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Design and Optimization of a GaN GIT Based PFC Boost Converter

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Chinese Journal of Electrical Engineering 2017年第3期3卷 34-43页

作者： Wenbo Wang Frans Pansier Jelena Popovic J.A.ferreira Delft University of Technology DelftThe Netherlands

The advent of GaN power devices brings the possibility of pushing up frequencies of power electronics system beyond the capacity of conventional Si *** harvest the high frequency operation benefits of GaN technology,not only GaN devices should be used optimally by providing proper switching and conduction conditions to best accommodate parasitic elements inherent with the devices,other components should also be capable of facilitating high frequency *** this paper,PFC boost converter is used as a platform to harvest the benefits of GaN technology and,at the same time,to uncover the limitations in pushing power electronics systems up.A 600W PFC boost converter with a maximum switching frequency of 3MHz is designed and implemented,which reached an average efficiency of 98.5%.The results indicate that,when properly used,a GaN PFC boost converter could operate at a frequency that is beyond the reach of conventional Si *** well,with availability of GaN devices,high frequency operation of power electronics systems is no longer limited by the lack of switching devices but by practical issues *** frequency magnetic materials,high frequency controllers,etc.

关键词： GaN GIT boost converter PFC high frequency design optimization

Conflicting Discourses on Wildfire Risk and the Role of Local Media in the Amazonian and Temperate Forests

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International Journal of Disaster Risk Science 2019年第4期10卷 529-543页

作者： Nathalia Thais Cosmo da Silva Urbano FraPaleo Jose Ambrosio ferreira Neto Departamento de Economia Rural Universidade Federal de VicosaCampus UniversitarioEdificio Edson Potsch MagalhaesVicosaMG 36570-900Brazil School of Social Sciences and Humanities University of ExtremaduraCampus of Caceres City10071 CaceresSpain

This article examines how risk is communicated by different actors,particularly local print newspapers and actors at the community level,in two different geographical contexts that are severely affected by wildfires—the Brazilian Amazon and Atlantic *** analyzed how wildfire risk is framed in local print media and local actor discourse to elucidate how wildfire risk is interpreted and aimed to identify the main priorities of these risk governance *** main findings reveal that the presentation of wildfire as a spectacle is a serious obstacle to the promotion of coherent risk governance and social learning,which involves recognizing wildfire risk as a social,political,economic,and environmental *** risk governance should communicate the multifaceted nature of risk and stimulate dialogue and negotiation among all actors to build consensus regarding land use and the creation of risk.

关键词： Discourse analysis Framing Galicia Local media Risk communication Rondonia Wildfire risk

Cell-free therapy:a neuroregenerative approach to sensory neuropathy?

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Neural Regeneration Research 2019年第8期14卷 1383-1384页

作者： Afranio ferreira Evangelista Milena Botelho Pereira Soares Cristiane Flora Villarreal Instituto Gongalo Moniz Fundacao Oswaldo Cruz Salvador BA Brazil Faculdade de Farmacia Universidade Federal da Bahia Salvador BA Brazil

Stem cells are considered as key therapeutic tools in the field of regenerative medicine. In the last decade, based on a growing body of knowledge about their mechanisms of action, a new way of exploring the therapeutic potential of stem cells without the need for cell transplantation has been evidenced. This approach, called cell-free therapy, uses stem cells as a source of therapeutic molecules rather than the therapeutic agent per se, and several studies have shown relevant therapeutic effects under a variety of experimental conditions, including nervous system disorders.

关键词： Cell-free therapy neuroregenerative approach sensory neuropathy

Discovery of the marine Eocene in the northern South China Sea

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National Science Review 2019年第5期6卷 881-886页

作者： Zhimin Jian Haiyan Jin Michael A Kaminski Fabricio ferreira Baohua Li Pai-Sen Yu State Key Laboratory of Marine Geology Tongji University Geosciences Department King Fahd University of Petroleum and Minerals Institute for Geosciences Universidade Federal Fluminense Nanjing Institute of Geology and Paleontology Chinese Academy of Sciences Applied Research Laboratories(NARLabs) Taiwan Ocean Research Institute(TORI)

