Optimization of an Optical Test Bench for Tire Properties Measurement and Tread Defects Characterization.

Tire characteristics and behavior are of great importance in vehicle dynamics since the forces transmitted in the tire-road contact are the main contributors to global vehicle performance. Several research groups have focused on the study and modeling of tires. Some of the most important factors that need to be known are tread characteristics and pressure distribution in the tire-ground contact patch. In this work, a test bench has been used to adequately determine the aforementioned factors. The measurement principle of the test bench is the frustration of total internal reflection (FTIR) of light. It makes use of a laterally illuminated glass on which the tire leans. An interposed plastic interface between them causes the reflection of light. Finally, a video camera captures the bright image formed through the glass. The brightness level in each pixel of the image is related to existing normal pressure. A study of the parameters that affect the test bench calibration such as type of interface material used, diffuse light, hysteresis, creep and transverse light absorption is performed. Experimental tests are conducted to relate tire inflation pressure and camber angle to the pressure distribution. Furthermore, the test bench is used to detect and evaluate the influence of defects in the tire on the contact pressures.

L4 fixation is not necessary in L5-Iliac spinopelvic fixation after trauma, but coadjutant transilio-transsacral fixation is.

INTRODUCTION: Spinopelvic dissociation (SPD) is a severe injury characterized by a discontinuity between the spine and the bony pelvis consisting of a bilateral longitudinal sacral fracture, most of the times through sacral neuroforamen, and a horizontal fracture, usually through the S1 or S2 body. The introduction of the concept of triangular osteosynthesis has shown to be an advance in the stability of spinopelvic fixation (SPF). However, a controversy exists as to whether the spinal fixation should reach up to L4 and, if so, it should be combined with transiliac-transsacral screws (TTS). OBJECTIVE: The purpose of this study is to compare the biomechanical behavior in the laboratory of four different osteosynthesis constructs for SPD, including spinopelvic fixation of L5 versus L4 and L5; along with or without TTS in both cases. MATERIAL AND METHODS: By means of a formerly described method by the authors, an unstable standardized H-type sacral fracture in twenty synthetic replicas of a male pelvis articulated to the lumbar spine, L1 to sacrum, (Model: 1300, SawbonesTM; Pacific Research Laboratories, Vashon, WA, USA), instrumented with four different techniques, were mechanically tested. We made 4 different constructs in 5 specimen samples for each construct. Groups: Group 1. Instrumentation of the L5-Iliac bones with TTS. Group 2. Instrumentation of the L4-L5-Iliac bones with TTS. Group 3. Instrumentation of L5-Iliac bones without TTS. Group 4: Instrumentation of L4-L5-Iliac bones without TTS. RESULTS AND CONCLUSIONS: According to our results, it can be concluded that in SPD, better stability is obtained when proximal fixation is only up to L5, without including L4 (alternative hypothesis), the addition of transiliac-transsacral fixations is essential.

Activation of GABA-B receptors induced by systemic amphetamine abolishes dopamine release in the rat lateral septum.

The lateral septum is a brain nucleus involved in various mental disorders such as anxiety and drug addiction. In the present study, we investigated whether systemic amphetamine, known to release dopamine (DA) in nucleus accumbens, will also release DA in lateral septum. Our results show that systemic amphetamine administration (2 mg/kg i.p.) induced a significant increase in DA extracellular levels in nucleus accumbens but not in lateral septum. Interestingly, intralateral septum perfusion of amphetamine through the microdialysis probe induced a significant increase in DA extracellular levels. To test if GABAergic neurotransmission in lateral septum was responsible for inhibiting the release of DA when amphetamine was administered systemically, we perfused a GABA-B selective antagonist (CGP-52432) intra lateral septum. Systemic amphetamine administration induced a significant increase in lateral septum DA release when CGP-52432 was concomitantly superfused. Our results indicate that the systemic administration of amphetamine induces an increase in lateral septum GABA release and the consequent activation of GABA-B receptors counteracting the direct effect of amphetamine on lateral septum DA release.

Evaluación de la función renal con la fórmula CKD-EPI y factores de riesgo que predisponen a su disminución en adultos mayores de 60 años / Kidney function evaluation with CKD-EPI equation and risk factors that prevent its decrease in elderly people

Objetivo: estimar la filtración glomerular mediante la ecuación CKD-EPI a partir de la concentración de creatinina sérica en pacientes mayores de 60 años de edad con el fin de estadificarlos, además de identificar los factores de riesgo que conllevan a la progresión de su disminución diferenciándolos por edad y sexo. Método: se realizó un estudio descriptivo de carácter transversal, en pacientes mayores de 60 años que acuden al Hospital Municipal Andrés Cuschieri de Colcapirhua durante los meses de enero a junio del 2016 con una muestra de 408 pacientes de los cuales se realizó la revisión de la historia clínica, y estimación de la filtración glomerular a partir de la fórmula CKD-EPI, con la posterior clasificación e identificación de los factores de riesgo. Resultados: entre los más sobresalientes son que el sexo femenino presenta menor filtrado glomerular, la edad no fue un factor predisponente en este grupo, los factores de riesgo asociados a su disminución fueron la hipertensión arterial, diabetes mellitus y un IMC alterado. Conclusiones: el uso y conocimiento de la ecuación CKD-EPI es un instrumento de pesquisaje oportuno y de estadiaje; sin embargo, la identificación y corrección de los factores de riesgo son importantes para prevenir la progresión de la enfermedad.

Objective: to estimate the glomerular filtration rate using the CKD-EPI equation, based on the serum creatinine concentration in patients over 60 years of age, in order to staging them, as well as to identify the risk factors that lead to the progression of their decrease by differentiating them by age and sex. Method: a cross-sectional descriptive study was performed in patients older than 60 years of age who attended the Hospital Municipal Andrés Cuschieri from Colcapirhua during the months of January to June 2016 with a sample of 408 patients from whom it was realized the review of the clinical history, and estimation of glomerular filtration from the CKD-EPI formula, with subsequent classification and identification of risk factors. Results: among the most outstanding are that the female sex has less glomerular filtration, age was not a predisposing factor in this group, the risk factors associated with its decrease were hypertension, diabetes mellitus and a modified BMI. Conclusions: the use and knowledge of the CKD-EPI equation is an instrument of timely screening and staging; however, the identification and correction of risk factors are important in preventing the progression of the disease.

Rapid and sustained response to tocilizumab, anti-interleukin-6 receptor antibody, in a patient with nephrotic syndrome secondary to systemic juvenile idiopathic arthritis-related amyloidosis.

AA amyloidosis, or secondary amyloidosis, is a rare but serious complication of chronic inflammatory diseases. Chronic inflammatory arthritis is the commonest cause of AA amyloidosis and, when the latter appears, treatment can be frustrating. Deposition of fibrils, derived from circulating acute-phase reactant serum amyloid A protein (SAA), in the kidneys can lead to proteinuria and progressive loss of renal function. We describe the case of a 14-year-old female with systemic juvenile idiopathic arthritis who developed nephrotic syndrome secondary to AA amyloidosis; while she was unresponsive to all measures, including anti-tumour necrosis factor therapy, treatment with tocilizumab, an anti-human interleukin-6 receptor antibody, immediately normalized the SAA and reversed the nephrotic syndrome. We discuss this new therapeutic approach.