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Physicochemical and Antibacterial Properties of Novel, Premixed Calcium Silicate-Based Sealer Compared to Powder–Liquid Bioceramic Sealer
No full textThe aim of this study was to compare the physicochemical properties, filling ability, and antibacterial activity of a premixed calcium silicate-based sealer to those of a powder-liquid bioceramic sealer. Ceraseal (CS) and BioRoot (BR) materials were analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy at 7 and 14 d of immersion in distilled water. The filling ability of the two sealers as well as the water contact angle, solubility, flow, roughness, crystalline microstructure, pH, and compressive strength were also evaluated. The antibacterial activity was assessed through an agar diffusion as well as through direct tests. All the results were statistically analyzed using one-way or two-way analysis of variance tests. Statistically significant lower void percentages were observed for CS at 2 and 8 mm from the working length (WL) compared to those for the BR group, whilst no significant difference was observed at 5 mm from the WL. BR sealer showed higher alkaline pH, rougher surface, lower water contact angle values, lower flowability, and higher solubility compared to CS. BR showed globular and needle-like crystalline microstructure, whilst CS had globular and flower-like crystalline microstructure up to 72 h. No statistical difference was found for the compressive strength between the two sealers. BR and CS showed no antibacterial effect against Enterococcus faecalis after 3 h, whilst both sealers showed antibacterial capacity after 24 and 72 h. BR demonstrated higher antibacterial activity after 24 h. In conclusion, the use of bioceramic sealers may play an important role in controlling bacterial growth. Moreover, CS may have superior filling ability and lower solubility than the BioRoot sealer due to its specific chemical composition and mixing method
Neighbor identity affects growth and survival of Mediterranean plants under recurrent drought
No full textInternational audienceThe increasing intensity and frequency of droughts predicted for the Mediterranean basin with ongoing climate change will impact plant communities and ecosystem functioning. This study investigated the effect of severe recurrent droughts and the role of the neighbor plant identity on the growth and survival of three abundant and co-existing species of a typical Mediterranean shrubland. Two juvenile plants, either of the same species or in all possible combinations of the two woody species Quercus coccifera and Cistus albidus and the perennial grass species Brachypodium retusum were grown together in rhizotrons under controlled watering regimes for two years. Compared to a treatment with only one drought cycle, three successive droughts reduced the relative growth rates (RGR) of shoots and roots in B. retusum, but not in woody species, and increased the mortality of the woody species, but not that of the grass. The survival of C. albidus and of B. retusum, but not of Q. coccifera, increased when the neighbor individual was a different species than when it was the same species. Our data suggest that both species composition and frequency of drought events will impact the dynamics of plant communities in Mediterranean shrublands under ongoing climate change. The abundance of dehydration sensitive woody species will likely decrease under more frequent drought events at the expense of dehydration-tolerant grass species, resulting in potentially strong changes in the functioning of these ecosystems
Optical energy harvesting in a smart materials-based micro-actuator using a vertical multi-junction PV cell
No full textInternational audienceThis paper illustrates the energy harvesting principle established in an optical micro-electro-mechanical system (MEMS) using a vertical multi-junction photovoltaic cell (PV cell: 3*3*0.1 mm). The micro-system is a bistable micro-actuator which includes two active shape memory alloy elements (SMA: 3*1*0.1 mm), heated by a laser beam. The SMA elements are used as a biasing spring to activate the micro-system. In this study, the focus is only on actuating the SMA while harvesting energy converted from laser lighting. First, the laser is homogenized using an N-BK7 light pipe homogenizing rod (75*2 mm). Then, the uniformity is verified experimentally using an optoelectronic system able to measure the power on every 800 μm of the surface; resulting an average output power of 100 mW with a variation of ±9%. Next, the current/voltage (IV) curve of the PV cell is extracted, for an irradiance of 1.05 W/cm2, giving a maximum electric power of 32.5 mW. The set-up for the system is modelled using Creo software and executed by resin 3D printing. Finally, the actuation of each SMA element is done alternately (period = 6 sec) using a MEMS active mirror which steers the homogenized laser onto them. While cycling, the unused optical energy from the laser is detected by the PV cell resulting to harvest around 60 mJ per cycle. This energy is stored in a solid state thin film micro-battery. In the future work, the SMA elements will actuate the bistable micro-actuator and the quantity of energy harvested will be extracted
