Power Electronics Interfaces for DC-Microgrids Applications

The decentralization of power generation has become a topic of high interest for industry and academia. The integration of stochastic Renewable Energy Sources (RESs) at the distribution level is facilitated by incorporating them into a Microgrid. In this scenario, DC-Microgrids are a good option since many RESs, such as photovoltaic and fuel cell, and energy storage units present DC output characteristics. Also, the efficiency of the DC-DC interfaces tends to be higher than in DC-AC and issues such as frequency regulation, reactive power control and synchronization are avoided. The control of segments of the distribution system as a Microgrid also helps with the deployment of new large loads such as Electric Vehicles (EVs). However, the intermittent nature of RESs presents a natural challenge for the large scale implementation of DC-Microgrids. Since weather and nature conditions (such as wind, tides, and sunshine) can be rather unpredictable and are uncorrelated with power consumption needs, DC-Microgrids based on RESs must be strongly supported by fast acting Energy Storage Systems (ESSs) to balance supply/demand and assure high power quality to the system. Among these storage devices, Supercapacitors (SCs) have seen a rise in their popularity for power quality improvement in DC-Microgrids. SCs are devices with a high power density and high charge/discharge rates that can be used to provide sudden bursts of power by managing currents with high gradients, acting as dynamic devices to either supply the necessary power or demand extra power within the DC-Microgrid. Thus, the interface of such system requires that both the power converter topology and the control scheme present the right set of features. Therefore, this PhD research work discusses the main aspects regarding the operation of power electronics converters and suitable control laws considering the characteristics of the mentioned application. These aspects include: the modulation scheme employed, steady-state characteristics of the power converters and modelling/design of a suitable control law. First, a unified controller for multi-state operation of the traditional 4-switch Bidirectional Buck-Boost DC-DC converter is proposed. It employs a carrier-based modulation scheme with three modulation signals that allows the converter to operate in all four possible states and eight different modes of operation. A mathematical model is developed for devising a multi-variable control scheme using feedback linearization. This allows the design of control loops with simple PI controllers that can be used for all multi-state modes under a wide range of operating conditions with the same performance. Then, to deal with the limitations presented by the previous converter, a novel bidirectional DC-DC converter based on a Tapped-Inductor (TI) for higher voltage gain at moderate duty cycles is proposed. What is more, the direction of the current in the intermediate inductor of the new topology does not need to be reversed for power flow reversal, leading to a faster action and avoiding singularities in the control law. Besides, it can employ a similar multi-state and multi-variable modulation scheme that eliminates the Right Half-Plane (RHP) zero, common in Boost-type converters. A systematic approach for deriving control laws for the TI current and output voltage based on exact state feedback linearization is discussed. The performance of the proposed control scheme is verified by simulation for a SC-based ESS

The LIM domain protein UNC-95 is required for the assembly of muscle attachment structures and is regulated by the RING finger protein RNF-5 in C. elegans

Here, we describe a new muscle LIM domain protein, UNC-95, and identify it as a novel target for the RING finger protein RNF-5 in the Caenorhabditis elegans body wall muscle. unc-95(su33) animals have disorganized muscle actin and myosin-containing filaments as a result of a failure to assemble normal muscle adhesion structures. UNC-95 is active downstream of PAT-3/β-integrin in the assembly pathways of the muscle dense body and M-line attachments, and upstream of DEB-1/vinculin in the dense body assembly pathway. The translational UNC-95::GFP fusion construct is expressed in dense bodies, M-lines, and muscle–muscle cell boundaries as well as in muscle cell bodies. UNC-95 is partially colocalized with RNF-5 in muscle dense bodies and its expression and localization are regulated by RNF-5. rnf-5(RNAi) or a RING domain deleted mutant, rnf-5(tm794), exhibit structural defects of the muscle attachment sites. Together, our data demonstrate that UNC-95 constitutes an essential component of muscle adhesion sites that is regulated by RNF-5

SUMOylation controls stem cell proliferation and regional cell death through Hedgehog signaling in planarians.

Mechanisms underlying anteroposterior body axis differences during adult tissue maintenance and regeneration are poorly understood. Here, we identify that post-translational modifications through the SUMO (Small Ubiquitin-like Modifier) machinery are evolutionarily conserved in the Lophotrocozoan Schmidtea mediterranea. Disruption of SUMOylation in adult animals by RNA-interference of the only SUMO E2 conjugating enzyme Ubc9 leads to a systemic increase in DNA damage and a remarkable regional defect characterized by increased cell death and loss of the posterior half of the body. We identified that Ubc9 is mainly expressed in planarian stem cells (neoblasts) but it is also transcribed in differentiated cells including neurons. Regeneration in Ubc9(RNAi) animals is impaired and associated with low neoblast proliferation. We present evidence indicating that Ubc9-induced regional cell death is preceded by alterations in transcription and spatial expression of repressors and activators of the Hedgehog signaling pathway. Our results demonstrate that SUMOylation acts as a regional-specific cue to regulate cell fate during tissue renewal and regeneration

TIP49b, a Regulator of Activating Transcription Factor 2 Response to Stress and DNA Damage

