Analyse des capacités d’agir d’un syndicat local en matière de prise en charge des risques psychosociaux au travail : une étude de cas dans le secteur de la métallurgie au Québec

En cette ère d’hypertravail (Charest et Rhéaume, 2008) menant à une plus grande charge de travail, les travailleurs souffrent. Malgré cela, peu d’études ont abordé la question de la prise en charge de la santé mentale au travail dans une perspective syndicale. Nous avons ainsi approfondi nos connaissances sur les initiatives syndicales de prise en charge des risques psychosociaux (RPS) au Québec. Ce mémoire cherche donc à répondre à la question de recherche : comment se façonnent les capacités d’agir d’un syndicat local en matière de prise en charge des risques psychosociaux au travail? Pour y répondre, nous avons utilisé plusieurs écrits portant sur les ressources de pouvoir à la disposition des syndicats, les cadres identitaires et les ressources normatives pouvant venir influencer les capacités d’agir des syndicats en matière de prise en charge des risques psychosociaux. En plus de ces écrits, nous avons aussi porté une attention sur l’influence que peut exercer la collaboration patronale-syndicale sur le développement des capacités d’agir des syndicats. Nos données de recherche ont été amassées grâce à une étude de cas, où nous avons fait 8 entretiens semi-dirigés auprès d’un syndicat local affilié à la FTQ dans le secteur de la métallurgie au Québec. Nos résultats démontrent que certaines ressources et certains éléments des cadres identitaires exercent une influence positive sur les capacités d’agir du syndicat en matière de prise en charge des RPS : le réseautage externe et les intérêts partagés par le groupe de référence et le groupe d’opposition. Toutefois, les ressources et les éléments des cadres identitaires exercent une influence négative sur les capacités d’agir du syndicat en matière de prise en charge des RPS : nous pensons au projet syndical et aux ressources organisationnelles.In this era of hyper-work (Charest and Rhéaume, 2008) leading to a greater workload and a strong subjective investment at work, workers are suffering. Despite this, few studies have addressed the issue of managing mental health in the workplace from a trade union perspective. We have thus deepened our knowledge of union initiatives for the management of psychosocial risks (PSR) in Quebec. This thesis therefore seeks to answer the research question: how are the capacities of a local union to act in terms of taking charge of psychosocial risks at work? To answer this, we used several writings on the power resources available to unions, identity frameworks and normative resources that can influence the development of unions' capacities to act in terms of taking charge of psychosocial risks. In addition to these writings, we also paid attention to the influence that labour-management collaboration can exert on the development of union capacities to act. Our research data was gathered through a case study, where we conducted 8 semi-structured interviews with a local union affiliated with the FTQ in the metallurgy sector in Quebec. Our results show that certain resources and certain elements of identity frameworks have a positive influence on the union's capacities to act in terms of taking charge of PSR: external networking and the interests shared by the reference group and the group of opposition. However, certain resources and elements of identity frameworks have a negative influence on the union’s capacity to act in terms of taking charge of RPS: we are thinking of the union project and organizational resources

Process economical effects of implementation of ready-to-use micro carriers in cell- based virus vaccine production

Micro-carriers are used as support for the growth of adherent cells. By providing a large cultivation surface in bioreactor cultures, micro-carriers have replaced, to a great extent, cultivation in Cell Factory™ systems or roller bottles over the last decades. At Sanofi Pasteur, one of the world leaders in human vaccines, Cytodex™ 1 microcarriers have been used in the production of viral vaccines on Vero cells for several years. In accordance with the supplier’s recommendation, the microcarriers that are delivered dry are swollen in buffer, washed, and heat-sterilized before use. Since October 2016 a ready-to-use Cytodex™ 1 alternative, delivered presterilized by gamma irradiation, is available. Before implementing the change, the presterilized alternative was first evaluated with regards to reduced preparation time and cost. With a two-year shelf-life, the presterilized alternative reduced utility cost and added flexibility to operations by decreasing the need for steam and stainless steel materials in viral production facilities, and in alignment with extended use of single-use bioreactors equipment. The second step was to compare the cell growth and viral productivity using this ready-to-use alternative with that of the prior referenced product in place. Both cell growth and viral productivity were comparable between the two products, which supported further the documentation for the implementation of this ready-to-use alternative in GMP manufacturing for new R&D vaccine projects. The qualification process covered technical, quality, and analytical aspects based on the supplier documentation, and internal analyses and justification regarding our requirements in upstream vaccine production. While the presterilized Cytodex™ 1 microcarriers are now implemented in process development for new vaccines and qualified for manufacturing of clinical batches of new vaccine products, the next step will be to evaluate the benefits and impacts of replacing the microcarrier reference product with the gamma sterilized alternative on industrial products

Optimizing dual energy cone beam CT protocols for preclinical imaging and radiation research

