Search results for " MOTOR"

A Rotor Flux and Speed Observer for Sensorless Single-Phase Induction Motor Applications

2012

It is usual to find single-phase induction motor (SPIM) in several house, office, shopping, farm, and industry applications, which are become each time more sophisticated and requiring the development of efficient alternatives to improve the operational performance of this machine. Although the rotor flux and rotational speed are essential variables in order to optimize the operation of a SPIM, the use of conventional sensors to measure them is not a viable option. Thus, the adoption of sensorless strategies is the more reasonable proposal for these cases. This paper presents a rotor flux and rotational speed observer for sensorless applications involving SPIMs. Computer simulations and the…

Sequential visual reaction times

1988

The reaction-time to a series of successive digits was measured on two subjects. After practice, it was found that whilst the reaction time to the onset of the series was constant at 150 ms, the response time to additional digits became less and less to asymptote to a level of about 50 ms. The time course of this ‘chorus-line’ phenomenon was studied in greater temporal detail by varying the interval in steps of 20 ms. The effect was greatest at 200 ms. Thereafter, it declined and for long intervals reached the value of a standard reaction time. On a third inexperienced subject, the learning period was established; this was about 300–400 presentations. The implications of these findings are …

Brainstem diseases causing isolated ocular motor nerve palsies

2004

There is a significant number of individual patients with ocular motor nerve palsies as the only clinical sign of MRI- and, less frequently, CT-documented small brainstem lesions with a predominanc...

Intraflagellar transport proteins in ciliogenesis of photoreceptor cells

2011

Background information. The assembly and maintenance of cilia depend on IFT (intraflagellar transport) mediated by molecular motors and their interplay with IFT proteins. Here, we have analysed the involvement of IFT proteins in the ciliogenesis of mammalian photoreceptor cilia. Results. Electron microscopy revealed that ciliogenesis in mouse photoreceptor cells follows an intracellular ciliogenesis pathway, divided into six distinct stages. The first stages are characterized by electron-dense centriolar satellites and a ciliary vesicle, whereas the formations of the ciliary shaft and the light-sensitive outer segment discs are features of the later stages. IFT proteins were associated with…

Picco di massa ossea ed attività fisica: confronto tra giovani adulti sedentari, attivi e atleti

2009

OBIETTIVO - Valutare, nel periodo di raggiungimento del picco di massa ossea, gli effetti dell’attività fisica sulla mineralizzazione ossea in età giovanile. MATERIALI E METODI - Allo studio hanno partecipato 43 soggetti maschi, sani, con età media di 25 anni, suddivisi in tre gruppi in relazione all’intensità dell’attività fisica svolta dall’età di dieci anni in poi: il primo composto da 17 soggetti sedentari, il secondo da 16 soggetti attivi e il terzo da 15 soggetti atleti. Ogni soggetto è stato sottoposto a mineralometria ossea computerizzata (DEXA). La misurazione della densità ossea (BMD, g/cm2) dei soggetti ha riguardato: corpo intero (Total Body), collo femore dx e sx e tratto rachi…

Frequency-specific network activity predicts bradykinesia severity in Parkinson’s disease

2021

Highlights • Parallel subnetworks are affected in bradykinesia. • The primary motor and the premotor cortex are common nodes with task-specificity. • Beta activity decreases, gamma activity increases with improvement of bradykinesia. • Subthalamic stimulation reduces beta, increases gamma power in ipsilateral cortex. • Subnetworks act with frequency-specific oscillations.

Linguistic, psychometric validation and diagnostic ability assessment of an Italian version of a 19-item wearing-off questionnaire for wearing-off de…

2012

Carcinoma of the tongue and bulbar-onset amyotrophic lateral sclerosis: unusual differential diagnosis.

2007

We present a 72-year-old woman with progressive dysphagia, dysarthria and tongue palsy who was initially diagnosed with bulbar-onset amyotrophic lateral sclerosis (ALS). However, the absence of atrophy or fasciculations in the tongue, as in other voluntary muscles, and the lack of reproducible neurophysiological evidence of denervation, prompted a revision of the diagnostic work-up, which eventually led to the discovery of a carcinoma of the tongue. This case report describes a relatively rare type of oropharyngeal carcinoma that, in its early stage, resembled a bulbar-onset ALS. This differential diagnosis is unusual, and it was fostered by the persistent lack of atrophy of the tongue and …

Neuropathologic and morphometric studies in hereditary motor and sensory neuropathy type II with neurofilament accumulation.

1986

Histological, electron microscopic and morphometric data on sural nerve, muscle, and skin biopsies of three patients affected by autosomal dominant hereditary motor and sensory neuropathy type II with neurofilament accumulation, whose neurological, cardiological and electrophysiological data have been provided in a previous paper disclosed focally enlarged myelinated axons, due to aggregation of neurofilaments in sural nerves of all 3 biopsied patients, as well as densely packed clusters of filaments in occasional non-myelinated axons without axonal enlargement, in several fibroblasts and endothelial cells in muscle and particularly in skin. This accumulation of filaments was less pronounce…

Presenilin-1 Mutations Are a Cause of Primary Lateral Sclerosis-Like Syndrome

2021

6 páginas, 2 figuras