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Equilibrium and Disequilibrium of River Basins: Effects on Stream Captures in Serra do Mar and Serra da Mantiqueira, Brazil

NASA Astrophysics Data System (ADS)

DA Silva, L. M.

2015-12-01

Landscapes are mainly driven by river processes that control the dynamic reorganization of networks. Discovering and identifying whether river basins are in geometric equilibrium or disequilibrium requires an analysis of water divides, channels that shift laterally or expand upstream and river captures. Issues specifically discussed include the variation of drainage area change and erosion rates of the basins. In southeastern Brazil there are two main escarpments with extensive geomorphic surfaces: Serra do Mar and Serra da Mantiqueira Mountains. These landscapes are constituted of Neoproterozoic and early Paleozoic rocks, presenting steep escarpments with low-elevation coastal plains and higher elevation interior plateaus. To identify whether river basins and river profiles are in equilibrium or disequilibrium in Serra do Mar and Serra da Mantiqueira Mountains, we used the proxy (χ), evaluating the effect of drainage area change and erosion rates. We selected basins that drain both sides of these two main escarpments (oceanic and continental sides) and have denudation rates derived from pre-existing cosmogenic isotopes data (Rio de Janeiro, Paraná and Minas Gerais). Despite being an ancient and tectonically stable landscape, part of the coastal plain of Serra do Mar Mountain in Rio de Janeiro and Paraná is in geometric disequilibrium, with water divides moving in the direction of higher χ values. To achieve equilibrium, some basins located in the continental side are retracting and disappearing, losing area to the coastal basins. On the contrary, there are some adjacent sub-basins that are close to equilibrium, without strong contrasts in χ values. The same pattern was observed in Serra da Mantiqueira (Minas Gerais state), with stream captures and river network reorganization in its main rivers. The initial results suggest a strong contrast between erosion rates in the continental and the oceanic portions of the escarpments.
A long-term perspective on biomass burning in the Serra da Estrela, Portugal

NASA Astrophysics Data System (ADS)

Connor, Simon E.; Araújo, João; van der Knaap, Willem O.; van Leeuwen, Jacqueline F. N.

2012-11-01

Fire is currently perceived as a major threat to ecosystems and biodiversity in the mountains of the Mediterranean region. Portugal's highest mountain range, the Serra da Estrela, is one of the country's most important protected areas and also the most fire-prone. We present a ˜14,000-year fire history based on microscopic charred particles in an infilled glacial lake to better understand the antiquity of biomass burning and its effects on Mediterranean vegetation at the Atlantic margin. Results indicate the continuous occurrence of fire in the Serra da Estrela over the period of the record. Two periods of increased fire activity - around 12,000-11,000 calendar years before the present (cal. a BP) and 3500-2500 cal. a BP - were accompanied by major vegetation changes and followed by long periods of vegetation stabilisation. Cross-correlation analyses reveal that post-fire succession consistently began with herbaceous vegetation, followed by forest and shrubland stages. Past successional trends were often markedly different to those observed at present. Holocene climatic changes, including shifts in the North Atlantic Oscillation, played a pivotal role in the vegetation development and fire history of the Serra da Estrela. In the late Holocene, human use of fire became a major agent of vegetation change, accelerating the Holocene decline of forests.
Development of a benthic multimetric index for the Serra da Bocaina bioregion in Southeast Brazil.

PubMed

Baptista, D F; Henriques-Oliveira, A L; Oliveira, R B S; Mugnai, R; Nessimian, J L; Buss, D F

2013-08-01

Brazil faces a challenge to develop biomonitoring tools to be used in water quality assessment programs, but few multimetric indices were developed so far. This study is part of an effort to test and implement programs using benthic macroinvertebrates as bioindicators in Rio de Janeiro State. Our aim was first to test the Multimetric Index for Serra dos Órgãos (SOMI) for a different area--Serra da Bocaina (SB)--in the same ecoregion. We sampled 27 streams of different sizes and altitudes in the SB region. Despite the environmental similarities, results indicated biological differences between reference sites of the two regions. Considering these differences, we decided to develop an index specific for the SB region, the Serra da Bocaina Multimetric Index (MISB). We tested twenty-two metrics for sensitivity to impairment and redundancy, and six metrics were considered valid to integrate the MISB: Family Richness, Trichoptera Richness, % Coleoptera, % Diptera, IBE-IOC index, EPT / Chironomidae ratio. A test of the MISB in eleven sites indicated it was more related to land-use and water physico-chemical parameters than with altitude or stream width, being a useful tool for the monitoring and assessment of streams in the bioregion.
On Ensino de Astronomia nas Cidades de Ribeirão Pires e Rio Grande da Serra

NASA Astrophysics Data System (ADS)

Faria, R. Z.; Voelzke, M. R.

2007-08-01

Apesar da astronomia ser um dos temas indicados pelos Parâmetros Curriculares Nacionais, observa-se que poucas mudanças ocorreram desde a implementação do mesmo em sala de aula. A presente pesquisa diz respeito sobre como os tópicos de astronomia estão sendo abordados pelos professores no ensino médio. Optou-se por aplicar um questionário com os professores que ministram a disciplina de física. Os mesmos trabalham em escolas estaduais situadas nas cidades de Ribeirão Pires e Rio Grande da Serra, ambas subordinadas a Diretoria de Ensino de Mauá, no Estado de São Paulo. O questionário foi aplicado durante o 2° semestre de 2006. Até o momento os resultados são preliminares. Dos 82,0% dos professores que responderam ao questionário no município de Rio Grande da Serra, 66,7% não aplicaram nenhum tópico de astronomia, 77,8% não utilizaram qualquer tipo de programa computacional, 66,7% não utilizaram laboratório, que 77,8% nunca levaram os alunos a museus e ou planetários e que 66,7% não indicaram qualquer tipo de revista ou livro sobre astronomia aos seus alunos. No município de Ribeirão Pires, 53,3% dos professores responderam ao questionário, destes 75,0% não aplicaram nenhum tópico de astronomia, 93,8% não utilizaram qualquer tipo de programa computacional, 75,0% não utilizaram laboratório, 81,3% nunca levaram os alunos a museus e ou planetário e 56,3% não indicaram qualquer tipo de revista ou livro sobre astronomia ao seus alunos. Apesar da maioria dos professores reconhecerem que o conteúdo de astronomia influi na formação do jovem, os mesmos não incluem o tema em seus planejamentos escolares.
Paleoenvironmental significance of Holocene widespread deposition of continental carbonates in Serra da Bodoquena, West-central Brazil

NASA Astrophysics Data System (ADS)

Sallun Filho, W.; Ribeiro, L. M. A. L.; Sawakuchi, A. O.; Boggiani, P. C.

2016-12-01

Continental carbonates are used in paleoenvironmental reconstructions in several parts of the world. Tufas and unconsolidated micrites can provide valuable information about the environmental conditions during the period of deposition. When the deposits are discontinuous, their presence is evidence of a wet period with conditions that are favourable to deposition; the deposits can be a record of the hydrologic systems and paleoclimate of the period of deposition. Discontinuous periods of deposition could also indicate changes in hydrological conditions that were independent of changes in climate, such as by temporary activity of springs or changes in a river's position. Deposits of continental carbonates in Brazil are rare, but in the State of Mato Grosso do Sul, there are extensive deposits, especially in the Serra da Bodoquena karst area, which form expansive plains of unconsolidated micrite and phytohermal fluvial tufa. These deposits are collectively called the Serra da Bodoquena Formation. New radiocarbon and OSL ages confirm the Holocene as the age of The Serra da Bodoquena Formation which shows periods of more extensive deposition than today. Well-dated deposits of unconsolidated micrites from paleolakes indicate a deposition that occurred approximately 6,500 to 2,000 years BP. These deposits can be identified by their smooth textures, as compared to surrounding karst areas. Over the paleolake deposits, there are phytohermal tufas that can be identified adjacent to present-day fluvial channels, presenting irregular winding arcs and relict fluvial channels. These arcs correspond to the edges of ancient tufa dams. One ancient and inactive dam have radiocarbon ages between 680 and 895 cal years AD. Apparently, there was a distinct lack of deposition between approximately 2,000 and 1,270 years BP, after which the deposition is continuous. Younger radiocarbon ages of 670 to 550 cal years BP are found in terrace tufa deposits (present-day river channel). This work
Criteria for recognition and taphonomy of coprolites from the Serra da Galga Member, Marília Formation (Upper Cretaceous), Minas Gerais, Brazil

NASA Astrophysics Data System (ADS)

de Oliveira, Fábio Antônio; Santucci, Rodrigo Miloni

2017-10-01

The Cretaceous sedimentary rocks from Uberaba, Minas Gerais, have provided a rich vertebrate fauna unearthed from rocks of the Serra da Galga Member, Marília Formation, Bauru Group, of Maastrichtian age. Together with these fossils, a large number of coprolites have also been found from two main localities, here called the Peirópolis and Serra da Galga sites. During field trips carried out in the last few years, 340 samples have been collected, prepared, and analyzed in laboratory. By using parameters such as weight, density, mineralogical composition, and content, we identified 199 coprolites and 141 inorganic nodules (pseudocoprolites). The coprolites have been divided into four morphotypes, which suggest their producers varied in feeding strategies and size. The taphonomic study, based on morphological characters such as wear, presence of pebbles or pebble marks, and desiccation cracks, suggests they underwent temporal and spatial-mixing, and that the material from the Peirópolis Site were transported essentially by alluvial processes (alluvial fans), whereas the material from the Serra da Galga Site were reworked mainly by fluvial streams. The same taphonomic processes may well have affected other fossils from these sites, which are highly abundant in the rocks of this area. Because of that, this taphonomic aspect becomes an important parameter to be taken into account in future studies on the biota of the region.
Integrative overview of the herpetofauna from Serra da Mocidade, a granitic mountain range in northern Brazil.

PubMed

Moraes, Leandro J C L; de Almeida, Alexandre P; de Fraga, Rafael; Rojas, Rommel R; Pirani, Renata M; Silva, Ariane A A; de Carvalho, Vinícius T; Gordo, Marcelo; Werneck, Fernanda P

2017-01-01

The Brazilian mountain ranges from the Guiana Shield highlands are largely unexplored, with an understudied herpetofauna. Here the amphibian and reptile species diversity of the remote Serra da Mocidade mountain range, located in extreme northern Brazil, is reported upon, and biogeographical affinities and taxonomic highlights are discussed. A 22-days expedition to this mountain range was undertaken during which specimens were sampled at four distinct altitudinal levels (600, 960, 1,060 and 1,365 m above sea level) using six complementary methods. Specimens were identified through an integrated approach that considered morphological, bioacoustical, and molecular analyses. Fifty-one species (23 amphibians and 28 reptiles) were found, a comparable richness to other mountain ranges in the region. The recorded assemblage showed a mixed compositional influence from assemblages typical of other mountain ranges and lowland forest habitats in the region. Most of the taxa occupying the Serra da Mocidade mountain range are typical of the Guiana Shield or widely distributed in the Amazon. Extensions of known distribution ranges and candidate undescribed taxa are also recorded. This is the first herpetofaunal expedition that accessed the higher altitudinal levels of this mountain range, contributing to the basic knowledge of these groups in remote areas.
Integrative overview of the herpetofauna from Serra da Mocidade, a granitic mountain range in northern Brazil

PubMed Central

Moraes, Leandro J.C.L.; de Almeida, Alexandre P.; de Fraga, Rafael; Rojas, Rommel R.; Pirani, Renata M.; Silva, Ariane A.A.; de Carvalho, Vinícius T.; Gordo, Marcelo; Werneck, Fernanda P.

2017-01-01

Abstract The Brazilian mountain ranges from the Guiana Shield highlands are largely unexplored, with an understudied herpetofauna. Here the amphibian and reptile species diversity of the remote Serra da Mocidade mountain range, located in extreme northern Brazil, is reported upon, and biogeographical affinities and taxonomic highlights are discussed. A 22-days expedition to this mountain range was undertaken during which specimens were sampled at four distinct altitudinal levels (600, 960, 1,060 and 1,365 m above sea level) using six complementary methods. Specimens were identified through an integrated approach that considered morphological, bioacoustical, and molecular analyses. Fifty-one species (23 amphibians and 28 reptiles) were found, a comparable richness to other mountain ranges in the region. The recorded assemblage showed a mixed compositional influence from assemblages typical of other mountain ranges and lowland forest habitats in the region. Most of the taxa occupying the Serra da Mocidade mountain range are typical of the Guiana Shield or widely distributed in the Amazon. Extensions of known distribution ranges and candidate undescribed taxa are also recorded. This is the first herpetofaunal expedition that accessed the higher altitudinal levels of this mountain range, contributing to the basic knowledge of these groups in remote areas. PMID:29302235
Chestnut and lemon balm based ingredients as natural preserving agents of the nutritional profile in matured "Serra da Estrela" cheese.

PubMed

Carocho, Márcio; Barreira, João C M; Bento, Albino; Fernández-Ruiz, Virginia; Morales, Patricia; Ferreira, Isabel C F R

2016-08-01

Chestnut flowers, lemon balm plants and their decoctions were incorporated into "Serra da Estrela" cheese, to assess their potential to preserve its nutritional properties and provide new foodstuffs. The analyses were carried out after the normal ripening period of 1month and after 6months of storage. The most abundant nutrients were proteins and fats. The most abundant minerals were Ca and Na, while C16:0 and C18:1 were the main fatty acids. Saturated fatty acids were the most abundant, followed by the monounsaturated. Moisture seemed to be lower in the samples with the plants incorporated. The dried plants, when incorporated, seemed to be more efficient as preservers then the decoctions, although these better preserved the proteins. These plants can be regarded as promising natural preservers in foodstuffs cheese, given the preservation of key parameters and the slight impact on the nutritional value. Copyright © 2016 Elsevier Ltd. All rights reserved.
Microbiological characterization of Serra da Estrela cheese throughout its Appellation d'Origine Protégée region.

PubMed

Tavaria, F K; Malcata, F X

1998-05-01

The purpose of this study was to assess the typical microbiological quality of the most famous Portuguese traditional cheese, Serra da Estrela, and to assess its ripening time and geographical dependence. Ninety-six experimental cheeses manufactured from sixteen batches of milk on eight dairy farms scattered over the Appellation d' Origine Protégée (AOP) region were qualitatively and quantitatively evaluated microbiologically at various ripening times. Viable counts were performed after inoculation on appropriate selective media for aerobic mesophiles and proteolytic and lipolytic microflora, as well as lactococci, lactobacilli, species of Enterobacteriaceae, lactic streptococci, staphylococci, and yeasts. Members of the Enterobacteriaceae and lactic acid bacteria were the predominant microbial groups on all dairy farms throughout maturation; the latter are probably the microbial group responsible for most proteolytic and lipolytic breakdown in Serra da Estrela cheese. The microbial groups whose numbers were most affected by dairy-to-dairy variation were species of Enterobacteriaceae staphylococci, and enterococci, which are the most critical groups in terms of health hazards. It is therefore suggested that tighter control should be implemented at the level of choice of raw materials, in milk-handling practices, and in general throughout the manufacturing process in attempts to standardize production and consistently reduce microbiological risks (even though the distinctiveness of a few final organoleptic characteristics may somehow be reduced.
RAPD and SCAR markers as potential tools for detection of milk origin in dairy products: Adulterant sheep breeds in Serra da Estrela cheese production.

PubMed

Cunha, Joana T; Ribeiro, Tânia I B; Rocha, João B; Nunes, João; Teixeira, José A; Domingues, Lucília

2016-11-15

Serra da Estrela Protected Designation of Origin (PDO) cheese is the most famous Portuguese cheese and has a high commercial value. However, the adulteration of production with cheaper/lower-quality milks from non-autochthones ovine breeds compromises the quality of the final product and undervalues the original PDO cheese. A Randomly Amplified Polymorphic DNA (RAPD) method was developed for efficient detection of adulterant breeds in milk mixtures used for fraudulent production of this cheese. Furthermore, Sequence Characterized Amplified Region (SCAR) markers were designed envisioning the detection of milk adulteration in processed dairy foods. The RAPD-SCAR technique is here described, for the first time, to be potentially useful for detection of milk origin in dairy products. In this sense, our findings will play an important role on the valorization of Serra da Estrela cheese, as well as on other high-quality dairy products prone to adulteration, contributing to the further development of the dairy industry. Copyright © 2016 Elsevier Ltd. All rights reserved.
The sandfly fauna (Diptera: Psychodidae: Phlebotominae) of the Parque Estadual da Serra da Tiririca, Rio de Janeiro, Brazil.

PubMed

Rodrigues, Andressa Alencastre Fuzari; Barbosa, Vanessa de Araújo; Andrade Filho, José Dilermando; Brazil, Reginaldo Peçanha

2013-11-01

Cutaneous leishmaniasis (CL) in the state of Rio de Janeiro is sporadic and can be characterised as a peridomestic transmission that occurs in modified natural environments. The aim of this work was to study the fauna and ecological characteristics of sandflies in an environmentally protected area (the State Park of Serra da Tiririca) within the remnants of the Atlantic Forest in the municipalities of Niterói and Maricá and their possible relationship with leishmaniasis. Captures were performed using light traps during the night once a month for one year in both sylvatic environments and areas surrounding homes near the park. A total of 1,037 sandflies were captured, belonging to nine genera and 12 species: Evandromyia tupynambai (34.1%), Migonemyia migonei (20.6%), Brumptomyia cunhai (13.8%), Micropygomyia schreiberi (9.7%), Psathyromyia lanei (6.5%), Brumptomyia nitzulescui (5.7%), Evandromyia edwardsi (5.4%), Nyssomyia intermedia (2.8%), Evandromyia cortelezzii (0.6%), Pintomyia bianchigalatiae (0.5%), Lutzomyia longipalpis (0.2%) and Sciopemyia microps (0.1%). Both Mg. migonei and Ny. intermedia may be acting as vectors of CL in this area.
Weathering phases recorded by gnammas developed since last glaciation at Serra da Estrela, Portugal

NASA Astrophysics Data System (ADS)

Domínguez-Villar, David; Razola, Laura; Carrasco, Rosa M.; Jennings, Carrie E.; Pedraza, Javier

2009-09-01

The morphometrical analysis of gnammas (weathering pits) in granite landscapes has been used to establish the relative chronology of recent erosive surfaces and to provide the weathering history in a region. To test the validity of gnammas as relative chronometer indicators, and the reliability of the obtained weathering record, two sites have been studied in Serra da Estrela, Portugal. The first site is within the limits of the glacier that existed in these mountains during the last glaciation, whereas the second site is located in an unglaciated sector of the mountains, which preserves a longer record of weathering in the bedrock surface. The number of gnamma weathering phases recorded in the latter site (8) is larger than those from the former (6). Correlation between both measurement stations based on morphometrical criteria is excellent for the younger six weathering phases (1 to 6). Consequently, the parameter used for relative chronology ( δ-value) has been verified to be age dependent, although absolute values are modulated by microclimate due to altitude variations. The weathering record was essentially duplicated once the surfaces at both sites were exposed, demonstrating the reliability of gnamma evolution as a post-glacial environmental indicator for the region.
The (serra da) Estrela Aspiring Geopark (Portugal): preserving geoheritage, while promoting science and its links to local communities

NASA Astrophysics Data System (ADS)

Gomes, Hugo; Fernandes, Magda; Castro, Emanuel; Vieira, Gonçalo

2017-04-01

The serra da Estrela (1,993 m asl) is the highest mountain range in mainland Portugal. Bounded by two main fault scarps, a granite massif occupies the central area forming a summit plateau between ci. 1,500 and 2,000 m. To the north and south, schists and greywackes dominate the landscape, also with granite presence. During the Last Glacial a plateau ice-field and five radiating valley glaciers occupied the highest parts of the mountain with an estimated equilibrium line altitude at 1,650 m asl. The plateau style of the glaciation and the Equilibrium Line Altitude just below the plateau edge made the Estrela very sensitive to climate fluctuations, having resulted in several terminal moraine complexes that reveal several glacial stages. The central plateau area shows widespread glacial erosion features and an almost complete stripping of the Cenozoic weathering mantle. The non-glaciated plateaus show a rich landscape dominated by granite weathering landforms. The remarkable glacial landscape of the serra da Estrela when considering its setting in SW Europe, together with other significant geoheritage such as periglacial, weathering and mass wasting phenomena, tectonic, petrological and hydrogeological features, are at the core of Estrela's application to become a UNESCO Global Geopark. But the framework of the application encompasses both the natural and the human landscape, involving nine municipalities in the wider Estrela range, whose population bears an Estrelean signature in its roots, traditions, culture and economy. The Estrela Aspiring Geopark builds on a high value geoheritage closely bonded with biodiversity and the local communities, and its strategy aims at conservation and promoting regional development in an interdisciplinary approach committed UNESCO's principles. This presentation is a brief overview of the Estrela geoheritage, with a focus on the strategy for the implementation and management of the Geopark, emphasising on the science-support plan
Geodiversity, Geoturism and Geoconservation: Trails in Serra da Bocaina National Park, Rio de Janeiro State, Brazil.

NASA Astrophysics Data System (ADS)

Santos Filho, Raphael; Guerra, Antonio; Fullen, Michael; do Carmo Jorge, Maria

2015-04-01

The human being has always been concerned with the preservation of memory, of cultural heritage. Only now he started to protect its natural heritage and the immediate environment. It is time to learn how to protect the Earth's past and, through this protection and learn to know it. This memory comes before the human memory. It is a new asset: the geological heritage, a book written long before our appearance on the Planet (...)"(IPHAN, 2014). Since the XXth century, Brazilian geographers (GUERRA, 1980; AB'SABER, 2003 and others) dedicated to carry out research on the relationship of geographical knowledge between the environment and society. On the other hand, Brazil is a signatory of the Convention for the Protection of the World Heritage Cultural and Natural (UNESCO, 1972), where the nations recognize to keep under their responsibility the conservation, to the rest of humanity and future generations, goods of exceptional value situated within its territorial limits, considered as World Heritage. Under this perspective, it is proposed here a survey on the environmental impacts, resulting from the human activities that directly or indirectly affect the health, safety and welfare of the population; social and economic activities; the biota; the aesthetic and sanitary conditions of the environment; the quality of the environment (CONAMA Resolution 001/86) - and resulting geotourism practiced on trails - paths for pedestrians, cyclists and animals, existing in the protected area of the Serra da Bocaina National Park, in Rio de Janeiro State, such as unplanned use, erosive features, presence of litter, graffiti and burned, degraded areas on the trails indicating the need for recovery (drainage, etc.). This survey is based on research work of the environmental degradation and analysis undertaken by the Laboratory of Environmental Geomorphology and Soils Degradation (LAGESOLOS / UFRJ) in the area, in order to contribute to the geoconservation, so that the encountered
Endemic and threatened tetrapods in the restingas of the biodiversity corridors of Serra do Mar and of the Central da Mata Atlântica in eastern Brazil.

PubMed

Rocha, C F D; Van Sluys, M; Bergallo, H G; Alves, M A S

2005-02-01

Biodiversity corridors comprise a mosaic of land uses connecting fragments of natural forest across a landscape. Two such corridors have been established along the eastern coast of Brazil: the Serra do Mar and the Central da Mata Atlântica corridors, along which most of the coastal plains are restinga areas. In this study, we analyze the present status of the endemic and endangered terrestrial vertebrates of both corridors. We sampled 10 restingas in both corridors, recording species of amphibians, reptiles, birds, and mammals. Some restingas harbor a relatively large number of endemic species,and two main regions of endemism can be identified along the restingas of both corridors: the coastal restingas from northern Espirito Santo State to southern Bahia State (between Linhares, ES, and Tarancoso, BA), and the coastal region between the restingas of Maricá and Jurubatiba, Rio de Janeiro State. Six species of terrestrial vertebrates considered threatened with extinction are found in the restingas of Serra do Mar and Central da Mata Atlântica biodiversity corridors (Liolaemus lutzae, Formicivora littoralis, Mimus gilvus, Schistochlamys melanopis, and Trinomys eliasi). The region located between the restinga of Maricá and that of Jurubatiba is of special relevance for the conservation of vertebrate species of the restingas of the corridors because a considerable number of threatened species of terrestrial vertebrates are found there. We strongly recommend efforts to develop checklists of threatened faunas for the States of Espirito Santo and Bahia.
Novel bisabolane derivative from "arnica-da-serra" (Vernonieae: Asteraceae) reduces pro-nociceptive cytokines levels in LPS-stimulated rat macrophages.

PubMed

Petinatti Pavarini, Daniel; Nogueira, Elídia Fernandes; Callejon, Daniel Roberto; Soares, Denis Melo; de Souza, Glória Emilia Petto; Cunha, Fernando de Queiroz; Lopes, João L C; Lopes, Norberto Peporine

2013-07-30

Hydro alcoholic leaves extracts (HALE) of Lychnophora ericoides Mart. ("false arnica" or "arnica-da-serra") had been popularly used against pain and inflammatory process. The present work aimed to look for possible active volatile compounds that could be found in HALE of Lychnophora ericoides among the non volatile anti-inflammatory and analgesic compounds previously reported. Harvests were performed during the end of the wet summer season (April) when scented branches were instantly collected and frozen. HALE's were simulated at the lab by following the procedures lectured by the locals. Mass Spectrometry experiments suggested structural information when using both EI-MS and ESI-MS/MS. After isolation through classical thin layer chromatography (TLC) procedures, the NMR experiments and signals assignments were carried out. The effects on the cytokines or nitric oxide (NO) production were assessed at in vitro assays that had monitored the levels of these substances on the supernatant of LPS-stimulated macrophage primary cell culture. The major metabolite from HALE was isolated from the essential oil and the major compound had its molecular formulae established by Mass Spectrometry (High Resolution) and its structure by NMR. Literature-based investigation enables us to define the structure of the new metabolite as 6-methyl-2-(4-methylcyclohex-4-enyl-2-acetyloxy) hept-5-en-2-ol and its name as orto-acetoxy-bisabolol. In vitro assay of interleukins release inhibition was carried out using rat peritoneal macrophages cultures. IL-1β and TNF-α levels were significantly reduced when cells were previously treated with low doses of orto-acetoxy-bisabolol, but neither IL-6 nor NO levels have their levels reduced. Results suggest that ethnical knowledge of anti-inflammatory and analgesic effects of the "arnica-da-serra" HALE may be associated to the orto-acetoxy-bisabolol ability on synthesis inhibition of the key inflammatory/hypernociceptive mediators. Phytochemical
Multiseasonal and geobotanical approach in remote detection of greisenization areas in the Serra da Pedra Branca Granite, Goias State, Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Almeidafilho, R.

1983-01-01

Multiseasonal analysis of LANDSAT multispectral images in CCT format permitted the mapping of lithologic facies in the Pedra Branca Granite, using geobotanical associations, which occur in the form of variations in the density of cerrado vegetation, as well as the predominance of certain distinctive vegetation species. Dry season images did not show very good results in lithological differentiation due to anomalous illumination conditions related to the low solar elevation and the homogeneity in the vegetation cover, specially the grasses that become dry during this season. Rainy season image, on the other hand, allowed the separation of the lithological types, a fact that can be attributed to a greater differentiation among the geobotanical associations. As a result of this study, the muscovite-granite facies with greisenization zones, which are lithological indicators of important tin mineralization within the Serra da Pedra Branca Granite, were mapped. This methodology can be sucessfully applied to similar known granite bodies elsewhere in the Tin Province of Goias.
Multitemporal and geobotanical approach in the remote detection of Greisenization areas in the Serra da Pedra Branca Granite, Goias State, Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Filho, R. A.

1982-01-01

A multiseasonal analysis of LANDSAT multispectral images in CCT format permitted the mapping of lithologic facies in the Pedra Branca Granite, using geobotanical associations, which occur in the form of variations in the density of the cerrado vegetation, as well as the predominance of certain distinct vegetation species. Dry season images did not show very good results in lithological differentiation due to anomalous illumination conditions related to the low solar elevation and the homogeneity in the vegetation cover, specially the grass that becomes dry during this season. Rainy season images, on the other hand, allowed the separation of the lithological types, a fact that can be attributed to a greater differentiation among the geobotanical associations. The muscovite-granite facies with greisenization zones within the Serra da Pedra Branca were mapped. This methodology can be successfully applied to similar known granite bodies elsewhere in the Tin Province of Goias.
Characteristical analysis of high school astronomy's learning in Rio Grande da Serra, Ribeirão Pires and Mauá

NASA Astrophysics Data System (ADS)

Faria, R. Z.; Voelzke, M. R.

Even though astronomy is one of the oldest science that contributes to the human and thecnological development, its concepts are rarely taught for students of high school. The present research discusses two aspects related to the teaching of astronomy. The first aspect is to know whether astronomy is discussed in high school classes and the second on is related to the way how teachers approach astronomy. In order to find out this, a questionnaire was applied for the teachers who teach physics classes and work in state schools in Rio Grande da Serra, Ribeirão Pires and Mauá in São Paulo. From 66.2% of the teachers who answered to the questionnaire in the three chosen cities, 57.4% did not discuss any subject about astronomy, 89.4% did not use any kind of computer program, 70.2% did not use laboratory, 83.0% never took the students for museums or observatories and 38.3% did not indicate any kind magazine or book about astronomy. Although the majority of the teachers admit that the astronomy content influences the education of the student, they do not include the subject in their planning.

Characteristical Analysis of High School Astronomy's Teaching in Rio Grande da Serra, Ribeirão Pires and Mauá

NASA Astrophysics Data System (ADS)

Faria, R. Z.

2008-08-01

Considering that Astronomy is one of the oldest science that contributes to the human and technological development, its concepts are rarely taught for students of High School. The present research argues two aspects related to the method of teaching Astronomy. The first aspect is if it has been discussed in the classes by teachers of High School, and the second one treats of the way it has been taught by these teachers. In order to find out this, a questionnaire was applied for the teachers who teach Physics classes and work in state schools in Rio Grande da Serra, Ribeirão Pires and Mauá in São Paulo. From 66.2% of the teachers who answered to the questionnaire in the three cities researched, 57.4% did not give any subject about Astronomy, 89.4% did not use any kind of computer program, 70.2% did not use laboratory, 83.0% never took the students for museums or observatories and 38.3% did not indicate any kind of magazine or book about Astronomy. Although the majority of the teachers admit that the Astronomy influence the education of the student, they do not include the subject in their planning.
Background Noise of the Aldeia da Serra Region (Portugal) from a temporary broad band network

NASA Astrophysics Data System (ADS)

Wachilala, Piedade; Borges, José; Caldeira, Bento; Bezzeghoud, Mourad

2017-04-01

In this study, we analyse seismic background noise to assess the effect of noise based on the detectability of a temporary network constituted by DOCTAR (Deep Ocean Test Array), who have been deployed in a period between 2011 and 2012 in Portugal mainland, and the Évora permanent seismic station. This network is constituted by 14 digital broadband stations (14 CMG-3ESP and one STS2 sensors) with a flat response between the 60 sec to 50 Hz, 24-bit and 120s to 60Hz respectively. The temporary network was operated in continuous recording mode (three-components) in a region located in the north of the region of Évora, within a radius of about 30 km around the village of Aldeia da Serra, region in which there is an important seismic activity in the context of Portugal mainland. We calculated power spectral densities of background noise for each station/component and compare them with high-noise model and low-noise model of Peterson (1993). We consider different for day and night local and for different periods of the year. Power spectral density estimates show moderate noise levels with all stations falling within the high and low bounds of Peterson (1993). Considering the results of the noise, we estimate the detection limit of each station and consequently the detectability of the network. From this information and taking in attention the events recorded during the period of DOCTAR operation we analyse the improvement promoted by this temporary network regarding the existent seismic networks to the local seismicity study. This work was partially supported by COMPETE 2020 program (POCI-01-0145-FEDER-007690 project). We acknowledge GFZ Potsdam for providing part of the data used in this study.
The influence of fire on the assemblage structure of foraging birds in grasslands of the Serra da Canastra National Park, Brazil.

PubMed

Reis, Matheus G; Fieker, Carolline Z; Dias, Manoel M

2016-05-13

Grasslands are the most threatened physiognomies of the Cerrado biome (Brazilian savanna), a biodiversity hotspot with conservation as a priority. The Serra da Canastra National Park protects the most important remnants of the Cerrado's southern grasslands, which are under strong anthropogenic pressure. The present study describes the structure of bird assemblages that directly use food resources in burned areas, comparing areas affected by natural fire to the areas where controlled fires were set (a management strategy to combat arson). The tested null hypothesis was that different bird assemblages are structured in a similar manner, regardless of the post-fire period or assessed area. Between December/2012 and January/2015, 92 species were recorded foraging in the study areas. The results indicate that both types of burnings triggered profound and immediate changes in bird assemblages, increasing the number of species and individuals. Natural fires exhibited a more significant influence on the structure (diversity and dominance) than prescribed burnings. Nevertheless, all the differences were no longer noticeable after a relatively short time interval of 2-3 months after prescribed burnings and 3-4 after natural fires. The findings may help the understanding of prescribed burnings as a management strategy for bird conservation in grasslands.
76 FR 10936 - Culturally Significant Objects Imported for Exhibition Determinations: “Richard Serra Drawing: A...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-28

... DEPARTMENT OF STATE [Public Notice: 7348] Culturally Significant Objects Imported for Exhibition Determinations: ``Richard Serra Drawing: A Retrospective'' SUMMARY: Notice is hereby given of the following... objects to be included in the exhibition ``Richard Serra Drawing: A Retrospective,'' imported from abroad...
A Influência da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos

NASA Astrophysics Data System (ADS)

da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

2006-08-01

O universo em que vivemos possui segredos jamais imaginados pelo homem, fruto da pequena proporção que ocupamos diante de um cosmos infinito. A astronomia funciona como um instrumento que sacia a sede humana em desvendar esses segredos, estudando as galáxias, quasares, pulsares além da existência de todos os elementos que preenchem o espaço cósmico, o vácuo, não mais vazio como se pensou em outros tempos. A mídia explora esse campo de forma mística e também científica. A difusão adequada e dentro dos padrões educacionais vigentes, de conceitos astronômicos, se faz necessária, devido sua presença nos conteúdos escolares, centros de ciência e na mídia, de modo geral. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros introduziu conceitos astronômicos desde a pré-escola até o Ensino Médio. Num estudo realizado com 1.032 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um questionário que abordava conheciment os básicos em astronomia, como estes foram adquiridos e qual era a infra-estrutura oferecida pela escola: para 66,2% dos entrevistados o professor já fez alguma apresentação a respeito de astronomia. O presente estudo revelou também que 44,5% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 28,1% através da televisão e 27,4% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio na forma em que os alunos obtiveram seus conhecimentos astronômicos, a mídia ainda explora e muitas vezes desperta o interesse pela astronomia com assuntos que não fazem parte de nosso cotidiano como, por exemplo, o homem na Lua, os projetos espaciais e a primeira viagem de um astronauta brasileiro no espaço. Porém, em certos casos, a mídia pode promover conhecimentos incompletos ou mesmo equivocados sobre os conceitos que envolvam
Parasites of domestic and wild canids in the region of Serra do Cipó National Park, Brazil.

PubMed

Santos, Juliana Lúcia Costa; Magalhães, Noele Borges; Dos Santos, Hudson Andrade; Ribeiro, Raul Rio; Guimarães, Marcos Pezzi

2012-01-01

Over recent decades, diseases have been shown to be important causes of extinctions among wild species. Greater emphasis has been given to diseases transmitted by domestic animals, which have been increasing in numbers in natural areas, along with human populations. This study had the aim of investigating the presence of intestinal helminths in wild canids (maned wolf, Chrysocyon brachyurus, and crab-eating fox, Cerdocyon thous) in the Serra do Cipó National Park (43-44º W and 19-20º S) and endo and ectoparasites of domestic dogs in the Morro da Pedreira Environmental Protection Area (an area surrounding the National Park). The Serra do Cipó is located in the state of Minas Gerais, Brazil. Among the enteroparasites found in domestic and wild canids, the following taxons were identified: Ancylostomidae, Trichuridae, Toxocara sp., Spirocerca sp., Physaloptera sp., Strongyloides sp., Cestoda, Dipylidium caninum, Diphyllobothriidae, Hymenolepidae, Anoplocephalidae, Trematoda, Acanthocephala and Isospora sp. Domestic dogs were positive for leishmaniasis and Babesia canis in serological tests. Among the ectoparasites, Rhipicephalus sanguineus, Amblyomma cajennense and Ctenocephalides felis felis were observed in domestic dogs. Variations in the chaetotaxy of the meta-episternum and posterior tibia were observed in some specimens of C. felis felis.
Identification of a 170-kDa protein associated with the vacuolar Na+/H+ antiport of Beta vulgaris.

PubMed Central

Barkla, B J; Blumwald, E

1991-01-01

The effect of the addition of amiloride to the growth medium was tested on the Na+/H+ antiport activity of tonoplast vesicles isolated from sugar beet (beta vulgaris L.) cell suspensions. Cells grown in the presence of NaCl and amiloride displayed an increased antiport activity. Analysis of the kinetic data showed that while the affinity of the antiport for Na+ ions did not change, the maximal velocity of the Na+/H+ exchange increased markedly. These results suggest the addition of more antiport molecules to the tonoplast and/or an increase in the turnover rate of the Na+/H+ exchange. The increase in activity of the antiport by the presence of amiloride was correlated with the enhanced synthesis of a tonoplast 170-kDa polypeptide. The increased synthesis of this polypeptide was detected not only upon exposure of the cells to amiloride but also when the cells were exposed to high NaCl concentrations. Polyclonal antibodies against the 170-kDa polypeptide almost completely inhibited the antiport activity. These results suggest the association of the 170-kDa polypeptide with the vacuolar Na+/H+ antiport. Images PMID:1662387
Identification of a 170-kDa protein associated with the vacuolar Na+/H+ antiport of Beta vulgaris.

PubMed

Barkla, B J; Blumwald, E

1991-12-15

The effect of the addition of amiloride to the growth medium was tested on the Na+/H+ antiport activity of tonoplast vesicles isolated from sugar beet (beta vulgaris L.) cell suspensions. Cells grown in the presence of NaCl and amiloride displayed an increased antiport activity. Analysis of the kinetic data showed that while the affinity of the antiport for Na+ ions did not change, the maximal velocity of the Na+/H+ exchange increased markedly. These results suggest the addition of more antiport molecules to the tonoplast and/or an increase in the turnover rate of the Na+/H+ exchange. The increase in activity of the antiport by the presence of amiloride was correlated with the enhanced synthesis of a tonoplast 170-kDa polypeptide. The increased synthesis of this polypeptide was detected not only upon exposure of the cells to amiloride but also when the cells were exposed to high NaCl concentrations. Polyclonal antibodies against the 170-kDa polypeptide almost completely inhibited the antiport activity. These results suggest the association of the 170-kDa polypeptide with the vacuolar Na+/H+ antiport.
The DaNa2.0 Knowledge Base Nanomaterials—An Important Measure Accompanying Nanomaterials Development

PubMed Central

Bohmer, Nils; Marquardt, Clarissa; Nau, Katja; Steinbach, Christoph

2018-01-01

Nanotechnology is closely related to the tailored manufacturing of nanomaterials for a huge variety of applications. However, such applications with newly developed materials are also a reason for concern. The DaNa2.0 project provides information and support for these issues on the web in condensed and easy-to-understand wording. Thus, a key challenge in the field of advanced materials safety research is access to correct and reliable studies and validated results. For nanomaterials, there is currently a continuously increasing amount of publications on toxicological issues, but criteria to evaluate the quality of these studies are necessary to use them e.g., for regulatory purposes. DaNa2.0 discusses scientific results regarding 26 nanomaterials based on actual literature that has been selected after careful evaluation following a literature criteria checklist. This checklist is publicly available, along with a selection of standardized operating protocols (SOPs) established by different projects. The spectrum of information is rounded off by further articles concerning basics or crosscutting topics in nanosafety research. This article is intended to give an overview on DaNa2.0 activities to support reliable toxicity testing and science communication alike. PMID:29596351
The influence of the area of the Serra da Mesa Hydroelectric Plant, State of Goiás, on the frequency and diversity of anophelines (Diptera: Culicidae): a study on the effect of a reservoir.

PubMed

Melandri, Vanessa; Alencar, Jerônimo; Guimarães, Anthony Érico

2015-01-01

Bioecological aspects of anophelines (Diptera: Culicidae) near areas under the direct influence of the hydroelectric plant reservoir of Serra da Mesa in Goiás, Brazil, were analyzed. Samples were collected at the surrounding dam area during the phases before and after reservoir impoundment. The influence of climatic and environmental factors on the occurrence of Anopheles darlingi, Anopheles albitarsis, Anopheles triannulatus, Anopheles oswaldoi and Anopheles evansae was assessed using Pearson's correlations with indicators for richness and diversity as well as the index of species abundance (ISA) and the standardized index of species abundance (SISA). The highest anopheline density occurred during the phase after filling the tank; however, no direct correlation with the climatic factors was observed during this stage. The reservoir formation determined the incidence of the anopheline species. An. darlingi was the predominant species (SISA = 1.00). The significant difference (p < 0.05) observed between the species incidence during the different reservoir phases demonstrates the environmental effect of the reservoir on anophelines.
Serra Pelada: the first Amazonian Meteorite fall is a Eucrite (basalt) from Asteroid 4-Vesta.

PubMed

Zucolotto, Maria Elizabeth; Tosi, Amanda A; Villaça, Caio V N; Moutinho, André L R; Andrade, Diana P P; Faulstich, Fabiano; Gomes, Angelo M S; Rios, Debora C; Rocha, Marcilio C

2018-01-01

Serra Pelada is the newest Brazilian eucrite and the first recovered fall from Amazonia (State of Pará, Brazil, June 29th 2017). In this paper, we report on its petrography, chemistry, mineralogy and its magnetic properties. Study of four thin sections reveals that the meteorite is brecciated, containing basaltic and gabbroic clasts, as well of recrystallized impact melt, embedded into a fine-medium grained matrix. Chemical analyses suggest that Serra Pelada is a monomict basaltic eucritic breccia, and that the meteorite is a normal member of the HED suite. Our results provide additional geological and compositional information on the lithological diversity of its parent body. The mineralogy of Serra Pelada consists basically of low-Ca pyroxene and high-Ca plagioclase with accessory minerals such as quartz, sulphide (troilite), chromite - ulvöspinel and ilmenite. These data are consistent with the meteorite being an eucrite, a basaltic achondrite and a member of the howardite-eucrite-diogenite (HED) clan of meteorites which most likely are from the crust asteroid 4 Vesta.
Relevant principal component analysis applied to the characterisation of Portuguese heather honey.

PubMed

Martins, Rui C; Lopes, Victor V; Valentão, Patrícia; Carvalho, João C M F; Isabel, Paulo; Amaral, Maria T; Batista, Maria T; Andrade, Paula B; Silva, Branca M

2008-01-01

The main purpose of this study was the characterisation of 'Serra da Lousã' heather honey by using novel statistical methodology, relevant principal component analysis, in order to assess the correlations between production year, locality and composition. Herein, we also report its chemical composition in terms of sugars, glycerol and ethanol, and physicochemical parameters. Sugars profiles from 'Serra da Lousã' heather and 'Terra Quente de Trás-os-Montes' lavender honeys were compared and allowed the discrimination: 'Serra da Lousã' honeys do not contain sucrose, generally exhibit lower contents of turanose, trehalose and maltose and higher contents of fructose and glucose. Different localities from 'Serra da Lousã' provided groups of samples with high and low glycerol contents. Glycerol and ethanol contents were revealed to be independent of the sugars profiles. These data and statistical models can be very useful in the comparison and detection of adulterations during the quality control analysis of 'Serra da Lousã' honey.
Age distribution of Serra Geral (Paraná) flood basalts, southern Brazil

USGS Publications Warehouse

Fodor, R.V.; McKee, E.H.; Roisenberg, A.

1989-01-01

We evaluated 193 K-Ar ages (10 newly determined) of basaltic and differentiated rocks of the Serra Geral (Paraná) flood-basalt province for indications of magmatism occurring systematically with progressive rifting and complete separation ( ≈130-105 Ma) of South America from Africa. The K-Ar ages represent basalt emplacement between 35° and 19°S covering about 1,200,000 km2. We note that volcanism appears ubiquitous across the province between about 140 and 115 Ma, and that there are no significant age differences within that relate directly to progressive south-to-north tectonism. On the other hand, the oldest samples, about 140–160 Ma, are among those nearest the Brazil coastline (rift margin), perhaps suggesting migration of activity away from the rift with time. Studies of other flood-basalt provinces now indicate short (<3 m.y.) eruption periods, thereby pointing to the need for re-examination of Serra Geral ages by 40Ar-39Ar incremental heating techniques.
The Brazilian Malaria Vector Anopheles (Kerteszia) Cruzii: Life Stages and Biology (Diptera: Culicidae)

DTIC Science & Technology

1991-11-01

Mosquitos no litoral paranaense. I - Idade fisioldgica de no Parque National da Serra dos Orgaos, Anopheles cruzii (Diptera, Culicidae). Arq. Estado do...no Parque National da Peryassii, A.G. 1908. OS culicideos do Brazil. Serra dos Grgaos, Estado do Rio de Janeiro, Inst. de Manguinhos, Rio de Janeiro...Kerteszia no litoral Guimar%es, A.E. and V.N.M. Victoria. 1986. do estado de Santa Catarina. Rev. Bras. Mosquitos no Parque National da Serra dos
Pyroxenes in Serra de Mage - Cooling history in comparison with Moama and Moore County

NASA Technical Reports Server (NTRS)

Harlow, G. E.; Prinz, M.; Nehru, C. E.; Taylor, G. J.; Keil, K.

1979-01-01

Thin sections and single grains of pyroxenes from the Serra de Mage feldspar cumulate eucrites were studied by X-ray crystallography, electron microprobe and optical techniques. It was concluded that the pyroxene crystallized as pigeonite. On cooling augite was exsolved along (001) and inverted to hypersthene, with exsolution of (100) augite from hypersthene during continued slow cooling. The estimated original bulk composition of the pigeonite pyroxene is Wo10En51Fs39. The compositional data, textural relations, and existence of P2 sub 1 ca hypersthene suggest very low cooling (about 0.0004 deg C/year) below 800 deg. The Serra de Mage augite lamellae were found to be as thick or thicker than those of Moore County and Moama meteorites.
Impacts of the Conservation Education Program in Serra Malagueta Natural Park, Cape Verde

ERIC Educational Resources Information Center

Burnett, Edmund; Sills, Erin; Peterson, M. Nils; DePerno, Christopher

2016-01-01

Environmental and conservation education programs are commonly offered in the rapidly expanding network of protected areas in developing countries. There have been few evaluations of these programs and their impacts on participants. At Serra Malagueta Natural Park in Cape Verde, we assessed changes in environmental knowledge, opinions, and…
Fluid inclusions in calcite filled opening fractures of the Serra Alta Formation reveal paleotemperatures and composition of diagenetic fluids percolating Permian shales of the Paraná Basin

NASA Astrophysics Data System (ADS)

Teixeira, C. A. S.; Sawakuchi, A. O.; Bello, R. M. S.; Nomura, S. F.; Bertassoli, D. J.; Chamani, M. A. C.

2018-07-01

The thermal and diagenetic evolution of shale units has received renewed focus because of their emergence as unconventional hydrocarbon reservoirs. The Serra Alta Formation (SAF) is a Permian shale unit of the Paraná Basin, which is the largest South American cratonic basin. The SAF stands out as a pathway for aqueous fluids and hydrocarbon migration from the Irati organic-rich shales to the Pirambóia fluvial-eolian sandstone reservoirs. Vertical NNW and NNE opening fractures would be the main pathways for the migration of buried pore waters and aqueous fluids, besides the input of meteoric water. These fractures would be associated to the reactivation of basement discontinuities such as the Jacutinga (NE) and Guapiara (NW) faults. Thus, vertical NNE and NNW associated fractures would represent the main pathways for fluid migration in the studied area. The vertical calcite filled opening fractures from SAF record moderately low salinity (0-4.5 wt % of NaCl eq.) aqueous fluids, suggesting the input of meteoric water in the buried fracture system. Eutectic melting temperatures at -52±5 °C indicate an H2O + NaCl + CaCl2 system with CaCl2 or MgCl2 in solution. Homogenization temperatures recorded in fluid inclusion assemblages (FIAs) of calcite filled opening fractures indicate that the SAF in the studied area reached temperatures above 200 °C, suitable for generation of gaseous hydrocarbons. The recorded paleotemperatures point to a thermal peak associated with Serra Geral volcanic event during the Early Cretaceous, with the thermal effect of volcanic rock cap possibly overcoming the effect of intrusive igneous bodies. The detection of methane in SAF shale pores indicates conditions for hydrocarbon generation. However, additionally studies are necessary to confirm the thermogenic and/or biogenic origin of the methane within the SAF.
Hematology and blood chemistry parameters differ in free-ranging maned wolves (Chrysocyon brachyurus) living in the Serra da Canastra National Park versus adjacent farmlands, Brazil.

PubMed

May-Júnior, J A; Songsasen, N; Azevedo, F C; Santos, J P; Paula, R C; Rodrigues, F H G; Rodden, M D; Wildt, D E; Morato, R G

2009-01-01

There has been growing interest in the specific impacts of anthropogenic factors on the health of wildlife. This study examined hematology and serum chemistry status of a prominent carnivore, the maned wolf (Chrysocyon brachyurus), living in, on the boundaries to, or on adjacent farmlands to the Serra da Canastra National Park, Brazil. Twenty-eighty wolves were captured, and values were compared 1) between subadults (n=8 animals) and adults (n=20 animals), 2) males (n=12 animals) and females (n=16 animals), and 3) among wolves living inside the park (n=11), near the park border (n=11 animals), and in neighboring farming areas (n=6 animals). Age, gender, and wolf locations influenced (P<0.05) hematology and serum biochemistry values. Specifically, adults had lower (P<0.05) circulating phosphorus than subadults. Males had lower (P<0.05) serum glucose, creatinine phosphokinase, and cholesterol and higher (P<0.05) potassium than females. Erythrocyte count and serum cholinesterase were lower (P<0.05) in wolves living within the park compared with near the park border or on farmlands. Mean corpuscular volume was lower (P<0.05) in wolves living near the park border than those ranging within the park and on farmlands. Aspartate transaminase and chloride were higher (P<0.05) in wolves living inside the park compared with those ranging near the park border. Creatinine phosphokinase was lower (P<0.05) in wolves living on farmland compared with the other two locations. These results clearly reveal a relationship between age and gender on hematology and serum biochemistry values in free-living maned wolves. More importantly, certain traits indicative of health are potentially compromised in wolves living in areas under anthropogenic pressure. These data lay a foundation for examining the influence of farming and local domestic species on disease susceptibility and fitness in the maned wolf.
Amphibians of Serra Bonita, southern Bahia: a new hotpoint within Brazil's Atlantic Forest hotspot.

PubMed

Dias, Iuri Ribeiro; Medeiros, Tadeu Teixeira; Vila Nova, Marcos Ferreira; Solé, Mirco

2014-01-01

We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km(2) with steep altitudinal gradients (200-950 m a.s.l.) located in the municipalities of Camacan and Pau-Brasil, southern Bahia State, Brazil. Data were obtained at 38 sampling sites (including ponds and transects within the forest and in streams), through active and visual and acoustic searches, pitfall traps, and opportunistic encounters. We recorded 80 amphibian species distributed in 15 families: Aromobatidae (1), Brachycephalidae (3), Bufonidae (4), Centrolenidae (2), Ceratophryidae (1), Craugastoridae (7), Eleutherodactylidae (2), Hemiphractidae (2), Hylidae (42), Hylodidae (1), Leptodactylidae (7), Microhylidae (3), Siphonopidae (1), Odontophrynidae (3) and Pipidae (1). Species richness was positively correlated with monthly rainfall. Near 36% of the species were found in strictly forest environments, 15% are endemic to Bahia State and 77.2% are endemic to the Atlantic Forest biome. The large species diversity of this small area, the high degree of endemism and the taxonomic and biogeographic significance turn the Serra Bonita mountain into a hotpoint for amphibians within Brazil's Atlantic Forest hotspot.
Larva and pupa of Ctesias (s. str.) serra (Fabricius, 1792) with remarks on biology and economic importance, and larval comparison of co-occurring genera (Coleoptera, Dermestidae).

PubMed

Kadej, Marcin

2018-01-01

Updated descriptions of the last larval instar (based on the larvae and exuviae) and first detailed description of the pupa of Ctesias (s. str.) serra (Fabricius, 1792) (Coleoptera: Dermestidae) are presented. Several morphological characters of C. serra larvae are documented: antenna, epipharynx, mandible, maxilla, ligula, labial palpi, spicisetae, hastisetae, terga, frons, foreleg, and condition of the antecostal suture. The paper is fully illustrated and includes some important additions to extend notes for this species available in the references. Summarised data about biology, economic importance, and distribution of C. serra are also provided. The comparison of larval characteristics for some of the genera of Dermestidae co-occurring with Ctesias is presented. A key for identification of these genera is also provided.

The kinematic evolution of the Serra Central Salient, Eastern Brazil: A Neoproterozoic progressive arc in northern Espinhaço fold-thrust belt

NASA Astrophysics Data System (ADS)

Bersan, Samuel Moreira; Danderfer, André; Lagoeiro, Leonardo; Costa, Alice Fernanda de Oliveira

2017-12-01

Convex-to-the-foreland map-view curves are common features in fold-thrust belts around cratonic areas. These features are easily identifiable in belts composed of supracrustal rocks but have been rarely described in rocks from relatively deeper crustal levels where plastic deformation mechanisms stand out. Several local salients have been described in Neoproterozoic marginal fold-thrust belts around the São Francisco craton. In the northern part of the Espinhaço fold-thrust belt, which borders the eastern portion of the São Francisco craton, both Archean-Paleoproterozoic basement rocks and Proterozoic cover rocks are involved in the so-called Serra Central salient. A combination of conventional structural analysis and microstructural and paleostress studies were conducted to characterize the kinematic and the overall architecture and processes involved in the generation of this salient. The results allowed us to determine that the deformation along the Serra Central salient occur under low-grade metamorphic conditions and was related to a gently oblique convergence with westward mass transport that developed in a confined flow, controlled by two transverse bounding shear zones. We propose that the Serra Central salient nucleates as a basin-controlled primary arc that evolves to a progressive arc with secondary vertical axis rotation. This secondary rotation, well-illustrated by the presence of two almost orthogonal families of folds, was dominantly controlled by buttress effect exert by a basement high located in the foreland of the Serra Central salient.
Amphibians of Serra Bonita, southern Bahia: a new hotpoint within Brazil’s Atlantic Forest hotspot

PubMed Central

Dias, Iuri Ribeiro; Medeiros, Tadeu Teixeira; Vila Nova, Marcos Ferreira; Solé, Mirco

2014-01-01

Abstract We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km2 with steep altitudinal gradients (200–950 m a.s.l.) located in the municipalities of Camacan and Pau-Brasil, southern Bahia State, Brazil. Data were obtained at 38 sampling sites (including ponds and transects within the forest and in streams), through active and visual and acoustic searches, pitfall traps, and opportunistic encounters. We recorded 80 amphibian species distributed in 15 families: Aromobatidae (1), Brachycephalidae (3), Bufonidae (4), Centrolenidae (2), Ceratophryidae (1), Craugastoridae (7), Eleutherodactylidae (2), Hemiphractidae (2), Hylidae (42), Hylodidae (1), Leptodactylidae (7), Microhylidae (3), Siphonopidae (1), Odontophrynidae (3) and Pipidae (1). Species richness was positively correlated with monthly rainfall. Near 36% of the species were found in strictly forest environments, 15% are endemic to Bahia State and 77.2% are endemic to the Atlantic Forest biome. The large species diversity of this small area, the high degree of endemism and the taxonomic and biogeographic significance turn the Serra Bonita mountain into a hotpoint for amphibians within Brazil’s Atlantic Forest hotspot. PMID:25408616
Qual o Papel da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos?

NASA Astrophysics Data System (ADS)

da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

2007-08-01

É amplamente reconhecido que as pessoas em geral têm grande fascínio e interesse pela Astronomia. Por outro lado, o conteúdo dessa área incluído no ensino formal está longe de ser abrangente e suficiente para suprir a demanda. Esse interesse permite aperfeiçoar a divulgação e o ensino não formal de Astronomia através da mídia aliando a adequação do conteúdo à expectativa das pessoas. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros tem introduzido Astronomia desde a pré-escola até o Ensino Médio. Num estudo realizado com 1180 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um formulário contendo questões que abordavam conhecimentos básicos em Astronomia, como foram adquiridos tais conhecimentos e à infra-estrutura da escola. Para 66,1% dos entrevistados o professor já fez alguma apresentação a respeito de Astronomia. O presente estudo revelou também que 54,4% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 18,4% através da televisão e 27,1% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, livros didáticos, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio no meio em que os alunos obtiveram seus conhecimentos astronômicos, a mídia busca não somente sua difusão, mas a disponibilização desse conhecimento de maneira correta, que às vezes, não é atingido, apresentando conceitos sem fundamentação e incorretos. Por outro lado, no dia-a-dia escolar, é comum encontrar professores que vêm para as aulas com concepções prévias, que podem diferir substancialmente das idéias a serem ensinadas, dificultando o aprendizado de futuros conceitos científicos. Uma avaliação criteriosa, avaliando as dificuldades dos professores em determinar o sentido correto dos conceitos e observando a metodologia que utilizam no ensino, poderá proporcionar uma melhor
Spatial and seasonal characteristics of cold-air pools in the upper Zêzere valley (Serra da Estrela, Portugal)

NASA Astrophysics Data System (ADS)

Mora, Carla

2010-05-01

Occurrence, formation, spatial patterns and intensity of cold air pools/lakes were studied in the Serra da Estrela (40° 20'N 7° 35'W, 1993m, Central Portugal) from January to December 2000. Data was collected using a network of air temperature dataloggers installed at different topographic positions (interfluves, valley floors and slopes) recording at 2-h intervals. A k-means classification was applied to the dataset of instantaneous air temperatures, and 3 types of thermal patterns were identified. Type 1 (66% cases) shows events with decreasing air temperatures with altitude. Type 2 (27% cases) shows accumulation of cold air in the valleys with higher valley floors showing the lowest temperatures. Type 3 (7% cases) show accumulation of cold air, but with lowest air temperatures in the valleys at lower altitudes. Causal factors for the occurrence of the patterns were studied by applying discriminant analysis on meteorological and topographical variables. Type 1 occurs under atmospheric instability conditions, while types 2 and 3 relate to atmospheric stability. Types 2 and 3 are controlled by seasonality and local insolation/shadowing effects. For the detailed study of cold air accumulations, two approaches were followed: the analysis of temperature differences between a station in a crest and a station in a glacial cirque floor; and, the analysis of 5-min interval temperature data along a transect in the Zêzere valley.The differences in air temperature between the glacier cirque floor (Covão Cimeiro, 1620m) and the crest (Cântaro Gordo, 1870m) were classified into 9 types of regime. Thermal inversions in the cirque were found in 6 types (48%). These are characterized in detail and the geographical and meteorological controlling factors are analyzed using one-way ANOVA and discriminant analysis. The 6 types show different daily regimes and inversion intensities, as well as a seasonal trend. The maximum inversion intensity was 9 °C, and the minimum
Checklist of butterflies (Insecta: Lepidoptera) from Serra do Intendente State Park - Minas Gerais, Brazil

PubMed Central

Nery, Izabella; Carvalho, Natalia

2014-01-01

Abstract In order to contribute to the butterflies’ biodiversity knowledge at Serra do Intendente State Park - Minas Gerais, a study based on collections using Van Someren-Rydon traps and active search was performed. In this study, a total of 395 butterflies were collected, of which 327 were identified to species or morphospecies. 263 specimens were collected by the traps and 64 were collected using entomological hand-nets; 43 genera and 60 species were collected and identified. PMID:25535482
A importância da poeira e ondas de Alfvén na estabilidade de nuvens moleculares anãs

NASA Astrophysics Data System (ADS)

Falceta-Gonçalves, D.; de Juli, M. C.; Jatenco-Pereira, V.

