384 research outputs found
Performance of Aged PAC Suspensions in a Hybrid Membrane Process for Drinking Water Production
RÉSUMÉ Les procédés membranaires hybrides (PMHs) allient l’usage de la filtration membranaire basse pression permettant l’enlèvement efficace des particules, y celui compris de parasites comme Cryptosporidium, à l’usage du charbon actif en poudre (CAP) pour le traitement de la contamination dissoute. Les PMHs sont une alternative prometteuse à la chaine de traitement conventionnelle, qui ne permet plus actuellement aux usines de production d’eau potable de rencontrer les normes de plus en plus sévères sur les composés dissous. Afin de diminuer les coûts opérationnels du procédé, il a été proposé de laisser vieillir le CAP dans le PMH et donc de minimiser le dosage de CAP frais. Jusqu’à présent, des études à l’échelle pilote ont mis en évidence le potentiel du PMH pour l’enlèvement de l’azote ammoniacal et du carbone organique dissous (COD) lorsqu’opéré avec de hauts temps de rétention de CAP (CAP âgé). Par contre, son potentiel à enlever les micropolluants, actuellement au centre des préoccupations des usines de traitement, reste inconnu. Il a été suggéré que l’activité bactérienne contribue de façon majeure à l’enlèvement des composés dissous lorsque l’âge du CAP est élevé (>7 jours). L’adsorption des composés dissous ne peut néanmoins être complètement écartée. Toutefois, les rôles respectifs de ces deux mécanismes pour l’enlèvement des composés dissous par le CAP âgé n’ont jamais été différenciés. Finalement, alors que l’adsorption et l’activité biologique sont deux mécanismes sensibles à la température, le potentiel du PMH en eau froide est peu connu. En conséquence, la disponibilité limitée d’information nuit à la pleine compréhension du procédé, conduisant à une opération non-optimisée du contacteur à CAP âgé dans le PMH.----------ABSTRACT Hybrid membrane processes (HMPs) couple membrane filtration with powdered activated carbon (PAC). In HMPs, low-pressure membranes ensure an efficient particle removal, including protozoan parasites such as Cryptosporidium, while the PAC contactor is devoted to the removal of dissolved compounds. Such processes are emerging as a promising alternative to conventional treatment chains, which no longer allow the drinking water facilities to comply with increasingly stringent regulations on the treated water quality. To decrease the operating costs associated with virgin PAC consumption, it was suggested to let the PAC age in the PAC contactor of the process. Until now, the potential of using aged PAC in HMPs has been demonstrated for ammonia and DOC removal, but the potential to remove micropollutants remains unknown. It is suggested that the biological activity in aged PAC contactors contributes significantly to the removal of the dissolved compounds. Yet, neither the extent of the biomass on the aged PAC, nor the residual adsorption capacity, was quantified. No study focused on discriminating the mechanisms responsible for the treatment when using aged PAC suspensions. Most of the data published on HMPs using aged PAC were gathered at pilot scale under warm water conditions, yet the efficiency of the process is most likely sensitive to temperature changes. There is currently little information available on the efficiency of HMPs under cold water conditions. This lack of information hinders the optimization of the HMP, leading to sub-optimal usage of aged PAC
Feasibility of self-rehabilitation program for upper limb after stroke in Benin
IntroductionStroke is major cause of disability and is responsible of a high cost especially in developing countries. The self-rehabilitation program constitutes a new and original treatment for stroke patients, likely to reduce the upper limb impairment and to improve activity and participation of the disabled people. The goal of this study is to evaluate the feasibility and effectiveness of a self-rehabilitation protocol in Benin.MethodsTwelve stroke chronic patients have carried out self-rehabilitation program of upper limb (3hours/day, 5 days/week for 2 weeks). The performance of these patients were evaluated before and after the self-rehabilitation program, by measuring the exercise number that patients were able to achieve during a three-hour session, and by measuring manual dexterity.ResultsTwelve patients were effectively able to complete the entire program. The number of unimanuals exercises and self-mobilization realized during a three-hour session and the score of the Box and Block Test was improved in the self-rehabilitation program (P<0.05).Discussion/conclusionSelf-rehabilitation program are feasible and are inexpensive as they do not involve a therapist. It is then a promising approach in stroke rehabilitation, particularly in developing countries, where the rehabilitation cost is usually supporting by patients
Effect of the COVID-19 pandemic lockdown on physical activity of individuals with a spinal cord injury in Belgium: observational study.
