Flexible right sized honing technology for fast engine finishing

The paper discusses a flexible honing technology by describing the new prototype machine with its specificity. Three original methods produced by the flexible honing prototype have been studied. A path combines the two contemporary methods of industrial honing: the helical slide honing at 135 ° at the bottom of the cylinder and the conventional honing at 45 ° on the upper part. This method of honing shows the effectiveness of specific motion tracking to remove traces of inversions. Circular trajectories with large radii can be traveled quickly without consuming too much energy. The high cutting speed promotes the removal of material thus saving time. Finally, the multi-circle paths can get original textures thus proving the feasibility of all patterns

L'encodage de la forme par le toucher haptique

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Activité physique chez les adultes ayant subi un traumatisme craniocérébral présentant des symptômes dépressifs : recension des écrits et vision de professionnels

Le traumatisme craniocérébral (TCC) constitue une préoccupation importante pour le système de santé étant donné les nombreuses difficultés fonctionnelles associées, telles que des difficultés physiques et cognitives, mais aussi des symptômes dépressifs et des troubles de l’humeur. Pour un ergothérapeute travaillant avec une clientèle TCC, le lien entre ces dimensions physiques et affectives est particulièrement intrigant. Dans le présent article, nous documenterons tout d’abord, par une recension des écrits, l’effet de l’activité physique sur les symptômes dépressifs chez les clients adultes ayant subi un TCC. Dans un second temps, nous vérifierons l’applicabilité de ces résultats en clinique auprès de professionnels de la santé. Pour ce faire, une recension des écrits à partir de CINAHL et PubMed a été effectuée, en utilisant le MCREO comme cadre conceptuel pour analyser les résultats. Les résultats ont ensuite été présentés à un groupe de trois intervenants de la santé afin de connaître leur opinion quant aux facteurs favorisant et limitant l’implantation de l’intervention par l’activité physique dans leur pratique. Bien que le niveau de preuve soit modeste, les résultats de la recension des écrits suggèrent que l’activité physique a des effets bénéfiques quant à la réduction des symptômes dépressifs. En regard de ces conclusions, la principale recommandation est que les ergothérapeutes incluent l’activité physique en tant que facteur préventif des symptômes dépressifs chez les clients TCC

The influence of visual perspective on the somatosensory steady-state response during pain observation

The observation and evaluation of other's pain activate part of the neuronal network involved in the actual experience of pain, including those regions subserving the sensori-discriminative dimension of pain. This was largely interpreted as evidence showing that part of the painful experience can be shared vicariously. Here, we investigated the effect of the visual perspective from which other people’s pain is seen on the cortical response to continuous 25 Hz non-painful somatosensory stimulation (somatosensory steady-state response: SSSR). Based on the shared representation framework, we expected first-person visual perspective (1PP) to yield more changes in cortical activity than third-person visual perspective (3PP) during pain observation. Twenty healthy adults were instructed to rate a series of pseudo-dynamic pictures depicting hands in either painful or non-painful scenarios, presented either in 1PP (0°-45° angle) or 3PP (180° angle), while changes in brain activity was measured with a 128-electode EEG system. The ratings demonstrated that the same scenarios were rated on average as more painful when observed from the 1PP than from the 3PP. As expected from previous works, the SSSR response was decreased after stimulus onset over the left caudal part of the parieto-central cortex, contralateral to the stimulation side. Moreover, the difference between the SSSR was of greater amplitude when the painful situations were presented from the 1PP compared to the 3PP. Together, these results suggest that a visuospatial congruence between the viewer and the observed scenarios is associated with both a higher subjective evaluation of pain and an increased modulation in the somatosensory representation of observed pain. These findings are discussed with regards to the potential role of visual perspective in pain communication and empathy

The modulation of somatosensory resonance by psychopathic traits and empathy

A large number of neuroimaging studies have shown neural overlaps between first-hand experiences of pain and the perception of pain in others. This shared neural representation of vicarious pain is thought to involve both affective and sensorimotor systems. A number of individual factors are thought to modulate the cerebral response to other's pain. The goal of this study was to investigate the impact of psychopathic traits on the relation between sensorimotor resonance to other's pain and self-reported empathy. Our group has previously shown that a steady-state response to non-painful stimulation is modulated by the observation of other people's bodily pain. This change in somatosensory response was interpreted as a form of somatosensory gating (SG). Here, using the same technique, SG was compared between two groups of 15 young adult males: one scoring very high on a self-reported measure of psychopathic traits [60.8 ± 4.98; Levenson's Self-Report Psychopathy Scale (LSRP)] and one scoring very low (42.7 ± 2.94). The results showed a significantly greater reduction of SG to pain observation for the high psychopathic traits group compared to the low psychopathic traits group. SG to pain observation was positively correlated with affective and interpersonal facet of psychopathy in the whole sample. The high psychopathic traits group also reported lower empathic concern (EC) scores than the low psychopathic traits group. Importantly, primary psychopathy, as assessed by the LSRP, mediated the relation between EC and SG to pain observation. Together, these results suggest that increase somatosensory resonance to other's pain is not exclusively explained by trait empathy and may be linked to other personality dimensions, such as psychopathic traits

