Microred eléctrica: operación en estado estable

Resumen—La operación y control de las microredes eléctricas, es parte fundamental para mantener la seguridad del sistema, la operación óptima y la reducción de gases contaminantes. Las microredes eléctricas operan interconectadas a la red eléctrica principal, en modo aislado o en modo dual. El documento propone el análisis en estado estable de una microred interconectada a la red principal del Campus Siglo XXI de la Universidad Autónoma de Zacatecas. El análisis muestra los resultados del estado de operación de la microred, como límites de voltaje en los buses de la red, seguridad del sistema y la distribución de los flujos de potencia en líneas de distribución y transformadores

Pathogen and Circadian Controlled 1 (PCC1) regulates polar lipid content, ABA-related responses, and pathogen defence in Arabidopsis thaliana

Pathogen and Circadian Controlled 1 (PCC1) was previously characterized as a regulator of defence against pathogens and stress-activated transition to flowering. Plants expressing an RNA interference construct for the PCC1 gene (iPCC1 plants) showed a pleiotropic phenotype. They were hypersensitive to abscisic acid (ABA) as shown by reduced germination potential and seedling establishment, as well as reduced stomatal aperture and main root length in ABA-supplemented media. In addition, iPCC1 plants displayed alterations in polar lipid contents and their corresponding fatty acids. Importantly, a significant reduction in the content of phosphatidylinositol (PI) was observed in iPCC1 leaves when compared with wild-type plants. A trend in reduced levels of 18:0 and increased levels of 18:2 and particularly 18:3 was also detected in several classes of polar lipids. The enhanced ABA-mediated responses and the reduced content of PI might be responsible for iPCC1 plants displaying a complex pattern of defence against pathogens of different lifestyles. iPCC1 plants were more susceptible to the hemi-biotrophic oomycete pathogen Phytophthora brassicae and more resistant to the necrotrophic fungal pathogen Botrytis cinerea compared with wild-type plant

Lipid Composition and Associated Gene Expression Patterns during Pollen Germination and Pollen Tube Growth in Olive (Olea europaea L.)

Pollen lipids are essential for sexual reproduction but our current knowledge regarding lipid dynamics in growing pollen tubes is still very scarce. Here, we report unique lipid composition and associated gene expression patterns during olive pollen germination. Up to 376 genes involved in the biosynthesis of all lipid classes, except suberin, cutin and lipopolysaccharides, are expressed in the olive pollen. The fatty acid profile of the olive pollen is markedly different compared with other plant organs. Triacylglycerol, containing mostly C12-C16 saturated fatty acids, constitutes the bulk of olive pollen lipids. These compounds are partially mobilized, and the released fatty acids enter the β-oxidation pathway to yield acetyl-CoA, which is converted into sugars through the glyoxylate cycle in the course of pollen germination. Our data suggest that fatty acids are synthesized de novo and incorporated into glycerolipids by the “eukaryotic pathway” in elongating pollen tubes. Phosphatidic acid is synthesized de novo in the endomembrane system during pollen germination and seems to have a central role in the pollen tube lipid metabolism. The coordinated action of fatty acid desaturases FAD2-3 and FAD3B might explain the increase of linoleic and alpha-linolenic acids observed in the germinating pollen. A continuous synthesis of triacylglycerol by the action of DGAT1 enzyme, but not PDAT, seems also plausible. All these data allow for a better understanding of the lipid metabolism during the olive reproduction process, which can impact in the future in the increase of olive fruit yield and, therefore, olive oil production

Production Response and Digestive Enzymatic Activity of the Pacific White Shrimp Litopenaeus vannamei (Boone, 1931) Intensively Pregrown in Microbial Heterotrophic and Autotrophic-Based Systems

Shrimp postlarvae were reared into different microcosm systems without water exchange; a traditional system based on simple fertilization to improve microalgae concentration (control), an autotrophic system (AS) based on the promotion of biofloc and biofilm by the addition of fertilizer and artificial substrates and a heterotrophic system (HS) based on the promotion of heterotrophic bacteria by the addition of nitrogenous and carbonaceous sources and artificial substrates. Better growth performance and survival were registered in shrimp from the AS and HS compared to the control. Feed conversion ratios were below 0.7 for all treatments, but AS and HS were significantly lower than the control. Regarding digestive performance, no significant differences were observed for trypsin, amylase and lipase activities among AS and control shrimp; however, shrimp from HS showed a higher trypsin and amylase activities, suggesting a higher digestive activity caused by the presence of microbial bioflocs. The presence of biofilm and bioflocs composed by either autotrophic or heterotrophic organisms in combination with formulated feed improved the growth performance and survival of shrimp. Apparently, such combination fits the nutritional requirements of shrimp

Evaluación del proceso de distribución de productos de consumo masivo en DIINSA en el municipio de Managua de acuerdo a la Norma ISO 9001-2008.

