Plasma Photoinactivation of Bacterial Isolated from Blood Donors Skin: Potential of Security Barrier in Transfusional Therapy.

The presence of skin bacteria capable of forming biofilm, exhibiting antibiotic resistance, and displaying virulence represents a significant challenge in the field of transfusion medicine. This underscores the necessity of enhancing the microbiological safety of blood and blood components against pathogens with virulent characteristics. The aim of this work was to demonstrate bacterial inactivation in plasma by using a photoinactivation method against virulent bacteria and to evaluate coagulation factors before and after treatment. Logarithmic loads of biofilm-producing, antibiotic-resistant, and virulent bacteria isolated from skin (Enterobacter cloacae, Klebsiella ozaenae, and Staphylococcus epidermidis) were used in artificial contamination assays of fresh frozen plasma bags and subjected to photoreduction. FVIII and FI activity were evaluated before and after photoinactivation. The photoinactivation of plasma was demonstrated to be an effective method for the elimination of these bacteria. However, the efficiency of this method was found to be dependent on the bacterial load and the type of test microorganism. Conversely, decay of coagulation factors was observed with net residual activities of 61 and 69% for FVIII and FI, respectively. The photoinactivation system could have a bias in its effectiveness that is dependent on the test pathogen. These findings highlight the importance of employing technologies that increase the safety of the recipient of blood and/or blood components, especially against virulent bacteria, and show the relevance of the role of photoinactivation systems as an option in transfusion practice.

Mooney-Rivlin Parameter Determination Model as a Function of Temperature in Vulcanized Rubber Based on Molecular Dynamics Simulations.

The automotive industry is entering a digital revolution, driven by the need to develop new products in less time that are high-quality and environmentally friendly. A proper manufacturing process influences the performance of the door grommet during its lifetime. In this work, uniaxial tensile tests based on molecular dynamics simulations have been performed on an ethylene-propylene-diene monomer (EPDM) material to investigate the effect of the crosslink density and its variation with temperature. The Mooney-Rivlin (MR) model is used to fit the results of molecular dynamics (MD) simulations in this paper and an exponential-type model is proposed to calculate the parameters C1(T) and C2T. The experimental results, confirmed by hardness tests of the cured part according to ASTM 1415-88, show that the free volume fraction and the crosslink density have a significant effect on the stiffness of the EPDM material in a deformed state. The results of molecular dynamics superposition on the MR model agree reasonably well with the macroscopically observed mechanical behavior and tensile stress of the EPDM at the molecular level. This work allows the accurate characterization of the stress-strain behavior of rubber-like materials subjected to deformation and can provide valuable information for their widespread application in the injection molding industry.

Comparative Study of Machine Learning Models for Bee Colony Acoustic Pattern Classification on Low Computational Resources.

In precision beekeeping, the automatic recognition of colony states to assess the health status of bee colonies with dedicated hardware is an important challenge for researchers, and the use of machine learning (ML) models to predict acoustic patterns has increased attention. In this work, five classification ML algorithms were compared to find a model with the best performance and the lowest computational cost for identifying colony states by analyzing acoustic patterns. Several metrics were computed to evaluate the performance of the models, and the code execution time was measured (in the training and testing process) as a CPU usage measure. Furthermore, a simple and efficient methodology for dataset prepossessing is presented; this allows the possibility to train and test the models in very short times on limited resources hardware, such as the Raspberry Pi computer, moreover, achieving a high classification performance (above 95%) in all the ML models. The aim is to reduce power consumption and improves the battery life on a monitor system for automatic recognition of bee colony states.

Development of bioplastics from a microalgae consortium from wastewater.

