Influence of response prepotency strength, general working memory resources, and specific working memory load on the ability to inhibit predominant responses: A comparison of young and elderly participants

One conception of inhibitory functioning suggests that the ability to successfully inhibit a predominant response depends mainly on the strength of that response, the general functioning of working memory processes, and the working memory demand of the task (Roberts, Hager, and Heron, 1994). The proposal that inhibition and functional working memory capacity interact was assessed in the present study using two motor inhibition tasks (Go/No-Go and response incompatibility) in young and older participants. The strength of prepotency was assessed with a short or long training phase for the response to be inhibited. The influence of working memory resources was evaluated by administering the tasks in full versus divided attention conditions. The effect of working memory load was manipulated by increasing the number of target and distracter items in each task. Results showed no effect of prepotency strength, whereas dividing attentional resources and increasing working memory load were associated with greater inhibitory effects in both groups and for both tasks. This deleterious effect was higher for older participants, except in the working memory load condition of the Go/No-Go task. These results suggest an interactive link between working memory and response inhibition by showing that taxing working memory resources increases the difficulty of inhibiting prepotent responses in younger and older subjects. The additional detrimental effect of these factors on healthy elderly subjects was related to their decreased cognitive resources and to their shorter span size

Mechatronics Approach for the Development of a Nano-Active-Stabilization-System

With the growing number of fourth generation light sources, there is an increased need of fast positioning end-stations with nanometric precision. Such systems are usually including dedicated control strategies, and many factors may limit their performances. In order to design such complex systems in a predictive way, a mechatronic design approach also known as "model based design", may be utilized. In this paper, we present how this mechatronic design approach was used for the development of a nano-hexapod for the ESRF ID31 beamline. The chosen design approach consists of using models of the mechatronic system (including sensors, actuators and control strategies) to predict its behavior. Based on this behavior and closed-loop simulations, the elements that are limiting the performances can be identified and re-designed accordingly. This allows to make adequate choices concerning the design of the nano-hexapod and the overall mechatronic architecture early in the project and save precious time and resources. Several test benches were used to validate the models and to gain confidence on the predictability of the final system's performances. Measured nano-hexapod's dynamics was shown to be in very good agreement with the models. Further tests should be done in order to confirm that the performances of the system match the predicted one. The presented development approach is foreseen to be applied more frequently to future mechatronic system design at the ESRF.NAS

Association between lumbar disc degeneration and biochemical markers of bone and cartilage remodelling

peer reviewe

Parathyroid hormone plasma concentrations in response to low 25-OH vitamin D circulating levels increases with age in elderly women.

Peer reviewe

SURFACE ENGINEERING FOR PARTS MADE BY ADDITIVE MANUFACTURING

peer reviewedthe surface preparation of metal parts made by additive manufacturing (AM). AM is a technology of choice for manufacturing of parts with complex shapes (heat exchangers, RF supports, optical parts…) and integrated functions such as conformal cooling channels, clips, hinges, etc. This opens the door for lightweight parts which are of prime importance for space applications. The potential of the AM technologies is however impeded by the quite rough surface finish that is observed on the as-manufactured parts. It is known that such a finish is likely to impact the performance of the parts. Several post-treatment techniques can be applied to improve the surface condition of the AM parts. However, so far, the influence of the successive post-processing steps on the final properties is not well established. Therefore, a better understanding of the impact of surface characteristics on the material behaviour is needed to expand the use of AM for high performance parts. The objective of this study, supported by ESA, is to propose and evaluate various surface finishing techniques for parts made by the AM technologies, in order to check their compatibility, evaluate their properties and derive guidelines for future applications. CRM is the prime proposer of this study and is in charge of the surface treatment and characterisations. Sirris additive manufacturing facilities are used to produce the parts. Thales Alenia Space and Walopt are included into the industrial team to provide concrete application cases. The study focuses on metals. Two metals under study are presented here: AlSi10Mg and Ti6Al4V. This paper is devoted to the early results of the first steps of surface preparation, namely material removal from the surface of the produced parts in order to improve their surface properties. As a first phase, tribo-finishing (TF) is tested on prototype parts to check its capabilities. Surface and volume parameters are analyzed, namely achieved roughness, material removal rate, location of removed material. The limitations in terms of geometry and applicability are discussed as well. These first observations should serve as guidelines for further application of AM for the design of parts used in space industry

Effect on bone turnover markers of once-yearly intravenous infusion of zoledronic acid versus daily oral risedronate in patients treated with glucocorticoids