Presenta una evaluación del proceso de distribución de productos de consumo masivo en DIINSA en el municipio de Managua de acuerdo a la Norma ISO 9001-2008. El objetivo de este trabajo es desarrollar un plan de mejora que le sirva de herramienta de apoyo en su proceso de distribución en la toma de decisiones con el fin de controlar, organizar manejar los recursos humanos y económicos –financieros eficientes

Carbon-Coated Superparamagnetic Nanoflowers for Biosensors Based on Lateral Flow Immunoassays

Superparamagnetic iron oxide nanoflowers coated by a black carbon layer (Fe3O4@C) were studied as labels in lateral flow immunoassays. They were synthesized by a one-pot solvothermal route, and they were characterized (size, morphology, chemical composition, and magnetic properties). They consist of several superparamagnetic cores embedded in a carbon coating holding carboxylic groups adequate for bioconjugation. Their multi-core structure is especially efficient for magnetic separation while keeping suitable magnetic properties and appropriate size for immunoassay reporters. Their functionality was tested with a model system based on the biotin–neutravidin interaction. For this, the nanoparticles were conjugated to neutravidin using the carbodiimide chemistry, and the lateral flow immunoassay was carried out with a biotin test line. Quantification was achieved with both an inductive magnetic sensor and a reflectance reader. In order to further investigate the quantifying capacity of the Fe3O4@C nanoflowers, the magnetic lateral flow immunoassay was tested as a detection system for extracellular vesicles (EVs), a novel source of biomarkers with interest for liquid biopsy. A clear correlation between the extracellular vesicle concentration and the signal proved the potential of the nanoflowers as quantifying labels. The limit of detection in a rapid test for EVs was lower than the values reported before for other magnetic nanoparticle labels in the working range 0–3 × 107 EVs/μL. The method showed a reproducibility (RSD) of 3% (n = 3). The lateral flow immunoassay (LFIA) rapid test developed in this work yielded to satisfactory results for EVs quantification by using a precipitation kit and also directly in plasma samples. Besides, these Fe3O4@C nanoparticles are easy to concentrate by means of a magnet, and this feature makes them promising candidates to further reduce the limit of detectionThis work was supported in part by Spanish Ministry of Economy and Competitiveness under projects MAT2017-84959-C2-1-R and the Principality of Asturias (Spain) under project IDI/2018/000185 and the Consellería de Educación Program for Development of a Strategic Grouping in Materials (AEMAT) at the University of Santiago de Compostela under Grant No. ED431E208/08, Xunta de Galicia. Amanda Moyano was supported by a “Severo Ochoa” fellowship (Consejería de Educación y Cultura del Gobierno del Principado de Asturias, grant BP17-152)S

Medicated Scaffolds Prepared with Hydroxyapatite/Streptomycin Nanoparticles Encapsulated into Polylactide Microfibers

The preparation, characterization, and controlled release of hydroxyapatite (HAp) nanopar-ticles loaded with streptomycin (STR) was studied. These nanoparticles are highly appropriate for the treatment of bacterial infections and are also promising for the treatment of cancer cells. The analyses involved scanning electron microscopy, dynamic light scattering (DLS) and Z-potential measurements, as well as infrared spectroscopy and X-ray diffraction. Both amorphous (ACP) and crystalline (cHAp) hydroxyapatite nanoparticles were considered since they differ in their release behavior (faster and slower for amorphous and crystalline particles, respectively). The encapsulated nanoparticles were finally incorporated into biodegradable and biocompatible polylactide (PLA) scaf-folds. The STR load was carried out following different pathways during the synthesis/precipitation of the nanoparticles (i.e., nucleation steps) and also by simple adsorption once the nanoparticles were formed. The loaded nanoparticles were biocompatible according to the study of the cytotoxicity of extracts using different cell lines. FTIR microspectroscopy was also employed to evaluate the cytotoxic effect on cancer cell lines of nanoparticles internalized by endocytosis. The results were promising when amorphous nanoparticles were employed. The nanoparticles loaded with STR increased their size and changed their superficial negative charge to positive. The nanoparticles’ crystallinity decreased, with the consequence that their crystal sizes reduced, when STR was incorporated into their structure. STR maintained its antibacterial activity, although it was reduced during the adsorption into the nanoparticles formed. The STR release was faster from the amorphous ACP nanoparticles and slower from the crystalline cHAp nanoparticles. However, in both cases, the STR release was slower when incorporated in calcium and phosphate during the synthesis. The biocompatibility of these nanoparticles was assayed by two approximations. When extracts from the nanoparticles were evaluated in cultures of cell lines, no cytotoxic damage was observed at concen-trations of less than 10 mg/mL. This demonstrated their biocompatibility. Another experiment using FTIR microspectroscopy evaluated the cytotoxic effect of nanoparticles internalized by endocytosis in cancer cells. The results demonstrated slight damage to the biomacromolecules when the cells were treated with ACP nanoparticles. Both ACP and cHAp nanoparticles were efficiently encapsulated in PLA electrospun matrices, providing functionality and bioactive properties. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

MALDI-TOF Mass Spectrometry Is a Fast and Reliable Platform for Identification and Ecological Studies of Species from Family Rhizobiaceae

Family Rhizobiaceae includes fast growing bacteria currently arranged into three genera, Rhizobium, Ensifer and Shinella, that contain pathogenic, symbiotic and saprophytic species. The identification of these species is not possible on the basis of physiological or biochemical traits and should be based on sequencing of several genes. Therefore alternative methods are necessary for rapid and reliable identification of members from family Rhizobiaceae. In this work we evaluated the suitability of Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for this purpose. Firstly, we evaluated the capability of this methodology to differentiate among species of family Rhizobiaceae including those closely related and then we extended the database of MALDI Biotyper 2.0 including the type strains of 56 species from genera Rhizobium, Ensifer and Shinella. Secondly, we evaluated the identification potential of this methodology by using several strains isolated from different sources previously identified on the basis of their rrs, recA and atpD gene sequences. The 100% of these strains were correctly identified showing that MALDI-TOF MS is an excellent tool for identification of fast growing rhizobia applicable to large populations of isolates in ecological and taxonomic studies