2003-08-01

Nuvens moleculares anãs se apresentam dinamicamente estáveis, embora possuam massas muito maiores que a massa de Jeans. Por este motivo, a estabilidade destes objetos não pode ser explicada considerando-se apenas a pressão térmica. Campos magnéticos, aproximadamente uniformes e de ~mG, exercem um termo extra de pressão que sustenta a nuvem, mas somente na direção perpendicular às linhas de campo. Para a direção paralela, ondas de Alfvén geradas por turbulências no meio, por exemplo, têm sido utilizadas. Estas, sendo supostamente fracamente amortecidas, poderiam sustentar a nuvem nesta direção. Entretanto, estes meios contêm grandes quantidades de poeira carregada eletricamente. Estes grãos de poeira possuem frequências cíclotron, que podem entrar em ressonância com as ondas. Neste trabalho calculamos os efeitos que o amortecimento cíclotron da poeira teriam na propagação da onda, e consequentemente na estabilidade da nuvem. Considerando um fluxo de ondas, com um dado espectro de frequências, e uma população de grãos de poeira, com distribuição de tamanho observada, foi possível mostrar que o amortecimento é eficiente em uma larga banda de frequências. Neste caso as ondas seriam rapidamente amortecidas gerando pequenas condensações de alta densidade, e não poderiam ser utilizadas para explicar a estabilidade de uma nuvem inteira. Desta forma, rotação e turbulência seriam candidatos alternativos para garantir a estabilidade destes objetos.
Avaliação da influência de alterações cardíacas na ultrassonografia vascular periférica de idosos

PubMed Central

Ribeiro, Alcides José Araújo; Ribeiro, Andréa Campos de Oliveira; Rodrigues, Márcia Marisia Maciel; Negreiros, Sandra de Barros Cobra; Nogueira, Ana Cláudia Cavalcante; Almeida, Osório Luís Rangel; Silva, José Carlos Quináglia e; de Paula, Ana Patrícia

2016-01-01

Resumo Contexto As cardiopatias podem causar alterações no formato das ondas da ultrassonografia vascular (UV) em vasos periféricos. Essas alterações, tipicamente bilaterais e sistêmicas, são pouco conhecidas e estudadas. Objetivo Avaliar as ondas periféricas da UV de pacientes idosos para identificar alterações decorrentes de cardiopatias. Métodos Foram estudados 183 pacientes idosos submetidos a UV periférica no ano de 2014. Resultados Foram avaliados 102 mulheres (55,7%) e 81 homens (44,3%) com idade entre 60 e 91 anos (média de 70,4±7,2 anos). Encontraram-se alterações pela UV em 84 pacientes (45,9%). Foram identificadas 138 alterações de oito dos 13 tipos descritos na literatura: arritmia, onda bisferiens de pico sistólico, baixa velocidade de pico sistólico, pulsatilidade em veias femorais, bradicardia, taquicardia, onda de pulso parvus tardus e onda de pulso alternans. Houve baixa concordância entre a presença e a não presença de alterações na UV e na avaliação cardiológica. Na análise específica das alterações, os exames tiveram uma concordância variável, que foi boa para o achado de taquicardia, moderada para arritmia e baixa para bradicardia. Não houve concordância entre a UV e os exames cardiológicos para as demais alterações. Conclusões É possível identificar determinadas alterações cardíacas em idosos por meio da análise do formato das ondas periféricas da UV. É importante reconhecer e relatar a presença dessas alterações, pela possibilidade de alertar para um diagnóstico ainda não identificado nesses pacientes. Entretanto, mais estudos são necessários para que seja definida a importância das alterações no formato das ondas Doppler periféricas no reconhecimento de cardiopatias. PMID:29930591
Relief evolution of the Continental Rift of Southeast Brazil revealed by in situ-produced 10Be concentrations in river-borne sediments

NASA Astrophysics Data System (ADS)

Salgado, André Augusto Rodrigues; Rezende, Eric de Andrade; Bourlès, Didier; Braucher, Régis; da Silva, Juliana Rodrigues; Garcia, Ricardo Alexandrino

2016-04-01

This study aims to quantify the denudation dynamics of the Brazilian passive margin along a segment of the Continental Rift of Southeast Brazil. The denudation rates of 30 basins that drain both horsts of the continental rift, including the mountain ranges of the Serra do Mar (seaside horst); and the Serra da Mantiqueira (continental horst); were derived from 10Be concentrations measured in sand-sized river sediment. The mean denudation rate ranges from 9.2 m Ma-1 on the plateau of the Serra do Mar to 37.1 m Ma-1 along the oceanic escarpment of the Serra do Mar. The seaward-facing scarps of both mountain ranges exhibit mean denudation rates that are approximately 1.5 times those of the inland-facing scarps. The escarpments of the horst nearer to the ocean (Serra do Mar) exhibit higher denudation rates (mean 30.2 m Ma-1) than the escarpments of the continental horst (Serra da Mantiqueira) (mean 16.5 m Ma-1). The parameters that impact these denudation rates include the catchment relief, the slope gradient, the rock and the climate. The incongruent combination of a mountainous landscape and moderate to low 10Be-based denudation rates averaging at ∼20 m Ma-1 suggests a reduction in intraplate tectonic activity beginning in the Middle Quaternary or earlier.
Efeitos do binarismo não resolvido na determinação da função de massa de aglomerados

NASA Astrophysics Data System (ADS)

Kerber, L. O.; Santiago, B. X.

2003-08-01

Através de simulações numéricas buscamos quantificar os efeitos que o binarismo não resolvido causa na determinação da função de massa (MF) de aglomerados estelares. Geramos diagramas cor-magnitude (CMDs) artificiais simulando uma população única, caracterizada por estrelas de mesma idade e composição quí mica, com uma fração de binárias não resolvidas e distribuição em massa das estrelas dada por uma MF do tipo lei de potência. A presença de pares de estrelas não resolvidos faz com que a MF obtida da função de luminosidade (LF) tenha a têndencia de ser mais plana do que a MF que gerou o CMD artificial. Propomos um tratamento de correção para tal efeito. Outro efeito relacionado diz respeito ao alargamento do CMD, que apresenta-se como um indicador do número total de estrelas no domí nio de baixas massas (m < 0.6M¤). Todos os resultados acima possuem uma forte dependência com os erros fotométricos e estão baseados na hipótese de que ambas estrelas do par não resolvido são sorteadas de uma mesma MF de forma independente. O objetivo final é aplicarmos o tratamento aqui desenvolvido para implementarmos a análise da nossa amostra de aglomerados ricos da Grande Nuvem de Magalhães.
The snake community of Serra do Mendanha, in Rio de Janeiro State, southeastern Brazil: composition, abundance, richness and diversity in areas with different conservation degrees.

PubMed

Pontes, J A L; Pontes, R C; Rocha, C F D

2009-08-01

We studied and compared parameters of the snake community of the Serra do Mendanha, Rio de Janeiro State, southeastern Brazil (22 degrees 48'-22 degrees 51' S and 43 degrees 31'-43 degrees 28' W), such as: abundance distribution, richness, species diversity and biomass, between forested areas, areas under regeneration and agriculture areas (banana plantations); to obtain information about the natural history and facilitate the development of future research. For capturing the snakes we used: pitfall traps, drift-fences and visual search (diurnal and nocturnal) along four transects for each habitat. The captured snakes were measured with a tape and caliper, weighed with dynamometers and sexed with the use of a catheter. The animals marked (with ventral scales cut) were released for posterior recapture. One individual per species was fixed and deposited at the Museu Nacional, Rio de Janeiro. We undertook an effort of 840 man/hour, and captured a total of 207 snakes belonging to 25 species (Colubridae 80.2%, Elapidae 12.6%, Viperidae 6.3% and Boidae 0.9%). The most abundant were: Liophis miliaris (n = 33), Micrurus corallinus and Chironius fuscus (both with n = 26); the least abundant: Elapomorphus quinquelineatus, Siphlophis compressus and Tropidodryas serra (all with n = 1). The species that contributed the greatest biomass were Spilotes pullatus (7,925 g), Chironius laevicollis (4,694 g), Liophis miliaris (3,675 g) and Pseustes sulphureus (3,050 g); those that contributed the lowest biomass were: Siphlophis compressus, Tropidodryas serra (both with 4 g) and Elapomorphus quinquelineatus (3 g). We found significant differences between the sampled habitats at the Serra do Mendanha (undisturbed forest, secondary forest and banana plantations). The results showed that a great reduction in the abundance, richness, diversity and biomass of the snakes occurs when the native forest is replaced by banana plantations.
Mosquito (Diptera: Culicidae) assemblages associated with Nidularium and Vriesea bromeliads in Serra do Mar, Atlantic Forest, Brazil

PubMed Central

2012-01-01

Background The most substantial and best preserved area of Atlantic Forest is within the biogeographical sub-region of Serra do Mar. The topographic complexity of the region creates a diverse array of microclimates, which can affect species distribution and diversity inside the forest. Given that Atlantic Forest includes highly heterogeneous environments, a diverse and medically important Culicidae assemblage, and possible species co-occurrence, we evaluated mosquito assemblages from bromeliad phytotelmata in Serra do Mar (southeastern Brazil). Methods Larvae and pupae were collected monthly from Nidularium and Vriesea bromeliads between July 2008 and June 2009. Collection sites were divided into landscape categories (lowland, hillslope and hilltop) based on elevation and slope. Correlations between bromeliad mosquito assemblage and environmental variables were assessed using multivariate redundancy analysis. Differences in species diversity between bromeliads within each category of elevation were explored using the Renyi diversity index. Univariate binary logistic regression analyses were used to assess species co-occurrence. Results A total of 2,024 mosquitoes belonging to 22 species were collected. Landscape categories (pseudo-F value = 1.89, p = 0.04), bromeliad water volume (pseudo-F = 2.99, p = 0.03) and bromeliad fullness (Pseudo-F = 4.47, p < 0.01) influenced mosquito assemblage structure. Renyi diversity index show that lowland possesses the highest diversity indices. The presence of An. homunculus was associated with Cx. ocellatus and the presence of An. cruzii was associated with Cx. neglectus, Cx. inimitabilis fuscatus and Cx. worontzowi. Anopheles cruzii and An. homunculus were taken from the same bromeliad, however, the co-occurrence between those two species was not statistically significant. Conclusions One of the main findings of our study was that differences in species among mosquito assemblages were influenced by landscape characteristics. The
Mosquito (Diptera: Culicidae) assemblages associated with Nidularium and Vriesea bromeliads in Serra do Mar, Atlantic Forest, Brazil.

PubMed

Marques, Tatiani C; Bourke, Brian P; Laporta, Gabriel Z; Sallum, Maria Anice Mureb

2012-02-16

The most substantial and best preserved area of Atlantic Forest is within the biogeographical sub-region of Serra do Mar. The topographic complexity of the region creates a diverse array of microclimates, which can affect species distribution and diversity inside the forest. Given that Atlantic Forest includes highly heterogeneous environments, a diverse and medically important Culicidae assemblage, and possible species co-occurrence, we evaluated mosquito assemblages from bromeliad phytotelmata in Serra do Mar (southeastern Brazil). Larvae and pupae were collected monthly from Nidularium and Vriesea bromeliads between July 2008 and June 2009. Collection sites were divided into landscape categories (lowland, hillslope and hilltop) based on elevation and slope. Correlations between bromeliad mosquito assemblage and environmental variables were assessed using multivariate redundancy analysis. Differences in species diversity between bromeliads within each category of elevation were explored using the Renyi diversity index. Univariate binary logistic regression analyses were used to assess species co-occurrence. A total of 2,024 mosquitoes belonging to 22 species were collected. Landscape categories (pseudo-F value = 1.89, p = 0.04), bromeliad water volume (pseudo-F = 2.99, p = 0.03) and bromeliad fullness (Pseudo-F = 4.47, p < 0.01) influenced mosquito assemblage structure. Renyi diversity index show that lowland possesses the highest diversity indices. The presence of An. homunculus was associated with Cx. ocellatus and the presence of An. cruzii was associated with Cx. neglectus, Cx. inimitabilis fuscatus and Cx. worontzowi. Anopheles cruzii and An. homunculus were taken from the same bromeliad, however, the co-occurrence between those two species was not statistically significant. One of the main findings of our study was that differences in species among mosquito assemblages were influenced by landscape characteristics. The bromeliad factor that influenced
Antibacterial activity-guided purification and identification of a novel C-20 oxygenated ent-kaurane from Rabdosia serra (MAXIM.) HARA.

PubMed

Lin, Lianzhu; Zhu, Dashuai; Zou, Linwu; Yang, Bao; Zhao, Mouming

2013-08-15

The objective of this work was to conduct an activity-guided isolation of antibacterial compounds from Rabdosia serra. The ethanol extracts of R. serra leaf and stem were partitioned sequentially into petroleum ether, ethyl acetate, butanol and water fractions, respectively. The ethanol extract of leaf evidenced broad-spectrum antibacterial activity against gram-positive bacterial, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes. The ethyl acetate fractions of leaf and stem exhibited strong inhibition against gram-positive bacteria, and were then purified further. On the basis of antibacterial assay-guided purification, three phenolic compounds (rosmarinic acid, methyl rosmarinate and pedalitin) and four C-20 oxygenated ent-kauranes (effusanin E, lasiodin, rabdosichuanin D and a new compound namely effusanin F) were obtained, whose contents were determined by HPLC analysis. The broth microdilution method confirmed the important inhibition potential of C-20 oxygenated ent-kauranes with low minimum inhibitory concentration (MIC) values. Effusanin E, lasiodin and effusanin F could be useful for the development of new antibacterial agents. Copyright © 2013 Elsevier Ltd. All rights reserved.
The orchid-bee faunas (Hymenoptera: Apidae) of "Reserva Ecológica Michelin", "RPPN Serra Bonita" and one Atlantic Forest remnant in the state of Bahia, Brazil, with new geographic records.

PubMed

Nemésio, A

2014-02-01

The orchid bee faunas of two private natural preserves, 'Reserva Particular do Patrimônio Natural da Serra Bonita' (RSB) and 'Reserva Ecológica Michelin' (REM), and a forest fragment inside the campus of the 'Universidade Estadual de Santa Cruz', were surveyed for the first time. All three areas constitute Atlantic Forest remnants in the southern portion of the state of Bahia, Brazil. A total of 1,782 males belonging to 32 species were actively collected with insect nets during 90 hours of field work from November, 2009, to January, 2012. Euglossa cyanochlora Moure, 1996-one of the rarest orchid bee species-was found at RSB and REM, the latter representing the northernmost record for this species. Euglossa cognata, Moure, 1970 was found at RSB, the northernmost record for this species in the Atlantic Forest and the only recent record for this species at the northern border of Jequitinhonha river.
The plant vacuolar Na+/H+ antiport.

PubMed

Barkla, B J; Apse, M P; Manolson, M F; Blumwald, E

1994-01-01

Salt stress imposes severe limitations on plant growth, however, the extent of growth reduction depends upon the soil salinity level and the plant species. One of the mechanisms employed by salt tolerant plants is the effective vacuolar compartmentalization of sodium. The sequestration of sodium into the vacuole occurs by the operation of a Na+/H+ antiport located at the tonoplast. Evidence for a plant vacuolar Na+/H+ antiport has been demonstrated in tissues, intact vacuoles and isolated tonoplast vesicles. In sugar beet cell suspensions, the activity of the vacuolar Na+/H+ antiport increased with increasing NaCl concentrations in the growth medium. This increased activity was correlated with the increased synthesis of a 170 kDa tonoplast polypeptide. In vivo labelling of tonoplast proteins showed the enhanced synthesis of the 170 kDa polypeptide not only upon exposure of the cells to salt, but also when the cells were grown in the presence of amiloride. Exposure of the cells to amiloride also resulted in increased vacuolar Na+/H+ antiport activity. Polyclonal antibodies raised against the 170 kDa polypeptide almost completely inhibited the antiport activity, suggesting the association of this protein with the plant vacuolar Na+/H+ antiport. Antibodies against the Na+/H+ antiport-associated polypeptide were used to screen a Beta lambda ZAP expression library. A partial clone of 1.65 kb was sequenced and found to encode a polypeptide with a putative transmembrane domain and a large hydrophilic C terminus. This clone showed no homology to any previously cloned gene at either the nucleic acid or the amino acid level.
The Orosirian-Statherian banded iron formation-bearing sequences of the southern border of the Espinhaço Range, Southeast Brazil

NASA Astrophysics Data System (ADS)

Rolim, Vassily Khoury; Rosière, Carlos A.; Santos, João Orestes Schneider; McNaughton, Neal J.

2016-01-01

The Serra da Serpentina and the Serra de São José groups are two distinct banded iron formation-bearing metasedimentary sequences along the eastern border of the southern Espinhaço Range that were deposited on the boundary between the Orosirian and Statherian periods. The Serra da Serpentina Group (SSG) has an Orosirian maximum depositional age (youngest detrital zircon grain age = 1990 ± 16 Ma) and consists of fine clastic metasediments at the base and chemical sediments, including banded iron formations (BIFs), on the top, corresponding to the Meloso and Serra do Sapo formations, respectively, and correlating with the pre-Espinhaço Costa Sena Group. The SSG represents sedimentary deposition on an epicontinental-epeiric, slow downwarping sag basin with little tectonic activity. The younger Serra de São José Group (SJG) is separated from the older SSG by an erosional unconformity and was deposited in a tectonically active continental rift-basin in the early stages of the opening of the Espinhaço Trough. The Serra do São José sediments stretch along the north-south axis of the rift and comprise a complete cycle of transgressive sedimentary deposits, which were subdivided, from base to top, into the Lapão, Itapanhoacanga, Jacém and Canjica formations. The Itapanhoacanga Formation has a maximum depositional age of 1666 ± 32 Ma (Statherian), which coincides with the maximum depositional age (i.e., 1683 ± 11 Ma) of the São João da Chapada Formation, one of the Espinhaço Supergroup's basal units. The Serra de São José Rift and the Espinhaço Rift likely represent the same system, with basal units that are facies variations of the same sequence. The supracrustal rocks have undergone two stages of deformation during the west-verging Brasiliano orogeny that affected the eastern margin of the São Francisco Craton and generated a regional-scale, foreland N-S trending fold-thrust belt, which partially involved the crystalline basement. Thrust faults have
Petrography and chemistry of SiO 2 filling phases in the amethyst geodes from the Serra Geral Formation deposit, Rio Grande do Sul, Brazil

NASA Astrophysics Data System (ADS)

Commin-Fischer, Adriane; Berger, Gilles; Polvé, Mireille; Dubois, Michel; Sardini, Paul; Beaufort, Daniel; Formoso, Milton

2010-04-01

The filling process of amethyst-bearing geodes from Serra Geral Formation basalts, Brazil, is investigated by different methods performed on the SiO 2 filling phases. Image analysis of quartz-amethyst deposits suggests a single growing mechanism ruled by geometric selection of randomly oriented crystals. Microthermometry of fluid inclusions reveals formation temperature lower than 100 °C, probably lower than 50 °C, and fluid salinity as high as 3 mass% NaCl eq. Composition in REE and trace-elements measured by ICP-MS on acid-digested or laser-ablated samples indicates a common genesis for amethyst, quartz and chalcedony, as well as the absence of significant variations from one geode to another. 87Sr/ 86Sr data on chalcedony shows that both the host basalt or the Botucatu sandstone are possible silica sources. These data, combined with thermo-kinetic considerations, permit us to discuss the filling process. We argue in favor of the contribution of a mineralized fluid of hydrothermal origin producing a regional silica source which decreased with time. The observed mineral sequence is related to the depletion of silica in the solution.
Elements concentration analysis in groundwater from the North Serra Geral aquifer in Santa Helena-Brazil using SR-TXRF spectrometer.

PubMed

Justen, Gisele C; Espinoza-Quiñones, Fernando R; Módenes, Aparecido Nivaldo; Bergamasco, Rosangela

2012-01-01

In this work the analysis of elements concentration in groundwater was performed using the synchrotron radiation total-reflection X-ray fluorescence (SR-TXRF) technique. A set of nine tube-wells with serious risk of contamination was chosen to monitor the mean concentration of elements in groundwater from the North Serra Geral aquifer in Santa Helena, Brazil, during 1 year. Element concentrations were determined applying a SR-TXRF methodology. The accuracy of SR-TXRF technique was validated by analysis of a certified reference material. As the groundwater composition in the North Serra Geral aquifer showed heterogeneity in the spatial distribution of eight major elements, a hierarchical clustering to the data was performed. By a similarity in their compositions, two of the nine wells were grouped in a first cluster, while the other seven were grouped in a second cluster. Calcium was the major element in all wells, with higher Ca concentration in the second cluster than in the first cluster. However, concentrations of Ti, V, Cr in the first cluster are slightly higher than those in the second cluster. The findings of this study within a monitoring program of tube-wells could provide a useful assessment of controls over groundwater composition and support management at regional level.
Teaching and Popularization of Astronomy in Latin America by the Liada Perspective. (Spanish Title: Enseñanza y Divulgación de la Astronomía en la América Latina en la Perspectiva de la Liada.) Ensino e Divulgação da Astronomia na América Latina na Perspectiva da Liada

NASA Astrophysics Data System (ADS)

Bretones, Paulo Sergio

2008-12-01

disponibilizados en la página de la Sección, faz-se una análisis y discusión sobre la importancia de tales relatos para finalidades educacionales. Es presentada una Hoja de reporte elaborado como sugestión para presentación de relatos por parte de individuos y instituciones ben como discutida la importancia de la sistematización de experiencias visando mayor visibilidad y cambio de informaciones en el área. Concluí con una evaluación de los proyectos, su potencial y limitaciones, ben como sugestiones de proyectos futuros visando mayor interacción entre los países de la América Latina y tornando disponible la Sección para esta finalidad.
Esse trabalho visa divulgar e analisar as atividades da Seção de Ensino e Divulgação de Astronomia (SEDA) da Liga Iberoamericana de Astronomia (LIADA). Após um histórico da LIADA, são apresentados os diversos projetos da Seção que conta com a colaboração de coordenadores locais na maioria dos países da América Latina. São apresentados os projetos que visam chamar a atenção do público em geral, estudantes e professores para a observação do céu e posterior envio de relatos para colocação na página da Seção na Internet. Mais especificamente são analisados os projetos e relatos relacionados aos eclipses ocorridos desde o ano 2000. Utilizando-se os arquivos disponibilizados na página da Seção, faz-se uma análise e discussão sobre a importância de tais relatos para finalidades educacionais. É apresentado um formulário elaborado como sugestão para apresentação de relatos por parte de indivíduos e instituições bem como discutida a importância da sistematização de experiências visando maior visibilidade e troca de informações na área. Conclui com uma avaliação dos projetos, seu potencial e limitações, bem como sugestões de projetos futuros visando maior interação entre os países da América Latina e tornando disponível a Seção para esta finalidade.
Seasonally warmer and humid climates in a lower paleolatitude position of southern Brazil (Paraná Basin): new findings of the Lueckisporites virkkiae zone (late Cisuralian-Guadalupian) in the Serra do Rio do Rastro and neighboring localities

NASA Astrophysics Data System (ADS)

di Pasquo, Mercedes; Souza, Paulo A.; Kavali, Pauline Sabina; Felix, Cristina

2018-03-01

First palynological information from surface samples of the Serra Alta and Rio do Rasto formations (Passa Dois Group, Paraná Basin), exposed in the Serra do Rio do Rastro (White's Column) and Urubici regions in Santa Catarina State (Brazil) is presented. The Serra Alta Formation is transitionally deposited over the Irati Formation, which is constrained to the late Artinskian/Kungurian by different paleontological and radiometric data. Twelve productive samples (of forty) yielded fairly well preserved palynomorphs, dominated by striate and non striate bisaccate and asaccate pollen grains and subordinated trilete and monolete spores, monosaccate pollen grains and Botryococcus. Diagnostic species of the Lueckisporites virkkiae Zone (Artinskian-Guadalupian) in the Paraná Basin are recorded along with few species of Guadalupian-Lopingian age (e.g. Cladaitina veteadensis, Guttulapollenites hannonicus, Lophotriletes parryensis, Protohaploxypinus microcorpus, Staurosaccites quadrifidus, Weylandites cincinnatus). They support a Kungurian-?Roadian age for the Serra Alta, and a Capitanian (?Lopingian) age for the Rio do Rasto formations. Four samples from the Sete Quedas outcrop yielded scarce and poorly preserved specimens of Lueckisporites likely due to weathering. A statistic comparison among our assemblages and selected Permian palynozones and palynofloras from South America supports a closer correlation with the La Veteada Formation (Guadalupian-Lopingian) from western Argentina due to common occurrence of all the species, and with the Striatites Zone (late Artinskian-Kungurian) of the Chacoparaná Basin, and the I-S Zone Melo Formation in Uruguay. The botanical affinities of the palynomorphs from both assemblages indicate the presence of spores of hygro-mesophytic affinities along with meso-xerophyle pollen grains, which is in agreement with seasonally warmer and humid climates favored by a lower paleolatitude position. The presence of pyrite in some of the miospore

Phlebotomine Sand Fly Fauna and Leishmania Infection in the Vicinity of the Serra do Cipó National Park, a Natural Brazilian Heritage Site

PubMed Central

Lana, Rosana Silva; Michalsky, Érika Monteiro; Fortes-Dias, Consuelo Latorre; França-Silva, João Carlos; Lara-Silva, Fabiana de Oliveira; Lima, Ana Cristina Vianna Mariano da Rocha; Moreira de Avelar, Daniel; Martins, Juliana Cristina Dias; Dias, Edelberto Santos

2015-01-01

In the New World, the leishmaniases are primarily transmitted to humans through the bites of Leishmania-infected Lutzomyia (Diptera: Psychodidae) phlebotomine sand flies. Any or both of two basic clinical forms of these diseases are endemic to several cities in Brazil—the American cutaneous leishmaniasis (ACL) and the American visceral leishmaniasis (AVL). The present study was conducted in the urban area of a small-sized Brazilian municipality (Jaboticatubas), in which three cases of AVL and nine of ACL have been reported in the last five years. Jaboticatubas is an important tourism hub, as it includes a major part of the Serra do Cipó National Park. Currently, no local data is available on the entomological fauna or circulating Leishmania. During the one-year period of this study, we captured 3,104 phlebotomine sand flies belonging to sixteen Lutzomyia species. In addition to identifying incriminated or suspected vectors of ACL with DNA of the etiological agent of AVL and vice versa, we also detected Leishmania DNA in unexpected Lutzomyia species. The expressive presence of vectors and natural Leishmania infection indicates favorable conditions for the spreading of leishmaniases in the vicinity of the Serra do Cipó National Park. PMID:25793193
Phlebotomine sand fly fauna and leishmania infection in the vicinity of the Serra do Cipó National Park, a natural Brazilian heritage site.

PubMed

Lana, Rosana Silva; Michalsky, Érika Monteiro; Fortes-Dias, Consuelo Latorre; França-Silva, João Carlos; Lara-Silva, Fabiana de Oliveira; Lima, Ana Cristina Vianna Mariano da Rocha; Moreira de Avelar, Daniel; Martins, Juliana Cristina Dias; Dias, Edelberto Santos

2015-01-01

In the New World, the leishmaniases are primarily transmitted to humans through the bites of Leishmania-infected Lutzomyia (Diptera: Psychodidae) phlebotomine sand flies. Any or both of two basic clinical forms of these diseases are endemic to several cities in Brazil--the American cutaneous leishmaniasis (ACL) and the American visceral leishmaniasis (AVL). The present study was conducted in the urban area of a small-sized Brazilian municipality (Jaboticatubas), in which three cases of AVL and nine of ACL have been reported in the last five years. Jaboticatubas is an important tourism hub, as it includes a major part of the Serra do Cipó National Park. Currently, no local data is available on the entomological fauna or circulating Leishmania. During the one-year period of this study, we captured 3,104 phlebotomine sand flies belonging to sixteen Lutzomyia species. In addition to identifying incriminated or suspected vectors of ACL with DNA of the etiological agent of AVL and vice versa, we also detected Leishmania DNA in unexpected Lutzomyia species. The expressive presence of vectors and natural Leishmania infection indicates favorable conditions for the spreading of leishmaniases in the vicinity of the Serra do Cipó National Park.
Molecular modeling and molecular dynamics simulations based structural analysis of the SG2NA protein variants.

PubMed

Soni, Sangeeta; Tyagi, Chetna; Grover, Abhinav; Goswami, Shyamal K

2014-07-11

SG2NA is a member of the striatin sub-family of WD-40 repeat proteins. Striatin family members have been associated with diverse physiological functions. SG2NA has also been shown to have roles in cell cycle progression, signal transduction etc. They have been known to interact with a number of proteins including Caveolin and Calmodulin and also propagate the formation of a multimeric protein unit called striatin-interacting phosphatase and kinase. As a pre-requisite for such interaction ability, these proteins are known to be unstable and primarily disordered in their arrangement. Earlier we had identified that it has multiple isoforms (namely 35, 78, 87 kDa based on its molecular weight) which are generated by alternative splicing. However, detailed structural information of SG2NA is still eluding the researchers. This study was aimed towards three-dimensional molecular modeling and characterization of SG2NA protein and its isoforms. One structure out of five was selected for each variant having the least value for C score. Out of these, m35 kDa with a C score value of -3.21 was the most poorly determined structure in comparison to m78 kDa and m87 kDa variants with C scores of -1.16 and -1.97 respectively. Further evaluation resulted in about 61.6% residues of m35 kDa, 76.6% residues of m78 kDa and 72.1% residues of m87 kDa falling in the favorable regions of Ramchandran Plot. Molecular dynamics simulations were also carried out to obtain biologically relevant structural models and compared with previous atomic coordinates. N-terminal region of all variants was found to be highly disordered. This study provides first-hand detailed information to understand the structural conformation of SG2NA protein variants (m35 kDa, m78 kDa and m87 kDa). The WD-40 repeat domain was found to constitute antiparallel strands of β-sheets arranged circularly. This study elucidates the crucial structural features of SG2NA proteins which are involved in various protein
Electron spin resonance dating of human teeth from Toca da Santa shelter of São Raimundo Nonato, Piauí, Brazil

NASA Astrophysics Data System (ADS)

Kinoshita, A.; Figueiredo, A. M. G.; Felice, G. D.; Lage, M. C. S. M.; Guidon, N.; Baffa, O.

2008-02-01

Results of the dating of fossil human teeth excavated from a shelter in the surroundings areas of the Serra da Capivara National Park, São Raimundo Nonato, Piauí, Brazil are presented. This shelter was partially excavated to search for more data that could improve the archaeological context of the Garrincho’s limestone hill sites, where the Toca do Gordo do Garrincho shelter provided two human teeth dated by conventional C-14 in (12,170 ± 40) yBP (years before present) and calibrated age (2 Sigma, 95% probability) 15,245 14,690 yBP (Beta 136204) [E. Peyre, C. Guérin, N. Guidon, I. Coppens, CR Acad. Sci. Paris, Sciences de la terre et des planètes/ Earth & Planetary Sciences 327 (1998) 335, [1
Basaltic ring structures of the Serra Geral Formation at the southern Triângulo Mineiro, Água Vermelha region, Brazil

NASA Astrophysics Data System (ADS)

Pacheco, Fernando Estevão Rodrigues Crincoli; Caxito, Fabricio de Andrade; Moraes, Lucia Castanheira de; Marangoni, Yara Regina; Santos, Roberto Paulo Zanon dos; Pedrosa-Soares, Antonio Carlos

2018-04-01

The Serra Geral Formation constitutes a continental magmatic province on the southern part of South America within the Paraná basin. Basaltic magmatism of the Serra Geral Formation occurred as extrusions at around 134.5 to 131.5 My ago. The formation is part of the Paraná-Etendeka large igneous province, spanning South America and southwestern Africa. The main extrusion mechanism was probably through fissures related to extensional regime during the breakup of Gondwana in the Cretaceous. Basaltic ring structures (BRS) with tens of meters of diameter, cropping out downstream of Grande river at Água Vermelha hydroelectric dam in southern Triângulo Mineiro region, enable the study of the mechanism of extrusion. The origin of the BRS has been subject to differing interpretations in the past, either collapsed lava flows or central conduits. Detailed geological mapping at 1:1000 scale, stratigraphic, petrographic and gravimetric analysis of the most well preserved of the BRS, with a 200 m diameter, has enabled the description of thirteen different basalt lava flows, along with single a central lava lake and a ring dyke structure. The central flow, interpreted as a preserved lava lake, comprises vesicle- and amygdale-rich basalt, spatter, ropy and degassing structures. The most basal of the thirteen lava flows has massive basalt containing geodes filled with quartz. Above, the lava flows show massive basalt with vertical columnar jointing where is possible to identify the top and bottom of each individual flow, with gentle dips towards the perimeter of the structure. A prominent ring dyke dipping towards the lava lake presents horizontal columnar jointing and cuts the basal and central flows. The gravimetric analysis shows a weak negative Bouguer anomaly on the center of the BRS. The proposed model describes the volcanism of the region in three main steps: (1) fissure flow occurs with lava input; (2) this lava cools and crystallizes cementing most of the fissures
Short-range ensemble predictions based on convection perturbations in the Eta Model for the Serra do Mar region in Brazil

NASA Astrophysics Data System (ADS)

Bustamante, J. F. F.; Chou, S. C.; Gomes, J. L.

2009-04-01

The Southeast Brazil, in the coastal and mountain region called Serra do Mar, between Sao Paulo and Rio de Janeiro, is subject to frequent events of landslides and floods. The Eta Model has been producing good quality forecasts over South America at about 40-km horizontal resolution. For that type of hazards, however, more detailed and probabilistic information on the risks should be provided with the forecasts. Thus, a short-range ensemble prediction system (SREPS) based on the Eta Model is being constructed. Ensemble members derived from perturbed initial and lateral boundary conditions did not provide enough spread for the forecasts. Members with model physics perturbation are being included and tested. The objective of this work is to construct more members for the Eta SREPS by adding physics perturbed members. The Eta Model is configured at 10-km resolution and 38 layers in the vertical. The domain covered is most of Southeast Brazil, centered over the Serra do Mar region. The constructed members comprise variations of the cumulus parameterization Betts-Miller-Janjic (BMJ) and Kain-Fritsch (KF) schemes. Three members were constructed from the BMJ scheme by varying the deficit of saturation pressure profile over land and sea, and 2 members of the KF scheme were included using the standard KF and a momentum flux added to KF scheme version. One of the runs with BMJ scheme is the control run as it was used for the initial condition perturbation SREPS. The forecasts were tested for 6 cases of South America Convergence Zone (SACZ) events. The SACZ is a common summer season feature of Southern Hemisphere that causes persistent rain for a few days over the Southeast Brazil and it frequently organizes over Serra do Mar region. These events are particularly interesting because of the persistent rains that can accumulate large amounts and cause generalized landslides and death. With respect to precipitation, the KF scheme versions have shown to be able to reach the
VIII Olimpíada Brasileira de Astronomia e Astronáutica

NASA Astrophysics Data System (ADS)

Garcia Canalle, João Batista; Villas da Rocha, Jaime Fernando; Wuensche de Souza, Carlos Alexandre; Pereira Ortiz, Roberto; Aguilera, Nuricel Villalonga; Padilha, Maria De Fátima Catta Preta; Pessoa Filho, José Bezerra; Soares Rodrigues, Ivette Maria

2007-07-01

Neste trabalho apresentamos as motivações pelas quais organizamos, em conjunto, pela primeira vez, a Olimpíada Brasileira de Astronomia incluindo a Astronáutica, em colaboração com a Agência Espacial Brasileira. Esta ampliação contribuiu para atrair ainda mais alunos, professores, escolas e patrocinadores para participarem desta Olimpíada. Em 2005 participaram da VIII Olimpíada Brasileira de Astronomia e Astronáutica (VIII OBA) 187.726 alunos distribuídos por 3.229 escolas, pertencentes a todos os estados brasileiros, incluindo o Distrito Federal. O crescimento em número de alunos participantes foi 52,4% maior do que em 2004. Em abril de 2005 organizamos, em Itapecerica da Serra, SP, um curso para os 50 alunos previamente selecionados e participantes da VII OBA e ao final selecionamos, dentre eles, uma equipe de 5 alunos, os quais representaram o Brasil na X Olimpíada Internacional de Astronomia, na China, em outubro de 2005. Ganhamos, pela primeira vez, uma medalha de ouro naquele evento. Em Agosto de 2005, organizamos a VIII Escola de Agosto para 50 alunos e respectivos professores, em Águas de Lindóia, SP, juntamente com a XXXI reunião anual da Sociedade Astronômica Brasileira (SAB). Em novembro de 2005 realizamos a I Jornada Espacial, em São José dos Campos, com 22 alunos e 22 professores selecionados dentre os participantes que melhores resultados obtiveram nas questões de Astronáutica da VIII OBA. Neste trabalho detalhamos os resultados da VIII OBA bem como as ações subseqüentes.
ESR dating of Smilodon populator from Toca de Cima dos Pilão, Piauí, Brazil.

PubMed

Kinoshita, Angela; Mollemberg, Michelle; Santana, William; G Figueiredo, Ana Maria; Guidon, Niede; Fátima da Luz, Maria de; Guérin, Claude; Baffa, Oswaldo

2017-02-01

Smilodon is a genus of big cats that lived from the early to the late Pleistocene in regions extending from North to South America. The fossil records of the "saber-toothed cats" are uneven, with some taxa being quite abundant in certain regions. In Brazil, Smilodon populator is a well-known species whose remains, although scarce in comparison to other large mammals, are found all across the country. In particular, there are multiple records of this species in the region of the Serra da Capivara National Park. This area was home to a rich Pleistocene-Holocene fauna, including many mammals. Here, we report on the Electron Spin Resonance dating of a Smilodon populator tooth found in "Toca de Cima dos Pilão", located in the surroundings of the Serra da Capivara National Park. The equivalent dose found after exponential fitting of dose-response curve was (2.7±0.3)x10 2 Gy. Neutron Activation Analysis was used to determine the concentration of radioisotopes present in the sample and in the sediment to calculate the internal and external dose rates. The result of age found is 93±9ka, which confirmed the presence of this species in Serra da Capivara National Park in the late Pleistocene. Copyright © 2016 Elsevier Ltd. All rights reserved.
Expression of Na+-glucose cotransporter (SGLT1) in visceral and parietal mesothelium of rabbit pleura.

PubMed

Sironi, Chiara; Bodega, Francesca; Porta, Cristina; Zocchi, Luciano; Agostoni, Emilio

2007-10-15

Indirect evidence for a solute-coupled liquid absorption from rabbit pleural space indicated that it should be caused by a Na(+)/H(+)-Cl(-)/HCO(3)(-) double exchanger and a Na(+)-glucose cotransporter [Agostoni, E., Zocchi, L., 1998. Mechanical coupling and liquid exchanges in the pleural space. In: Antony, V.B. (Ed.), Clinics in Chest Medicine: Diseases of the Pleura, vol. 19. Saunders, Philadelphia, pp. 241-260]. In this research we tried to obtain molecular evidence for Na(+)-glucose cotransporter (SGLT1) in visceral and parietal mesothelium of rabbit pleura. To this end we performed immunoblot assays on total protein extracts of scraped visceral or parietal mesothelium of rabbits. These showed two bands: one at 72kDa (m.w. of SGLT1), and one at 55kDa (which should also provide Na(+)-glucose cotransport). Both bands disappeared in assays in which SGLT1 antibody was preadsorbed with specific antigen. Molecular evidence for Na(+)/K(+) ATPase (alpha1 subunit) was also provided. Immunoblot assays for SGLT1 on cultured mesothelial cells of rabbit pleura showed a band at 72kDa, and in some cases also at 55kDa, irrespectively of treatment with a differentiating agent. Solute-coupled liquid absorption hinders liquid filtration through parietal mesothelium caused by Starling forces, and favours liquid absorption through visceral mesothelium caused by these forces.
Paleoenvironmental Evolution of Continental Carbonates in West-Central Brazil.

PubMed

Oliveira, Emiliano C; Rossetti, Dilce F; Utida, Giselle

2017-05-01

This paper presents a sedimentological and stratigraphical study of Quaternary (Middle to Late Pleistocene/Holocene) continental carbonates outcrops inside Pantanal Basin and its surroundings, especially in Serra da Bodoquena, Pantanal do Miranda and Corumbá/Ladário plateau, in the state of Mato Grosso do Sul, as well as in Serra das Araras, in the state of Mato Grosso. The aim is to understand the depositional paleoenvironments and analyse climate and tectonic influences in their genesis and evolution. The results show that the deposition of these continental carbonates started in the Middle to Late Pleistocene and have continued, with some interruptions, until the present days. Sedimentary successions were identified in the different areas, without complete correlation. Two sedimentary successions separated by an erosional surface were described in Serra da Bodoquena and Serra das Araras. In Corumbá and Pantanal do Miranda, only one succession was described. These successions were deposited in elongated lakes parallel to fault planes; small lakes, related plains and plateaus; springs related to cliffs produced by faulting; rivers conditioned by topographic variation. The climatic interpretation, without proper temporal resolution, obtained by the stable-isotope composition and stratigraphic interpretation, indicates alternation of dry and wet periods. The Neoproterozoic faults with their neotectonics and the subsidence of the Pantanal Basin, are the major control for carbonated water flow and development of depositional areas, gradually turning plateaus into slight tilted areas, allowing the evolution of depositional systems from lakes to rivers.
Geomorphology Influencing the Diversification of Fish in Small-Order Rivers of Neighboring Basins.

PubMed

Morais-Silva, João P; Oliveira, Alessandra V de; Fabrin, Thomaz M C; Diamante, Nathália Alves; Prioli, Sônia M A P; Frota, Augusto; Graça, Weferson J da; Prioli, Alberto J

2018-03-13

The current analysis investigates whether the uplift of the Serra da Esperança and the Ponta Grossa Arch in the Serra Geral resulted in ichthyofaunistic changes in adjacent basins. For this, we describe the phylogeographic structure among populations of Trichomycterus collected in hydrographic basins in southern Brazil by using partial nucleotide sequences of the mitochondrial gene Cytochrome C Oxidase subunit I. Analyses revealed that the nomenclature Trichomycterus davisi fails to contain the whole genetic diversity range found in the collected specimens and indicates at least six genetic lineages in Trichomycterus. Diagnostic morphological characteristics not associated to T. davisi could be identified in some specimens from the Iguaçu Piquiri haplogroup, indicating the occurrence of species Trichomycterus stawiarski. The lack of morphological differences among the other clades clearly suggests a cryptic species case. Molecular analyses revealed at least five new species besides T. davisi in the hydrographic basins and support the interpretation that genetic structure in T. davisi species complex is explained by tectonic events intrinsic to the areas of influence of Serra da Esperança and the Ponta Grossa Arch which occurred around 1.7 My.
Resultados a longo prazo da angioplastia de artérias renais com stent na doença aterosclerótica: revisão sistemática

PubMed Central

Siqueira, Daniel Emilio Dalledone; Guillaumon, Ana Terezinha

2017-01-01

Resumo A doença renovascular aterosclerótica é a principal causa de hipertensão secundária. A história natural da doença demonstra taxas de progressão de 4 a 12% ao ano. Entre os métodos de tratamento existe a angioplastia com stent de artérias renais; porém, poucos estudos clínicos demonstraram seus resultados a longo prazo. Esta revisão sistemática da literatura se propõe a apresentar os resultados a longo prazo (acima de 24 meses) da angioplastia com stent de artérias renais na doença aterosclerótica em relação à função renal e aos níveis pressóricos no controle da hipertensão. Foi realizada uma ampla pesquisa, utilizando os termos apropriados, nas bases de dados LILACS, EMBASE, SCIELO, Cochrane Library e MEDLINE. De um total de 2.170 referências, apenas sete artigos contemplavam todos os critérios de inclusão. Conclui-se que, a longo prazo, há uma estabilização da função renal, redução dos níveis pressóricos e diminuição do número de classes de medicamentos anti-hipertensivos. PMID:29930639
A possible mechanism for low affinity of silkworm Na+/K+-ATPase for K.

PubMed

Homareda, Haruo; Otsu, Masahiro; Yamamoto, Sachiko; Ushimaru, Makoto; Ito, Sayaka; Fukutomi, Toshiyuki; Jo, Taeho; Eishi, Yoshinobu; Hara, Yukichi

2017-12-01

The affinity for K + of silkworm nerve Na + /K + -ATPase is markedly lower than that of mammalian Na + /K + -ATPase (Homareda 2010). In order to obtain clues on the molecular basis of the difference in K + affinities, we cloned cDNAs of silkworm (Bombyx mori) nerve Na + /K + -ATPase α and β subunits, and analyzed the deduced amino acid sequences. The molecular masses of the α and β subunits were presumed to be 111.5 kDa with ten transmembrane segments and 37.7 kDa with a single transmembrane segment, respectively. The α subunit showed 75% identity and 93% homology with the pig Na + /K + -ATPase α1 subunit. On the other hand, the amino acid identity of the β subunit with mammalian counterparts was as low as 30%. Cloned α and β cDNAs were co-expressed in cultured silkworm ovary-derived cells, BM-N cells, which lack endogenous Na + /K + -ATPase. Na + /K + -ATPase expressed in the cultured cells showed a low affinity for K + and a high affinity for Na + , characteristic of the silkworm nerve Na + /K + -ATPase. These results suggest that the β subunit is responsible for the affinity for K + of Na + /K + -ATPase.
Determinação da composição química em nebulosas planetárias na direção do anticentro galáctico

NASA Astrophysics Data System (ADS)

Costa, R. D. D.; Uchida, M. M. M.; Maciel, W. J.

2003-08-01

Existe um gradiente radial de abundâncias no disco galáctico, cujo comportamento é razoavelmente bem conhecido para distâncias galactocêntricas entre 3 e 10 kpc. Foi obtido a partir de resultados derivados de nebulosas planetárias, regiões HII e estrelas, como as estrelas quentes de tipo O, B e aglomerados abertos. Com o objetivo de investigar o comportamento deste gradiente radial na região externa do disco, conhecida como anticentro galáctico, reportamos aqui os resultados finais da análise de uma amostra de nebulosas planetárias na direção do anticentro, observadas no LNA e no ESO entre 1995 e 2000. O uso de nebulosas planetárias permite o cálculo das abundâncias de elementos traçadores da evolução química do disco como oxigênio, argônio e neônio com o uso de técnicas de espectroscopia nebular. Os resultados indicam uma distribuição de abundâncias distinta daquela encontrada na vizinhança solar, mostrando que o gradiente radial diminui sensivelmente para distâncias galactocêntricas maiores que 10 kpc. Este resultado está de acordo com os mais recentes modelos de evolução química do disco, que prevêem uma diminuição ou mesmo um desaparecimento do gradiente radial no bordo externo do disco galáctico. (FAPESP/CNPq)
Physiological responses to salt stress of salt-adapted and directly salt (NaCl and NaCl+Na2SO4 mixture)-stressed cyanobacterium Anabaena fertilissima.

PubMed

Swapnil, Prashant; Rai, Ashwani K

2018-05-01

Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (Na 2 SO 4 ). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+Na 2 SO 4 mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly. Salinity impaired gross photosynthesis, electron transport activities, and respiration in parent cells, but not in the salt-adapted cells, except a marginal increase in PSI activity. Despite higher Na + concentration in the salt mixture, equimolar NaCl appeared more inhibitive to growth. Sucrose and trehalose content and antioxidant activities were maximal in 250 mM NaCl-treated cells, followed by salt mixture and was almost identical in salt-adapted (exposed to 500 mm NaCl) and control cells, except a marginal increase in ascorbate peroxidase activity and an additional fourth superoxide dismutase isoform. Catalase isoform of 63 kDa was induced only in salt-stressed cells. Salinity increased the uptake of intracellular Na + and Ca 2+ and leakage of K + in parent cells, while cation level in salt-adapted cells was comparable to control. Though there was differential increase in intracellular Ca 2+ under different salt treatments, ratio of Ca 2+ /Na + remained the same. It is inferred that stepwise increment in the salt concentration enabled the cyanobacterium to undergo priming effect and acquire robust and efficient defense system involving the least energy.
Thematic mapping of likely target areas for the occurence of cassiterite in the Serra do Mocambo (GO) granitic massifs using LANDSAT 2 digital imaging

NASA Technical Reports Server (NTRS)

Almeidofilho, R. (Principal Investigator)

1984-01-01

The applicability of LANDSAT/MSS images, enhanced by computer derived techniques, as essential tools in mineral research was investigated and the Serra do Mocambo granitic massif was used as illustration. Given the peculiar factors founded in this area, orbital imagery permitted the delineation of potential target areas of mineralization occurrences, associated to albitized/greisenized types. Follow up prospection for primary tin deposits in this granitic massif should be restricted to the delineated areas which are less than 5% of the total superficial area of the massif.
Feeding ecology of the lizard Tropidurus oreadicus Rodrigues 1987 (Tropiduridae) at Serra dos Carajás, Pará state, northern Brazil.

PubMed

Rocha, C F D; Siqueira, C C

2008-02-01

Tropidurus species commonly prey on arthropods, but they may also feed on vertebrates and plant material. The lizard Tropidurus oreadicus (Tropiduridae) is common in open vegetation habitats and generally has sexual dimorphism. In this study we analyzed the diet of T. oreadicus at Serra dos Carajás, Pará, in the north of Brazil. Snout-vent length (SVL) and jaw width (JW) were taken for 34 lizards. There was a significant difference in SVL and in JW, with males being larger than females. All lizards analyzed contained food in their stomachs. The diet of T. oreadicus at Serra dos Carajás was characterized by the consumption of a relative wide spectrum of food item categories (21 types of items), consisting of arthropods, part of one vertebrate and plant material, which characterizes the diet of a generalist predator. Volumetrically, the most important items in the diet of both sexes of T. oreadicus were flowers (M = 61.7%; F = 33%) and orthopterans (M = 1.7%; F = 3.5%). Ants were the most frequently consumed (100% for both sexes) and the most numerous (M = 94.5%; F = 89.4%) food item. Flowers also were frequently consumed (M = 91.7%; F = 54.5%), with their relative consumption differing significantly between sexes. There was not a significant sexual difference in prey volume, neither in number of preys per stomach, nor in type of prey ingested. There was no relationship between lizard jaw width and the mean volume of prey. The data showed that T. oreadicus is a relatively generalist lizard in terms of diet and that consumes large volumes of plant material, especially flowers of one species of genus Cassia.
Voltage-dependent neuromodulation of Na+ channels by D1-like dopamine receptors in rat hippocampal neurons.

PubMed

Cantrell, A R; Scheuer, T; Catterall, W A

1999-07-01

Activation of D1-like dopamine (DA) receptors reduces peak Na+ current in acutely isolated hippocampal neurons through phosphorylation of the alpha subunit of the Na+ channel by cAMP-dependent protein kinase (PKA). Here we report that neuromodulation of Na+ currents by DA receptors via PKA is voltage-dependent in the range of -110 to -70 mV and is also sensitive to concurrent activation of protein kinase C (PKC). Depolarization enhanced the ability of D1-like DA receptors to reduce peak Na+ currents via the PKA pathway. Similar voltage-dependent modulation was observed when PKA was activated directly with the membrane-permeant PKA activator DCl-cBIMPS (cBIMPS; 20 microM), indicating that the membrane potential dependence occurs downstream of PKA. PKA activation caused only a small (-2.9 mV) shift in the voltage dependence of steady-state inactivation and had no effect on slow inactivation or on the rates of entry into the fast or slow inactivated states, suggesting that another mechanism is responsible for coupling of membrane potential changes to PKA modulation. Activation of PKC with a low concentration of the membrane-permeant diacylglycerol analog oleylacetyl glycerol also potentiated modulation by SKF 81297 or cBIMPS, and these effects were most striking at hyperpolarized membrane potentials where PKA modulation was not stimulated by membrane depolarization. Thus, activation of D1-like DA receptors causes a strong reduction in Na+ current via the PKA pathway, but it is effective primarily when it is combined with depolarization or activation of PKC. The convergence of these three distinct signaling modalities on the Na+ channel provides an intriguing mechanism for integration of information from multiple signaling pathways in the hippocampus and CNS.
Assessment of risk to human health from simultaneous exposure to multiple contaminants in an artisanal gold mine in Serra Pelada, Pará, Brazil.

PubMed

de Souza, Edna Santos; Texeira, Renato Alves; da Costa, Hercília Samara Cardoso; Oliveira, Fábio Júnior; Melo, Leônidas Carrijo Azevedo; do Carmo Freitas Faial, Kelson; Fernandes, Antonio Rodrigues

2017-01-15

Contamination of soil, water and plants caused by gold mining is of great societal concern because of the risk of environmental pollution and risk to human health. The aim of the present study was to evaluate the risk to human health from ingestion of As, Ba, Co, Cu, Cd, Cr, Ni, Pb, Se and Ni present in soil, sterile and mineralized waste, and water and plants at a gold mine in Serra Pelada, Pará, Brazil. Samples of soil, sterile and mineralized waste, water and plants were collected around an artisanal gold mine located in Serra Pelada. The mean concentrations of potentially toxic elements in the soil were higher than the soil quality reference values as defined in the legislation, which may be attributeable to past mining activities. Water from the area close to the mine exhibited As, Ba and Pb concentrations exceeding the reference values established by the World Health Organization, deemed unfit for human consumption. Plants exhibited high Pb concentrations, representing a food safety risk to the population. The mean hazard index (HI) values were below the acceptable limit (1.0) established by the United States Environmental Protection Agency, although the highest HI values observed for adults and children were higher than the respective acceptable limits. Environmental contamination and risk to human health were heterogeneous in the surroundings of the mine. Mitigation strategies need to be adopted to decrease the risks of contamination to the environment and to the local population. Copyright © 2016 Elsevier B.V. All rights reserved.
Mapping soil erosion risk in Serra de Grândola (Portugal)

NASA Astrophysics Data System (ADS)

Neto Paixão, H. M.; Granja Martins, F. M.; Zavala, L. M.; Jordán, A.; Bellinfante, N.

2012-04-01

Geomorphological processes can pose environmental risks to people and economical activities. Information and a better knowledge of the genesis of these processes is important for environmental planning, since it allows to model, quantify and classify risks, what can mitigate the threats. The objective of this research is to assess the soil erosion risk in Serra de Grândola, which is a north-south oriented mountain ridge with an altitude of 383 m, located in southwest of Alentejo (southern Portugal). The study area is 675 km2, including the councils of Grândola, Santiago do Cacém and Sines. The process for mapping of erosive status was based on the guidelines for measuring and mapping the processes of erosion of coastal areas of the Mediterranean proposed by PAP/RAC (1997), developed and later modified by other authors in different areas. This method is based on the application of a geographic information system that integrates different types of spatial information inserted into a digital terrain model and in their derivative models. Erosive status are classified using information from soil erodibility, slope, land use and vegetation cover. The rainfall erosivity map was obtained using the modified Fournier index, calculated from the mean monthly rainfall, as recorded in 30 meteorological stations with influence in the study area. Finally, the soil erosion risk map was designed by ovelaying the erosive status map and the rainfall erosivity map.

Four new species of Luciuranus fireflies from the Brazilian Atlantic Rainforest (Coleoptera: Lampyridae).

PubMed

Silveira, Luiz F L da; Souto, Paula M; Mermudes, J R M

2018-04-20

Luciuranus Silveira, Khattar Mermudes, 2016 is a firefly genus whose species bear an intricate, species-specific lock-and-key mechanism of reproductive isolation. Here we propose four new species, Luciuranus magnoculus sp. nov., L. desideratus sp. nov., L. takiyae sp. nov. and L. carioca sp. nov., and provide illustrations of their diagnostic features and an updated key to species. As previously reported for their congenerics, each of the four new species have stereotypical morphology of both male and female terminalia, and are regarded as prima facie endemics of single massifs of the Serra da Mantiqueira and Serra do Mar, in the Brazilian Atlantic Rainforest.
From the Guiana Highlands to the Brazilian Atlantic Rain Forest: four new species of Selaginella (Selaginellaceae – Lycopodiophyta: S. agioneuma, S. magnafornensis, S. ventricosa, and S. zartmanii)

PubMed Central

López, Christian A.; Sierra, Adriel M.; Ceballos, Jorge

2018-01-01

We describe four new species in the genus Selaginella (i.e., S. agioneuma, S. magnafornensis, S. ventricosa, and S. zartmanii) from Brazil, all presently classified in subg. Stachygynandrum. For each of the new taxa we discuss taxonomic affinities and provide information on habitat, distribution, and conservation status. In addition, line drawings and scanning electron microscope (SEM) images of stems sections, leaves, and spores (when present) are included. Selaginella agioneuma and S. magnafornensis are from the State of Espíritu Santo where they inhabit premontane to montane Atlantic rain forests in the Reserva Biológica Augusto Ruschi and Parque Estadual Forno Grande, respectively. Selaginella ventricosa was collected in upper montane forests at Parque Nacional Serra da Mocidade, State of Roraima and S. zartmanii in premontane Amazon rain forests on upper Rio Negro at Mpio. São Gabriel da Cachoeira, Amazonas State in both Serra Curicuriari and the Morro dos Seis Lagos Biological Reserve. PMID:29770272
Environmental benefits and concerns on safety: communicating latest results on nanotechnology safety research-the project DaNa2.0.

PubMed

Kühnel, D; Marquardt, C; Nau, K; Krug, H F; Paul, F; Steinbach, C

2017-04-01

The use of nanotechnology and advanced materials promises to revolutionise many areas of technology and improve our daily life. In that respect, many positive effects on the environment are expected, either directly, by developing new technologies for remediation, filtering techniques or energy generation, or indirectly, by e.g. saving resources due to lower consumption of raw materials, or lower energy and fuel consumption due to reduced weight of vehicles. However, such beneficial effects of new technologies are often confronted by concerns regarding the safety of novel substances or materials. During the past 10 years, great effort has been put into research on potential hazards of nanomaterials towards environmental organisms. As the methodology for reliable assessment of nanomaterials was immature, many studies reporting contradictory results have been published, hindering both risk assessment for nanomaterials, as well as the knowledge communication to all involved stakeholders. Thus, DaNa 2.0 serves as a platform to implement trusted knowledge on nanomaterials for an objective discussion.
Assessment of computer techniques for processing digital LANDSAT MSS data for lithological discrimination of Serra do Ramalho, State of Bahia

NASA Technical Reports Server (NTRS)

Paradella, W. R. (Principal Investigator); Vitorello, I.; Monteiro, M. D.

1984-01-01

Enhancement techniques and thematic classifications were applied to the metasediments of Bambui Super Group (Upper Proterozoic) in the Region of Serra do Ramalho, SW of the state of Bahia. Linear contrast stretch, band-ratios with contrast stretch, and color-composites allow lithological discriminations. The effects of human activities and of vegetation cover mask and limit, in several ways, the lithological discrimination with digital MSS data. Principal component images and color composite of linear contrast stretch of these products, show lithological discrimination through tonal gradations. This set of products allows the delineations of several metasedimentary sequences to a level superior to reconnaissance mapping. Supervised (maximum likelihood classifier) and nonsupervised (K-Means classifier) classification of the limestone sequence, host to fluorite mineralization show satisfactory results.
The H,K-ATPase beta-subunit can act as a surrogate for the beta-subunit of Na,K-pumps.

PubMed

Horisberger, J D; Jaunin, P; Reuben, M A; Lasater, L S; Chow, D C; Forte, J G; Sachs, G; Rossier, B C; Geering, K

1991-10-15

Na,K-ATPase and H,K-ATPase are the only members of the P-type ATPases in which a glycosylated beta-subunit is part of the purified active enzyme. In this study, we have followed the synthesis and the posttranslational processing of the beta-subunit of H,K-ATPase (beta HK) in Xenopus oocytes injected with beta HK cRNA and have tested whether it can act as a surrogate for the beta-subunit of Na,K-ATPase (beta NaK) to support the functional expression of Na,K-pumps. In Xenopus oocytes, beta HK is processed from an Endo H-sensitive 51-kDa coreglycosylated form to an Endo H-resistant 71-kDa fully glycosylated form. Similar to beta NaK, beta HK can stabilize and increase the trypsin resistance of alpha-subunits of Na,K-ATPase (alpha NaK). Finally, expression of beta HK together with alpha NaK leads to an increased number of ouabain binding sites at the plasma membrane accompanied by an increased Rb+ uptake and Na,K-pump current. Our data suggest that beta HK, similar to beta NaK, can assemble to alpha NaK, support the structural maturation and the intracellular transport of catalytic alpha NaK, and ultimately form active alpha NaK-beta HK complexes with Na,K-pump transport properties.
Respostas religiosas à aids no Brasil: impressões de pesquisa acerca da Pastoral de DST/Aids da Igreja Católica1

PubMed Central

Seffner, Fernando; Silva, Cristiane Gonçalves Meireles da; Maksud, Ívia; Garcia, Jonathan; Rios, Luís Felipe; Natividade, Marcelo; Borges, Priscila Rodrigues; Parker, Richard; Terto, Veriano

2009-01-01

O texto encontra-se estruturado em quatro partes. Na primeira delas, apresentamos um conjunto de considerações e informações acerca da situação da aids no Brasil, das relações entre religião, sexualidade, aids e estado laico, bem como uma descrição mais clara do Projeto Respostas Religiosas ao HIV/Aids no Brasil, do qual este texto apresenta algumas impressões de pesquisa preliminares. A seguir, dedicamos um item a apresentação da Pastoral de DST/Aids, sua história, estrutura e objetivos. No item seguinte problematizamos diversas questões em particular no âmbito das relações Estado e Igreja, relações entre agentes de pastoral e hierarquia da Igreja, e questões ligadas mais diretamente à sexualidade e aids, todas referenciadas ao trabalho da Pastoral de DST/Aids. Ao final, apresentamos a bibliografia e fontes consultadas. PMID:20442806
Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay.

