180 research outputs found
Improvement of salt corrosion resistance of titanium alloys by PVD and CVD coatings
The corrosion resistance of two kind of coating systems was investigated to protect a Ti-6242 titanium under hot salt stress corrosion conditions: PVD silicon coatings and CVD alumina coating. All these coatings were tested under hot Salt Stress Corrosion (SSC) with a constant static mechanical stress and cyclic temperature conditions, and have been brought near to the real industrial work conditions. Although all coated specimens were damaged in salted area, both SiC and Al2O3 coatings showed no SSC rupture during 100 h,while SixNy lifetime under SSC conditions was increased by a factor 2 compared to noncoated one. As well as these interesting quantitative results, coated specimens exhibit a good adherence on titanium substrate
Sensory supplementation system based on electrotactile tongue biofeedback of head position for balance control
The present study aimed at investigating the effects of an artificial head
position-based tongue-placed electrotactile biofeedback on postural control
during quiet standing under different somatosensory conditions from the support
surface. Eight young healthy adults were asked to stand as immobile as possible
with their eyes closed on two Firm and Foam support surface conditions executed
in two conditions of No-biofeedback and Biofeedback. In the Foam condition, a
6-cm thick foam support surface was placed under the subjects' feet to alter
the quality and/or quantity of somatosensory information at the plantar sole
and the ankle. The underlying principle of the biofeedback consisted of
providing supplementary information about the head orientation with respect to
gravitational vertical through electrical stimulation of the tongue. Centre of
foot pressure (CoP) displacements were recorded using a force platform. Larger
CoP displacements were observed in the Foam than Firm conditions in the two
conditions of No-biofeedback and Biofeedback. Interestingly, this destabilizing
effect was less accentuated in the Biofeedback than No-biofeedback condition.
In accordance with the sensory re-weighting hypothesis for balance control, the
present findings evidence that the availability of the central nervous system
to integrate an artificial head orientation information delivered through
electrical stimulation of the tongue to limit the postural perturbation induced
by alteration of somatosensory input from the support surface
Postural control during quiet standing following cervical muscular fatigue: effects of changes in sensory inputs
The purpose of the present experiment was to investigate the effects of
cervical muscular fatigue on postural control during quiet standing under
different conditions of reliability and/or availability of somatosensory inputs
from the plantar soles and the ankles and visual information. To this aim, 14
young healthy adults were asked to sway as little as possible in three sensory
conditions (No vision, No vision-Foam support and Vision) executed in two
conditions of No fatigue and Fatigue of the scapula elevator muscles. Centre of
foot pressure (CoP) displacements were recorded using a force platform. Results
showed that (1) the cervical muscular fatigue yielded increased CoP
displacements in the absence of vision, (2) this effect was more accentuated
when somatosensation was degraded by standing on a foam surface and (3) the
availability of vision allowed the individuals to suppress this destabilising
effect. On the whole, these findings not only stress the importance of intact
cervical neuromuscular function on postural control during quiet standing, but
also suggest a reweigthing of sensory cues in balance control following
cervical muscular fatigue by increasing the reliance on the somatosensory
inputs from the plantar soles and the ankles and visual information
3D reconstruction and comparison of shapes of DNA minicircles observed by cryo-electron microscopy
We use cryo-electron microscopy to compare 3D shapes of 158 bp long DNA minicircles that differ only in the sequence within an 18 bp block containing either a TATA box or a catabolite activator protein binding site. We present a sorting algorithm that correlates the reconstructed shapes and groups them into distinct categories. We conclude that the presence of the TATA box sequence, which is believed to be easily bent, does not significantly affect the observed shapes
A Wireless Embedded Tongue Tactile Biofeedback System for Balance Control
We describe the architecture of an original biofeedback system for balance
improvement for fall prevention and present results of a feasibility study. The
underlying principle of this biofeedback consists of providing supplementary
information related to foot sole pressure distribution through a wireless
embedded tongue-placed tactile output device. Twelve young healthy adults
voluntarily participated in this experiment. They were asked to stand as
immobile as possible with their eyes closed in two conditions of nobiofeedback
and biofeedback. Centre of foot pressure (CoP) displacements were recorded
using a force platform. Results showed reduced CoP displacements in the
biofeedback relative to the no-biofeedback condition. On the whole, the present
findings evidence the effectiveness of this system in improving postural
control on young healthy adults. Further investigations are needed to
strengthen the potential clinical value of this device.Comment: Pervasive and Mobile Computing (2008) in pres
Development of a standardized chart review method to identify drug-related hospital admissions in older people
Aim: We aimed to develop a standardized chart review method to identify drug-related hospital admissions (DRA) in older people caused by non-preventable adverse drug reactions and preventable medication errors including overuse, underuse and misuse of medications: the DRA adjudication guide. Methods: The DRA adjudication guide was developed based on design and test iterations with international and multidisciplinary input in 4 subsequent steps: literature review, evaluation of content validity using a Delphi consensus technique, a pilot test and a reliability study. Results: The DRA adjudication guide provides definitions, examples and step-by-step instructions to measure DRA. A 3-step standardized chart review method was elaborated including 1) data abstraction, 2) explicit screening with a newly developed trigger tool for DRA in older people and 3) consensus adjudication for causality by a pharmacist and a physician using the World Health Organization-Uppsala Monitoring Centre and Hallas criteria. A 15-member international Delphi panel reached consensus agreement on 26 triggers for DRA in older people. The DRA adjudication guide showed good feasibility of use and achieved moderate inter-rater reliability for the evaluation of 16 cases by 4 European adjudication pairs (71% agreement, kappa = 0.41). Disagreements arose mainly for cases with potential underuse. Conclusions: The DRA adjudication guide is the first standardized chart review method to identify DRA in older persons. Content validity, feasibility of use and inter-rater reliability were found to be satisfactory. The method can be used as an outcome measure for interventions targeted at improving quality and safety of medication use in older people
Exploring the social function of congregations: Acommunity development approach to develop âhub-and-spillâ early childhood development centres
This article reflects on the findings of a research study that investigated a community development project by CARITAS, a welfare organisation of the Dutch Reformed Church (DRC). The said organisation, together with local DRC congregations, and in a quest to address societal issues such as poverty and child neglect in the Northern Cape, developed early childhood development (ECD) centres in rural towns. The aim was to provide young children with quality care and to provide congregations with a platform to become active participants in community development projects. The study was conducted 5 years after the start of the project to explore the nature and value thereof. The outcomes of the study provide valuable insights regarding how such centres served as a tool to work towards ECD and a sense of community in these towns, while also addressing socio-economic issues. This article is aimed at presenting the findings as an example to be explored in other contexts
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