Activating transcription factor 2 (ATF2/CRE-BP1) is implicated in transcriptional control of stress-responsive genes. A yeast two-hybrid screen identified TBP-interacting protein 49b (TIP49b), a component of the INO80 chromatin-remodeling complex, as a novel ATF2-interacting protein. TIP49b's association with ATF2 is phosphorylation dependent and requires amino acids 150 to 248 of ATF2 (ATF2150–248), which are implicated in intramolecular inhibition of ATF2 transcriptional activities. Forced expression of TIP49b efficiently attenuated ATF2 transcriptional activities under normal growth conditions as well as after UV treatment, ionizing irradiation, or activation of p38 kinase, all of which induced ATF2 phosphorylation and increased TIP49b-ATF2 association. Constitutive expression of ATF2150–248 peptide outcompeted TIP49b interaction with ATF2 and alleviated the suppression of ATF2 transcriptional activities. Expression of ATF2150–248 in fibroblasts or melanoma but not in ATF2-null cells caused a profound G2M arrest and increased degree of apoptosis following irradiation. The interaction between ATF2 and TIP49b constitutes a novel mechanism that serves to limit ATF2 transcriptional activities and highlights the central role of ATF2 in the control of the cell cycle and apoptosis in response to stress and DNA damage

Classification of Dust Days by Satellite Remotely Sensed Aerosol Products

Considerable progress in satellite remote sensing (SRS) of dust particles has been seen in the last decade. From an environmental health perspective, such an event detection, after linking it to ground particulate matter (PM) concentrations, can proxy acute exposure to respirable particles of certain properties (i.e. size, composition, and toxicity). Being affected considerably by atmospheric dust, previous studies in the Eastern Mediterranean, and in Israel in particular, have focused on mechanistic and synoptic prediction, classification, and characterization of dust events. In particular, a scheme for identifying dust days (DD) in Israel based on ground PM10 (particulate matter of size smaller than 10 nm) measurements has been suggested, which has been validated by compositional analysis. This scheme requires information regarding ground PM10 levels, which is naturally limited in places with sparse ground-monitoring coverage. In such cases, SRS may be an efficient and cost-effective alternative to ground measurements. This work demonstrates a new model for identifying DD and non-DD (NDD) over Israel based on an integration of aerosol products from different satellite platforms (Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI)). Analysis of ground-monitoring data from 2007 to 2008 in southern Israel revealed 67 DD, with more than 88 percent occurring during winter and spring. A Classification and Regression Tree (CART) model that was applied to a database containing ground monitoring (the dependent variable) and SRS aerosol product (the independent variables) records revealed an optimal set of binary variables for the identification of DD. These variables are combinations of the following primary variables: the calendar month, ground-level relative humidity (RH), the aerosol optical depth (AOD) from MODIS, and the aerosol absorbing index (AAI) from OMI. A logistic regression that uses these variables, coded as binary variables, demonstrated 93.2 percent correct classifications of DD and NDD. Evaluation of the combined CART-logistic regression scheme in an adjacent geographical region (Gush Dan) demonstrated good results. Using SRS aerosol products for DD and NDD, identification may enable us to distinguish between health, ecological, and environmental effects that result from exposure to these distinct particle populations

Rapid interrogation of the physical and chemical characteristics of salbutamol sulphate aerosol from a pressurised metered-dose inhaler (pMDI)

Individual micron-sized solid particles from a Salamols pharmaceutical inhaler are stably captured in air using an optical trap for the first time. Raman spectroscopy of the levitated particles allows online interrogation of composition and deliquescent phase change within a high humidity environment that mimics the particle’s travel from inhaler to lun

Dynamics of aerosol size during inhalation : Hygroscopic growth of commercial nebulizer formulations

We thank the Elizabeth Blackwell Institute (EBI) for financial support through the EBI Early Career Research Fellowship awarded to AEH, and the EPSRC for financial support through a Leadership Fellowship awarded to JPR (grant reference EP/G007713/1). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are creditedThe size of aerosol particles prior to, and during, inhalation influences the site of deposition within the lung. As such, a detailed understanding of the hygroscopic growth of an aerosol during inhalation is necessary to accurately model the deposited dose. In the first part of this study, it is demonstrated that the aerosol produced by a nebulizer, depending on the airflows rates, may experience a (predictable) wide range of relative humidity prior to inhalation and undergo dramatic changes in both size and solute concentration. A series of sensitive single aerosol analysis techniques are then used to make measurements of the relative humidity dependent thermodynamic equilibrium properties of aerosol generated from four common nebulizer formulations. Measurements are also reported of the kinetics of mass transport during the evaporation or condensation of water from the aerosol. Combined, these measurements allow accurate prediction of the temporal response of the aerosol size prior to and during inhalation. Specifically, we compare aerosol composed of pure saline (150 mM sodium chloride solution in ultrapure water) with two commercially available nebulizer products containing relatively low compound doses: Breath, consisting of a simple salbutamol sulfate solution (5 mg/2.5 mL; 1.7 mM) in saline, and Flixotide Nebules, consisting of a more complex stabilized fluticasone propionate suspension (0.25 mg/mL; 0.5 mM in saline. A mimic of the commercial product Tobi (60 mg/mL tobramycin and 2.25 mg/mL NaC1, pH 5.5-6.5) is also studied, which was prepared in house. In all cases, the presence of the pharmaceutical was shown to have a profound effect on the magnitude, and in some cases the rate, of the mass flux of water to and from the aerosol as compared to saline. These findings provide physical chemical evidence supporting observations from human inhalation studies, and suggest that using the growth dynamics of a pure saline aerosol in a lung inhalation model to represent nebulizer formulations may not be representative of the actual behavior of the aerosolized drug solutions. (C) 2014 Published by Elsevier B.V.Peer reviewe