Nowadays, as the world population is in need of creating alternative materials that can replace conventional plastics, microalgae biomass may be identified as a viable source for producing more environmentally friendly materials. Scenedesmus sp and Desmodesmus sp are the main components (~80%) of a microalgae consortium (MC) that first has been used to remove Nitrogen and Phosphorus from wastewater. The potential to develop bioplastic materials from MC considering its relatively high protein content (~48%) has been assessed in the present manuscript, using as a reference a commercial biomass rich an Arthrospira specie (AM) also present in the studied consortium. Bioplastics were obtained through injection moulding of blends obtained after mixing with different amounts of glycerol, and eventually characterized using Dynamic Mechanical Thermal Analysis (DMTA), water immersion and tensile tests. All bioplastics displayed a glass transition temperature around 60 °C, showing a thermoplastic behavior which is less pronounced in the CM based bioplastics. This would imply a greater thermal resistance of bioplastics produced from the biomass harvested in wastewater. Moreover, these bioplastics showed a lower ability to absorb water when immersed, due to the lower deformability displayed in the tensile tests. The mechanical properties of all samples, independently of the nature of the biomass, were improved when the presence of the biomass was higher. Therefore, results here presented prove the potential of valorisation of microalgae consortia used in the effective treatment of wastewater through the development of bioplastic materials.

Molecular diagnosis of dengue virus infections in samples collected on filter paper / Diagnóstico molecular de infecciones por virus Dengue en muestras colectadas en papel de filtro

Dengue virus infections (DENV) are a severe public health problem due to the high rates of morbidity and mortality involved, and the fact that no clinical treatment or vaccines are available. In order to strengthen the laboratory diagnosis for surveillance systems in tropical countries with low resources, we report an optimized method using filter paper for blood spotting and subsequent molecular diagnosis of DENV serotypes. Control strains of all serotypes, as well as 35 whole blood patient samples dispensed on filter paper, were stored at room temperature for as long as 36 months. RT-PCR of 5’UTR-C fragment was amplified through adapted protocols to diagnose all dengue serotypes. Results showed amplification for all four viral serotypes, including control viral strains and 88.6 % of the samples. These results allowed determining the utility of filter paper for the preservation of samples regularly obtained from patients with clinical suspicion of dengue in settings where low resources do not permit an immediate analysis of the samples. Likewise, this study evidence the possibility of molecular diagnosis of DENV from multiple areas of the world where there are no laboratories with the capacity to confirm DENV cases.

Las infecciones por virus Dengue (DENV) representan un grave problema de salud pública debido a las altas tasas de morbilidad y mortalidad que causan, además no cuentan con tratamiento clínico específico, ni vacuna. Con el fin de reforzar el diagnóstico de laboratorio para los sistemas de vigilancia epidemiológica en países tropicales con recursos económicos limitados, se optimizó una metodología utilizando papel de filtro para la recolección de muestras y el subsiguiente diagnóstico molecular de los serotipos de DENV. Se emplearon cepas controles correspondientes a todos los serotipos virales, así como 35 muestras de sangre total dispensadas en papel de filtro que fueron mantenidas a temperatura ambiente por 36 meses. Las muestras fueron analizadas mediante RT-PCR para la amplificación de la región del genoma correspondiente a 5´UTR-C de los DENV. Los resultados mostraron la amplificación de los mencionados fragmentos en 88,6% de las muestras analizadas, así como de las cepas controles. Estos resultados evidenciaron la utilidad del papel de filtro para conservación de muestras obtenidas de pacientes con sospecha clínica de dengue ubicados en zonas donde no es posible realizar análisis de laboratorio de forma inmediata, así como su uso para el diagnóstico molecular. De este modo se reforzaría la vigilancia en áreas, donde no hay laboratorios con capacidad para confirmar casos de DENV.

Shear and extensional properties of kefiran.

Kefiran is a neutral polysaccharide constituted by glucose and galactose produced by Lactobacillus kefiranofaciens. It is included into kefir grains and has several health promoting properties. In the present work, shear and extensional properties of different kefiran aqueous dispersions (0.5, 1 and 2% wt.) were assessed and compared to other neutral gums commonly used in food, cosmetic and pharmaceutics industries (methylcellulose, locust bean gum and guar gum). Kefiran showed shear flow characteristics similar to that displayed by other representative neutral gums, although it always yielded lower viscosities at a given concentration. For each gum system it was possible to find a correlation between dynamic and steady shear properties by a master curve including both the apparent and complex viscosities. When studying extensional properties of selected gums at 2% wt. by means of a capillary break-up rheometer, kefiran solutions did not show important extensional properties, displaying a behaviour close the Newtonian.