141 research outputs found

    On the Optimization of the Species Separation in an Inclined Darcy-Brinkman Porous Cavity under the Effect of an External Magnetic Field

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    An investigation is conducted to study analytically and numerically the effect of a magnetic field on the species separation induced by the combined effects of convection and Soret phenomenon in an inclined porous cavity saturated by an electrically conductive binary mixture and provided with four impermeable walls. The long sides of the cavity are subject to uniform heat flux while its short ends are adiabatic. Uniform magnetic field is applied perpendicularly to the heated walls. The mixture satisfies the Boussinesq approximation and the porous medium, modeled according to Darcy-Brinkman’s law, is assumed homogeneous and isotropic .The relevant parameters for the problem are the thermal Rayleigh number (RT = 1 to 106), the Lewis number (Le = 10), the inclination angle of the cavity (θ = 0º to 180), the separation parameter (φ = 0.5), the Darcy number (Da = 10-5 to 103), the Hartmann number (Ha = 0 to 100) and the aspect ratio of the cavity (Ar = 12). The limiting cases (Darcy and pure fluid media) are recovered in this study. Optimum conditions leading to maximum separation of species are determined while varying the governing parameters in their respective ranges. Results show that the magnetic field can enhance the species separation in cases where the optimal coupling between thermosolutal diffusion and convection is not achieved in its absence. On the other hand, in cases where this optimal coupling is reached in the absence of the magnetic field, the application of the latter destroys the separation of species

    MoS2 nanoparticle formation in a low pressure environment

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    Formation of MoS2 nanoparticles at pressures between 0.5 and 10 Torr has been studied. Two different chemistries for the particle nucleation are compared: one based on MoCl5 and H2S, and the other based on MoCl5 and S. In both cases particle formation has been studied in a thermal oven and in a radio-frequency discharge. Typically, the reaction rates at low pressures are too low for an efficient thermal particle production. At pressures below 10 Torr no particle production in the oven is achieved in H2S chemistry. In the more reactive chemistry based on sulfur, the optimal conditions for thermal particle growth are found at 10 Torr and low gas flows, using excess of hydrogen. In the radio-frequency discharge, nanoparticles are readily formed in both chemistries at 0.5 Torr and can be detected in situ by laser light scattering. In the H2S chemistry particles smaller than 100 nm diameter have been synthesized, the sulfur chemistry yields somewhat larger grains. Both in thermal and plasma-enhanced particle syntheses, using excess of hydrogen is beneficial for the stability and purity of the particles

    Fermentación controlada de aceitunas verdes picholine marroquíes sometidas a choque térmico e inoculadas sin sal

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    The present work reports the controlled fermentation of heat-shocked, unsalted and inoculated green olives. The effects of heat-shock (60, 70 and 80 °C three times for 5 min), inoculation with the oleuropeinolytic strain of L. plantarum FSO175 (L.p-FSO175) and the addition of Cell-Free Supernatant of C. pelliculosa L18 (CFS of C.p-L18) on the fermentation process of unsalted green olives were examined. The results showed a drastic reduction in the initial indigenous Enterobacteria, and an improvement in the acidification of heat-shocked olives at 70 and 80 °C, when compared to 60 °C. The inoculation with L.p-FSO175 and addition of CFS of C.p-L18 enhanced the fermentation and preservation of unsalted green olives, indicated by a significant decrease in pH, increase in free acidity and total disappearance of Enterobacteria. The heat-shock treatment at high temperature (80 °C), inoculation with L.p-FSO175 and addition of CFS of C.p-L18 led to the best reduction in bitterness, and favorable color changes (L, a, and b) in fermented olives. This sequential method led to more appreciated sensory characteristics (mainly bitterness and color) of fermented olives, lower spoilage incidence in olives, and reduced fermentation time to 50 days, and therefore may be suitable to control the fermentation of unsalted green olives of the Moroccan picholine variety.El presente trabajo reporta la fermentación controlada de aceitunas verdes sometidas a choque térmico, sin salar e inoculadas. Se estudian los efectos del choque térmico (60 °C, 70 °C y 80 °C tres veces durante 5 min), la inoculación con cepa oleuropeinolítica de L. plantarum FSO175 (L.p-FSO175) y la adición de sobrenadante libre de células de C. pelliculosa L18 (CFS de C.p-L18), sobre el proceso de fermentación de aceitunas verdes sin salar. Los resultados mostraron la drástica reducción de las enterobacterias autóctonas iniciales, y la mejora de la acidificación de las aceitunas sometidas a choque térmico de 70 °C y 80 °C, en comparación con 60 °C. La inoculación con L.p-FSO175 y la adición de CFS de C.p-L18 mejoró la fermentación y conservación de las aceitunas verdes sin salar, indicada por una disminución significativa del pH, aumento de la acidez libre y desaparición total de enterobacterias. El choque térmico a alta temperatura (80 °C), la inoculación con L.p-FSO175 y la adición de CFS de C.p-L18 condujeron a una mejor reducción del amargor y cambios de color favorables (L, a y b) en aceitunas fermentadas. Este método secuencial, que permitió apreciar las características sensoriales (principalmente amargor y color) de las aceitunas fermentadas, y una menor incidencia de deterioro en las aceitunas, y redujo el tiempo de fermentación a 50 días, puede ser adecuado para controlar la fermentación de aceitunas verdes sin salar de Marruecos, variedad picholine

