Search results for " Conduction"

2019

AbstractDuring early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in theDrosophilagiant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelinated…

Thermal response test analysis for U-pipe vertical borehole heat exchangers under groundwater flow conditions

2021

[EN] Conventional models used in the analysis of thermal response test data only consider conduction as heat transfer mechanism. In cases where presence of groundwater is detected, convection heat transmission plays an important role, so its influence must be determined in the calculation of the effective thermal conductivity, usually overestimated in these situations, increasing its value the higher the power injected and the time elapsed. In this work, based on the data collected in a borehole located at UPV (Valencia) in which have been carried out three thermal response tests with different characteristics, has been implemented a variation of the finite line source model introducing an …

Factors affecting basket catheter detection of real and phantom rotors in the atria: A computational study

2018

[EN] Anatomically based procedures to ablate atrial fibrillation (AF) are often successful in terminating paroxysmal AF. However, the ability to terminate persistent AF remains disappointing. New mechanistic approaches use multiple-electrode basket catheter mapping to localize and target AF drivers in the form of rotors but significant concerns remain about their accuracy. We aimed to evaluate how electrode-endocardium distance, far-field sources and inter-electrode distance affect the accuracy of localizing rotors. Sustained rotor activation of the atria was simulated numerically and mapped using a virtual basket catheter with varying electrode densities placed at different positions withi…

Calculations of high-power production target and beamdump for the GSI future Super-FRS for a fast extraction scheme at the FAIR Facility

2005

A superconducting fragment separator (Super-FRS) is being designed for the production and separation of radioactive isotopes at the future FAIR (Facility for Antiprotons and Ion Research) facility at Darmstadt. This paper discusses various aspects and requirements for the high-power production target that will be used in the Super-FRS experiments. The production target must survive over an extended period of time as it will be used during the course of many experiments. The specific power deposited by the high intensity beam that will be generated at the future FAIR facility will be high enough to destroy the target in most of the cases as a result of a single shot from the new heavy ion sy…

P and R Wave Detection in Complete Congenital Atrioventricular Block

2009

Complete atrioventricular block (type III AVB) is characterized by an absence of P wave transmission to ventricles. This implies that QRS complexes are generated in an autonomous way and are not coordinated with P waves. This work introduces a new algorithm for the detection of P waves for this type of pathology using non-invasive electrocardiographic surface leads. The proposed algorithm is divided into three stages. In the first stage, the R waves located by a QRS detector are used to generate the RR series and time references for the other stages of the algorithm. In the second stage, the ventricular activity (QT segment) is removed by using an adaptive filter that obtains an averaged pa…

Influence of digoxin on sinus node function after pharmacologic autonomic blockade.

1983

The effect of iv digoxin on normal sinus node function was studied after pharmacologic autonomic blockade (AB) in ten patients. Sinus cycle length (SCL), sinus node recovery time (SNRT) and sinoatrial conduction time (SACT) were determined before and after AB with propranolol (0.2 mg/kg body weight) and atropine sulfate (0.04 mg/kg body weight) iv, and 15 min, 30 min, and 45 min after 1 mg iv digoxin. AB resulted in a significant decrease (P less than 0.01) in SCL (916 +/- 158 to 716 +/- 120 ms), in SNRT (1,229 +/- 221 to 871 +/- 190 ms), and in SACT (79 +/- 34 to 44 +/- 10 ms). Fifteen minutes after iv digoxin there was no significant change observed in SCL (716 +/- 120 to 708 +/- 92 ms), …

Peripheral nerve involvement in chronic liver disease. Clinical and electrophysiological study.

1986

A clinical and electrophysiological study was carried out on 19 selected patients with chronic liver disease. Clinical signs of peripheral nerve involvement were found in 4 patients (21%); while electrophysiological impairment was present in 11 patients (57.8%). These abnormalities were mostly limited to the sensory and motor fibers of the tibialis posterior nerve. Our data confirm the presence of peripheral nerve involvement in chronic liver disease, and that it may be evidenced by careful electrophysiological examination.

Phenotype and natural history of inherited neuropathies caused byHSJ1c.352+1G>A mutation

2015

Mutations in the HSJ1 ( Heat-Shock Protein J1 ) gene, also called DNAJB2 (DnaJ (Hsp40) homologue, subfamily B, member 2), have been recently described as a cause of hereditary neuropathies. The HSJ1 c.352+1G>A mutation in homozygote state has been reported as the causative mutation in a single family with autosomal recessive distal hereditary motor neuropathy (dHMN).1 Since then, two other families with different HSJ1 mutations have been described: one with a dHMN phenotype and the other with a Charcot-Marie-Tooth disease type 2 (CMT2) phenotype.2 We identified the HSJ1 c.352+1G>A mutation in 10 patients who underwent long-lasting follow-up. We describe their phenotype and clinical evolutio…

KTP-laser stapedotomy with a self-crimping, thermal shape memory Nitinol SMart piston: 1 year follow-up results: how we do it.

2008

Genome-Wide Association Studies of the PR Interval in African Americans.

2011

The PR interval on the electrocardiogram reflects atrial and atrioventricular nodal conduction time. The PR interval is heritable, provides important information about arrhythmia risk, and has been suggested to differ among human races. Genome-wide association (GWA) studies have identified common genetic determinants of the PR interval in individuals of European and Asian ancestry, but there is a general paucity of GWA studies in individuals of African ancestry. We performed GWA studies in African American individuals from four cohorts (n = 6,247) to identify genetic variants associated with PR interval duration. Genotyping was performed using the Affymetrix 6.0 microarray. Imputation was p…