The nature of the Eocene stratigraphy of the South China Sea (SCS) has been a mystery for *** the southern SCS, the Eocene system with marine deposits is often considered as representing part of the ‘Proto-South Chin... 详细信息

关键词： SCS Sr Discovery of the marine Eocene in the northern South China Sea China

Contribution of glial cells to the neuroprotective effects triggered by repetitive magnetic stimulation:a systematic review

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Neural Regeneration Research 2024年第1期19卷 116-123页

作者： Susana A.ferreira Nuno Pinto Inês Serrenho Maria Vaz Pato Graça Baltazar Centro de Investigação em Ciências da Saúde(CICS-UBI) Universidade da Beira InteriorCovilhãPortugal Faculdade de Ciências da Saúde Universidade da Beira InteriorCovilhãPortugal GRUBI-Systematic Reviews Group University of Beira InteriorCovilhãPortugal

Repetitive transcranial magnetic stimulation has been increasingly studied in different neurological diseases,and although most studies focus on its effects on neuronal cells,the contribution of nonneuronal cells to the improvement trigge red by repetitive transcranial magnetic stimulation in these diseases has been increasingly *** systematically review the effects of repetitive magnetic stimulation on non-neuronal cells two online *** of Science and PubMed were searched fo r the effects of high-frequency-repetitive transcranial magnetic stimulation,low-frequencyrepetitive transcranial magnetic stimulation,intermittent theta-bu rst stimulation,continuous thetaburst stimulation,or repetitive magnetic stimulation on non-neuronal cells in models of disease and in unlesioned animals or cells.A total of 52 studies were *** protocol more frequently used was high-frequency-repetitive magnetic stimulation,and in models of disease,most studies report that high-frequency-repetitive magnetic stimulation led to a decrease in astrocyte and mic roglial reactivity,a decrease in the release of pro-inflammatory cyto kines,and an increase of oligodendrocyte *** trend towards decreased microglial and astrocyte reactivity as well as increased oligodendrocyte proliferation occurred with intermittent theta-burst stimulation and continuous theta-burst *** papers analyzed the low-frequency-repetitive transcranial magnetic stimulation protocol,and the parameters evaluated were restricted to the study of astrocyte reactivity and release of pro-inflammatory cytokines,repo rting the absence of effects on these paramete *** what concerns the use of magnetic stimulation in unlesioned animals or cells,most articles on all four types of stimulation reported a lack of *** is also important to point out that the studies were developed mostly in male rodents,not evaluating possible diffe rential effects of repetitive transcranial magneti

关键词： astrocyte glia high-frequency repetitive magnetic stimulation inflammation low-frequency repetitive magnetic stimulation microglia neurologic disorders oligodendrocyte repetitive magnetic stimulation theta-burst stimulation

Droplet-based bioprinting enables the fabrication of cell–hydrogel–microfibre composite tissue precursors

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Bio-Design and Manufacturing 2022年第3期5卷 512-528页

作者： Marcin Kotlarz Ana M.ferreira Piergiorgio Gentile Stephen J.Russell Kenneth Dalgarno School of Engineering Newcastle UniversityNewcastle upon Tyne NE17RUUK School of Design University of LeedsLeeds LS29JTUK

Composites offer the option of coupling the individual benefits of their constituents to achieve unique material properties,which can be of extra value in many tissue engineering *** combining hydrogelswith fibre-based scaffolds can create tissue constructs with enhanced biological and structural ***,developing efficient and scalable approaches to manufacture such composites is ***,we use a droplet-based bioprinting system called reactive jet impingement(ReJI)to integrate a cell-laden hydrogel with a microfibrous *** system uses microvalves connected to different bioink reservoirs and directed to continuously jet bioink droplets at one another in mid-air,where the droplets react and form a hydrogel that lands on a microfibrous ***–hydrogel–fibre composites are produced by embedding human dermal fibroblasts at two different concentrations(5×10^(6) and 30×10^(6) cells/mL)in a collagen–alginate–fibrin hydrogel matrix and bioprinted onto a fibre-based *** results show that both types of cell–hydrogel–microfibre composite maintain high cell viability and promote cell–cell and cell–biomaterial *** lower fibroblast density triggers cell proliferation,whereas the higher fibroblast density facilitates faster cellular organisation and infiltration into the ***,the fibrous component of the composite is characterised by high swelling properties and the quick release of calcium *** data indicate that the created composite constructs offer an efficient way to create highly functional tissue precursors for laminar tissue engineering,particularly for wound healing and skin tissue engineering applications.

