333 research outputs found
The Grasping Side of Odours
Background: Research on multisensory integration during natural tasks such as reach-to-grasp is still in its infancy. Crossmodal links between vision, proprioception and audition have been identified, but how olfaction contributes to plan and control reach-to-grasp movements has not been decisively shown. We used kinematics to explicitly test the influence of olfactory stimuli on reach-to-grasp movements. Methodology/Principal Findings: Subjects were requested to reach towards and grasp a small or a large visual target (i.e., precision grip, involving the opposition of index finger and thumb for a small size target and a power grip, involving the flexion of all digits around the object for a large target) in the absence or in the presence of an odour evoking either a small or a large object that if grasped would require a precision grip and a whole hand grasp, respectively. When the type of grasp evoked by the odour did not coincide with that for the visual target, interference effects were evident on the kinematics of hand shaping and the level of synergies amongst fingers decreased. When the visual target and the object evoked by the odour required the same type of grasp, facilitation emerged and the intrinsic relations amongst individual fingers were maintained. Conclusions/Significance: This study demonstrates that olfactory information contains highly detailed information able to elicit the planning for a reach-to-grasp movement suited to interact with the evoked object. The findings offer a substantia
VST - VLT Survey Telescope Integration Status
The VLT Survey Telescope (VST) is a 2.6m aperture, wide field, UV to I
facility, to be installed at the European Southern Observatory (ESO) on the
Cerro Paranal Chile. VST was primarily intended to complement the observing
capabilities of VLT with wide-angle imaging for detecting and
pre-characterising sources for further observations with the VLT.Comment: 2 pages, 2 figures, conferenc
Feasibility and reproducibility of right ventricle stress echocardiography and its capability to assess the right ventricle contractile reserve of patient with at least trivial tricuspid regurgitation
Abstract
Funding Acknowledgements
Type of funding sources: None.
BACKGROUND. Stress echocardiography (SE) is widely used for the assessment of left ventricular (LV) function, diagnostic and prognostic stratification of patients with coronary artery disease and for assessment of mitral and aortic valve disease. However, the assessment of the right ventricle (RV) in general, and in particular in regard to the contractile reserve of the RV in patients with tricuspid valve (TV) disease is an area that has not been previously explored in adult patients. The physiology and function of the RV is different than that of the LV and the use of SE provides the possibility to test both systolic and diastolic function of the RV in response to increased loading conditions. This can potentially be used to assess the RV function prior to surgery and to predict which subset of patients may benefit from intervention on the TV before the RV displays signs of failure
PURPOSE. We therefore propose a study to investigate the potential use of SE for the assessment of RV function in adult patients. The aim is to evaluate the feasibility of RV SE in any patients with more than trivial tricuspid regurgitation (TR) and to assess the presence and degree of RV contractile reserve.
METHODS. We enrolled 81 patients undergoing a phisical or dobutamine SE for CV risk stratification or chest pain. Inclusion criteria were age≥ 18 years, normal baseline RV function (FAC> 35%, TAPSE> 16 mm). Exclusion criteria were presence of RV dysfunction, pulmonary stress hypertension, positive stress test for left myocardial ischemia, presence of moderate or severe valvular disease, grade III or higher diastolic dysfunction at baseline, severe respiratory, renal or hepatic dysfunction. We evaluated the average values of TAPSE, fractional area change (FAC), S wave, sPAP (pulmonary systolic blood pressure), RV strain during baseline and at the peak of the effort. We also assessed the reproducibility of these measurement between two different expert operators (blind analysis).
RESULTS. We were able to measure the RV parameters both during baseline and at the peak of the effort in all patients, demonstrating an excellent feasibility. Differences in parameters collected at baseline and at peak were assessed using paired Wilcoxon signed rank test. All variables showed a statistical significant increase (p < 0.001) at peak compared to the baseline. Average percentage increases at peak were 31.1% for TAPSE, 24,8% for FAC, 50,6% for S wave, 55,2% for PAPS and 39.8 % for RV strain. Bland-Altman method was used to evaluate the agreement between measurements collected by two separate operators and it showed good Intraclass Correlation Coefficients (Figure).
CONCLUSIONS. RV SE proved to be feasible and showed little inter-operator variability in patients with at least trivial TR. It provided valuable informations about RV contractile reserve that may help stratifying the risk of RV failure in patients undergoing TV surgery.
Abstract Figur
Lentiviral gene therapy corrects platelet phenotype and function in patients with Wiskott-Aldrich syndrome
BACKGROUND:
Thrombocytopenia is a serious issue for all patients with classical Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT) because it causes severe and life-threatening bleeding. Lentiviral gene therapy (GT) for WAS has shown promising results in terms of immune reconstitution. However, despite the reduced severity and frequency of bleeding events, platelet counts remain low in GT-treated patients.
OBJECTIVE:
We carefully investigated platelet defects in terms of phenotype and function in untreated patients with WAS and assessed the effect of GT treatment on platelet dysfunction.
METHODS:
We analyzed a cohort of 20 patients with WAS/XLT, 15 of them receiving GT. Platelet phenotype and function were analyzed by using electron microscopy, flow cytometry, and an aggregation assay. Platelet protein composition was assessed before and after GT by means of proteomic profile analysis.
RESULTS:
We show that platelets from untreated patients with WAS have reduced size, abnormal ultrastructure, and a hyperactivated phenotype at steady state, whereas activation and aggregation responses to agonists are decreased. GT restores platelet size and function early after treatment and reduces the hyperactivated phenotype proportionally to WAS protein expression and length of follow-up.