    Biodiversity Studies for Sustainable Lagoon: Thermophilic and Tropical Fish Species vs. Endemic Commercial Species at Mellah Lagoon (Mediterranean, Algeria)

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    Lagoons play an important socio-economic role and represent a precious natural heritage at risk from fishing pressure and chemical and biological pollution. Our research focused on better understanding the discrimination of fish biodiversity, the detection of non-indigenous species, and the valorization of commercial indigenous species at Mellah lagoon (Algeria). Taxonomic characterization and barcoding for all fish species and Inkscape schematic drawings for the most common species are provided. A total of 20 families and 37 species were recorded. The thermophilic species Coris julis, Thalassoma pavo, and Aphanius fasciatus and tropical species such as Gambusia holbrooki and Parablennius pilicornis were identified. Numerous Mediterranean species of socio-economic importance are highlighted, and detailed information is summarized for the lagoon’s sustainability. This short-term evaluation goes hand in hand with long-term programs documenting the interaction between indigenous and non-indigenous species in the lagoon and will allow the development of a provisional relationship model for future studies. Thermophilic and tropical species patterns in the Mellah lagoon are presented. Taken together, we provide useful data that can guide future investigations and may become a potential management tool for achieving the Sustainable Development Goals and protecting species with large socio-economic roles from potential thermal stress impact

    Cardiac contractile dysfunction in insulin-resistant rats fed a high-fat diet is associated with elevated CD36-mediated fatty acid uptake and esterification

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    Changes in cardiac substrate utilisation leading to altered energy metabolism may underlie the development of diabetic cardiomyopathy. We studied cardiomyocyte substrate uptake and utilisation and the role of the fatty acid translocase CD36 in relation to in vivo cardiac function in rats fed a high-fat diet (HFD).Rats were exposed to an HFD or a low-fat diet (LFD). In vivo cardiac function was monitored by echocardiography. Substrate uptake and utilisation were determined in isolated cardiomyocytes.Feeding an HFD for 8 weeks induced left ventricular dilation in the systolic phase and decreased fractional shortening and the ejection fraction. Insulin-stimulated glucose uptake and proline-rich Akt substrate 40 phosphorylation were 41% (p <0.001) and 45% (p <0.05) lower, respectively, in cardiomyocytes from rats on the HFD. However, long-chain fatty acid (LCFA) uptake was 1.4-fold increased (p <0.001) and LCFA esterification into triacylglycerols and phospholipids was increased 1.4- and 1.5-fold, respectively (both p <0.05), in cardiomyocytes from HFD compared with LFD hearts. In the presence of the CD36 inhibitor sulfo-N-succinimidyloleate, LCFA uptake and esterification were similar in LFD and HFD cardiomyocytes. In HFD hearts CD36 was relocated to the sarcolemma, and basal phosphorylation of a mediator of CD36-trafficking, i.e. protein kinase B (PKB/Akt), was increased.Feeding rats an HFD induced cardiac contractile dysfunction, which was accompanied by the relocation of CD36 to the sarcolemma, and elevated basal levels of phosphorylated PKB/Akt. The permanent presence of CD36 at the sarcolemma resulted in enhanced rates of LCFA uptake and myocardial triacylglycerol accumulation, and may contribute to the development of insulin resistance and diabetic cardiomyopathy