PubMed

Kasar, Sharayu; Kumar, Sumit; Bajpai, R K; Tomar, B S

2016-01-01

Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay, proposed as a backfill material in the Indian geological repository, was studied using the out-diffusion method. Radiotracers (22)Na, (137)Cs, (85)Sr and (154)Eu were used; the first three are carrier-free enabling experimental work at sub-micromolar metal ion concentration, and Eu(III) tracer (154)Eu was used at sub millimolar concentration. An out-diffusion methodology, wherein a thin planar source of radioactivity placed between two clay columns diffuses out, was used to obtain the apparent diffusion coefficient (Da) values. This methodology enabled determination of diffusion coefficient even for strongly sorbing (154)Eu. Da values for (22)Na, (137)Cs, (85)Sr and (154)Eu were 2.35 (±0.14) × 10(-11), 2.65 (±0.09) × 10(-12), 3.32 (±0.15) × 10(-11) and 1.23 (±0.15) × 10(-13) m(2) s(-1), respectively. Da values were found to be in fair agreement with literature data reported for similar mineralogical sediments. Sorption of radionuclides on the clay was also determined in the present study and differences in Da values were rationalized on the basis of sorption data. Distribution ratios (Kd) for Cs(I) and Eu(III) were higher than that for Sr(II), which in turn was higher than that for Na(I). Copyright © 2015 Elsevier Ltd. All rights reserved.
Tão perto de casa, tão longe de nós: etnografia das novas margens no centro da urbe

PubMed Central

Fernandes, Por Luís

2011-01-01

Philippe Bourgois é, desde 2007, “Richard Perry University professor” no Departamento de Antropologia e de Medicina Familiar e de Práticas Comunitárias na Universidade da Pensilvânia. Esteve durante largos anos ligado ao Departamento de Antropologia, História e Medicina Social da Universidade da Califórnia, São Francisco. A publicação, em 1995, de In Search of Respect: Selling Crack in El Barrio1 projectaria o seu nome muito para além dos Estados Unidos: uma etnografia no coração porto-riquenho do Harlem, em torno dos actores e dos ambientes da venda de crack. Seguir-se-ia um longo trabalho de terreno em acampamentos de dependentes de heroína em São Francisco, orientando o seu trabalho para as formas mais radicais da pobreza e da marginalidade nos EUA. É deste trabalho de terreno que sai o seu último livro, Righteous Dopefiend2. Em Junho de 2007 esteve em Lisboa para participar na 3.a edição do “Ethnografeast”. Foi então que aproveitámos a oportunidade para ouvir um percurso invulgar contado pelo próprio: uma longa conversa no Hotel Zurique, cujo nome só vem ao caso por evocar o país onde passou uma parte da infância. PMID:22013286
A distância e o conteúdo estelar da região HII gigante G333.1-0.4 - vínculos para a taxa de formação estelar da galáxia

NASA Astrophysics Data System (ADS)

Figuerêdo, E.; Damineli, A.; Blum, R.; Conti, P.

2003-08-01

Neste trabalho apresentamos imagens de alta resolução angular da região HII gigante G333.1-0.4 obtidas através dos filtros J, H e K no telescópio de 4-m do CTIO. Este trabalho faz parte de um estudo de regiões HII gigantes no infravermelho próximo que tem por objetivo estudar a natureza da formação de estrelas massivas e traçar a estrutura espiral de nossa galáxia. Nossa determinação da distância é baseada no método da paralaxe espectroscópica de estrelas OB localizadas na seqüência principal de idade zero (ZAMS) do Diagrama HR. No caso de G333.1-0.4, a magnitude aparente das estrelas localizadas na ZAMS indica que a distância não pode ser maior do que o limite inferior determinado por técnica rádio (2,8 kpc). Resultados semelhantes foram encontrados para regiões estudadas anteriormente, reforçando a idéia de que a taxa de formação estelar na Via Láctea é menor do que o determinado a partir de dados rádio. Nossos resultados mais recentes sobre o conteúdo estelar de G333.1-0.4 revelaram vários objetos que possuem cores bastante avermelhadas (H-K > 2,0). Nós identificamos estes objetos usando os diagramas cor-cor e cor-magnitude dos aglomerados. Estes objetos apresentam um forte excesso em emissão na banda K e possivelmente se tratam de estrelas do tipo OB envolvidas por um disco/envelope circumestelar espesso. O estudo da função de massa inical desta região, em conjunto com resultados de nossos trabalhos anteriores, aponta para uma IMF independente da posição galática. A contagem de estrelas nos fornece um valor para o número de fótons no contínuo de Lyman que corrobora com a afirmação de que G333.1-0.4 se encontra mais próxima da menor distância determinada por rádio.
MtDNA diversity among four Portuguese autochthonous dog breeds: a fine-scale characterisation

PubMed Central

van Asch, Barbara; Pereira, Luísa; Pereira, Filipe; Santa-Rita, Pedro; Lima, Manuela; Amorim, António

2005-01-01

Background The picture of dog mtDNA diversity, as obtained from geographically wide samplings but from a small number of individuals per region or breed, has revealed weak geographic correlation and high degree of haplotype sharing between very distant breeds. We aimed at a more detailed picture through extensive sampling (n = 143) of four Portuguese autochthonous breeds – Castro Laboreiro Dog, Serra da Estrela Mountain Dog, Portuguese Sheepdog and Azores Cattle Dog-and comparatively reanalysing published worldwide data. Results Fifteen haplotypes belonging to four major haplogroups were found in these breeds, of which five are newly reported. The Castro Laboreiro Dog presented a 95% frequency of a new A haplotype, while all other breeds contained a diverse pool of existing lineages. The Serra da Estrela Mountain Dog, the most heterogeneous of the four Portuguese breeds, shared haplotypes with the other mainland breeds, while Azores Cattle Dog shared no haplotypes with the other Portuguese breeds. A review of mtDNA haplotypes in dogs across the world revealed that: (a) breeds tend to display haplotypes belonging to different haplogroups; (b) haplogroup A is present in all breeds, and even uncommon haplogroups are highly dispersed among breeds and continental areas; (c) haplotype sharing between breeds of the same region is lower than between breeds of different regions and (d) genetic distances between breeds do not correlate with geography. Conclusion MtDNA haplotype sharing occurred between Serra da Estrela Mountain dogs (with putative origin in the centre of Portugal) and two breeds in the north and south of the country-with the Castro Laboreiro Dog (which behaves, at the mtDNA level, as a sub-sample of the Serra da Estrela Mountain Dog) and the southern Portuguese Sheepdog. In contrast, the Azores Cattle Dog did not share any haplotypes with the other Portuguese breeds, but with dogs sampled in Northern Europe. This suggested that the Azores Cattle Dog
Geochemical and isotopic constraints on the tectonic setting of Serra dos Carajas belt, eastern Para, Brazil

NASA Technical Reports Server (NTRS)

Olszewski, W. J., Jr.; Gibbs, A. K.; Wirth, K. R.

1986-01-01

The lower part of the Serra dos Carajas belt is the metavolcanic and metasedimentary Grao para Group (GPG). The GPG is thought to unconformably overlie the older (but undated) Xingu Complex, composed of medium and high-grade gneisses and amphibolite and greenstone belts. The geochemical data indicate that the GPG has many features in common with ancient and modern volcanic suites erupted through continental crust. The mafic rocks clearly differ from those of most Archean greenstone belts, and modern MORB, IAB, and hot-spot basalts. The geological, geochemical, and isotopic data are all consistent with deposition on continental crust, presumably in a marine basin formed by crustal extension. The isotopic data also suggest the existence of depleted mantle as a source for the parent magmas of the GPG. The overall results suggest a tectonic environment, igneous sources, and petrogenesis similar to many modern continental extensional basins, in contrast to most Archean greenstone belts. The Hammersley basin in Australia and the circum-Superior belts in Canada may be suitable Archean and Proterozoic analogues, respectively.
Linking Community Communication to Conservation of the Maned Wolf in Central Brazil

ERIC Educational Resources Information Center

Bizerril, Marcelo Ximenes A.; Soares, Carla Cruz; Santos, Jean Pierre

2011-01-01

This article describes the environmental education (EE) program developed in the neighboring community of Serra da Canastra National Park based on a research project focused on the maned wolf conservation. The article assesses three tools used to foster the community's participation in discussing local issues: (1) communal production of a book…
La Serra d'Almos (Tarragona): an example of phenological data rescue and preservation in Catalonia

NASA Astrophysics Data System (ADS)

Busto, Montserrat; Cunillera, Jordi; de Yzaguirre, Xavi; Borrell, Josep

2016-04-01

The interruption of important phenological series and the progressive disappearance of phenological observations in Catalonia led the Meteorological Service of Catalonia (SMC) to design and impulse a new phenological network promoted by the Climate Change Unit of this Met Service. The "Fenocat" network was born in March 2013, and currently has around fifty observers distributed throughout Catalonia that observe plants, birds and butterflies. We are providing data from different plant phenophases to PEP725 database. Besides this new phenological network (Fenocat), one of the aims of SMC is to rescue and preserve historical data from different observation points in Catalonia. We show in this poster the example of rescue and preservation of phenological data from la Serra d'Almos (in Tivissa, near Tarragona, Catalonia, NE Iberian Peninsula), an observation series that began in 1973. After digitalization process and quality control tasks, we show preliminary results of this phenological series, and we compare them with those of similar European series. We show the evolution trends for different observed species, such as almond tree (Prunus dulcis), hazel (Corylus avellana), plum (Prunus domestica), olive tree (Olea europea), apple tree (Malus domestica) or vineyard (Vitis vinifera).
Geochemical and isotopic evidence for the petrogenesis and emplacement tectonics of the Serra dos Órgãos batholith in the Ribeira belt, Rio de Janeiro, Brazil

NASA Astrophysics Data System (ADS)

Machado, Rômulo; Philipp, Ruy Paulo; McReath, Ian; Peucat, Jean Jacques

2016-07-01

The Serra dos Órgãos batholith in the State of Rio de Janeiro (Brazil) is a NE-SW-trending elongated body that occupies ca. 5000 km2 in plan view. It is a foliated intrusion, especially at its borders and is crosscut by syn-magmatic shear zones, with foliations that are moderately-to steeply-dipping to the northwest and moderately-to shallow-dipping in the center and to the southeast, in a configuration of a large laccolith. It was emplaced between 560 and 570 Ma, during an extensional episode that was part of a series of events that comprise the Brasiliano Orogeny in SE Brazil, and which includes deformation, metamorphism and granite intrusion during the interval between 630 and 480 Ma. The two main rock types in the batholith are biotite-hornblende monzogranite, and biotite leucogranite, with subordinate tonalite, granodiorite, diorite, quartz diorite (enclaves), aplite and pegmatite. Harker-type diagrams help show two rock groups with similar trends of evolution: a dioritic and a granitic. The first one is tholeiitic, whereas the second is calc-alkaline, with medium-to high-K calc-alkaline affinity and metaluminous to slightly peraluminous character. In both groups strong decrease in Al2O3, MgO, FeOT and CaO relative to silica contents are observed, which is compatible with trends of fractional crystallization involving clinopyroxene and/or hornblende, plagioclase, opaque minerals, apatite, microcline and biotite. The Sr and Nd isotopic data suggest recycling of a Paleoproterozoic crust as an important petrological process to generate the batholith rocks. Geothermometry (amphibole composition) and geobarometry (saturation in zircon and apatite) indicate that most of the batholith solidified at mid to lower crustal levels at about 750 °C and between 5 and 5.5 kbar. We consider that Serra dos Órgãos crustal protoliths underwent melting caused by the interaction with hotter mafic magma at the base of the crust. These two magmas, with distinct initial
Sobre a largura da última superfície de espalhamento

NASA Astrophysics Data System (ADS)

Nobre, M. A. S.; Pires, N.; Lima, J. A. S.

2003-08-01

De acordo com o modelo do "Big-Bang", no universo primordial a matéria estava em equilíbrio térmico com a radiação. Com a expansão a temperatura da radiação cai. Quando a temperatura chega em torno dos 4.000K, os espalhamentos diminuem, começando a recombinação dos prótons e elétrons em Hidrogênio neutro (era conhecida como da recombinação). Ao final da recombinação, os fótons se propagam livremente sofrendo, em princípio, somente os efeitos do "redshift" cosmológico. Esses fótons nos alcançam hoje como a radiação cósmica de fundo (RCF), e parecem vir de uma superfície esférica ao nosso redor, tal que o raio dela é a distância que ele viajou desde seu último espalhamento na época da recombinação. Naturalmente, esse processo não ocorreu abruptamente, implicando na existência de uma largura no espaço dos "redshifts" que deve depender do modelo cosmológico específico e dos processos físicos considerados. Neste trabalho analisamos os efeitos de diferentes modelos - a saber, aqueles com decaimento do vácuo L(t), criação de matéria, quintessência e gás de Chaplygin - sobre a última superfície de espalhamento da RCF, em particular sua largura e a função visibilidade, que determina a probabilidade de um fóton ter tido seu último espalhamento num "redshift" z. No caso particular dos modelos com decaimento do vácuo, existe uma forte dependência da função visibilidade com L(t). Tais efeitos poderão ser testados através da análise dos resultados de experimentos mais precisos que estão atualmente em andamento, como por exemplo, o WMAP.
Ventos em supergigantes B[e] das nuvens de Magalhães e da Galáxia

NASA Astrophysics Data System (ADS)

de Araújo, F. X.; Pilling, D. A.; Pereira, C. B.; Fernandes, M. B.

2003-08-01

As Supergigantes B[e] apresentam as seguintes características: (i) alta luminosidade; (ii) espectro típico de estrelas de tipo B; (iii) linhas permitidas e proibidas em emissão de metais de baixa ionização, especialmente FeII; (iv) linhas de Balmer, e por vêzes também dos ions HeI e FeII, com perfis tipo P Cygni indicativos de altas taxas de perda de massa. Atualmente estamos desenvolvendo um projeto que visa comparar as propriedades fisicas (principalmente e v¥) dos ventos destes objetos nas Nuvens de Magalhães e na Galaxia. O objetivo é estudar a influência da metalicidade. No presente painel apresentamos uma determinação das velocidades terminais de 11 estrelas, sendo 4 na GNM (Hen S111, 66, R126 e Hen S93), 4 na PNM (Hen S18, S23, S65 e R4) e 3 na Galaxia (CPD-529243, MWC 300 e GG Car). Nossos dados são espectros de alta resolução obtidos no telescópio 1.52m do ESO com o espectrógrafo FEROS. Para determinar as velocidades terminais usamos as linhas Hd e HeI 3888 Å cujas componentes em absorção costumam estar livres de "blends" e estruturas. Nossos resultados sugerem que as velocidades de expansão na GNM são maiores (ainda que apenas ligeiramente) do que aquelas da PNM, como esperado. No entanto, os objetos da Galaxia não parecem seguir a mesma tendência.
A new brachypterous genus of Brazilian stag beetle (Coleoptera: Lucanidae: Lucaninae) with description of three new species.

PubMed

Grossi, Paschoal Coelho

2016-02-09

Montesinus gen. nov. is described from Brazil, along with three new species, Montesinus monnei sp. nov. (Holotype male deposited in MNRJ: Brazil, Espírito Santo State, Parque Nacional do Caparaó, 2500 m a.s.l., 13.IV.2001, F.O. Correia leg.), M. tatula sp. nov. (Holotype female deposited in CERPE: Brazil, Minas Gerais State, Corinto, 900 m a.s.l., I.1998, E. Antunes leg.), and M. machadoi sp. nov. (Holotype female deposited in MNRJ: Brazil, Espírito Santo State, Serra do Caparaó, Ibitirama, 2600 m a.s.l., 10-12.IV.2012, M.V.P. Simões leg.). This unusual genus is related to Altitatiayus Weinreich, with which it shares the brachypterous condition and also some characters of the male genitalia, being distinguished from it mainly by its punctate flat head and indistinct elytral striae. The three new species are distinguished by their general color, shape of posterior margin of pronotum, tibial armature and elytral punctures. The new species are from two isolated mountain formations, called Serra do Caparaó and Serra do Espinhaço formations. This is the third brachypterous genus of stag beetle found in Brazil, but it occurs in mountains isolated from the Serra da Mantiqueira where the other two genera are found. The habitus, male genitalia and maxillae of the new species are illustrated.
Católicos, fidelidade conjugal e AIDS: entre a cruz da doutrina moral e as espadas do cotidiano sexual dos adeptos1

PubMed Central

Rios, Luis Felipe; de Aquino, Francisca Luciana; Muñoz-Laboy, Miguel; Oliveira, Cinthia; Parker, Richard

2009-01-01

Neste artigo discutimos a visão da Igreja Católica sobre sexualidade na interface com a epidemia do HIV/AIDS. Nossa reflexão está embasada em pesquisa etnográfica que envolveu dois meses de observação participante do cotidiano de católicos de um bairro popular da Região Metropolitana do Recife, além de contar com entrevistas a onze dos leigos engajados nos serviços religiosos da igreja do bairro e a oito sacerdotes que realizam seus trabalhos religiosos em outras localidades. Nelas abordamos diferentes temáticas relacionadas ao enfrentamento da epidemia da AIDS. Nesse contexto, conjugalidade e fidelidade se afiguram como importantes analisadores de como aqueles lidam com a epidemia, em uma variedade de re-descrições práticas e de re-interpretações conceptuais das assertivas do discurso moral religioso – ainda que, muitos impasses permaneçam em aberto em termos das prerrogativas da Igreja e seus possíveis rebatimentos na saúde sexual dos adeptos. PMID:21765650
Mesoproterozoic rapakivi granites of the Rondonia Tin Province, southwestern border of the Amazonian craton, Brazil-I. Reconnaissance U-Pb geochronology and regional implications

USGS Publications Warehouse

Bettencourt, Jorge S.; Tosdal, R.M.; Leite, W.B.; Payolla, B.L.

1999-01-01

Rapakivi granites and associated mafic and ultramafic rocks in the Rondonia Tin Province, southwestern Amazonian craton, Brazil were emplaced during six discrete episodes of magmatism between ca 1600 and 970 Ma. The seven rapakivi granite suites emplaced at this time were the Serra da Providencia Intrusive Suite (U-Pb ages between 1606 and 1532 Ma); Santo Antonio Intrusive Suite (U-Pb age 1406 Ma); Teotonio Intrusive Suite (U-Pb age 1387 Ma); Alto Candeias Intrusive Suite (U-Pb ages between 1346 and 1338 Ma); Sao Lourenco-Caripunas Intrusive Suite (U-Pb ages between 1314 and 1309 Ma); Santa Clara Intrusive Suite (U-Pb ages between 1082 and 1074 Ma); and Younger Granites of Rondonia (U-Pb ages between 998 and 974 Ma). The Serra da Providencia Intrusive Suite intruded the Paleoproterozoic (1.80 to 1.70 Ga) Rio Negro-Juruena crust whereas the other suites were emplaced into the 1.50 to 1.30 Ga Rondonia-San Ignacio crust. Their intrusion was contemporaneous with orogenic activity in other parts of the southwestern Amazonian craton, except for the oldest, Serra da Providencia Intrusive Suite. Orogenic events coeval with emplacement of the Serra da Providencia Intrusive Suite are not clearly recognized in the region. The Santo Antonio, Teotonio, Alto Candeias and Sao Lourenco-Caripunas Intrusive Suites are interpreted to represent extensional anorogenic magmatism associated with the terminal stages of the Rondonian-San Ignacio orogeny. At least the Sao Lourenco-Caripunas rapakivi granites and coeval intra-continental rift sedimentary rocks may, in contrast, represent the products of extensional tectonics and rifting preceding the Sunsas/Aguapei orogeny (1.25 to 1.0 Ga). The two youngest rapakivi suites, the Santa Clara Intrusive Suite and Younger Granites of Rondonia, seemingly represent inboard magmatism in the Rondonian-San Ignacio Province during a younger episode of reworking in the Rio Negro-Juruena Province during the waning stages of the collisional 1.1 to 1.0 Ga
Estudo de não gaussianidade nas anisotropias da RCF medidas Wmap

NASA Astrophysics Data System (ADS)

Andrade, A. P. A.; Wuensche, C. A.; Ribeiro, A. L. B.

2003-08-01

A investigação do campo de flutuações da Radiação Cósmica de Fundo (RCF) pode oferecer um importante teste para os modelos cosmológicos que descrevem a origem e a evolução das flutuações primordiais. De um lado, apresenta-se o modelo inflacionário que prevê um espectro de flutuações adiabáticas distribuídas segundo uma gaussiana e, de outro, os modelos de defeitos topológicos (dentre outros) que descrevem um mecanismo para a geração de flutuações de isocurvatura que obedecem a uma distribuição não gaussiana. Este trabalho tem como objetivo caracterizar traços do modelo não gaussiano de campo misto (entre flutuações adiabáticas e de isocurvatura) nos mapas do Wilkinson Microwave Anisotropy Probe (WMAP). Simulações das anisotropias da RCF no contexto de mistura indicam traços marcantes na distribuição das flutuações de temperatura, mesmo quando consideradas pequenas contribuições do campo de isocurvatura (da ordem de 0.001). O efeito da mistura entre os campos resulta na transferência de potência de flutuações em escalas angulares intermediárias para flutuações em pequenas escalas angulares. Este efeito pode ser caracterizado pela relação entre as amplitudes dos primeiros picos acústicos no espectro de potência da RCF. Neste trabalho, investigamos a contribuição do campo de isocurvatura, no contexto de mistura, sobre as observações recentes da RCF realizadas pelo WMAP. As previsões do modelo de campo misto, uma vez confrontadas com as observações em pequenas escalas angulares, podem ajudar a revelar a natureza das flutuações primordiais.

Latest research results on the effects of nanomaterials on humans and the environment: DaNa - Knowledge Base Nanomaterials

NASA Astrophysics Data System (ADS)

Marquardt, C.; Kühnel, D.; Richter, V.; Krug, H. F.; Mathes, B.; Steinbach, C.; Nau, K.

2013-04-01

Nanotechnology is considered one of the key technologies of the 21st century. The success of this fascinating technology is based on its versatility. It will bring about fundamental changes of basic research as well as of many sectors of industry and also of daily life from electronics to the health care system. However, consumers often miss reliable and understandable information on nanomaterials and all aspects of this versatile technology. A huge body of data on the potential hazards of nanoobjects towards human and environmental health already exists, but is either not easily accessible for a broad audience or presented unprocessable for nonexperts. But risk communication is an essential and thus integral component of risk management. For that purpose, the DaNa-Project aims at filling this gap by collecting and evaluating scientific results in an interdisciplinary approach with scientists from different research areas, such as human and environmental toxicology, biology, physics, chemistry, and sociology. Research findings from the field of human and environmental nanotoxicology are being prepared and presented together with material properties and possible applications for interested laymen and stakeholders. For the evaluation of literature a "Literature Criteria Checklist" has been developed as well as a Standard Operation Procedure template (SOP) based on careful scientific practice.
Profilaxia de tromboembolismo venoso na gestação

PubMed Central

de Oliveira, André Luiz Malavasi Longo; Marques, Marcos Arêas

2016-01-01

Resumo O tromboembolismo venoso é importante causa de morbidade e mortalidade obstétrica. Durante a gestação, o risco de sua ocorrência aumenta entre cinco e dez vezes quando comparado ao de mulheres não gestantes de mesma idade. Associado a esse fato, a gestante apresenta algumas limitações para o diagnóstico clínico (alta frequência de dor e edema nos membros inferiores), ecográfico (menor sensibilidade e especificidade no diagnóstico de trombose venosa de ilíaca com a evolução da gestação) e laboratorial (o D-dímero apresenta aumento progressivo no decorrer da gravidez). Uma estratificação criteriosa de risco de tromboembolismo venoso de cada mulher antes da gestação pode diminuir a incidência dessa doença, frequente e de difícil diagnóstico na gravidez, e suas complicações. PMID:29930607
Quaternary structure and apical membrane sorting of the mammalian NaSi-1 sulfate transporter in renal cell lines.

PubMed

Regeer, Ralf R; Nicke, Annette; Markovich, Daniel

2007-01-01

NaSi-1 encodes a Na(+)-sulfate cotransporter expressed on the apical membrane of renal proximal tubular cells, which is responsible for body sulfate homeostasis. Limited information is available on NaSi-1 protein structure and the mechanisms controlling its apical membrane sorting. The aims of this study were to biochemically determine the quaternary structure of the rat NaSi-1 protein and to characterize its expression in renal epithelial cell lines. Hexahistidyl-tagged NaSi-1 (NaSi-1-His) proteins expressed in Xenopus oocytes, appeared as two bands of about 60 and 75 kDa. PNGase F treatment shifted both bands to 57 kDa while endoglycosidase H treatment led to a downward shift of the lower molecular mass band only. Mutagenesis of a putative N-glycosylation site (N591S) produced a single band that was not shifted by endoglycosidase H or PNGase F, confirming a single glycosylation site at residue 591. Blue native-PAGE and cross-linking experiments revealed dimeric complexes, suggesting the native form of NaSi-1 to be a dimer. Transient transfection of EGFP/NaSi-1 in renal epithelial cells (OK, LLC-PK1 and MDCK) demonstrated apical membrane sorting, which was insensitive to tunicamycin. Transfection of the EGFP/NaSi-1 N591S glycosylation mutant also showed apical expression, suggesting N591 is not essential for apical sorting. Treatment with cholesterol depleting compounds did not disrupt apical sorting, but brefeldin A led to misrouting to the basolateral membrane, suggesting that NaSi-1 sorting is through the ER to Golgi pathway. Our data demonstrates that NaSi-1 forms a dimeric protein which is glycosylated at N591, whose sorting to the apical membrane in renal epithelial cells is brefeldin A-sensitive and independent of lipid rafts or glycosylation.
Dating of fossil human teeth and shells from Toca do Enoque site at Serra das Confusões National Park, Brazil.

PubMed

Kinoshita, Angela; Sullasi, Henry L; Asfora, Viviane K; Azevedo, Renata L; Guzzo, Pedro; Guidon, Niede; Figueiredo, Ana Maria G; Khoury, Helen; Pessis, Anne-Marie; Baffa, Oswaldo

2016-06-07

This work reports the dating of a fossil human tooth and shell found at the archaeological site Toca do Enoque located in Serra das Confusões National Park (Piauí, Brazil). Many prehistoric paintings have been found at this site. An archaeological excavation unearthed three sepulchers with human skeletons and some shells. Two Brazilian laboratories, in Ribeirão Preto (USP) and Recife (UFPE), independently performed Electron Spin Resonance (ESR) measurements to date the tooth and the shell and obtain the equivalent dose received by each sample. The laboratories determined similar ages for the tooth and the shell (~4.8 kyBP). The results agreed with C-14 dating of the shell and other samples (charcoal) collected in the same sepulcher. Therefore, this work provides a valid inter-comparison of results by two independent ESR-dating laboratories and between two dating methods; i.e., C-14 and ESR, showing the validity of ESR dating for this range of ages.
Análise da medição do raio solar em ultravioleta

NASA Astrophysics Data System (ADS)

Saraiva, A. C. V.; Giménez de Castro, C. G.; Costa, J. E. R.; Selhorst, C. L.; Simões, P. J. A.

2003-08-01

A medição acurada do raio solar em qualquer banda do espectro eletromagnético é de relevância na formulação e calibração de modelos da estrutura e atmosfera solar. Esses modelos atribuem emissão do contínuo do Sol calmo em microondas à mesma região da linha Ha do Hell. Apresentamos a medição do raio solar em UV com imagens do EIT (Extreme Ultraviolet Image Telescope) entre 1996 e 2002, no comprimento de onda 30,9 nm (Ha do Hell), que se forma na região de transição/cromosfera solar. A técnica utilizada para o cálculo do raio UV foi baseada na transformada Wavelet B3spline. Fizemos um banco de dados com 1 imagem por dia durante o período citado. Obtivemos como resultado o raio médio da ordem de 975.61" e uma diminuição do mesmo para o período citado variando em média -0,45" /ano. Comparamos estes dados com os valores obtidos pelo ROI (Radio Observatório de Itapetinga) em 22/48 GHz e Nobeyama Radio Heliograph em 17 GHz mostrando que os raios médios são muito próximos o que indica que a região de formação nessas freqüências é a mesma conforme os modelos. Comparamos os resultados também com outros índices de atividade solar.
Detecção da fase impulsiva de uma explosão solar gigante até 405 GHz

NASA Astrophysics Data System (ADS)

Raulin, J.-P.; Makhmutov, V.; Kaufmann, P.; Pacini, A. A.; Luethi, T.; Hudson, H. S.; Gary, D. E.; Yoshimori, M.

2003-08-01

A explosão ocorrida no dia 25/08/2001 foi uma das mais intensas do presente ciclo solar em ondas de rádio de altas frequências. Foram medidas em ondas milimétricas e submilimétricas, aproximadamente, 105 e vários milhares de unidades de fluxo solar, respectivamente. Apresentamos um estudo deste evento em múltiplas frequências, desde microondas (1GHz), até ondas submilimétricas (405 GHz) detectadas pelo Telescópio Solar para ondas Submilimétricas (SST). Esta base de dados foi complementada utilizando-se o experimento Yohkoh, incluindo a emissão em raios-X duros e raios-g (até 100 MeV), e imagens em raios-X moles da região ativa envolvida. Enfocamos e discutimos principalmente os seguintes aspectos da fase impulsiva do evento: (i) as implicações deduzidas do espectro eletromagnético, obtido pela primeira vez até 405 GHz; (ii) a dinâmica da região ativa. Os resultados mostram que para explicar o espectro rádio observado, são necessários entre 3.5×1037 e 1.5×1039 elétrons acelerados acima de 20 keV em uma região de campo magnético entre 300 e 800 Gauss. A estimativa do fluxo de fótons que seria produzido por estes elétrons, mostra que grande parte deles não precipitou na baixa atmosfera. A evolução temporal da emissão em raios-X moles revela que a configuração magnética da região ativa foi muito dinâmica durante a fase impulsiva da explosão. Em particular, mostramos que a produção dos elétrons altamente energéticos foi iniciada junto com a aparição, na baixa coroa solar, de um novo sistema compacto de estruturas magnéticas. Este fato sugere que os locais de aceleração estão localizados na baixa atmosfera do Sol, como resultado da interação entre o novo sistema compacto e o campo magnético ambiente da região ativa.
Gastrointestinal parasites among felids inhabiting the Serra dos Órgãos National Park, Rio de Janeiro, Brazil.

PubMed

Dib, Laís Verdan; Cronemberger, Cecília; Pereira, Fabiane de Aguiar; Bolais, Paula Forain; Uchôa, Claudia Maria Antunes; Bastos, Otilio Machado Pereira; Amendoeira, Maria Regina Reis; Barbosa, Alynne da Silva

2018-05-24

This study aimed to investigate the species of felids that inhabit the Serra dos Órgãos National Park (Parnaso) and gastrointestinal parasites at various stages of their life cycles in the feces of these animals. Between 2013 and 2015, felid feces were collected from trails in Parnaso. The sampling points were georeferenced. A total of 82 fecal samples were processed, of which 79 were collected on the ground, two from captured felids and one from a necropsied animal. All samples underwent coproparasitological techniques. Samples collected from the environment underwent additional trichological analysis. Fur patterns corresponding to Leopardus guttulus, Leopardus pardalis, Leopardus wiedii and Puma yagouaroundi were observed in 32 of the samples collected on the soil. High frequency of potentially parasitic evolving forms (88.6%) was observed in felid feces, particularly eggs of the family Diphyllobothriidae (68.6%). Besides, were also detected, eggs of superfamily Ascaridoidea (42.9%), nematode larvae (28.6%), eggs of order Strongylida (28.6%), Capillaria sp. (8.6%), Trichuris sp. (8.6%), eggs of order Spirurida (2.9%), unsporulated coccidian oocysts (8.6%) and Eimeria sp. (2.9%). Felid feces presented higher frequency of polyparasitism (60%) than monoparasitism (28.6%).
Three new species of mealybug (Hemiptera, Coccomorpha, Pseudococcidae) on persimmon fruit trees (Diospyros kaki) in southern Brazil.

PubMed

Pacheco da Silva, Vitor C; Kaydan, Mehmet Bora; Germain, Jean-François; Malausa, Thibaut; Botton, Marcos

2016-01-01

Brazil has the greatest insect diversity in the world; however, little is known about its scale insect species (Hemiptera: Coccomorpha). Mealybugs (Pseudococcidae) have been found in at least 50% of persimmon orchards Diospyros kaki L. in the southern part of the country. In this study three new mealybug species on persimmon trees located in the Serra Gaúcha Region, RS, Brazil, namely, Anisococcus granarae Pacheco da Silva & Kaydan, sp. n., Ferrisia kaki Kaydan & Pacheco da Silva, sp. n. and Pseudococcus rosangelae Pacheco da Silva & Kaydan, sp. n. are described. In addition, an identification key for the genera occurring on fruit orchards and vineyards in Brazil is provided, together with illustrations and molecular data for the new species.
Morphology and morphometry of upland lakes over lateritic crust, Serra dos Carajás, southeastern Amazon region.

PubMed

Silva, Marcio S DA; Guimarães, José T F; Souza Filho, Pedro W M; Nascimento Júnior, Wilson; Sahoo, Prafulla K; Costa, Francisco R DA; Silva Júnior, Renato O; Rodrigues, Tarcísio M; Costa, Marlene F DA

2018-01-01

High-resolution satellite images, digital elevation models, bathymetric and sedimentological surveys coupled with statistical analysis were used to understand the physical environment and discuss their influence on water quality of the five upland lakes of Serra Sul dos Carajás, southeast Amazonia. The lakes have mid-altitude ranges (elevation), very small (catchment) and shallow to very shallow (central basins). Based on the length, area and volume, Violão and TI (Três Irmãs)-3 lakes may present large vertical movements of the water due to wind action and weakly stratified waters. Trophic conditions based on depth and shore development (Ld) parameters must be used with caution, since Amendoim Lake is relatively deep, but it is oligotrophic to ultra-oligotrophic. Ld values suggest that the lakes are circular to subcircular and are likely formed by solution process, as also suggested by volume development. TI-2 Lake is only presenting convex central basin and has highest dynamic ratio (DR), thus it may have high sedimentation and erosion rates. Based on the relationship between studied parameters, morphometric index and DR likely influence temperature and dissolved oxygen of waters of TI-2 Lake due to its depth profile and wind-induced surface mixing. Nevertheless, water quality parameters are controlled by catchment characteristics of the lakes.
Astronomy at School: Measurements of the Earth-Moon Distance. (Spanish Title: Astronomía en la Escuela: Medición de la Distancia Tierra-Luna.) Astronomia na Escola: Medida da Distância Terra-Lua

NASA Astrophysics Data System (ADS)

Paolantonio, Santiago; Pintado, Olga I.

2006-12-01

The aim of this project is to approach High School students to Science. We propose to measure the Earth-Moon distance using the parallax. The observation and measurements techniques and all the calculations needed are described in this paper. The results obtained in a test experience realized during 2003 are presented. This test shows that this is a feasible project and also shows which things needed to be improved. Se plantea la propuesta de un proyecto educativo dirigido al Nivel Medio de enseñanza, consistente en la determinación de la distancia Tierra - Luna por paralaje. Se describen las técnicas de observación, mediciones y cálculos. Se proporcionan a continuación los resultados obtenidos en la experiencia piloto realizada en el 2003, la que permitió comprobar la factibilidad de llevar a cabo la propuesta, así como perfeccionar los diferentes aspectos involucrados en la misma. Propomos neste trabalho um projeto educativo dirigido ao Ensino Médio que consiste na determinação da distância Terra-Lua pelo efeito da paralaxe. As técnicas de observação, medidas e cálculos auxiliares são descritos, e os resultados obtidos numa experiência-teste realizada no ano de 2003 apresentados. Este último teste permitiu comprovar a viabilidade de execução da proposta e aperfeiçoar diversos aspectos da mesma.
Como os Alunos do Ensino Médio da Rede Estadual de São Paulo obtém Conhecimentos Astronômicos?

NASA Astrophysics Data System (ADS)

da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

2005-08-01

Atualmente vivencia-se um mundo globalizado onde os computadores e a internet permitiram um acesso rápido e seguro a todo tipo de informação e conhecimento. O presente trabalho visa analisar a maneira pela qual alunos de segundo grau da rede estadual da cidade de São Paulo obtiveram, caso tenham, conhecimentos básicos de astronomia quanto aos fenômenos celestes que os rodeiam, tais como a sucessão dos dias e das estações do ano, além de questioná~los sobre fatos genéricos tais como: o que vem a ser o Sol, o Big Bang, o que ocasionou a extinção dos dinossauros. Para tanto foi elaborado um formulário constando de questões de múltipla escolha, o qual foi aplicado no primeiro colegial diurno da Escola Estadual Guilherme de Almeida. Num espaço amostral de 44 alunos constatou-se que 41% dos alunos adquiriram seus conhecimentos astronômicos na escola e 59% através da mídia em geral. Neste mesmo espaço amostral apenas 11% dos alunos usaram computadores na escola, 41% na residência, 5% no trabalho e 43% não utilizaram. O presente estudo revelou também que para 50% dos alunos o professor jamais utilizou um programa de computador a respeito de astronomia ou fez alguma apresentação sobre o tema. Embora em sua fase inicial este estudo revela claramente que a maioria dos alunos não obtém na escola seus conhecimentos astronômicos, estes provém de fontes não especificamente didático-pedagógicas tais como filmes e revistas populares que não raramente geram conhecimentos incompletos e em muitos casos inclusive falhos.
Desenvolvimento de modelo clínico para predição da possibilidade de identificação da artéria de Adamkiewicz por angiotomografia

PubMed Central

Amato, Alexandre Campos Moraes; Parga, José Rodrigues; Stolf, Noedir Antônio Groppo

2018-01-01

Resumo Contexto Diferenças morfológicas da artéria de Adamkiewicz (AKA) entre a população portadora e não portadora de doença aórtica têm importância clínica, influenciando as complicações neuroisquêmicas da medula espinhal em procedimentos operatórios. Ainda não é conhecida a correlação entre parâmetros clínicos e a previsibilidade da identificação dessa artéria pela angiotomografia. Objetivo Desenvolver um modelo matemático que, através de parâmetros clínicos correlacionados com aterosclerose, possa prever a probabilidade de identificação da AKA em pacientes submetidos a angiotomografias. Método Estudo observacional transversal utilizando banco de imagens e dados de pacientes. Foi feita análise estatística multivariada e criado modelo matemático logit de predição para identificação da AKA. Variáveis significativas foram utilizadas na montagem da fórmula para cálculo da probabilidade de identificação. O modelo foi calibrado, e a discriminação foi avaliada pela curva receiver operating characteristic (ROC). A seleção das variáveis explanatórias foi guiada pela maior área na curva ROC (p = 0,041) e pela significância combinada das variáveis. Resultados Foram avaliados 110 casos (54,5% do sexo masculino, com idade média de 60,97 anos e etnia com coeficiente B -2,471, M -1,297, N -0,971), com AKA identificada em 60,9%. Índice de massa corporal: 27,06 ± 0,98 (coef. -0,101); fumantes: 55,5% (coef. -1,614/-1,439); diabéticos: 13,6%; hipertensos: 65,5% (coef. -1,469); dislipidêmicos: 58,2%; aneurisma aórtico: 38,2%; dissecção aórtica: 12,7%; e trombo mural: 24,5%. Constante de 6,262. Fórmula para cálculo da probabilidade de detecção: (e−(Coef. Etnia+(Coef. IMC×IMC)+Coef.fumante+Coef.HAS+Coef.dislip+Constante)+1)−1 . O modelo de predição foi criado e disponibilizado no link https://vascular.pro/aka-model . Conclusão Com as covariáveis etnia, índice de massa corporal, tabagismo, hipertens
Profilaxia da trombose venosa profunda em cirurgia bariátrica: estudo comparativo com doses diferentes de heparina de baixo peso molecular

PubMed Central

Goslan, Carlos José; Baretta, Giórgio Alfredo Pedroso; de Souza, Hemuara Grasiela Pestana; Orsi, Bruna Zanin; Zanoni, Esdras Camargo A.; Lopes, Marco Antonio Gimenez; Engelhorn, Carlos Alberto

2018-01-01

Resumo Contexto A cirurgia bariátrica é considerada a melhor opção para o tratamento da obesidade, cujos pacientes são considerados de alto risco para fenômenos tromboembólicos. Objetivos Comparar o uso de doses diferentes de heparina de baixo peso molecular (HBPM) na profilaxia da trombose venosa profunda (TVP) em pacientes candidatos à cirurgia bariátrica em relação ao risco de TVP, alteração na dosagem do fator anti-Xa e sangramento pré ou pós-operatório. Métodos Estudo comparativo transversal em pacientes submetidos à cirurgia bariátrica distribuídos em dois grupos, que receberam doses de HBPM de 40 mg (grupo controle, GC) e 80 mg (grupo de estudo, GE). Foram avaliados por ultrassonografia vascular e dosagem de KPTT, TAP, plaquetas e fator anti-Xa. Resultados Foram avaliados 60 pacientes, sendo 34 no GC e 26 no GE. Foi observada diferença significativa somente no peso (p = 0,003) e índice de massa corporal (p = 0,018) no GE em relação ao GC. Não houve diferença na dosagem de KPTT, TAP, plaquetas e fator anti-Xa entre os grupos. Não foram detectados TVP ou sangramentos significativos em ambos os grupos. Conclusões Não houve diferença estatisticamente significativa na utilização de doses maiores de HBPM na profilaxia da TVP em pacientes candidatos à cirurgia bariátrica em relação ao risco de TVP, dosagem do fator anti-Xa e sangramento pré ou pós-operatório.
A Utilização da Astronomia como Tema Interdisciplinar e Aplicações de Objetos de Aprendizagem

NASA Astrophysics Data System (ADS)

da Silva, L. A.; Voelzke, M. R.

2008-09-01

Este trabalho visa analisar a possibilidade de relacionar conteúdos aplicados no ensino fundamental e médio de forma interdisciplinar por intermédio da astronomia, com a intervenção de objetos de aprendizagem que possam integrar as disciplinas e a utilização de recursos tecnológicos. Em uma pesquisa prévia com 20 professores de uma escola estadual situada na cidade de Guarulhos foi observado que apenas 25% dos professores utilizam algum recurso tecnológico para o desenvolvimento de conteúdos pertinentes à sua disciplina, tais como sites e softwares educativos, sendo que a maioria absoluta continua ensinando apenas com livros didáticos. A maior parte dos professores apresenta dificuldades em trabalhar sua disciplina de forma interdisciplinar, ou seja, 75% dos professores preferem aplicar os conteúdos seguindo uma hierarquia linear de tópicos, evitando a discussão de temas que de alguma forma estão relacionados. A astronomia pode vir à fascinar o ser humano e despertar sua curiosidade promovendo um maior interesse no aprendizado, podendo favorecer análises interdisciplinares de forma lógica e objetiva, desta forma colocar a astronomia como tema motivador interdisciplinar, pode ser relevante no que se refere ao distanciamento da fragmentação dos conteúdos. No Estado de São Paulo, a implantação da proposta curricular no ensino fundamental e médio mostra claramente a inserção da astronomia na maior parte das séries, principalmente na 6Âª série em que todo o bimestre se fala de astronomia.
Centro de Divulgação da Astronomia - o Observatório de São Carlos

NASA Astrophysics Data System (ADS)

Dias, W. S.; Hönel, J.; Líbero, V. L.; Anderlini, A.; de Andrade, D.; Scatena, E.; Lazo, M. J.; Trevisan, M.; de Castro, V.

2005-07-01

Apresentamos as principais características do Centro de Divulgação da Astronomia, que é constituído e um observatório cujo objetivo é a divulgação da Astronomia junto à comunidade, através de palestras e de observação direta dos astros. Descrevemos, neste trabalho, as atividades desenvolvidas desde sua fundação em 1986, e mostramos sua importância na região através de números anuais das atividades realizadas.
Three new species of mealybug (Hemiptera, Coccomorpha, Pseudococcidae) on persimmon fruit trees (Diospyros kaki) in southern Brazil

PubMed Central

Pacheco da Silva, Vitor C.; Kaydan, Mehmet Bora; Germain, Jean-François; Malausa, Thibaut; Botton, Marcos

2016-01-01

Abstract Brazil has the greatest insect diversity in the world; however, little is known about its scale insect species (Hemiptera: Coccomorpha). Mealybugs (Pseudococcidae) have been found in at least 50% of persimmon orchards Diospyros kaki L. in the southern part of the country. In this study three new mealybug species on persimmon trees located in the Serra Gaúcha Region, RS, Brazil, namely, Anisococcus granarae Pacheco da Silva & Kaydan, sp. n., Ferrisia kaki Kaydan & Pacheco da Silva, sp. n. and Pseudococcus rosangelae Pacheco da Silva & Kaydan, sp. n. are described. In addition, an identification key for the genera occurring on fruit orchards and vineyards in Brazil is provided, together with illustrations and molecular data for the new species. PMID:27199595
Gill Na+-K+-2Cl- cotransporter abundance and location in Atlantic salmon: Effects of seawater and smolting

USGS Publications Warehouse

Pelis, Ryan M.; Zydlewski, Joseph D.; McCormick, Stephen D.

2001-01-01

Na+-K+-2Cl−cotransporter abundance and location was examined in the gills of Atlantic salmon (Salmo salar) during seawater acclimation and smolting. Western blots revealed three bands centered at 285, 160, and 120 kDa. The Na+-K+-2Cl−cotransporter was colocalized with Na+-K+-ATPase to chloride cells on both the primary filament and secondary lamellae. Parr acclimated to 30 parts per thousand seawater had increased gill Na+-K+-2Cl− cotransporter abundance, large and numerous Na+-K+-2Cl− cotransporter immunoreactive chloride cells on the primary filament, and reduced numbers on the secondary lamellae. Gill Na+-K+-2Cl− cotransporter levels were low in presmolts (February) and increased 3.3-fold in smolts (May), coincident with elevated seawater tolerance. Cotransporter levels decreased below presmolt values in postsmolts in freshwater (June). The size and number of immunoreactive chloride cells on the primary filament increased threefold during smolting and decreased in postsmolts. Gill Na+-K+-ATPase activity and Na+-K+-2Cl− cotransporter abundance increased in parallel during both seawater acclimation and smolting. These data indicate a direct role of the Na+-K+-2Cl− cotransporter in salt secretion by gill chloride cells of teleost fish.
Amino acid catabolism and generation of volatiles by lactic acid bacteria.

PubMed

Tavaria, F K; Dahl, S; Carballo, F J; Malcata, F X

2002-10-01

Twelve isolates of lactic acid bacteria, belonging to the Lactobacillus, Lactococcus, Leuconostoc, and Enterococcus genera, were previously isolated from 180-d-old Serra da Estrela cheese, a traditional Portuguese cheese manufactured from raw milk and coagulated with a plant rennet. These isolates were subsequently tested for their ability to catabolize free amino acids, when incubated independently with each amino acid in free form or with a mixture thereof. Attempts were made in both situations to correlate the rates of free amino acid uptake with the numbers of viable cells. When incubated individually, leucine, valine, glycine, aspartic acid, serine, threonine, lysine, glutamic acid, and alanine were degraded by all strains considered; arginine tended to build up, probably because of transamination of other amino acids. When incubated together, the degradation of free amino acids by each strain was dependent on pH (with an optimum pH around 6.0). The volatiles detected in ripened Serra da Estrela cheese originated mainly from leucine, phenylalanine, alanine, and valine, whereas in vitro they originated mainly from valine, phenylalanine, serine, leucine, alanine, and threonine. The wild strains tested offer a great potential for flavor generation, which might justify their inclusion in a tentative starter/nonstarter culture for that and similar cheeses.
Avaliação dos efeitos do subgalato de bismuto na proliferação de miofibroblastos

PubMed Central

de Lima, Rubianne Ligório; Sampaio, Cláudia Paraguaçu; Seidel, Karin Caroline; Branco, Melina; Sobreiro, Rafaela Mabile

2016-01-01

Resumo Contexto O subgalato de bismuto é um metal pesado e insolúvel, utilizado por suas propriedades adstringentes e hemostáticas. Objetivo Avaliar os efeitos do subgalato de bismuto na cicatrização mediante observação de miofibroblastos em pele de ratos. Métodos Foram utilizados 60 ratos da linhagem Wistar, que receberam uma ferida no dorso da pele. Os animais foram divididos em dois grupos: controle (aplicação diária de cloreto de sódio a 0,9%) e experimental (aplicação diária de 0,5 mg de subgalato de bismuto). Cada grupo foi subdividido em três subgrupos, que foram reoperados para retirada da ferida em 3, 7 e 14 dias. Foi realizada coloração de hematoxilina eosina, picrosirius e imuno-histoquímica para avaliar contagem de miofibroblastos, resposta inflamatória e síntese de colágeno. Resultados Não foi encontrada diferença entre os grupos controle e experimento com relação ao processo inflamatório – subgrupos 3 dias (p = 1), 7 dias (p = 0,474) e 14 dias (p = 303). A avaliação dos colágenos tipo I e III no grupo-controle não demonstrou benefícios de cicatrização – 3 dias (p = 0,436), 7 dias (p = 0,853) e 14 dias (p = 0,436); já no grupo experimental, houve aumento dos colágenos tipos I e III nos subgrupos 3 e 14 dias (p = 0,005). A imuno-histoquímica confirmou os resultados encontrados na coloração hematoxilina eosina, na qual a área de miofibroblastos entre os subgrupos, nos grupos experimental (p = 0,4) e controle (p = 0,336), foi indiferente. Conclusão A utilização do subgalato de bismuto em ferida de pele de ratos não evidenciou benefícios na cicatrização, ou seja, não houve diferença na fibroplasia quando comparados os grupos experimental e controle. PMID:29930592
Geochemistry, geochronology and Nd isotopes of the Gogó da Onça Granite: A new Paleoproterozoic A-type granite of Carajás Province, Brazil

NASA Astrophysics Data System (ADS)

Teixeira, Mayara Fraeda Barbosa; Dall'Agnol, Roberto; Santos, João Orestes Schneider; de Sousa, Luan Alexandre Martins; Lafon, Jean-Michel

2017-12-01

The Gogó da Onça Granite (GOG) comprise a stock located in the Carajás Province in the southeastern part of Amazonian Craton near its border with the Araguaia Belt. Three facies were identified in the pluton: biotite-amphibole granodiorite, biotite-amphibole monzogranite and amphibole-biotite syenogranite. The GGO crosscut discordantly the Archean country rocks and are not foliated. All Gogó da Onça Granite varieties are metaluminous, ferroan A2-subtype granites with reduced character. The major and trace element behavior suggests that its different facies are related by fractional crystallization. Zircon and titanite U-Pb SHRIMP ages show that the pluton crystallized at ∼1880-1870 Ma and is related to the remarkable Paleoproterozoic magmatic event identified in the Carajás Province. Whole-rock Nd isotope data (TDM ages 2.78 to 2.81, εNd values of -9.07 to -9.48) indicate that the GOG magmas derived from an Archaean source compatible with that of some other Paleoproterozoic suites from Carajás Province. The GOG show significant contrasts with the Jamon and Velho Guilherme Paleoproterozoic suites from Carajás Province and the inclusion of the Gogó da Onça granite in any of these suites is not justified. The GOG is more akin to the Serra dos Carajás Suite and to the Seringa and São João granites of Carajás and to the Mesoproterozoic Sherman granite of USA and the Paleoproterozoic Suomenniemi Batholith of Finland. This study puts in evidence the relevance of precise geochronological data and estimation of magma oxidation state in the characterization and correlation of A-type granites.

Um estudo espectrofotométrico da variável cataclísmica V3885 Sgr

NASA Astrophysics Data System (ADS)

Ribeiro, F. M. A.; Diaz, M. P.

2003-08-01

Variáveis Cataclísmicas são sistemas binários cerrados compostos de uma anã vermelha que transfere matéria para uma anã branca, em sistemas não magnéticos ocorre a formação de um disco de acresção em torno da anã branca. V3885 Sgr é uma variável cataclísmica classificada como sendo do tipo nova-like. É apresentado um estudo espectrofotométrico de V3885 Sgr de alta resolução temporal feito na região do visível. A região observada é centrada em Ha e abrange também a linha de HeI 6678. O primeiro resultado obtido neste estudo é a determinação do período orbital a partir de medidas da velocidade radial da linha de Ha como sendo 0,20716071(22) dias, resolvendo inconsistências quanto a esse valor na literatura e definindo uma efeméride a longo prazo para o sistema. Com este período e as medidas de velocidade radial do perfil de linha de Ha foi construído um diagrama de massas, através do qual restringimos as massas das componentes estelares do sistema e limitamos a inclinação orbital do sistema. Foram construídos diagramas de Greenstein para as linhas de Ha e HeI, onde os espectros médios em cada intervalo de fase são representados lado a lado em escala de cinza, indicando a existência de uma emissão intensa proveniente da parte posterior do disco. A partir da tomografia Doppler obtivemos perfis de emissividade radial para o disco tanto para a linha de Ha como para HeI. Os resultados obtidos são comparados com os de outros sistemas estudados com a mesma técnica. Serão apresentados também resultados da tomografia de flickering para o sistema.
An ALS-Associated Mutant SOD1 Rapidly Suppresses KCNT1 (Slack) Na+-Activated K+ Channels in Aplysia Neurons.

PubMed

Zhang, Yalan; Ni, Weiming; Horwich, Arthur L; Kaczmarek, Leonard K

2017-02-22

Mutations that alter levels of Slack (KCNT1) Na + -activated K + current produce devastating effects on neuronal development and neuronal function. We now find that Slack currents are rapidly suppressed by oligomers of mutant human Cu/Zn superoxide dismutase 1 (SOD1), which are associated with motor neuron toxicity in an inherited form of amyotrophic lateral sclerosis (ALS). We recorded from bag cell neurons of Aplysia californica , a model system to study neuronal excitability. We found that injection of fluorescent wild-type SOD1 (wt SOD1YFP) or monomeric mutant G85R SOD1YFP had no effect on net ionic currents measured under voltage clamp. In contrast, outward potassium currents were significantly reduced by microinjection of mutant G85R SOD1YFP that had been preincubated at 37°C or of cross-linked dimers of G85R SOD1YFP. Reduction of potassium current was also seen with multimeric G85R SOD1YFP of ∼300 kDa or >300 kDa that had been cross-linked. In current clamp recordings, microinjection of cross-linked 300 kDa increased excitability by depolarizing the resting membrane potential, and decreasing the latency of action potentials triggered by depolarization. The effect of cross-linked 300 kDa on potassium current was reduced by removing Na + from the bath solution, or by knocking down levels of Slack using siRNA. It was also prevented by pharmacological inhibition of ASK1 (apoptosis signal-regulating kinase 1) or of c-Jun N-terminal kinase, but not by an inhibitor of p38 mitogen-activated protein kinase. These results suggest that soluble mutant SOD1 oligomers rapidly trigger a kinase pathway that regulates the activity of Na + -activated K + channels in neurons. SIGNIFICANCE STATEMENT Slack Na + -activated K + channels (KCNT1, K Na 1.1) regulate neuronal excitability but are also linked to cytoplasmic signaling pathways that control neuronal protein translation. Mutations that alter the amplitude of these currents have devastating effects on neuronal
Holocene history of a lake filling and vegetation dynamics of the Serra Sul dos Carajás, southeast Amazonia.

PubMed

Guimarães, José T F; Sahoo, Prafulla K; Souza-Filho, Pedro W M; Figueiredo, Mariana M J Costa DE; Reis, Luiza S; Silva, Marcio S DA; Rodrigues, Tarcísio M

2017-07-24

Down-core changes in sedimentary facies, elemental geochemistry, pollen, spore, δ13C, δ15N and radiocarbon records from a filled lake, named R4, of the Serra Sul dos Carajás were used to study the relationship between the paleomorphological and paleoecological processes and their significance for Holocene paleoclimatology of the southeast Amazonia. The sediment deposition of the R4 lake started around 9500 cal yr BP. Increase of detrital components from 9500 to 7000 cal yr BP suggests high weathering of surrounding catchment rocks and soils, and deposition into the lake basin under mudflows. At that time, montane savanna and forest formation were already established suggesting predominance of wet climate. However, from 7000 to 3000 cal yr BP, a decline of detrital input occurred. Also, forest formation and pteridophytes were declined, while palms and macrophytes were remained relatively stable, indicating that water levels of the lake is likely dropped allowing the development of plants adapted to subaerial condition under drier climate conditions. After 3000 cal yr BP, eutrophication and low accommodation space lead to high lake productivity and the final stage of the lake filling respectively, and forest formation may has acquired its current structure, which suggests return of wetter climate conditions.
Comparison of the social systems of primates and feral horses: data from a newly established horse research site on Serra D'Arga, northern Portugal.

PubMed

Ringhofer, Monamie; Inoue, Sota; Mendonça, Renata S; Pereira, Carlos; Matsuzawa, Tetsuro; Hirata, Satoshi; Yamamoto, Shinya

2017-10-01

Horses are phylogenetically distant from primates, but considerable behavioral links exist between the two. The sociality of horses, characterized by group stability, is similar to that of primates, but different from that of many other ungulates. Although horses and primates are good models for exploring the evolution of societies in human and non-human animals, fewer studies have been conducted on the social system of horses than primates. Here, we investigated the social system of feral horses, particularly the determinant factors of single-male/multi-male group dichotomy, in light of hypotheses derived from studies of primate societies. Socioecological data from 26 groups comprising 208 feral horses on Serra D'Arga, northern Portugal suggest that these primate-based hypotheses cannot adequately explain the social system of horses. In view of the sympatric existence of multi- and single-male groups, and the frequent intergroup transfers and promiscuous mating of females with males of different groups, male-female relationships of horses appear to differ from those of polygynous primates.
Mercury fluxes in a natural forested Amazonian catchment (Serra do Navio, Amapá State, Brazil).

PubMed

Fostier, A H; Forti, M C; Guimarães, J R; Melfi, A J; Boulet, R; Espirito Santo, C M; Krug, F J

2000-10-09

Mercury (Hg total) fluxes were calculated for rainwater, throughfall and stream water in a small catchment located in the northeastern region of the Brazilian Amazon (Serra do Navio, Amapá State), whose upper part is covered by a natural rainforest and lower part was altered due to deforestation and activities related to manganese mining. The catchment area is 200 km from the nearest gold mining (garimpo). Minimum and maximum Hg concentrations were measured monthly from October 1996 to September 1997 and were 3.5-23.4 ng l(-1) for rainwater, 16.5-82.7 ng l(-1) for throughfall (March-August 1997) and 1.2-6.1 and 4.2-18.8 ng l(-1) for stream water, in natural and disturbed areas, respectively. In the natural area, the inputs were 18.2 microg m 2 year(-1) in rainwater and 72 microg m(-2) year(-1) in throughfall. This enrichment was attributed to dry deposition. The stream output of 2.9 microg m(-2) year(-1) indicates that Hg is being recycled within the forest as other chemical species or is being retained by the soil system, as confirmed by the cumulative Hg burden in the 0-10 cm surface layer, which was 36480 microg m(-2). When the disturbed area of the catchment was included, the stream output was 9.3 microg m(-2), clearly indicating the impact of the deforestation of the lower part of the basin on the release of mercury. The Hg burden in the disturbed area was 7560 microg m(-2) for the 0-10 cm surface layer.
Mouse Na+/K+-ATPase β1-subunit has a K+-dependent cell adhesion activity for β-GlcNAc-terminating glycans

PubMed Central

Kitamura, Noriaki; Ikekita, Masahiko; Sato, Takeshi; Akimoto, Yoshihiro; Hatanaka, Yasumaru; Kawakami, Hayato; Inomata, Mitsushi; Furukawa, Kiyoshi

2005-01-01

A 48-kDa β-N-acetylglucosamine (GlcNAc)-binding protein was isolated from mouse brain by GlcNAc-agarose column chromatography. The N-terminal amino acid residues showed the protein to be a mouse Na+/K+-ATPase β1-subunit. When the recombinant FLAG-β1-subunit expressed in Sf-9 cells was applied to a GlcNAc-agarose column, only the glycosylated 38- and 40-kDa proteins bound to the column. In the absence of KCl, little of the proteins bound to a GlcNAc-agarose column, but the 38- and 40-kDa proteins bound in the presence of KCl at concentrations above 1 mM. Immunohistochemical study showed that the β1-subunit and GlcNAc-terminating oligosaccharides are at the cell contact sites. Inclusion of anti-β1-subunit antibody or chitobiose in cell aggregation assays using mouse neural cells resulted in inhibition of cell aggregation. These results indicate that the Na+/K+-ATPase β1-subunit is a potassium-dependent lectin that binds to GlcNAc-terminating oligosaccharides: it may be involved in neural cell interactions. PMID:15705719
A distribuição de velocidades na linha de visada em galáxias barradas vistas de face

NASA Astrophysics Data System (ADS)

Gadotti, D. A.; de Souza, R. E.

