209 research outputs found
Abnormal Visuo-vestibular Interactions in Vestibular Migraine: a Cross Sectional Study
Vestibular migraine is amongst the commonest causes of episodic vertigo. Chronically, patients with vestibular migraine develop abnormal responsiveness to both vestibular and visual stimuli characterised by heightened self-motion sensitivity and visually-induced dizziness. Yet, the neural mechanisms mediating such symptoms remain unknown. We postulate that such symptoms are attributable to impaired visuo-vestibular cortical interactions, which in-turn disrupts normal vestibular function. To assess this, we investigated whether prolonged, full-field visual motion exposure, which has previously been shown to modulate visual cortical excitability in both healthy individuals and avestibular patients, could disrupt vestibular ocular reflex (VOR) and vestibular-perceptual thresholds of self-motion during rotations. Our findings reveal that vestibular migraine patients exhibited abnormally elevated reflexive and perceptual vestibular thresholds at baseline. Following visual motion exposure, both reflex and perceptual thresholds were significantly further increased in vestibular migraine patients relative to healthy controls, migraineurs without vestibular symptoms and patients with episodic vertigo due to a peripheral inner-ear disorder. Our results provide support for the notion of altered visuo-vestibular cortical interactions in vestibular migraine, as evidenced by vestibular threshold elevation following visual motion exposure
Desempenho de alevinos de jundiá alimentados com silagem de rejeito de peixe
O objetivo deste trabalho foi avaliar o desempenho zootécnico de alevinos de jundiá, alimentados com silagem de rejeitos de pescado, em substituição ao farelo de soja e à levedura de cana. Durante 35 dias, 375 alevinos de jundiá com peso inicial de 1,73±0,17 g, distribuídos em delineamento inteiramente casualizado, foram avaliados em cinco tratamentos e quatro repetições. Os tratamentos consistiram de inclusão de silagem de pescado a 0, 12,5, 25, 37,5 e 50%. Todos os parâmetros zootécnicos avaliados, exceto o fator de condição, mostraram que a substituição do farelo de soja e da levedura pela silagem de rejeito de pescado melhora o desempenho produtivo de alevinos de jundiá
Meios de cultura no desenvolvimento de ápices caulinares de mamoneira (Ricinus communis L.) in vitro
High Precision Measurement of the Proton Elastic Form Factor Ratio at low
We report a new, high-precision measurement of the proton elastic form factor
ratio \mu_p G_E/G_M for the four-momentum transfer squared Q^2 = 0.3-0.7
(GeV/c)^2. The measurement was performed at Jefferson Lab (JLab) in Hall A
using recoil polarimetry. With a total uncertainty of approximately 1%, the new
data clearly show that the deviation of the ratio \mu_p G_E/G_M from unity
observed in previous polarization measurements at high Q^2 continues down to
the lowest Q^2 value of this measurement. The updated global fit that includes
the new results yields an electric (magnetic) form factor roughly 2% smaller
(1% larger) than the previous global fit in this Q^2 range. We obtain new
extractions of the proton electric and magnetic radii, which are
^(1/2)=0.875+/-0.010 fm and ^(1/2)=0.867+/-0.020 fm. The charge
radius is consistent with other recent extractions based on the electron-proton
interaction, including the atomic hydrogen Lamb shift measurements, which
suggests a missing correction in the comparison of measurements of the proton
charge radius using electron probes and the recent extraction from the muonic
hydrogen Lamb shift.Comment: 12 pages, 3 figure
Surface modifications for antimicrobial effects in the healthcare setting: a critical overview
The spread of infections in healthcare environments is a persistent and growing problem in most countries, aggravated by the development of microbial resistance to antibiotics and disinfectants. In addition to indwelling medical devices (e.g. implants, catheters), such infections may also result from adhesion of microbes either to external solid–water interfaces such as shower caps, taps, drains, etc., or to external solid–gas interfaces such as door handles, clothes, curtains, computer keyboards, etc. The latter are the main focus of the present work, where an overview of antimicrobial coatings for such applications is presented. This review addresses well-established and novel methodologies, including chemical and physical functional modification of surfaces to reduce microbial contamination, as well as the potential risks associated with the implementation of such anticontamination measures. Different chemistry-based approaches are discussed, for instance anti-adhesive surfaces (e.g. superhydrophobic, zwitterions), contact-killing surfaces (e.g. polymer brushes, phages), and biocide-releasing surfaces (e.g. triggered release, quorum sensing-based systems). The review also assesses the impact of topographical modifications at distinct dimensions (micrometre and nanometre orders of magnitude) and the importance of applying safe-by-design criteria (e.g. toxicity, contribution for unwanted acquisition of antimicrobial resistance, long-term stability) when developing and implementing antimicrobial surfaces
- …