Modeling of Ion/Target Interactions in Plasma Facing Components of Fusion Reactor

Nuclear fusion is a promising source of clean energy that can be one of the key future suppliers of the world’s increasing power demand. One of today’s main challenges faced by scientists and engineers regarding nuclear reactors is to design plasma-facing components (PFCs) that can withstand extreme conditions of temperature, pressure, and ions/particles irradiation. Material evolution and damage of PFCs are strongly related to the bombardment and diffusion processes of ions resulting from fusion fuel, i.e., deuterium and tritium and reaction products, i.e., helium. However, work is still needed in order to understand fuel diffusion in the presence of helium effects and damage produced in heterogeneous media of potential PFCs. This study simulates the diffusion of atoms in an alloy of changing solute concentration in an environment similar to that of a nuclear fusion reactor. The diffusion equation was solved numerically while taking into account the “potential diffusion” present in heterogeneous materials, as it was described analytically in recent studies. The solution was implemented in Fortran 90 code using SRIM software as an input generator and taking parameters found in literature. Our results show that heterogeneous membranes can greatly shift the deuterium concentration profile towards the vanadium back surface, increasing the material\u27s permeability. These outcomes suggest that vanadium alloys with heterogeneous solute concentration distribution should be empirically analyzed in order to understand how these concentration shifts affect material properties and fuel retention

Quantitative Tissue Spectroscopy of Near Infrared Fluorescent Nanosensor Implants

Implantable, near infrared (nIR) fluorescent nanosensors are advantageous for in vivo monitoring of biological analytes since they can be rendered selective for particular target molecule while utilizing their unique optical properties and the nIR tissue transparency window for information transfer without an internal power source or telemetry. However, basic questions remain regarding the optimal encapsulation platform, geometrical properties, and concentration ranges required for effective signal to noise ratio through biological tissue. In this work, we systematically explore these variables quantitatively to optimize the performance of such optical nanosensors for biomedical applications. We investigate both alginate and polyethylene glycol (PEG) as model hydrogel systems, encapsulating d(GT)[subscript 15] ssDNA-wrapped single walled carbon nanotubes (SWNT) as model fluorescent nanoparticle sensors, responsive to riboflavin. Hydrogel sensors implanted 0.5 mm into thick tissue samples cause 50% reduction of initial fluorescence intensity, allowing an optical detection limit of 5.4 mm and 5.1 mm depth in tissue for alginate and PEG gels, respectively, at a SWNT concentration of 10 mg L−1, and 785 nm laser excitation of 80 mW and 30 s exposure. These findings are supported with in vivo nIR fluorescent imaging of SWNT hydrogels implanted subcutaneously in mice. For the case of SWNT, we find that the alginate system is preferable in terms of emission intensity, sensor response, rheological properties, and shelf life.National Institutes of Health (U.S.) (T32 Training Grant in Environmental Toxicology ES007020)National Cancer Institute (U.S.) (Grant P01 CA26731)National Institute of Environmental Health Sciences (Grant P30 ES002109)Arnold and Mabel Beckman Foundation (Young Investigator Award)National Science Foundation (U.S.) (Presidential Early Career Award for Scientists and Engineers)MIT-Technion FellowshipSamsung Scholarship FoundationSanofi Aventis (Firm) (Biomedical Innovation Grant

Cultivando saberes: hortas familiares, segurança alimentar e práticas educativas no planalto serrano catarinense

Este artigo analisa o processo de implementação de propostas de Agricultura Urbana no município de Curitibanos/SC. A partir de 2013 o PET: Ciências Rurais (UFSC) inicia o projeto na perspectiva de duplicar a tecnologia social proposta pelo LECERA/CCA/UFSC, que tem como um de seus objetivos o incentivo a formação de hortas em espaços urbanos. O trabalho iniciou pelo bairro São Luiz em parceria com organizações da sociedade civil, entidades governamentais e religiosas, foi ampliado em 2016 com atividades na APAE/Curitibanos. Esse projeto pauta-se em experiências solidárias articulando práticas e incentivos a realização de hortas nas famílias e ações educativas através de hortas e jardins terapêuticos. Desta forma contribui para produção alimentar familiar, com inferências na educação alimentar e nutricional, bem como, delineando espaços culturais e interacionais entre os jovens e suas famílias. Enquanto resultado observa-se a contribuição para processos de inclusão social, saúde, qualidade de vida e cidadania, com a consequente valorização do conhecimento, saberes e fazeres na produção alimentar e nas práticas de economia solidária. É nesse sentido que muitas experiências envolvendo a construção de hortas comunitárias e de agricultura urbana são realizados

Development of the Low Frequency Telescope Focal Plane Detector Modules for LiteBIRD