Objective: The aim of this work was to investigate whether quantitative dual-energy CT (DECT) imaging is feasible for small animal irradiators with an integrated cone-beam CT (CBCT) system. Methods: The optimal imaging protocols were determined by analyzing different energy combinations and dose levels. The influence of beam hardening effects and the performance of a beam hardening correction (BHC) were investigated. In addition, two systems from different manufacturers were compared in terms of errors in the extracted effective atomic numbers (Z(eff)) and relative electron densities (rho(e)) for phantom inserts with known elemental compositions and relative electron densities. Results: The optimal energy combination was determined to be 50 and 90kVp. For this combination, Z(eff) and r rho(e) can be extracted with a mean error of 0.11 and 0.010, respectively, at a dose level of 60cGy. Conclusion: Quantitative DECT imaging is feasible for small animal irradiators with an integrated CBCT system. To obtain the best results, optimizing the imaging protocols is required. Well-separated X-ray spectra and a sufficient dose level should be used to minimize the error and noise for Z(eff) and rho(e). When no BHC is applied in the image reconstruction, the size of the calibration phantom should match the size of the imaged object to limit the influence of beam hardening effects. No significant differences in Z(eff) and rho(e) errors are observed between the two systems from different manufacturers. Advances in knowledge: This is the first study that investigates quantitative DECT imaging for small animal irradiators with an integrated CBCT system

Feasibility of CycleGAN enhanced low dose CBCT imaging for prostate radiotherapy dose calculation

Daily cone beam computed tomography (CBCT) imaging during the course of fractionated radiotherapy treatment can enable online adaptive radiotherapy but also expose patients to a non-negligible amount of radiation dose. This work investigates the feasibility of low dose CBCT imaging capable of enabling accurate prostate radiotherapy dose calculation with only 25% projections by overcoming under-sampling artifacts and correcting CT numbers by employing cycle-consistent generative adversarial networks (cycleGAN). Uncorrected CBCTs of 41 prostate cancer patients, acquired with ∼350 projections (CBCTorg), were retrospectively under-sampled to 25% dose images (CBCTLD) with only ∼90 projections and reconstructed using Feldkamp–Davis–Kress. We adapted a cycleGAN including shape loss to translate CBCTLD into planning CT (pCT) equivalent images (CBCTLD_GAN). An alternative cycleGAN with a generator residual connection was implemented to improve anatomical fidelity (CBCTLD_ResGAN). Unpaired 4-fold cross-validation (33 patients) was performed to allow using the median of 4 models as output. Deformable image registration was used to generate virtual CTs (vCT) for Hounsfield units (HU) accuracy evaluation on 8 additional test patients. Volumetric modulated arc therapy plans were optimized on vCT, and recalculated on CBCTLD_GAN and CBCTLD_ResGAN to determine dose calculation accuracy. CBCTLD_GAN, CBCTLD_ResGAN and CBCTorg were registered to pCT and residual shifts were analyzed. Bladder and rectum were manually contoured on CBCTLD_GAN, CBCTLD_ResGAN and CBCTorg and compared in terms of Dice similarity coefficient (DSC), average and 95th percentile Hausdorff distance (HDavg, HD95). The mean absolute error decreased from 126 HU for CBCTLD to 55 HU for CBCTLD_GAN and 44 HU for CBCTLD_ResGAN. For PTV, the median differences of D98%, D50% and D2% comparing both CBCTLD_GAN to vCT were 0.3%, 0.3%, 0.3%, and comparing CBCTLD_ResGAN to vCT were 0.4%, 0.3% and 0.4%. Dose accuracy was high with both 2% dose difference pass rates of 99% (10% dose threshold). Compared to the CBCTorg-to-pCT registration, the majority of mean absolute differences of rigid transformation parameters were less than 0.20 mm/0.20°. For bladder and rectum, the DSC were 0.88 and 0.77 for CBCTLD_GAN and 0.92 and 0.87 for CBCTLD_ResGAN compared to CBCTorg, and HDavg were 1.34 mm and 1.93 mm for CBCTLD_GAN, and 0.90 mm and 1.05 mm for CBCTLD_ResGAN. The computational time was ∼2 s per patient. This study investigated the feasibility of adapting two cycleGAN models to simultaneously remove under-sampling artifacts and correct image intensities of 25% dose CBCT images. High accuracy on dose calculation, HU and patient alignment were achieved. CBCTLD_ResGAN achieved better anatomical fidelity

Feasibility of automated proton therapy plan adaptation for head and neck tumors using cone beam CT images

