WTC2005-64215 MULTI SCALE STUDY OF ABRASION SIGNATURE BY 2D WAVELET DECOMPOSITION

Abstract The high performance of industrial applications, requires increasingly technical functional surfaces, particulary from the point of view of topography and microtexture. To study the effect of abrasive finishing in a wide range of wavelengths of surface topography, we developed a multi-scale approach, based on the decomposition of surface topography by 2D continuous wavelet transform. This new approach made it possible to determine the multi-scale transfer function of machining by abrasion for each stage of finishing. The methodology can be extended to characterize abrasive wear in a wide range of scales. Introduction The use of hard turning as a finishing process is often limited by surface quality requirements in the case of component surfaces designed to support high stress. Low roughness can be achieved only at low feed rates. Moreover, tool wear leads to a deterioration in the surface after the tool has been in use for some time. A subsequent finishing operation can both increase the range of permissible feed rates towards higher values and prolong the life of the tool's cutting edge. One finishing operation whose working principle suits especially well for combination with hard turning is the belt grinding. This abrasive operation makes it possible to create surfaces of high quality, with specific functions like mechanical bearing pressure, sealing of metal joints, friction and noise of friction. Abrasive finishing modifies the surface topography in a wide range of scales of roughness and waviness, and consequently modifies the functionality of the surface in terms of bearing area, local plasticity and durability. This paper introduces a new approach based on a multi-scale decomposition of the surface topography before and after finishing by using a 2D continuous wavelet decomposition. This approach makes it possible to follow the effect of the various stages of finishing on a wide range of wavelengths, and makes it possible to determine th

Preliminary Investigation of the Frictional Response of Reptilian Shed Skin

Developing deterministic surfaces relies on controlling the structure of the rubbing interface so that not only the surface is of optimized topography, but also is able to self-adjust its tribological behaviour according to the evolution of sliding conditions. In seeking inspirations for such designs, many engineers are turning toward the biological world to correlate surface structure to functional behavior of bio-analogues. From a tribological point of view, squamate reptiles offer diverse examples where surface texturing, submicron and nano-scale features, achieve frictional regulation. In this paper, we study the frictional response of shed skin obtained from a snake (Python regius). The study employed a specially designed tribo-acoustic probe capable of measuring the coefficient of friction and detecting the acoustical behavior of the skin in vivo. The results confirm the anisotropy of the frictional response of snakes. The coefficient of friction depends on the direction of sliding: the value in forward motion is lower than that in the backward direction. In addition it is shown that the anisotropy of the frictional response may stem from profile asymmetry of the individual fibril structures present within the ventral scales of the reptil

Experimental study of the contribution of gear tooth finishing processes to friction noise

Micro geometry of a gear tooth influences the contact durability and wear performance. In this paper, different gear tooth flanks have been manufactured by different finishing processes, which were then characterized using multiscale surface analysis, based on wavelet transform. The friction noise was then measured before and after meshing in dry and lubricated conditions, to quantify the acoustic performance of the surfaces. To accomplish this objective, a new non-destructive sensory measurement technique was developed to characterize the friction noise generated by teeth flank surface. Results show the ability of the new method to discriminate functional behavior of different surfaces as well as give possible explanations as to the contribution of tooth flank asperities during the meshing on the gear in terms of gear noise performances

International prospective observational study on intracranial pressure in intensive care (ICU): the SYNAPSE-ICU study protocol.

Intracranial pressure (ICP) monitoring is commonly used in neurocritical care patients with acute brain injury (ABI). Practice about indications and use of ICP monitoring in patients with ABI remains, however, highly variable in high-income countries, while data on ICP monitoring in low and middle-income countries are scarce or inconsistent. The aim of the SYNAPSE-ICU study is to describe current practices of ICP monitoring using a worldwide sample and to quantify practice variations in ICP monitoring and management in neurocritical care ABI patients. The SYNAPSE-ICU study is a large international, prospective, observational cohort study. From March 2018 to March 2019, all patients fulfilling the following inclusion criteria will be recruited: age >18 years; diagnosis of ABI due to primary haemorrhagic stroke (subarachnoid haemorrhage or intracranial haemorrhage) or traumatic brain injury; Glasgow Coma Score (GCS) with no eye opening (Eyes response=1) and Motor score ≤5 (not following commands) at ICU admission, or neuro-worsening within the first 48 hours with no eye opening and a Motor score decreased to ≤5. Data related to clinical examination (GCS, pupil size and reactivity, Richmond Agitation-Sedation Scale score, neuroimaging) and to ICP interventions (Therapy Intensity Levels) will be recorded on admission, and at day 1, 3 and 7. The Glasgow Outcome Scale Extended (GOSE) will be collected at discharge from ICU and from hospital and at 6-month follow-up. The impact of ICP monitoring and ICP-driven therapy on GOSE will be analysed at both patient and ICU level. The study has been approved by the Ethics Committee 'Brianza' at the Azienda Socio Sanitaria Territoriale (ASST)-Monza (approval date: 21 November 2017). Each National Coordinator will notify the relevant ethics committee, in compliance with the local legislation and rules. Data will be made available to the scientific community by means of abstracts submitted to the European Society of Intensive Care Medicine annual conference and by scientific reports and original articles submitted to peer-reviewed journals. NCT03257904

