Study of the Mechanical and Physical Behavior of Gypsum Boards with Plastic Cable Waste Aggregates and Their Application to Construction Panels.

The objective of this study was to analyze the physico-mechanical properties of gypsum boards including plastic waste aggregates from cable recycling. The plastic cable waste is incorporated into the gypsum matrix without going through any type of selection and/or treatment, as it is obtained after the cable recycling process. In the experimental process, gypsum boards of different dimensions were manufactured and tested for their Young's modulus, shock-impact resistance, flexural strength, thermal conductivity, and thermal comfort. The results obtained show a significant increase in the elasticity of the boards with plastic waste (limited cracking), compliance with the minimum value of flexural strength, and a slight improvement in the thermal conductivity coefficient (lower energy demand) and surface comfort (reduced condensation and greater adherence). Therefore, the analyzed material could provide a suitable alternative to currently marketed gypsum boards, contributing to sustainable construction not only in new constructions, but also in building renovations.

Characterization of a New Lightened Gypsum-Based Material Reinforced with Fibers.

This paper shows the characterization of a new lightened gypsum-based material for use in buildings. A plaster material has been designed with a polymeric compound based on polyvinyl acetate, bicarbonate and a boric acid solution, which reduce the density and thermal conductivity by up to 20% and 30%, respectively. In addition, tests have been carried out with the lightened plaster material reinforced with glass (GF), basalt (BF), polypropylene (PPF) and wood (WF) fibers. A significant improvement in mechanical properties was achieved. All samples obtained resistance values greater than 2 MPa in flexion and 3 MPa in compression. Physico-chemical analysis were also carried out. The study is completed with a statistical analysis, where confidence intervals have been obtained for the mean at 95% confidence for each of the physical properties studied.

Low-Cost Sensors for Determining the Variation in Interior Moisture Content in Gypsum Composite Materials.

Non-destructive testing can be used to determine some of the most relevant physical properties of building materials. In this work, two low-cost measuring devices were developed capable of determining the variation in real-time of the percentage of humidity that is produced in the construction of gypsum and plaster during the hardening process. For this, an Arduino resistive sensor and a capacitive sensor of our design were used. The results show how it is possible to determine the variations in mixing water content during the seven days of curing established by the UNE-EN 13279-2 standard as well relate to the mechanical resistance of the test specimens with the same percentage of humidity. Additionally, the study was completed with the determination of the formation of the dihydrate compound linked to this setting process in the test specimens by conducting X-ray diffraction and thermogravimetric analysis tests at different ages of the samples.

Infectivity and virulence of Trypanosoma evansi and Trypanosoma equiperdum Venezuelan strains from three different host species.

The infectivity and virulence of seven Trypanosoma evansi and Trypanosoma equiperdum Venezuelan strains isolated from horses, donkeys and capybaras were compared in a mouse model up to 41 days, for parasitemia, animal weight, survival rates, packed cell volume, haemoglobin and erythrocyte count. Two T. equiperdum strains and three of the T. evansi strains resulted in 100% mice mortality, while the two T. evansi donkey strains exhibited lower infectivity and mortality. T. equiperdum strains had shorter pre-patent periods (4 days) than the T. evansi strains (4-12 days). In terms of pathogenicity, only the T. evansi horse strain and the two capybara strains produced a significant decrease of the packed cell volume, in haemoglobin concentration and in red blood cell count. In contrast, the T. evansi donkey strains did not show any changes in the hematological parameters. From the seven variables studied, only pre-patent period, day of maximum parasitemia, day of first parasitemia peak and number of parasitemia peaks were statistically significant. Weight decrease was only observed in mice infected with the T. evansi horse strain. T. equiperdum strains showed the highest mice lethality (7% survival by day 8 post-infection) with no change in the hematological parameters. The three T. evansi horse and capybara strains showed 80%, 87% and 97% survival rates, respectively by day 12 post-infection. However, by day 20 post-inoculation all the mice infected with the T. evansi horse strain died, while 53% and 27% capybara strains infected survived. Whereas by day 40 post-infection, 53 and 73% of the mice infected with the T. evansi donkey strains had survived. These results demonstrate striking infectivity and virulence differences between Venezuelan T. evansi and T. equiperdum strains in NMRI mice and open new possibilities to characterize inter and intra-species variations that may contribute to the pathogenicity of these two species.