The letter reports an observational study, which our group has undertaken, to evaluate the effect of the Covid-19 lockdown among individuals with a spinal cord injury in Belgium. The primary focus of the study was the impact of the lockdown on physical activity levels, as the literature shows that individuals with a physical disability, such as spinal cord injury, particularly benefit from physical activity. The report was written in accordance to the STROBE guidelines
Age Effects on Upper Limb Kinematics Assessed by the REAplan Robotin Healthy School-Aged Children
The use of kinematics is recommended to quantitatively evaluate upper limb movements. The aims of this study were to determine the age effects on upper limb kinematics and establish norms in healthy children. Ninetythree healthy children, aged 3–12 years, participated in this study. Twenty-eight kinematic indices were computed from four tasks. Each task was performed with the REAplan, a distal effector robotic device that allows upper limb displacements in the horizontal plane. Twenty-four of the 28 indices showed an improvement during childhood. Indeed, older children showed better upper limb movements. This study was the first to use a robotic device to show the age effects on upper limb kinematics and establish norms in healthy children
Intracranial volumetric changes govern cerebrospinal fluid flow in the Aqueduct of Sylvius in healthy adults
Purpose: To characterize the intracranial volumetric changes that influence the cerebrospinal fluid (CSF) pulse in the Aqueduct of Sylvius (AoS). Materials and Methods: Neck MRI data were acquired from 12 healthy adults (8 female and 4 males; mean age=30.9 years), using a 1.5 Tesla scanner. The intracranial arterial, venous and CSF volumes changes, together with the aqueductal CSF (aCSF) volume, were estimated from flow rate data acquired at C2/C3 level and in the AoS. The correlations and temporal relationships among these volumes were computed. Results: The aCSF volumetric changes were strongly correlated (r = 0.967, p<0.001) with the changes in intracranial venous volume, whose peak occurred 7.0% of cardiac cycle (p = 0.023) before peak aCSF volume, but less correlated with the intracranial arterial and CSF volume changes (r=-0.664 and 0.676 respectively, p<0.001). The intracranial CSF volume change was correlated with the intracranial venous volume change (r=0.820, p<0.001), whose peak occurred slightly before (4.2% of CC, p=0.059). Conclusion: The aCSF pulse is strongly correlated with intracranial venous volume, with expansion of the cortical veins occurring prior to aCSF flow towards the third ventricle. Both caudal-cranial aCSF flow and venous blood retention occur when arterial blood volume is at a minimum
Gait Event Detection on Level Ground and Incline Walking Using a Rate Gyroscope
Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. Accurate determination of the Initial Contact of the foot with the floor (IC) and the final contact or Foot Off (FO) on different terrains is important. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects walking outdoors on level ground, and up and down an incline. Performance was compared with a reference pressure measurement system. The mean difference between the gyroscope and the reference was less than −25 ms for IC and less than 75 ms for FO for all terrains. Detection success was over 98%. These results provide preliminary evidence supporting the use of the gyroscope for gait event detection on inclines as well as level walking
Internal Jugular Vein Cross-Sectional Area and Cerebrospinal Fluid Pulsatility in the Aqueduct of Sylvius: A Comparative Study between Healthy Subjects and Multiple Sclerosis Patients
Objectives Constricted cerebral venous outflow has been linked with increased cerebrospinal fluid (CSF) pulsatility in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy individuals. This study investigates the relationship between CSF pulsatility and internal jugular vein (IJV) cross-sectional area (CSA) in these two groups, something previously unknown. Methods 65 relapsing-remitting MS patients (50.8% female; mean age = 43.8 years) and 74 healthy controls (HCs) (54.1% female; mean age = 43.9 years) were investigated. CSF flow quantification was performed on cine phase-contrast MRI, while IJV-CSA was calculated using magnetic resonance venography. Statistical analysis involved correlation, and partial least squares correlation analysis (PLSCA). Results PLSCA revealed a significant difference (p<0.001; effect size = 1.072) between MS patients and HCs in the positive relationship between CSF pulsatility and IJV-CSA at C5-T1, something not detected at C2-C4. Controlling for age and cardiovascular risk factors, statistical trends were identified in HCs between: increased net positive CSF flow (NPF) and increased IJV-CSA at C5-C6 (left: r = 0.374, p = 0.016; right: r = 0.364, p = 0.019) and C4 (left: r = 0.361, p = 0.020); and increased net negative CSF flow and increased left IJV-CSA at C5-C6 (r = -0.348, p = 0.026) and C4 (r = -0.324, p = 0.039), whereas in MS patients a trend was only identified between increased NPF and increased left IJV-CSA at C5-C6 (r = 0.351, p = 0.021). Overall, correlations were weaker in MS patients (p = 0.015). Conclusions In healthy adults, increased CSF pulsatility is associated with increased IJV-CSA in the lower cervix (independent of age and cardiovascular risk factors), suggesting a biomechanical link between the two. This relationship is altered in MS patients
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