2003-08-01

Com o objetivo de realizar um estudo cinemático da componente vertical de barras em galáxias, obtivemos espectros de fenda longa de alta razão S/N ao longo dos eixos maior e menor de 14 galáxias barradas vistas de face, nos telescópios de 1.52m do ESO em La Silla, Chile, e de 2.3m do Steward Observatory em Kitt Peak, Arizona. Estes dados nos permitiram determinar a distribuição de velocidades das estrelas ao longo do eixo vertical das barras e discos destes sistemas, tanto no centro como em pontos que distam cerca de 5 e 20 segundos de arco do núcleo, correspondendo a distâncias de cerca de 0.7 e 2.8 kpc, respectivamente. Desta forma, a variação radial da distribuição de velocidades também pôde ser avaliada. Este tipo de análise tem raros exemplos na literatura por ser caro em termos de tempo de telescópio. Entretanto, é de fácil justificativa, considerando que traz novas informações que podem ser utilizadas para aperfeiçoar modelos teóricos acerca da formação e evolução de galáxias. Um algoritmo por nós desenvolvido foi utilizado para obter as distribuições de velocidades como Gaussianas generalizadas (polinômios de Gauss-Hermite), o que traz um ingrediente a mais neste tipo de estudo que, tradicionalmente, se utiliza de Gaussianas puras, uma hipótese nem sempre razoável. Apresentaremos os resultados deste trabalho, que incluem um diagnóstico para a identificação de barras recém formadas, e testes para o modelo isotérmico de discos. Mostraremos que: (i) a escolha das estrelas padrão em velocidade, e dos parâmetros da Gaussiana, deve ser muito bem justificada já que tem influência significativa nos resultados; (ii) muitas galáxias apresentam uma depressão na dispersão de velocidades na região central, que pode estar associada a um disco interno; e (iii) a dispersão de velocidades é constante ao longo da barra, nos eixos maior e menor, mas cai substancialmente quando se passa da barra para o disco.
A structural analysis of the Minas da Panasqueira vein network and related fracture generations

NASA Astrophysics Data System (ADS)

Jacques, Dominique; Vieira, Romeu; Muchez, Philippe; Sintubin, Manuel

2014-05-01

and tip lines, we try to sort out if a dominant σ2 propagation direction, typical for hydrofractures, exists within the vein network. By doing so, we can evaluate whether the subhorizontal vein network formed under a compressive stress regime, or was mainly dictated by the strength anisotropy of the rocks under near-isotropic stress conditions of σhmax ≡ σhmin. The regional dominance of subhorizontal aplites, pegmatites and hydrothermal veins, exploiting subhorizontal fracture networks, occurs over a wide area of more than 100 km2 along the Serra de Estrela granitic massif (Derré et al., 1986). This orientation contrasts with the more common vertical attitude of granite-related hydrothermal veins, observed throughout the Iberian massif. A detailed orientation analysis of the fracture sets should allow to explore the possible causes of this particular late orogenic, flat-lying fracture network related to the granitic intrusion. References Derré, C., Lecolle, M., Roger, G., Tavares de Freitas Carvalho, J., 1986. Tectonics, magmatism, hydrothermalism and sets of flat joints locally filled by Sn-W, aplite-pegmatite and quartz veins, southeastern border of the Serra de Estrela granitic massif (Beira Baixa, Portugal). Ore Geology Reviews 1, 43-56. Foxford, K. A., Nicholson, R., Polya, D. A., and Hebblethwaite, R. P. B., 2000. Extensional failure and hydraulic valving at Minas da Panasqueira, Portugal; evidence from vein spatial distributions, displacements and geometries. Journal of Structural Geology 22, 1065-1086.
Genotoxic potential generated by biomass burning in the Brazilian Legal Amazon by Tradescantia micronucleus bioassay: a toxicity assessment study

PubMed Central

2011-01-01

Background The Brazilian Amazon has suffered impacts from non-sustainable economic development, especially owing to the expansion of agricultural commodities into forest areas. The Tangará da Serra region, located in the southern of the Legal Amazon, is characterized by non-mechanized sugar cane production. In addition, it lies on the dispersion path of the pollution plume generated by biomass burning. The aim of this study was to assess the genotoxic potential of the atmosphere in the Tangará da Serra region, using Tradescantia pallida as in situ bioindicator. Methods The study was conducted during the dry and rainy seasons, where the plants were exposed to two types of exposure, active and passive. Results The results showed that in all the sampling seasons, irrespective of exposure type, there was an increase in micronucleus frequency, compared to control and that it was statistically significant in the dry season. A strong and significant relationship was also observed between the increase in micronucleus incidence and the rise in fine particulate matter, and hospital morbidity from respiratory diseases in children. Conclusions Based on the results, we demonstrated that pollutants generated by biomass burning in the Brazilian Amazon can induce genetic damage in test plants that was more prominent during dry season, and correlated with the level of particulates and elevated respiratory morbidity. PMID:21575274
Contagem de fontes de radio na direção de aglomerados ricos de galaxias

NASA Astrophysics Data System (ADS)

Andreazza, C. M.; Andernach, H.

A contagem de fontes de rádio, na direção de aglomerados ricos de galáxias, deve fornecer uma distribuçãto acima da média do campo devido aos efeitos do meio. No entanto, a distribução de radiofontes de alguns aglomerados, investigada por vários autores no passado, mostrou, em alguns casos, uma deficência de fontes fracas. Neste trabalho, analisamos os levantamentos em 2.7 GHz (Reuter e Andernach 1990, 1990A&AS...82..279R; Loiseau et al. 1988, 1988A&AS...75...67L) e o catálogo 6CII em 151 MHz (Hales et al. 1988, 1988MNRAS.234..919H). Nosso estudio da distribução de radiofontes, na direção de aglomerados ricos de galáxias, nestas duas frequências, mostra um excesso de fontes fortes somente nas regiões centrais dos aglomerados. Este resultado pode ser explicado devido à evidência de confinamento das radiofontes pelo gás, do meio intra-aglomerado, e devido aos processos de colisão, coalescência e canibalismo de galáxias.
Questões mais freqüentes na área de astronomia

NASA Astrophysics Data System (ADS)

Segundo, H. A. S.; Garcia, G. C.; Caretta, C. A.; Lima, F. P.

2003-08-01

É amplamente reconhecido que as pessoas em geral têm grande fascínio e interesse pela Astronomia. Por outro lado, o conteúdo dessa área incluído no ensino formal está longe de ser abrangente e suficiente para suprir a demanda. Esse interesse permite otimizar a divulgação e o ensino não formal de Astronomia aliando a adequação do conteúdo à expectativa das pessoas. Nesse intuito, nosso trabalho busca mapear que assuntos da Astronomia despertam mais a atenção e o interesse das pessoas e o quanto disso é estimulado pela mídia, que freqüentemente aproveita-se desse interesse de forma sensacionalista, trazendo contribuições positivas e negativas. Para esta avaliação, utilizamos as pesquisas específicas e de caracterização do público que freqüentou o MAst nos anos de 2001 a 2003, pesquisa das matérias de Astronomia veiculadas na mídia escrita da cidade do Rio de Janeiro no mesmo período, além da base de dados do programa Pergunte a um astrônomo, realizado no Observatório Nacional nos anos de 1997 a 1999. Para a análise dos dados, dividimos as perguntas em dez categorias, cada uma com suas subcategorias, tomando como referência as divisões, comissões e grupos de trabalho da IAU. Apresentamos neste trabalho os resultados dessa pesquisa, que incluem, entre outros, a predominância de questões nas categorias Observação do Céu e Sistemas Planetários enquanto nos jornais dominam as notícias de Sistemas Planetários e Espaço & Astronáutica. Outro resultado interessante indicou que as dúvidas de crianças do ensino fundamental se concentram em algumas categorias enquanto as questões de adultos são mais distribuídas por todas as categorias. Os resultados dessa pesquisa serão aplicados diretamente no aperfeiçoamento das atividades do Programa de Observação de Céu, bem como na elaboração de novos projetos e eventos realizados no MAst.
Inhibition of epithelial Na sup + transport by atriopeptin, protein kinase c, and pertussis toxin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohrmann, M.; Cantiello, H.F.; Ausiello, D.A.

1987-08-01

The authors have recently shown the selective inhibition of an amiloride-sensitive, conductive pathway for Na{sup +} by atrial natriuretic peptide and 8-bromoguanosine 3{prime},5{prime}-cyclic monophosphate (8-BrcGMP) in the renal epithelial cell line, LLC-PK{sub i}. Using {sup 22}Na{sup +} fluxes, they further investigated the modulation of Na{sup +} transport by atrial natriuretic peptide and by agents that increase cGMP production, activate protein kinase c, or modulate guanine nucleotide regulatory protein function. Sodium nitroprusside increases intracellular cGMP concentrations without affecting cAMP concentrations and completely inhibits amiloride-sensitive Na{sup +} uptake in a time- and concentration-dependent manner. Oleoyl 2-acetylglycerol and phorbol 12-myristate 13-acetate, activators ofmore » protein kinase c, inhibit Na{sup +} uptake by 93 {plus minus} 13 and 51 {plus minus} 10%, respectively. Prolonged incubation with phorbol ester results in the downregulation of protein kinase c activity and reduces the inhibitory effect of atrial natriuretic peptide, suggesting that the action of this peptide involves stimulation of protein kinase c. Pertussis toxin, which induces the ADP-ribosylation of a 41-kDa guanine nucleotide regulatory protein in LLC-PK{sub i} cells, inhibits {sup 22}Na{sup +} influx to the same extent as amiloride. Thus, increasing cGMP, activating protein kinase c, and ADP-ribosylating a guanine nucleotide regulatory protein all inhibit Na{sup +} uptake. These events may be sequentially involved in the action of atrial natriuretic peptide.« less
ANÁLISE DA INSERÇÃO DOS TEMAS DE HUMANIDADES E ÉTICA, COM METODOLOGIA DE APRENDIZAGEM BASEADA EM PROBLEMAS, EM CURRICULO MÉDICO INTEGRADO EM ESCOLA PÚBLICA NO DISTRITO FEDERAL, BRASIL

PubMed Central

Novaes, Maria Rita Carvalho Garbi; Novaes, Luiz Carlos Garcez; Guilhem, Dirce; Lolas, Fernando; Silveira, Carla; Guiotti, Murilo

2009-01-01

Objetivo Realizar uma análise da inserção da ética e humanidades no currículo do Curso de Medicina da Escola Superior em Ciências da Saúde - ESCS, escola pública do Distrito Federal, Brasil, de forma a contribuir com o processo de gestão curricular. Metodologia O Estudo é de coorte e documental. Foram pesquisados 37 termos relacionados à ética e 36 referentes à humanização nos objetivos educacionais e conteúdo dos módulos temáticos, habilidades e atitudes e interação ensino-serviço-comunidade, de 1a a 4a série e no programa do internato no currículo (ano 2006) e no projeto pedagógico do Curso de Medicina (2001). Resultados Maior inserção da humanização, ética e bioética na 1a e 2a série, quando comparado à inserção na 3a e 4a série e no internato, (IC95%-α=0,034, pvalue=0,007). Unidade de habilidades e atitudes: freqüência das 3 temáticas no currículo da 1a a 4a séries (IC95%-α=0,026, pvalue=0,013). Quando comparada a inserção entre o internato e as quatro primeiras séries, observa-se que nestas a inserção da temática humanização é superior (IC95%-α=0,042, pvalue=0,029). Conclusão O currículo desenvolvido no ano de 2006 na ESCS apresentou correlação com o projeto pedagógico do curso e contemplou a temática de forma abrangente, em todas as séries e internato. PMID:20396594
Perfil dos Professores de Ciências Naturais do Recôncavo da Bahia - Alunos da Disciplina Terra e Universo no Curso de Ciências Naturais do Parfor

NASA Astrophysics Data System (ADS)

Lima, S. R.; Cerqueira Júnior, W.; Dutra, G.

2011-12-01

Este trabalho foi desenvolvido pelo projeto Astronomia no Recôncavo da Bahia, no Centro de Formação de Professores da Universidade Federal do Recôncavo da Bahia. Traçamos o perfil de um grupo de professores que lecionam conteúdos de Ciências Naturais no recôncavo, alunos do curso de Licenciatura em Ciências Naturais, oferecido dentro do Plano Nacional de Formação de Professores da Educação Básica. Nosso objetivo era avaliar se eles estão preparados para trabalhar conteúdos de Astronomia e identificar suas dificuldades. Os resultados serviram para orientar o professor da disciplina “Terra e Universo”, oferecida no segundo semestre de 2010. Durante a primeira aula da disciplina Terra e Universo, os alunos responderam a um questionário contendo questões abertas e fechadas, divididas em duas partes. A primeira procurando caracterizar profissionalmente os alunos enquanto professores da rede pública da região do Recôncavo Sul da Bahia e uma segunda parte procurando identificar conhecimentos básicos em Astronomia. Os resultados indicam uma predominância de professores do sexo feminino, com idade superior aos 40 anos, pardos e sem formação específica para o ensino de ciências. A maioria leciona há mais de 15 anos para turmas do 1º ao 5º ano, alguns lecionam para turmas de 6º ao 9º ano. Quase todos nunca participaram de um curso de formação continuada em Astronomia. Além disso, não estão habituados a ler revistas especializadas e nem livros com esta temática. Os que procuram ensinar temas voltados para a Astronomia têm, no livro didático, a maior fonte de informação sobre o assunto. As respostas também indicam uma deficiência em conteúdos básicos como a compreensão da esfericidade da Terra, noções de verticalidade e gravidade, incapacidade de identificar a Terra como um planeta, no Sistema Solar, em uma galáxia, no Universo. Estes resultados ressaltam a importância de disciplinas de Astronomia básica na formação dos
Discussions about the Nature of Science in a Course on the History of Astronomy. (Spanish Title: Discusiones sobre la Naturaleza de la Ciencia en un Curso sobre Historia de la Astronomía.) Discussões sobre a Natureza da Ciência em um Curso sobre a História da Astronomia

NASA Astrophysics Data System (ADS)

Pires de Andrade, Victória Flório; L'Astorina, Bruno

2010-07-01

There are an increasing number of researches in science education that affirm the importance of discussions on the "nature of science" in basic education level as well as in teacher training. The history of science applied to education is a way to contextualize epistemological discussions, allowing both the understanding of scientific content and learning about science concepts. We present some reasonably consensual definitions on the nature of science that have been widely discussed by the academic community. We show also some episodes in the history of astronomy which can lead to discussions involving some aspects of the nature of science, and how they can do it. Hay un número creciente de investigaciones en la enseñanza de las ciencias que afirman la importancia de debates sobre la "naturaleza de la ciencia" en la educación básica y formación del profesorado. La historia de la ciencia aplicada a la educación es una manera de contextualizar los debates de la epistemología, lo que permite tanto la comprensión de los contenidos científicos como el aprendizaje de conceptos científicos. En esto trabajo, presentamos algunas definiciones bastante consensuales sobre la naturaleza de la ciencia que han sido ampliamente discutidas por la comunidad académica y mostramos cómo algunos episodios en la historia de la astronomía pueden llevar a discusiones sobre algunos aspectos de la naturaleza de la ciencia. Há um número crescente de pesquisas na área de ensino de ciências que afirmam a importância de discussões sobre a "natureza da ciência" na educação básica e na formação de professores. A história da ciência aplicada ao ensino é uma maneira de contextualizar discussões epistemológicas, permitindo tanto a compreensão de conteúdos científicos quanto o aprendizado de noções sobre as ciências. Neste trabalho apresentamos algumas definições razoavelmente consensuais sobre a natureza da ciência que foram amplamente discutidas pela
A estabilidade dos PAHS em função da energia da radiação interestelar nas faixas UV e raios-X

NASA Astrophysics Data System (ADS)

Pinotti, R.; Costa, R. K.; Boechat-Roberty, H. M.; Lago, A.; Souza, G. B.

2003-08-01

A nebulosa CRL 618, uma proto-nebulosa planetária cuja nuvem molecular espessa envolve uma estrela B0, contém uma grande quantidade de C2H2 e CH4. Estas moléculas são consideradas os tijolos da criação de grandes moléculas carbonadas como os Hidrocarbonetos Policíclicos Aromáticos (PAHs). Esta nebulosa, por estar exposta a intensos campos de UV e Raios-X, é uma região de fotodissociação molecular que propicia a formação de novas moléculas, confirmada pela presença de C4H2 e C6H6 (Benzeno), que é a unidade básica dos PAHs. Atribui-se a esta família de moléculas orgânicas duas propriedades fundamentais, a resistência para sobreviver ao campo de radiação UV interestelar e a geração das bandas de emissão não identificadas (UIR) observadas no infravermelho. No entanto, alguns autores questionam a resistência dos PAHs ao campo de radiação UV interestelar. Empregando a técnica de Espectrometria de Massas por Tempo de Vôo, no modo de coincidência fotoelétron-fotoíon, estudamos a ionização e fragmentação das seguintes moléculas: Benzeno, Benzeno deuterado, Naftaleno, Antraceno e Fenantreno. Utilizamos uma fonte de Hélio monocromática em 21,21 eV (584,5 Å) e a radiação Síncroton do Laboratório Nacional de Luz Síncroton (LNLS) em diferentes energias nas proximidades da borda do C 1s ( 290 eV). Comprovamos a estabilidade dos PAHs sob ação de UV (21,21 eV), onde eles apresentam um baixo nível de fotodissociação, produzindo fragmentos ionizados com rendimento total na ordem de 5 por cento em relação ao íon molecular pai. Entretanto, em altas energias, na faixa de Raios-X, a quebra destas moléculas torna-se mais intensa, com a produção de muitos fragmentos. Como uma das rotas de fragmentação do Naftaleno é [(C10H8) = > (C6H6+) + (C4H2) + (e-)], e como temos as evidências observacionais da existência do C4H2 e C6H6 na nebulosa CRL 618, sugerimos que este ambiente também possui o Naftaleno.
Projeto educação em ciências com observatórios virtuais: a participação da Escola Moppe no período 2000-2003

NASA Astrophysics Data System (ADS)

Wuensche, C. A.; Gavioli, E.; Oliveira, A. L. P. R. S.; da Silva, C.; Cardoso, H. P.; Estácio, S.

2003-08-01

O projeto Educação em Ciências com Observatórios Virtuais foi concebido pelo Instituto Astronômico e Geofísico da USP, agregando diversas instituições de ensino e pesquisa no país para desenvolver competências diversas na educação fundamental, média e superior utilizando a astronomia como ferramenta multidisciplinar. Este trabalho descreve a participação da MOPPE, escola-piloto do INPE no projeto, no período de 2000-2003. Serão apresentadas 1) a criação de um clube de ciências (1999 a 2001) cujo tema foi a colonização de Marte e 2) a ementa de astronomia trabalhada com as 7a. e 8a. séries do ensino fundamental. A proposta do projeto Colonizando Marte foi estudar diversos aspectos de uma missão interplanetária e construir experiementos que permitissem quantificar esses aspectos. Os resultados obtidos incluiram apresentações nas SBPC Jovem em 2000 e 2001. Discutiremos também as ementas de astronomia trabalhadas desde 2001 e o envolvimento dos alunos com atividades ligadas a astronomia, fora da aula de ciências. A inclusão de astronomia no currículo das últimas séries motivou a participação de mais alunos culminando com a conquista de duas medalhas para alunos da 7a. série na Olimpiada Brasileira de Astronomia em 2002. Houve também um aumento no número de participantes na OBA 2003 e nos projetos de astronomia mais elaborados nas Feira de Ciências de 2001 e 2002. Destacamos em 2003 a inclusão da MOPPE no projeto TIE - Telescopes in Education - da NASA, que utiliza o telescópio do Observatório de Mount Wilson (EUA) para observações remotas em projetos pedagógicos para o ensino de astronomia.
Growth of binary organic NLO crystals: m.NA-p.NA and m.NA-CNA system

NASA Technical Reports Server (NTRS)

Singh, N. B.; Henningsen, T.; Hopkins, R. H.; Mazelsky, R.

1993-01-01

Experiments were carried out to grow 3.Nitroaniline (m.NA) crystals doped with 4.Nitroaniline (p.NA) and 2.chloro 4.Nitroaniline (CNA). The measured undercooling for m.NA, p.NA, and CNA were 0.21 tm K, 0.23 tm K, and 0.35 tm K respectively, where tm represents the melting temperature of the pure component. Because of the crystals' large heat of fusion and large undercooling, it was not possible to grow good quality crystals with low thermal gradients. In the conventional two-zone Bridgman furnace we had to raise the temperature of the hot zone above the decomposition temperature of CNA, p.NA, and m.NA to achieve the desired thermal gradient. To avoid decomposition, we used an unconventional Bridgman furnace. Two immiscible liquids, silicone oil and ethylene glycol, were used to build a special two-zone Bridgman furnace. A temperature gradient of 18 K/cm was achieved without exceeding the decomposition temperature of the crystal. The binary crystals, m.NA-p.NA and m.NA-CNA, were grown in centimeter size in this furnace. X-ray and optical characterization showed good optical quality.
Nitrogen and Phosphorous Flow in Atlantic Forest Covered Watersheds on the Oceanic and Continental Slopes at Serra dos Órgãos mountain, Southeast of Brazil

NASA Astrophysics Data System (ADS)

Vidal, M. M.; De Souza, P.; De Mello, W. Z.; Damaceno, I.; Bourseau, L.; Rodrigues, R. D. A.; Mattos, B. B.

2017-12-01

Concentration of nutrients above natural levels are found even at remote or protected environments due to atmospheric transportation from biomass burning emissions, urban and industrial areas. This study evaluate N and P atmospheric deposition at the oceanic and continental slopes of Serra dos Órgãos mountain, which are influenced by the pollutants emission from the Metropolitan Region of Rio de Janeiro. Flux of dissolved forms of N and P were measured in three watersheds in headwaters of Piabanha basin, southeastern Brazil, to understand the dynamics of the biogeochemical processes of these elements, related to anthropic influences of atmospheric inputs and export via stream flow. Samples of bulk precipitation (weekly; n=47) and stream water (monthly; n=13) were collected along one year (Sept 2014 - Sept 2015). During that period the annual rainfall in the oceanic slope (2163 mm) was the double of the continental one. It is important to stress that the rainfall in the oceanic slope was 13 % and 28% in 2014/15, respectively, lower than the long term average. Atmospheric deposition of total dissolved nitrogen (TDN) on the oceanic and continental slopes were, respectively, 15 and 8.6 kg N ha-1 year-1. The TDN outputs by stream water were 5-7 times lower in oceanic slope and 28 times lower on the continental one. The relative contribution of dissolved organic nitrogen (DON; 65%-70%) was higher than the one of dissolved inorganic nitrogen (DIN; 30-35%) to TDN deposition. Atmospheric deposition of total dissolved phosphorus (TDP) in oceanic and continental slopes were 1.4 and 0.95 kg P ha-1 year-1. Dissolved Organic Phosphorus (DOP; 89-96%) was higher than the inorganic one (PO43-; 5-11%). TDP outputs were 2-4 times lower, regarding to atmospheric contribution. The contribution of DOP (73-77 %) was higher than DIP (23-27 %). Results show variations in quantities and forms of N and P species due to natural and anthropogenic processes which contribute to the cycling of
Thermal decomposition of sodium amide, NaNH2, and sodium amide hydroxide composites, NaNH2-NaOH.

PubMed

Jepsen, Lars H; Wang, Peikun; Wu, Guotao; Xiong, Zhitao; Besenbacher, Flemming; Chen, Ping; Jensen, Torben R

2016-09-14

Sodium amide, NaNH 2 , has recently been shown to be a useful catalyst to decompose NH 3 into H 2 and N 2 , however, sodium hydroxide is omnipresent and commercially available NaNH 2 usually contains impurities of NaOH (<2%). The thermal decomposition of NaNH 2 and NaNH 2 -NaOH composites is systematically investigated and discussed. NaNH 2 is partially dissolved in NaOH at T > 100 °C, forming a non-stoichiometric solid solution of Na(OH) 1-x (NH 2 ) x (0 < x < ∼0.30), which crystallizes in an orthorhombic unit cell with the space group P2 1 2 1 2 1 determined by synchrotron powder X-ray diffraction. The composite xNaNH 2 -(1 - x)NaOH (∼0.70 < x < 0.72) shows a lowered melting point, ∼160 °C, compared to 200 and 318 °C for neat NaNH 2 and NaOH, respectively. We report that 0.36 mol of NH 3 per mol of NaNH 2 is released below 400 °C during heating in an argon atmosphere, initiated at its melting point, T = 200 °C, possibly due to the formation of the mixed sodium amide imide solid solution. Furthermore, NaOH reacts with NaNH 2 at elevated temperatures and provides the release of additional NH 3 .

Current distribution of Achatina fulica, in the state of São Paulo including records of Aelurostrongylus abstrusus (Nematoda) larvae infestation.

PubMed

Ohlweiler, Fernanda Pires; Guimarães, Marisa Cristina de Almeida; Takahashi, Fernanda Yoshika; Eduardo, Juliana Manas

2010-01-01

The currently known distribution range of Achatina fulica Bowdich, 1822, in the state of São Paulo, Brazil, is presented. The record of A. fulica naturally infested with Aelurostrongylus abstrusus larvae (Railliet, 1898) (Nematoda: Metastrongylidae) can be found in the city of Guaratinguetá. It was found A. fulica with Metastrongylidae larvae without known medical and veterinary importance in the cities of Carapicuíba, Embu-Guaçu, Itapevi, São Caetano do Sul, São Paulo and Taboão da Serra.
Condition of Si crystal formation by vaporizing Na from NaSi

NASA Astrophysics Data System (ADS)

Morito, Haruhiko; Karahashi, Taiki; Yamane, Hisanori

2012-09-01

NaSi was heated at various Na vapor pressures (pNa 0.1-1.2 atm) and temperatures (973-1173 K) to investigate the condition of Si crystal formation from NaSi by Na evaporation. Silicon single crystals 1-3 mm in diameter were grown by evaporation of Na from Na-Si melt at 1173 K and pNa=0.74 atm.
Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

You, Ya; Yu, Xi -Qian; Yin, Ya -Xia

Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmospheremore » during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g -1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.« less
Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

DOE PAGES

You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; ...

2014-10-27

Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmospheremore » during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g -1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.« less
Compensatory regulation of Na+ absorption by Na+/H+ exchanger and Na+-Cl- cotransporter in zebrafish (Danio rerio)

PubMed Central

2013-01-01

Introduction In mammals, internal Na+ homeostasis is maintained through Na+ reabsorption via a variety of Na+ transport proteins with mutually compensating functions, which are expressed in different segments of the nephrons. In zebrafish, Na+ homeostasis is achieved mainly through the skin/gill ionocytes, namely Na+/H+ exchanger (NHE3b)-expressing H+-ATPase rich (HR) cells and Na+-Cl- cotransporter (NCC)-expressing NCC cells, which are functionally homologous to mammalian proximal and distal convoluted tubular cells, respectively. The present study aimed to investigate whether or not the functions of HR and NCC ionocytes are differentially regulated to compensate for disruptions of internal Na+ homeostasis and if the cell differentiation of the ionocytes is involved in this regulation pathway. Results Translational knockdown of ncc caused an increase in HR cell number and a resulting augmentation of Na+ uptake in zebrafish larvae, while NHE3b loss-of-function caused an increase in NCC cell number with a concomitant recovery of Na+ absorption. Environmental acid stress suppressed nhe3b expression in HR cells and decreased Na+ content, which was followed by up-regulation of NCC cells accompanied by recovery of Na+ content. Moreover, knockdown of ncc resulted in a significant decrease of Na+ content in acid-acclimated zebrafish. Conclusions These results provide evidence that HR and NCC cells exhibit functional redundancy in Na+ absorption, similar to the regulatory mechanisms in mammalian kidney, and suggest this functional redundancy is a critical strategy used by zebrafish to survive in a harsh environment that disturbs body fluid Na+ homeostasis. PMID:23924428
Hydrogen-fluorine exchange in NaBH4-NaBF4.

PubMed

Rude, L H; Filsø, U; D'Anna, V; Spyratou, A; Richter, B; Hino, S; Zavorotynska, O; Baricco, M; Sørby, M H; Hauback, B C; Hagemann, H; Besenbacher, F; Skibsted, J; Jensen, T R

2013-11-07

Hydrogen-fluorine exchange in the NaBH4-NaBF4 system is investigated using a range of experimental methods combined with DFT calculations and a possible mechanism for the reactions is proposed. Fluorine substitution is observed using in situ synchrotron radiation powder X-ray diffraction (SR-PXD) as a new Rock salt type compound with idealized composition NaBF2H2 in the temperature range T = 200 to 215 °C. Combined use of solid-state (19)F MAS NMR, FT-IR and DFT calculations supports the formation of a BF2H2(-) complex ion, reproducing the observation of a (19)F chemical shift at -144.2 ppm, which is different from that of NaBF4 at -159.2 ppm, along with the new absorption bands observed in the IR spectra. After further heating, the fluorine substituted compound becomes X-ray amorphous and decomposes to NaF at ~310 °C. This work shows that fluorine-substituted borohydrides tend to decompose to more stable compounds, e.g. NaF and BF3 or amorphous products such as closo-boranes, e.g. Na2B12H12. The NaBH4-NaBF4 composite decomposes at lower temperatures (300 °C) compared to NaBH4 (476 °C), as observed by thermogravimetric analysis. NaBH4-NaBF4 (1:0.5) preserves 30% of the hydrogen storage capacity after three hydrogen release and uptake cycles compared to 8% for NaBH4 as measured using Sievert's method under identical conditions, but more than 50% using prolonged hydrogen absorption time. The reversible hydrogen storage capacity tends to decrease possibly due to the formation of NaF and Na2B12H12. On the other hand, the additive sodium fluoride appears to facilitate hydrogen uptake, prevent foaming, phase segregation and loss of material from the sample container for samples of NaBH4-NaF.
Computing gas solubility in reservoir waters for environmental chemistry applications: the role of satellite observations

NASA Astrophysics Data System (ADS)

Rosa, R.; Lima, I.; Ramos, F.; Bambace, L.; Assireu, A.; Stech, J.; Novo, E.; Lorenzeti, L.

Atmospheric greenhouse gases concentration has increased during the past centuries basically due to biogenic and pyrogenic anthopogenic emissions Recent investigations have shown that gas emission methane as an important example from tropical hydroelectric reservoirs may comprise a considerable fraction of the total anthropogenic bulk In order to evaluate the concentration of gases of potential importance in environmental chemistry the solubility of such gases have been collected and converted into a uniform format using the Henry s law which states that the solubility of a gas in a liquid is directly proportional to its partial pressure However the Henry s law can be derived as a function of temperature density molar mixing ratio in the aqueous phase and molar mass of water In this paper we show that due to the complex temperature variation and water composition measured in brazilian tropical reservoirs as Serra da Mesa and Manso expressive secular variation on the traditional solubility constants concentration of a species in the aqueous phase by the partial pressure of that species in the gas phase can change in a rate of approximately 30 in 6 decades This estimation comes from a computational analysis of temperature variation measured during 6 months in Serra da Mesa and Manso reservoirs taking into account a simulated density and molar mass variation of the aqueous composition in these environments As an important global change issue from this preliminary analysis we discuss its role in the current estimations on the concentration emission rates
Na/K pump inactivation, subsarcolemmal Na measurements, and cytoplasmic ion turnover kinetics contradict restricted Na spaces in murine cardiac myocytes

PubMed Central

Lu, Fang-Min

2017-01-01

Decades ago, it was proposed that Na transport in cardiac myocytes is modulated by large changes in cytoplasmic Na concentration within restricted subsarcolemmal spaces. Here, we probe this hypothesis for Na/K pumps by generating constitutive transsarcolemmal Na flux with the Na channel opener veratridine in whole-cell patch-clamp recordings. Using 25 mM Na in the patch pipette, pump currents decay strongly during continuous activation by extracellular K (τ, ∼2 s). In contradiction to depletion hypotheses, the decay becomes stronger when pump currents are decreased by hyperpolarization. Na channel currents are nearly unchanged by pump activity in these conditions, and conversely, continuous Na currents up to 0.5 nA in magnitude have negligible effects on pump currents. These outcomes are even more pronounced using 50 mM Li as a cytoplasmic Na congener. Thus, the Na/K pump current decay reflects mostly an inactivation mechanism that immobilizes Na/K pump charge movements, not cytoplasmic Na depletion. When channel currents are increased beyond 1 nA, models with unrestricted subsarcolemmal diffusion accurately predict current decay (τ ∼15 s) and reversal potential shifts observed for Na, Li, and K currents through Na channels opened by veratridine, as well as for Na, K, Cs, Li, and Cl currents recorded in nystatin-permeabilized myocytes. Ion concentrations in the pipette tip (i.e., access conductance) track without appreciable delay the current changes caused by sarcolemmal ion flux. Importantly, cytoplasmic mixing volumes, calculated from current decay kinetics, increase and decrease as expected with osmolarity changes (τ >30 s). Na/K pump current run-down over 20 min reflects a failure of pumps to recover from inactivation. Simulations reveal that pump inactivation coupled with Na-activated recovery enhances the rapidity and effectivity of Na homeostasis in cardiac myocytes. In conclusion, an autoregulatory mechanism enhances cardiac Na/K pump activity when
76 FR 12627 - Airworthiness Directives; Diamond Aircraft Industries GmbH Models DA 42, DA 42 NG, and DA 42 M-NG...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-08

... Industries GmbH Models DA 42, DA 42 NG, and DA 42 M-NG Airplanes AGENCY: Federal Aviation Administration (FAA... on Diamond aeroplanes, the majority of which were DA 40. In additional, at least 18 doors have been... conditions) while the aeroplane was parked. All DA 40 and DA 42 aeroplanes have a system installed that...
Autocorrelation descriptor improvements for QSAR: 2DA_Sign and 3DA_Sign

NASA Astrophysics Data System (ADS)

Sliwoski, Gregory; Mendenhall, Jeffrey; Meiler, Jens

2016-03-01

Quantitative structure-activity relationship (QSAR) is a branch of computer aided drug discovery that relates chemical structures to biological activity. Two well established and related QSAR descriptors are two- and three-dimensional autocorrelation (2DA and 3DA). These descriptors encode the relative position of atoms or atom properties by calculating the separation between atom pairs in terms of number of bonds (2DA) or Euclidean distance (3DA). The sums of all values computed for a given small molecule are collected in a histogram. Atom properties can be added with a coefficient that is the product of atom properties for each pair. This procedure can lead to information loss when signed atom properties are considered such as partial charge. For example, the product of two positive charges is indistinguishable from the product of two equivalent negative charges. In this paper, we present variations of 2DA and 3DA called 2DA_Sign and 3DA_Sign that avoid information loss by splitting unique sign pairs into individual histograms. We evaluate these variations with models trained on nine datasets spanning a range of drug target classes. Both 2DA_Sign and 3DA_Sign significantly increase model performance across all datasets when compared with traditional 2DA and 3DA. Lastly, we find that limiting 3DA_Sign to maximum atom pair distances of 6 Å instead of 12 Å further increases model performance, suggesting that conformational flexibility may hinder performance with longer 3DA descriptors. Consistent with this finding, limiting the number of bonds in 2DA_Sign from 11 to 5 fails to improve performance.
Effects of acute amphetamine (AMPH) treatment on rat striatal dopamine (DA) receptor activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roseboom, P.H.; Iwaniec, L.M.; Ackerman, J.M.

1986-03-05

Upon administration of AMPH rats display a complex series of dose and time dependent behaviors and changes in dopaminergic activity. They found a decrease in D1 DA receptor-stimulated adenylate cyclase (DA-AC) activity in rat striatal membranes after acute in vivo AMPH at a dose and time of intense stereotyped behavior. The Ka for D1-AC activity increased and the Vmax decreased in striatal membranes from rats given 7.5 mg/kg AMPH i.p. and killed 1 hr later as compared to saline (SAL) controls. They examined whether the decrease of DA-AC was due to a change in receptor number or activation of GTP-bindingmore » protein, Ns. Female Holtzman rats were injected with SAL or 7.5 mg/kg AMPH and killed 1 hr later. A 27,000 x g striatal particulate fraction was prepared for AC assay or (/sup 3/H)DA binding with 10 nM spiroperidol. They found no difference in stimulation of AC by NaF, GTP or GppNHp at any dose tested in membranes from SAL- and AMPH-treated rats. Calmodulin-stimulated AC was also unchanged after AMPH. Specific binding at a saturating concentration of (/sup 3/H)DA was 191 +/- 31 and 117 +/- 14 fmol/mg prot in membranes from SAL- and AMPH-treated rats, respectively. This suggests an alteration is occurring at the level of the D1 receptor rather than at coupling of Ns with the AC catalytic subunit.« less
Na+/Ca2+ exchange and Na+/K+-ATPase in the heart

PubMed Central

Shattock, Michael J; Ottolia, Michela; Bers, Donald M; Blaustein, Mordecai P; Boguslavskyi, Andrii; Bossuyt, Julie; Bridge, John H B; Chen-Izu, Ye; Clancy, Colleen E; Edwards, Andrew; Goldhaber, Joshua; Kaplan, Jack; Lingrel, Jerry B; Pavlovic, Davor; Philipson, Kenneth; Sipido, Karin R; Xie, Zi-Jian

2015-01-01

This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field. PMID:25772291
Chronic treatment of DA-8159, a new phosphodiesterase type V inhibitor, attenuates endothelial dysfunction in stroke-prone spontaneously hypertensive rat.

PubMed

Choi, Seul Min; Kim, Jee Eun; Kang, Kyung Koo

2006-02-09

This study examined the effects of chronic treatment of a new phosphodiesterase type 5 inhibitor, DA-8159, on endothelial dysfunction in stroke-prone spontaneously hypertensive rats (SHR-SP). Six-week-old male SHR-SP were divided into 4 groups; vehicle control, DA-8159 1, 3, and 10 mg/kg/day. During a 32-week experimental period, the animals were administered DA-8159 orally and fed a 4% NaCl-loaded diet. The systolic blood pressure was measured every two weeks throughout the experimental period using the tail-cuff method. At the end of experiments, the vascular function (acetylcholine-induced vasodilation) in the endothelium-intact aortic rings was investigated. In addition, the mortality, the left ventricular hypertrophy index, the plasma parameters and the incidence of a cerebral infarction were assessed. In the DA-8159 treated-rats, the vascular reactivity improved significantly in a dose-dependent manner. Although DA-8159 did not alter the elevation of the systolic blood pressure directly, the 3 and 10 mg/kg/day DA-8159 treatment delayed the early death caused by stroke. DA-8159 significantly reduced the left ventricular heart weight/body weight ratio compared with the vehicle control group. Furthermore, the DA-8159 treatment significantly increased the plasma nitric oxide, cGMP, and the total antioxidative status. The DA-8159 treatment also reduced the occurrence of stroke-associated cerebral damage. These results indicate that DA-8159 can ameliorate an endothelial dysfunction-related vascular injury. Therefore, pharmacological intervention aimed at attenuating an endothelial dysfunction is important and might be useful in both preventing and treating endothelial dysfunction-related complications.
Doença cística da adventícia na veia basílica: relato de caso

PubMed Central

Vasconcelos, Rafael Sampaio; Cherubim, Cesar Augusto; França, Felipe Mavignier Pereira; D'allacqua, Eduardo de Lucca; Dalio, Marcelo Bellini; Joviliano, Edwaldo Edner

2016-01-01

Resumo A doença cística da adventícia é uma entidade rara que acomete principalmente a artéria poplítea. A ocorrência em veias é muito rara, e sua etiologia é desconhecida. Clinicamente, apresenta-se como isquemia, trombose ou dor a depender do território acometido. Apresentamos o caso de um paciente masculino jovem referindo nódulo no braço esquerdo. A angiorressonância magnética do membro mostrou lesão cística em contato com a veia basílica, com conteúdo homogêneo e sem realce pós-contraste. Foi realizada ressecção da lesão em bloco com o segmento venoso envolvido. O estudo anatomopatológico foi sugestivo de cisto de adventícia de veia basílica.
Shared epitopes of glycoprotein A and protein 4.1 defined by antibody NaM10-3C10.

PubMed

Rasamoelisolo, M; Czerwinski, M; Willem, C; Blanchard, D

1998-06-01

We have produced the murine monoclonal antibody (MAb) NaM70-3C10 (IgM) from splenocytes of mice immunized with human red blood cells (RBCs). The MAb agglutinated untreated as well as trypsin, chymotrypsin, neuraminidase, or ficin-treated RBCs from controls. In contrast, control RBCs treated with papaine or bromelaine were not agglutinated. On immunoblots, the MAb bound to glycophorin A (GPA) and to a 80 kDa protein identified as protein 4.1. Analysis by agglutination of variant RBCs carrying hybrid glycophorins made of the N-terminus (amino acids 1-58) of GPA and of the C-terminus (amino acids 27-72) of glycophorin B (GPB) and competition-inhibition test using purified GPA and a synthetic peptide corresponding to the amino acid sequence 48-58 of GPA demonstrated that the epitope is located within residues 48-58 of GPA. Epitope analysis with immobilized peptides showed that the MAb recognizes the sequence 53Pro-Pro-Glu-Glu-GIu58 of GPA. A homologous sequence is also present within amino acids 395 to 405 of protein 4.1. Finally, the MAb bound to 16 kDa chymotryptic peptide of protein 4.1, which carries the above amino acid sequence. In conclusion, it may be assumed that NaM70-3C10 specifically recognizes a common epitope on the extracellular domain of GPA and on the intracellular protein 4.1; this specificity explains the persistence of the 80 kDa band on blots when RBCs are treated with papain.
The Na+-Translocating NADH:Quinone Oxidoreductase Enhances Oxidative Stress in the Cytoplasm of Vibrio cholerae

PubMed Central

Muras, Valentin; Dogaru-Kinn, Paul; Minato, Yusuke; Häse, Claudia C.

2016-01-01

ABSTRACT We searched for a source of reactive oxygen species (ROS) in the cytoplasm of the human pathogen Vibrio cholerae and addressed the mechanism of ROS formation using the dye 2′,7′-dichlorofluorescein diacetate (DCFH-DA) in respiring cells. By comparing V. cholerae strains with or without active Na+-translocating NADH:quinone oxidoreductase (Na+-NQR), this respiratory sodium ion redox pump was identified as a producer of ROS in vivo. The amount of cytoplasmic ROS detected in V. cholerae cells producing variants of Na+-NQR correlated well with rates of superoxide formation by the corresponding membrane fractions. Membranes from wild-type V. cholerae showed increased superoxide production activity (9.8 ± 0.6 μmol superoxide min−1 mg−1 membrane protein) compared to membranes from the mutant lacking Na+-NQR (0.18 ± 0.01 μmol min−1 mg−1). Overexpression of plasmid-encoded Na+-NQR in the nqr deletion strain resulted in a drastic increase in the formation of superoxide (42.6 ± 2.8 μmol min−1 mg−1). By analyzing a variant of Na+-NQR devoid of quinone reduction activity, we identified the reduced flavin adenine dinucleotide (FAD) cofactor of cytoplasmic NqrF subunit as the site for intracellular superoxide formation in V. cholerae. The impact of superoxide formation by the Na+-NQR on the virulence of V. cholerae is discussed. IMPORTANCE In several studies, it was demonstrated that the Na+-NQR in V. cholerae affects virulence in a yet unknown manner. We identified the reduced FAD cofactor in the NADH-oxidizing NqrF subunit of the Na+-NQR as the site of superoxide formation in the cytoplasm of V. cholerae. Our study provides the framework to understand how reactive oxygen species formed during respiration could participate in the regulated expression of virulence factors during the transition from aerobic to microaerophilic (intestinal) habitats. This hypothesis may turn out to be right for many other pathogens which, like V. cholerae, depend on
Análise dos Conceitos Astronômicos Apresentados por Professores de Algumas Escolas Estaduais Brasileiras

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon; Gonzaga, Edson Pereira

2011-12-01

A razão para o desenvolvimento deste trabalho baseia-se no fato de que muitos professores da Educação Básica (EB) não lidam com conceitos relacionados à astronomia, e quando o fazem eles simplesmente seguem livros didáticos que podem conter erros conceituais. Como é de conhecimento geral a astronomia é um dos conteúdos a serem ensinados na EB fazendo parte dos Parâmetros Curriculares Nacionais e das Propostas Curriculares do Estado de São Paulo, mas é um fato, que vários pesquisadores apontam, a existência de muitos problemas no ensino da astronomia. Com o propósito de minimizar algumas dessas deficiências foi realizado um trabalho de pesquisa com a utilização de questionários pré e pós pesquisa, para tanto foi desenvolvido um Curso de Extensão Universitária para professores da Diretoria de Ensino Regional (DE) que abrange Mauá, Ribeirão Pires e Rio Grande da Serra (no Estado de São Paulo) com os seguintes objetivos: levantar concepções alternativas; subsidiar os professores por meio de palestras, debates e workshops, e verificar o sucesso da aprendizagem após o curso, adotando-se como referência, para a análise dos resultados, os dicionários de Língua Portuguesa (FERREIRA, 2004) e Enciclopédico de Astronomia e Astronáutica (MOURĀO, 1995). Portanto, dezesseis questões foram aplicadas antes e após o curso, assim pode-se verificar após a pesquisa que 100,0% dos professores sabiam os nomes das fases da Lua, 97,0% entenderam que o Sistema Solar é composto por oito planetas, 78,1% foram capazes de explicar como ocorre um eclipse lunar, um eclipse solar e um solstício, 72,7% sabiam como explicar a ocorrência das estações do ano; 64,5% explicaram corretamente a ocorrência do equinócio, 89,7% foram capazes de definir adequadamente o termo cometa; 63,6% definiram asteróide, 54,5% meteoro, 58,1% galáxia, e 42,4% planeta. Os resultados obtidos indicam uma aprendizagem significativa por parte dos participantes.
Origin of the DA and non-DA white dwarf stars

NASA Technical Reports Server (NTRS)

Shipman, Harry L.

1989-01-01

Various proposals for the bifurcation of the white dwarf cooling sequence are reviewed. 'Primordial' theories, in which the basic bifurcation of the white dwarf sequence is rooted in events predating the white dwarf stage of stellar evolution, are discussed, along with the competing 'mixing' theories in which processes occurring during the white dwarf stage are responsible for the existence of DA or non-DA stars. A new proposal is suggested, representing a two-channel scenario. In the DA channel, some process reduces the hydrogen layer mass to the value of less than 10 to the -7th. The non-DA channel is similar to that in the primordial scenario. These considerations suggest that some mechanism operates in both channels to reduce the thickness of the outermost layer of the white dwarf. It is also noted that accretion from the interstellar medium has little to do with whether a particular white dwarf becomes a DA or a non-DA star.
The alteration of mRNA expression of SOD and GPX genes, and proteins in tomato (Lycopersicon esculentum Mill) under stress of NaCl and/or ZnO nanoparticles.

PubMed

Alharby, Hesham F; Metwali, Ehab M R; Fuller, Michael P; Aldhebiani, Amal Y

2016-11-01

Five cultivars of tomato having different levels of salt stress tolerance were exposed to different treatments of NaCl (0, 3 and 6 g L -1 ) and ZnO-NPs (0, 15 and 30 mg L -1 ). Treatments with NaCl at both 3 and 6 g L -1 suppressed the mRNA levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) genes in all cultivars while plants treated with ZnO-NPs in the presence of NaCl, showed increments in the mRNA expression levels. This indicated that ZnO-NPs had a positive response on plant metabolism under salt stress. Superior expression levels of mRNA were observed in the salt tolerant cultivars, Sandpoint and Edkawy while the lowest level was detected in the salt sensitive cultivar, Anna Aasa. SDS-PAGE showed clear differences in patterns of protein expression among the cultivars. A negative protein marker for salt sensitivity and ZnO-NPs was detected in cv. Anna Aasa at a molecular weight of 19.162 kDa, while the tolerant cultivar Edkawy had two positive markers at molecular weights of 74.991 and 79.735 kDa.
Low-Altitude Long-Endurance Solar Unmanned Plane for Forest Fire Prevention: Application to the Natural Park of Serra do Xures (spain)

NASA Astrophysics Data System (ADS)

González-Jorge, H.; Bueno, M.; Martínez-Sánchez, J.; Arias, P.

2017-08-01

Unamnned aerial systems (UAS) show great potential in operations related to surveillance. These systems can be successfully applied to the prevention of forest fires, especially those caused by human intervention. The present works focuses on a study of the operational possibilities of the unmanned system "AtlantikSolar" developed by the ETH Zurich for the prevention of forest fires in the Spanish natural park of Serra do Xurés, an area of 20,920 ha with height variations between 300 m and 1,500 m. The operation evaluation of AtlantikSolar is based on the use of Flir Tau 2 LWIR camera as imaging payload which could detect illegal activities in the forest, such as bonfires, uncontrolled burning or pyromaniacs. Flight surveillance is planned for an altitude of 100 m to obey the legal limit of the Spanish UAS regulation. This altitude produces a swath width of 346.4 m and pixel resolution between 1.5 and 1.8 pixels/m. Operation is planned to adapt altitude to the change on the topography and obtain a constant ground resolution. Operational speed is selected to 52 km/h. The UAS trajectory is adapted to the limits of the natural park and the border between Spain and Portugal. Matlab code is developed for mission planning. The complete surveillance of the natural park requires a total time of 15.6 hours for a distance of 811.6 km.

Acidosis Differentially Modulates Inactivation in NaV1.2, NaV1.4, and NaV1.5 Channels

PubMed Central

Vilin, Yury Y.; Peters, Colin H.; Ruben, Peter C.

2012-01-01

NaV channels play a crucial role in neuronal and muscle excitability. Using whole-cell recordings we studied effects of low extracellular pH on the biophysical properties of NaV1.2, NaV1.4, and NaV1.5, expressed in cultured mammalian cells. Low pH produced different effects on different channel subtypes. Whereas NaV1.4 exhibited very low sensitivity to acidosis, primarily limited to partial block of macroscopic currents, the effects of low pH on gating in NaV1.2 and NaV1.5 were profound. In NaV1.2 low pH reduced apparent valence of steady-state fast inactivation, shifted the τ(V) to depolarizing potentials and decreased channels availability during onset to slow and use-dependent inactivation (UDI). In contrast, low pH delayed open-state inactivation in NaV1.5, right-shifted the voltage-dependence of window current, and increased channel availability during onset to slow and UDI. These results suggest that protons affect channel availability in an isoform-specific manner. A computer model incorporating these results demonstrates their effects on membrane excitability. PMID:22701426
Integrative taxonomy methods reveal high mealybug (Hemiptera: Pseudococcidae) diversity in southern Brazilian fruit crops.

PubMed

Pacheco da Silva, Vitor C; Kaydan, Mehmet Bora; Malausa, Thibaut; Germain, Jean-François; Palero, Ferran; Botton, Marcos

2017-11-16

The Serra Gaúcha region is the most important temperate fruit-producing area in southern Brazil. Despite mealybugs (Hemiptera: Pseudococcidae) infesting several host plants in the region, there is a lack of information about the composition of species damaging different crops. A survey of mealybug species associated with commercial fruit crops (apple, persimmon, strawberry and grapes) was performed in Serra Gaúcha between 2013 and 2015, using both morphology and DNA analyses for species identification. The most abundant species were Pseudococcus viburni (Signoret), found on all four host plant species, and Dysmicoccus brevipes (Cockerell), infesting persimmon, vines and weeds. The highest diversity of mealybug species was found on persimmon trees, hosting 20 different taxa, of which Anisococcus granarae Pacheco da Silva & Kaydan, D. brevipes, Pseudococcus sociabilis Hambleton and Ps. viburni were the most abundant. A total of nine species were recorded in vineyards. Planococcus ficus (Signoret) and Pseudococcus longispinus (Targioni Tozzetti) were observed causing damage to grapes for the first time. A single species, Ps. viburni, was found associated with apples, while both Ps. viburni and Ferrisia meridionalis Williams were found on strawberry. Four of the mealybug species found represent new records for Brazil.
Role of Na+ conductance, Na+-H+ exchange, and Na+-K+-2Cl− symport in the regulatory volume increase of rat hepatocytes

PubMed Central

Wehner, Frank; Tinel, Hanna

1998-01-01

In rat hepatocytes under hypertonic stress, the entry of Na+ (which is thereafter exchanged for K+ via Na+-K+-ATPase) plays the key role in regulatory volume increase (RVI).In the present study, the contributions of Na+ conductance, Na+-H+ exchange and Na+-K+-2Cl− symport to this process were quantified in confluent primary cultures by means of intracellular microelectrodes and cable analysis, microfluorometric determinations of cell pH and buffer capacity, and measurements of frusemide (furosemide)/bumetanide-sensitive 86Rb+ uptake, respectively. Osmolarity was increased from 300 to 400 mosmol l−1 by addition of sucrose.The experiments indicate a relative contribution of approximately 4:1:1 to hypertonicity-induced Na+ entry for the above-mentioned transporters and the overall Na+ yield equalled 51 mmol l−1 (10 min)−1.This Na+ gain is in good agreement with the stimulation of Na+ extrusion via Na+-K+-ATPase plus the actual increase in cell Na+, namely 55 mmol l−1 (10 min)−1, as was determined on the basis of ouabain-sensitive 86Rb+ uptake and by means of Na+-sensitive microelectrodes, respectively.The overall increase in Na+ and K+ activity plus the expected concomitant increase in cell Cl− equalled 68 mmol l−1, which fits well with the increase in osmotic activity expected to occur from an initial cell shrinkage to 87.5 % and a RVI to 92.6 % of control, namely 53 mosmol l−1.The prominent role of Na+ conductance in the RVI of rat hepatocytes could be confirmed on the basis of the pharmacological profile of this process, which was characterized by means of confocal laser-scanning microscopy. PMID:9481677
Raízes pós-mitológicas da Astronomia Clássica

NASA Astrophysics Data System (ADS)

di Bartolo, L.; Villas da Rocha, J. F.

2004-02-01

Apresentamos como a invenção de um modelo astronômico e cosmológico fundado em causas naturais foi um processo gestado num ambiente cultural específico, o do advento do pensamento pós-mitológico, que tem como sua raiz mais funda a trajetória particular da Grécia Antiga, com ênfase na resolução de uma grave crise social e a evolução do mundo clássico para o contexto espiritual de um império universal.
The major histocompatibility complex genes impact pain response in DA and DA.1U rats.

PubMed

Guo, Yuan; Yao, Fan-Rong; Cao, Dong-Yuan; Li, Li; Wang, Hui-Sheng; Xie, Wen; Zhao, Yan

2015-08-01

Our recent studies have shown that the difference in basal pain sensitivity to mechanical and thermal stimulation between Dark-Agouti (DA) rats and a novel congenic DA.1U rats is major histocompatibility complex (MHC) genes dependent. In the present study, we further used DA and DA.1U rats to investigate the role of MHC genes in formalin-induced pain model by behavioral, electrophysiological and immunohistochemical methods. Behavioral results showed biphasic nociceptive behaviors increased significantly following the intraplantar injection of formalin in the hindpaw of DA and DA.1U rats. The main nociceptive behaviors were lifting and licking, especially in DA rats (P<0.001 and P<0.01). The composite pain scores (CPS) in DA rats were significantly higher than those in DA.1U rats in both phases of the formalin test (P<0.01). Electrophysiological results also showed the biphasic increase in discharge rates of C and Aδ fibers of L5 dorsal root in the two strains, and the net change of the discharge rate of DA rats was significantly higher than that of DA.1U rats (P<0.05). The mechanical thresholds decreased after formalin injection in both strains (P<0.01), and the net change in the mechanical threshold in DA was greater than that in DA.1U rats (P<0.05). The expression of RT1-B, representation of MHC class II molecule, in laminae I-II of L4/5 spinal cord in DA rats was significantly higher than that in DA.1U rats in the respective experimental group (P<0.05). These results suggested that both DA and DA.1U rats exhibited nociceptive responses in formalin-induced pain model and DA rats were more sensitive to noxious chemical stimulus than DA.1U rats, indicating that MHC genes might contribute to the difference in pain sensitivity. Copyright © 2015 Elsevier Inc. All rights reserved.
Combined activity of post-exercise concentrations of NA and eHsp72 on human neutrophil function: role of cAMP.

PubMed

Giraldo, Esther; Hinchado, María D; Ortega, Eduardo

2013-09-01

Extracellular heat shock proteins of 72 kDa (eHsp72) and noradrenaline (NA) can act as "danger signals" during exercise-induced stress by activating neutrophil function (chemotaxis, phagocytosis, and fungicidal capacity). In addition, post-exercise concentrations of NA increase the expression and release of Hsp72 by human neutrophils, and adrenoreceptors and cAMP are involved in the stimulation of neutrophils by eHsp72. This suggests an interaction between the two molecules in the modulation of neutrophils during exercise-induced stress. Given this context, the aim of the present investigation was to study the combined activity of post-exercise circulating concentrations of NA and eHsp72 on the neutrophil phagocytic process, and to evaluate the role of cAMP as intracellular signal in these effects. Results showed an accumulative stimulation of chemotaxis induced by NA and eHsp72. However, while NA and eHsp72, separately, stimulate the phagocytosis and fungicidal activity of neutrophils, when they act together they do not modify these capacities of neutrophils. Similarly, post-exercise concentrations of NA and eHsp72 separately increased the intracellular level of cAMP, but NA and eHsp72 acting together did not modify the intracellular concentration of cAMP. These results confirm that cAMP can be involved in the autocrine/paracrine physiological regulation of phagocytosis and fungicidal capacity of human neutrophils mediated by NA and eHsp72 in the context of exercise-induced stress. Copyright © 2013 Wiley Periodicals, Inc.
The putative mechanism of Na(+) absorption in euryhaline elasmobranchs exists in the gills of a stenohaline marine elasmobranch, Squalus acanthias.

PubMed

Choe, Keith P; Edwards, Susan L; Claiborne, James B; Evans, David H

2007-02-01

We recently cloned an NHE3 orthologue from the gills of the euryhaline Atlantic stingray (Dasyatis sabina), and generated a stingray NHE3 antibody to unequivocally localize the exchanger to the apical side of epithelial cells that are rich with Na(+)/K(+)-ATPase (A MRC). We also demonstrated an increase in NHE3 expression when stingrays are in fresh water, suggesting that NHE3 is responsible for active Na(+) absorption. However, the vast majority of elasmobranchs are only found in marine environments. In the current study, immunohistochemistry with the stingray NHE3 antibody was used to localize the exchanger in the gills of the stenohaline marine spiny dogfish shark (Squalus acanthias). NHE3 immunoreactivity was confined to the apical side of cells with basolateral Na(+)/K(+)-ATPase and was excluded from cells with high levels of vacuolar H(+)-ATPase. Western blots detected a single protein of 88 kDa in dogfish gills, the same size as NHE3 in stingrays and mammals. These immunological data demonstrate that the putative cell type responsible for active Na(+) absorption in euryhaline elasmobranchs is also present in stenohaline marine elasmobranchs, and suggest that the inability of most elasmobranchs to survive in fresh water is not due to a lack of the gill ion transporters for Na(+) absorption.
Kinetic contribution to extracellular Na+/K+ selectivity in the Na+/K+ pump.

PubMed

Vleeskens, Elizabeth; Clarke, Ronald J

2018-05-01

The sodium potassium pump (Na + ,K + -ATPase) shows a high selectivity for K + over Na + binding from the extracellular medium. To understand the K + selectivity in the presence of a high concentration of competing Na + ions requires consideration of more than just ion binding affinities. Here, equilibrium-based calculations of the extracellular occupation of the Na + ,K + -ATPase transport sites by Na + and K + are compared to fluxes through Na + and K + transport pathways. The results show that, under physiological conditions, there is a 332-fold selectivity for pumping of K + from the extracellular medium into the cytoplasm relative to Na + , whereas equilibrium calculations alone predict only a 7.5-fold selectivity for K + . Thus, kinetic effects make a major contribution to the determination of extracellular K + selectivity.
Combining lead isotopes and cluster analysis to distinguish the Guarani and Serra Geral Aquifer Systems and contaminated waters in a highly industrialized area in Southern Brazil.