关键词： Bioprinting Hydrogel–fibre composites High-cell-density hydrogels Composite manufacturing

Extreme rain event highlights the lack of governance to face climate change in the Southeastern coast of Brazil

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Geography and Sustainability 2024年第1期5卷 29-32页

作者： M.L.ferreira Postgraduate Program in Architecture and Urban Planning University of Varzea GrandeMT 78118-900Brazil

New rainfall records were registered in the southeastern region of Brazil during February *** amount of rain in the north coast region of the State of São Paulo was more than 650 mm in less than two *** and tragedies with a socioeconomically vulnerable population marked this climatic *** country has a regulatory system that suggests the elaboration and implementation of municipal public policies aimed at territorial organization,environmental conservation,and the prevention of disasters induced by natural *** addition,both federal and state funds earmarked for such hazard's prevention have been underutilized over the last *** addition to this current devastating climate episode,other events were registered in this decade,reinforcing that financial governance is a key challenge to face the climate crisis in *** predicted future extreme events in different regions of Brazil will require a different governance system to minimize social inequality,seek sustainable alternatives for urban environments and manage to adapt cities for the challenges posed by climate change.

关键词： Disaster risk Environmental public policies Public funds Territorial planning

Tweaking the immune system as an adjuvant for the treatment of retinal degenerations

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Annals of Eye Science 2017年第1期2卷 53-56页

作者： Tiago Santos-ferreira Marius Ader Technische Universität Dresden Center for Regenerative Therapies Dresden(CRTD)DresdenGermany

Blinding diseases such as photoreceptor degenerations are debilitating conditions that severely impair daily lives of affected *** group of diseases are amenable to photoreceptor replacement therapies and recent transplantation studies provided proof-of-principle for functional recovery at the retinal and behavioral level,though the actual mechanism of repair still needs further *** immune system responds in several ways upon photoreceptor engraftment,resulting in T-cell and macrophage infiltrations and,consequently,decrease in graft *** studies on the role of the immune system suggest a detrimental effect in a therapeutic ***,the opposite idea wherein the immune system can be activated towards a protective state was also explored in other experimental ***,Neves and colleagues explored the potential of cross-species studies and,to a certain extent,the concept of a protective immune system in retinal degeneration and *** astrocyte-derived neurotrophic factor(MANF)was identified in this study as a novel factor that,by modulating the immune system,can slow down photoreceptor degeneration and improve transplantation outcome.

关键词： Immune modulation retina retinal degeneration photoreceptor transplantation retinal repair

Integrating an academic management system with blockchain:A case study

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Blockchain(Research and Applications) 2022年第4期3卷 81-90页

作者： Sergio Guerreiro Joao F.ferreira Tiago Fonseca Miguel Correia INESC-ID Rua Alves Redol 91000-029LisbonPortugal Instituto Superior Tecnico University of Lisbon1649-004LisbonPortugal

This paper reports the design,implementation,and experimental phases of the EU H2020 QualiChain pilot“Staffing the Public Sector—The Case of Portugal”.The overall purpose of this pilot is to ensure the authenticity and integrity of the diplomas for all involved stakeholders and therefore to contribute to solving the diploma counterfeiting and/or falsification that is a great threat to the recruitment of qualified *** main innovative aspect of this solution is the integration that is offered between an Academic Management System(the *** platform)and a Blockchain(Ethereum)to automatically deploy *** solution helps the involved stakeholders trust the diplomas *** case study involves four different stakeholders and studies,specifically,the increase in their satisfaction in terms of diploma control,diploma veracity,and diploma *** developed system was tested with external participants who were asked to follow a set of guidelines and complete a survey to assess their *** system interactions were recorded,and the data were *** results indicated that the participants successfully executed the guidelines and that a perception increase toward diploma control,veracity,and credibility was identified.

关键词： Blockchain University management system Authenticity Document verification Education certificate Ethereum Integrity Smart contrac