LiteBIRD is a JAXA-led strategic large-class satellite mission designed to measure the polarization of the cosmic microwave background and Galactic foregrounds from 34 to 448 GHz across the entire sky from L2 in the late 2020s. The scientific payload includes three telescopes which are called the low-, mid-, and high-frequency telescopes each with their own receiver that covers a portion of the mission's frequency range. The low frequency telescope will map synchrotron radiation from the Galactic foreground and the cosmic microwave background. We discuss the design, fabrication, and characterization of the low-frequency focal plane modules for low-frequency telescope, which has a total bandwidth ranging from 34 to 161 GHz. There will be a total of 4 different pixel types with 8 overlapping bands to cover the full frequency range. These modules are housed in a single low-frequency focal plane unit which provides thermal isolation, mechanical support, and radiative baffling for the detectors. The module design implements multi-chroic lenslet-coupled sinuous antenna arrays coupled to transition edge sensor bolometers read out with frequency-domain mulitplexing. While this technology has strong heritage in ground-based cosmic microwave background experiments, the broad frequency coverage, low optical loading conditions, and the high cosmic ray background of the space environment require further development of this technology to be suitable for LiteBIRD. In these proceedings, we discuss the optical and bolometeric characterization of a triplexing prototype pixel with bands centered on 78, 100, and 140 GHz.Comment: SPIE Astronomical Telescope + Instrumentation (AS22

Refletindo a extensão e suas práticas - PETGEOUDESC - educação e pesquisa

Este artigo objetiva a reflexão e o esclarecimento sobre o que é e como tem sido realizada a extensão universitária. Para cumprir tal objetivo buscamos entender primeiro o que diz a Constituição Brasileira a respeito e como teve inicio a prática extensionista no Brasil. Em seguida abordamos as formar tradicionais de se fazer extensão universitária. Depois, de posse de alguns conceitos e com algumas reflexões já realizadas abordamos formas de extensão que consideramos de sucesso. Por últimos analisamos as atividades de extensão realizadas pelso grupos PET

In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes

Single-walled carbon nanotubes are particularly attractive for biomedical applications, because they exhibit a fluorescent signal in a spectral region where there is minimal interference from biological media. Although single-walled carbon nanotubes have been used as highly sensitive detectors for various compounds, their use as in vivo biomarkers requires the simultaneous optimization of various parameters, including biocompatibility, molecular recognition, high fluorescence quantum efficiency and signal transduction. Here we show that a polyethylene glycol ligated copolymer stabilizes near-infrared-fluorescent single-walled carbon nanotubes sensors in solution, enabling intravenous injection into mice and the selective detection of local nitric oxide concentration with a detection limit of 1 µM. The half-life for liver retention is 4 h, with sensors clearing the lungs within 2 h after injection, thus avoiding a dominant route of in vivo nanotoxicology. After localization within the liver, it is possible to follow the transient inflammation using nitric oxide as a marker and signalling molecule. To this end, we also report a spatial-spectral imaging algorithm to deconvolute fluorescence intensity and spatial information from measurements. Finally, we demonstrate that alginate-encapsulated single-walled carbon nanotubes can function as implantable inflammation sensors for nitric oxide detection, with no intrinsic immune reactivity or other adverse response for more than 400 days.National Institutes of Health (U.S.) (T32 Training Grant in Environmental Toxicology ES007020)National Cancer Institute (U.S.) (Grant P01 CA26731)National Institute of Environmental Health Sciences (Grant P30 ES002109)Arnold and Mabel Beckman Foundation (Young Investigator Award)National Science Foundation (U.S.). Presidential Early Career Award for Scientists and EngineersScientific and Technological Research Council of Turkey (TUBITAK 2211 Research Fellowship Programme)Scientific and Technological Research Council of Turkey (TUBITAK 2214 Research Fellowship Programme)Middle East Technical University. Faculty Development ProgrammeSanofi Aventis (Firm) (Biomedical Innovation Grant

A New Species of River Dolphin from Brazil or:How Little Do We Know Our Biodiversity

True river dolphins are some of the rarest and most endangered of all vertebrates. They comprise relict evolutionary lineages of high taxonomic distinctness and conservation value, but are afforded little protection. We report the discovery of a new species of a river dolphin from the Araguaia River basin of Brazil, the first such discovery in nearly 100 years. The species is diagnosable by a series of molecular and morphological characters and diverged from its Amazonian sister taxon 2.08 million years ago. The estimated time of divergence corresponds to the separation of the Araguaia-Tocantins basin from the Amazon basin. This discovery highlights the immensity of the deficit in our knowledge of Neotropical biodiversity, as well as vulnerability of biodiversity to anthropogenic actions in an increasingly threatened landscape. We anticipate that this study will provide an impetus for the taxonomic and conservation reanalysis of other taxa shared between the Araguaia and Amazon aquatic ecosystems, as well as stimulate historical biogeographical analyses of the two basins