New Trends in the Control of Grid-Connected Photovoltaic Systems for the Provision of Ancillary Services

Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).The gradual displacement of conventional generation from the energy mix to give way to renewable energy sources represents a paradigm shift in the operation of future power systems: on the one hand, renewable technologies are, in general, volatile and difficult to predict; and on the other hand, they are usually connected to the grid through electronic power converters. This decoupling due to power converters means that renewable generators lack the natural response that conventional generation has to the imbalances between demand and generation that occur during the regular operation of power systems. Renewable generators must, therefore, provide a series of complementary services for the correct operation of power systems in addition to producing the necessary amount of energy. This paper presents an overview of existing methods in the literature that allow photovoltaic generators to participate in the provision of ancillary services, focusing on solutions based on power curtailment by modifying the traditional maximum power point tracking algorithm

Air pollution and heart failure: relationship with the ejection fraction

To study whether the concentrations of particulate matter in ambient air are associated with hospital admission due to heart failure in patients with heart failure with preserved ejection fraction and reduced ejection fraction

Antifungal Nanocomposites Inspired by Titanate Nanotubes for Complete Inactivation of Botrytis cinerea Isolated from Tomato Infection

"Antifungal silver nanocomposites inspired by titanate nanotubes (AgTNTs) were successfully evaluated for the effective inactivation of the phytopathogenic fungus Botrytis cinerea within 20 min. One-dimensional H2Ti3O7 nanotubes functionalized with silver nanoparticles (AgNPs) exhibit unique surface and antifungal properties for the photoinactivation of B. cinerea. Nanostructured titanates were synthesized by the eco-friendly, practical, microwave-induced, hydrothermal method followed by a highly monodispersive AgNP UV-photodeposition. Protonated nanotubes of ∼11 nm in diameter and four-layers displayed high surface areas, 300 m2/g, with a size functionalization of 5 nm for the AgNPs. UV–vis DRS and XPS allowed the characterization and/or quantification of surface reactive species and cytotoxic silver species such as Ag°, Ag+. The effective biocidal properties of the nanocomposites were confirmed by using the well-known Gram-negative bacteria Escherichia coli, and then proceeding to the effective inactivation of the phytopathogenic fungus under visible light. The photoassisted inactivation mechanism was examined by HAADF-STEM, HRTEM, and FESEM electronic microscopies. A plasmalemma invagination due to oxidative stress caused by reactive oxygen, silver cytotoxicity species, and AgTNT sharp morphology damage expands the conidia to induce the cell death. The impact of the eco-friendly inactivation is significant because of the ease with which it is carried out and the possibility of being performed in situ with plants like tomato and grapes, which are ranked among the most valuable agricultural products worldwide.

Synthesis and Characterisation of Acrylic Resin-Al Powder Composites Suitable for Additive Manufacturing

Stereolithography is an additive manufacturing technology commonly used to build either prototypes or final parts. Nevertheless, the manufacture of structural parts has been ruled out owing to the poor mechanical properties of conventional UV-curable resins. Moreover, the inventory of available commercial resins is still limited and they exhibit low thermal and electrical conductivity values. In this work, some composite materials were designed using Al microparticles dispersed within an SLA commercial resin matrix. These composites overcame the difficulties caused by the light scattering effect during the photopolymerisation process in the SLA technology. Dispersion of the filler was characterised by means of SEM/EDX and AFM. The composites exhibited improved thermal and mechanical behaviour in comparison with the pristine resin. The simplicity of the synthesis method used to prepare the composites provides a convenient starting point to explore new ways of designing composites for SLA with improved mechanical and functional properties