Topological properties of punctual Hilbert schemes of almost-complex fourfolds (I)

In this article, we study topological properties of Voisin's punctual Hilbert schemes of an almost-complex fourfold $X$. In this setting, we compute their Betti numbers and construct Nakajima operators. We also define tautological bundles associated with any complex bundle on $X$, which are shown to be canonical in $K$-theory

Homogeneous linewidth of the intraband transition at 1.55µm in GaN/AlN quantum dots.

PosterWe present homogeneous linewidth measurements of the intraband transition at 1.55 m in GaN/AlN quantum dots by means of non-linear spectral hole-burning experiments. The square-root dependence of the differential transmission signal with the incident pump power reveals the importance of electron-electron scattering in the population relaxation dynamics. We find on the contrary that this scattering process plays a minor role in the coherence relaxation dynamics since the homogeneous linewidth of 15 meV at 5K does not depend on the incident pump power. This suggests the predominance of other dephasing mechanisms such as spectral diffusion, and temperature-dependent measurements support this hypothesi

On the interpretation of drilling CFRP/Ti6Al4V stacks using the orthogonal cutting method: Chip removal mode and subsurface damage formation

The present paper aims to utilize the orthogonal cutting method to offer an enhanced interpretation of the drilling process on CFRP/Ti6Al4V stacks. It contributes to relating the chip separation modes of the orthogonal cutting of multilayer CFRP/Ti6Al4V stacks with their drilling characteristics. A particular focus was made to identify the effect of different cutting sequence strategies on the 3D topographies and defects formation of cut CFRP/Ti6Al4V stacks as well as the mechanisms controlling the drilling of the stack interface. Three configurations of orthogonal cutting operations considering both the impact of varying cutting sequence strategies and the combined interface machining were implemented and the in-situ chip removal characteristics were documented. Mechanical drilling of CFRP/Ti6Al4V stacks was performed subjected to varying cutting sequences and process parameters. Aspects involving the cutting forces, drilling-induced damage as well as the machined hole morphologies were carefully addressed with respect to the used cutting conditions. The obtained orthogonal cutting results were utilized to facilitate the stack drilling comprehension. The results discussed in this paper highlight the vital role of the cutting sequence strategy in the stack machinability and permit an enhanced interpretation of drilling this multilayer material

Activation of MEK1 or MEK2 isoform is sufficient to fully transform intestinal epithelial cells and induce the formation of metastatic tumors

<p>Abstract</p> <p>Background</p> <p>The Ras-dependent ERK1/2 MAP kinase signaling pathway plays a central role in cell proliferation control and is frequently activated in human colorectal cancer. Small-molecule inhibitors of MEK1/MEK2 are therefore viewed as attractive drug candidates for the targeted therapy of this malignancy. However, the exact contribution of MEK1 and MEK2 to the pathogenesis of colorectal cancer remains to be established.</p> <p>Methods</p> <p>Wild type and constitutively active forms of MEK1 and MEK2 were ectopically expressed by retroviral gene transfer in the normal intestinal epithelial cell line IEC-6. We studied the impact of MEK1 and MEK2 activation on cellular morphology, cell proliferation, survival, migration, invasiveness, and tumorigenesis in mice. RNA interference was used to test the requirement for MEK1 and MEK2 function in maintaining the proliferation of human colorectal cancer cells.</p> <p>Results</p> <p>We found that expression of activated MEK1 or MEK2 is sufficient to morphologically transform intestinal epithelial cells, dysregulate cell proliferation and induce the formation of high-grade adenocarcinomas after orthotopic transplantation in mice. A large proportion of these intestinal tumors metastasize to the liver and lung. Mechanistically, activation of MEK1 or MEK2 up-regulates the expression of matrix metalloproteinases, promotes invasiveness and protects cells from undergoing anoikis. Importantly, we show that silencing of MEK2 expression completely suppresses the proliferation of human colon carcinoma cell lines, whereas inactivation of MEK1 has a much weaker effect.</p> <p>Conclusion</p> <p>MEK1 and MEK2 isoforms have similar transforming properties and are able to induce the formation of metastatic intestinal tumors in mice. Our results suggest that MEK2 plays a more important role than MEK1 in sustaining the proliferation of human colorectal cancer cells.</p