Search results for "Genetic Structures"
showing 10 items of 2107 documents
Influence of proprioceptive information on space orientation on the ground and in orbital weightlessness
1989
Conscious space orientation depends on afferent information from different sense organs including the labyrinth, the eyes, tactile cues from the skin, joint receptors, muscle spindles, tendon organs and possibly viscera. An important role is played by impulses from the cervical position receptors in interaction with concomitant information from the otolith system. In order to isolate the effect of cervical position receptors from that of the otolith system, space experiments in orbital weightlessness and in parabolic aircraft flight were performed. It was found that stimulation of the neck receptors in weightlessness markedly influences the perception of the subjective vertical and horizont…
Auditory cortical event-related potentials to pitch deviances in rats
1998
Abstract We recorded epidural event-related potentials (ERPs) from the auditory cortex in anesthetized rats when pitch-deviant tones were presented in a homogenous series of standard tones (oddball condition). Additionally, deviant tones were presented without standard tones (deviant-alone condition). ERPs to deviant tones in the oddball condition differed significantly from ERPs to standard tones at the latency range of 63–243 ms. On the other hand, ERPs to deviant tones in the deviant-alone condition did not differ from ERPs to standard tones until 196 ms from stimulus onset. The results suggest that oddball stimuli can be neurophysiologically discriminated in anesthetized rats. Furthermo…
The impact of a concurrent motor task on auditory and visual temporal discrimination tasks
2016
Previous studies have shown the presence of an interference effect on temporal perception when participants are required to simultaneously execute a nontemporal task. Such interference likely has an attentional source. In the present work, a temporal discrimination task was performed alone or together with a self-paced finger-tapping task used as concurrent, nontemporal task. Temporal durations were presented in either the visual or the auditory modality, and two standard durations (500 and 1, 500 ms) were used. For each experimental condition, the participant’s threshold was estimated and analyzed. The mean Weber fraction was higher in the visual than in the auditory modality, but only for…
Modifying auditory perception with prisms? Aftereffects of prism adaptation on a wide auditory spectrum in musicians and nonmusicians
2021
Prism adaptation consists of pointing to visual targets while wearing prisms that shift the visual field laterally. The aftereffects are not restricted to sensorimotor level but extend to spatial cognition. There is a link between spatial representation and auditory frequency, with an association of low frequencies on the left side and high frequencies on the right side of space. The present study aimed first at evaluating the representation of auditory frequencies on a wide range of frequencies in musicians and nonmusicians. We used the ‘auditory interval bisection judgment’ within three auditory intervals. The results showed a pseudoneglect behavior in pretest in musicians and nonmusician…
Cross-modal aftereffects of visuo-manual prism adaptation: Transfer to auditory divided attention in healthy subjects.
2021
OBJECTIVE Prism adaptation was shown to modify auditory perception. Using a dichotic listening task, which assesses auditory divided attention, benefits of a rightward prism adaptation were demonstrated in neglect patients (i.e., a syndrome following right hemisphere brain damage) by reducing their left auditory extinction. It is currently unknown whether prism adaptation affects auditory divided attention in healthy subjects. In the present study, we investigated the aftereffects of prism adaptation on dichotic listening. METHOD A sample of 47 young adults performed a dichotic listening task, in which pairs of words were presented with two words sounded simultaneously, one in each ear. Thr…
Adherence to international guidelines for the management of Helicobacter pylori infection among gastroenterologists and gastroenterology fellows in I…
2021
Background: Information on the management of Helicobacter (H.) pylori infection by gastroenterologists and gastroenterology fellows are scarce. We aimed to assess practice of gastroenterologists and gastroenterology fellows and their adherence to guidelines for diagnosis and treatment of H. pylori infection in Italy. Materials and Methods: All gastroenterologists and gastroenterology fellows attending the National Congress of Digestive Diseases - FISMAD were invited to fill-in an on-line questionnaire. The questionnaire included questions on the diagnosis and treatment of H. pylori infection. Results: A total of 279 gastroenterologists and 61 gastroenterology fellows participated to the stu…
Stain-free virtual histology of Bombus terrestris compound eyes by laboratory phase-contrast nano-CT
2021
The visual systems of pollinating insects are studied to understand the effects of a changing environment, and are to date imaged using microscopy or micro-CT. Microscopy only allows two-dimensional imaging and conventional micro-CT requires heavy-metal staining of the samples. Here we present virtual histology of compound eyes of bumblebee (Bombus terrestris) using a laboratory nano-CT system. Propagation-based phase-contrast CT allows three-dimensional imaging of samples without using any staining. Micrometre-resolution images of the microanatomy of the eyes were reconstructed, and the features identified in CT (cornea, crystalline cones, pigment, photoreceptor cells, basement membrane) w…
Functional and biomechanical changes in keratoconic corneas after implantation of intracorneal ring segments 5 and 6mm in diameter
2012
Purpose To determinate biomechanical and functional changes in human keratoconic corneas after triangular section ring implantation in two designs. Methods Retrospective study of biomechanical properties of 46 patients (60 eyes) with keratoconus undergoing surgery Keraring® intracorneal ring segments divided into two groups according to 5 or 6 mm of diameter. Surgical technique to made the channel was with IntraLase femtosecond laser. UCVA and BSCVA were measured and biomechanical factors provided by the device ORA before surgery and postoperatively one month, 3 months and 6 months. Results After surgery, we obtained a significant increase (p 0.05). At baseline- 6 months, the improvement in…
Vitrectomía enzimática por inyección intravítrea de plasmina autóloga como tratamiento inicial del edema macular diabético difuso
2008
espanolObjetivo: Determinar si la inyeccion intravitrea de plasmina es efectiva en el tratamiento del edema macular diabetico difuso (EMDD). Diseno: Estudio piloto prospectivo, comparativo, de intervencion, serie de casos. Pacientes: Dieciocho pacientes con edema macular diabetico bilateral, recibieron como primera actuacion terapeutica una inyeccion intravitrea de plasmina en un ojo, sirviendo el ojo contralateral como control. Tratamiento: Inyeccion intravitrea de 0,2 ml de plasmina autologa bajo anestesia topica. La plasmina fue obtenida por un metodo simplificado. Principales medidas: Engrosamiento macular central (EMC) medido por tomografia de coherencia optica (OCT) y agudeza visual (…
Nested allosteric interactions in extracellular hemoglobin of the leech Macrobdella decora
2003
Hemoglobin from the leech Macrobdella decora belongs to the class of giant extracellular hexagonal bilayer globin structures found in annelid and vestimentiferan worms. These complexes consist of 144 heme-bearing subunits, exhibit a characteristic quaternary structure (2 × (6 × (3 × 4))), and contain tetramers as basic substructures that express cooperative oxygen binding and thus provide a structural basis for a hierarchy in allosteric interactions. A thorough analysis of the isolated tetramer indicates that it functions as a trimer of cooperatively interacting subunits and a non-cooperative monomer rather than as four interacting subunits. A thermodynamic analysis of the whole molecule fa…