Apoptotic-like activity of staurosporine in axenic cultures of Trypanosoma evansi.

Trypanosoma evansi is a blood protozoan parasite of the genus Trypanosoma which is responsible for surra (Trypanosomosis) in domestic and wild animals. This study addressed apoptotic-like features in Trypanosoma evansi in vitro. The mechanism of parasite death was investigated using staurosporine as an inducing agent. We evaluated its effects through several cytoplasmic features of apoptosis, including cell shrinkage, phosphatidylserine exposure, maintenance of plasma membrane integrity, and mitochondrial trans-membrane potential. For access to these features we have used the flow cytometry and fluorescence microscopy with cultures in the stationary phase and adjusted to a density of 10(6) cells/mL. The apoptotic effect of staurosporine in T. evansi was evaluated at 20 nM final concentration. There was an increase of phosphatidylserine exposure, whereas mitochondrial potential was decreased. Moreover, no evidence of cell permeability increasing with staurosporine was observed in this study, suggesting the absence of a necrotic process. Additional studies are needed to elucidate the possible pathways associated with this form of cell death in this hemoparasite.

Apoptotic-like activity of staurosporine in axenic cultures of Trypanosoma evansi / Actividad proapoptótica de la estaurosporina en cultivos axénicos de Trypanosoma evansi

Trypanosoma evansi is a blood protozoan parasite of the genus Trypanosoma which is responsible for surra (Trypanosomosis) in domestic and wild animals. This study addressed apoptotic-like features in Trypanosoma evansi in vitro. The mechanism of parasite death was investigated using staurosporine as an inducing agent. We evaluated its effects through several cytoplasmic features of apoptosis, including cell shrinkage, phosphatidylserine exposure, maintenance of plasma membrane integrity, and mitochondrial trans-membrane potential. For access to these features we have used the flow cytometry and fluorescence microscopy with cultures in the stationary phase and adjusted to a density of 10(6) cells/mL. The apoptotic effect of staurosporine in T. evansi was evaluated at 20 nM final concentration. There was an increase of phosphatidylserine exposure, whereas mitochondrial potential was decreased. Moreover, no evidence of cell permeability increasing with staurosporine was observed in this study, suggesting the absence of a necrotic process. Additional studies are needed to elucidate the possible pathways associated with this form of cell death in this hemoparasite.

Trypanosoma evansi es un hemoparásito, el cual es el agente causal de la surra (tripanosomiasis) en mamíferos, perteneciente al orden Kinetoplastidae. Este estudio se oriento a caracterizar la muerte celular similar a apoptosis en cultivos in vitro de Trypanosoma evansi a través del uso del inductor esturosporina. Este efecto se evaluó a través de diversos aspectos fenotípicos de la apoptosis: el encogimiento celular, la exposición de fosfatidilserina, el mantenimiento de la integridad de la membrana plasmática y el potencial de membrana mitocondrial. Para evaluar estas características se utilizaron técnicas de citometría de flujo y microscopía de fluorescencia con cultivos en fase estacionaria ajustados a una densidad de 10(6) células/mL. El efecto apoptótico de la estaurosporina en Trypanosoma evansi fue evaluado a una concentración de 20 nM. Se evidenció un aumento de la exposición a fosfatidilserina, mientras que el potencial mitocondrial disminuyó. Por otra parte, no hay evidencias de aumento de la permeabilidad celular con estaurosporina, sugiriendo la ausencia de un proceso necrótico. Estudios adicionales son necesarios para dilucidar las posibles vías asociadas con esta forma de muerte celular en este hemoparásito.