La sédentarité est un facteur de risque de mortalité chez les patients en hémodialyse chronique, mais le niveau d’activité physique est peu étudié dans cette population. Plusieurs études ont évalué ...l’activité physique par des méthodes subjectives basées sur des questionnaires. Notre travail avait pour objectif de mesurer le niveau d’activité physique par le recueil du nombre de pas quotidiens à l’aide d’un podomètre et de déterminer les facteurs impliqués dans la réduction de l’activité physique.
C’est une étude transversale en simple aveugle ayant inclue quarante-trois hémodialysés chroniques. L’activité physique a été évaluée à l’aide d’un podomètre (podomètre multifonction modèle ONWALK 900, GEONAUTE) en enregistrant quotidiennement le nombre de pas pendant sept jours consécutifs.
Quarante-trois patients étaient colligés d’âge médian de 56 ans 40–68, avec une prédominance masculine sexe ratio H/F : 1,26. L’activité physique médiane était de 4769 pas/jour 1597–8364. Le niveau d’activité physique était au-dessous du niveau recommandé (10 000 pas/jour) chez 90,7 % des patients et 51,2 % étaient considérés comme sédentaires (<5000 pas/jour). L’activité physique était plus faible les jours de dialyse que les jours de non dialyse mais de façon non significative (4052 vs 4982 pas/jour). Les patients ont été répartis en deux groupes en fonction du nombre de pas quotidien : un groupe <5000 et un groupe >5000. En analyse univariée, les patients du groupe<5000 étaient de sexe féminin, plus âgés, obèses et avaient un taux plus bas d’albumine et de créatinine sérique au branchement. En analyse multivariée, seuls l’âge et le sexe féminin étaient significativement associés à la sédentarité. Cette enquête souligne le faible niveau d’activité physique de nos patients hémodialysés dont la moitié était sédentaire. Les facteurs de risque de sédentarité étaient le sexe féminin et l’âge avancé. D’où l’intérêt d’une évaluation précoce de l’activité physique chez les hémodialysés chroniques et la mise en place de programmes visant à encourager l’exercice physique.
Physical inactivity is a risk factor for mortality in chronic hemodialysis patients and is poorly documented in this population. Several studies have evaluated physical activity using subjective methods based on questionnaires. Aim of our study was to record physical activity level during seven consecutive days using a pedometer to measure daily step numbers and to determine factors involved in physical activity limitation.
A cross-sectional single-blind study including forty-three chronic hemodialysis patients was performed. Physical activity was recorded using a using a pedometer (multifunction pedometer model ONWALK 900, GEONAUTE) to measure daily step numbers during seven consecutive days.
Forty-three patients were included. Their median age was 56 40–68 years with male predominance sex ratio M/F : 1.26. Median physical activity was 4769 steps/day 1597–8364. Physical activity level was below the recommended level (10,000 steps/day) in 90.7 % of patients and 51.2 % were considered sedentary (<5000 steps/day). Physical activity was lower on dialysis compared with non-dialysis days, but the difference is not significant (4052 vs 4982 steps/day). Patients were separated into two groups according to daily step numbers : a group<5000 and a group>5000. In univariate analysis, patients <5000 were women, older, obese and had lower serum albumin and serum creatinine levels. In multivariate analysis, only age and female sex were significantly associated with sedentary lifestyle. This survey confirms that hemodialysis patients present with a very low physical activity level. A higher risk of sedentary was identified in older women. Hence the value of an early assessment of physical activity in chronic hemodialysis patients and the establishment of programs to encourage exercise.
A combination of latent and sensible heat capabilities has made phase change materials (PCMs) very useful in a variety of heat transfer applications. The main purpose of using the phase change ...material in lithium-ion (Li-ion) battery thermal management systems (BTMs) is to mitigate the excessive temperature rise in the cells and to create uniform temperature distribution within the battery pack. In this work, carbon fibers were added to a PCM to enhance its heat transfer potentials. Various strategies were adopted to manage temperature distribution around a single AA-battery-like simulator. The effects of carbon fiber size and weight percent within the PCM on thermal performance were studied. Experimental results have indicated that a mixture of PCM with 2-mm-long carbon fibers and mass percentage of 0.46% showed the best thermal performance for which the maximum temperature rise in the battery simulator can be reduced by up to 45%.
The schematic of the experimental setup and data acquisition system (1-power source 2-container 3-battery module 4-thermocouples 5-temperature indicator 6-data acquisition system). Display omitted
•Thermal performance of a Li-ion battery simulator is studied in the presence of PCM.•The effect of carbon fiber on heat transfer enhancement is examined.•Better thermal management can be achieved by the presence of carbon fiber in PCM.•Both carbon fiber mass fraction and length play crucial role in thermal management.