Características psicosociales en niños en contextos de riesgo y de no riesgo

Some researchers have put in evidence the importance of the family for the individual optimal development, as well as the effects due to the lack of this. Reason why it was investigated if there are some differences between children who live in family and children who live in orphaned situation, in psychological variables such as: self-esteem, locus of control, intra-family relationships, confrontation to the problems in life, and functions of the I (self). It worked with a sample composed by 355 children of both sexes that live in family (200) and (155) who live in orphaned situation. All the children are between 9 to14 years old, and live in Toluca, Mexico State City. The results indicate differences in each one of the scales applied in favor of the family children.Diversas investigaciones han puesto en evidencia la importancia de la familia para el desarrollo óptimo del individuo, así como los efectos debido a su ausencia. Por ello, se investigó si existían diferencias en niños que viven en familia y niños huérfanos, en variables psicológicas tales como: Autoestima, Locus de control, Enfrentamiento a los problemas de la vida, Funciones del Yo y Relaciones intrafamiliares, para lo cual se trabajó con una muestra compuesta por 355 niños de ambos sexos que viven en familia (200) y en situación de orfandad (155) entre 9 y 14 años de edad de la ciudad de Toluca, México. Los resultados indican diferencias en cada una de las escalas aplicadas a favor de los niños de familia.   &nbsp

Adenoflemón cervical en la tercera edad. Presentación de un caso / Cervical adenophlegmon in old age. A case report

Se presenta el caso de una paciente de 70 años de edad, raza negra, del sexo femenino, con antecedentes de padecer de diabetes mellitus e hipertensión arterial. Se valoró en la consulta externa del Policlínico Universitario Ernesto Guevara de la Serna de Sandino, de Pinar del Río. Fue evaluado en conjunto por un grupo de especialistas, al presentar un cuadro caracterizado por el aumento de volumen superficial de la región lateral izquierda del cuello, por debajo de la rama horizontal de la mandíbula, a nivel del músculo esternocleidomastoideo, cerca y debajo del pabellón auricular y la parótida, de aproximadamente 5 cm. de diámetro, móvil, doloroso, de superficie lisa y consistencia renitente, sin cambios en la coloración de la piel. Al examen físico otorrinolaringológico no se encontraron otras alteraciones. Se le hizo un ultrasonido en la región afectada y valoró en conjunto el caso efectuado el tratamiento médico, al establecerse el diagnóstico clínico e imaginológico de adenoflemón cervical. Se procedió además a la realización de una BAAF. Los autores presentan las experiencias derivadas de la atención del caso, no frecuente a esta edad y revisan la literatura médica sobre el tema, con especial referencia al diagnóstico y tratamiento.Palabras clave: VÉRTEBRAS CERVICALES/patología, ANCIANO.ABSTRACTA 70 year-old, black race, female patient, suffering from diabetes mellitus and hypertension attended to the consultation. The case was analyzed at "Ernesto Guevara de la Serna" outpatient clinic in Sandino, Pinar del Rio. A group of specialists assessed the case that presented a chart characterized by an increase of superficial volume in left lateral region of the neck, below the horizontal branch of the mandible to the level of sternocleidomastoid muscle, near and below outer ear and the parotid, around 5cm of diameter, movable, painful of smooth surface and renitent consistency, without changes in skin color. No other alterations were found at physical examination or ENT specialist examination while imaging studies in the affected region were as well conducted, the case was assessed considering all these procedures to order medical treatment, clinical and imaging diagnosis established a cervical adenophlegmon. A fine needle aspiration biopsy was also performed. The authors presented the experience derived from the medical care of the case, which is not frequent in this age and reviewed the medical literature about the topic, with special emphasis on diagnosis and treatment.Key words: CERVICAL VERTEBRAE/pathology, AGED

Exploring the origin and fate of surface and sub-surface marine microplastics in the Canary Islands region

The presence of different types of microplastics (MPs) in the Atlantic Ocean has been well-documented, with data collected from the Canary Islands indicating high concentrations of MPs at four different beaches (hot spots). However, critical gaps persist regarding the abundance of MPs in diverse open ocean regions, at varying depths, and their transport behavior and origin. This study aims to evaluate, for the first time, the large-scale (>100 km) and mesoscale (10-100 km) ocean dynamic processes and the resulting transport of MPs in the region. On the one hand, this study investigates the surface velocity of currents between 27-32°N latitude range, establishing correlation with the accumulation of MPs on diverse beaches across several islands of the archipelago. This analysis goes beyond studying the predominant current by integrating data at a smaller geographical scale over a two-year period. Concurrently, previous and ongoing research suggests the presence of small MPs (SMPs,<1 mm) at high concentration at a depth of 1100 meters in this region. By integrating these vertical profiles of MPs with a deep understanding of the physical processes of the Canary region accumulated over decades of research, our study introduces an innovative model that outlines how SMPs are sink and transported in open oceans by water mases. This comprehensive approach not only enhances our understanding of the complex dynamics influencing the distribution of MPs but also provides crucial insights to address the widespread problem of MP pollution in the Atlantic

