4,746 research outputs found
High levels of Fis1, a pro-fission mitochondrial protein, trigger autophagy.
No full textAbstractDamaged mitochondria can be eliminated in a process of organelle autophagy, termed mitophagy. In most cells, the organization of mitochondria in a network could interfere with the selective elimination of damaged ones. In principle, fission of this network should precede mitophagy; but it is unclear whether it is per se a trigger of autophagy. The pro-fission mitochondrial protein Fis1 induced mitochondrial fragmentation and enhanced the formation of autophagosomes which could enclose mitochondria. These changes correlated with mitochondrial dysfunction rather than with fragmentation, as substantiated by Fis1 mutants with different effects on organelle shape and function. In conclusion, fission associated with mitochondrial dysfunction stimulates an increase in autophagy
Mitochondrial morphology in mitophagy and macroautophagy.
No full textAbstractMitochondria are critical organelles in energy conversion, metabolism and amplification of signalling. They are however also major sources of reactive oxygen species and when dysfunctional they consume cytosolic ATP. Maintenance of a cohort of healthy mitochondria is therefore crucial for the overall cell fitness. Superfluous or damaged organelles are mainly degraded by mitophagy, a selective process of autophagy. In response to the triggers of mitophagy, mitochondria fragment: this morphological change accompanies the exposure of “eat-me” signals, resulting in the engulfment of the organelle by the autophagosomes. Conversely, during macroautophagy mitochondria fuse to be spared from degradation and to sustain ATP production in times of limited nutrient availability. Thus, mitochondrial shape defines different types of autophagy, highlighting the interplay between morphology of the organelle and complex cellular responses. This article is part of a Special Issue entitled: Mitochondrial dynamics and physiology
Mitochondrial elongation during autophagy: a stereotypical response to survive in difficult times.
No full textLC compensators for power factor correction of nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEA method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples
LC compensators based on transmission loss minimization for nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThis paper presents a method employing the penalty function search algorithm to determine the LC compensator value for the optimal power factor correction in nonsinusoidal systems. The objective of the proposed method is to minimize the transmission loss while the power factor and efficiency are taken as constraints and utilized in order to solve the multiobjective optimization problem by transforming it into a single objective one. Examples show that the load nonlinearity can have a significant impact on optimal compensator sizes
During autophagy mitochondria elongate, are spared from degradation and sustain cell viability.
No full textEssential amino acids and glutamine regulate induction of mitochondrial elongation during autophagy.
No full textUofG welcomes Palestinian students
No full textNews article on the arrival of the largest cohort of Gaza/Palestinian Exchange students in the UK to date. Partnership project supported by a €585,150.00 Erasmus+ International Credit Mobility fund. Partnership developed by Dr Luis Gomes (College of Arts Mobility Officer, 2012-2017), and Mr Bill Guariento (SMLC/EAP Lecturer). It builds on the previous telecollaboration project by Bill Guariento and Anna Rolinska (SMLC/EAP), the EAST Project (https://easttelecollaboration.wordpress.com/project-team/)
Cost-effective applications of power factor correction for nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2005 IEEEThe objective of this paper is to propose a new approach for designing passive LC compensators by using the penalty function method as an optimization tool. The performance of the cost-effective passive LC compensator for a constant load depends on the appropriate inductor and capacitor selection. Several design methods are reviewed and a novel design methodology is proposed in this paper. By using the proposed method, the designer can quickly find appropriate parameter values to meet the desired circuit performance. Simulated results show that an appropriate combination of the inductor and capacitor selected by the proposed method can meet the desired power-quality requirement. Different cases of design examples are shown in this paper to verify the performance of the proposed design methodology
Sobre a formação matemática dos professores do 1.º ciclo: conhecer e compreender as possíveis dificuldades
No full textEste artigo insere-se num projecto de investigação mais amplo, onde se pretende fazer um estudo sobre a formação matemática dos (futuros) professores do primeiro
ciclo. Em Portugal, contrariamente ao que se passa em outros países, esta formação nem sempre mereceu uma atenção particular por parte da comunidade cientifica. Tal facto pode ser constatado por uma análise de revistas da especialidade, como por exemplo, em Portugal, a Gazeta de Matemática ou internacionalmente, a L’enseignement mathématique.
Actualmente porém a situação parece apresentar sinais de algumas modificações e a necessidade de um estudo nacional sobre a formação matemática dos professores do primeiro ciclo parece-nos indispensável.Um bom ponto de partida para estudar o tipo de formação matemática a oferecer aos futuros professores do ensino básico afigurasse-nos ser uma análise científica detalhada do programa de Matemática do 1.º ciclo. Neste artigo, após a elaboração de alguns comentários a aspectos genéricos deste
programa, vamos identificar algumas características intrínsecas desses conteúdos matemáticos e as prováveis implicações ao nível da sua aprendizagem e por conseguinte do seu ensino
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