CONCLUSIONS:
Our study highlights the coexistence of morphologic and multiple functional defects in platelets lacking WAS protein and demonstrates that GT normalizes the platelet proteomic profile with consequent restoration of platelet ultrastructure and phenotype, which might explain the observed reduction of bleeding episodes after GT. These results are instrumental also from the perspective of a future clinical trial in patients with XLT only presenting with microthrombocytopenia
Perception of Shadows in Children with Autism Spectrum Disorders
Background: Cast shadows in visual scenes can have profound effects on visual perception. Much as they are informative, they also constitute noise as they are salient features of the visual scene potentially interfering with the processing of other features. Here we asked i) whether individuals with autism can exploit the information conveyed by cast shadows; ii) whether they are especially sensitive to noise aspects of shadows. Methodology/Principal Findings: Twenty high-functioning children with autism and twenty typically developing children were asked to recognize familiar objects while the presence, position, and shape of the cast shadow were systematically manipulated. Analysis of vocal reaction time revealed that whereas typically developing children used information from cast shadows to improve object recognition, in autistic children the presence of cast shadows—either congruent or incongruent—interfered with object recognition. Critically, vocal reaction times were faster when the object was presented without a cast shadow. Conclusions/Significance: We conclude that shadow-processing mechanisms are abnormal in autism. As a result, processing shadows becomes costly and cast shadows interfere rather than help object recognition
Grasping Kinematics from the Perspective of the Individual Digits: A Modelling Study
Grasping is a prototype of human motor coordination. Nevertheless, it is not known what determines the typical movement patterns of grasping. One way to approach this issue is by building models. We developed a model based on the movements of the individual digits. In our model the following objectives were taken into account for each digit: move smoothly to the preselected goal position on the object without hitting other surfaces, arrive at about the same time as the other digit and never move too far from the other digit. These objectives were implemented by regarding the tips of the digits as point masses with a spring between them, each attracted to its goal position and repelled from objects' surfaces. Their movements were damped. Using a single set of parameters, our model can reproduce a wider variety of experimental findings than any previous model of grasping. Apart from reproducing known effects (even the angles under which digits approach trapezoidal objects' surfaces, which no other model can explain), our model predicted that the increase in maximum grip aperture with object size should be greater for blocks than for cylinders. A survey of the literature shows that this is indeed how humans behave. The model can also adequately predict how single digit pointing movements are made. This supports the idea that grasping kinematics follow from the movements of the individual digits
Democratic Teacher Education Practices
[Living reference work entry]
This entry provides an insight into the turbulent and recently disappointing events in the history of Design and Technology (D&T) teacher education in England over the last 150 years. It is a complex journey that needs to include a review of the generic history of teacher education in England, the differing educational needs of children, the changing role of D&T as a school curriculum subject, the requirements for an appropriately trained workforce to meet the economic needs of the country, and how various government educational initiatives and interventions (Gillard 2018) have affected how teachers in general and D&T teachers in particular have been and still are trained today. All these factors are inseparably intertwined. Therefore, this entry discusses them all together in chronological date order
Avoiding moving obstacles
To successfully move our hand to a target, we must consider how to get there without hitting surrounding objects. In a dynamic environment this involves being able to respond quickly when our relationship with surrounding objects changes. People adjust their hand movements with a latency of about 120 ms when the visually perceived position of their hand or of the target suddenly changes. It is not known whether people can react as quickly when the position of an obstacle changes. Here we show that quick responses of the hand to changes in obstacle position are possible, but that these responses are direct reactions to the motion in the surrounding. True adjustments to the changed position of the obstacle appeared at much longer latencies (about 200 ms). This is even so when the possible change is predictable. Apparently, our brain uses certain information exceptionally quickly for guiding our movements, at the expense of not always responding adequately. For reaching a target that changes position, one must at some time move in the same direction as the target did. For avoiding obstacles that change position, moving in the same direction as the obstacle is not always an adequate response, not only because it may be easier to avoid the obstacle by moving the other way, but also because one wants to hit the target after passing the obstacle. Perhaps subjects nevertheless quickly respond in the direction of motion because this helps avoid collisions when pressed for time. © 2008 Springer-Verlag
When Ears Drive Hands: The Influence of Contact Sound on Reaching to Grasp
Background
Most research on the roles of auditory information and its interaction with vision has focused on perceptual performance. Little is known on the effects of sound cues on visually-guided hand movements.
Methodology/Principal Findings
We recorded the sound produced by the fingers upon contact as participants grasped stimulus objects which were covered with different materials. Then, in a further session the pre-recorded contact sounds were delivered to participants via headphones before or following the initiation of reach-to-grasp movements towards the stimulus objects. Reach-to-grasp movement kinematics were measured under the following conditions: (i) congruent, in which the presented contact sound and the contact sound elicited by the to-be-grasped stimulus corresponded; (ii) incongruent, in which the presented contact sound was different to that generated by the stimulus upon contact; (iii) control, in which a synthetic sound, not associated with a real event, was presented. Facilitation effects were found for congruent trials; interference effects were found for incongruent trials. In a second experiment, the upper and the lower parts of the stimulus were covered with different materials. The presented sound was always congruent with the material covering either the upper or the lower half of the stimulus. Participants consistently placed their fingers on the half of the stimulus that corresponded to the presented contact sound.
Conclusions/Significance
Altogether these findings offer a substantial contribution to the current debate about the type of object representations elicited by auditory stimuli and on the multisensory nature of the sensorimotor transformations underlying action
- …