposition was processed in air, enabled by the use of a single low-toxicity solvent (dimethyl sulfoxide) combined with vacuum-assisted solvent evaporation. We find that the device performance is strongly dependent upon the stoichiometry of the lead iodide precursor, reaching champion efficiencies over 17%, with no obvious correlation with its polytypic phases. This work highlights the critical role of PbI2 stoichiometry in hybrid perovskites as well as demonstrating synthesis methods and perovskite layer fabrication protocols suitable for low-cost solar energy harvesting

Anatomical and functional changes in the lower urinary tract during pregnancy

Objective To assess the prevalence and the development of urinary incontinence in nulliparous pregnant women, both subjectively and objectively, and to investigate the relation of incontinence with the mobility of the urethro-vesical junction measured by perineal ultrasound. Design A prospective longitudinal study. Setting University Hospital and Martini Hospital Groningen, the Netherlands. Population A cohort of 117 nulliparous pregnant women and 27 nulliparous non-pregnant controls. Methods Urinary incontinence was measured by a questionnaire and by a 24-hour pad test. The position of the urethro-vesical junction and its mobility were measured by perineal ultrasound. Main outcome measure Prevalence of urinary incontinence; mobility of the urethro-vesical junction, indicated by the displacement/pressure coefficient. Results Up to 35% of the women reported urinary incontinence in pregnancy, and 20% of the women had a positive pad test. The angle of the urethro-vesical junction angle at rest and the displacement/pressure coefficient during coughing showed a significant increasing trend during pregnancy, but no changes were seen during the Valsalva manoeuvre. No relationship was found between subjective and objective incontinence data and the position and mobility of the urethro-vesical junction. Conclusion The prevalence of incontinence in nulliparous women as found by the pad test was significantly higher in pregnancy (20%) than in the non-pregnant control group (4%). Perineal ultrasound of the urethrovesical junction showed lowering of the pelvic floor occurring as early as 12-16 weeks of pregnancy. Serial measurements of the displacement/pressure coefficient suggest that the dynamic characteristics of the connective tissues of the pelvic floor remain unaltered,whereas a significant decrease in pelvic floor muscle contraction occurs. Since no relation was found between measurements of the urethro-vesical junction and incontinence, urinary incontinence in pregnancy is most likely explained by other factors