Silica aerogel (SA) is considered one of the most promising thermal insulation materials due to its nano-size open pore structure. In this study, one part room temperature vulcanized silicone rubber ...(RTV-SiR) composite with improved thermal performance has been produced simply by incorporating SA as filler. Hydrophobic SA particles of 0.5 mm with a surface area of ∼700 m2/g and density of 0.07 g/cm3 were prepared from rice husk ash via ambient pressure drying. The RTV-SiR composite of 5.0 mm thickness was prepared by blending with 9 wt% of SA particles using a mechanical mixer and kept for vulcanization at room temperature. The properties of the RTV-SiR composite were systematically investigated using scanning electron microscopy (SEM), tensile test, surface roughness, water contact angle measurement, Fourier transform infrared spectroscopy (FTIR), hot-disk thermal conductivity analyzer, thermogravimetric analysis (TGA) and flame penetration test. Compared to pristine RTV-SiR, composite reinforced with SA particles demonstrates low density, high strength and specific modulus, low thermal conductivity, high surface hydrophobicity and excellent resistance to flame penetration test. The composite can withstand the penetration of the butane flame torch for more than 800 s and keep the unexposed side temperature (plateau of 100 °C) below the decomposition temperature of the SiR. The results suggest that the thermal performance of the composite is strongly influenced by the physical properties of the SA and the structural integrity of the SA in the composite. The SA reinforced SiR composite has a potential application prospect in building insulation and fire protection.
Display omitted
•Hydrophobic SA (0.035 W/mK) was produced from RHA via ambient drying.•Incorporation of SA in RTV-SiR had significant effects on specific strength and thermal conductivity.•The composite demonstrates self-cleaning capability and excellent resistance to flame penetration test.•The SA filler acts as barrier for heat and mass transport depending on its structural integrity in the composite.•This proof-of-concept broadens the potential of SA based composites in thermal insulation application.
•The article provides a summary on cellular receptors involved in virus immunity.•It summarizes key findings on viroporins, a novel class of viral proteins and their role in the virus life cycle and ...host cell interactions.•It presents an overview of the current understanding of inflammasomes complex activation, with special focus on NLRP3.•It discusses the correlation between viroporins and inflammasomes activation and aggravated inflammatory cytokines production.
Viroporins are virus encoded proteins that alter membrane permeability and can trigger subsequent cellular signals. Oligomerization of viroporin subunits results in formation of a hydrophilic pore which facilitates ion transport across host cell membranes. These viral channel proteins may be involved in different stages of the virus infection cycle. Inflammasomes are large multimolecular complexes best recognized for their ability to control activation of caspase-1, which in turn regulates the maturation of interleukin-1 β (IL-1β) and interleukin 18 (IL-18). IL-1β was originally identified as a pro-inflammatory cytokine able to induce both local and systemic inflammation and a febrile reaction in response to infection or injury. Excessive production of IL-1β is associated with autoimmune and inflammatory diseases. Microbial derivatives, bacterial pore-forming toxins, extracellular ATP and other pathogen-associated molecular patterns trigger activation of NLRP3 inflammasomes. Recent studies have reported that viroporin activity is capable of inducing inflammasome activity and production of IL-1β, where NLRP3 is shown to be regulated by fluxes of K+, H+ and Ca2+ in addition to reactive oxygen species, autophagy and endoplasmic reticulum stress. The aim of this review is to present an overview of the key findings on viroporin activity with special emphasis on their role in virus immunity and as possible activators of inflammasomes.
There are several physical, chemical and biological methods to treat petroleum pollutants. Moving bed biofilm reactor is a biological process for treatment of these pollutants. In this research, ...moving bed biofilm reactor has been selected owing to its eco-friendly features and because of its high efficiency in removing these pollutants. In this study, for the first time, serial moving bed biofilm reactor was introduced and used to remove petroleum pollutants from wastewater. In this biological system, two moving bed biofilm reactors were connected. Feed forward and feed backward systems were used for this connection. Also, in this research, the response surface methodology was used to model the removal efficiency of petroleum pollutants in serial moving bed biofilm reactor. The optimal operation conditions were obtained by examining three effective independent parameters: retention time (11.23–34.77 h), influent total petroleum hydrocarbon concentration (164.78–585.22 mg/L), and media filling ratio (28.18–61.82%). The results of the study showed that decreasing influent total petroleum hydrocarbon concentration and increasing retention time and media filling ratio led to a decline in the food to microorganism ratio, and thereby improved removal efficiency of pollutants. The experiments showed that retention time of 23 h, influent total petroleum hydrocarbon of 164.78 mg/L, and media filling ratio of 45% yielded the highest efficiency of 97% in removing petroleum pollutants. This high efficiency under optimal conditions makes it possible to use serial moving bed biofilm reactors for petroleum wastewater treatment.
PDF