PubMed

Kuhn, Isadora Aumond; Roisenberg, Ari

2017-10-01

The Rio dos Sinos Watershed area is located at the Middle-West region of the Rio Grande do Sul State, Southern Brazil, along thirty two municipalities and affecting 1.5 million inhabitants and many important industrial centers. Three main aquifers are recognized in the study area: the unconfined-fractured Serra Geral Aquifer System, the porous Guarani Aquifer System, and the Permian Aquitard. This study aims to understand groundwater, surface water and human activity interactions in the Rio dos Sinos Watershed, evaluating the application of stable lead isotopic ratios analyzed for this propose. Thirty six groundwater samples, 8 surface water samples and 5 liquid effluents of tanneries and landfills samples were measured using a Thermal Ionization Mass Spectrometer Thermo-Finnigan and a Neptune Multi-Collector Inductively Coupled Plasma Mass Spectrometer. Groundwater isotopic ratios have a wider range compared to the surface water, with less radiogenic averages 208 Pb/ 204 Pb = 38.1837 vs 38.4050 (standard deviation = 0.2921 vs 0.1343) and 206 Pb/ 204 Pb = 18.2947 vs 18.4766 (standard deviation = 0.2215 vs 0.1059), respectively. Industrial liquid effluents (tanneries and industrial landfill) have averages 208 Pb/ 204 Pb = 38.1956 and 206 Pb/ 204 Pb = 18.3169, distinct from effluent samples of domestic sanitary landfill (averages 208 Pb/ 204 Pb = 38.2353 and 206 Pb/ 204 Pb = 18.6607). Hierarchical cluster analysis led to distinguish six groups of groundwater, representing the three aquifers that occur in the area, two clusters suggesting groundwater mixtures and one demonstrating a highly contaminated groundwater. By analyzing the cluster results and wells' stratigraphic profiles it was possible to distinguish the different aquifers in the area. The Serra Geral Aquifer System has 206 Pb/ 204 Pb ratios between 18.4718 and 18.7089; 207 Pb/ 204 Pb between 15.6692 and 15.6777; 208 Pb/ 204 Pb between 38.6826 and 38.7616; 207 Pb/ 206 Pb between 0.8372 and 0
Conhecimento Científico e Cotidiano em Astronomia: Uma Investigação com Alunos da Educação Básica

NASA Astrophysics Data System (ADS)

Vieira, J. B.; Longhini, M. D.

2011-12-01

Este texto apresenta resultados de uma investigação que teve como objetivo, investigar como os conhecimentos científicos e do cotidiano relacionados a essa área de conhecimento apresentam na escola de Educação Básica, especialmente, em alunos do Ensino Médio prestes a deixar Educação Básica. Para realização da pesquisa, utilizamos como recurso metodológico a aplicação de um questionário estruturado contendo 47 questões, organizadas em duas categorias: Conhecimento Cotidiano e Conhecimento Científico. As questões da categoria “Conhecimento Cotidiano” possuíam afirmações relacionadas a crendices, contos populares, especulações e temáticas do gênero, as quais, geralmente, estão fora do círculo de discussão da comunidade científica, talvez por não serem consideradas como objeto de estudo da ciência. As questões da categoria “Conhecimento Científico” são relacionadas a conteúdos específicos de Astronomia, as quais são compartilhadas pela comunidade científica e aceitas, pelo menos provisoriamente, como possuindo fundamentação científica. Concluímos que, possuem ainda concepções de temas Astronômicos persistentes à mudança, por exemplo, fases da Lua relacionadas à melhor período para corte de cabelo e também para plantio; estrela cadente e ocasião perfeita para se fazer um pedido. Entretanto, podemos observar no que diz respeito a mitos e superstições, que quase não existe influência destes entre os alunos. Portanto, ao trabalharmos com os alunos determinados conceitos científicos, é importante lembrarmos que o professor não opera no vazio; os alunos são sujeitos de saberes, práticas e, dessa forma constroem e reconstroem saberes. Cabe ao professor ouvir os estudantes reconstruindo junto deles conceitos científicos. Acreditamos que o ensino de Ciências na Educação Básica deve lidar criticamente com o conhecimento cotidiano e científico e, assim, efetivar a Ciência como disciplina educativa
Identificação de radiofontes puntiformes presentes na região observada pelo telescópio BEAST

NASA Astrophysics Data System (ADS)

Oliveira, M. S.; Wuensche, C. A.; Leonardi, R.; Tello, C.

2003-08-01

Radiofontes extragalácticas são um dos principais contaminantes nas medidas da Radiação Cósmica de Fundo (RCF) em freqüências abaixo de 200 GHz. O estudo de seu comportamento espectral permite determinar a contribuição destas fontes às anisotropias intrísincas da RCF. Um dos experimentos recentes concebidos para estudar a RCF é o BEAST (Background Emission Anisotropy Scanning Telescope), cujos primeiros resultados foram publicados em fevereiro de 2003. Nos últimos meses, geramos mapas do céu nas freqüências de 30 GHz e 41 GHz, para um total de 648 horas de observação entre julho e outubro de 2002. Identificamos 4 fontes puntiformes extragalácticas na região do céu situada entre 0h < RA < 24 h e +32° < DEC < +42°, com relação S/R > 4,3 e situadas a pelo menos 25° acima do Plano Galáctico. Suas contrapartidas em 5 GHz, segundo o catálogo GB6, são: J1613+3412, J1635+3808, J0927+3902 e J1642+3948. Estas fontes também foram identificadas pelo satélite WMAP sendo que três coincidem com as observadas pelo BEAST dentro da incerteza do feixe do telescópio e a quarta encontra-se bastante próxima (J1613+3412), embora não seja coincidente. As estimativas preliminares de fluxos obtidas para esses objetos são, respectivamente, 0,51; 0,97; 1,08 e 1,6 Jy em 41 GHz. Usando estes resultados e medidas de fluxos em outras frequências existentes na literatura, apresentamos uma estimativa dos índices espectrais destes objetos no intervalo de frequências entre 4,85 GHz e 41 GHz.
Na and K Dependence of the Na/K Pump in Cystic Fibrosis Fibroblasts

NASA Astrophysics Data System (ADS)

Reznik, Vivian M.; Schneider, Jerry A.; Mendoza, Stanley A.

1981-11-01

The Na and K dependence of the Na/K pump was measured in skin fibroblasts from patients with cystic fibrosis and age/sex-matched controls. Under basal conditions, there was no difference between control and cystic fibrosis cells in protein per cell, intracellular Na and K content, or Na/K pump activity (measured as ouabain-sensitive 86Rb uptake). There was no difference in the Na dependence of the Na/K pump between cystic fibrosis cells and control cells. In cells from patients with cystic fibrosis, the Na/K pump had a significantly lower affinity for K (Km = 1.6 mM) when compared to normals (Km = 0.9 mM). This difference was demonstrated by using two independent experimental designs.
Overexpression of a novel soybean gene modulating Na+ and K+ transport enhances salt tolerance in transgenic tobacco plants.

PubMed

Chen, Huatao; He, Hui; Yu, Deyue

2011-01-01

Salt is an important factor affecting the growth and development of soybean in saline soil. In this study, a novel soybean gene encoding a transporter (GmHKT1) was identified and its function analyzed using transgenic plants. GmHKT1 encoded a protein of 419 amino acids, with a potential molecular mass of 47.06 kDa and a predicted pI value of 8.59. Comparison of the genomic and cDNA sequences of GmHKT1 identified no intron. The deduced amino acid sequence of GmHKT1 showed 38-49% identity with other plant HKT-like sequences. RT-PCR analysis showed that the expression of GmHKT1 was upregulated by salt stress (150 mM NaCl) in roots and leaves but not in stems. Overexpression of GmHKT1 significantly enhanced the tolerance of transgenic tobacco plants to salt stress, compared with non-transgenic plants. To investigate the role of GmHKT1 in K(+) and Na(+) transport, we compared K(+) and Na(+) accumulation in roots and shoots of wild-type and transgenic tobacco plants. The results suggested that GmHKT1 is a transporter that affected K(+) and Na(+) transport in roots and shoots, and regulated Na(+) /K(+) homeostasis in these organs. Our findings suggest that GmHKT1 plays an important role in response to salt stress and would be useful in engineering crop plants for enhanced tolerance to salt stress. Copyright © Physiologia Plantarum 2010.
Response of saliva Na/K ratio to changing Na supply of lactating cows under tropical conditions.

PubMed

Thiangtum, Wandee; Schonewille, J Thomas; Verstegen, Martin Wa; Arsawakulsudhi, Supot; Rukkwamsuk, Theera; Hendriks, Wouter H

2017-06-01

Factorial determination of the sodium (Na) requirement of heat-stressed lactating cows is hindered by accurate estimates of the Na losses through sweat. Direct studies, therefore, may be needed requiring information on the time course of healthy animals to become Na depleted and the subsequent rate of repletion. The rate of Na depletion and subsequent rate of Na repletion with two levels of dietary Na to lactating dairy cows housed under tropical conditions were investigated using the salivary Na/K. The 12 lactating cows (salivary Na/K ratio 14.6) rapidly developed clinical signs of Na deficiency, including pica, polyuria and polydipsia, reduced body weight and reduced milk yield when fed a low-Na ration (0.33 g kg -1 dry matter (DM)) for 3 weeks. Deficiency symptoms were associated with a rapid decrease in salivary Na/K ratio to <4.3 from 7 to 21 days. Subsequent repletion of the cows with NaCl to a ration concentration of 1.1 or 1.6 g Na kg -1 DM for 5 weeks did not restore salivary Na/K ratio to values of >6. A daily Na intake of heat-stressed lactating cows to a ration intake of 1.6 g Na kg -1 DM was insufficient to restore Na deficiency. One week was sufficient to deplete heat-stressed lactating cows of Na, allowing for rapid dose-response studies utilizing the salivary Na/K ratio as a parameter for Na status of cows under tropical conditions. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
Co-release of noradrenaline and dopamine in the cerebral cortex elicited by single train and repeated train stimulation of the locus coeruleus

PubMed Central

Devoto, Paola; Flore, Giovanna; Saba, Pierluigi; Fà, Mauro; Gessa, Gian Luigi

2005-01-01

Background Previous studies by our group suggest that extracellular dopamine (DA) and noradrenaline (NA) may be co-released from noradrenergic nerve terminals in the cerebral cortex. We recently demonstrated that the concomitant release of DA and NA could be elicited in the cerebral cortex by electrical stimulation of the locus coeruleus (LC). This study analyses the effect of both single train and repeated electrical stimulation of LC on NA and DA release in the medial prefrontal cortex (mPFC), occipital cortex (Occ), and caudate nucleus. To rule out possible stressful effects of electrical stimulation, experiments were performed on chloral hydrate anaesthetised rats. Results Twenty min electrical stimulation of the LC, with burst type pattern of pulses, increased NA and DA both in the mPFC and in the Occ. NA in both cortices and DA in the mPFC returned to baseline within 20 min after the end of the stimulation period, while DA in the Occ reached a maximum increase during 20 min post-stimulation and remained higher than baseline values at 220 min post-stimulation. Local perfusion with tetrodotoxin (TTX, 10 μM) markedly reduced baseline NA and DA in the mPFC and Occ and totally suppressed the effect of electrical stimulation in both areas. A sequence of five 20 min stimulations at 20 min intervals were delivered to the LC. Each stimulus increased NA to the same extent and duration as the first stimulus, whereas DA remained elevated at the time next stimulus was delivered, so that baseline DA progressively increased in the mPFC and Occ to reach about 130 and 200% the initial level, respectively. In the presence of the NA transport (NAT) blocker desipramine (DMI, 100 μM), multiple LC stimulation still increased extracellular NA and DA levels. Electrical stimulation of the LC increased NA levels in the homolateral caudate nucleus, but failed to modify DA level. Conclusion The results confirm and extend that LC stimulation induces a concomitant release of DA and NA
Evolução temporal da explosão solar de 06 de junho de 2000 apresentando estruturas finas em rádio freqüências

NASA Astrophysics Data System (ADS)

Fernandes, F. C. R.; Sawant, H. S.; Cecatto, J. R.; Caracini, A. G.; Vats, H. O.; Karlický, M.; Meszarosova, H.

2003-08-01

Em 06 de junho de 2000 (~15: 00-17: 00 UT), o Brazilian Solar Spectroscope (BSS) registrou uma explosão solar intensa no intervalo de freqüência de (1000-2000) MHz, com alta resolução temporal (100 ms) e espectral (5 MHz). A atividade solar relacionada a esta explosão associada à região ativa (AR) 9026 e classificada como X2.3 foi grande. O Ondrejov Observatory registrou rádio emissões até 4,5 GHz. O satélite SOHO registrou uma série de erupções solares, incluindo uma Ejeção de Massa Coronal (CME) tipo "full-halo" (~15: 54 UT). Explosões tipo II/IV também foram registradas. Na faixa de ondas decimétricas, este evento apresentou dois picos distintos (~15: 21 UT e ~16: 42 UT). O primeiro pico coincide com a explosão registrada em raios-X moles (GOES) e em raios-X duros (Yohkoh). Os espectros dinâmicos com alta resolução do BSS revelaram várias estruturas finas, principalmente emissões tipo "zebra" e "fibra", rádio pulsações, emissões tipo III e do único caso de emissões "zebra" harmônicas observado na faixa decimétrica. Neste trabalho, analisamos a evolução temporal e o comportamento global do evento de 06 de junho de 2000, com ênfase na identificação e associação da ocorrência de cada tipo de estrutura fina registrada em rádio com cada etapa da explosão. Resultados preliminares mostraram que, na fase pré-flare, as estruturas finas apresentaram taxa de deriva negativa (~ 70-190 MHz/s). As emissões tipo "zebra" concentram-se na fase de descida do primeiro pico impulsivo e na de subida do segundo pico. Enquanto que as emissões tipo "fibra" ocorrem em ambas fases, mas preferivelmente durante a fase de descida. Os resultados serão apresentados e discutidos.
Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

PubMed

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

2016-03-08

The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect
Glutathionylation-Dependence of Na+-K+-Pump Currents Can Mimic Reduced Subsarcolemmal Na+ Diffusion

PubMed Central

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J.; Rasmussen, Helge H.

2016-01-01

The existence of a subsarcolemmal space with restricted diffusion for Na+ in cardiac myocytes has been inferred from a transient peak electrogenic Na+-K+ pump current beyond steady state on reexposure of myocytes to K+ after a period of exposure to K+-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na+ that accumulated in the diffusion-restricted space during pump inhibition in K+-free extracellular solution. However, there are no known physical barriers that account for such restricted Na+ diffusion, and we examined if changes of activity of the Na+-K+ pump itself cause the transient peak current. Reexposure to K+ reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na+ concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K+-free pipette solution could not be reconciled with restricted subsarcolemmal Na+ diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na+- and K+ concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na+-K+ pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na+-K+ pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K+-induced peak Na+-K+ pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K+-induced peak Na+-K+ pump current reflects the effect of conformation-dependent β1 pump subunit
Cytosolic Na+ Controls an Epithelial Na+ Channel Via the Go Guanine Nucleotide-Binding Regulatory Protein

NASA Astrophysics Data System (ADS)

Komwatana, P.; Dinudom, A.; Young, J. A.; Cook, D. I.

1996-07-01

In tight Na+-absorbing epithelial cells, the rate of Na+ entry through amiloride-sensitive apical membrane Na+ channels is matched to basolateral Na+ extrusion so that cell Na+ concentration and volume remain steady. Control of this process by regulation of apical Na+ channels has been attributed to changes in cytosolic Ca2+ concentration or pH, secondary to changes in cytosolic Na+ concentration, although cytosolic Cl- seems also to be involved. Using mouse mandibular gland duct cells, we now demonstrate that increasing cytosolic Na+ concentration inhibits apical Na+ channels independent of changes in cytosolic Ca2+, pH, or Cl-, and the effect is blocked by GDP-β -S, pertussis toxin, and antibodies against the α -subunits of guanine nucleotide-binding regulatory proteins (Go). In contrast, the inhibitory effect of cytosolic anions is blocked by antibodies to inhibitory guanine nucleotide-binding regulatory proteins (Gi1/Gi2. It thus appears that apical Na+ channels are regulated by Go and Gi proteins, the activities of which are controlled, respectively, by cytosolic Na+ and Cl-.
Effect of DA-6 and EDTA alone or in combination on uptake, subcellular distribution and chemical form of Pb in Lolium perenne.

PubMed

He, Shanying; Wu, Qiuling; He, Zhenli

2013-11-01

The effects of growth-promoting hormone diethyl aminoethyl hexanoate (DA-6) and EDTA, either alone or in combination applied to original soil or lead (Pb) spiked soil on Pb phytoextraction, subcellular distribution and chemical forms in Lolium perenne were studied. EDTA addition alone significantly reduced plant biomass though it increased Pb accumulation (P<0.05). Foliar spray of DA-6 alone increased both plant biomass and Pb accumulation (P<0.05), with 10μM DA-6 being the most effective. DA-6 combined with EDTA compensated the adverse effect of the latter on plant growth, and resulted in a synergistic effect on Pb uptake and translocation, with the maximum accumulation occurring in the EDTA+10μM DA-6 treatment. At the subcellular level, about 35-66% of Pb was distributed in cell wall and 21-42% in soluble fraction, with a minority present in cellular organelles fraction. EDTA addition alone increased the proportion of Pb in soluble and cellular organelles fraction, while DA-6 detoxified Pb in plant by storing additional Pb in cell wall, and 10μM DA-6 was the most effective. Of the total Pb in plant shoot, 27-52% was NaCl extractable, 22-47% HAc extractable, followed by other fractions. Contrary to EDTA, DA-6 significantly decreased Pb migration in plant. These results suggest that Pb fixation by pectates and proteins in cell wall and compartmentalization by vacuole might be responsible for Pb detoxification in plant, and the combined use of EDTA and 10μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Pb contaminated soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

Novas determinações dos parâmetros atmosféricos das estrelas anãs brancas DA

NASA Astrophysics Data System (ADS)

Giovannini, O.; Costa, A. F. M.; Kepler, S. O.

2003-08-01

Nós temos selecionado uma amostra de estrelas anãs brancas DA (atmosfera de hidrogênio) a partir dos índices de Strömgren cujos valores estão próximos a região de instabilidade das estrelas anãs brancas DA variáveis, as chamadas estrelas DAV ou ZZ Ceti. O objetivo é determinar os parâmetros fundamentais (temperatura efetiva, Teff, aceleração da gravidade, log g, e massa) destas estrelas para verificar quais os parâmetros estelares estão envolvidos com o mecanismo de pulsação das estrelas DAV. Nós obtemos, até agora, mais de 120 espectros óticos de estrelas DA. Entre as estrelas selecionadas há 20 estrelas variáveis (DAV). Assim, podemos verificar se existem ou não estrelas não variáveis dentro da faixa de instabilidade das estrelas ZZ Ceti. Neste trabalho nós apresentamos a determinação dos parâmetros atmosféricos (temperatura efetiva, Teff, e aceleração da gravidade, log g) das estrelas anãs brancas DA usando os novos modelos de atmosfera ML2/a = 0.6. Estes modelos têm sido utilizados recentemente por fornecerem uma excelente consistência interna na determinação das temperaturas nas regiões do ultra-violeta e ótico. Os parâmetros atmosféricos são determinados espectroscopicamente através da comparação do fluxo de energia das linhas de Balmer (Hb à H9) entre os espectros observados e sintéticos (gerados pelos modelos de atmosfera). As temperaturas obtidas com os novos modelos são, em geral, menores (~ 1000 K menos) que as temperaturas determinadas anteriormente, com modelos ML1. Os valores de log g não mudaram significativamente (menos de 10%). A faixa de instabilidade das DAVs está entre 11000 e 13000 K, consistente com dados de outros autores.
Superconductivity could occur Na-supersaturated NaCl

NASA Astrophysics Data System (ADS)

Hanaki, Koji

1997-04-01

A flow-into electron and a flow-out hole mean flow-into of two unit electric c harges. Even if an exciton consisting of an electron and a hole is a neutral q uasi-particle, overlapping of excitons, namely, the bose condensation changes into a superconductor where half the electric current is due to holes moving t oward the reverse direction. The Meisner effect of the bose condensation comes from the precession of the each exciton under the magnetic field^1. Moreo ver, the present mechanism is supported with that superconducting material alw ays has two kinds of carriers. The superconductivity of NaCl comes from the ab ove-mentioned theory. Free stable holes at first and then electrons are produc ed in NaCl when considerable number of Cl^- lattice vacancies are brought in NaCl mainly because some electrons in the Cl-3p filled band fall into the v acancies. The coexistence of two kinds of stable carriers does not always mean the presence of excitons like VO with electrons not paired and localized in e ach V atom though. While, the absorption spectrum of the NaCl has already conf irmed the presence of excitons; the strength of the spectrum seems to indicate the formation of the bose condensation. Thus we could expect a new supercondu ctor. 1) Hanaki B.Am.P.Soc.,40-1(1995)568
Synergetic effects of DA-6/GA₃ with EDTA on plant growth, extraction and detoxification of Cd by Lolium perenne.

PubMed

He, Shanying; Wu, Qiuling; He, Zhenli

2014-12-01

Research is needed to improve efficiency of phytoextraction of heavy metals from contaminated soils. A pot experiment was carried out to study the effects of plant growth regulators (PGRs) (diethyl aminoethyl hexanoate (C18H33NO8, DA-6) and gibberellic acid 3 (C19H22O6, GA3)) and/or EDTA on Cd extraction, subcellular distribution and chemical forms in Lolium perenne. The addition of EDTA or PGRs significantly enhanced Cd extraction efficiency (P<0.05), with the decreasing order of: 1 μM DA-6>10 μM DA-6>10 μM GA3>2.5 mmol kg(-1) EDTA>other treatments of PGR alone. PGRs+EDTA resulted in a further increase in Cd extraction efficiency, with EDTA+1 μM DA-6 being the most efficient. At the subcellular level, about 44-57% of Cd was soluble fraction, 18-44% in cell walls, and 12-25% in cellular organelles fraction. Chemical speciation analysis showed that 40-54% of Cd was NaCl extractable, 7-23% HAc extractable, followed by other fractions. EDTA increased the proportions of Cd in soluble and cellular organelles fraction, as well as the metal migration in shoot; therefore, the toxicity to plant increased and plant growth was inhibited. Conversely, PGRs fixed more Cd in cell walls and reduced Cd migration in shoot; thus, metal toxicity was reduced. In addition, PGRs promoted plant biomass growth significantly (P<0.05), with 1 μM DA-6 being the most effective. A combination of DA-6/GA3 with EDTA can alleviate the adverse effect of EDTA on plant growth, and the treatment of EDTA+1 μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Cd contaminated soil. Copyright © 2014 Elsevier Ltd. All rights reserved.
DOR activation inhibits anoxic/ischemic Na+ influx through Na+ channels via PKC mechanisms in the cortex.

PubMed

Chao, Dongman; He, Xiaozhou; Yang, Yilin; Bazzy-Asaad, Alia; Lazarus, Lawrence H; Balboni, Gianfranco; Kim, Dong H; Xia, Ying

2012-08-01

Activation of delta-opioid receptors (DOR) is neuroprotective against hypoxic/ischemic injury in the cortex, which is at least partially related to its action against hypoxic/ischemic disruption of ionic homeostasis that triggers neuronal injury. Na(+) influx through TTX-sensitive voltage-gated Na(+) channels may be a main mechanism for hypoxia-induced disruption of K(+) homeostasis, with DOR activation attenuating the disruption of ionic homeostasis by targeting voltage-gated Na(+) channels. In the present study we examined the role of DOR in the regulation of Na(+) influx in anoxia and simulated ischemia (oxygen-glucose deprivation) as well as the effect of DOR activation on the Na(+) influx induced by a Na(+) channel opener without anoxic/ischemic stress and explored a potential PKC mechanism underlying the DOR action. We directly measured extracellular Na(+) activity in mouse cortical slices with Na(+) selective electrodes and found that (1) anoxia-induced Na(+) influx occurred mainly through TTX-sensitive Na(+) channels; (2) DOR activation inhibited the anoxia/ischemia-induced Na(+) influx; (3) veratridine, a Na(+) channel opener, enhanced the anoxia-induced Na(+) influx; this could be attenuated by DOR activation; (4) DOR activation did not reduce the anoxia-induced Na(+) influx in the presence of chelerythrine, a broad-spectrum PKC blocker; and (5) DOR effects were blocked by PKCβII peptide inhibitor, and PKCθ pseudosubstrate inhibitor, respectively. We conclude that DOR activation inhibits anoxia-induced Na(+) influx through Na(+) channels via PKC (especially PKCβII and PKCθ isoforms) dependent mechanisms in the cortex. Copyright © 2012 Elsevier Inc. All rights reserved.
Computational and Experimental Investigations of Na-Ion Conduction in Cubic Na 3PSe 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bo, Shou -Hang; Wang, Yan; Kim, Jae Chul

All-solid-state Na-ion batteries that operate at or close to room temperature are a promising next-generation battery technology with enhanced safety and reduced manufacturing cost. An indispensable component of this technology is the solid-state electrolyte that allows rapid shuttling of the mobile cation (i.e., Na +) between the cathode and anode. However, there are very few fast Na-ion conductors with ionic conductivity approaching that of the liquid counterparts (i.e., 1 mS cm –1). In this work, we present the synthesis and characterization of a fast Na-ion conductor, cubic Na 3PSe 4. This material possesses a room-temperature ionic conductivity exceeding 0.1 mSmore » cm –1 and does not require high-temperature sintering to minimize grain boundary resistance, making it a promising solid-state electrolyte candidate for all-solid-state Na-ion battery applications. On the basis of density functional theory, nudged elastic band, and molecular dynamics investigations, we demonstrate that the framework of cubic Na 3PSe 4 only permits rapid Na + diffusion with the presence of defects, and that the formation of the Na vacancy (charge-balanced by slight Se 2– oxidation) is more energetically favorable among the various defects considered. This finding provides important guidelines to further improve Na-ion conductivity in this class of materials.« less
Computational and Experimental Investigations of Na-Ion Conduction in Cubic Na 3PSe 4

DOE PAGES

Bo, Shou -Hang; Wang, Yan; Kim, Jae Chul; ...

2015-11-17

All-solid-state Na-ion batteries that operate at or close to room temperature are a promising next-generation battery technology with enhanced safety and reduced manufacturing cost. An indispensable component of this technology is the solid-state electrolyte that allows rapid shuttling of the mobile cation (i.e., Na +) between the cathode and anode. However, there are very few fast Na-ion conductors with ionic conductivity approaching that of the liquid counterparts (i.e., 1 mS cm –1). In this work, we present the synthesis and characterization of a fast Na-ion conductor, cubic Na 3PSe 4. This material possesses a room-temperature ionic conductivity exceeding 0.1 mSmore » cm –1 and does not require high-temperature sintering to minimize grain boundary resistance, making it a promising solid-state electrolyte candidate for all-solid-state Na-ion battery applications. On the basis of density functional theory, nudged elastic band, and molecular dynamics investigations, we demonstrate that the framework of cubic Na 3PSe 4 only permits rapid Na + diffusion with the presence of defects, and that the formation of the Na vacancy (charge-balanced by slight Se 2– oxidation) is more energetically favorable among the various defects considered. This finding provides important guidelines to further improve Na-ion conductivity in this class of materials.« less
75 FR 52292 - Airworthiness Directives; Diamond Aircraft Industries GmbH Models DA 40 and DA 40F Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-25

... Industries GmbH Models DA 40 and DA 40F Airplanes AGENCY: Federal Aviation Administration (FAA), Department... new airworthiness directive (AD) for all Diamond Aircraft Industries GmbH Models DA 40 and DA 40F... received information from Diamond Aircraft Industries GmbH that the Models DA 40 and DA 40F airplanes have...
Quasi-solid state rechargeable Na-CO2 batteries with reduced graphene oxide Na anodes.

PubMed

Hu, Xiaofei; Li, Zifan; Zhao, Yaran; Sun, Jianchao; Zhao, Qing; Wang, Jianbin; Tao, Zhanliang; Chen, Jun

2017-02-01

Na-CO 2 batteries using earth-abundant Na and greenhouse gas CO 2 are promising tools for mobile and stationary energy storage, but they still pose safety risks from leakage of liquid electrolyte and instability of the Na metal anode. These issues result in extremely harsh operating conditions of Na-CO 2 batteries and increase the difficulty of scaling up this technology. We report the development of quasi-solid state Na-CO 2 batteries with high safety using composite polymer electrolyte (CPE) and reduced graphene oxide (rGO) Na anodes. The CPE of PVDF-HFP [poly(vinylidene fluoride- co -hexafluoropropylene)]-4% SiO 2 /NaClO 4 -TEGDME (tetraethylene glycol dimethyl ether) has high ion conductivity (1.0 mS cm -1 ), robust toughness, a nonflammable matrix, and strong electrolyte-locking ability. In addition, the rGO-Na anode presents fast and nondendritic Na + plating/stripping (5.7 to 16.5 mA cm -2 ). The improved kinetics and safety enable the constructed rGO-Na/CPE/CO 2 batteries to successfully cycle in wide CO 2 partial pressure window (5 to 100%, simulated car exhaust) and especially to run for 400 cycles at 500 mA g -1 with a fixed capacity of 1000 mA·hour g -1 in pure CO 2 . Furthermore, we scaled up the reversible capacity to 1.1 A·hour in pouch-type batteries (20 × 20 cm, 10 g, 232 Wh kg -1 ). This study makes quasi-solid state Na-CO 2 batteries an attractive prospect.
Quasi–solid state rechargeable Na-CO2 batteries with reduced graphene oxide Na anodes

PubMed Central

Hu, Xiaofei; Li, Zifan; Zhao, Yaran; Sun, Jianchao; Zhao, Qing; Wang, Jianbin; Tao, Zhanliang; Chen, Jun

2017-01-01

Na-CO2 batteries using earth-abundant Na and greenhouse gas CO2 are promising tools for mobile and stationary energy storage, but they still pose safety risks from leakage of liquid electrolyte and instability of the Na metal anode. These issues result in extremely harsh operating conditions of Na-CO2 batteries and increase the difficulty of scaling up this technology. We report the development of quasi–solid state Na-CO2 batteries with high safety using composite polymer electrolyte (CPE) and reduced graphene oxide (rGO) Na anodes. The CPE of PVDF-HFP [poly(vinylidene fluoride-co-hexafluoropropylene)]–4% SiO2/NaClO4–TEGDME (tetraethylene glycol dimethyl ether) has high ion conductivity (1.0 mS cm−1), robust toughness, a nonflammable matrix, and strong electrolyte-locking ability. In addition, the rGO-Na anode presents fast and nondendritic Na+ plating/stripping (5.7 to 16.5 mA cm−2). The improved kinetics and safety enable the constructed rGO-Na/CPE/CO2 batteries to successfully cycle in wide CO2 partial pressure window (5 to 100%, simulated car exhaust) and especially to run for 400 cycles at 500 mA g−1 with a fixed capacity of 1000 mA·hour g−1 in pure CO2. Furthermore, we scaled up the reversible capacity to 1.1 A·hour in pouch-type batteries (20 × 20 cm, 10 g, 232 Wh kg−1). This study makes quasi–solid state Na-CO2 batteries an attractive prospect. PMID:28164158
High-resolution molecular-beam spectroscopy of NaCN and Na 13CN

NASA Astrophysics Data System (ADS)

van Vaals, J. J.; Meerts, W. Leo; Dymanus, A.

The sodium cyanide molecule was studied by molecular-beam electric-resonance spectroscopy in the microwave region. We used the seeded-beam technique to produce a supersonic beam with strong translational, rotational and vibrational cooling. In the frequency range 9.5-40 GHz we observed and identified for NaCN 186 and for Na 13CN 107 hyperfine transitions in 20 and 16 rotational transitions, respectively, all in the ground vibrational state. The rotational, the five quartic and three sextic centrifugal distortion constants of NaCN are: A″ = 57921.954(7) MHz; B″ = 8369.312(2) MHz, C″ = 7272.712(2) MHz. All quadrupole and several spin-rotation coupling constants for the hyperfine interaction were evaluated. The quadrupole coupling constants (in MHz) for NaCN are: eQq12(Na) = -5.344(5), eQq12 = 2.397(7). eQq12(N) = 2.148(4), eQq12(N) = -4.142(5). From these constants and those of Na 13CN we have determined the principal components of the quadrupole coupling tensor for potassium and nitrogen. The structure of sodium cyanide evaluated from the rotational constants of NaCN and Na 13CN was found to be T shaped, similar to the structure of KCN but completely different from the linear isocyanide configuration of LiNC. The effective structural parameters for sodium cyanide in the ground vibrational state are: rCN = 1.170(4) Å, rNaC = 2.379(15) Å, rN12N = 2.233(15) Å, in gratifying agreement with ab initio calculations. Both the geometrical structure and the hyperfine coupling justify the conclusion that the CN group in gaseous sodium cyanide approximately can be considered as a free CN - ion.
Massa do gás e das estrelas em aglomerados: eficiência da formação estelar

NASA Astrophysics Data System (ADS)

Laganá, T. F.; Lima Neto, G. B.

2003-08-01

Os aglomerados de galáxias apresentam um interesse especial para a cosmologia observacional. Eles são as maiores estruturas ligadas pela gravitação no Universo e relaxadas na região central. A comparação entre a massa do gás intra-aglomerado (responsável por ~25% da massa total, inferida a partir de observações em raios-X), a massa contida nas estrelas (i.e., nas galáxias) e a massa total (incluindo a matéria escura não bariônica), nos dá informações importantes sobre os processos de formação e evolução de aglomerados. Por exemplo, a razão entre a massa do gás e a massa total é uma medida da fração de bárions no Universo (razão entre a matéria bariônica e matéria escura) e, utilizando a densidade de bárions predita pela nucleosíntese primordial, podemos deduzir a densidade de matéria escura no Universo (cf. White et al. 1993). O objetivo deste trabalho é obter as razões entre as massas do gás, estelar (contida nas galáxias), e a total (massa dinâmica). As massas do gás e total são obtidas a partir das análises fotométrica e espectroscópica em raios-X enquanto que a massa estelar é obtida pela análise fotométrica das galáxias. Esta análise foi aplicada ao aglomerado Abell 496 observado pelo satélite XMM-Newton. A massa contida nas galáxias foi estimada a partir da função de luminosidade obtida por Durret et al. (2002). Para determinar as massas dinâmica e do gás nos precisamos determinar os perfis radiais de densidade e temperatura. Nós apresentaremos aqui estes resultados e suas implicações na eficiência da formação estelar em Abell 496.
Synthesis of zeolites Na-A and Na-X from tablet compressed and calcinated coal fly ash

NASA Astrophysics Data System (ADS)

Hu, Tao; Gao, Wenyan; Liu, Xin; Zhang, Yifu; Meng, Changgong

2017-10-01

Zeolites Na-A and Na-X are important synthetic zeolites widely used for separation and adsorption in industry. It is of great significance to develop energy-efficient routines that can synthesize zeolites Na-A and Na-X from low-cost raw materials. Coal fly ash (CFA) is the major residue from the combustion of coal and biomass containing more than 85% SiO2 and Al2O3, which can readily replace the conventionally used sodium silicate and aluminate for zeolite synthesis. We used Na2CO3 to replace the expensive NaOH used for the calcination of CFA and showed that tablet compression can enhance the contact with Na2CO3 for the activation of CFA through calcination for the synthesis of zeolites Na-A and Na-X under mild conditions. We optimized the control variables for zeolite synthesis and showed that phase-pure zeolite Na-A can be synthesized with CFA at reactant molar ratio, hydrothermal reaction temperature and reaction time of 1.3Na2O: 0.6Al2O3: 1SiO2: 38H2O at 80°C for 6 h, respectively, while phase-pure zeolite Na-X can be synthesized at 2.2Na2O: 0.2Al2O3: 1SiO2: 88H2O at 100°C for 8 h, respectively. The composition, morphology, specific surface area, vibration spectrum and thermogravimetry of synthesized Na-A and Na-X were further characterized.
Structural and Na-ion conduction characteristics of Na 3 PS x Se 4-x

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bo, Shou-Hang; Wang, Yan; Ceder, Gerbrand

The recent discovery of the isostructrual cubic Na 3PS 4 and Na 3PSe 4 as fast Na-ion conductors provided a general structural framework for the exploration of new sodium superionic conductors. In this work, we systematically investigated the structures and ionic conduction characteristics of a series of compounds with the general chemical formula of Na 3PS xSe 4-x. Synthesis of Na 3PS 4 under different conditions (e.g., temperature, reaction vessel, mass of the precursors) reveals the reactivity of the precursors with the reaction tubes, producing different polymorphs. X-ray diffraction studies on the solid solution phases Na 3PS xSe 4-x more » identified a tetragonal-to-cubic phase transition with increasing Se concentration. This observation is consistent with the computed stability of the tetragonal and cubic polymorphs, where the energy difference between the two polymorphs becomes very close to zero in Se-rich compositions. Furthermore, ab initio molecular dynamic simulations suggest that the fast Na-ion conduction in Na 3PS xSe 4-x may not be causally related with the symmetry or the composition of these phases. The formation of defects, instead, enables fast Na-ion conduction in this class of materials.« less
Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin

PubMed Central

Sato, Yuichiro; Morimoto, Kinjiro; Kubo, Takanori; Sakaguchi, Takemasa; Nishizono, Akira; Hirayama, Makoto; Hori, Kanji

2015-01-01

Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009) was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM)-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC50 of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC50s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells. PMID:26035023
Formation of Si grains from a NaSi melt prepared by reaction of SiO2 and Na

NASA Astrophysics Data System (ADS)

Yamane, Hisanori; Morito, Haruhiko; Uchikoshi, Masahito

2013-08-01

A mixture of Na2SiO3 and NaSi was found to be formed by reaction of SiO2 and Na at 650 °C as follows: 5Na+3SiO2→2Na2SiO3+NaSi. Single crystals of NaSi were grown by cooling the mixture of Na2SiO3 and NaSi with an excess amount of Na from 850 °C, and polycrystalline Si was obtained by vaporization of Na from the crystals. Coarse grains of Si were also crystallized by Na evaporation after the formation of Na2SiO3 and Si-dissolved liquid Na at 830 °C. The Si grains were collected by washing the product with water. The yield of the Si grains was 85% of the ideal amount expected from the reaction.
Sexual odor preference and dopamine release in the nucleus accumbens by estrous olfactory cues in sexually naïve and experienced male rats.

PubMed

Fujiwara, Masaya; Chiba, Atsuhiko

2018-03-01

Sexual behavior is a natural reward that activates mesolimbic dopaminergic system. Microdialysis studies have shown that extracellular level of dopamine (DA) in the nucleus accumbens (NAcc) significantly increases during copulation in male rats. The NAcc DA level is also known to be increased during the presentation of a sexually receptive female before mating. This rise in DA was probably associated with sexual motivation elicited by incentive stimuli from the receptive female. These microdialysis studies, however, did not thoroughly investigated if olfactory stimuli from estrous females could significantly increase the extracellular DA in the NAcc of male rats. The present study was designed to examine systematically the relationship between the expression of preference for the olfactory stimuli from estrous females and the effects of these stimuli on the extracellular DA levels in the NAcc measured by in vivo microdialysis in male Long-Evans (LE) rats. We used two types of olfactory stimuli, either airborne odors (volatile stimuli) or soiled bedding (volatile plus nonvolatile stimuli). The sexually experienced male rats, which experienced six ejaculations, significantly preferred both of these olfactory stimuli from estrous females as opposed to males. Exposure to these female olfactory stimuli gradually increased extracellular DA in the NAcc, which reached significantly higher level above baseline during the period following the removal of the stimuli although not during the 15-min stimulus presentation period. The sexually naïve male rats, on the other hand, showed neither preference for olfactory stimuli from estrous females nor increase in the NAcc DA after exposure to these stimuli. These data suggest that in male LE rats olfactory stimuli from estrous females in and of themselves can be conditional cues that induce both incentive motivation and a significant increase in the NAcc DA probably as a result of being associated with sexual reward through
The relative viscosity of NaNO 3 and NaNO 2 aqueous solutions

DOE PAGES

Reynolds, Jacob G.; Mauss, Billie M.; Daniel, Richard C.

2018-05-09

In aqueous solution, both nitrate and nitrite are planar, monovalent, and have the same elements but different sizes and charge densities. Comparing the viscosity of NaNO 2 and NaNO 3 aqueous solutions provides an opportunity to determine the relative importance of anion size versus strength of anion interaction with water. The viscosity of aqueous NaNO 2 and NaNO 3 were measured over a temperature and concentration range relevant to nuclear waste processing. The viscosity of NaNO 2 solutions was consistently larger than NaNO 3 under all conditions, even though nitrate is larger than nitrite. This was interpreted in terms ofmore » quantum mechanical charge field molecular dynamics calculations that indicate that nitrite forms more and stronger hydrogen bonds with water per oxygen atom than nitrate. Furthermore, these hydrogen bonds inhibit rotational motion required for fluid flow, thus increasing the nitrite solution viscosity relative to that of an equivalent nitrate solution.« less
The relative viscosity of NaNO 3 and NaNO 2 aqueous solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reynolds, Jacob G.; Mauss, Billie M.; Daniel, Richard C.

In aqueous solution, both nitrate and nitrite are planar, monovalent, and have the same elements but different sizes and charge densities. Comparing the viscosity of NaNO 2 and NaNO 3 aqueous solutions provides an opportunity to determine the relative importance of anion size versus strength of anion interaction with water. The viscosity of aqueous NaNO 2 and NaNO 3 were measured over a temperature and concentration range relevant to nuclear waste processing. The viscosity of NaNO 2 solutions was consistently larger than NaNO 3 under all conditions, even though nitrate is larger than nitrite. This was interpreted in terms ofmore » quantum mechanical charge field molecular dynamics calculations that indicate that nitrite forms more and stronger hydrogen bonds with water per oxygen atom than nitrate. Furthermore, these hydrogen bonds inhibit rotational motion required for fluid flow, thus increasing the nitrite solution viscosity relative to that of an equivalent nitrate solution.« less
Molecular and functional differences in voltage-activated sodium currents between GABA projection neurons and dopamine neurons in the substantia nigra

PubMed Central

Ding, Shengyuan; Wei, Wei

2011-01-01

GABA projection neurons (GABA neurons) in the substantia nigra pars reticulata (SNr) and dopamine projection neurons (DA neurons) in substantia nigra pars compacta (SNc) have strikingly different firing properties. SNc DA neurons fire low-frequency, long-duration spikes, whereas SNr GABA neurons fire high-frequency, short-duration spikes. Since voltage-activated sodium (NaV) channels are critical to spike generation, the different firing properties raise the possibility that, compared with DA neurons, NaV channels in SNr GABA neurons have higher density, faster kinetics, and less cumulative inactivation. Our quantitative RT-PCR analysis on immunohistochemically identified nigral neurons indicated that mRNAs for pore-forming NaV1.1 and NaV1.6 subunits and regulatory NaVβ1 and Navβ4 subunits are more abundant in SNr GABA neurons than SNc DA neurons. These α-subunits and β-subunits are key subunits for forming NaV channels conducting the transient NaV current (INaT), persistent Na current (INaP), and resurgent Na current (INaR). Nucleated patch-clamp recordings showed that INaT had a higher density, a steeper voltage-dependent activation, and a faster deactivation in SNr GABA neurons than in SNc DA neurons. INaT also recovered more quickly from inactivation and had less cumulative inactivation in SNr GABA neurons than in SNc DA neurons. Furthermore, compared with nigral DA neurons, SNr GABA neurons had a larger INaR and INaP. Blockade of INaP induced a larger hyperpolarization in SNr GABA neurons than in SNc DA neurons. Taken together, these results indicate that NaV channels expressed in fast-spiking SNr GABA neurons and slow-spiking SNc DA neurons are tailored to support their different spiking capabilities. PMID:21880943
Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

NASA Technical Reports Server (NTRS)

Cherng, Jing-Yih; Bennion, Douglas N.

1987-01-01

A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

On the Origin of Cortical Dopamine: Is it a Co-Transmitter in Noradrenergic Neurons?

PubMed Central

Devoto, Paola; Flore, Giovanna

2006-01-01

Dopamine (DA) and noradrenaline (NA) in the prefrontal cortex (PFC) modulate superior cognitive functions, and are involved in the aetiology of depressive and psychotic symptoms. Moreover, microdialysis studies in rats have shown how pharmacological treatments that induce modifications of extracellular NA in the medial PFC (mPFC), also produce parallel changes in extracellular DA. To explain the coupling of NA and DA changes, this article reviews the evidence supporting the hypothesis that extracellular DA in the cerebral cortex originates not only from dopaminergic terminals but also from noradrenergic ones, where it acts both as precursor for NA and as a co-transmitter. Accordingly, extracellular DA concentration in the occipital, parietal and cerebellar cortex was found to be much higher than expected in view of the scarce dopaminergic innervation in these areas. Systemic administration or intra-cortical perfusion of α2-adrenoceptor agonists and antagonists, consistent with their action on noradrenergic neuronal activity, produced concomitant changes not only in extracellular NA but also in DA in the mPFC, occipital and parietal cortex. Chemical modulation of the locus coeruleus by locally applied carbachol, kainate, NMDA or clonidine modified both NA and DA in the mPFC. Electrical stimulation of the locus coeruleus led to an increased efflux of both NA and DA in mPFC, parietal and occipital cortex, while in the striatum, NA efflux alone was enhanced. Atypical antipsychotics, such as clozapine and olanzapine, or antidepressants, including mirtazapine and mianserine, have been found to increase both NA and DA throughout the cerebral cortex, likely through blockade of α2-adrenoceptors. On the other hand, drugs selectively acting on dopaminergic transmission produced modest changes in extracellular DA in mPFC, and had no effect on the occipital or parietal cortex. Acute administration of morphine did not increase DA levels in the PFC (where NA is diminished), in
On the origin of cortical dopamine: is it a co-transmitter in noradrenergic neurons?

PubMed

Devoto, Paola; Flore, Giovanna

2006-04-01

Dopamine (DA) and noradrenaline (NA) in the prefrontal cortex (PFC) modulate superior cognitive functions, and are involved in the aetiology of depressive and psychotic symptoms. Moreover, microdialysis studies in rats have shown how pharmacological treatments that induce modifications of extracellular NA in the medial PFC (mPFC), also produce parallel changes in extracellular DA.To explain the coupling of NA and DA changes, this article reviews the evidence supporting the hypothesis that extracellular DA in the cerebral cortex originates not only from dopaminergic terminals but also from noradrenergic ones, where it acts both as precursor for NA and as a co-transmitter.Accordingly, extracellular DA concentration in the occipital, parietal and cerebellar cortex was found to be much higher than expected in view of the scarce dopaminergic innervation in these areas.Systemic administration or intra-cortical perfusion of alpha(2)-adrenoceptor agonists and antagonists, consistent with their action on noradrenergic neuronal activity, produced concomitant changes not only in extracellular NA but also in DA in the mPFC, occipital and parietal cortex.Chemical modulation of the locus coeruleus by locally applied carbachol, kainate, NMDA or clonidine modified both NA and DA in the mPFC.Electrical stimulation of the locus coeruleus led to an increased efflux of both NA and DA in mPFC, parietal and occipital cortex, while in the striatum, NA efflux alone was enhanced.Atypical antipsychotics, such as clozapine and olanzapine, or antidepressants, including mirtazapine and mianserine, have been found to increase both NA and DA throughout the cerebral cortex, likely through blockade of alpha(2)-adrenoceptors. On the other hand, drugs selectively acting on dopaminergic transmission produced modest changes in extracellular DA in mPFC, and had no effect on the occipital or parietal cortex.Acute administration of morphine did not increase DA levels in the PFC (where NA is diminished
NA62 and NA48/2 results on search for Heavy Neutral Leptons

NASA Astrophysics Data System (ADS)

Lamanna, Gianluca; Aliberti, R.; Ambrosino, F.; Ammendola, R.; Angelucci, B.; Antonelli, A.; Anzivino, G.; Arcidiacono, R.; Barbanera, M.; Biagioni, A.; Bician, L.; Biino, C.; Bizzeti, A.; Blazek, T.; Bloch-Devaux, B.; Bonaiuto, V.; Boretto, M.; Bragadireanu, M.; Britton, D.; Brizioli, F.; Brunetti, M. B.; Bryman, D.; Bucci, F.; Capussela, T.; Ceccucci, A.; Cenci, P.; Cerny, V.; Cerri, C.; Checcucci, B.; Conovaloff, A.; Cooper, P.; Cortina Gil, E.; Corvino, M.; Costantini, F.; Cotta Ramusino, A.; Coward, D.; D'Agostini, G.; Dainton, J.; Dalpiaz, P.; Danielsson, H.; De Simone, N.; Di Filippo, D.; Di Lella, L.; Doble, N.; Dobrich, B.; Duval, F.; Duk, V.; Engelfried, J.; Enik, T.; Estrada-Tristan, N.; Falaleev, V.; Fantechi, R.; Fascianelli, V.; Federici, L.; Fedotov, S.; Filippi, A.; Fiorini, M.; Fry, J.; Fu, J.; Fucci, A.; Fulton, L.; Gamberini, E.; Gatignon, L.; Georgiev, G.; Ghinescu, S.; Gianoli, A.; Giorgi, M.; Giudici, S.; Gonnella, F.; Goudzovski, E.; Graham, C.; Guida, R.; Gushchin, E.; Hahn, F.; Heath, H.; Husek, T.; Hutanu, O.; Hutchcroft, D.; Iacobuzio, L.; Iacopini, E.; Imbergamo, E.; Jenninger, B.; Kampf, K.; Kekelidze, V.; Kholodenko, S.; Khoriauli, G.; Khotyantsev, A.; Kleimenova, A.; Korotkova, A.; Koval, M.; Kozhuharov, V.; Kucerova, Z.; Kudenko, Y.; Kunze, J.; Kurochka, V.; Kurshetsov, V.; Lanfranchi, G.; Lamanna, G.; Latino, G.; Laycock, P.; Lazzeroni, C.; Lenti, M.; Lehmann Miotto, G.; Leonardi, E.; Lichard, P.; Litov, L.; Lollini, R.; Lomidze, D.; Lonardo, A.; Lubrano, P.; Lupi, M.; Lurkin, N.; Madigozhin, D.; Mannelli, I.; Mannocchi, G.; Mapelli, A.; Marchetto, F.; Marchevski, R.; Martellotti, S.; Massarotti, P.; Massri, K.; Maurice, E.; Medvedeva, M.; Mefodev, A.; Menichetti, E.; Migliore, E.; Minucci, E.; Mirra, M.; Misheva, M.; Molokanova, N.; Moulson, M.; Movchan, S.; Napolitano, M.; Neri, I.; Newson, F.; Norton, A.; Noy, M.; Numao, T.; Obraztsov, V.; Ostankov, A.; Padolski, S.; Page, R.; Palladino, V.; Parkinson, C.; Pedreschi, E.; Pepe, M.; Perrin-Terrin, M.; Peruzzo, L.; Petrov, P.; Petrucci, F.; Piandani, R.; Piccini, M.; Pinzino, J.; Polenkevich, I.; Pontisso, L.; Potrebenikov, Yu.; Protopopescu, D.; Raggi, M.; Romano, A.; Rubin, P.; Ruggiero, G.; Ryjov, V.; Salamon, A.; Santoni, C.; Saracino, G.; Sargeni, F.; Semenov, V.; Sergi, A.; Shaikhiev, A.; Shkarovskiy, S.; Soldi, D.; Sougonyaev, V.; Sozzi, M.; Spadaro, T.; Spinella, F.; Sturgess, A.; Swallow, J.; Trilov, S.; Valente, P.; Velghe, B.; Venditti, S.; Vicini, P.; Volpe, R.; Vormstein, M.; Wahl, H.; Wanke, R.; Wrona, B.; Yushchenko, O.; Zamkovsky, M.; Zinchenko, A.

2018-05-01

In this paper we present new results on upper limits for the search of Heavy Neutral Leptons (HNL) with data collected by NA48/2 (2003-2004), NA62-RK (2007) and NA62 (2015) CERN experiments. The data collected with different trigger configuration allow to search for both long and short living heavy neutrinos in the mass range below the kaon mass. In addition the status of the search for K+ → π+vv with the NA62 detector will be briefly presented.
Vacancy-Controlled Na+ Superion Conduction in Na11 Sn2 PS12.

PubMed

Duchardt, Marc; Ruschewitz, Uwe; Adams, Stefan; Dehnen, Stefanie; Roling, Bernhard

2018-01-26

Highly conductive solid electrolytes are crucial to the development of efficient all-solid-state batteries. Meanwhile, the ion conductivities of lithium solid electrolytes match those of liquid electrolytes used in commercial Li + ion batteries. However, concerns about the future availability and the price of lithium made Na + ion conductors come into the spotlight in recent years. Here we present the superionic conductor Na 11 Sn 2 PS 12 , which possesses a room temperature Na + conductivity close to 4 mS cm -1 , thus the highest value known to date for sulfide-based solids. Structure determination based on synchrotron X-ray powder diffraction data proves the existence of Na + vacancies. As confirmed by bond valence site energy calculations, the vacancies interconnect ion migration pathways in a 3D manner, hence enabling high Na + conductivity. The results indicate that sodium electrolytes are about to equal the performance of their lithium counterparts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Noradrenaline and dopamine levels in acute cerveau isolé in the cat.

PubMed

Szikszay, M; Benedek, G; Obál, F; Obál, F

1980-01-01

Noradrenaline (NA) and dopamine (DA) levels were studied in the forebrain of acute immobilized cats and in cerveau isolé preparations. A gradual decrease in NA and DA was observed one and two hours after high mesencephalic transection, while the amount of NA increased in acute immobilized cats after the cessation of ether anaesthesia. These changes in NA level are consistent with the observations suggesting an inverse relationship between NA and cortical deactivation. The decrease of DA with an exaggeration of spindle activity and increased synchronizing effect of basal forebrain stimulation indicate that the spindle-increasing effect of DA suggested by several authors requires the contribution of the brain stem.
Experimental and first-principles study of photoluminescent and optical properties of Na-doped CuAlO2: the role of the NaAl-2Na i complex

NASA Astrophysics Data System (ADS)

Liu, Ruijian; Li, Yongfeng; Yao, Bin; Ding, Zhanhui; Deng, Rui; Zhang, Ligong; Zhao, Haifeng; Liu, Lei

2015-08-01

We report that a band-tail emission at 3.08 eV, lower than near-band-edge energy, is observed in photoluminescence measurements of bulk Na-doped CuAlO2. The band-tail emission is attributed to Na-related defects. Electronic structure calculations based on the first-principles method demonstrate that the donor-acceptor compensated complex of NaAl-2Na i in Na-doped CuAlO2 plays a key role in leading to the band-tail emission and bandgap narrowing. Furthermore, Hall effect measurements indicates that the hole concentration in CuAlO2 is independent on Na doping, which is well understood by the donor-acceptor compensation effect of NaAl-2Na i complex.
Da Vinci-assisted abdominal cerclage.

PubMed

Barmat, Larry; Glaser, Gretchen; Davis, George; Craparo, Frank

2007-11-01

To report the first placement of an abdominal cervicoisthmic cerclage using the da Vinci robot. Case report. Tertiary-care hospital. A 39-year-old female with a history of cervical insufficiency who required a cerclage and was not a candidate for transvaginal cerclage placement. Abdominal cervicoisthmic cerclage placement using the da Vinci robot. Ability to safely and successfully place an abdominal cerclage using the da Vinci robot. Abdominal cerclage was successfully placed using the da Vinci robot. The patient had minimal blood loss and was discharged to home on the same day as surgery. Da Vinci robot-assisted abdominal cerclage placement is an innovative application of robotic surgery and may alter the standard of care for women who require this surgery.
Lithostratigraphy and volcanology of the Serra Geral Group, Paraná-Etendeka Igneous Province in Southern Brazil: Towards a formal stratigraphical framework

NASA Astrophysics Data System (ADS)

Rossetti, Lucas; Lima, Evandro F.; Waichel, Breno L.; Hole, Malcolm J.; Simões, Matheus S.; Scherer, Claiton M. S.

2018-04-01

The volcanic rocks of the Lower Cretaceous Paraná-Etendeka Igneous Province, in Brazil, are grouped in the Serra Geral Group. The province can be chemically divided into low-TiO2, and high-TiO2. In southern Brazil, the low-TiO2 lava pile reaches a thickness of 1 km and is formed of heterogeneous lava packages here divided into four lava formations. Torres Formation (TF) is characterized by chemically more primitive basaltic (> 5 wt% MgO) compound pahoehoe flow fields; these lavas stratigraphically overly aeolian sandstones of Botucatu Formation and represent the onset of the volcanic activity. Vale do Sol Formation (VSF) groups vertically stacked sheet-like rubbly pahoehoe basaltic andesites (SiO2 > 51 wt%; MgO < 5 wt%). These lavas covered the former basalts in the Torres Syncline axis and pinch out towards southwest and represent the most voluminous mafic lava flows. Dacites and rhyolites of Palmas Formation (PF) overlay VSF flows in the central and eastern outcrop area and rest directly upon TF lavas in the west. The acidic units were emplaced as lava domes and widespread tabular lava flows. Esmeralda Formation (EF) is the upper stratigraphic unit and it is formed by a basaltic pahoehoe flow field emplaced during the waning phase of volcanic activity of the low-TiO2 lava sequence. Sedimentary interbeds are preserved throughout the whole lava pile and were deposited during quiescence periods of volcanic activity, and represent important stratigraphic markers (e.g. TF-VSF contact). The newly proposed stratigraphy provides promptly recognized stratigraphic units in a regional framework of fundamental importance for future correlations and provide vital information in the understanding of how the Paraná-Etendeka Igneous Province evolved through time.
Structural and Na-ion conduction characteristics of Na 3PS xSe 4–x

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bo, Shou -Hang; Wang, Yan; Ceder, Gerbrand

The recent discovery of the isostructrual cubic Na 3PS 4 and Na 3PSe 4 as fast Na-ion conductors provided a general structural framework for the exploration of new sodium superionic conductors. In this work, we systematically investigated the structures and ionic conduction characteristics of a series of compounds with the general chemical formula of Na 3PS xSe 4–x. Synthesis of Na 3PS 4 under different conditions (e.g., temperature, reaction vessel, mass of the precursors) reveals the reactivity of the precursors with the reaction tubes, producing different polymorphs. X-ray diffraction studies on the solid solution phases Na 3PS xSe 4–x identifiedmore » a tetragonal-to-cubic phase transition with increasing Se concentration. This observation is consistent with the computed stability of the tetragonal and cubic polymorphs, where the energy difference between the two polymorphs becomes very close to zero in Se-rich compositions. Furthermore, ab initio molecular dynamic simulations suggest that the fast Na-ion conduction in Na 3PS xSe 4–x may not be causally related with the symmetry or the composition of these phases. The formation of defects, instead, enables fast Na-ion conduction in this class of materials.« less
Structural and Na-ion conduction characteristics of Na 3PS xSe 4–x

DOE PAGES

Bo, Shou -Hang; Wang, Yan; Ceder, Gerbrand

2016-05-19

The recent discovery of the isostructrual cubic Na 3PS 4 and Na 3PSe 4 as fast Na-ion conductors provided a general structural framework for the exploration of new sodium superionic conductors. In this work, we systematically investigated the structures and ionic conduction characteristics of a series of compounds with the general chemical formula of Na 3PS xSe 4–x. Synthesis of Na 3PS 4 under different conditions (e.g., temperature, reaction vessel, mass of the precursors) reveals the reactivity of the precursors with the reaction tubes, producing different polymorphs. X-ray diffraction studies on the solid solution phases Na 3PS xSe 4–x identifiedmore » a tetragonal-to-cubic phase transition with increasing Se concentration. This observation is consistent with the computed stability of the tetragonal and cubic polymorphs, where the energy difference between the two polymorphs becomes very close to zero in Se-rich compositions. Furthermore, ab initio molecular dynamic simulations suggest that the fast Na-ion conduction in Na 3PS xSe 4–x may not be causally related with the symmetry or the composition of these phases. The formation of defects, instead, enables fast Na-ion conduction in this class of materials.« less
A thermochemical explanation for the stability of NaCl3 and NaCl7

NASA Astrophysics Data System (ADS)

Fernandes de Farias, Robson

2017-03-01

Thermodynamically stable cubic and orthorhombic NaCl3 as well as NaCl7 have been synthesized (Zhang et al., 2013). In the present work, a thermochemical explanation for the stability of such unusual sodium chlorides is provided, based on lattice energy values. Using the Glasser-Jenkins generalized equation (Glasser and Jenkins, 2000) lattice energies (kJ mol-1) of -162.5, -168.9 and -113.1 are calculated for Pm3n NaCl3, Pnma NaCl3 and NaCl7, respectively. It is postulated that any NaxCly compound could be synthesized, if the ionic character of the Nasbnd Cl bond in the prepared compound remains around 80%, and the sodium charge below unit.
Diffusive emission of methane and carbon dioxide from two hydropower reservoirs in Brazil.