Cost-effectiveness analysis for joint pain treatment in patients with osteoarthritis treated at the Instituto Mexicano del Seguro Social (IMSS): Comparison of nonsteroidal anti-inflammatory drugs (NSAIDs) vs. cyclooxygenase-2 selective inhibitors

<p>Abstract</p> <p>Background</p> <p>Osteoarthritis (OA) is one of the main causes of disability worldwide, especially in persons >55 years of age. Currently, controversy remains about the best therapeutic alternative for this disease when evaluated from a cost-effectiveness viewpoint. For Social Security Institutions in developing countries, it is very important to assess what drugs may decrease the subsequent use of medical care resources, considering their adverse events that are known to have a significant increase in medical care costs of patients with OA. Three treatment alternatives were compared: celecoxib (200 mg twice daily), non-selective NSAIDs (naproxen, 500 mg twice daily; diclofenac, 100 mg twice daily; and piroxicam, 20 mg/day) and acetaminophen, 1000 mg twice daily. The aim of this study was to identify the most cost-effective first-choice pharmacological treatment for the control of joint pain secondary to OA in patients treated at the Instituto Mexicano del Seguro Social (IMSS).</p> <p>Methods</p> <p>A cost-effectiveness assessment was carried out. A systematic review of the literature was performed to obtain transition probabilities. In order to evaluate analysis robustness, one-way and probabilistic sensitivity analyses were conducted. Estimations were done for a 6-month period.</p> <p>Results</p> <p>Treatment demonstrating the best cost-effectiveness results [lowest cost-effectiveness ratio $17.5 pesos/patient ($1.75 USD)] was celecoxib. According to the one-way sensitivity analysis, celecoxib would need to markedly decrease its effectiveness in order for it to not be the optimal treatment option. In the probabilistic analysis, both in the construction of the acceptability curves and in the estimation of net economic benefits, the most cost-effective option was celecoxib.</p> <p>Conclusion</p> <p>From a Mexican institutional perspective and probably in other Social Security Institutions in similar developing countries, the most cost-effective option for treatment of knee and/or hip OA would be celecoxib.</p

Rescue of neurogenesis and age-associated cognitive decline in SAMP8 mouse: Role of transforming growth factor-alpha

Neuropathological aging is associated with memory impairment and cognitive decline, affecting several brain areas including the neurogenic niche of the dentate gyrus of the hippocampus (DG). In the healthy brain, homeostatic mechanisms regulate neurogenesis within the DG to facilitate the continuous generation of neurons from neural stem cells (NSC). Nevertheless, aging reduces the number of activated neural stem cells and diminishes the number of newly generated neurons. Strategies that promote neurogenesis in the DG may improve cognitive performance in the elderly resulting in the development of treatments to prevent the progression of neurological disorders in the aged population. Our work is aimed at discovering targeting molecules to be used in the design of pharmacological agents that prevent the neurological effects of brain aging. We study the effect of age on hippocampal neurogenesis using the SAMP8 mouse as a model of neuropathological aging. We show that in 6-month-old SAMP8 mice, episodic and spatial memory are impaired; concomitantly, the generation of neuroblasts and neurons is reduced and the generation of astrocytes is increased in this model. The novelty of our work resides in the fact that treatment of SAMP8 mice with a transforming growth factor-alpha (TGFα) targeting molecule prevents the observed defects, positively regulating neurogenesis and improving cognitive performance. This compound facilitates the release of TGFα in vitro and in vivo and activates signaling pathways initiated by this growth factor. We conclude that compounds of this kind that stimulate neurogenesis may be useful to counteract the neurological effects of pathological aging.19 página