Knowledge, attitudes, harm perception, and practice related to waterpipe smoking in Lebanon
No full textInternational audienceWaterpipe smoking (WPS) is one of the most emerging popular trends in Lebanon, with a prevalence of 36.9%, the highest among all Middle Eastern countries. Thus, the primary objective of the study was to examine the factors associated with knowledge, attitudes, and practice (KAP) related to WPS among a representative sample of waterpipe smokers. The secondary objective was to examine the effect of KAP on cumulative waterpipe dose and dependence. This cross-sectional study was carried out between May and December 2018 and enrolled a representative sample of 1550 waterpipe smokers from all Lebanese districts. The questionnaire used was specifically designed for this study. High knowledge score (Beta = 0.02, p = 0.002) were significantly associated with higher waterpipe harm perception score. In addition, high knowledge score (Beta = 0.32, p = 0.007) were significantly associated with higher attitude score toward smoking ban. Higher waterpipe harm perception score (Beta = - 1.30, p < 0.001), higher attitude (Beta = - 0.21, p < 0.001), and higher knowledge score (Beta = - 0.11, p < 0.001) were significantly associated with lower waterpipe dependence. In addition, higher waterpipe dependence (Beta = 2.02, p < 0.001) was significantly associated with higher cumulative waterpipe smoking, while higher waterpipe harm perception score (Beta = - 1.96, p = 0.009) and higher knowledge score (Beta = 0.27, p < 0.001) were significantly associated with lower cumulative waterpipe smoking. Our main finding was that better knowledge and perception of the harmful effects of waterpipe were related to a better attitude toward smoking bans and a lower waterpipe smoking. Therefore, health care providers and policymakers should join efforts to make awareness campaigns across Lebanon and develop adequate interventions to curb the use of waterpipe among the population
Cross-cultural differences in orthorexic eating behaviors: Associations with personality traits
No full textInternational audienceObjectives: Sociocultural factors and personality traits play key roles in determining dietary behaviors. Orthorexia nervosa (ON), the pathologic obsession with healthy eating, is increasingly receiving scientific attention. However, mechanisms and risk factors are not completely understood. The aims of this study were to compare the prevalence of orthorexic eating attitudes among adults in Germany and Lebanon, and to examine the relationship with primary facets of personality and maladaptive personality traits.Methods: The German sample comprised 391 adults, of which 314 were women (80.3%) and the mean age was 27 y. The Lebanese sample comprised 519 adults, of which 283 were women (56%) and the mean age was 36 y. In addition to sociodemographic data, participants completed the Dusseldorf Orthorexia Scale (DOS), the Teruel Orthorexia Scale (TOS), the Big Five Inventory, and the Personality Inventory for the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition.Results: Generally higher levels of healthy orthorexia among women and higher levels of ON according to the TOS-ON and DOS scores were found in Lebanon. In the Lebanese sample, 8.4% presented a high risk for ON, whereas this was true for only 4.9% of the German sample. Some associations between DOS/TOS scores and personality traits appeared but coefficients were generally low. Hierarchical multiple regression showed that the negative association between ON and the traits agreeableness and negative affectivity was clearly evident in the Lebanese sample but less so in the German sample. Age, body mass index, marital status, and subjective social status were not relevant moderators of effects. Comparison by country indicated higher prevalence of pathologic healthful eating and ON in the Lebanese sample compared with the German group. Personality traits, but not sociodemographic variables, partly contributed to this difference.Conclusion: The present results suggested the importance of sociocultural factors in the development of eating pathologies and proposed specific personality traits as important associated factors
Genetic Diversity among Ancient Rainfed Lebanese Barley (Hordeum vulgare L.) Landrace Baladi by Using Morphological Traits and Microsatellites Markers
