Mathematical modelling of the lower urinary tract

The lower urinary tract is one of the most complex biological systems of the human body as it involved hydrodynamic properties of urine and muscle. Moreover, its complexity is increased to be managed by voluntary and involuntary neural systems. In this paper, a mathematical model of the lower urinary tract it is proposed as a preliminary study to better understand its functioning. Furthermore, another goal of that mathematical model proposal is to provide a basis for developing artificial control systems. Lower urinary tract is comprised of two interacting systems: the mechanical system and the neural regulator. The latter has the function of controlling the mechanical system to perform the voiding process. The results of the tests reproduce experimental data with high degree of accuracy. Also, these results indicate that simulations not only with healthy patients but also of patients with dysfunctions with neurological etiology present urodynamic curves very similar to those obtained in clinical studies.

Mercury determination in urine samples by gold nanostructured screen-printed carbon electrodes after vortex-assisted ionic liquid dispersive liquid–liquid microextraction

A novel approach is presented to determine mercury in urine samples, employing vortex-assisted ionic liquid dispersive liquid–liquid microextraction and microvolume back-extraction to prepare samples, and screen-printed electrodes modified with gold nanoparticles for voltammetric analysis. Mercury was extracted directly from non-digested urine samples in a water-immiscible ionic liquid, being back-extracted into an acidic aqueous solution. Subsequently, it was determined using gold nanoparticle-modified screen-printed electrodes. Under optimized microextraction conditions, standard addition calibration was applied to urine samples containing 5, 10 and 15 μg L−1 of mercury. Standard addition calibration curves using standards between 0 and 20 μg L−1 gave a high level of linearity with correlation coefficients ranging from 0.990 to 0.999 (N = 5). The limit of detection was empirical and statistically evaluated, obtaining values that ranged from 0.5 to 1.5 μg L−1, and from 1.1 to 1.3 μg L−1, respectively, which are significantly lower than the threshold level established by the World Health Organization for normal mercury content in urine (i.e., 10–20 μg L−1). A certified reference material (REC-8848/Level II) was analyzed to assess method accuracy finding 87% and 3 μg L−1 as the recovery (trueness) and standard deviation values, respectively. Finally, the method was used to analyze spiked urine samples, obtaining good agreement between spiked and found concentrations (recovery ranged from 97 to 100%).

Status and quality of radiation measurements : food and human urine /

Issued Oct. 1977.

Analyses of airborne particulates and human urine by inductively coupled plasma-atomic emission spectrometry /

October 1978.

The evolution of urine analysis : an historical sketch of the clinical examination of urine: lecture memoranda, American Medical Association, Los Angeles, 1911.

Foreword signed: Henry S. Wellcome.

An expendable cage to separate the urine and feces of rats in tracer experiments /

"Contract No. At-40-1-Gen-33."

Traité des rétentions d'urine causées par le rétrécissement de l'urètre ... /

Mode of access: Internet.

Traité pratique des maladies des organes génito-urinaires : précédé de l'étude chimique et physique des changements que l'urine éprouve pendant les maladies et des indications qui en résultent au point de vue du diagnostic et du traitement /

Mode of access: Internet.

Traité des parties qui servent de passage a l'urine, avec leur description, leur action & leurs usages : dans lequel on deduit les principales maladies qui affectent ces parties /

Mode of access: Internet.

Recueil de pieces importantes sur l'operation de la taille, faite par le lithotome cache : avec un memoire concernant la retention d'urine, causée par l'embarras du canal de l'uretre.

Mode of access: Internet.

Traité des rétentions d'urine causées par le rétrécissement de l'urètre ... /

Mode of access: Internet.