PubMed

Marcelino, A A; Santos, M A; Xavier, V L; Bezerra, C S; Silva, C R O; Amorim, M A; Rodrigues, R P; Rogerio, J P

2015-05-01

The role of greenhouse gas emissions from freshwater reservoirs and their contribution to increase greenhouse gas concentrations in the atmosphere is currently under discussion in many parts of the world. We studied CO2 and CH4 diffusive fluxes from two large neotropical hydropower reservoirs with different climate conditions. We used floating closed-chambers to estimate diffusive fluxes of these gaseous species. Sampling campaigns showed that the reservoirs studied were sources of greenhouse gases to the atmosphere. In the Serra da Mesa Reservoir, the CH4 emissions ranged from 0.530 to 396.96 mg.m(-2).d(-1) and CO2 emissions ranged from -1,738.33 to 11,166.61 mg.m(-2).d(-1) and in Três Marias Reservoir the CH4 fluxes ranged 0.720 to 2,578.03 mg.m(-2).d(-1) and CO2 emission ranged from -3,037.80 to 11,516.64 to mg.m(-2).d(-1). There were no statistically significant differences of CH4 fluxes between the reservoirs, but CO2 fluxes from the two reservoirs studied were significantly different. The CO2 emissions measured over the periods studied in Serra da Mesa showed some seasonality with distinctions between the wet and dry transition season. In Três Marias Reservoir the CO2 fluxes showed no seasonal variability. In both reservoirs, CH4 emissions showed a tendency to increase during the study periods but this was not statistically significant. These results contributed to increase knowledge about the magnitude of CO2 and CH4 emission in hydroelectric reservoirs, however due to natural variability of the data future sampling campaigns will be needed to better elucidate the seasonal influences on the fluxes of greenhouse gases.
On Ensino de Astronomia: Desafios para Implantação

NASA Astrophysics Data System (ADS)

Faria, R. Z.; Voelzke, M. R.

2008-09-01

Em 2002 o ensino de Astronomia foi proposto como um dos temas estruturadores pelos Parâmetros Curriculares Nacionais e sugerido como facilitador para que o aluno compreendesse a Física como construção humana e parte do seu mundo vivencial, mas raramente seus conceitos foram ensinados. A presente pesquisa discute dois aspectos relacionados à abordagem de Astronomia. O primeiro aspecto é se ela está sendo abordada pelos professores do Ensino Médio e o segundo, aborda a maneira como ela está sendo ensinada. Optou-se pela aplicação de um questionário a partir do 2° semestre de 2006 e durante o ano de 2007 com professores que ministram a disciplina de Física, os quais trabalham em escolas estaduais em Rio Grande da Serra, Ribeirão Pires e Mauá no estado São Paulo. Dos 66,2% dos professores que responderam ao questionário nos municípios de Rio Grande da Serra, Ribeirão Pires e Mauá, 57,4% não aplicaram nenhum tópico de astronomia, 70,2% não utilizaram laboratório, 89,4% não utilizaram qualquer tipo de programa computacional, 83,0% nunca fizeram visitas com alunos a museus e planetários e 38,3% não indicaram qualquer tipo de livro ou revista referente à astronomia aos seus alunos. Mesmo considerando a Astronomia um conteúdo potencialmente significativo, esta não fez parte dos planejamentos escolares. Portanto são necessárias propostas que visem estratégias para a educação continuada dos professores como, por exemplo, cursos específicos sobre o ensino em Astronomia.
The impact of AMO and NAO in Western Iberia during the Late Holocene

NASA Astrophysics Data System (ADS)

Hernandez, A.; Leira, M.; Trigo, R.; Vázquez-Loureiro, D.; Carballeira, R.; Sáez, A.

2016-12-01

High mountain lakes in the Iberian Peninsula are particularly sensitive to the influence of North Atlantic large-scale modes of climate variability due to their geographical position and the reduced anthropic disturbances. In this context, Serra da Estrela (Portugal), the westernmost range of the Sistema Central, constitutes a physical barrier to air masses coming from the Atlantic Ocean. However, long-term climate reconstructions have not yet been conducted. We present a climate reconstruction of this region based on facies analysis, X-ray fluorescence core scanning, elemental and isotope geochemistry on bulk organic matter and a preliminary study of diatom assemblages from the sedimentary record of Lake Peixão (1677 m a.s.l.; Serra da Estrela) for the last ca. 3500 years. A multivariate statistical analysis has been performed to recognize the main environmental factors controlling the sedimentary infill. Our results reveal that two main processes explain the 70% of the total variance. Thus, changes in primary productivity, reflected in organic matter accumulation, and variations in runoff, related to external particles input, explain 53% and 17% respectively. Additionally, evidence of changes in productivity and water level regime recorded as variations in diatom assemblages correlate well with our interpretations. A comparison between the lake productivity changes and previous Atlantic Multidecadal Oscillation (AMO) reconstructions shows a good correlation, suggesting this climate mode as the main driver over lacustrine primary productivity at multi-decadal scales. In turn, changes in terrigenous inputs, linked to precipitation, seem to be more influenced by the winter North Atlantic Oscillation (NAO) variability. Hence, our results highlight that although the climate regime in this area is clearly influenced by the NAO, the AMO also plays a key role at long-term time-scales.
Prevalence of asthma in children and adolescents in a city in the Brazilian Amazon region.

PubMed

Rosa, Antonia Maria; Ignotti, Eliane; Hacon, Sandra de Souza; Castro, Hermano Albuquerque de

2009-01-01

To analyze the prevalence of asthma and asthma symptoms in students of two distinct age brackets residing in the city of Tangará da Serra, Brazil. Cross-sectional, population-based study of the prevalence of asthma in children from 6 to 7 years of age and adolescents from 13 to 14, using the standardized International Study of Asthma and Allergies in Childhood, phase 1 questionnaire, validated for use in Brazil. Students who responded affirmatively to question 2 (presence of wheezing in the preceding 12 months) were classified as suffering from asthma. The study comprised 3,362 students, of whom 1,634 (48.6%) were children and 1,728 (51.4%) were adolescents. Of the 1,634 children, 816 (49.9%) were male, and 818 (50.1%) were female. Of the 1,728 adolescents, 773 (45.0%) were male, and 955 (55.0%) were female. The prevalence of asthma among the children was 25.2%, whereas that among the adolescents was 15.9% (chi2 = 8.34; p = 0.00). The children presented higher prevalences of the following symptoms of asthma than did the adolescents: wheezing ever (54.3%), nocturnal dry cough (43.9%), wheezing in the preceding 12 months (25.2%), and from 1 to 3 attacks of wheezing in the preceding 12 months (19.1%). There were no differences between the two groups regarding physician-diagnosed asthma (approximately 4.5%). There were no statistical differences regarding the prevalence of asthma by gender in the two groups. Tangará da Serra has a high prevalence of asthma in children and adolescents, and this result is compatible with other studies carried out in Brazil and Latin America using the same methodology.
Long range intermolecular interactions between the alkali diatomics Na2, K2, and NaK

NASA Astrophysics Data System (ADS)

Zemke, Warren T.; Byrd, Jason N.; Michels, H. Harvey; Montgomery, John A.; Stwalley, William C.

2010-06-01

Long range interactions between the ground state alkali diatomics Na2-Na2, K2-K2, Na2-K2, and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies. A simple asymptotic model potential ELR=Eelec+Edisp+Eind is shown to accurately represent the intermolecular interactions for these systems at long range.
Route, mechanism, and implications of proton import during Na+/K+ exchange by native Na+/K+-ATPase pumps

PubMed Central

Vedovato, Natascia

2014-01-01

A single Na+/K+-ATPase pumps three Na+ outwards and two K+ inwards by alternately exposing ion-binding sites to opposite sides of the membrane in a conformational sequence coupled to pump autophosphorylation from ATP and auto-dephosphorylation. The larger flow of Na+ than K+ generates outward current across the cell membrane. Less well understood is the ability of Na+/K+ pumps to generate an inward current of protons. Originally noted in pumps deprived of external K+ and Na+ ions, as inward current at negative membrane potentials that becomes amplified when external pH is lowered, this proton current is generally viewed as an artifact of those unnatural conditions. We demonstrate here that this inward current also flows at physiological K+ and Na+ concentrations. We show that protons exploit ready reversibility of conformational changes associated with extracellular Na+ release from phosphorylated Na+/K+ pumps. Reversal of a subset of these transitions allows an extracellular proton to bind an acidic side chain and to be subsequently released to the cytoplasm. This back-step of phosphorylated Na+/K+ pumps that enables proton import is not required for completion of the 3 Na+/2 K+ transport cycle. However, the back-step occurs readily during Na+/K+ transport when external K+ ion binding and occlusion are delayed, and it occurs more frequently when lowered extracellular pH raises the probability of protonation of the externally accessible carboxylate side chain. The proton route passes through the Na+-selective binding site III and is distinct from the principal pathway traversed by the majority of transported Na+ and K+ ions that passes through binding site II. The inferred occurrence of Na+/K+ exchange and H+ import during the same conformational cycle of a single molecule identifies the Na+/K+ pump as a hybrid transporter. Whether Na+/K+ pump–mediated proton inflow may have any physiological or pathophysiological significance remains to be clarified. PMID
The local effect of octreotide on mechanical pain sensitivity is more sensitive in DA rats than DA.1U rats.

PubMed

Yao, Fan-Rong; Wang, Hui-Sheng; Guo, Yuan; Zhao, Yan

2016-02-01

A recent study by the authors indicated that major histocompatibility complex (MHC) genes are associated with the differences in basal pain sensitivity and in formalin model between Dark-Agouti (DA) and novel congenic DA.1U rats, which have the same genetic background as DA rats except for the u alleles of MHC. The objective of the present study is to investigate whether there is a difference in the pristane-induced arthritis (PIA) model and local analgesic effect of octreotide (OCT) between DA and DA.1U rats. The hindpaw mechanical withdrawal threshold (MWT) and heat withdrawal latency (HWL) were observed. The C unit firings of the tibial nerve evoked by non-noxious and noxious toe movements were recorded by electrophysiological methods in normal and PIA models in DA and DA.1U rats before and after local OCT administration. The expression of somatostatin receptor 2A (SSTR2A) was observed by immunohistochemistry. The results demonstrate that DA rats have a higher mechanical sensitivity than DA.1U rats after PIA. Local OCT administration significantly elevated MWT in DA rats under normal and PIA sate, but not in DA.1U rats. The electrophysiological experiments showed OCT significantly attenuated the firings of C units evoked by non-noxious and noxious stimulation in DA rats more than those in DA.1U rats both in normal and PIA states. In addition, the expression of SSTR2A in the dorsal horn of the spinal cord was significantly higher in DA than in DA.1U rats. All of the findings suggest a higher local analgesic effect of OCT in DA rats than DA.1U rats, which might be associated with the MHC genes. © 2016 John Wiley & Sons Australia, Ltd.
Long range intermolecular interactions between the alkali diatomics Na(2), K(2), and NaK.

PubMed

Zemke, Warren T; Byrd, Jason N; Michels, H Harvey; Montgomery, John A; Stwalley, William C

2010-06-28

Long range interactions between the ground state alkali diatomics Na(2)-Na(2), K(2)-K(2), Na(2)-K(2), and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies. A simple asymptotic model potential E(LR)=E(elec)+E(disp)+E(ind) is shown to accurately represent the intermolecular interactions for these systems at long range.
Effect of NaNO3 concentration on anodic electrochemical behavior on the Sb surface in NaOH solution

NASA Astrophysics Data System (ADS)

He, Yun-long; Xu, Rui-dong; He, Shi-wei; Chen, Han-sen; Li, Kuo; Zhu, Yun; Shen, Qing-feng

2018-03-01

The effect of NaNO3 concentration on the anodic electrochemical behavior of antimony in 4 M NaOH solution was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses. The mechanism of NO 3 - concentration effect on the anodic electrochemical behavior of antimony was proposed, and its availability was confirmed by experimental results. The effect of NaNO3 on the anodic behavior of antimony in NaOH solution can be interpreted as a stepwise formation of different antimony compounds with different NaNO3 concentrations. Metallic antimony is apt to be oxidized into Sb2O3 within the NaNO3 concentration range of 0-0.48 M. NaSbO3 can be found on the antimony surface when the NaNO3 concentration increases gradually. Insoluable NaSbO3 inhibits the anodic oxidation of antimony due to its shielding effect on the mass transport of the reactants and products. Surface morphology and composition were analyzed by X-ray photoelectron spectroscopy (XPS), scanning electronic microscopy (SEM), and electron dispersion spectroscopy (EDS) analyses. Results indicate that the anodic oxidation layer is composed of Sb2O3, NaSbO3, and Sb. The atomic proportion of antimony in the form of NaSbO3 increases with increasing NaNO3 concentration due to the powerful oxidizing property of NaNO3.

Precursor Routes to Complex Ternary Intermetallics: Single-Crystal and Microcrystalline Preparation of Clathrate-I Na8Al8Si38 from NaSi + NaAlSi.

PubMed

Dong, Yongkwan; Chai, Ping; Beekman, Matt; Zeng, Xiaoyu; Tritt, Terry M; Nolas, George S

2015-06-01

Single crystals of the ternary clathrate-I Na8Al8Si38 were synthesized by kinetically controlled thermal decomposition (KCTD), and microcrystalline Na8Al8Si38 was synthesized by spark plasma sintering (SPS) using a NaSi + NaAlSi mixture as the precursor. Na8AlxSi46-x compositions with x ≤ 8 were also synthesized by SPS from precursor mixtures of different ratios. The crystal structure of Na8Al8Si38 was investigated using both Rietveld and single-crystal refinements. Temperature-dependent transport and UV/vis measurements were employed in the characterization of Na8Al8Si38, with diffuse-reflectance measurement indicating an indirect optical gap of 0.64 eV. Our results indicate that, when more than one precursor is used, both SPS and KCTD are effective methods for the synthesis of multinary inorganic phases that are not easily accessible by traditional solid-state synthesis or crystal growth techniques.
On the Stability of NaO2 in Na-O2 Batteries.

PubMed

Liu, Chenjuan; Carboni, Marco; Brant, William R; Pan, Ruijun; Hedman, Jonas; Zhu, Jiefang; Gustafsson, Torbjörn; Younesi, Reza

2018-04-25

Na-O 2 batteries are regarded as promising candidates for energy storage. They have higher energy efficiency, rate capability, and chemical reversibility than Li-O 2 batteries; in addition, sodium is cheaper and more abundant compared to lithium. However, inconsistent observations and instability of discharge products have inhibited the understanding of the working mechanism of this technology. In this work, we have investigated a number of factors that influence the stability of the discharge products. By means of in operando powder X-ray diffraction study, the influence of oxygen, sodium anode, salt, solvent, and carbon cathode were investigated. The Na metal anode and an ether-based solvent are the main factors that lead to the instability and decomposition of NaO 2 in the cell environment. This fundamental insight brings new information on the working mechanism of Na-O 2 batteries.
Physiological and Metabolic Responses Triggered by Omeprazole Improve Tomato Plant Tolerance to NaCl Stress

PubMed Central

Rouphael, Youssef; Raimondi, Giampaolo; Lucini, Luigi; Carillo, Petronia; Kyriacou, Marios C.; Colla, Giuseppe; Cirillo, Valerio; Pannico, Antonio; El-Nakhel, Christophe; De Pascale, Stefania

2018-01-01

Interest in the role of small bioactive molecules (< 500 Da) in plants is on the rise, compelled by plant scientists' attempt to unravel their mode of action implicated in stimulating growth and enhancing tolerance to environmental stressors. The current study aimed at elucidating the morphological, physiological and metabolomic changes occurring in greenhouse tomato (cv. Seny) treated with omeprazole (OMP), a benzimidazole inhibitor of animal proton pumps. The OMP was applied at three rates (0, 10, or 100 μM) as substrate drench for tomato plants grown under nonsaline (control) or saline conditions sustained by nutrient solutions of 1 or 75 mM NaCl, respectively. Increasing NaCl concentration from 1 to 75 mM decreased the tomato shoot dry weight by 49% in the 0 μM OMP treatment, whereas the reduction was not significant at 10 or 100 μM of OMP. Treatment of salinized (75 mM NaCl) tomato plants with 10 and especially 100 μM OMP decreased Na+ and Cl− while it increased Ca2+ concentration in the leaves. However, OMP was not strictly involved in ion homeostasis since the K+ to Na+ ratio did not increase under combined salinity and OMP treatment. OMP increased root dry weight, root morphological characteristics (total length and surface), transpiration, and net photosynthetic rate independently of salinity. Metabolic profiling of leaves through UHPLC liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry facilitated identification of the reprogramming of a wide range of metabolites in response to OMP treatment. Hormonal changes involved an increase in ABA, decrease in auxins and cytokinin, and a tendency for GA down accumulation. Cutin biosynthesis, alteration of membrane lipids and heightened radical scavenging ability related to the accumulation of phenolics and carotenoids were observed. Several other stress-related compounds, such as polyamine conjugates, alkaloids and sesquiterpene lactones, were altered in response to OMP. Although a
Impact of natural climate change and historical land use on vegetation cover and geomorphological process dynamics in the Serra dos Órgãos mountain range in Rio de Janeiro State, Brazil

NASA Astrophysics Data System (ADS)

Nehren, U.; Sattler, D.; Heinrich, J.

2010-03-01

The Serra dos Órgãos mountain range in the hinterland of Rio de Janeiro contains extensive remnants of the Atlantic Forest (Mata Atlântica) biome, which once covered about 1.5 million km² from Northeast to South Brazil and further inland to Paraguay and Argentina. As a result of historical deforestation and recent land use intensification processes today only 5 to 8% of the original Atlantic Forest remains. Despite the dramatic habitat loss and a high degree of forest fragmentation, the remnants are among the Earth’s most diverse habitats in terms of species richness. Furthermore, they are characterized by a high level of endemism. Therefore, the biome is considered a "hotspot of biodiversity". In the last years many efforts have been taken to investigate the Mata Atlântica biome in different spatial and time scales and from different scientific perspectives. We are working in the Atlantic Forest of Rio de Janeiro since 2004 and focus in our research particularly on Quaternary landscape evolution and landscape history. By means of landscape and soil archives we reconstruct changes in the landscape system, which are mainly the result of Quaternary climate variability, young tectonic uplift and human impact. The findings throw light on paleoecological conditions in the Late Quaternary and the impact of pre-colonial and colonial land use practices on these landscapes. In this context, a main focus is set on climate and human-driven changes of the vegetation cover and its consequences for the geomorphological process dynamics, in particular erosion and sedimentation processes. Research methods include geomorphological field studies, interpretation of satellite images, physical and chemical sediment and soil analyses as well as relative and absolute dating (Feo/Fed ratio and 14C dating). For the Late Quaternary landscape evolution, the findings are compared with results from paleoclimatic and paloecological investigations in Southeast and South Brazil using other
Functional Interaction between the Scaffold Protein Kidins220/ARMS and Neuronal Voltage-Gated Na+ Channels.

PubMed

Cesca, Fabrizia; Satapathy, Annyesha; Ferrea, Enrico; Nieus, Thierry; Benfenati, Fabio; Scholz-Starke, Joachim

2015-07-17

Kidins220 (kinase D-interacting substrate of 220 kDa)/ankyrin repeat-rich membrane spanning (ARMS) acts as a signaling platform at the plasma membrane and is implicated in a multitude of neuronal functions, including the control of neuronal activity. Here, we used the Kidins220(-/-) mouse model to study the effects of Kidins220 ablation on neuronal excitability. Multielectrode array recordings showed reduced evoked spiking activity in Kidins220(-/-) hippocampal networks, which was compatible with the increased excitability of GABAergic neurons determined by current-clamp recordings. Spike waveform analysis further indicated an increased sodium conductance in this neuronal subpopulation. Kidins220 association with brain voltage-gated sodium channels was shown by co-immunoprecipitation experiments and Na(+) current recordings in transfected HEK293 cells, which revealed dramatic alterations of kinetics and voltage dependence. Finally, an in silico interneuronal model incorporating the Kidins220-induced Na(+) current alterations reproduced the firing phenotype observed in Kidins220(-/-) neurons. These results identify Kidins220 as a novel modulator of Nav channel activity, broadening our understanding of the molecular mechanisms regulating network excitability. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
75 FR 75868 - Airworthiness Directives; Diamond Aircraft Industries GmbH Models DA 40 and DA 40F Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-07

... Airworthiness Directives; Diamond Aircraft Industries GmbH Models DA 40 and DA 40F Airplanes AGENCY: Federal... of the Thielert Engine Owners Group commented that the Model DA 42 has the same door design and the same unsafe condition. He recommended that the AD also apply to the Model DA 42. The FAA has discussed...
Na+/H+ and Na+/NH4+ exchange activities of zebrafish NHE3b expressed in Xenopus oocytes

PubMed Central

Ito, Yusuke; Kato, Akira; Hirata, Taku; Hirose, Shigehisa

2014-01-01

Zebrafish Na+/H+ exchanger 3b (zNHE3b) is highly expressed in the apical membrane of ionocytes where Na+ is absorbed from ion-poor fresh water against a concentration gradient. Much in vivo data indicated that zNHE3b is involved in Na+ absorption but not leakage. However, zNHE3b-mediated Na+ absorption has not been thermodynamically explained, and zNHE3b activity has not been measured. To address this issue, we overexpressed zNHE3b in Xenopus oocytes and characterized its activity by electrophysiology. Exposure of zNHE3b oocytes to Na+-free media resulted in significant decrease in intracellular pH (pHi) and intracellular Na+ activity (aNai). aNai increased significantly when the cytoplasm was acidified by media containing CO2-HCO3− or butyrate. Activity of zNHE3b was inhibited by amiloride or 5-ethylisopropyl amiloride (EIPA). Although the activity was accompanied by a large hyperpolarization of ∼50 mV, voltage-clamp experiments showed that Na+/H+ exchange activity of zNHE3b is electroneutral. Exposure of zNHE3b oocytes to medium containing NH3/NH4+ resulted in significant decreases in pHi and aNai and significant increase in intracellular NH4+ activity, indicating that zNHE3b mediates the Na+/NH4+ exchange. In low-Na+ (0.5 mM) media, zNHE3b oocytes maintained aNai of 1.3 mM, and Na+-influx was observed when pHi was decreased by media containing CO2-HCO3− or butyrate. These results provide thermodynamic evidence that zNHE3b mediates Na+ absorption from ion-poor fresh water by its Na+/H+ and Na+/NH4+ exchange activities. PMID:24401990
Shoot Na+ exclusion and increased salinity tolerance engineered by cell type-specific alteration of Na+ transport in Arabidopsis.

PubMed

Møller, Inge S; Gilliham, Matthew; Jha, Deepa; Mayo, Gwenda M; Roy, Stuart J; Coates, Juliet C; Haseloff, Jim; Tester, Mark

2009-07-01

Soil salinity affects large areas of cultivated land, causing significant reductions in crop yield globally. The Na+ toxicity of many crop plants is correlated with overaccumulation of Na+ in the shoot. We have previously suggested that the engineering of Na+ exclusion from the shoot could be achieved through an alteration of plasma membrane Na+ transport processes in the root, if these alterations were cell type specific. Here, it is shown that expression of the Na+ transporter HKT1;1 in the mature root stele of Arabidopsis thaliana decreases Na+ accumulation in the shoot by 37 to 64%. The expression of HKT1;1 specifically in the mature root stele is achieved using an enhancer trap expression system for specific and strong overexpression. The effect in the shoot is caused by the increased influx, mediated by HKT1;1, of Na+ into stelar root cells, which is demonstrated in planta and leads to a reduction of root-to-shoot transfer of Na+. Plants with reduced shoot Na+ also have increased salinity tolerance. By contrast, plants constitutively expressing HKT1;1 driven by the cauliflower mosaic virus 35S promoter accumulated high shoot Na+ and grew poorly. Our results demonstrate that the modification of a specific Na+ transport process in specific cell types can reduce shoot Na+ accumulation, an important component of salinity tolerance of many higher plants.
Ecotoxicological evaluation of three deicers (NaCl, NaFo, CMA)-effect on terrestrial organisms.

PubMed

Robidoux, P Y; Delisle, C E

2001-02-01

The use of chemical deicers such as sodium chloride (NaCl) has increased significantly during the past three decades. Deicers induce metal corrosion and alter the physicochemical properties of soils and water. Environmental damage caused by the use of NaCl has prompted government agencies to find alternative deicers. This article presents a comparative ecotoxicological study of three deicers on soil organisms. Sodium formiate (NaFo) and calcium-magnesium acetate (CMA) are the most interesting commercially available deicers based upon their characteristics and potential toxicity. Organisms used in this study were four species of macrophytes (cress (Lepidium sativum), barley (Ordeum vulgare), red fescue grass (Festuca rubra), Kentucky bluegrass (Poa pratensis)) and an invertebrate (Eisenia fetida). Using standardized and modified methods, the relative toxicity of deicers was CMA < NaFo congruent with NaCl. The results demonstrate that these chemicals could have similar impacts in terrestrial environments since similar quantities of NaFo and greater amounts of CMA are necessary to achieve the same efficiency as NaCl. The toxicity of the tested substances was lower in natural composted soil than in artificial substrate (silica or OECD soil), indicating decreased environmental bioavailability. The response of the organisms changed according to endpoint, species, and soil characteristics (artificial substrate as compared to natural organic soil). The most sensitive endpoint measured was macrophyte growth with Kentucky bluegrass being the most sensitive species. Copyright 2001 Academic Press.
Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton

PubMed Central

Kong, Xiangqiang; Luo, Zhen; Dong, Hezhong; Eneji, A. Egrinya

2012-01-01

A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM). In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na+ concentrations in leaves. The [Na+] in the ‘0’ side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the ‘0’ side phloem was girdled, suggesting that the increased [Na+] in the ‘0’ side roots was possibly due to transportation of foliar Na+ to roots through phloem. Plants under non-uniform salinity extruded more Na+ from the root than those under uniform salinity. Root Na+ efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na+ efflux and H+ influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na+ extrusion was probably due to active Na+/H+ antiport across the plasma membrane. Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na+ concentration, transport of excessive foliar Na+ to the low salinity side, and enhanced Na+ efflux from the low salinity root. PMID:22200663
Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles.

PubMed

Peckhaus, Andreas; Kiselev, Alexei; Wagner, Robert; Duft, Denis; Leisner, Thomas

2016-12-28

Recent laboratory studies indicate that the hydrated form of crystalline NaCl is potentially important for atmospheric processes involving depositional ice nucleation on NaCl dihydrate particles under cirrus cloud conditions. However, recent experimental studies reported a strong discrepancy between the temperature intervals where the efflorescence of NaCl dihydrate has been observed. Here we report the measurements of the volume specific nucleation rate of crystalline NaCl in the aqueous solution droplets of pure NaCl suspended in an electrodynamic balance at constant temperature and humidity in the range from 250 K to 241 K. Based on these measurements, we derive the interfacial energy of crystalline NaCl dihydrate in a supersaturated NaCl solution and determined its temperature dependence. Taking into account both temperature and concentration dependence of nucleation rate coefficients, we explain the difference in the observed fractions of NaCl dihydrate reported in the previous studies. Applying the heterogeneous classical nucleation theory model, we have been able to reproduce the 5 K shift of the NaCl dihydrate efflorescence curve observed for the sea salt aerosol particles, assuming the presence of super-micron solid inclusions (hypothetically gypsum or hemihydrate of CaSO 4 ). These results support the notion that the phase transitions in microscopic droplets of supersaturated solution should be interpreted by accounting for the stochastic nature of homogeneous and heterogeneous nucleation and cannot be understood on the ground of bulk phase diagrams alone.
Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles

NASA Astrophysics Data System (ADS)

Peckhaus, Andreas; Kiselev, Alexei; Wagner, Robert; Duft, Denis; Leisner, Thomas

2016-12-01

Recent laboratory studies indicate that the hydrated form of crystalline NaCl is potentially important for atmospheric processes involving depositional ice nucleation on NaCl dihydrate particles under cirrus cloud conditions. However, recent experimental studies reported a strong discrepancy between the temperature intervals where the efflorescence of NaCl dihydrate has been observed. Here we report the measurements of the volume specific nucleation rate of crystalline NaCl in the aqueous solution droplets of pure NaCl suspended in an electrodynamic balance at constant temperature and humidity in the range from 250 K to 241 K. Based on these measurements, we derive the interfacial energy of crystalline NaCl dihydrate in a supersaturated NaCl solution and determined its temperature dependence. Taking into account both temperature and concentration dependence of nucleation rate coefficients, we explain the difference in the observed fractions of NaCl dihydrate reported in the previous studies. Applying the heterogeneous classical nucleation theory model, we have been able to reproduce the 5 K shift of the NaCl dihydrate efflorescence curve observed for the sea salt aerosol particles, assuming the presence of super-micron solid inclusions (hypothetically gypsum or hemihydrate of CaSO4). These results support the notion that the phase transitions in microscopic droplets of supersaturated solution should be interpreted by accounting for the stochastic nature of homogeneous and heterogeneous nucleation and cannot be understood on the ground of bulk phase diagrams alone.
Scintillation efficiency measurement of Na recoils in NaI(Tl) below the DAMA/LIBRA energy threshold

NASA Astrophysics Data System (ADS)

Xu, Jingke; Shields, Emily; Calaprice, Frank; Westerdale, Shawn; Froborg, Francis; Suerfu, Burkhant; Alexander, Thomas; Aprahamian, Ani; Back, Henning O.; Casarella, Clark; Fang, Xiao; Gupta, Yogesh K.; Ianni, Aldo; Lamere, Edward; Lippincott, W. Hugh; Liu, Qian; Lyons, Stephanie; Siegl, Kevin; Smith, Mallory; Tan, Wanpeng; Kolk, Bryant Vande

2015-07-01

The dark matter interpretation of the DAMA modulation signal depends on the NaI(Tl) scintillation efficiency of nuclear recoils. Previous measurements for Na recoils have large discrepancies, especially in the DAMA/LIBRA modulation energy region. We report a quenching effect measurement of Na recoils in NaI(Tl) from 3 to 52 keVnr, covering the whole DAMA/LIBRA energy region for dark matter-Na scattering interpretations. By using a low-energy, pulsed neutron beam, a double time-of-flight technique, and pulse-shape discrimination methods, we obtained the most accurate measurement of this kind for NaI(Tl) to date. The results differ significantly from the DAMA reported values at low energies but fall between the other previous measurements. We present the implications of the new quenching results for the dark matter interpretation of the DAMA modulation signal.
Dynamic polarizabilities and Van der Waals coefficients for alkali atoms Li, Na and alkali dimer molecules Li2, Na2 and NaLi

NASA Astrophysics Data System (ADS)

Mérawa, M.; Dargelos, A.

1998-07-01

The present paper gives an account of investigations of the polarizability of the alkali atoms Li, Na, diatomics homonuclear and heteronuclear Li2, Na2 and NaLi at SCF (Self Consistent Field) level of approximation and at correlated level, using a time Time-Dependent Gauge Invariant method (TDGI). Our static polarizability values agree with the best experimental and theoretical determinations. The Van der Waals C6 coefficients for the atom-atom, atom-dimer and dimer-dimer interactions have been evaluated. Les polarisabilités des atomes alcalins Li, Na, et des molécules diatomiques homonucléaires et hétéronucléaire Li2, Na2 et NaLi, ont été calculées au niveau SCF (Self Consistent Field) et au niveau corrélé à partir d'une méthode invariante de jauge dépendante du temps(TDGI). Nos valeurs des polarisabilités statiques sont en accord avec les meilleurs déterminations expérimentales et théoriques. Les coefficients C6 de Van de Waals pour les interactions atome-atome, atome-dimère et dimère-dimère ont également été évalués.
On Ensino da Astronomia no Ensino Médio sob Diferentes Abordagens Metodológicas

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon; Albrecht, Evonir

2011-12-01

O presente trabalho, sobre a intervenção de metodologias de ensino, foi desenvolvido na Escola Estadual Colônia dos Pescadores, na cidade de Caraguatatuba - SP, em três turmas do terceiro ano do Ensino Médio, perfazendo um total de 119 educandos, entre 16 e 19 anos. Antes de iniciar-se a intervenção, um questionário de vinte perguntas objetivas e dissertativas foi desenvolvido, aplicado pelo professor da classe, que ministrou as aulas correspondentes. Este questionário foi o mesmo em todas as três classes com o objetivo de diagnosticar o conhecimento prévio dos alunos sobre Astronomia. Começando a intervenção nas turmas, o professor envolvido usou três diferentes metodologias de ensino: (A) em forma de seminários, elaborados e apresentados pelos alunos, nos quais o professor fazia apenas as intervenções necessárias, (B) na forma tradicional, com a ajuda de multimídia para o desenvolvimento das aulas e a terceira (C) a tradicional, fazendo uso exclusivo de lousa e giz. No final do trabalho os alunos responderam o mesmo questionário novamente, de modo que os três métodos utilizados puderam ser comparados. Os resultados apresentados após a intervenção foram melhores que os resultados iniciais indicando a ocorrência de uma aprendizagem significativa. Quando os estudantes foram inicialmente questionados sobre quantos planetas existem no nosso sistema solar, a classe A obteve 39% de respostas certas, a classe B 48% e a classe C 46%, mas após o desenvolvimento das atividades, as classes obtiveram respectivamente 94%, 97 % e 90% de aproveitamento. No término do bimestre, foi sugerido aos educandos que elaborassem uma história em quadrinhos, a qual serviu para averiguar se os conceitos inicialmente observados foram alterados e se novos foram agregados. A análise das histórias foi dividida em três partes: Criatividade; Temas abordados; Emprego correto dos conceitos estudados. Ao final quatorze histórias foram confeccionadas. O aprendizado
Studies of Inelastic Collisions of NaK and NaCs Molecules with Atomic Perturbers

NASA Astrophysics Data System (ADS)

Jones, Joshua A.

We have investigated collisions of NaK molecules in the first excited state [2(A)1Sigma+], with Ar and He collision partners using laser-induced fluorescence spectroscopy (LIF) and polarization-labeling (PL) spectroscopy in a two-step excitation scheme. Additionally, we have investigated collisions of NaCs molecules in the first excited state [2(A)1Sigma +] with Ar and He perturbers using the LIF technique. We use a pump-probe, two-step excitation process. The pump laser prepares the molecule in a particular ro-vibrational (v, J) level in the A state. The probe laser frequency is scanned over transitions to the 31Π in NaK or to the 53Π in NaCs. In addition to observing strong direct lines, we also see weak collisional satellite lines that arise from collisions in the intermediate state that take the molecule from the prepared level (v, J) to level (v, J + Delta J). The ratio of the intensity of the collisional line to the intensity of the direct line in LIF and PL yield information about population and orientation transfer. Our results show a propensity for DeltaJ=even collisions of NaK with Ar and an even stronger propensity for collisions with He. Collisions of NaCs with Ar do not show any such J=even propensity. Preliminary investigations of collisions of NaCs with He seem to indicate a slight J=even propensity. In addition, we observe that rotationally inelastic collisions of excited NaK molecules with potassium atoms destroy almost all of the orientation, while collisions with argon destroy about one third to two thirds and collisions with helium destroy only about zero to one third of the initial orientation.
Uma análise do fenômeno “alternância de línguas” na fala de bilíngues intermodais (Libras e Português)

PubMed Central

de Sousa, Aline Nunes; de Quadros, Ronice Müller

2013-01-01

Um interessante fenômeno lingüístico presente nas interações das pessoas bilíngues é a alternância de línguas. Neste trabalho, estamos investigando a alternância entre a língua portuguesa oral e a língua de sinais brasileira – Libras, numa mesma cadeia enunciativa, com o objetivo de identificar e analisar o uso dessa alternância na fala de uma criança e de um adulto (ambos ouvintes, filhos de pais surdos), interagindo em uma situação de bilinguismo intermodal, com interlocutores surdos e ouvintes. A alternância de línguas, nesse caso, ocorre quando se para de falar em português e se alterna para sinalizar. O presente trabalho se caracteriza como um estudo inicial, com análise qualitativa de dados. Fazem parte do nosso corpus nove sessões de interações em Libras e em português oral, gravadas em vídeo, que fazem parte do Projeto Desenvolvimento Bilíngue Bimodal da UFSC. Os dados revelam que as características da alternância de línguas pelo adulto e pela criança parecem ter semelhanças e diferenças. O sujeito adulto parece ter feito um uso da alternância mais preocupado com o curso da interação. A criança, por sua vez, não parece tê-la usado com propósitos pragmáticos específicos. Quanto à extensão das alternâncias, pode-se perceber que tanto a criança quanto o adulto utilizaram enunciados maiores do que uma única palavra isolada. O papel dos interlocutores parece ter sido decisivo nas interações aqui investigadas – especialmente nas do adulto, já que a criança ainda está em processo de tomada de consciência do papel do interlocutor na interação. PMID:24379831
Scintillation efficiency measurement of Na recoils in NaI(Tl) below the DAMA/LIBRA energy threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jingke; Shields, Emily; Calaprice, Frank

2015-07-01

The dark matter interpretation of the DAMA modulation signal depends on the NaI(Tl) scintillation efficiency of nuclear recoils. Previous measurements for Na recoils have large discrepancies, especially in the DAMA/LIBRA modulation energy region. We report a quenching effect measurement of Na recoils in NaI(Tl) from 3 to 52 keVnr, covering the whole DAMA/LIBRA energy region for dark matter-Na scattering interpretations. By using a low-energy, pulsed neutron beam, a double time-of-flight technique, and pulse-shape discrimination methods, we obtained the most accurate measurement of this kind for NaI(Tl) to date. The results differ significantly from the DAMA reported values at low energies butmore » fall between the other previous measurements. We present the implications of the new quenching results for the dark matter interpretation of the DAMA modulation signal.« less
da Vinci decoded: does da Vinci stereopsis rely on disparity?

PubMed

Tsirlin, Inna; Wilcox, Laurie M; Allison, Robert S

2012-11-01

In conventional stereopsis, the depth between two objects is computed based on the retinal disparity in the position of matching points in the two eyes. When an object is occluded by another object in the scene, so that it is visible only in one eye, its retinal disparity cannot be computed. Nakayama and Shimojo (1990) found that a precept of quantitative depth between the two objects could still be established for such stimuli and proposed that this precept is based on the constraints imposed by occlusion geometry. They named this and other occlusion-based depth phenomena "da Vinci stereopsis." Subsequent research found quantitative depth based on occlusion geometry in several other classes of stimuli grouped under the term da Vinci stereopsis. However, Nakayama and Shimojo's findings were later brought into question by Gillam, Cook, and Blackburn (2003), who suggested that quantitative depth in their stimuli was perceived based on conventional disparity. In order to understand whether da Vinci stereopsis relies on one type of mechanism or whether its function is stimulus dependent we examine the nature and source of depth in the class of stimuli used by Nakayama and Shimojo (1990). We use three different psychophysical and computational methods to show that the most likely source for depth in these stimuli is occlusion geometry. Based on these experiments and previous data we discuss the potential mechanisms responsible for processing depth from monocular features in da Vinci stereopsis.
Effect of 14-kDa and 47-kDa protein molecules of age garlic extract on peritoneal macrophages.

PubMed

Daneshmandi, Saeed; Hajimoradi, Monire; Ahmadabad, Hasan Namdar; Hassan, Zuhair Mohammad; Roudbary, Maryam; Ghazanfari, Tooba

2011-03-01

Garlic (Allium sativum), traditionally being used as a spice worldwide, has different applications and is claimed to possess beneficial effects in several health ailments such as tumor and atherosclerosis. Garlic is also an immunomodulator and its different components are responsible for different properties. The present work aimed to assess the effect of protein fractions of garlic on peritoneal macrophages. 14-kDa and 47-kDa protein fractions of garlic were purified. Mice peritoneal macrophages were lavaged and cultured in a microtiter plate and exposed to different concentrations of garlic proteins. MTT assay was performed to evaluate the viability of macrophage. The amount of nitric oxide (NO) was detected in culture supernatants of macrophages by Griess reagent and furthermore, the cytotoxicity study of culture supernatants was carried out on WEHI-164 fibrosarcoma cell line as tumor necrosis factor-α bioassay. MTT assay results for both 14-kDa and 47-kDa protein fractions of stimulated macrophages were not significant (P > 0.05). Both 14-kDa and 47-kDa fractions significantly suppressed production of NO from macrophages (P = 0.007 and P = 0.003, respectively). Cytotoxicity of macrophages' supernatant on WEHI-164 fibrosarcoma cells was not affected by garlic protein fractions (P = 0.066 for 14-kDa and P = 0.085 for 47-kDa fractions). according to our finding, 14-kDa and 47-kDa fractions of aged garlic extract are able to suppress NO production from macrophages, which can be used as a biological advantage. These molecules had no cytotoxic effect on macrophages and do not increase tumoricidal property of macrophages.

Studies of rotationally inelastic collisions of NaK and NaCs with Ar and He perturbers

NASA Astrophysics Data System (ADS)

Jones, J.; Faust, C.; Richter, K.; Wolfe, C. M.; Ashman, S.; Malenda, R. F.; Weiser, P.; Carlus, S.; Fragale, A.; Hickman, A. P.; Huennekens, J.

2013-05-01

We report studies of rotationally inelastic collisions of Ar and He atoms with the molecules NaK and NaCs prepared in various ro-vibrational levels of the A1Σ+ electronic state. We use laser induced fluorescence (LIF) and polarization labeling (PL) spectroscopy in a pump-probe, two step excitation process. The pump excites the molecule to a ro-vibrational level (v , J) in the A state. The probe laser is scanned over transitions to the 31 Π state in NaK or the 53 Π state in NaCs. In addition to strong direct lines, we observe weak satellite lines that arise from collision-induced transitions of the A state level (v , J) to (v , J + ΔJ) . The ratio of intensities of the satellite line to the direct line in LIF and PL yields information about population and orientation transfer. Preliminary results show a strong propensity for collisions with ΔJ =even for NaK; the propensity is larger for He than for Ar. Collisions of NaCs with He show a similar propensity, but collisions of NaCs with Ar do not. Theoretical calculations are also underway. For He-NaK, we have completed potential surface calculations using GAMESS and coupled channel scattering calculations of rotational energy transfer and transfer of orientation. Work supported by NSF and XSEDE.
Clues to NaCN formation

NASA Astrophysics Data System (ADS)

Quintana-Lacaci, G.; Cernicharo, J.; Velilla Prieto, L.; Agúndez, M.; Castro-Carrizo, A.; Fonfría, J. P.; Massalkhi, S.; Pardo, J. R.

2017-11-01

Context. ALMA is providing us essential information on where certain molecules form. Observing where these molecules emission arises from, the physical conditions of the gas, and how this relates with the presence of other species allows us to understand the formation of many species, and to significantly improve our knowledge of the chemistry that occurs in the space. Aims: We studied the molecular distribution of NaCN around IRC +10216, a molecule detected previously, but whose origin is not clear. High angular resolution maps allow us to model the abundance distribution of this molecule and check suggested formation paths. Methods: We modeled the emission of NaCN assuming local thermal equilibrium (LTE) conditions. These profiles were fitted to azimuthal averaged intensity profiles to obtain an abundance distribution of NaCN. Results: We found that the presence of NaCN seems compatible with the presence of CN, probably as a result of the photodissociation of HCN, in the inner layers of the ejecta of IRC +10216. However, similar as for CH3CN, current photochemical models fail to reproduce this CN reservoir. We also found that the abundance peak of NaCN appears at a radius of 3 × 1015 cm, approximately where the abundance of NaCl, suggested to be the parent species, starts to decay. However, the abundance ratio shows that the NaCl abundance is lower than that obtained for NaCN. We expect that the LTE assumption might result in NaCN abundances higher than the real ones. Updated photochemical models, collisional rates, and reaction rates are essential to determine the possible paths of the NaCN formation. Based on observations carried out with ALMA and the IRAM 30 m Telescope. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. IRAM is supported by INSU/CNRS (France
Study on Na layer response to geomagnetic activities based on Odin/OSIRIS Na density data

NASA Astrophysics Data System (ADS)

Tsuda, Takuo; Nakamura, Takuji; Hedin, Jonas; Gumbel, Jorg; Hosokawa, Keisuke; Ejiri, Mitsumu K.; Nishiyama, Takanori; Takahashi, Toru

2016-07-01

The Na layer is normally distributed from 80 to 110 km, and the height range is corresponding to the ionospheric D and E region. In the polar region, the energetic particles precipitating from the magnetosphere can often penetrate into the E region and even into the D region. Thus, the influence of the energetic particles to the Na layer is one of interests in the aspect of the atmospheric composition change accompanied with the auroral activity. There are several previous studies in this issue. For example, recently, we have reported an initial result on a clear relationship between the electron density increase (due to the energetic particles) and the Na density decrease from observational data sets obtained by Na lidar, EISCAT VHF radar, and optical instruments at Tromsoe, Norway on 24-25 January 2012. However, all of the previous studies had been carried out based on case studies by ground-based lidar observations. In this study, we have performed, for the first time, statistical analysis using Na density data from 2004 to 2009 obtained with the Optical Spectrograph and InfraRed Imager System (OSIRIS) onboard Odin satellite. In the presentation, we will show relationship between the Na density and geomagnetic activities, and its latitudinal variation. Based on these results, the Na layer response to the energetic particles will be discussed.
Multivariate analysis applied to monthly rainfall over Rio de Janeiro state, Brazil

NASA Astrophysics Data System (ADS)

Brito, Thábata T.; Oliveira-Júnior, José F.; Lyra, Gustavo B.; Gois, Givanildo; Zeri, Marcelo

2017-10-01

Spatial and temporal patterns of rainfall were identified over the state of Rio de Janeiro, southeast Brazil. The proximity to the coast and the complex topography create great diversity of rainfall over space and time. The dataset consisted of time series (1967-2013) of monthly rainfall over 100 meteorological stations. Clustering analysis made it possible to divide the stations into six groups (G1, G2, G3, G4, G5 and G6) with similar rainfall spatio-temporal patterns. A linear regression model was applied to a time series and a reference. The reference series was calculated from the average rainfall within a group, using nearby stations with higher correlation (Pearson). Based on t-test ( p < 0.05) all stations had a linear spatiotemporal trend. According to the clustering analysis, the first group (G1) contains stations located over the coastal lowlands and also over the ocean facing area of Serra do Mar (Sea ridge), a 1500 km long mountain range over the coastal Southeastern Brazil. The second group (G2) contains stations over all the state, from Serra da Mantiqueira (Mantiqueira Mountains) and Costa Verde (Green coast), to the south, up to stations in the Northern parts of the state. Group 3 (G3) contains stations in the highlands over the state (Serrana region), while group 4 (G4) has stations over the northern areas and the continent-facing side of Serra do Mar. The last two groups were formed with stations around Paraíba River (G5) and the metropolitan area of the city of Rio de Janeiro (G6). The driest months in all regions were June, July and August, while November, December and January were the rainiest months. Sharp transitions occurred when considering monthly accumulated rainfall: from January to February, and from February to March, likely associated with episodes of "veranicos", i.e., periods of 4-15 days of duration with no rainfall.
Preparation of Al-La Master Alloy by Thermite Reaction in NaF-NaCl-KCl Molten Salt

NASA Astrophysics Data System (ADS)

Jang, Poknam; Li, Hyonmo; Kim, Wenjae; Wang, Zhaowen; Liu, Fengguo

2015-05-01

A NaF-NaCl-KCl ternary system containing La2O3 was investigated for the preparation of Al-La master alloy by the thermite reaction method. The solubility of La2O3 in NaF-NaCl-KCl molten salt was determined by the method of isothermal solution saturation. Inductively coupled plasma-optical emission spectroscopy and x-ray diffraction (XRD) analyses were used to consider the content of La2O3 in molten salt and the supernatant composition of molten salt after dissolution of La2O3, respectively. The results showed that the content of NaF had a positive influence on the solubility of La2O3 in NaF-NaCl-KCl molten salts, and the solubility of La2O3 could reach 8.71 wt.% in molten salts of 50 wt.%NaF-50 wt.% (44 wt.%NaCl + 56 wt.%KCl). The XRD pattern of cooling molten salt indicated the formation of LaOF in molten salt, which was probably obtained by the reaction between NaF and La2O3. The kinetic study showed that the thermite reaction was in accord with a first-order reaction model. The main influence factors on La content in the Al-La master alloy product, including molten salt composition, amount of Al, concentration of La2O3, stirring, reduction time and temperature, were investigated by single-factor experimentation. The content of La in the Al-La master alloy could be reached to 10.1 wt.%.
Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells

PubMed Central

Vereninov, Igor A.; Yurinskaya, Valentina E.; Model, Michael A.; Vereninov, Alexey A.

2016-01-01

Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1–10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential. PMID:27159324
Accordant summit heights, summit levels and the origin of the ``upper denudation level'' in the Serra do Mar (SE-Brazil, São Paulo): A study of hillslope forms and processes

NASA Astrophysics Data System (ADS)

Römer, Wolfgang

2008-08-01

In southern São Paulo the Serra do Mar is characterized by three distinct terrain types: 1) highly dissected areas with closely spaced ridges and accordant summit heights; 2) multiconvex hills; and 3) terrains with highly elevated watershed areas, irregular summit heights, and locally subdued relief. The development of this landscape is considered to be the result of the Cenozoic block-faulting and of the influences that are exerted by the differing lithological and structural setting of block-faulted compartments on weathering and erosion processes. In areas characterized by pronounced accordant summits the close coincidence between hillslope angle and the angle of limiting stability against landsliding points to a close adjustment of hillslope gradients and the mechanical properties of the regolith. The relative height of the hillslopes is functionally related to the spacing of the valleys and the gradient of the hillslopes. In areas with a regular spacing of v-shaped valleys and uniform rocks, this leads to the intersection of valley-side slopes in summits and ridges at a certain elevation. This elevation is determined by the length and steepness of the valley-side slopes. Therefore, the heights of the summits are geometrically constrained and are likely to indicate the upper limit of summit heights or an "upper denudation level" that is adjusted by hillslope processes to the incising streams. Accordant summit heights of this type are poor indicators of formerly more extensive denudation surfaces as it is also likely that they are a result of the long-term adjustment of hillslopes to river incision. The steep mountain flanks of block-faulted compartments on the other hand, comprise regolith-covered hillslopes that are closely adjusted to the maximum stable gradient as well as rock-slopes that are controlled by the rock-mass strength. Their summits are usually not accommodated into uniform summit levels. Highly elevated watershed areas exhibiting a subdued
Jahn–Teller Assisted Na Diffusion for High Performance Na Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xin; Wang, Yan; Wu, Di

2016-08-30

Na energy storage technology is strategically attractive for large scale applications such as grid energy storage. Here, we show in this paper that there is a clear relation between the Jahn$-$Teller activity of a transition metal ion at the end of charge and the mobility of Na in a cathode material. This is particularly important as mobility at the end of charge limits the capacity of current materials. Consequently, by using this classical piece of physics in the battery world, it is possible to create higher capacity Na-cathode materials. Even more exciting is that the ideal element to impart thismore » effect on cathodes is Fe, which is the least expensive of the transition metal oxides and can therefore enable low cost cathode materials.« less
Na+/K+-ATPase α-subunit in swimming crab Portunus trituberculatus: molecular cloning, characterization, and expression under low salinity stress

NASA Astrophysics Data System (ADS)

Han, Xiaolin; Liu, Ping; Gao, Baoquan; Wang, Haofeng; Duan, Yafei; Xu, Wenfei; Chen, Ping

2015-07-01

Na+/K+-ATPases are membrane-associated enzymes responsible for the active transport of Na+ and K+ ions across cell membranes, generating chemical and electrical gradients. These enzymes' α-subunit provides catalytic function, binding and hydrolyzing ATP, and itself becoming phosphorylated during the transport cycle. In this study, Na+/K+-ATPase α-subunit cDNA was cloned from gill tissue of the swimming crab Portunus trituberculatus by reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end methods. Analysis of the nucleotide sequence revealed that the cDNA had a full-length of 3 833 base pairs (bp), with an open reading frame of 3 120 bp, 5' untranslated region (UTR) of 317 bp, and 3' UTR of 396 bp. The sequence encoded a 1 039 amino acid protein with a predicted molecular weight of 115.57 kDa and with estimated pI of 5.21. It was predicted here to possess all expected features of Na+/K+-ATPase members, including eight transmembrane domains, putative ATP-binding site, and phosphorylation site. Comparison of amino acid sequences showed that the P. trituberculatus α-subunit possessed an overall identity of 75%-99% to that of other organisms. Phylogenetic analysis revealed that this α-subunit was in the same category as those of crustaceans. Quantitative real-time RT-PCR analysis indicated that this α-subunit's transcript were most highly expressed in gill and lowest in muscle. RT-PCR analysis also revealed that α-subunit expression in crab gill decreased after 2 and 6 h, but increased after 12, 24, 48, and 72 h. In addition, α-subunit expression in hepatopancreas of crab decreased after 2-72 h. These facts indicated that the crab's Na+/K+-ATPase α-subunit was potentially involved in the observed acute response to low salinity stress.
Controlled phase stability of highly Na-active triclinic structure in nanoscale high-voltage Na2-2xCo1+xP2O7 cathode for Na-ion batteries

NASA Astrophysics Data System (ADS)

Song, Hee Jo; Kim, Jae-Chan; Dar, Mushtaq Ahmad; Kim, Dong-Wan

2018-02-01

With the increasing demand for high energy density in energy-storage systems, a high-voltage cathode is essential in rechargeable Li-ion and Na-ion batteries. The operating voltage of a triclinic-polymorph Na2CoP2O7, also known as the rose form, is above 4.0 V (vs. Na/Na+), which is relatively high compared to that of other cathode materials. Thus, it can be employed as a potential high-voltage cathode material in Na-ion batteries. However, it is difficult to synthesize a pure rose phase because of its low phase stability, thus limiting its use in high-voltage applications. Herein, compositional-engineered, rose-phase Na2-2xCo1+xP2O7/C (x = 0, 0.1 and 0.2) nanopowder are prepared using a wet-chemical method. The Na2-2xCo1+xP2O7/C cathode shows high electrochemical reactivity with Na ions at 4.0 V, delivering high capacity and high energy density.
Electrogenic Na+/Ca2+ Exchange

PubMed Central

Danaceau, Jonathan P.; Lucero, Mary T.

2000-01-01

Olfactory receptor neurons (ORNs) from the squid, Lolliguncula brevis, respond to the odors l-glutamate or dopamine with increases in internal Ca2+ concentrations ([Ca2+]i). To directly asses the effects of increasing [Ca2+]i in perforated-patched squid ORNs, we applied 10 mM caffeine to release Ca2+ from internal stores. We observed an inward current response to caffeine. Monovalent cation replacement of Na+ from the external bath solution completely and selectively inhibited the caffeine-induced response, and ruled out the possibility of a Ca2+-dependent nonselective cation current. The strict dependence on internal Ca2+ and external Na+ indicated that the inward current was due to an electrogenic Na+/Ca2+ exchanger. Block of the caffeine-induced current by an inhibitor of Na+/Ca2+ exchange (50–100 μM 2′,4′-dichlorobenzamil) and reversibility of the exchanger current, further confirmed its presence. We tested whether Na+/Ca2+ exchange contributed to odor responses by applying the aquatic odor l-glutamate in the presence and absence of 2′,4′-dichlorobenzamil. We found that electrogenic Na+/Ca2+ exchange was responsible for ∼26% of the total current associated with glutamate-induced odor responses. Although Na+/Ca2+ exchangers are known to be present in ORNs from numerous species, this is the first work to demonstrate amplifying contributions of the exchanger current to odor transduction. PMID:10828249
Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

PubMed Central

Abdul Razak, Rafiza; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Hardjito, Djwantoro; Yahya, Zarina

2015-01-01

This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced. PMID:26006238
Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program

NASA Technical Reports Server (NTRS)

Yue, A. S.; Allen, F. G.; Yu, J. G.

1976-01-01

Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.
Effects of ACE inhibition and ANG II stimulation on renal Na-Cl cotransporter distribution, phosphorylation, and membrane complex properties

PubMed Central

Lee, Donna H.; Maunsbach, Arvid B.; Riquier-Brison, Anne D.; Nguyen, Mien T. X.; Fenton, Robert A.; Bachmann, Sebastian; Yu, Alan S.

2013-01-01

The renal distal tubule Na-Cl cotransporter (NCC) reabsorbs <10% of the filtered Na+ but is a key control point for blood pressure regulation by angiotensin II (ANG II), angiotensin-converting enzyme inhibitors (ACEI), and thiazide diuretics. This study aimed to determine whether NCC phosphorylation (NCCp) was regulated by acute (20–30 min) treatment with the ACEI captopril (12 μg/min × 20 min) or by a sub-pressor dose of ANG II (20 ng·kg−1·min−1) in Inactin-anesthetized rats. By immuno-EM, NCCp was detected exclusively in or adjacent to apical plama membranes (APM) in controls and after ACEI or ANG II treatment, while NCC total was detected in both APM and subapical cytoplasmic vesicles (SCV) in all conditions. In renal homogenates, neither ACEI nor ANG II treatment altered NCCp abundance, assayed by immunoblot. However, by density gradient fractionation we identified a pool of low-density APM in which NCCp decreased 50% in response to captopril and was restored during ANG II infusion, and another pool of higher-density APM that responded reciprocally, indicative of regulated redistribution between two APM pools. In both pools, NCCp was preferentially localized to Triton-soluble membranes. Blue Native gel electrophoresis established that APM NCCp localized to ∼700 kDa complexes (containing γ-adducin) while unphosphorylated NCC in intracellular membranes primarily localized to ∼400 kDa complexes: there was no evidence for native monomeric or dimeric NCC or NCCp. In summary, this study demonstrates that phosphorylated NCC, localized to multimeric complexes in the APM, redistributes in a regulated manner within the APM in response to ACEI and ANG II. PMID:23114965
DEZ ANOS DE EXPERIÊNCIA DO COMITÊ DE ÉTICA EM PESQUISA DA SECRETARIA DE SAÚDE DO DISTRITO FEDERAL, BRASIL

PubMed Central

Novaes, Maria Rita C. G.; Guilhem, Dirce; Lolas, Fernando

2009-01-01

O objetivo deste artigo é relatar a experiência do Comitê de Ética em Pesquisa da Secretaria de Estado de Saúde do Distrito Federal (CEP/SES/DF) Brasil, durante o período de 10 anos a partir de sua fundação. Trata-se de uma avaliação descritiva e documental, na modalidade estudo de caso, utilizando-se a totalidade de projetos protocolados no CEP/SES/DF (N° 052/08) nesse período. As pendências mais freqüentes dos projetos foram: termo de consentimento livre e esclarecido (30%), folha de rosto (25%), metodologia (20%), curriculum vitae (12%), planilha de orçamento (9%), outros (4%). O relato das atividades do CEP/SES/DF no período de 10 anos revelou, através de sua produtividade, a legitimidade do processo de análise ética dos protocolos visando à proteção dos participantes da pesquisa. PMID:19888441
Light-driven Na + pump from Gillisia limnaea: A high-affinity Na + binding site is formed transiently in the photocycle

DOE PAGES

Balashov, Sergei P.; Imasheva, Eleonora S.; Dioumaev, Andrei K.; ...

2014-11-06

A group of microbial retinal proteins most closely related to the proton pump xanthorhodopsin has a novel sequence motif and a novel function. Instead of, or in addition to, proton transport, they perform light-driven sodium ion transport, as reported for one representative of this group (KR2) from Krokinobacter. In this paper, we examine a similar protein, GLR from Gillisia limnaea, expressed in Escherichia coli, which shares some properties with KR2 but transports only Na +. The absorption spectrum of GLR is insensitive to Na + at concentrations of ≤3 M. However, very low concentrations of Na + cause profound differencesmore » in the decay and rise time of photocycle intermediates, consistent with a switch from a “Na +-independent” to a “Na +-dependent” photocycle (or photocycle branch) at ~60 μM Na +. The rates of photocycle steps in the latter, but not the former, are linearly dependent on Na + concentration. This suggests that a high-affinity Na + binding site is created transiently after photoexcitation, and entry of Na + from the bulk to this site redirects the course of events in the remainder of the cycle. A greater concentration of Na + is needed for switching the reaction path at lower pH. The data suggest therefore competition between H + and Na + to determine the two alternative pathways. The idea that a Na + binding site can be created at the Schiff base counterion is supported by the finding that upon perturbation of this region in the D251E mutant, Na + binds without photoexcitation. Furthermore, binding of Na+ to the mutant shifts the chromophore maximum to the red like that of H +, which occurs in the photocycle of the wild type.« less
RNA adducts with Na 2SeO 4 and Na 2SeO 3 - Stability and structural features

NASA Astrophysics Data System (ADS)

Nafisi, Shohreh; Manouchehri, Firouzeh; Montazeri, Maryam

2011-12-01

Selenium compounds are widely available in dietary supplements and have been extensively studied for their antioxidant and anticancer properties. Low blood Se levels were found to be associated with an increased incidence and mortality from various types of cancers. Although many in vivo and clinical trials have been conducted using these compounds, their biochemical and chemical mechanisms of efficacy are the focus of much current research. This study was designed to examine the interaction of Na 2SeO 4 and Na 2SeO 3 with RNA in aqueous solution at physiological conditions, using a constant RNA concentration (6.25 mM) and various sodium selenate and sodium selenite/polynucleotide (phosphate) ratios of 1/80, 1/40, 1/20, 1/10, 1/5, 1/2 and 1/1. Fourier transform infrared, UV-Visible spectroscopic methods were used to determine the drug binding modes, the binding constants, and the stability of Na 2SeO 4 and Na 2SeO 3-RNA complexes in aqueous solution. Spectroscopic evidence showed that Na 2SeO 4 and Na 2SeO 3 bind to the major and minor grooves of RNA ( via G, A and U bases) with some degree of the Se-phosphate (PO 2) interaction for both compounds with overall binding constants of K(Na 2SeO 4-RNA) = 8.34 × 10 3 and K(Na 2SeO 3-RNA) = 4.57 × 10 3 M -1. The order of selenium salts-biopolymer stability was Na 2SeO 4-RNA > Na 2SeO 3-RNA. RNA aggregations occurred at higher selenium concentrations. No biopolymer conformational changes were observed upon Na 2SeO 4 and Na 2SeO 3 interactions, while RNA remains in the A-family structure.
Presence of Lutzomyia longipalpis (Diptera: Psychodidae) in the Parque Estadual da Serra da Tiririca, State of Rio de Janeiro, Southeastern Brazil.