Compensatory-reserve-weighted intracranial pressure versus intracranial pressure for outcome association in adult traumatic brain injury: a CENTER-TBI validation study

Background: Compensatory-reserve-weighted intracranial pressure (wICP) has recently been suggested as a supplementary measure of intracranial pressure (ICP) in adult traumatic brain injury (TBI), with a single-center study suggesting an association with mortality at 6 months. No multi-center studies exist to validate this relationship. The goal was to compare wICP to ICP for association with outcome in a multi-center TBI cohort. Methods: Using the Collaborative European Neuro Trauma Effectiveness Research in TBI (CENTER-TBI) high-resolution intensive care unit (ICU) cohort, we derived ICP and wICP (calculated as wICP = (1 12 RAP) 7 ICP; where RAP is the compensatory reserve index derived from the moving correlation between pulse amplitude of ICP and ICP). Various univariate logistic regression models were created comparing ICP and wICP to dichotomized outcome at 6 to 12 months, based on Glasgow Outcome Score\u2014Extended (GOSE) (alive/dead\u2014GOSE 65 2/GOSE = 1; favorable/unfavorable\u2014GOSE 5 to 8/GOSE 1 to 4, respectively). Models were compared using area under the receiver operating curves (AUC) and p values. Results: wICP displayed higher AUC compared to ICP on univariate regression for alive/dead outcome compared to mean ICP (AUC 0.712, 95% CI 0.615\u20130.810, p = 0.0002, and AUC 0.642, 95% CI 0.538\u2013746, p < 0.0001, respectively; no significant difference on Delong\u2019s test), and for favorable/unfavorable outcome (AUC 0.627, 95% CI 0.548\u20130.705, p = 0.015, and AUC 0.495, 95% CI 0.413\u20130.577, p = 0.059; significantly different using Delong\u2019s test p = 0.002), with lower wICP values associated with improved outcomes (p < 0.05 for both). These relationships on univariate analysis held true even when comparing the wICP models with those containing both ICP and RAP integrated area under the curve over time (p < 0.05 for all via Delong\u2019s test). Conclusions: Compensatory-reserve-weighted ICP displays superior outcome association for both alive/dead and favorable/unfavorable dichotomized outcomes in adult TBI, through univariate analysis. Lower wICP is associated with better global outcomes. The results of this study provide multi-center validation of those seen in a previous single-center study

Univariate comparison of performance of different cerebrovascular reactivity indices for outcome association in adult TBI: a CENTER-TBI study

Background: Monitoring cerebrovascular reactivity in adult traumatic brain injury (TBI) has been linked to global patient outcome. Three intra-cranial pressure (ICP)-derived indices have been described. It is unknown which index is superior for outcome association in TBI outside previous single-center evaluations. The goal of this study is to evaluate indices for 6- to 12-month outcome association using uniform data harvested in multiple centers. Methods: Using the prospectively collected data from the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study, the following indices of cerebrovascular reactivity were derived: PRx (correlation between ICP and mean arterial pressure (MAP)), PAx (correlation between pulse amplitude of ICP (AMP) and MAP), and RAC (correlation between AMP and cerebral perfusion pressure (CPP)). Univariate logistic regression models were created to assess the association between vascular reactivity indices with global dichotomized outcome at 6 to 12 months, as assessed by Glasgow Outcome Score\u2013Extended (GOSE). Models were compared via area under the receiver operating curve (AUC) and Delong\u2019s test. Results: Two separate patient groups from this cohort were assessed: the total population with available data (n = 204) and only those without decompressive craniectomy (n = 159), with identical results. PRx, PAx, and RAC perform similar in outcome association for both dichotomized outcomes, alive/dead and favorable/unfavorable, with RAC trending towards higher AUC values. There were statistically higher mean values for the index, % time above threshold, and hourly dose above threshold for each of PRx, PAx, and RAC in those patients with poor outcomes. Conclusions: PRx, PAx, and RAC appear similar in their associations with 6- to 12-month outcome in moderate/severe adult TBI, with RAC showing tendency to achieve stronger associations. Further work is required to determine the role for each of these cerebrovascular indices in monitoring of TBI patients