Background: Intensity modulated proton therapy (IMPT) of head and neck (H&N) tumors may benefit from plan adaptation to correct for the dose perturbations caused by weight loss and tumor volume changes observed in these patients. As cone beam CT (CBCT) is increasingly considered in proton therapy, it may be possible to use available CBCT images following intensity correction for plan adaptation. This is the first study exploring IMPT plan adaptation on CBCT images corrected and delineated by deformable image registration of the planning CT (pCT) to the CBCT, yielding a virtual CT (vCT). Methods: A Morphons algorithm was used to deform the pCTs and corresponding delineations of 9 H&N cancer patients to a weekly CBCT acquired within +/- 3 days of a control replanning CT scan (rpCT). The IMPT treatment plans were adapted using the vCT and the adapted and original plans were recalculated on the rpCT for dose/volume parameter evaluation of the impact of adaptation. Results: On the rpCT, the adapted plans were equivalent to the original plans in terms of target volumes D-95 and V-95, but showed a significant reduction of D-2 in these volumes. OAR doses were mostly equivalent or reduced. In particular, the adapted plans did not reduce parotid gland D-mean, but the dose to the optical system. For three patients the spinal cord or brain stem received higher, though well below tolerance, maximum dose. Subsequent tightening of the treatment planning constraints for these OARs on new vCT-adapted plans did not degrade target coverage and yielded pCT equivalent plans on the vCT. Conclusions: An offline automated procedure to generate an adapted IMPT plan on CBCT images was developed and investigated. When evaluating the adapted plan on a control rpCT we observed reduced D-2 in target volumes as major improvement. OAR sparing was only partially improved by the procedure. Despite potential limitations in the accuracy of the vCT approach, an improved quality of the adapted plans could be achieved

Assessment of quantitative information for radiation therapy at a first-generation clinical photon-counting computed tomography scanner

As one of the latest developments in X-ray computed tomography (CT), photon-counting technology allows spectral detection, demonstrating considerable advantages as compared to conventional CT. In this study, we investigated the use of a first-generation clinical photon-counting computed tomography (PCCT) scanner and estimated proton relative (to water) stopping power (RSP) of tissue-equivalent materials from virtual monoenergetic reconstructions provided by the scanner. A set of calibration and evaluation tissue-equivalent inserts were scanned at 120 kVp. Maps of relative electron density (RED) and effective atomic number (EAN) were estimated from the reconstructed virtual monoenergetic images (VMI) using an approach previously applied to a spectral CT scanner with dual-layer detector technology, which allows direct calculation of RSP using the Bethe-Bloch formula. The accuracy of RED, EAN, and RSP was evaluated by root-mean-square errors (RMSE) averaged over the phantom inserts. The reference RSP values were obtained experimentally using a water column in an ion beam. For RED and EAN, the reference values were calculated based on the mass density and the chemical composition of the inserts. Different combinations of low- and high-energy VMIs were investigated in this study, ranging from 40 to 190 keV. The overall lowest error was achieved using VMIs at 60 and 180 keV, with an RSP accuracy of 1.27% and 0.71% for the calibration and the evaluation phantom, respectively

Iowa Influenza Surveillance Network: Weekly Activity Report, Weeks 40, October 8, 2016

The Iowa Influenza Surveillance Network (IISN) was established in 2004, though surveillance has been conducted at the Iowa Department of Public Health. Schools and long-term care facilities report data weekly into a Web-based reporting system. Schools report the number of students absent due to illness and the total enrolled. Long-term care facilities report cases of influenza and vaccination status of each case. Both passively report outbreaks of illness, including influenza, to IDPH

Safety and efficacy of a 6-month home-based exercise program in patients with facioscapulohumeral muscular dystrophy

Background: Previous randomized controlled trials investigating exercise training programs in facioscapulohumeral muscular dystrophy (FSHD) patients are scarce and of short duration only. This study assessed the safety and efficacy of a 6-month home-based exercise training program on fitness, muscle, and motor function in FSHD patients. Methods: Sixteen FSHD patients were randomly assigned to training (TG) and control (CG) groups (both n = 8) in a home-based exercise intervention. Training consisted of cycling 3 times weekly for 35 minutes (combination of strength, high-intensity interval, and low-intensity aerobic) at home for 24 weeks. Patients in CG also performed an identical training program (CTG) after 24 weeks. The primary outcome was change in peak oxygen uptake (VO 2 peak) measured every 6 weeks. The principal secondary outcomes were maximal quadriceps strength (MVC) and local quadriceps endurance every 12 weeks. Other outcome measures included maximal aerobic power (MAP) and experienced fatigue every 6 weeks, 6-minute walking distance every 12 weeks, and muscle characteristics from vastus lateralis biopsies taken pre- and postintervention. Results: The compliance rate was 91% in TG. Significant improvements with training were observed in the VO 2 peak (+19%, P = 0.002) and MAP by week 6 and further to week 24. Muscle endurance, MVC, and 6-minute walking distance increased and experienced fatigue decreased. Muscle fiber cross-sectional area and citrate synthase activity increased by 34% (P = 0.008) and 46% (P = 0.003), respectively. Dystrophic pathophysiologic patterns were not exacerbated. Similar improvements were experienced by TG and CTG. Conclusions: A combined strength and interval cycling exercise-training program compatible with patients' daily professional and social activities leads to significant functional benefits without compromising muscle tissue