PubMed

Fuzari, Andressa Alencastre; Delmondes, Aline Ferreira Dos Santos; Barbosa, Vanessa De Araújo; Marra, Francisco de Assis; Brazil, Reginaldo Peçanha

2016-01-01

The sand fly, Lutzomyia longipalpis, is the main vector of Leishmania infantum in the Americas, primarily occurring in areas of apparent anthropomorphic modifications in several regions of Brazil. Sand flies were captured using light traps. Out of all captured species, Lu. longipalpis numbers had increased within the park. We report the occurrence of Lu. longipalpis in an area of Atlantic Forest, possibly representing the first sylvatic population of Lu. longipalpis in an area absent of peridomestic captures, but with the risk of L. infantum transmission in the areas of Niterói and Maricá.
Na Diffusion in Quasi One-Dimensional Ion Conductor NaMn2O4 Observed by μ+SR

NASA Astrophysics Data System (ADS)

Umegaki, Izumi; Nozaki, Hiroshi; Harada, Masashi; Månsson, Martin; Sakurai, Hiroya; Kawasaki, Ikuto; Watanabe, Isao; Sugiyama, Jun

A quasi one-dimensional (1D) compound, NaMn2O4, in which Mn2O4 zigzag chains form a 1D channel along the b-axis and Na ions locate at the center of the channel, is thought to be a good Na ionic conductor. In order to study Na-ion diffusion, we have measured μ+SR spectra using a powder sample in the temperature range between 100 and 500 K. A diffusive behavior was clearly observed above 325 K. Assuming a thermal activate process for jump diffusion of Na-ion between two nearest neighboring sites, a self diffusion coefficient of Na ion (DNa) and its activation energy (Ea) were estimated as DNa = (3.1 ± 0.2) × 10 - 11 cm2/s at 350 K and Ea = 180(9) meV.
High-Performance Na-O2 Batteries Enabled by Oriented NaO2 Nanowires as Discharge Products.

PubMed

Khajehbashi, S Mohammad B; Xu, Lin; Zhang, Guobin; Tan, Shuangshuang; Zhao, Yan; Wang, Lai-Sen; Li, Jiantao; Luo, Wen; Peng, Dong-Liang; Mai, Liqiang

2018-06-13

Na-O 2 batteries are emerging rechargeable batteries due to their high theoretical energy density and abundant resources, but they suffer from sluggish kinetics due to the formation of large-size discharge products with cubic or irregular particle shapes. Here, we report the unique growth of discharge products of NaO 2 nanowires inside Na-O 2 batteries that significantly boosts the performance of Na-O 2 batteries. For this purpose, a high-spin Co 3 O 4 electrocatalyst was synthesized via the high-temperature oxidation of pure cobalt nanoparticles in an external magnetic field. The discharge products of NaO 2 nanowires are 10-20 nm in diameter and ∼10 μm in length, characteristics that provide facile pathways for electron and ion transfer. With these nanowires, Na-O 2 batteries have surpassed 400 cycles with a fixed capacity of 1000 mA h g -1 , an ultra-low over-potential of ∼60 mV during charging, and near-zero over-potential during discharging. This strategy not only provides a unique way to control the morphology of discharge products to achieve high-performance Na-O 2 batteries but also opens up the opportunity to explore growing nanowires in novel conditions.

Spectral discrimination of lithologic facies in the granite of the Pedra Branca Goias using LANDSAT 1 digital imagery

NASA Technical Reports Server (NTRS)

Parada, N. D. J.; Almeido, R., Jr.

1982-01-01

The applicability of LANDSAT MSS imagery for discriminating geobotanical associations observed in zones of cassiterite-rich metasomatic alterations in the granitic body of Serra da Pedra Branca was investigated. Computer compatible tapes of dry and rainy season imagery were analyzed. Image enlargement, corrections, linear contrast stretch, and ratioing of noncorrelated spectral bands were performed using the Image 100 with a grey scale of 256 levels between zero and 255. Only bands 5 and 7 were considered. Band ratioing of noncorrelated channels (5 and 7) of rainy season imagery permits distinction of areas with different vegetation coverage percentage, which corresponds to geobotanial associations in the area studied. The linear contrast stretch of channel 5, especially of the dry season image is very unsatisfactory in this area.
24Mg(p, α) 21Na reaction study for spectroscopy of 21Na

DOE PAGES

Cha, S. M.; Chae, K. Y.; Kim, A.; ...

2015-11-03

The Mg-24(p, alpha)Na-21 reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain the spins and parities of the energy levels in Na-21 for the astrophysically important F-17(alpha, p)Ne-20 reaction rate calculation. 31-MeV proton beams from the 25-MV tandem accelerator and enriched Mg-24 solid targets were used. When recoiling He-4 particles from the Mg-24(p, alpha)Na-21 reaction we used a highly segmented silicon detector array to detect them; it measured the yields of He-4 particles over a range of angles simultaneously. A observed a new level at 6661 ± 5 keVmore » in the present work. The extracted angular distributions for the first four levels of Na-21 and the results from distorted wave Born approximation (DWBA) calculations were compared to verify and extract the angular momentum transfer.« less
Insight to the Thermal Decomposition and Hydrogen Desorption Behaviors of NaNH2-NaBH4 Hydrogen Storage Composite.

PubMed

Pei, Ziwei; Bai, Ying; Wang, Yue; Wu, Feng; Wu, Chuan

2017-09-20

The lightweight compound material NaNH 2 -NaBH 4 is regarded as a promising hydrogen storage composite due to the high hydrogen density. Mechanical ball milling was employed to synthesize the composite NaNH 2 -NaBH 4 (2/1 molar ratio), and the samples were investigated utilizing thermogravimetric-differential thermal analysis-mass spectroscopy (TG-DTA-MS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. The full-spectrum test (range of the ratio of mass to charge: 0-200) shows that the released gaseous species contain H 2 , NH 3 , B 2 H 6 , and N 2 in the heating process from room temperature to 400 °C, and possibly the impurity gas B 6 H 12 also exists. The TG/DTA analyses show that the composite NaNH 2 -NaBH 4 (2/1 molar ratio) is conductive to generate hydrogen so that the dehydrogenation process can be finished before 400 °C. Moreover, the thermal decomposition process from 200 to 400 °C involves two-step dehydrogenation reactions: (1) Na 3 (NH 2 ) 2 BH 4 hydride decomposes into Na 3 BN 2 and H 2 (200-350 °C); (2) remaining Na 3 (NH 2 ) 2 BH 4 reacts with NaBH 4 and Na 3 BN 2 , generating Na, BN, NH 3 , N 2 , and H 2 (350-400 °C). The better mechanism understanding of the thermal decomposition pathway lays a foundation for tailoring the hydrogen storage performance of the composite complex hydrides system.
Sodium channel diversity in the vestibular ganglion: NaV1.5, NaV1.8, and tetrodotoxin-sensitive currents

PubMed Central

2016-01-01

Firing patterns differ between subpopulations of vestibular primary afferent neurons. The role of sodium (NaV) channels in this diversity has not been investigated because NaV currents in rodent vestibular ganglion neurons (VGNs) were reported to be homogeneous, with the voltage dependence and tetrodotoxin (TTX) sensitivity of most neuronal NaV channels. RT-PCR experiments, however, indicated expression of diverse NaV channel subunits in the vestibular ganglion, motivating a closer look. Whole cell recordings from acutely dissociated postnatal VGNs confirmed that nearly all neurons expressed NaV currents that are TTX-sensitive and have activation midpoints between −30 and −40 mV. In addition, however, many VGNs expressed one of two other NaV currents. Some VGNs had a small current with properties consistent with NaV1.5 channels: low TTX sensitivity, sensitivity to divalent cation block, and a relatively negative voltage range, and some VGNs showed NaV1.5-like immunoreactivity. Other VGNs had a current with the properties of NaV1.8 channels: high TTX resistance, slow time course, and a relatively depolarized voltage range. In two NaV1.8 reporter lines, subsets of VGNs were labeled. VGNs with NaV1.8-like TTX-resistant current also differed from other VGNs in the voltage dependence of their TTX-sensitive currents and in the voltage threshold for spiking and action potential shape. Regulated expression of NaV channels in primary afferent neurons is likely to selectively affect firing properties that contribute to the encoding of vestibular stimuli. PMID:26936982
Enhancement of the sulfur capture capacity of limestones by the addition of Na2CO3 and NaCl.

PubMed

Laursen, K; Grace, J R; Lim, C J

2001-11-01

The ability of Na2CO3 and NaCl to enhance the sulfur capture capacity of three limestones was evaluated via fixed-bed calcination and sulfation experiments. The tested limestones represent three different sulfation morphologies: unreacted-core, network, and uniformly sulfated. Treatment with aqueous or powdered Na2CO3 significantly increased the Ca-utilization for two stones which normally sulfate in an unreacted-core pattern (20% to 45%) and network pattern (33% to 49%). The increase was lower for the uniformly sulfated stone (44% to 48%). Na2CO3 treatment increased the number of macropores leading to uniform sulfation of all particles, nearly eliminating the normal strong dependence of utilization on limestone type and particle size. The effect of Na2CO3 is believed to be associated with formation of a eutectic melt which enhances ionic diffusion and accelerates molecular rearrangement of the CaO. Treatment with aqueous NaCl solution caused a decrease in utilization, probably due to formation of large grains and plugging of pores caused by formation of a large amount of eutectic melt. The effect of Na2CO3 is less sensitive than that of NaCl to the amount added and the combustion environment (temperature and gas composition). In addition, Na2CO3 neither promotes corrosion nor forms chlorinated byproducts, which are main concerns associated with NaCl. Thus, Na2CO3 appears to have significant advantages over NaCl for enhancement of limestone sulfur capture capacity in fluidized-bed combustors.
Concentration dependence of Li+/Na+ diffusion in manganese hexacyanoferrates

NASA Astrophysics Data System (ADS)

Takachi, Masamitsu; Fukuzumi, Yuya; Moritomo, Yutaka

2016-06-01

Manganese hexacyanoferrates (Mn-HCFs) with a jungle-gym-type structure are promising cathode materials for Li+/Na+ secondary batteries (LIBs/SIBs). Here, we investigated the diffusion constants D Li/D Na of Li+/Na+ against the Li+/Na+ concentration x Na/x Li and temperature (T) of A 1.32Mn[Fe(CN)6]0.833.6H2O (A = Li and Na). We evaluated the activation energy E\\text{a}\\text{Li}/E\\text{a}\\text{Na} of D Li/D Na against x Na/x Li. We found that E\\text{a}\\text{Na} steeply increases with x Na from 0.41 eV at x Na = 0.69 to 0.7 eV at 1.1. The increase in E\\text{a}\\text{Na} is ascribed to the occupancy effect of the Na+ site. The increase in E\\text{a}\\text{Li} is suppressed, probably because the number of Li+ sites is three times that of Na+ sites.
Carbon dioxide sequestration using NaHSO4 and NaOH: A dissolution and carbonation optimisation study.

PubMed

Sanna, Aimaro; Steel, Luc; Maroto-Valer, M Mercedes

2017-03-15

The use of NaHSO 4 to leach out Mg fromlizardite-rich serpentinite (in form of MgSO 4 ) and the carbonation of CO 2 (captured in form of Na 2 CO 3 using NaOH) to form MgCO 3 and Na 2 SO 4 was investigated. Unlike ammonium sulphate, sodium sulphate can be separated via precipitation during the recycling step avoiding energy intensive evaporation process required in NH 4 -based processes. To determine the effectiveness of the NaHSO 4 /NaOH process when applied to lizardite, the optimisation of the dissolution and carbonation steps were performed using a UK lizardite-rich serpentine. Temperature, solid/liquid ratio, particle size, concentration and molar ratio were evaluated. An optimal dissolution efficiency of 69.6% was achieved over 3 h at 100 °C using 1.4 M sodium bisulphate and 50 g/l serpentine with particle size 75-150 μm. An optimal carbonation efficiency of 95.4% was achieved over 30 min at 90 °C and 1:1 magnesium:sodium carbonate molar ratio using non-synthesised solution. The CO 2 sequestration capacity was 223.6 g carbon dioxide/kg serpentine (66.4% in terms of Mg bonded to hydromagnesite), which is comparable with those obtained using ammonium based processes. Therefore, lizardite-rich serpentinites represent a valuable resource for the NaHSO 4 /NaOH based pH swing mineralisation process. Copyright © 2016 Elsevier Ltd. All rights reserved.
Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

PubMed

Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

2016-02-01

The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading. Copyright © 2015 Elsevier B.V. All rights reserved.
Adsorption and Formation of Small Na Clusters on Pristine and Double-Vacancy Graphene for Anodes of Na-Ion Batteries.

PubMed

Liang, Zhicong; Fan, Xiaofeng; Zheng, Weitao; Singh, David J

2017-05-24

Layered carbon is a likely anode material for Na-ion batteries (NIBs). Graphitic carbon has a low capacity of approximately 35 (mA h)/g due to the formation of NaC 64 . Using first-principles methods including van der Waals interactions, we analyze the adsorption of Na ions and clusters on graphene in the context of anodes. The interaction between Na ions and graphene is found to be weak. Small Na clusters are not stable on the surface of pristine graphene in the electrochemical environment of NIBs. However, we find that Na ions and clusters can be stored effectively on defected graphene that has double vacancies. In addition, the adsorption energy of small Na clusters near a double vacancy is found to decrease with increasing cluster size. With high concentrations of vacancies the capacity of Na on defective graphene is found to be as much as 10-30 times higher than that of graphitic carbon.
Shoot Na+ Exclusion and Increased Salinity Tolerance Engineered by Cell Type–Specific Alteration of Na+ Transport in Arabidopsis[W][OA

PubMed Central

Møller, Inge S.; Gilliham, Matthew; Jha, Deepa; Mayo, Gwenda M.; Roy, Stuart J.; Coates, Juliet C.; Haseloff, Jim; Tester, Mark

2009-01-01

Soil salinity affects large areas of cultivated land, causing significant reductions in crop yield globally. The Na+ toxicity of many crop plants is correlated with overaccumulation of Na+ in the shoot. We have previously suggested that the engineering of Na+ exclusion from the shoot could be achieved through an alteration of plasma membrane Na+ transport processes in the root, if these alterations were cell type specific. Here, it is shown that expression of the Na+ transporter HKT1;1 in the mature root stele of Arabidopsis thaliana decreases Na+ accumulation in the shoot by 37 to 64%. The expression of HKT1;1 specifically in the mature root stele is achieved using an enhancer trap expression system for specific and strong overexpression. The effect in the shoot is caused by the increased influx, mediated by HKT1;1, of Na+ into stelar root cells, which is demonstrated in planta and leads to a reduction of root-to-shoot transfer of Na+. Plants with reduced shoot Na+ also have increased salinity tolerance. By contrast, plants constitutively expressing HKT1;1 driven by the cauliflower mosaic virus 35S promoter accumulated high shoot Na+ and grew poorly. Our results demonstrate that the modification of a specific Na+ transport process in specific cell types can reduce shoot Na+ accumulation, an important component of salinity tolerance of many higher plants. PMID:19584143
NMR studies on Na+ transport in Synechococcus PCC 6311

NASA Technical Reports Server (NTRS)

Nitschmann, W. H.; Packer, L.

1992-01-01

The freshwater cyanobacterium Synechococcus PCC 6311 is able to adapt to grow after sudden exposure to salt (NaCl) stress. We have investigated the mechanism of Na+ transport in these cells during adaptation to high salinity. Na+ influx under dark aerobic conditions occurred independently of delta pH or delta psi across the cytoplasmic membrane, ATPase activity, and respiratory electron transport. These findings are consistent with the existence of Na+/monovalent anion cotransport or simultaneous Na+/H+ +anion/OH- exchange. Na+ influx was dependent on Cl-, Br-, NO3-, or NO2-. No Na+ uptake occurred after addition of NaI, NaHCO3, or Na2SO4. Na+ extrusion was absolutely dependent on delta pH and on an ATPase activity and/or on respiratory electron transport. This indicates that Na+ extrusion via Na+/H+ exchange is driven by primary H+ pumps in the cytoplasmic membrane. Cells grown for 4 days in 0.5 m NaCl medium, "salt-grown cells," differ from control cells by a lower maximum velocity of Na+ influx and by lower steady-state ratios of [Na+]in/[Na+]out. These results indicate that cells grown in high-salt medium increase their capacity to extrude Na+. During salt adaptation Na+ extrusion driven by respiratory electron transport increased from about 15 to 50%.
Interaction of NaOH solutions with silica surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rimsza, Jessica M.; Jones, Reese E.; Criscenti, Louise J.

Sodium adsorption on silica surfaces depends on the solution counter-ion. Here, we use NaOH solutions to investigate basic environments. Sodium adsorption on hydroxylated silica surfaces from NaOH solutions were investigated through molecular dynamics with a dissociative force field, allowing for the development of secondary molecular species. Furthermore, across the NaOH concentrations (0.01 M – 1.0 M), ~50% of the Na + ions were concentrated in the surface region, developing silica surface charges between –0.01 C/m 2 (0.01 M NaOH) and –0.76 C/m 2 (1.0 M NaOH) due to surface site deprotonation. Five inner-sphere adsorption complexes were identified, including monodentate, bidentate,more » and tridentate configurations and two additional structures, with Na + ions coordinated by bridging oxygen and hydroxyl groups or water molecules. Coordination of Na + ions by bridging oxygen atoms indicates partial or complete incorporation of Na + ions into the silica surface. Residence time analysis identified that Na + ions coordinated by bridging oxygen atoms stayed adsorbed onto the surface four times longer than the mono/bi/tridentate species, indicating formation of relatively stable and persistent Na + ion adsorption structures. Such inner-sphere complexes form only at NaOH concentrations of > 0.5 M. Na + adsorption and lifetimes have implications for the stability of silica surfaces.« less
Interaction of NaOH solutions with silica surfaces

DOE PAGES

Rimsza, Jessica M.; Jones, Reese E.; Criscenti, Louise J.

2018-01-16

Sodium adsorption on silica surfaces depends on the solution counter-ion. Here, we use NaOH solutions to investigate basic environments. Sodium adsorption on hydroxylated silica surfaces from NaOH solutions were investigated through molecular dynamics with a dissociative force field, allowing for the development of secondary molecular species. Furthermore, across the NaOH concentrations (0.01 M – 1.0 M), ~50% of the Na + ions were concentrated in the surface region, developing silica surface charges between –0.01 C/m 2 (0.01 M NaOH) and –0.76 C/m 2 (1.0 M NaOH) due to surface site deprotonation. Five inner-sphere adsorption complexes were identified, including monodentate, bidentate,more » and tridentate configurations and two additional structures, with Na + ions coordinated by bridging oxygen and hydroxyl groups or water molecules. Coordination of Na + ions by bridging oxygen atoms indicates partial or complete incorporation of Na + ions into the silica surface. Residence time analysis identified that Na + ions coordinated by bridging oxygen atoms stayed adsorbed onto the surface four times longer than the mono/bi/tridentate species, indicating formation of relatively stable and persistent Na + ion adsorption structures. Such inner-sphere complexes form only at NaOH concentrations of > 0.5 M. Na + adsorption and lifetimes have implications for the stability of silica surfaces.« less
The da Vinci robot.

PubMed

Moran, Michael E

2006-12-01

One might assume from the title of this paper that the nuances of a complex mechanical robot will be discussed, and this would be correct. On the other hand, the date of the design and possible construction of this robot was 1495, a little more than five centuries ago. The key point in the title is the lack of a trademarked name, as Leonardo was the designer of this sophisticated system. His notes from the Codex Altanticus represent the foundation of this report. English translations of da Vinci's notebooks are currently available. Beginning in the 1950s, investigators at the University of California began to ponder the significance of some of da Vinci's markings on what appeared to be technical drawings. Such markings also occur in his Codex Atlanticus (the largest single collection of da Vinci's sheets, consisting of 1119 separate pages and 481 folios) along with a large number of other mechanical devices. Continuing research at the Instituto e Museo di Storia della Scienza in Florence has yielded a great deal of information about Leonardo's intentions with regard to his mechanical knight. It is now known that da Vinci's robot would have had the outer appearance of a Germanic knight. It had a complex core of mechanical devices that probably was human powered. The robot had two independent operating systems. The first had three degree-of-freedom legs, ankles, knees, and hips. The second had four degrees of freedom in the arms with articulated shoulders, elbows, wrists, and hands. A mechanical analog-programmable controller within the chest provided the power and control for the arms. The legs were powered by an external crank arrangement driving the cable, which connected to key locations near each lower extremity's joints. Da Vinci also is known to have devised a programmable front-wheel-drive automobile with rack-and-pinion suspension mechanisms at age 26. He would recall this device again, when, at age 40, he is thought to have built a programmable automated
Accessing naïve human pluripotency

PubMed Central

De Los Angeles, Alejandro; Loh, Yuin-Han; Tesar, Paul J; Daley, George Q

2014-01-01

Pluripotency manifests during mammalian development through formation of the epiblast, founder tissue of the embryo proper. Rodent pluripotent stem cells can be considered as two distinct states: naïve and primed. Naïve pluripotent stem cell lines are distinguished from primed cells by self-renewal in response to LIF signaling and MEK/GSK3 inhibition (LIF/2i conditions) and two active X chromosomes in female cells. In rodent cells, the naïve pluripotent state may be accessed through at least three routes: explantation of the inner cell mass, somatic cell reprogramming by ectopic Oct4, Sox2, Klf4, and C-myc, and direct reversion of primed post-implantation-associated epiblast stem cells (EpiSCs). In contrast to their rodent counterparts, human embryonic stem cells and induced pluripotent stem cells more closely resemble rodent primed EpiSCs. A critical question is whether naïve human pluripotent stem cells with bona fide features of both a pluripotent state and naïve-specific features can be obtained. In this review, we outline current understanding of the differences between these pluripotent states in mice, new perspectives on the origins of naïve pluripotency in rodents, and recent attempts to apply the rodent paradigm to capture naïve pluripotency in human cells. Unraveling how to stably induce naïve pluripotency in human cells will influence the full realization of human pluripotent stem cell biology and medicine. PMID:22463982
Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yahia, H. Ben; Essehli, R., E-mail: ressehli@qf.org.qa; Avdeev, M.

The new compounds NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} crystallize with a stuffed α-CrPO{sub 4}-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structuresmore » of NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} a statistical disorder Ni{sup 2+}/Cr{sup 3+} was observed on both the 8g and 4a atomic positions, whereas in NaCoCr{sub 2}(PO{sub 4}){sub 3} the statistical disorder Co{sup 2+}/Cr{sup 3+} was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} delivered specific capacities of 352, 385, and 368 mA h g{sup −1}, respectively, which attests to the electrochemical activity of sodium in these compounds. - Highlights: • NaCoCr{sub 2}(PO{sub 4}){sub 3}, NaNiCr{sub 2}(PO{sub 4}){sub 3}, and Na{sub 2}Ni{sub 2}Cr(PO{sub 4}){sub 3} were synthesized by sol-gel method. • The crystal structures were determined by using neutron powder diffraction data. • The three compounds crystallize with a stuffed α-CrPO{sub 4}-type structure. • The three compounds were tested as anodes in sodium-ion batteries. • Relatively high specific capacities were obtained for these compounds.« less
Transcriptional regulators of Na,K-ATPase subunits

PubMed Central

Li, Zhiqin; Langhans, Sigrid A.

2015-01-01

The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease. PMID:26579519
Sepsis does not alter red blood cell glucose metabolism or Na+ concentration: A 2H-, 23Na-NMR study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hotchkiss, R.S.; Song, S.K.; Ling, C.S.

The effects of sepsis on intracellular Na+ concentration ((Na+)i) and glucose metabolism were examined in rat red blood cells (RBCs) by using 23Na- and 2H-nuclear magnetic resonance (NMR) spectroscopy. Sepsis was induced in 15 halothane-anesthetized female Sprague-Dawley rats by using the cecal ligation and perforation technique; 14 control rats underwent cecal manipulation without ligation. The animals were fasted for 36 h, but allowed free access to water. At 36 h postsurgery, RBCs were examined by 23Na-NMR by using dysprosium tripolyphosphate as a chemical shift reagent. Human RBCs from 17 critically ill nonseptic patients and from 7 patients who were diagnosedmore » as septic were also examined for (Na+)i. Five rat RBC specimens had (Na+)i determined by both 23Na-NMR and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). For glucose metabolism studies, RBCs from septic and control rats were suspended in modified Krebs-Henseleit buffer containing (6,6-2H2)glucose and examined by 2H-NMR. No significant differences in (Na+)i or glucose utilization were found in RBCs from control or septic rats. There were no differences in (Na+)i in the two groups of patients. The (Na+)i determined by NMR spectroscopy agreed closely with measurements using ICP-AES and establish that 100% of the (Na+)i of the RBC is visible by NMR. Glucose measurements determined by 2H-NMR correlated closely (correlation coefficient = 0.93) with enzymatic analysis. These studies showed no evidence that sepsis disturbed RBC membrane function or metabolism.« less
Abundâncias de oxigênio e enxofre nas estrelas de tipo solar da vizinhança solar

NASA Astrophysics Data System (ADS)

Requeijo, F.; Porto de Mello, G. F.

2003-08-01

Alguns resultados sugerem que o Sol seja 58% mais abundante em oxigênio que o meio interestelar local. Esta anomalia parece estender-se para o carbono e o criptônio. Entre as possíveis explicações deste fenômeno estão: uma supernova de tipo II que tenha enriquecido a nebulosa protosolar, tornando-a superabundante em oxigênio; um episódio de infall de material pobre em metais sobre o disco Galático, diluindo o meio interestelar local ou uma migração dinâmica do Sol de uma órbita mais interna da Galáxia para sua posição atual. A escolha entre estes cenários exige o conhecimento preciso da abundância solar em relação às anãs G da vizinhança. Neste contexto, o oxigênio e enxofre, são elementos-chave por serem ambos produzidos pelas supernovas de tipo II, devendo portanto possuir o mesmo padrão de abundância. Este projeto visa esclarecer qual a posição do Sol na distribuição local de abundâncias de enxofre e oxigênio para uma amostra de estrelas de tipo solar com idades e metalicidades bem conhecidas. Para tal, analisamos espectros de alta resolução e alta relação sinal-ruído nas regiões espectrais de ll 6300, 7774 (O) e l8695 (S). Para o enxofre encontramos que o Sol parece ser uma estrela típica dentre as da vizinhança, e que este elemento não mostra a sobreabundância para baixas metalicidades, já bem estabelecida para o oxigênio. Discutimos as abundâncias do enxofre no contexto da Evolução Química da Galáxia. Apresentamos resultados preliminares muito precisos para a linha proibida do oxigênio l6300 e comparamos estes com os obtidos para o tripleto em l7774. Quantificamos os efeitos não-ETL presentes no tripleto em função dos parâmetros atmosféricos estelares.
PKC phosphorylates residues in the N-terminal of the DA transporter to regulate amphetamine-induced DA efflux.

PubMed

Wang, Qiang; Bubula, Nancy; Brown, Jason; Wang, Yunliang; Kondev, Veronika; Vezina, Paul

2016-05-27

The DA transporter (DAT), a phosphoprotein, controls extracellular dopamine (DA) levels in the central nervous system through transport or reverse transport (efflux). Multiple lines of evidence support the claim that PKC significantly contributes to amphetamine-induced DA efflux. Other signaling pathways, involving CaMKII and ERK, have also been shown to regulate DAT mediated efflux. Here we assessed the contribution of putative PKC residues (S4, S7, S13) in the N-terminal of the DAT to amphetamine-induced DA efflux by transfecting DATs containing different serine to alanine (S-A) point mutations into DA pre-loaded HEK-293 cells and incubating these cells in amphetamine (2μM). The effects of a S-A mutation at the non-PKC residue S12 and a threonine to alanine (T-A) mutation at the ERK T53 residue were also assessed for comparison. WT-DATs were used as controls. In an initial experiment, we confirmed that inhibiting PKC with Go6976 (130nM) significantly reduced amphetamine-induced DA efflux. In subsequent experiments, cells transfected with the S4A, S12A, S13A, T53A and S4,7,13A mutants showed a reduction in amphetamine-induced DA efflux similar to that observed with Go6976. Interestingly, cells transfected with the S7A mutant, identified by some as a PKC-PKA residue, showed unperturbed WT-DAT levels of amphetamine-induced DA efflux. These results indicate that phosphorylation by PKC of select residues in the DAT N-terminal can regulate amphetamine-induced efflux. PKC can act either independently or in concert with other kinases such as ERK to produce this effect. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[Effect of NaHCO3 stress on uptake and transportation of Na+, K+ and Ca2+ in three shrub species].

PubMed

Mao, Gui-Lian; Li, Guo-Qi; Xu, Xing; Zhang, Xin-Xue

2014-03-01

We detected absorption and transportation of ions in the leaves of Atriplex nummularia, Atriplex canescens and Lycium barbarum under NaHCO3 stress (300 mmol x L(-1)) by using atomic absorption spectrophotometry and non-invasive ion flux measurement. The results showed that leaves of the A. nummularia, A. canescens and L. barbarum exhibited a high capacity to induce the Na+ accumulation when compared with that of control. The higher the concentration of NaHCO3 treatment, the more Na+ accumulated in the leaves of the three plants under experimental condition. L. barbarum showed a higher Na+ efflux in the mesophyll cells, whereas A. nummularia and A. canescens showed a relative lower efflux. A lower K+ content and a higher Na+/K+ ratio were detected in leaves of A. nummularia and L. barbarum. However, a higher K+ content and a lower Na+/K+ ratio were seen in leaves of A. canescens. Due to induction of Ca2+ efflux under the NaHCO3 treatment, a lower Ca2+ content and a higher Na+/Ca2+ ratio were observed in L. barbarum. On the contrary, a higher Ca2+ influx was observed in A. nummularia and A. canescens. These results suggested that the three shrubs species had different Na+ segmentation strategies. The accumulation of Na+ inhibited Ca2+ absorption in leaves of L. barbarum, while in the A. nummularia and A. canescens, Ca2+ influx induced [Ca2+]cyt which preserved a less-depolarized PM and then inhibited K efflux. The maintaining of cellular K+/Na+ homeostasis in A. nummularia and A. canescens might be achieved by the induction of [Ca2+]cyt under the NaHCO3 treatment.
High pressure structural stability of the Na-Te system

NASA Astrophysics Data System (ADS)

Wang, Youchun; Tian, Fubo; Li, Da; Duan, Defang; Xie, Hui; Liu, Bingbing; Zhou, Qiang; Cui, Tian

2018-03-01

The ab initio evolutionary algorithm is used to search for all thermodynamically stable Na-Te compounds at extreme pressure. In our calculations, several new structures are discovered at high pressure, namely, Imma Na2Te, Pmmm NaTe, Imma Na8Te2 and P4/mmm NaTe3. Like the known structures of Na2Te (Fm-3m, Pnma and P63/mmc), the Pmmm NaTe, Imma Na8Te2 and P4/mmm NaTe3 structures also show semiconductor properties with band-gap decreases when pressure increased. However, we find that the band-gap of Imma Na2Te structure increases with pressure. We presume that the result may be caused by the increasing of splitting between Te p states and Na s, Na p and Te d states. Furthermore, we think that the strong hybridization between Na p state and Te d state result in the band gap increasing with pressure.
FTIR spectra of the solid solutions (Na0.88K0.12)VO3, (Na0.5K0.5)VO3, and Na(V0.66P0.34)O3

NASA Astrophysics Data System (ADS)

de Waal, D.; Heyns, A. M.

1992-03-01

It is known that three different solid solutions, (Na0.88K0.12)VO3, (Na0.5K0.5)VO3 and Na(V0.66P0.34)O3, form in the (Na,K)(V,P)O3 system. These compounds all have monoclinic crystal structures similar to the pure alkali metal metavanadates containing small cations, e.g. Li+ and Na+ (Space group C2/c). Metavanadates with large cations like K+, Rb+, C+s and NH+4 form orthorhombic crystals, space group Pbcm. All those are structurally related to the silicate pyroxenes. Na(V0.66P0.34)O3 and (Na0.88K0.12)VO3 have the same modified diopside structure as (alpha) - NaVO3 while (Na0.5K0.5)VO3 adopts the true diopside structure. The infrared spectra of the three solid solutions are reported here in comparison with those of (alpha) -NaVO3 and KVO3. The results are also correlated with those obtained in two independent high pressure Raman studies of NH4VO3 and RbVO3 as the introduction of a larger cation like K+ should increase the pressure in the structure.
A computational study of Na behavior on graphene

NASA Astrophysics Data System (ADS)

Malyi, Oleksandr I.; Sopiha, Kostiantyn; Kulish, Vadym V.; Tan, Teck L.; Manzhos, Sergei; Persson, Clas

2015-04-01

We present the first ab initio and molecular dynamics study of Na adsorption and diffusion on ideal graphene that considers Na-Na interaction and dispersion forces. From density functional theory (DFT) calculations using the generalized gradient approximation (GGA), the binding energy (vs. the vacuum reference state) of -0.75 eV is higher than the cohesive energy of Na metal (ENa metal cohesive energy (EcohDFT - D = - 1.21 eV) when dispersion correction is included (DFT-D), with Eb = -1.14 eV. Both DFT and DFT-D predict that the increase of Na concentration on graphene results in formation of Na complexes. This is evidenced by smaller Bader charge on Na atoms of Na dimer, 0.55e (0.48e for DFT) compared to 0.86e (for both DFT and DFT-D) for the single atom adsorption as well as by the formation of a Nasbnd Na bond identified by analysis of the electron density. These results suggest that ideal graphene is not a promising anode material for Na-ion batteries. Analysis of diffusion pathways for a Na dimer shows that the dimer remains stable during the diffusion, and computed migration barriers are significantly lower for the dimer than that for the single atom diffusion. This indicates that Na-Na interaction should be taken into account during the analysis of Na transport on graphene. Finally, we show that the typical defects (vacancy and divacancy) induce significant strengthening of the Nasbnd C interaction. In particular, the largest change to the interaction is computed for vacancy-defected graphene, where the found lowest binding energy (vs. the metal reference state) is about 1.15 eV (1.21 eV for DFT) lower than that for ideal graphene.
Thyroid thermogenesis. Relationships between Na+-dependent respiration and Na+ + K+-adenosine triphosphatase activity in rat skeletal muscle.

PubMed Central

Asano, Y; Liberman, U A; Edelman, I S

1976-01-01

The effect of thyroid status on QO2, QO2 (t) and NaK-ATPase activity was examined in rat skeletal muscle. QO2(t) (i.e. Na+-transport-dependent respiration) was estimated with ouabain or Na+-free media supplemented with K+. In contrast to the effects of ouabain on ion composition, intracellular K+ was maintained at about 125 meq/liter, and intracellular Na+ was almost nil in the Na+-free media. The estimates of QO2(t) were independent of the considerable differences in tissue ion concentrations. The increase in QO2(t) account for 47% of the increase in QO2 in the transition from the hypothyroid to the euthyroid state and 84% of the increase in the transition from the euthyroid to the hyperthyroid state. Surgical thyroidectomy lowered NaK-ATPase activity of the microsomal fraction (expressed per milligram protein) 32%; injections of triodothyronine (T3) increased this activity 75% in initially hypothyroid rats and 26% in initially euthyroid rats. Thyroidectomy was attended by significant falls in serum Ca and Pi concentrations. Administration of T3 resulted in further declines in serum Ca and marked increases in serum Ps concentrations. Similar effects were seen in 131I-treated rats, but the magnitude of the declines in serum Ca were less. The effects of T3 on QO2, QO2(t), and NaK-ATPase activity of skeletal muscle were indistinguishable in the 131I-ablated and surgically thyroidectomized rats. In thyroidectomized or euthyroid rats given repeated doses of T3, QO2(t) and NaA-ATPase activity increased proportionately. In thyroidectomized rats injected with single doses of T3, either 10, 50, or 250 mug/100 g body wt, QO2(t) increased linearly with NaK-ATPase activity. The kinetics of the NaK-ATPase activity was assessed with an ATP-generating system. T3 elicited a significant increase in Vmax with no change in Km for ATP. PMID:130385
Laser-induced chemiluminescence of NaMg

NASA Astrophysics Data System (ADS)

Benard, D. J.; Michels, H. H.

1982-03-01

An unstructured continuum emission around 670 nm was observed when Mg was added to an optically pumped heat pipe containing Na and K vapor, in good agreement with ab initio calculations of the NaMg potential energy curves. The corresponding excitation spectrum showed that the incident radiation was observed by NaK molecules (X → C transitions).
The role of climate and environmental variables in structuring bird assemblages in the Seasonally Dry Tropical Forests (SDTFs).

PubMed

Gonçalves, Gabriela Silva Ribeiro; Cerqueira, Pablo Vieira; Brasil, Leandro Schlemmer; Santos, Marcos Pérsio Dantas

2017-01-01

Understanding the processes that influence species diversity is still a challenge in ecological studies. However, there are two main theories to discuss this topic, the niche theory and the neutral theory. Our objective was to understand the importance of environmental and spatial processes in structuring bird communities within the hydrological seasons in dry forest areas in northeastern Brazil. The study was conducted in two National Parks, the Serra da Capivara and Serra das Confusões National Parks, where 36 areas were sampled in different seasons (dry, dry/rainy transition, rainy, rainy/dry transition), in 2012 and 2013. We found with our results that bird species richness is higher in the rainy season and lower during the dry season, indicating a strong influence of seasonality, a pattern also found for environmental heterogeneity. Richness was explained by local environmental factors, while species composition was explained by environmental and spatial factors. The environmental factors were more important in explaining variations in composition. Climate change predictions have currently pointed out frequent drought events and a rise in global temperature by 2050, which would lead to changes in species behavior and to increasing desertification in some regions, including the Caatinga. In addition, the high deforestation rates and the low level of representativeness of the Caatinga in the conservation units negatively affects bird communities. This scenario has demonstrated how climatic factors affect individuals, and, therefore, should be the starting point for conservation initiatives to be developed in xeric environments.
The role of climate and environmental variables in structuring bird assemblages in the Seasonally Dry Tropical Forests (SDTFs)

PubMed Central

Gonçalves, Gabriela Silva Ribeiro; Cerqueira, Pablo Vieira; Brasil, Leandro Schlemmer; Santos, Marcos Pérsio Dantas

2017-01-01

Understanding the processes that influence species diversity is still a challenge in ecological studies. However, there are two main theories to discuss this topic, the niche theory and the neutral theory. Our objective was to understand the importance of environmental and spatial processes in structuring bird communities within the hydrological seasons in dry forest areas in northeastern Brazil. The study was conducted in two National Parks, the Serra da Capivara and Serra das Confusões National Parks, where 36 areas were sampled in different seasons (dry, dry/rainy transition, rainy, rainy/dry transition), in 2012 and 2013. We found with our results that bird species richness is higher in the rainy season and lower during the dry season, indicating a strong influence of seasonality, a pattern also found for environmental heterogeneity. Richness was explained by local environmental factors, while species composition was explained by environmental and spatial factors. The environmental factors were more important in explaining variations in composition. Climate change predictions have currently pointed out frequent drought events and a rise in global temperature by 2050, which would lead to changes in species behavior and to increasing desertification in some regions, including the Caatinga. In addition, the high deforestation rates and the low level of representativeness of the Caatinga in the conservation units negatively affects bird communities. This scenario has demonstrated how climatic factors affect individuals, and, therefore, should be the starting point for conservation initiatives to be developed in xeric environments. PMID:28441412
Advancement of technology towards developing Na-ion batteries

NASA Astrophysics Data System (ADS)

Jamesh, Mohammed Ibrahim; Prakash, A. S.

2018-02-01

The Na-ion-batteries are considered much attention for the next-generation power-sources due to the high abundance of Na resources that lower the cost and become the alternative for the state of the art Li-ion batteries in future. In this review, the recently reported potential cathode and anode candidates for Na-ion-batteries are identified in-light-of-their high-performance for the development of Na-ion-full-cells. Further, the recent-progress on the Na-ion full-cells including the strategies used to improve the high cycling-performance (stable even up-to 50000 cycles), operating voltage (even ≥ 3.7 V), capacity (>350 mAhg-1 even at 1000 mAg-1 (based-on-mass-of-the-anode)), and energy density (even up-to 400 Whkg-1) are reviewed. In addition, Na-ion-batteries with the electrodes containing reduced graphene oxide, and the recent developments on symmetric Na-ion-batteries are discussed. Further, this paper identifies the promising Na-ion-batteries including the strategies used to assemble full-cell using hard-carbon-anodes, Na3V2(PO4)3 cathodes, and other-electrode-materials. Then, comparison between aqueous and non-aqueous Na-ion-batteries in terms of voltage and energy density has been given. Later, various types of electrolytes used for Na-ion-batteries including aqueous, non-aqueous, ionic-liquids and solid-state electrolytes are discussed. Finally, commercial and technological-developments on Na-ion-batteries are provided. The scientific and engineering knowledge gained on Na-ion-batteries afford conceivable development for practical application in near future.
Negative electrodes for Na-ion batteries.

PubMed

Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

2014-08-07

Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.
Associação entre sintomas, veias varicosas e refluxo na veia safena magna ao eco-Doppler

PubMed Central

Seidel, Amélia Cristina; Campos, Mariana Baldini; Campos, Raquel Baldini; Harada, Dérica Sayuri; Rossi, Robson Marcelo; Cavalari, Pedro; Miranda, Fausto

2017-01-01

Resumo Contexto A doença venosa crônica requer avaliação clínica, quantificação dos efeitos hemodinâmicos e definição da distribuição anatômica para decisão diagnóstica e tratamento. Métodos Estudo prospectivo realizado em 2015 com amostra de 1.384 pacientes (2.669 membros) com idade entre 17 e 85 anos, sendo 1.227 do sexo feminino. Nas respostas do questionário aplicado, os sintomas pesquisados eram dor, cansaço, sensação de peso, queimação, câimbras e formigamento. Para a formação dos grupos, foi considerado o número de membros, distribuídos em relação ao gênero, ao índice de massa corporal e à idade. Após a definição grupos e a realização do eco-Doppler para estudo da veia safena magna (VSM), os pacientes foram distribuídos em três grupos (I: sintomas presentes e varizes ausentes, II: sintomas ausentes e varizes presentes e III: sintomas presentes e varizes presentes). A análise estatística utilizou o teste qui-quadrado ou exato de Fisher para verificar a homogeneidade entre os grupos. Em caso de associação com significância de 5%, foi calculada a razão de chances. Resultados Para ambos os gêneros, foi observada chance de insuficiência da VSM 11,2 vezes maior no grupo III. Por sua vez, os casos de obesidade mórbida ocorreram 9,1 vezes mais no mesmo grupo. Além disso, pacientes na faixa etária entre 30 e 50 anos desse grupo apresentaram chance de insuficiência da VSM 43,1 vezes maior. Conclusões A insuficiência da VSM foi significantemente mais frequente no grupo III, tanto globalmente como considerando apenas os casos de obesidade mórbida e a faixa etária mais elevada. PMID:29930616
Impaired natriuretic response to high-NaCl diet plus aldosterone infusion in mice overexpressing human CD39, an ectonucleotidase (NTPDase1).

PubMed

Zhang, Yue; Robson, Simon C; Morris, Kaiya L; Heiney, Kristina M; Dwyer, Karen M; Kishore, Bellamkonda K; Ecelbarger, Carolyn M

2015-06-15

Extracellular nucleotides acting through P2 receptors facilitate natriuresis. To define how purinergic mechanisms are involved in sodium homeostasis, we used transgenic (TG) mice that globally overexpress human CD39 (hCD39, NTPDase1), an ectonucleotidase that hydrolyzes extracellular ATP/ADP to AMP, resulting in an altered extracellular purine profile. On a high-sodium diet (HSD, 3.5% Na(+)), urine volume and serum sodium were significantly higher in TG mice but sodium excretion was unaltered. Furthermore, TG mice showed an attenuated fall in urine aldosterone with HSD. Western blot analysis revealed significantly lower densities (∼40%) of the β-subunit of the epithelial sodium channel (ENaC) in medulla, and the major band (85-kDa) of γ-ENaC in TG mice cortex. To evaluate aldosterone-independent differences, in a second experiment, aldosterone was clamped by osmotic minipump at 20 μg/day, and mice were fed either an HSD or a low-sodium diet (LSD, 0.03% Na(+)). Here, no differences in urine volume or osmolality, or serum aldosterone were found, but TG mice showed a modest, yet significant impairment in late natriuresis (days 3 and 4). Several major sodium transporters or channel subunits were differentially expressed between the genotypes. HSD caused a downregulation of Na-Cl cotransporter (NCC) in both genotypes; and had higher cortical levels of NCC, Na-K-ATPase (α-1 subunit), and α- and γ-ENaC. The Na-K-2Cl cotransporter (NKCC2) was downregulated by HSD in wild-type mice, but it increased in TG mice. In summary, our data support the concept that extracellular nucleotides facilitate natriuresis; they also reveal an aldosterone-independent downregulation of major renal sodium transporters and channel subunits by purinergic signaling.
32 CFR 516.25 - DA Form 4.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 3 2010-07-01 2010-07-01 true DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC RELATIONS LITIGATION Reporting Legal Proceedings to HQDA § 516.25 DA Form 4. (a) General. The DA Form 4 (See figure C-2...
A geochemical and geophysical approach to derive a conceptual circulation model of CO2-rich mineral waters: A case study of Vilarelho da Raia, northern Portugal

NASA Astrophysics Data System (ADS)

Marques, J. M.; Santos, Monteiro; Graça, R. C.; Castro, R.; Aires-Barros, L.; Mendes Victor, L. A.

2001-11-01

The Vilarelho da Raia-Chaves region, located in northern Portugal adjacent to the Spanish border, is characterized by both hot and cold CO2-rich mineral waters issuing from springs and drilled wells. The present paper updates the conceptual circulation model of the Vilarelho da Raia cold CO2-rich mineral waters. Vilarelho da Raia mineral waters, dominated by Na and HCO3 ions, have formed mainly by interaction with CO2 of deep-seated mantle origin. The δ18O, δ2H and 3H values indicate that these waters are the result of meteoric waters infiltrating into Larouco Mountain, NW of Vilarelho da Raia, circulating at shallow depths in granitic rocks and moving into Vilarelho da Raia area. The conceptual geochemical and geophysical circulation model indicates that the hot and cold CO2-rich mineral waters of Chaves (76 °C) and Vilarelho da Raia (17 °C) should be considered manifestations of similar but not the same geohydrological systems. Résumé. La région de Vilarelho da Raia - Chaves, située au Portugal près de la frontière Espagnole, est caractérisée par des eaux carbogazeuses, chaudes et froides, émergeant à des sources et dans des puits. Ce travail constitue une mise au point du modèle conceptuel de circulation des eaux minérales carbogazeuses froides de Vilarelho da Raia. Les eaux minérales de Vilarelho da Raia, dans lesquelles les ions Na and HCO3 sont dominants, résultent principalement d'interactions avec du CO2 d'origine mantellique. Les δ18O, les δ2H, et les teneurs en 3H indiquent que ces eaux proviennent de l'infiltration d'eaux météoriques dans le Mont Larouco au NW de Vilarelho da Raia, circulant à faible profondeur dans les granites en direction de la région de Vilarelho da Raia. Le modèle de circulation géochimique et géophysique conduit à penser que les eaux minérales carbogazeuses chaudes et froides de Chaves (76 °C) et de Vilarelho da Raia (17 °C) doivent être considérées comme des manifestations de systèmes hydrog
The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat.

PubMed

Byrt, Caitlin Siobhan; Xu, Bo; Krishnan, Mahima; Lightfoot, Damien James; Athman, Asmini; Jacobs, Andrew Keith; Watson-Haigh, Nathan S; Plett, Darren; Munns, Rana; Tester, Mark; Gilliham, Matthew

2014-11-01

Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.
Elastic Coulomb breakup of 34Na

NASA Astrophysics Data System (ADS)

Singh, G.; Shubhchintak, Chatterjee, R.

2016-08-01

Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our
Abundância química de simbióticas na direção do bojo galáctico

NASA Astrophysics Data System (ADS)

Luna, G. J. M.; Costa, R. D. D.

2003-08-01

O estudo da distribuição de metalicidades de gigantes K no Bojo indica um largo intervalo com valores entre 0.1 a 10 vezes o valor solar. As razões elementais Ca/Fe, Si/Fe, Mg/Fe são típicas de estrelas do halo, apontando para um processo rápido de enriquecimento, via estrelas masssivas (SN's tipo II). No entanto, este cenário não combina com os resultados derivados de nebulosas planetárias do bojo tais como os de Ratag et al. (1992, A&A,255,270), Cuisinier et al.(2000, A&A,353, 543), Escudero e Costa (2001, A&A,380, 300),que obtêm abundâncias análogas às do disco. Neste cenário, o estudo de estrelas simbióticas possibilita uma abordagem particularmente apropriada para o problema das abundâncias químicas de estrelas de massa intermediária em estágios avançados da evoluçao estelar. Apresentamos aqui os resultados da determinacão das abundâncias do grupo do CNO numa extensa amostra de simbióticas do bojo. Aliás, com a disponibilidade de espectros no visível determinamos também abundâncias de Ar, Ne, S e He, fundamentais para analisar os processos de enriquecimento químico ocorridos ao longo da evolução estelar, bem como a evolução química do meio interestelar. Com os espectros UV do satelite IUE obtivemos abundâncias de C, necessárias no estudo da evolução dos sistemas. As relaçoes C/N-O/N mostram que o material nebular é produto do vento da componente gigante e não dos eventos de nova que às vezes acontecem nestes sistemas, como foi mostrado por Nussbaumer et al (1988,A&A,198,179). As abundâncias de Ar, S, Ne e O são compativeis com resultados de fontes no disco e bojo, seguindo o gradiente proposto por muitos autores na literatura a partir de diferentes objetos como cefeidas, nebulosas planetárias e anãs G. (CAPES,FAPESP,CNPq)
Resurgent current of voltage-gated Na+ channels

PubMed Central

Lewis, Amanda H; Raman, Indira M

2014-01-01

Resurgent Na+ current results from a distinctive form of Na+ channel gating, originally identified in cerebellar Purkinje neurons. In these neurons, the tetrodotoxin-sensitive voltage-gated Na+ channels responsible for action potential firing have specialized mechanisms that reduce the likelihood that they accumulate in fast inactivated states, thereby shortening refractory periods and permitting rapid, repetitive, and/or burst firing. Under voltage clamp, step depolarizations evoke transient Na+ currents that rapidly activate and quickly decay, and step repolarizations elicit slower channel reopening, or a ‘resurgent’ current. The generation of resurgent current depends on a factor in the Na+ channel complex, probably a subunit such as NaVβ4 (Scn4b), which blocks open Na+ channels at positive voltages, competing with the fast inactivation gate, and unblocks at negative voltages, permitting recovery from an open channel block along with a flow of current. Following its initial discovery, resurgent Na+ current has been found in nearly 20 types of neurons. Emerging research suggests that resurgent current is preferentially increased in a variety of clinical conditions associated with altered cellular excitability. Here we review the biophysical, molecular and structural mechanisms of resurgent current and their relation to the normal functions of excitable cells as well as pathophysiology. PMID:25172941
Painful Na-channelopathies: an expanding universe.

PubMed

Waxman, Stephen G

2013-07-01

The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic. Copyright © 2013 Elsevier Ltd. All rights reserved.
Integrated Control of Na Transport along the Nephron

PubMed Central

Schnermann, Jürgen

2015-01-01

The kidney filters vast quantities of Na at the glomerulus but excretes a very small fraction of this Na in the final urine. Although almost every nephron segment participates in the reabsorption of Na in the normal kidney, the proximal segments (from the glomerulus to the macula densa) and the distal segments (past the macula densa) play different roles. The proximal tubule and the thick ascending limb of the loop of Henle interact with the filtration apparatus to deliver Na to the distal nephron at a rather constant rate. This involves regulation of both filtration and reabsorption through the processes of glomerulotubular balance and tubuloglomerular feedback. The more distal segments, including the distal convoluted tubule (DCT), connecting tubule, and collecting duct, regulate Na reabsorption to match the excretion with dietary intake. The relative amounts of Na reabsorbed in the DCT, which mainly reabsorbs NaCl, and by more downstream segments that exchange Na for K are variable, allowing the simultaneous regulation of both Na and K excretion. PMID:25098598

MAP17 Is a Necessary Activator of Renal Na+/Glucose Cotransporter SGLT2

PubMed Central

Coady, Michael J.; El Tarazi, Abdulah; Santer, René; Bissonnette, Pierre; Sasseville, Louis J.; Calado, Joaquim; Lussier, Yoann; Dumayne, Christopher; Bichet, Daniel G.

2017-01-01

The renal proximal tubule reabsorbs 90% of the filtered glucose load through the Na+-coupled glucose transporter SGLT2, and specific inhibitors of SGLT2 are now available to patients with diabetes to increase urinary glucose excretion. Using expression cloning, we identified an accessory protein, 17 kDa membrane-associated protein (MAP17), that increased SGLT2 activity in RNA-injected Xenopus oocytes by two orders of magnitude. Significant stimulation of SGLT2 activity also occurred in opossum kidney cells cotransfected with SGLT2 and MAP17. Notably, transfection with MAP17 did not change the quantity of SGLT2 protein at the cell surface in either cell type. To confirm the physiologic relevance of the MAP17–SGLT2 interaction, we studied a cohort of 60 individuals with familial renal glucosuria. One patient without any identifiable mutation in the SGLT2 coding gene (SLC5A2) displayed homozygosity for a splicing mutation (c.176+1G>A) in the MAP17 coding gene (PDZK1IP1). In the proximal tubule and in other tissues, MAP17 is known to interact with PDZK1, a scaffolding protein linked to other transporters, including Na+/H+ exchanger 3, and to signaling pathways, such as the A-kinase anchor protein 2/protein kinase A pathway. Thus, these results provide the basis for a more thorough characterization of SGLT2 which would include the possible effects of its inhibition on colocalized renal transporters. PMID:27288013
Electrical resistivity of liquid Na-alkali alloys

NASA Astrophysics Data System (ADS)

Malan, Rajesh C.; Vora, Aditya M.

2018-05-01

The electrical resistivity (ρ) has been investigated for the liquid Na-alkali alloys. An effort is made to extend the applicability of the potential suggested by Fiolhais and co-workers to the liquid range for alkali group. The universal parameters of the potential are used for the entire calculation. Eight different screening functions proposed by Hartree (H), Hubbard and Sham (HS), Vashishtha and Shingwi (VS), Taylor (T), Ichimaru and Utsumi (IU), Farid et al. (F), Sarkar et al. (S) and Nagy (N) are used to study the electrical resistivity (ρ) of liquid Na-alkali alloys with well-known Faber-Ziman theory along with Percus-Yevic hard sphere (PYHS) reference system. The results of electrical resistivity (ρ) are found in qualitative agreement with experimental data for the Na-K and Na-Rb alloys than those for Na-Li and Na-Cs alloys.
The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance.

PubMed

Górecki, Kamil; Hägerhäll, Cecilia; Drakenberg, Torbjörn

2014-01-15

(23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one. Copyright © 2013 Elsevier Inc. All rights reserved.
Beyond Donor-Acceptor (D-A) Approach: Structure-Optoelectronic Properties-Organic Photovoltaic Performance Correlation in New D-A1 -D-A2 Low-Bandgap Conjugated Polymers.

PubMed

Chochos, Christos L; Drakopoulou, Sofia; Katsouras, Athanasios; Squeo, Benedetta M; Sprau, Christian; Colsmann, Alexander; Gregoriou, Vasilis G; Cando, Alex-Palma; Allard, Sybille; Scherf, Ullrich; Gasparini, Nicola; Kazerouni, Negar; Ameri, Tayebeh; Brabec, Christoph J; Avgeropoulos, Apostolos

2017-04-01

Low-bandgap near-infrared polymers are usually synthesized using the common donor-acceptor (D-A) approach. However, recently polymer chemists are introducing more complex chemical concepts for better fine tuning of their optoelectronic properties. Usually these studies are limited to one or two polymer examples in each case study so far, though. In this study, the dependence of optoelectronic and macroscopic (device performance) properties in a series of six new D-A 1 -D-A 2 low bandgap semiconducting polymers is reported for the first time. Correlation between the chemical structure of single-component polymer films and their optoelectronic properties has been achieved in terms of absorption maxima, optical bandgap, ionization potential, and electron affinity. Preliminary organic photovoltaic results based on blends of the D-A 1 -D-A 2 polymers as the electron donor mixed with the fullerene derivative [6,6]-phenyl-C 71 -butyric acid methyl ester demonstrate power conversion efficiencies close to 4% with short-circuit current densities (J sc ) of around 11 mA cm -2 , high fill factors up to 0.70, and high open-circuit voltages (V oc s) of 0.70 V. All the devices are fabricated in an inverted architecture with the photoactive layer processed in air with doctor blade technique, showing the compatibility with roll-to-roll large-scale manufacturing processes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The Ubiquitin Receptor DA1 Interacts with the E3 Ubiquitin Ligase DA2 to Regulate Seed and Organ Size in Arabidopsis[C][W

PubMed Central

Xia, Tian; Li, Na; Dumenil, Jack; Li, Jie; Kamenski, Andrei; Bevan, Michael W.; Gao, Fan; Li, Yunhai

2013-01-01

Seed size in higher plants is determined by the coordinated growth of the embryo, endosperm, and maternal tissue. Several factors that act maternally to regulate seed size have been identified, such as AUXIN RESPONSE FACTOR2, APETALA2, KLUH, and DA1, but the genetic and molecular mechanisms of these factors in seed size control are almost totally unknown. We previously demonstrated that the ubiquitin receptor DA1 acts synergistically with the E3 ubiquitin ligase ENHANCER1 OF DA1 (EOD1)/BIG BROTHER to regulate the final size of seeds in Arabidopsis thaliana. Here, we describe another RING-type protein with E3 ubiquitin ligase activity, encoded by DA2, which regulates seed size by restricting cell proliferation in the maternal integuments of developing seeds. The da2-1 mutant forms large seeds, while overexpression of DA2 decreases seed size of wild-type plants. Overexpression of rice (Oryza sativa) GRAIN WIDTH AND WEIGHT2, a homolog of DA2, restricts seed growth in Arabidopsis. Genetic analyses show that DA2 functions synergistically with DA1 to regulate seed size, but does so independently of EOD1. Further results reveal that DA2 interacts physically with DA1 in vitro and in vivo. Therefore, our findings define the genetic and molecular mechanisms of three ubiquitin-related proteins DA1, DA2, and EOD1 in seed size control and indicate that they are promising targets for crop improvement. PMID:24045020
Phase equilibria in the NaF-CdO-NaPO{sub 3} system at 873 K and crystal structure and physico-chemical characterizations of the new Na{sub 2}CdPO{sub 4}F fluorophosphate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aboussatar, Mohamed; Laboratoire de Physico-Chimie de l’État Solide, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000 Sfax; Mbarek, Aïcha

Isothermal sections of the diagram representing phase relationships in the NaF-CdO-NaPO{sub 3} system have been investigated by solid state reactions and powder X-ray diffraction. This phase diagram investigation confirms the polymorphism of the NaCdPO{sub 4} side component and the structure of the ß high temperature polymorph (orthorhombic, space group Pnma and unit cell parameters a=9.3118(2), b=7.0459(1), c=5.1849(1) Å has been refined. A new fluorophosphate, Na{sub 2}CdPO{sub 4}F, has been discovered and its crystal structure determined and refined from powder X-ray diffraction data. It exhibits a new 3D structure with orthorhombic symmetry, space group Pnma and unit cell parameters a=5.3731(1), b=6.8530(1),more » c=12.2691(2) Å. The structure is closely related to those of the high temperature polymorph of the nacaphite Na{sub 2}CaPO{sub 4}F and the fluorosilicate Ca{sub 2}NaSiO{sub 4}F but differs essentially in the cationic repartition since the structure is fully ordered with one Na site (8d) and one Cd site (4c). Relationships with other Na{sub 2}M{sup II}PO{sub 4}F (M{sup II}=Mg, Ca, Mn, Fe, Co, Ni) have been examined and the crystal-chemical and topographical analysis of these fluorophosphates is briefly reviewed. IR, Raman, optical and {sup 19}F, {sup 23}Na, {sup 31}P MAS NMR characterizations of Na{sub 2}CdPO{sub 4}F have been investigated. - Graphical abstract: The structure of the compound Na{sub 2}CdPO{sub 4}F, discovered during the study of the phase relationships in the NaF-CdO-NaPO{sub 3} system, has been determined and compared with other Na{sub 2}M{sup II}PO{sub 4}F fluorophosphates. - Highlights: • XRD analysis of the isothermal section of the NaF-CdO-NaPO{sub 3} system at 923 K. • Rietveld refinement of the high temperature polymorph β-NaCdPO{sub 4}. • Crystal structure of the new Na{sub 2}CdPO{sub 4}F fluorophosphate determined from powder XRD. • Crystal structure - composition relationships of Na{sub 2}M{sup II}PO{sub 4}F
Phase equilibria in the NaF-CdO-NaPO3 system at 873 K and crystal structure and physico-chemical characterizations of the new Na2CdPO4F fluorophosphate

NASA Astrophysics Data System (ADS)

Aboussatar, Mohamed; Mbarek, Aïcha; Naili, Houcine; El-Ghozzi, Malika; Chadeyron, Geneviève; Avignant, Daniel; Zambon, Daniel

2017-04-01

Isothermal sections of the diagram representing phase relationships in the NaF-CdO-NaPO3 system have been investigated by solid state reactions and powder X-ray diffraction. This phase diagram investigation confirms the polymorphism of the NaCdPO4 side component and the structure of the ß high temperature polymorph (orthorhombic, space group Pnma and unit cell parameters a=9.3118(2), b=7.0459(1), c=5.1849(1) Å has been refined. A new fluorophosphate, Na2CdPO4F, has been discovered and its crystal structure determined and refined from powder X-ray diffraction data. It exhibits a new 3D structure with orthorhombic symmetry, space group Pnma and unit cell parameters a=5.3731(1), b=6.8530(1), c=12.2691(2) Å. The structure is closely related to those of the high temperature polymorph of the nacaphite Na2CaPO4F and the fluorosilicate Ca2NaSiO4F but differs essentially in the cationic repartition since the structure is fully ordered with one Na site (8d) and one Cd site (4c). Relationships with other Na2MIIPO4F (MII=Mg, Ca, Mn, Fe, Co, Ni) have been examined and the crystal-chemical and topographical analysis of these fluorophosphates is briefly reviewed. IR, Raman, optical and 19F, 23Na, 31P MAS NMR characterizations of Na2CdPO4F have been investigated.
Na8Au9.8(4)Ga7.2 and Na17Au5.87(2)Ga46.63: The diversity of pseudo 5-fold symmetries in the Na-Au-Ga system

NASA Astrophysics Data System (ADS)

Smetana, Volodymyr; Corbett, John D.; Miller, Gordon J.