Correction to: Serum sodium and intracranial pressure changes after desmopressin therapy in severe traumatic brain injury patients : a multi-centre cohort study

Following publication of the original article [1], we were notified that the collaborators’ names part of the “The TBI Collaborative” group has not been indexed in Pubmed. Below the collaborators names full list

How do 66 European institutional review boards approve one protocol for an international prospective observational study on traumatic brain injury? Experiences from the CENTER-TBI study

Background The European Union (EU) aims to optimize patient protection and efficiency of health-care research by harmonizing procedures across Member States. Nonetheless, further improvements are required to increase multicenter research efficiency. We investigated IRB procedures in a large prospective European multicenter study on traumatic brain injury (TBI), aiming to inform and stimulate initiatives to improve efficiency. Methods We reviewed relevant documents regarding IRB submission and IRB approval from European neurotrauma centers participating in the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI). Documents included detailed information on IRB procedures and the duration from IRB submission until approval(s). They were translated and analyzed to determine the level of harmonization of IRB procedures within Europe. Results From 18 countries, 66 centers provided the requested documents. The primary IRB review was conducted centrally (N = 11, 61%) or locally (N = 7, 39%) and primary IRB approval was obtained after one (N = 8, 44%), two (N = 6, 33%) or three (N = 4, 23%) review rounds with a median duration of respectively 50 and 98 days until primary IRB approval. Additional IRB approval was required in 55% of countries and could increase duration to 535 days. Total duration from submission until required IRB approval was obtained was 114 days (IQR 75-224) and appeared to be shorter after submission to local IRBs compared to central IRBs (50 vs. 138 days, p = 0.0074). Conclusion We found variation in IRB procedures between and within European countries. There were differences in submission and approval requirements, number of review rounds and total duration. Research collaborations could benefit from the implementation of more uniform legislation and regulation while acknowledging local cultural habits and moral values between countries.Peer reviewe

Compensatory-reserve-weighted intracranial pressure versus intracranial pressure for outcome association in adult traumatic brain injury: a CENTER-TBI validation study

BackgroundCompensatory-reserve-weighted intracranial pressure (wICP) has recently been suggested as a supplementary measure of intracranial pressure (ICP) in adult traumatic brain injury (TBI), with a single-center study suggesting an association with mortality at 6months. No multi-center studies exist to validate this relationship. The goal was to compare wICP to ICP for association with outcome in a multi-center TBI cohort.MethodsUsing the Collaborative European Neuro Trauma Effectiveness Research in TBI (CENTER-TBI) high-resolution intensive care unit (ICU) cohort, we derived ICP and wICP (calculated as wICP=(1-RAP)xICP; where RAP is the compensatory reserve index derived from the moving correlation between pulse amplitude of ICP and ICP). Various univariate logistic regression models were created comparing ICP and wICP to dichotomized outcome at 6 to 12months, based on Glasgow Outcome ScoreExtended (GOSE) (alive/deadGOSE 2/GOSE=1; favorable/unfavorableGOSE 5 to 8/GOSE 1 to 4, respectively). Models were compared using area under the receiver operating curves (AUC) and p values.ResultswICP displayed higher AUC compared to ICP on univariate regression for alive/dead outcome compared to mean ICP (AUC 0.712, 95% CI 0.615-0.810, p=0.0002, and AUC 0.642, 95% CI 0.538-746, p<0.0001, respectively; no significant difference on Delong's test), and for favorable/unfavorable outcome (AUC 0.627, 95% CI 0.548-0.705, p=0.015, and AUC 0.495, 95% CI 0.413-0.577, p=0.059; significantly different using Delong's test p=0.002), with lower wICP values associated with improved outcomes (p<0.05 for both). These relationships on univariate analysis held true even when comparing the wICP models with those containing both ICP and RAP integrated area under the curve over time (p<0.05 for all via Delong's test).ConclusionsCompensatory-reserve-weighted ICP displays superior outcome association for both alive/dead and favorable/unfavorable dichotomized outcomes in adult TBI, through univariate analysis. Lower wICP is associated with better global outcomes. The results of this study provide multi-center validation of those seen in a previous single-center study