Controlled sumoylation of the mevalonate pathway enzyme HMGS-1 regulates metabolism during aging

Many metabolic pathways are critically regulated during development and aging but little is known about the molecular mechanisms underlying this regulation. One key metabolic cascade in eukaryotes is the mevalonate pathway. It catalyzes the synthesis of sterol and nonsterol isoprenoids, such as cholesterol and ubiquinone, as well as other metabolites. In humans, an age-dependent decrease in ubiquinone levels and changes in cholesterol homeostasis suggest that mevalonate pathway activity changes with age. However, our knowledge of the mechanistic basis of these changes remains rudimentary. We have identified a regulatory circuit controlling the sumoylation state of Caenorhabditis elegans HMG-CoA synthase (HMGS-1). This protein is the ortholog of human HMGCS1 enzyme, which mediates the first committed step of the mevalonate pathway. In vivo, HMGS-1 undergoes an age-dependent sumoylation that is balanced by the activity of ULP-4 small ubiquitin-like modifier protease. ULP-4 exhibits an age-regulated expression pattern and a dynamic cytoplasm-to-mitochondria translocation. Thus, spatiotemporal ULP-4 activity controls the HMGS-1 sumoylation state in a mechanism that orchestrates mevalonate pathway activity with the age of the organism. To expand the HMGS-1 regulatory network, we combined proteomic analyses with knockout studies and found that the HMGS-1 level is also governed by the ubiquitin–proteasome pathway. We propose that these conserved molecular circuits have evolved to govern the level of mevalonate pathway flux during aging, a flux whose dysregulation is associated with numerous age-dependent cardiovascular and cancer pathologies

Inclusão educacional: a avaliação psicoeducacional no contexto escolar e as adaptações curriculares de pequeno porte

The educational inclusion of the target audience for Special Education is a matter of discussion among teachers, administrators, specialists, researchers and family of these attendees. This study aims to discuss some of these demands, pursuing to diagnose how the Basic Education teachers, in different areas of knowledge, position themselves in face of some educational inclusion challenges related to the identification of the student with special needs; to the process of the Psychoeducational Assessment in the School Context; and minor curricular adaptations. We endeavor to understand how the Psychoeducational Assessment in the School Context promotes/sustains the minor curricular adaptations and its repercussion in the pedagogical practice of basic education teachers. For the analysis and discussion of its outcomes, we use Bardin Content Analysis (2011). The results show practices that are still far away from an effective educational inclusion, in which there is a detachment between the Specialized Educational Attendance and the work of the common education teacher, who does not take part in the process and sees the specialist teacher as the responsible one for the Psychoeducational Assessment in the School Context. The results reveal the importance of educating and training the teacher towards the educational inclusion, which demands a shared effort, in which the final goal must be the education itself, in all its dynamics, believing that the school has the responsibility to develop academic, cognitive, affective-emotional and social capacities of all students, with or without any special needs.A inclusão educacional do público alvo da Educação Especial configura-se como objeto de discussão entre professores, gestores, especialistas, pesquisadores e familiares desse público. Esse estudo objetiva tratar de algumas dessas demandas, visando diagnosticar como professores da Educação Básica, dentro de diferentes áreas do conhecimento, se posicionam frente a alguns dos desafios da inclusão educacional, relacionados a identificação do aluno com necessidades educacionais especiais; ao processo de Avaliação Psicoeducacional no Contexto Escolar e as adaptações curriculares de pequeno porte. Busca-se compreender, utilizando-se, para análise e discussão dos resultados, a Análise de Conteúdo de Bardin (2011), como a Avaliação Psicoeducacional no Contexto Escolar promove/sustenta as adaptações curriculares de pequeno porte e qual sua repercussão na prática pedagógica dos professores da Educação Básica. Os resultados encontrados remetem a práticas ainda distantes de uma efetiva inclusão educacional, onde há o distanciamento entre o Atendimento Educacional Especializado (AEE) e o trabalho do professor do ensino comum, que vê no professor especialista o responsável pela Avaliação Psicoeducacional no Contexto Escolar, não se colocando dentro do processo. Revelam, a importância da formação e capacitação do professor, voltados a inclusão educacional que exige um trabalho compartilhado, onde a finalidade deve ser a educação, em toda sua dinâmica, acreditando que a escola tem como responsabilidade, desenvolver as capacidades acadêmicas, cognitivas, afetivo-emocionais e sociais de todos os alunos com deficiência ou não