Objective. Long-term glucocorticoid use is accompanied by rapid bone loss; however, early treatment with bisphosphonates prevents bone loss and reduces fracture risk. The aim of this study was to examine the effects of two bisphosphonates, i.v. zoledronic acid (ZOL) versus oral risedronate (RIS), on bone turnover markers (BTMs) in subjects with glucocorticoid-induced osteoporosis (GIO). Methods. Patients were randomly stratified according to the duration of pre-study glucocorticoid therapy [prevention subpopulation (ZOL, n = 144; RIS, n = 144) ≤3 months, treatment subpopulation (ZOL, n = 272; RIS, n = 273) >3 months]. Changes in β-C-terminal telopeptides of type 1 collagen (β-CTx), N-terminal telopeptide of type I collagen (NTx), procollagen type 1 N-terminal propeptide (P1NP) and bone-specific alkaline phosphatase (BSAP) from baseline were measured on day 10 and months 3, 6 and 12. Results. At most time points, there were significantly greater reductions (P < 0.05) in the concentrations of serum β-CTx, P1NP and BSAP and urine NTx in subjects on ZOL compared with RIS in both males and females of the treatment and prevention subpopulations. In pre- and post-menopausal women, there were significantly greater reductions in the concentrations of BTMs with ZOL compared with RIS. At 12 months, ZOL had significantly greater reductions compared with RIS (P < 0.05) for β-CTx, P1NP, BSAP and NTx levels, independent of glucocorticoid dose. Conclusions. Once-yearly i.v. infusion of ZOL 5 mg was well tolerated in different subgroups of GIO patients. ZOL was non-inferior to RIS and even superior to RIS in the response of BTMs in GIO patients. Trial registration: ClinicalTrials.gov, http://clinicaltrials.gov, NCT0010062

Platelet-rich plasma to treat jumper’s knee: preliminary results

peer reviewedIntroduction: Tendinopathies, especially jumper’s knee, often remain rebel to conservative treatments. Several experimental studies have shown the healing properties of platelet and their growth factors. Researches have specifically demonstrated the platelets action as mediator and/or enhancer of tissue healing. The aim of our study was to investigate the effect of 1 injection of PRP in patients suffering from chronic jumper’s knee. Our protocol was approved by Ethic Committee of University and University Hospital of Liège. Methods: Patients performed imaging (US and MRI) and functional assessments, and a clinical examination using an algometer, before treatment and 6 weeks after PRP treatment. They were also invited to answer to questionnaire relative to pain and functional status. PRP was obtained from autologous blood using an apheresis system (COM.TEC, Fresenius). The injection of 6mL of PRP was realised without local anaesthesia into the proximal insertion of the patellar tendon. A 48h rest-time was recommended after infiltration. Afterwards, a submaximal eccentric reeducation was initiated 1 week after infiltration 3 times a week during 5 weeks. In case of pain, anti-inflammatory drugs were prohibited and patient were encouraged to take class I or II painbrakers. Results: At this time, 10 patients with jumper’s knee were included in our study. Pre-injection tests revealed pain of the upper part of the patellar tendon just below the patella, associated with loss of function. Imaging exams confirmed diagnosis. Six weeks post-injection, the clinical status was improved in all patients, with a significant decrease of algo-functional scores. The pain reported during functional assessments was decreased (in particular for the eccentric actions), yet no significant improvement of physical performances was observed. We found no significant differences between imaging exams before and 6 weeks after PRP injection. Conclusion: One in situ injection of PRP clinically improved patients with jumper’s knee 6 weeks after treatment. All the 10 patients reported a decrease of pain during day-life and through physical activities. However nor functional performances neither imaging were improved

Progression in MCF-7 Breast Cancer Cell Tumorigenicity: Compared Effect of FGF-3 and FGF-4.

The transforming properties of fibroblast growth factor 3 (FGF-3) were investigated in MCF7 breast cancer cells and compared to those of FGF-4, a known oncogenic product. The short form of fgf-3 and the fgf-4 sequences were each introduced with retroviral vectors and the proteins were only detected in the cytoplasm of the infected cells, as expected. In vitro, cells producing FGF-3 (MCF7.fgf-3) and FGF-4 (MCF7.fgf-4) displayed an amount of estrogen receptors decreased to around 45% of the control value. However, MCF7.fgf-3 cell proliferation remained responsive to estradiol supply. The sensitivity of the MCF7.fgf-4 cells, if existant, was masked by the important mitogenic action exerted by FGF-4. In vivo, the MCF7.fgf-3 and MCF7.fgf-4 cells gave rise to tumors under conditions in which the control cells were not tumorigenic. Supplementing the mice with estrogen had the paradoxical effect of totally suppressing the start of the FGF-3 as well as the FGF-4 tumors. Tumorigenicity in the presence of matrigel was similar for MCF7.fgf-3 and control cells and was increased by estrogen supplementation. Once started, the MCF7.fgf-4 tumors grew with a characteristic high rate. Remarkably, FGF-4 but not FGF-3, stimulated the secretion of vascular endothelial growth factor (VEGF165) without altering the steady-state level of its mRNA, suggesting a possible regulation of VEGF synthesis at the translational level in MCF7 cells. The increased VEGF secretion is probably involved in the more aggressive phenotype of the MCF7.fgf-4 cells while a decreased dependence upon micro-environmental factors might be part of the increased tumorigenic potential of the MCF7.fgf-3 cells.Peer reviewe