Search

In the present work it was studied the main aspect that influences on degradation and physical-chemical properties at grainboundary region of metal oxide varistors and its consequences on microstructure and nonohmic electric properties. Based on the comprehension of the degradation aspects it was proposed some methodologies to recover the varistors nonohmic properties after being failed with long (2000 μs) and short current pulses (8/20 μs). Our analysis shown that one of the cause of degradation process is related to the lowering of oxygen species amount at grain-boundary region. Therefore, it is possible to re-promote oxygen enrichment of such regions by specific thermal treatments in rich oxygen atmospheres (the best condition found in the present work was temperatures around 900°C for 2 h at an oxygen flux of 15 l/h). The proposed nonohmic properties recovering procedure appear to be valid for all kind metal oxide varistors studied and is very important from technological point of view.En este trabajo se estudia el fenómeno de la degradación eléctrica en varistores basados en ZnO y los factores físico-químicos que influyen en ella, así como su efecto sobre la microestructura y propiedades eléctricas. Con la comprensión de los fenómenos de degradación se proponen metolodogías para recuperar varistores después de fallados con pulsos de corriente de larga (2000 μs) y corta duración (8/20 μs). Los análisis mostraron que una de las causas de degradación es la pérdida de especies de oxígeno en el borde de grano, permitiendo implementar un tratamiento térmico posterior en atmósfera enriquecida de oxígeno para recuperar las propiedades del varistor (temperatura de 900°C por dos horas y 15 l/h de flujo de oxígeno, fue la mejor condición). El procedimiento de recuperación propuesto es válido para todos los sistemas varistores con base en óxido metálico, sean comerciales o no y es de gran interés tecnológico, pues torna viable el reciclaje de una gran cantidad de piezas cerámicas que actualmente son descartadas sin ningún uso.

Challenge 10 of the United Nations Decade of Ocean Science for Sustainable Development (2021–2030) calls for the restoration of society's relationship with the ocean. Research suggests that the relationship people have with marine environments can influence their depth of engagement in marine citizenship action, and the important role for 'marine identity' in driving that action. Although identity is well‐researched, marine identity is a concept novel to academia and a baseline understanding is required, both to grasp the scope of the concept, and to support research into its role in transforming the human‐ocean relationship.Here, a transdisciplinary study, endorsed as a UN Ocean Decade Activity and by the EU Mission Ocean & Waters, brought together a multinational community of marine researchers and practitioners to co‐produce a baseline conceptualisation of marine identity, drawing on photovoice and deliberative methodology. This paper presents the findings of the co‐production process and offers a first introduction in the literature of the multiple variations and formations of marine identity.We find marine identity to be a complex and multidimensional concept, suffused with individual experiences and understandings of the marine environment, based on social and cultural understandings of the ocean, contemporarily and historically. We present real‐world examples of marine identity to illustrate key themes that were developed through co‐production.Policy implications: We propose marine identity as a catalyst for understanding existing multifaceted and caring relationships with the ocean, as well as the restoration of society's relationship with the ocean. Marine identity research should, therefore, be prioritised in research seeking to contribute to the UN Ocean Decade Challenge 10, as this will support integration of non‐material values of the ocean into marine planning processes and policy making, enabling effective responses to Challenge 10's emphasis on integrating traditional/cultural ways of knowing and valuing the marine environment, through diverse marine identities. We welcome research efforts that will further develop the marine identity concept and empirically investigate the relationships between marine identity, marine citizenship, and people's relationships with the ocean. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

PIWI proteins are stem cell-associated RNA-binding proteins crucial for survival of germ stem cells. In cancer, PIWI proteins are overexpressed. Specifically, PIWIL4 is highly expressed in multiple cancers with the highest levels found in acute myeloid leukemia (AML), an aggressive malignancy propagated by a population of leukemia stem cells (LSCs). Bamezai et al. (Blood Journal, blood, 2023, 142, 90-105) demonstrated that PIWIL4 supports AML blasts and LSCs but is not necessary for healthy human hematopoietic progenitor stem cells (HSPCs) function in vivo. PIWIL4 in AML acts by preventing the accumulation of R-loops in key genes for LSCs persistence implicated in: DNA damage, replicative stress, and transcription arrest. We report that PIWIL4 expression significantly decreases in THP-1 monocytes exposed to a differentiating agent, suggesting a potential role for PIWIL4 in maintaining the undifferentiated state of myeloid cells. PIWIL4 overexpression could lead to the emergence of LSCs, driving leukemia propagation and maintenance. Our findings correlate with the persistent overexpression of PIWIL4 in myeloid cancers as reported by Bamezai et al., and suggest that PIWIL4 may be involved in myeloid cell differentiation. In this perspective, we highlight recent findings on the implication of PIWI pathway in maintaining AML stemness. Additionally, we propose further investigation on the role of PIWI pathway in oncogenesis and cellular differentiation as a strategy to identify biomarkers and therapeutic targets for AML. [ABSTRACT FROM AUTHOR]

Copyright of Estudos em Comunicação is the property of Labcom / Universidade da Beira Interior and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent studies show that the character, function and goals of educational development units (EDUs) in many countries are undergoing a shift, and they now tend to support universities and learning in a more comprehensive way. The status of Spanish EDUs, however, has not been studied in detail. The aim of this article is to describe the current status of 45 such units to explore the degree to which a similar shift can be observed. The data revealed clusters, from which four models were defined. The models illustrate the increasing diversity of functions and widening scope of practice within Spanish EDUs.