No full textInternational audienceLebanese barley landrace Baladi is not sufficiently analyzed morphologically and genetically. This investigation was carried out to evaluate Baladi in its center of diversification by using morphological traits and microsatellite markers (SSR). The genetic diversity of 237 accessions of Lebanese barley landrace Baladi was evaluated by using 19 morphological traits. Principal components analysis showed that plant height, awn color, number of rows, length of rachilla hairs, number of spikelets per spike, number of seeds per spike and shape of lemma tip for sterile spikelets were the most significant traits. Regarding the relationship between plants, dendrogram constructed according to Jaccard distance, clearly separated the studied spikelets into 19 distinguished morphological profiles. A total of 55 genomic DNA extracted from selected accessions were analyzed using seven microsatellite markers (SSRs). A high level of polymorphism information content (PIC; average = 0.66) was observed. The polymorphic primers revealed 16 alleles with an average of 5.3 alleles per polymorphic primer. The highest number of polymorphic bands was developed by the primer pairs MGB402 (7 alleles). In the dendrogram constructed based on the SSR data, the evaluated lines were classified into two major clusters corresponding to the number of rows per spike (two-rows or six-rows). Based on this study, it can be concluded that there is a high level of genetic diversity within Baladi barley landrace in Lebanon. These results will be useful for barley germplasm management in terms of biodiversity protection and as a valuable source of gene pool for new useful alleles for crop improvement
Wildfires front dynamics: 3D structures and intensity at small and large scales
No full textInternational audienceThe 3D structure of a fire front propagating through a homogeneous porous solid-fuel layer was studied numerically at laboratory and field scales. At laboratory scale, wind-tunnel fires propagating through laser-cut cardboard fuel were numerically reproduced, while at field scale, simulations of grassland fires with quasi-infinite fire front were carried out for different wind speeds. These simulations were performed using FIRESTAR3D, based on a multiphase formulation that includes the main physical phenomena governing fire behavior. An unsteady RANS approach and a Large Eddy Simulation (LES) approach were used to simulate the reactive turbulent flow, whereas turbulent combustion was modeled using Eddy Dissipation Concept (EDC). Unlike other 3D wildfire tools available in the community, such as FIRETEC and WFDS, the model is based on an implicit, low-Mach number resolution of the governing equations, and makes no empirical assumptions in the resolution of the radiative transfer equation. The comparison with the experimental data concerned mainly the Rate of Spread (ROS) of fire, the fireline intensity, the flame-zone depth, and the wavelength characterizing the crest-and-trough structure of the fire front along the transverse direction. Particular attention was drawn to the similitude in the fire front dynamics between small and large scales. In order to highlight the physical mechanisms responsible for this dynamics, a dimensional analysis was carried out by introducing Byram's convection number N-C based on the fireline intensity and Froude's numbers Fr based on the characteristic wavelength of the fire-front structure. The analysis shows that all the results (wind-tunnel fires and grassland fires, experimental and numerical) collapsed on a single scaling law in the form Fr = N-C(-)2/3
Les compétences « psychotérapeutiques » du dirigeant à l’aune d’une crise globale
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Turmeric and Its Major Compound Curcumin on Health: Bioactive Effects and Safety Profiles for Food, Pharmaceutical, Biotechnological and Medicinal Applications
No full textInternational audienceCurcumin, a yellow polyphenolic pigment from theCurcuma longaL. (turmeric) rhizome, has been used for centuries for culinary and food coloring purposes, and as an ingredient for various medicinal preparations, widely used in Ayurveda and Chinese medicine. In recent decades, their biological activities have been extensively studied. Thus, this review aims to offer an in-depth discussion of curcumin applications for food and biotechnological industries, and on health promotion and disease prevention, with particular emphasis on its antioxidant, anti-inflammatory, neuroprotective, anticancer, hepatoprotective, and cardioprotective effects. Bioavailability, bioefficacy and safety features, side effects, and quality parameters of curcumin are also addressed. Finally, curcumin's multidimensional applications, food attractiveness optimization, agro-industrial procedures to offset its instability and low bioavailability, health concerns, and upcoming strategies for clinical application are also covered