    Applications of lignin in the agri-food industry

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    Of late, valorization of agri-food industrial by-products and their sustainable utilization is gaining much contemplation world-over. Globally, 'Zero Waste Concept' is promoted with main emphasis laid towards generation of minimal wastes and maximal utilization of plantbased agri-food raw materials. One of the wastes/by-products in the agri-food industry are the lignin, which occurs as lignocellulosic biomass. This biomass is deliberated to be an environmental pollutant as they offer resistance to natural biodegradation. Safe disposal of this biomass is often considered a major challenge, especially in low-income countries. Hence, the application of modern technologies to effectively reduce these types of wastes and maximize their potential use/applications is vital in the present day scenario. Nevertheless, in some of the high-income countries, attempts have been made to efficiently utilize lignin as a source of fuel, as a raw material in the paper industry, as a filler material in biopolymer based packaging and for producing bioethanol. However, as of today, agri-food industrial applications remains significantly underexplored. Chemically, lignin is heterogeneous, bio-polymeric, polyphenolic compound, which is present naturally in plants, providing mechanical strength and rigidity. Reports are available wherein purified lignin is established to possess therapeutic values; and are rich in antioxidant, anti-microbial, anti-carcinogenic, antidiabetic properties, etc. This chapter is divided into four sub-categories focusing on various technological aspects related to isolation and characterization of lignin; established uses of lignin; proved bioactivities and therapeutic potentials of lignin, and finally on identifying the existing research gaps followed by future recommendations for potential use from agri-food industrial wastes.Theme of this chapter is based on our ongoing project- Valortech, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 810630

    General Anesthetics Inhibit Erythropoietin Induction under Hypoxic Conditions in the Mouse Brain

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    Background: Erythropoietin (EPO), originally identified as a hematopoietic growth factor produced in the kidney and fetal liver, is also endogenously expressed in the central nervous system (CNS). EPO in the CNS, mainly produced in astrocytes, is induced under hypoxic conditions in a hypoxia-inducible factor (HIF)-dependent manner and plays a dominant role in neuroprotection and neurogenesis. We investigated the effect of general anesthetics on EPO expression in the mouse brain and primary cultured astrocytes. Methodology/Principal Findings: BALB/c mice were exposed to 10 % oxygen with isoflurane at various concentrations (0.10–1.0%). Expression of EPO mRNA in the brain was studied, and the effects of sevoflurane, halothane, nitrous oxide, pentobarbital, ketamine, and propofol were investigated. In addition, expression of HIF-2a protein was studied by immunoblotting. Hypoxia-induced EPO mRNA expression in the brain was significantly suppressed by isoflurane in a concentration-dependent manner. A similar effect was confirmed for all other general anesthetics. Hypoxia-inducible expression of HIF-2a protein was also significantly suppressed with isoflurane. In the experiments using primary cultured astrocytes, isoflurane, pentobarbital, and ketamine suppressed hypoxia-inducible expression of HIF-2a protein and EPO mRNA. Conclusions/Significance: Taken together, our results indicate that general anesthetics suppress activation of HIF-2 an

    Characterization of LINE-1 Ribonucleoprotein Particles

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    The average human genome contains a small cohort of active L1 retrotransposons that encode two proteins (ORF1p and ORF2p) required for their mobility (i.e., retrotransposition). Prior studies demonstrated that human ORF1p, L1 RNA, and an ORF2p-encoded reverse transcriptase activity are present in ribonucleoprotein (RNP) complexes. However, the inability to physically detect ORF2p from engineered human L1 constructs has remained a technical challenge in the field. Here, we have employed an epitope/RNA tagging strategy with engineered human L1 retrotransposons to identify ORF1p, ORF2p, and L1 RNA in a RNP complex. We next used this system to assess how mutations in ORF1p and/or ORF2p impact RNP formation. Importantly, we demonstrate that mutations in the coiled-coil domain and RNA recognition motif of ORF1p, as well as the cysteine-rich domain of ORF2p, reduce the levels of ORF1p and/or ORF2p in L1 RNPs. Finally, we used this tagging strategy to localize the L1–encoded proteins and L1 RNA to cytoplasmic foci that often were associated with stress granules. Thus, we conclude that a precise interplay among ORF1p, ORF2p, and L1 RNA is critical for L1 RNP assembly, function, and L1 retrotransposition

    Roles for retrotransposon insertions in human disease

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