2013-11-01

The Na-rich part (~30% Na) of the Na-Au-Ga system between NaAu2, NaGa4, and Na22Ga39 has been found to contain the ternary phases Na8Au9.8(4)Ga7.2 (I) and Na17Au5.87(2)Ga46.63 (II), according to the results of single crystal X-ray diffraction measurements. I is orthorhombic, Cmcm, a=5.3040(1), b=24.519(5), c=14.573(3) Å, and contains a network of clusters with local 5-fold symmetry along the a-axis. Such clusters are frequent building units in decagonal quasicrystals and their approximants. II is rhombohedral, R3¯m, a=16.325(2), c=35.242(7) Å, and contains building blocks that are structurally identical to the Bergman-type clusters as well as fused icosahedral units known with active metals, triels and late transition elements. II also contains a polycationic network with elements of the clathrate V type structure. Tight-binding electronic structure calculations using linear muffin-tin-orbital (LMTO) methods on idealized models of I and II indicate that both compounds are metallic with evident pseudogaps at the corresponding Fermi levels. The overall Hamilton bond populations are generally dominated by Au-Ga and Au-Au bonds in I and by Ga-Ga bonds in II; moreover, the Na-Au and Na-Ga contributions in I are unexpectedly large, ~20% of the total. A similar involvement of sodium in covalent bonding has also been found in the electron-richer i-Na13Au12Ga15 quasicrystal approximant.
Projeto do sistema anti-ressonante da fiação dos transdutores para o detector Mario Schenberg

NASA Astrophysics Data System (ADS)

Vieira, S. J.., Jr.; Melo, J. L.

2003-08-01

O detector de ondas gravitacionais Mario Schenberg está sendo projetado e construído pelo grupo Gráviton. Sua construção está ocorrendo no Laboratório de Estado Sólido e Baixas Temperaturas (LESBT) da Universidade de São Paulo, na cidade de São Paulo. Esse detector possui uma massa ressonante esférica de cobre-alumínio, com 65 cm de diâmetro, pesando aproximadamente 1150 Kg, suspensa por um sistema de isolamento vibracional, que se encontra em fase de testes preliminares. A real eficácia desse sistema, entretanto, só poderá ser comprovada quando o detector estiver aparelhado com, pelo menos, um transdutor eletromecânico de altíssima sensibilidade acoplado à massa ressonante. Neste momento, não só este sistema de isolamento vibracional será posto em teste, como o do projeto da fiação que transporta os sinais de microondas até os transdutores e destes para a pré-amplificação. Apesar dessa fiação ter sido projetada para não apresentar nenhum contato com a superfície esférica da antena, de maneira a não haver nenhuma transmissão de ruído vibracional do laboratório para esta, deve-se minimizar o ruído microfônico produzido nessa fiação por oscilações mecânicas, uma vez que ela não utiliza nenhum sistema de isolamento vibracional. Com o intuito de resolver este problema, projetamos uma estrutura, formada por pequenos cilindros conectados por barras, a qual não terá nenhuma ressonância mecânica na faixa de freqüências de interesse para detecção (3000 - 3400 Hz). Desta forma, as vibrações nessa faixa não serão amplificadas. O projeto foi feito usando iterativamente, de maneira a otimizar os resultados obtidos, o programa de elementos finitos Msc/Nastran. Através de simulações feitas neste programa, determinamos os parâmetros geométricos ideais a serem utilizados, os quais proporcionam a maior região espectral de interesse livre de ressonâncias.
Effects of NaBF4 + NaF on the Tensile and Impact Properties of Al-Si-Mg-Fe Alloys

NASA Astrophysics Data System (ADS)

Chen, Zongning; Wang, Tongmin; Zhao, Yufei; Zheng, Yuanping; Kang, Huijun

2015-05-01

NaBF4 + NaF were found to play three roles, i.e., Fe-eliminator, grain refiner, and eutectic modifier, in treating A356 alloy with a high Fe content. The joint effects led to significant improvement in both tensile and impact properties of thus treated alloy. The multiple reactions between the NaBF4 + NaF and Al-Si-Mg-Fe system are suggested to form Fe2B, AlB2, and Na in the melt, as per thermodynamic analysis. The three are responsible for Fe removal, grain refinement, and eutectic modification, respectively. When NaBF4 and NaF are mixed in weight ratio of 1:1, an optimum addition rate is in the range between 1.0 and 2.0 wt pct for treating AlSi7Mg0.3Fe0.65 alloy, based on the results of tensile and impact tests. Excessive addition of the salt may deteriorate the mechanical properties of the alloy, basically owing to overmodification of Si and contamination of salt inclusions.
The effect of NaCl/g/ on the Na2SO4-induced hot corrosion of NiAl

NASA Technical Reports Server (NTRS)

Smeggil, J. G.; Bornstein, N. S.; Decrescente, M. A.

1977-01-01

Studies have been performed to examine the effect of NaCl vapor on the Na2SO4-induced hot corrosion of the alumina former NiAl. In the incubation period associated with such hot corrosion, NaCl(g) has been shown to be effective in removing aluminum from below the protective alumina scale and redepositing it as Al2O3 whiskers on the surface of the Na2SO4-coated sample. Similar effects seen in simple oxidation are associated with isothermal rupturing of the protective alumina scale.
Quantitative (23) Na MRI of human knee cartilage using dual-tuned (1) H/(23) Na transceiver array radiofrequency coil at 7 tesla.

PubMed

Moon, Chan Hong; Kim, Jung-Hwan; Zhao, Tiejun; Bae, Kyongtae Ty

2013-11-01

To develop quantitative dual-tuned (DT) (1) H/(23) Na MRI of human knee cartilage in vivo at 7 Tesla (T). A sensitive (23) Na transceiver array RF coil was developed at 7T. B1 fields generated by the transceiver array coil were characterized and corrected in the (23) Na images. Point spread function (PSF) of the (23) Na images was measured, and the signal decrease due to partial-volume-effect was compensated in [(23) Na] quantification of knee cartilage. SNR and [(23) Na] in anterior femoral cartilage were measured from seven healthy subjects. SNR of (23) Na image with the transceiver array coil was higher than that of birdcage coil. SNR in the cartilage at 2-mm isotropic resolution was 26.80 ± 3.69 (n = 7). B1 transmission and reception fields produced by the DT coil at 7T were similar to each other. Effective full-width-half-maximum of (23) Na image was ∼5 mm at 2-mm resolution. Mean [(23) Na] was 288.13 ± 29.50 mM (n = 7) in the anterior femoral cartilage of normal subjects. We developed a new high-sensitivity (23) Na RF coil for knee MRI at 7T. Our (1) H/(23) Na MRI allowed quantitative measurement of [(23) Na] in knee cartilage by measuring PSF and cartilage thickness from (23) Na and (1) H image, respectively. Copyright © 2013 Wiley Periodicals, Inc.
Quantification of Sodium (Na) in Bone with in Vivo Neutron Activation Analysis (IVNAA) and Its Implications on Na Retention Studies

NASA Astrophysics Data System (ADS)

Coyne, Mychaela

The locations of Na storage and its exchange mechanisms in different tissues in the body are not well known. This information is important for understanding the impact of Na intake, absorption, and retention on human health, especially on the risk of developing chronic diseases like hypertension. In order to non-invasively quantify Na in bone, a compact deuterium-deuterium (DD) neutron generator-based IVNAA system was developed for use in Na nutrition studies. This thesis will first discuss the optimization of the system using MCNP to maximize the thermal neutron flux inside the irradiation cave while limiting radiation exposure to the hand and the whole body. With optimized assembly in place, an animal study was conducted to investigate the storage and exchange of Na in the body. The right posterior legs of two live pigs, one on a low Na diet and one on a high Na diet, were irradiated inside the customized assembly and then measured with a 100% high efficiency high purity germanium detector (HPGe). The results show that the difference in concentration between the pigs on high vs low Na diets was distinguishable with the system. Analysis also shows rapid exchange of Na in the leg during the first 2 hour measurements (with an exchange decay time of 1.3 hours) while the exchange was minimal at the second and third 2 hour measurements, taken 7 and 21 hours post irradiation. With these results, we conclude there is a non or low exchangeable compartment (likely to be bone) for Na storage and that the DD neutron generator-based IVNAA is a useful method in Na nutrition studies.
Leonardo da Vinci and the Downburst.

NASA Astrophysics Data System (ADS)

Gedzelman, Stanley David

1990-05-01

Evidence from the drawings, experiments, and writings of Leonardo da Vinci are presented to demonstrate that da Vinci recognized and, possibly, discovered the downburst and understood its associated airflow. Other early references to vortex flows resembling downbursts are mentioned.
Influência da termoablação com baixa e alta densidade de energia na junção safeno-femoral, utilizando laser endovenoso 1470 nm

PubMed Central

de Araujo, Walter Junior Boim; Erzinger, Fabiano Luiz; Caron, Filipe Carlos; Nejm, Carlos Seme; Timi, Jorge Rufino Ribas

2017-01-01

Resumo Contexto Faz-se importante o conhecimento técnico dos ajustes de potência e de densidade de energia linear endovenosa (linear endovenous energy density, LEED) adequados para atingir o objetivo final da termoablação endovenosa (endovenous laser ablation, EVLA). Objetivos Avaliar a influência de diferentes LEEDs em termos de patência e presença de refluxo, bem como determinar a evolução clínica. Métodos Foram incluídas 60 veias safenas magnas (VSM). Os pacientes foram randomizados em dois grupos: EVLA com baixa potência (7 W e LEED de 20-40 J/cm) e com alta potência (15 W e LEED de 80-100 J/cm). O acompanhamento com eco-Doppler e escore de severidade clínica venoso (VCSS) foi realizado nos intervalos de 3-5 dias, 30 dias, 180 dias e 1 ano após o procedimento. Resultados Dezoito pacientes (29 membros) tratados com 7W de potência e 13 pacientes (23 membros) com 15 W completaram o estudo. Não houve diferença significativa considerando idade, tempo de cirurgia e o uso de analgésicos, lateralidade, gênero e presença de comorbidades. O LEED médio foi de 33,54 J/cm no grupo de 7 W e de 88,66 J/cm no de 15 W. Ambos apresentaram melhora no VCSS, redução significativa dos diâmetros da JSF e ausência de diferença significativa quanto ao aumento do comprimento do coto da VSM e de refluxo após o tratamento. Conclusões A utilização de maior densidade de energia mostrou-se mais efetiva em relação à estabilização do comprimento do coto da VSM e do refluxo em 6 meses. Fazem-se necessários estudos com um período de acompanhamento maior para fundamentar essa hipótese. PMID:29930650
Biochemical characterization of a halophilic, alkalithermophilic protease from Alkalibacillus sp. NM-Da2.

PubMed

Abdel-Hamed, Asmaa R; Abo-Elmatty, Dina M; Wiegel, Juergen; Mesbah, Noha M

2016-11-01

An extracellular, halophilic, alkalithermophilic serine protease from the halo-alkaliphilic Alkalibacillus sp. NM-Da2 was purified to homogeneity by ethanol precipitation and anion-exchange chromatography. The purified protease was a monomeric enzyme with an approximate molecular mass of 35 kDa and exhibited maximal activity at 2.7 M NaCl, pH 55 °C 9 and 56 °C. The protease showed great temperature stability, retaining greater than 80 % of initial activity after 2 h incubation at 55 °C. The protease was also extremely pH tolerant, retaining 80 % of initial activity at pH 55 °C 10.5 after 30 min incubation. Protease hydrolyzed complex substrates, displaying activity on yeast extract, tryptone, casein, gelatin and peptone. Protease activity was inhibited at casein concentrations greater than 1.2 mg/mL. The enzyme was stable and active in 40 % (v/v) solutions of isopropanol, ethanol and benzene and was stable in the presence of the polysorbate surfactant Tween 80. Activity was stimulated with the oxidizing agent hydrogen peroxide. Inhibition with phenyl methylsulfonylfluoride indicates it is a serine protease. Synthetic saline wastewater treated with the protease showed 50 % protein removal after 5 h. Being halophilic, alkaliphilic and thermophilic, in addition to being resistant to organic solvents, this protease has potential for various applications in biotechnological and pharmaceutical industries.
Na(+) transport, and the E(1)P-E(2)P conformational transition of the Na(+)/K(+)-ATPase.

PubMed Central

Babes, A; Fendler, K

2000-01-01

We have used admittance analysis together with the black lipid membrane technique to analyze electrogenic reactions within the Na(+) branch of the reaction cycle of the Na(+)/K(+)-ATPase. ATP release by flash photolysis of caged ATP induced changes in the admittance of the compound membrane system that are associated with partial reactions of the Na(+)/K(+)-ATPase. Frequency spectra and the Na(+) dependence of the capacitive signal are consistent with an electrogenic or electroneutral E(1)P <--> E(2)P conformational transition which is rate limiting for a faster electrogenic Na(+) dissociation reaction. We determine the relaxation rate of the rate-limiting reaction and the equilibrium constants for both reactions at pH 6.2-8.5. The relaxation rate has a maximum value at pH 7.4 (approximately 320 s(-1)), which drops to acidic (approximately 190 s(-1)) and basic (approximately 110 s(-1)) pH. The E(1)P <--> E(2)P equilibrium is approximately at a midpoint position at pH 6.2 (equilibrium constant approximately 0.8) but moves more to the E(1)P side at basic pH 8.5 (equilibrium constant approximately 0.4). The Na(+) affinity at the extracellular binding site decreases from approximately 900 mM at pH 6.2 to approximately 200 mM at pH 8.5. The results suggest that during Na(+) transport the free energy supplied by the hydrolysis of ATP is mainly used for the generation of a low-affinity extracellular Na(+) discharge site. Ionic strength and lyotropic anions both decrease the relaxation rate. However, while ionic strength does not change the position of the conformational equilibrium E(1)P <--> E(2)P, lyotropic anions shift it to E(1)P. PMID:11053130
Test Review: TestDaF

ERIC Educational Resources Information Center

Norris, John; Drackert, Anastasia

2018-01-01

The Test of German as a Foreign Language (TestDaF) plays a critical role as a standardized test of German language proficiency. Developed and administered by the Society for Academic Study Preparation and Test Development (g.a.s.t.), TestDaF was launched in 2001 and has experienced persistent annual growth, with more than 44,000 test takers in…
Control of Glucose- and NaCl-Induced Biofilm Formation by rbf in Staphylococcus aureus

PubMed Central

Lim, Yong; Jana, Malabendu; Luong, Thanh T.; Lee, Chia Y.

2004-01-01

Both Staphylococcus aureus and S. epidermidis are capable of forming biofilm on biomaterials. We used Tn917 mutagenesis to identify a gene, rbf, affecting biofilm formation in S. aureus NCTC8325-4. Sequencing revealed that Rbf contained a consensus region signature of the AraC/XylS family of regulators, suggesting that Rbf is a transcriptional regulator. Insertional duplication inactivation of the rbf gene confirmed that the gene was involved in biofilm formation on polystyrene and glass. Phenotypic analysis of the wild type and the mutant suggested that the rbf gene mediates the biofilm formation of S. aureus at the multicellular aggregation stage rather than at initial attachment. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that the mutation resulted in the loss of an ∼190-kDa protein. Biofilm production by the mutant could be restored by complementation with a 2.5-kb DNA fragment containing the rbf gene. The rbf-specific mutation affected the induction of biofilm formation by glucose and a high concentration of NaCl but not by ethanol. The mutation did not affect the transcription of the ica genes previously shown to be required for biofilm formation. Taken together, our results suggest that the rbf gene is involved in the regulation of the multicellular aggregation step of S. aureus biofilm formation in response to glucose and salt and that this regulation may be mediated through the 190-kDa protein. PMID:14729698
Magnetic upconverting fluorescent NaGdF4:Ln3+ and iron-oxide@NaGdF4:Ln3+ nanoparticles

NASA Astrophysics Data System (ADS)

Shrivastava, Navadeep; Rocha, Uéslen; Muraca, Diego; Jacinto, Carlos; Moreno, Sergio; Vargas, J. M.; Sharma, S. K.

2018-05-01

Microwave assisted solvothermal method has been employed to synthesize multifunctional upconverting β-NaGdF4:Ln3+ and magnetic-upconverting Fe3O4/γ-Fe2O3@NaGdF4:Ln3+ (Ln = Yb and Er) nanoparticles. The powder x-ray diffraction data confirms the hexagonal structure of NaGdF4:Ln3+ and high resolution transmission electron microscopy shows the formation of rod shaped NaGdF4:Ln3+ (˜ 20 nm) and ovoid shaped Fe3O4/γ-Fe2O3@NaGdF4:Ln3+ (˜ 15 nm) nanoparticles. The magnetic hysteresis at 300 K for β-NaGdF4:Ln3+ demonstrates paramagnetic features, whereas iron-oxide@β-NaGdF4:Ln3+ exhibits superparamagnetic behavior along with a linear component at large applied field due to paramagnetic NaGdF4 matrix. Both nanoparticle samples provide an excellent green emitting [(2H11/2, 4S3/2)→4I15/2 (˜ 540 nm)] upconversion luminescence emission under excitation at 980 nm. The energy migration between Yb and Er in NaGdF4 matrix has been explored from 300-800 nm. Intensity variation of blue, green and red lines and the observed luminescence quenching due to the presence of Fe3O4/γ-Fe2O3 in the composite has been proposed. These kinds of materials contain magnetic and luminescence characteristics into single nanoparticle open new possibility for bioimaging applications.

Maintaining the NA atmosphere of Mercury

NASA Astrophysics Data System (ADS)

Killen, R. M.; Morgan, T. H.

1993-02-01

The possible sources of the Na atmosphere of Mercury are calculatively studied. The likely structure, composition, and temperature of the planet's upper crust is examined along with the probable flux of Na from depth by grain boundary diffusion and by Knudsen flow. The creation of fresh regolith is considered along with mechanisms for supplying Na from the surface to the exosphere. The implications of the calculations for the probable abundances in the regolith are discussed.
Analysis of the astronomical concepts presented by teachers of some state schools

NASA Astrophysics Data System (ADS)

Gonzaga, E. P.; Voelzke, M. R.

2011-06-01

Many Basic Education's teachers (EB) don't deal concepts related to astronomy and when they do so, they just follow didactic books which contain many conceptual errors. Astronomy is one of the contents taught in the EB and is part of the curriculum proposed by the Education Department of the State of São Paulo. With the intention to minimise some deficiencies, a University Extension Course for teachers of the Diretoria de Ensino Regional (Mauá, Ribeirão Pires and Rio Grande da Serra) was conducted with the following objectives: to raise alternative conceptions, to subsidise teachers by means of lectures, discussions and workshops, and to check the learning after the course. Therefore, sixteen questions were applied before and after the course. The results were quite satisfactory.
Implementação de um algoritmo para a limpeza de mapas da RCFM

NASA Astrophysics Data System (ADS)

Souza, C. L.; Wuensche, C. A.

2003-08-01

A Radiação Cósmica de Fundo em Microondas (RCFM), descoberta por Penzias e Wilson em 1965, é uma das ferramentas mais poderosas para o estudo da cosmologia. Com a descoberta de flutuações de temperatura na RCFM, da ordem de uma parte em 105, pelo COBE (1992), uma nova era teve início. Nos últimos onze anos, diversos instrumentos fizeram novas medidas de alta precisão, refinando os resultados apresentados pelo COBE, culminando com os resultados recentes do satélite WMAP. A análise de dados da RCFM, especialmente no caso de experimentos com pequena cobertura do céu, apresenta uma série de dificuldades devido a emissões de contaminantes externos, tais como a emissão da Galáxia e de fontes pontuais, e de ruídos intrínsecos tanto ao sistema de detecção quanto à estratégia de observação do céu. Uma das soluções típicas para a filtragem de dados brutos de um experimento para medir flutuações de temperatura é aplicar um gabarito (template) e um filtro passa alta ao produzir mapas simplificados (sem considerar matrizes de correlação ou covariância). No caso de experimentos que utilizam detectores HEMT, essa combinação de filtros remove, satisfatoriamente, ruídos do tipo 1/f gerados pela instabilidade no ganho do detector acoplado ao movimento do instrumento, definido pela estratégia de observação. Entretanto, o sinal resultante medido, tanto em simulações quanto em séries temporais reais, sugere que parte do sinal cosmológico pode estar sendo removido junto com o ruído dos detectores. Este trabalho descreve as etapas para a produção de um mapa típico (simulado) e os testes preliminares de um algoritmo para remover ruídos do tipo 1/f introduzidos pela estratégia de observação sem prejudicar a qualidade do sinal cosmológico presente no mapa.
Thermodynamic description of Tc(iv) solubility and carbonate complexation in alkaline NaHCO3-Na2CO3-NaCl systems.

PubMed

Baumann, A; Yalçıntaş, E; Gaona, X; Polly, R; Dardenne, K; Prüßmann, T; Rothe, J; Altmaier, M; Geckeis, H

2018-03-28

The solubility of 99 Tc(iv) was investigated in dilute to concentrated carbonate solutions (0.01 M ≤ C tot ≤ 1.0 M, with C tot = [HCO 3 - ] + [CO 3 2- ]) under systematic variation of ionic strength (I = 0.3-5.0 M NaHCO 3 -Na 2 CO 3 -NaCl-NaOH) and pH m (-log[H + ] = 8.5-14.5). Strongly reducing conditions (pe + pH m ≈ 2) were set with Sn(ii). Carbonate enhances the solubility of Tc(iv) in alkaline conditions by up to 3.5 log 10 -units compared to carbonate-free systems. Solvent extraction and XANES confirmed that Tc was kept as +IV during the timeframe of the experiments (≤ 650 days). Solid phase characterization performed by XAFS, XRD, SEM-EDS, chemical analysis and TG-DTA confirmed that TcO 2 ·0.6H 2 O(am) controls the solubility of Tc(iv) under the conditions investigated. Slope analysis of the solubility data in combination with solid/aqueous phase characterization and DFT calculations indicate the predominance of the species Tc(OH) 3 CO 3 - at pH m ≤ 11 and C tot ≥ 0.01 M, for which thermodynamic and activity models are derived. Solubility data obtained above pH m ≈ 11 indicates the formation of previously unreported Tc(iv)-carbonate species, possibly Tc(OH) 4 CO 3 2- , although the likely formation of additional complexes prevents deriving a thermodynamic model valid for this pH m -region. This work provides the most comprehensive thermodynamic dataset available for the system Tc 4+ -Na + -Cl - -OH - -HCO 3 - -CO 3 2- -H 2 O(l) valid under a range of conditions relevant for nuclear waste disposal.
Overview of ATLAS PanDA Workload Management

NASA Astrophysics Data System (ADS)

Maeno, T.; De, K.; Wenaus, T.; Nilsson, P.; Stewart, G. A.; Walker, R.; Stradling, A.; Caballero, J.; Potekhin, M.; Smith, D.; ATLAS Collaboration

2011-12-01

The Production and Distributed Analysis System (PanDA) plays a key role in the ATLAS distributed computing infrastructure. All ATLAS Monte-Carlo simulation and data reprocessing jobs pass through the PanDA system. We will describe how PanDA manages job execution on the grid using dynamic resource estimation and data replication together with intelligent brokerage in order to meet the scaling and automation requirements of ATLAS distributed computing. PanDA is also the primary ATLAS system for processing user and group analysis jobs, bringing further requirements for quick, flexible adaptation to the rapidly evolving analysis use cases of the early datataking phase, in addition to the high reliability, robustness and usability needed to provide efficient and transparent utilization of the grid for analysis users. We will describe how PanDA meets ATLAS requirements, the evolution of the system in light of operational experience, how the system has performed during the first LHC data-taking phase and plans for the future.
Overview of ATLAS PanDA Workload Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maeno T.; De K.; Wenaus T.

2011-01-01

The Production and Distributed Analysis System (PanDA) plays a key role in the ATLAS distributed computing infrastructure. All ATLAS Monte-Carlo simulation and data reprocessing jobs pass through the PanDA system. We will describe how PanDA manages job execution on the grid using dynamic resource estimation and data replication together with intelligent brokerage in order to meet the scaling and automation requirements of ATLAS distributed computing. PanDA is also the primary ATLAS system for processing user and group analysis jobs, bringing further requirements for quick, flexible adaptation to the rapidly evolving analysis use cases of the early datataking phase, in additionmore » to the high reliability, robustness and usability needed to provide efficient and transparent utilization of the grid for analysis users. We will describe how PanDA meets ATLAS requirements, the evolution of the system in light of operational experience, how the system has performed during the first LHC data-taking phase and plans for the future.« less
The Na+-Responsive ntp Operon Is Indispensable for Homeostatis of K+ and Na+ in Enterococcus hirae at Limited Proton Potential

PubMed Central

Kawano, Miyuki; Igarashi, Kazuei; Kakinuma, Yoshimi

1998-01-01

Enterococcus hirae ATCC 9790 grew well in Na+-deficient, low-K+ medium, but growth was inhibited by carbonylcyanide m-chlorophenylhydrazone (CCCP). Growth inhibition and decrease of cellular K+ levels in the presence of CCCP were relieved by the addition of Na+ and a high concentration of K+. In contrast, in the mutant defective in Na+-ATPase or the NtpJ component of the KtrII K+ uptake system, CCCP-induced growth inhibition was rescued by a high concentration of K+ but not of Na+. These transporters are thus indispensable for homeostatis of K+ and Na+ at low proton potential. PMID:9733699
Vi-da: vitiligo diagnostic assistance mobile application

NASA Astrophysics Data System (ADS)

Nugraha, G. A.; Nurhudatiana, A.; Bahana, R.

2018-03-01

Vitiligo is a skin disorder in which white patches of depigmentation appear on different parts of the body. Usually, patients come to hospitals or clinics to have their vitiligo conditions assessed. This can be very tiring to the patients, as vitiligo treatments usually take a relatively long period of time, which can range from months to years. To address this challenge, we present in this paper a prototype of an Android-based mobile application called Vi-DA, which stands for Vitiligo Diagnostic Assistance. Vi-DA consists of three subsystems, which are user sign-up subsystem, camera and image analysis subsystem, and progress report subsystem. The mobile application was developed in Java programming language and uses MySQL as the database system. Vi-DA adopts a vitiligo segmentation algorithm to segment input image into normal skin area, vitiligo skin area, and non-skin area. Results showed that Vi-DA gave comparable results to the previous system implemented in Matlab. User acceptance testing results also showed that all respondents agreed on the usefulness of the system and agreed to use Vi-DA again in the future. Vi-DA benefits both dermatologists and patients as not only a computer-aided diagnosis (CAD) tool but also as a smart application that can be used for self-assessment at home.
Elevation as a barrier: genetic structure for an Atlantic rain forest tree (Bathysa australis) in the Serra do Mar mountain range, SE Brazil.

PubMed

Reis, Talita Soares; Ciampi-Guillardi, Maísa; Bajay, Miklos Maximiliano; de Souza, Anete Pereira; Dos Santos, Flavio Antonio Maës

2015-05-01

Distance and discrete geographic barriers play a role in isolating populations, as seed and pollen dispersal become limited. Nearby populations without any geographic barrier between them may also suffer from ecological isolation driven by habitat heterogeneity, which may promote divergence by local adaptation and drift. Likewise, elevation gradients may influence the genetic structure and diversity of populations, particularly those marginally distributed. Bathysa australis (Rubiaceae) is a widespread tree along the elevation gradient of the Serra do Mar, SE Brazil. This self-compatible species is pollinated by bees and wasps and has autochoric seeds, suggesting restricted gene dispersal. We investigated the distribution of genetic diversity in six B. australis populations at two extreme sites along an elevation gradient: a lowland site (80-216 m) and an upland site (1010-1100 m.a.s.l.). Nine microsatellite loci were used to test for genetic structure and to verify differences in genetic diversity between sites. We found a marked genetic structure on a scale as small as 6 km (F ST = 0.21), and two distinct clusters were identified, each corresponding to a site. Although B. australis is continuously distributed along the elevation gradient, we have not observed a gene flow between the extreme populations. This might be related to B. australis biological features and creates a potential scenario for adaptation to the different conditions imposed by the elevation gradient. We failed to find an isolation-by-distance pattern; although on the fine scale, all populations showed spatial autocorrelation until ∼10-20 m. Elevation difference was a relevant factor though, but we need further sampling effort to check its correlation with genetic distance. The lowland populations had a higher allelic richness and showed higher rare allele counts than the upland ones. The upland site may be more selective, eliminating rare alleles, as we did not find any evidence for
Growth and characterization of struvite-Na crystals

NASA Astrophysics Data System (ADS)

Chauhan, Chetan K.; Joshi, Mihirkumar J.

2014-09-01

Sodium magnesium phosphate heptahydrate [NaMgPO4·7H2O], also known as struvite-Na, is the sodium analog to struvite. Among phosphate containing bio-minerals, struvite has attracted considerable attention, because of its common occurrence in a wide variety of environments. Struvite and family crystals were found as urinary calculi in humans and animals. Struvite-Na crystals were grown by a single diffusion gel growth technique in a silica hydro gel medium. Struvite-Na crystals with different morphologies having transparent to translucent diaphaneity were grown with different growth parameters. The phenomenon of Liesegang rings was also observed with some particular growth parameters. The powder XRD study confirmed the structural similarity of the grown struvite-Na crystals with struvite and found that struvite-Na crystallized in the orthorhombic Pmn21 space group with unit cell parameters such as a= 6.893 Å, b=6.124 Å, c=11.150 Å, and α=β=γ=90°. FT-IR spectra of struvite-Na crystals revealed the presence of functional groups. The TGA, DTA and DSC were carried out simultaneously. The kinetic and thermodynamic parameters of dehydration/decomposition process were calculated. The variation of dielectric constant with frequency of applied field was studied in the range from 400 Hz to 100 kHz.
Metaproteomics of Microbiota in Naturally Fermented Soybean Paste, Da-jiang.

PubMed

Zhang, Ping; Zhang, Pengfei; Xie, Mengxi; An, Feiyu; Qiu, Boshu; Wu, Rina

2018-05-01

Da-jiang is a typical traditional fermented soybean product in China. At present, the proteins in da-jiang are needed to be explored. The composition and species of microbial proteins in traditional fermented da-jiang were analyzed by metaproteomics based on sodium dodecyl sulfonate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The results showed that the number and variety of microbial proteins in the traditional fermented da-jiang from different regions were different. The production site influences the fermentation in da-jiang. Then we analyzed the functions of the microbial proteins identified in da-jiang, and found that they were mainly involved in the process of protein synthesis, glycometabolism and nucleic acid synthesis. In addtion, we compared the proteins composition in different da-jiang. There are 51 common proteins of naturally fermented da-jiang, and 25 common microbial sources. The main commonly microbial sources of fungal proteins are Saccharomyces cerevisiae and Schizosaccharomyces; the main commonly microbial sources of bacterial proteins are Enterococcus faecalis, Leuconostoc mesenteroides, Acinetobacter baumannii, and Bacillus subtilis. These common microbes play the predominant role in da-jiang fermentation. The present results help us to understand the fermentation of da-jiang and improve the quality and safety of final products in the future. The study illustrated metaproteome of microbiota in traditional fermented soybean paste, da-jiang, by sodium dodecyl sulfonate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). A method of extracting metaproteome from microbiota in da-jiang was attempted. The findings help to understand the fermentation of da-jiang and improve the quality and safety of da-jiang in fermented industry. © 2018 Institute of Food Technologists®.
23Na and 35/37Cl as NMR probes of growth and shape of sodium taurodeoxycholate micellar aggregates in the presence of NaCl.

PubMed

Asaro, Fioretta; Feruglio, Luigi; Galantini, Luciano; Nardelli, Alessia

2013-02-15

The growth of the aggregates of the dihydroxylated bile salt sodium taurodeoxycholate (NaTDC) upon NaCl addition and the involvement of the counterion were investigated by NMR spectroscopy of monoatomic ionic species. (23)Na T(1) values from 0.015, 0.100, and 0.200 mol kg(-1) NaTDC solutions in D(2)O, at variable NaCl content, proved to be sensitive to the transition from primary to secondary aggregates, which occurs in the former sample, and to intermicellar interaction. Some (79)Br NMR measurements were performed on a 0.100 mol kg(-1) NaTDC sample added by NaBr in place of NaCl for comparison purposes. The (23)Na, (35)Cl, and (37)Cl double quantum filtered (DQF) patterns, from the 0.100 mol kg(-1) NaTDC sample, and (23)Na ones also from the 0.200 mol kg(-1) NaTDC one, in the presence of 0.750 mol kg(-1) NaCl, are a clear manifestation of motional anisotropy. Moreover, the DQF spectra of (23)Na and (37)Cl, which possess close quadrupole moments, display a striking similarity. The DQF lineshapes were simulated exploiting the Scilab environment to obtain an estimate of the residual quadrupole splitting magnitude. These results support the description of NaTDC micelles as cylindrical aggregates, strongly interacting at high ionic strengths, and capable of association with added electrolytes. Copyright © 2012 Elsevier Inc. All rights reserved.
Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na 3OBr and Na 4OI 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yonggang; Wen, Ting; Park, Changyong

2016-01-14

The structure stability under high pressure and thermal expansion behavior of Na 3OBr and Na 4OI 2, two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temp. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na 3OBr and Na 4OI 2, resp. The cubic Na 3OBr structure and tetragonal Na 4OI 2 with intergrowth K 2NiF 4 structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na 4OI 2 exhibits nearly isotropic compressibility. Neg. thermal expansion wasmore » obsd. at low temp. range (20-80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined. and confirmed by first-principles calculations. among various possible polymorphisms qualitatively. The results provide in-depth understanding of the neg. thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications.« less
Europlanet NA2 Science Networking

NASA Astrophysics Data System (ADS)

Harri, Ari-Matti; Szego, Karoly; Genzer, Maria; Schmidt, Walter; Krupp, Norbert; Lammer, Helmut; Kallio, Esa; Haukka, Harri

2013-04-01

Europlanet RI / NA2 Science Networking [1] focused on determining the major goals of current and future European planetary science, relating them to the Research Infrastructure that the Europlanet RI project [2] developed, and placing them in a more global context. NA2 also enhanced the ability of European planetary scientists to participate on the global scene with their own agenda-setting projects and ideas. The Networking Activity NA2 included five working groups, aimed at identifying key science issues and producing reference books on major science themes that will bridge the gap between the results of present and past missions and the scientific preparation of the future ones. Within the Europlanet RI project (2009-2012) the NA2 and NA2-WGs organized thematic workshops, an expert exchange program and training groups to improve the scientific impact of this Infrastructure. The principal tasks addressed by NA2 were: • Science activities in support to the optimal use of data from past and present space missions, involving the broad planetary science community beyond the "space club" • Science activities in support to the preparation of future planetary missions: Earth-based preparatory observations, laboratory studies, R&D on advanced instrumentation and exploration technologies for the future, theory and modeling etc. • Develop scientific activities, joint publications, dedicated meetings, tools and services, education activities, engaging the public and industries • Update science themes and addressing the two main scientific objectives • Prepare and support workshops of the International Space Science Institute (ISSI) in Bern and • Support Trans National Activities (TNAs), Joined Research Activities (JRAs) and the Integrated and Distributed Information Service (IDIS) of the Europlanet project These tasks were achieved by WG workshops organized by the NA2 working groups, by ISSI workshops and by an Expert Exchange Program. There were 17 official WG
A sensitive analysis method for 7 diterpenoids in rat plasma by liquid chromatography-electrospray ionization mass spectrometry and its application to pharmacokinetic study of Isodon serra extract.

PubMed

Du, Yingfeng; Liu, Pengwei; Zhu, Hong; Shi, Xiaowei; Zhao, Chengcheng; Wang, Na; Zhang, Lantong

2011-10-28

A simple and sensitive LC-MS/MS method has been developed and validated for the identification and quantification of epinodosin, epinodosinol, nodosin, oridonin, lasiokariurinol, lasiokaurin and rabdoternin A in rat plasma using sulfamethoxazole as the internal standard. The plasma sample pre-treatment consisted of a liquid-liquid extraction. Chromatographic separation was achieved on a C18 column with linear gradient elution using water and methanol, which were both acidified with 0.1% formic acid, at a flow rate of 0.7 mL/min. A tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) via an electrospray ionization (ESI) source. A novel multi-determination-periods program was executed to achieve a higher sensitivity by setting five scanning periods. The method presented here utilizes a novel determination strategy, enabling the application of positive and negative ESI-MS in a single run. The optimized mass transition ion-pairs (m/z) for quantitation were 361.2/287.1 for epinodosin, 382.3/347.3 for epinodosinol, 363.3/281.2 for nodosin, 365.3/347.3 for oridonin, 407.3/329.1 for lasiokariurinol, 405.2/59.0 for lasiokaurin, 363.2/283.1 for rabdoternin A and 254.1/156.0 for IS. The total run time was 20.50 min (including 5 min equilibration time) between injections. The specificity, linearity, accuracy, precision, recovery, matrix effect and several validation results demonstrate that this method is sensitive, specific and reliable. The proposed method was further applied to investigate the pharmacokinetics of all analytes after a single oral administration of Isodon serra extract to rats. Copyright © 2011 Elsevier B.V. All rights reserved.
Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium.

PubMed

Cano, Mercedes; Calonge, María L; Ilundáin, Anunciación A

2015-10-01

The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1±0.5 mM and its maximal transport velocity, Vmax, 0.5±0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are L-proline (75%) and cold betaine, L-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47±7 μM and a Vmax of 7.8±1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either L-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system. Copyright © 2015 Elsevier B.V. All rights reserved.
Fabrication of Na0.7MnO2/C composite cathode material by simple heat treatment for high-power na-ion batteries

NASA Astrophysics Data System (ADS)

Sohn, DongRak; Lim, Sung-Jin; Nam, Do-Hwan; Hong, Kyung-Sik; Kim, Tae-Hee; Oh, SeKwon; Eom, Ji-Yong; Cho, EunAe; Kwon, HyukSang

2018-01-01

A Na0.7MnO2/C composite cathode material is synthesized by simple and costeffective two-step heat treatment for an improvement in the rate capability of Na0.7MnO2. The first heat treatment is to synthesize Na0.7MnO2, and the second one is a low temperature annealing at 350 °C for 1 h in air, which is necessary to suppress an interfacial reaction between the Na0.7MnO2 and C in the synthesis process of Na0.7MnO2/C composite. Structural analyses by XRD and XPS reveal that the Na0.7MnO2/C shows the same structural properties as that of the pristine Na0.7MnO2, and hence they exhibit the same initial discharge capacity of 175 mAh g-1 at 20 mA g-1. At a current density of 400 mA g-1, the discharge capacity of Na0.7MnO2 reduces to 50 mAh g-1 (28% of the initial discharge capacity), whereas that of Na0.7MnO2/C reduces to 108 mAh g-1 (61% of the initial discharge capacity). The enhanced rate capability of the Na0.7MnO2/C is attributed to the conductive carbon layer formed on the surface of Na0.7MnO2 particles, enabling the facile transport of electrons from the current collector to the surface of the Na0.7MnO2 particles. [Figure not available: see fulltext.
Dramatic increase in naïve T cell turnover is linked to loss of naïve T cells from old primates

PubMed Central

Čičin-Šain, Luka; Messaoudi, Ilhem; Park, Byung; Currier, Noreen; Planer, Shannon; Fischer, Miranda; Tackitt, Shane; Nikolich-Žugich, Dragana; Legasse, Alfred; Axthelm, Michael K.; Picker, Louis J.; Mori, Motomi; Nikolich-Žugich, Janko

2007-01-01

The loss of naïve T cells is a hallmark of immune aging. Although thymic involution is a primary driver of this naïve T cell loss, less is known about the contribution of other mechanisms to the depletion of naïve T cells in aging primates. We examined the role of homeostatic cycling and proliferative expansion in different T cell subsets of aging rhesus macaques (RM). BrdU incorporation and the expression of the G1-M marker Ki-67 were elevated in peripheral naïve CD4 and even more markedly in the naïve CD8 T cells of old, but not young adult, RM. Proliferating naïve cells did not accumulate in old animals. Rather, the relative size of the naïve CD8 T cell compartment correlated inversely to its proliferation rate. Likewise, T cell receptor diversity decreased in individuals with elevated naïve CD8 T cell proliferation. This apparent contradiction was explained by a significant increase in turnover concomitant with the naïve pool loss. The turnover increased exponentially when the naïve CD8 T cell pool decreased below 4% of total blood CD8 cells. These results link the shrinking naïve T cell pool with a dramatic increase in homeostatic turnover, which has the potential to exacerbate the progressive exhaustion of the naïve pool and constrict the T cell repertoire. Thus, homeostatic T cell proliferation exhibits temporal antagonistic pleiotropy, being beneficial to T cell maintenance in adulthood but detrimental to the long-term T cell maintenance in aging individuals. PMID:18056811
Na0.44MnO2 nanorods as a cathode material for Na-ion batteries

NASA Astrophysics Data System (ADS)

Avci, Sevda; Oz, Erdinc; Demirel, Serkan; Altin, Emine; Altin, Serdar; Bayri, Ali; Yakinci, Eyyuphan

2014-03-01

Lithium-ion batteries have dominated the rechargeable battery market because of their high energy and power capability. On the other hand, sodium is one of the more abundant elements on Earth unlike Li. Moreover, Na has similar chemical properties to Li, indicating that Na-ion batteries can be an alternative to Li counterparts. With that respect, we have synthesized Na0.44MnO2 nanorods as cathode materials for Na-ion batteries. We have investigated the effects of structural, electrical, and magnetic properties on battery performance. We report the synthesis conditions and growth mechanism of the nanorods. The structure and the morphology of the materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and atomic force microscopy (AFM) techniques. Temperature dependent structural changes were determined via in situ X-ray diffraction and TG-DTA measurements showing structural changes above room temperature. This work is funded by The Scientific and Technological Research Council of Turkey with Grant No:112M487.
Modulation of contraction by intracellular Na+ via Na(+)-Ca2+ exchange in single shark (Squalus acanthias) ventricular myocytes.

PubMed Central

Näbauer, M; Morad, M

1992-01-01

1. The effect of direct alteration of intracellular Na+ concentration on contractile properties of whole-cell clamped shark ventricular myocytes was studied using an array of 256 photodiodes to monitor the length of the isolated myocytes. 2. In myocytes dialysed with Na(+)-free solution, the voltage dependence of Ca2+ current (ICa) and contraction were similar and bell shaped. Contractions activated at all voltages were completely suppressed by nifedipine (5 microM), and failed to show significant tonic components, suggesting dependence of the contraction on Ca2+ influx through the L-type Ca2+ channel. 3. In myocytes dialysed with 60 mM Na+, a ICa-dependent and a ICa-independent component of contraction could be identified. The Ca2+ current-dependent component was prominent in voltages between -30 to +10 mV. The ICa-independent contractions were maintained for the duration of depolarization, increased with increasing depolarization between +10 to +100 mV, and were insensitive to nifedipine. 4. In such myocytes, repolarization produced slowly decaying inward tail currents closely related to the time course of relaxation and the degree of shortening prior to repolarization. 5. With 60 mM Na+ in the pipette solution, positive clamp potentials activated decaying outward currents which correlated to the size of contraction. These outward currents appeared to be generated by the Na(+)-Ca(2+)-exchanger since they depended on the presence of intracellular Na+, and were neither suppressed by nifedipine nor by K+ channel blockers. 6. The results suggest that in shark (Squalus acanthias) ventricular myocytes, which lack functionally relevant Ca2+ release pools, both Ca2+ channel and the Na(+)-Ca2+ exchanger deliver sufficient Ca2+ to activate contraction, though the effectiveness of the latter mechanism was highly dependent on the [Na+]i. PMID:1338467

Hot-corrosion of AISI 1020 steel in a molten NaCl/Na2SO4 eutectic at 700°C

NASA Astrophysics Data System (ADS)

Badaruddin, Mohammad; Risano, Ahmad Yudi Eka; Wardono, Herry; Asmi, Dwi

2017-01-01

Hot-corrosion behavior and morphological development of AISI 1020 steel with 2 mg cm-2 mixtures of various NaCl/Na2SO4 ratios at 700°C were investigated by means of weight gain measurements, Optical Microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The weight gain kinetics of the steel with mixtures of salt deposits display a rapid growth rates, compared with the weight gain kinetics of AISI 1020 steel without salt deposit in dry air oxidation, and follow a steady-state parabolic law for 49 h. Chloridation and sulfidation produced by a molten NaCl/Na2SO4 on the steel induced hot-corrosion mechanism attack, and are responsible for the formation of thicker scale. The most severe corrosion takes place with the 70 wt.% NaCl mixtures in Na2SO4. The typical Fe2O3 whisker growth in outer part scale was attributed to the FeCl3 volatilization. The formation of FeS in the innermost scale is more pronounced as the content of Na2SO4 in the mixture is increased.
Regulation of Epithelial Sodium Transport via Epithelial Na+ Channel

PubMed Central

Marunaka, Yoshinori; Niisato, Naomi; Taruno, Akiyuki; Ohta, Mariko; Miyazaki, Hiroaki; Hosogi, Shigekuni; Nakajima, Ken-ichi; Kusuzaki, Katsuyuki; Ashihara, Eishi; Nishio, Kyosuke; Iwasaki, Yoshinobu; Nakahari, Takashi; Kubota, Takahiro

2011-01-01

Renal epithelial Na+ transport plays an important role in homeostasis of our body fluid content and blood pressure. Further, the Na+ transport in alveolar epithelial cells essentially controls the amount of alveolar fluid that should be kept at an appropriate level for normal gas exchange. The epithelial Na+ transport is generally mediated through two steps: (1) the entry step of Na+ via epithelial Na+ channel (ENaC) at the apical membrane and (2) the extrusion step of Na+ via the Na+, K+-ATPase at the basolateral membrane. In general, the Na+ entry via ENaC is the rate-limiting step. Therefore, the regulation of ENaC plays an essential role in control of blood pressure and normal gas exchange. In this paper, we discuss two major factors in ENaC regulation: (1) activity of individual ENaC and (2) number of ENaC located at the apical membrane. PMID:22028593
[Trattamento del disturbo da uso di alcol da un punto di vista psicologico].

PubMed

Coriale, Giovanna; Fiorentino, Daniela; De Rosa, Francesca; Solombrino, Simona; Scalese, Bruna; Ciccarelli, Rosaria; Attilia, Fabio; Vitali, Mario; Musetti, Alessia; Fiore, Marco; Ceccanti, Mauro

2018-01-01

RIASSUNTO. L'elaborazione del piano di trattamento rappresenta un momento molto delicato e complesso del processo terapeutico del disturbo da abuso di alcol (DUA). È la fase in cui le informazioni raccolte da un'équipe di professionisti (medici, psicologi e assistenti sociali) (modello bio-psico-sociale del DUA) vengono messe insieme per decidere il percorso terapeutico più adatto. Per quanto riguarda la parte psicologica, è di notevole importanza scegliere un trattamento clinico in grado di ridurre al minimo la mancata adesione al trattamento e, per i soggetti che rimangono in trattamento, di garantirne l'efficacia. Se da una parte, le tecniche psicoanalitiche e comportamentali hanno fornito le basi della terapia psicologica dell'alcolismo, dall'altra, gli approcci basati sull'evidenza scientifica sono stati elaborati a partire dai principi del colloquio motivazionale e della terapia cognitivo-comportamentale. In questo articolo viene fornita una panoramica dei trattamenti che sono risultati più efficaci nel trattare il DUA e delle modalità temporali più adeguate per monitorare l'efficacia del trattamento.
Multiple quantum filtered 23Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i

PubMed Central

Eykyn, Thomas R.; Aksentijević, Dunja; Aughton, Karen L.; Southworth, Richard; Fuller, William; Shattock, Michael J.

2015-01-01

We investigate the potential of multiple quantum filtered (MQF) 23Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32 ± 6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the 23Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM3SA mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered 23Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation. PMID:26196304
Evaluation of the Efficacy and Safety of DA-9601 versus Its New Formulation, DA-5204, in Patients with Gastritis: Phase III, Randomized, Double-Blind, Non-Inferiority Study.

PubMed

Choi, Yoon Jin; Lee, Dong Ho; Choi, Myung Gyu; Lee, Sung Joon; Kim, Sung Kook; Song, Geun Am; Rhee, Poong Lyul; Jung, Hwoon Yong; Kang, Dae Hwan; Lee, Yong Chan; Lee, Si Hyung; Choi, Suck Chei; Shim, Ki Nam; Seol, Sang Yong; Moon, Jeong Seop; Shin, Yong Woon; Kim, Hyun Soo; Lee, Soo Teik; Cho, Jin Woong; Choi, Eun Kwang; Lee, Oh Young; Jang, Jin Seok

2017-11-01

This study compared the efficacy of DA-9601 (Dong-A ST Co., Seoul, Korea) and its new formulation, DA-5204 (Dong-A ST Co.), for treating erosive gastritis. This phase III, randomized, multicenter, double-blind, non-inferiority trial randomly assigned 434 patients with endoscopically proven gastric mucosal erosions into two groups: DA-9601 3 times daily or DA-5,204 twice daily for 2 weeks. The final analysis included 421 patients (DA-5204, 209; DA-9601, 212). The primary endpoint (rate of effective gastric erosion healing) and secondary endpoints (cure rate of endoscopic erosion and gastrointestinal [GI] symptom relief) were assessed using endoscopy after the treatment. Drug-related adverse events (AEs), including GI symptoms, were also compared. At week 2, gastric healing rates with DA-5204 and DA-9601 were 42.1% (88/209) and 42.5% (90/212), respectively. The difference between the groups was -0.4% (95% confidence interval, -9.8% to 9.1%), which was above the non-inferiority margin of -14%. The cure rate of gastric erosion in both groups was 37.3%. The improvement rates of GI symptoms with DA-5204 and DA-9601 were 40.4% and 40.8%, respectively. There were no statistically significant differences between the two groups in both secondary endpoints. AEs were reported in 18 (8.4%) patients in the DA-5204 group and 19 (8.8%) in the DA-9601 group. Rates of AE were not different between the two groups. No serious AE or adverse drug reaction (ADR) occurred. These results demonstrate the non-inferiority of DA-5204 compared to DA-9601. DA-5204 is as effective as DA-9601 in the treatment of erosive gastritis. Registered randomized clinical trial at ClinicalTrials.gov (NCT02282670). © 2017 The Korean Academy of Medical Sciences.
Hydrogen production by sodium borohydride in NaOH aqueous solution

NASA Astrophysics Data System (ADS)

Wang, Q.; Zhang, L. F.; Zhao, Z. G.

2018-01-01

The kinetics of hydrolysis reaction of NaBH4 in NaOH aqueous solution is studied. The influence of pH of the NaOH aqueous solution on the rate of hydrogen production and the hydrogen production efficiency are studied for the hydrolysis reaction of NaBH4. The results show that the activation energy of hydrolysis reaction of NaBH4 increased with the increase of the initial pH of NaOH aqueous solution.With the increasing of the initial pH of NaOH aqueous solution, the rate of hydrogen production and hydrogen production efficiency of NaBH4 hydrolysis decrease.
Volume Transmission in Central Dopamine and Noradrenaline Neurons and Its Astroglial Targets.

PubMed

Fuxe, Kjell; Agnati, Luigi F; Marcoli, Manuela; Borroto-Escuela, Dasiel O

2015-12-01

Already in the 1960s the architecture and pharmacology of the brainstem dopamine (DA) and noradrenaline (NA) neurons with formation of vast numbers of DA and NA terminal plexa of the central nervous system (CNS) indicated that they may not only communicate via synaptic transmission. In the 1980s the theory of volume transmission (VT) was introduced as a major communication together with synaptic transmission in the CNS. VT is an extracellular and cerebrospinal fluid transmission of chemical signals like transmitters, modulators etc. moving along energy gradients making diffusion and flow of VT signals possible. VT interacts with synaptic transmission mainly through direct receptor-receptor interactions in synaptic and extrasynaptic heteroreceptor complexes and their signaling cascades. The DA and NA neurons are specialized for extrasynaptic VT at the soma-dendrtitic and terminal level. The catecholamines released target multiple DA and adrenergic subtypes on nerve cells, astroglia and microglia which are the major cell components of the trophic units building up the neural-glial networks of the CNS. DA and NA VT can modulate not only the strength of synaptic transmission but also the VT signaling of the astroglia and microglia of high relevance for neuron-glia interactions. The catecholamine VT targeting astroglia can modulate the fundamental functions of astroglia observed in neuroenergetics, in the Glymphatic system, in the central renin-angiotensin system and in the production of long-distance calcium waves. Also the astrocytic and microglial DA and adrenergic receptor subtypes mediating DA and NA VT can be significant drug targets in neurological and psychiatric disease.
VerSeDa: vertebrate secretome database

PubMed Central

Cortazar, Ana R.; Oguiza, José A.

2017-01-01

Based on the current tools, de novo secretome (full set of proteins secreted by an organism) prediction is a time consuming bioinformatic task that requires a multifactorial analysis in order to obtain reliable in silico predictions. Hence, to accelerate this process and offer researchers a reliable repository where secretome information can be obtained for vertebrates and model organisms, we have developed VerSeDa (Vertebrate Secretome Database). This freely available database stores information about proteins that are predicted to be secreted through the classical and non-classical mechanisms, for the wide range of vertebrate species deposited at the NCBI, UCSC and ENSEMBL sites. To our knowledge, VerSeDa is the only state-of-the-art database designed to store secretome data from multiple vertebrate genomes, thus, saving an important amount of time spent in the prediction of protein features that can be retrieved from this repository directly. Database URL: VerSeDa is freely available at http://genomics.cicbiogune.es/VerSeDa/index.php PMID:28365718
VerSeDa: vertebrate secretome database.

PubMed

Cortazar, Ana R; Oguiza, José A; Aransay, Ana M; Lavín, José L

2017-01-01

Based on the current tools, de novo secretome (full set of proteins secreted by an organism) prediction is a time consuming bioinformatic task that requires a multifactorial analysis in order to obtain reliable in silico predictions. Hence, to accelerate this process and offer researchers a reliable repository where secretome information can be obtained for vertebrates and model organisms, we have developed VerSeDa (Vertebrate Secretome Database). This freely available database stores information about proteins that are predicted to be secreted through the classical and non-classical mechanisms, for the wide range of vertebrate species deposited at the NCBI, UCSC and ENSEMBL sites. To our knowledge, VerSeDa is the only state-of-the-art database designed to store secretome data from multiple vertebrate genomes, thus, saving an important amount of time spent in the prediction of protein features that can be retrieved from this repository directly. VerSeDa is freely available at http://genomics.cicbiogune.es/VerSeDa/index.php. © The Author(s) 2017. Published by Oxford University Press.
Neurobiological support to the diagnosis of ADHD in stimulant-naïve adults: pattern recognition analyses of MRI data.

PubMed

Chaim-Avancini, T M; Doshi, J; Zanetti, M V; Erus, G; Silva, M A; Duran, F L S; Cavallet, M; Serpa, M H; Caetano, S C; Louza, M R; Davatzikos, C; Busatto, G F

2017-12-01

In adulthood, the diagnosis of attention-deficit/hyperactivity disorder (ADHD) has been subject of recent controversy. We searched for a neuroanatomical signature associated with ADHD spectrum symptoms in adults by applying, for the first time, machine learning-based pattern classification methods to structural MRI and diffusion tensor imaging (DTI) data obtained from stimulant-naïve adults with childhood-onset ADHD and healthy controls (HC). Sixty-seven ADHD patients and 66 HC underwent high-resolution T1-weighted and DTI acquisitions. A support vector machine (SVM) classifier with a non-linear kernel was applied on multimodal image features extracted on regions of interest placed across the whole brain. The discrimination between a mixed-gender ADHD subgroup and individually matched HC (n = 58 each) yielded area-under-the-curve (AUC) and diagnostic accuracy (DA) values of up to 0.71% and 66% (P = 0.003) respectively. AUC and DA values increased to 0.74% and 74% (P = 0.0001) when analyses were restricted to males (52 ADHD vs. 44 HC). Introvert personality traits showed independent risk effects on suicidality regardless of diagnosis status. Among high risk individuals with suicidal thoughts, higher neuroticism tendency is further associated with increased risk of suicide attempt. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
The Moon Phases in a Paper Box. (Spanish Title: Las Fases de la Luna en Una Caja de Cartón.) As Fases da Lua Numa Caixa de Papelão

NASA Astrophysics Data System (ADS)

de Fátima O. Saraiva, Maria; Amador, Cláudio B.; Kemper, Érico; Goulart, Paulo; Muller, Angela

2007-12-01

material didático de baixo custo para demonstração do conceito de fases de um corpo iluminado. O principal objetivo de nosso material é facilitar a compreensão das fases da Lua da perspectiva de um observador na Terra. O material ajuda na visualização de dois efeitos importantes: (1º) mesmo tendo sempre a metade da "Lua" (representada por uma bolinha de isopor ou de ping-pong) iluminada pelo "Sol" (representado por uma fonte de luz natural ou artificial), nós vemos diferentes frações de sua superfície iluminada, dependendo do ângulo pelo qual a olhamos; (2º) a orientação da borda convexa da Lua nas fases Crescente e Minguante também depende da perspectiva pela qual a olhamos da Terra. O uso de uma caixa fechada permite observar o contraste entre as diferentes fases sem necessidade de estar em uma sala escurecida. Apresentamos também um texto explicativo sobre fases da Lua, enfatizando a dependência da aparência da parte iluminada com o ângulo de visada.
Coulomb excitation of radioactive 20, 21Na

NASA Astrophysics Data System (ADS)

Schumaker, M. A.; Cline, D.; Hackman, G.; Pearson, C.; Svensson, C. E.; Wu, C. Y.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Becker, J. A.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Lisetskiy, A. F.; Leach, K. G.; Lee, G.; Maharaj, R.; Martin, J.-P.; Moisan, F.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Waddington, J. C.; Wan, J. M.; Whitbeck, A.; Williams, S. J.; Wong, J.

2009-12-01

The low-energy structures of the radioactive nuclei 20, 21Na have been examined using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ˜ 5×106 ions/s were accelerated to 1.7MeV/A and Coulomb excited in a 0.5mg/cm^2 natTi target. Two TIGRESS HPGe clover detectors perpendicular to the beam axis were used for γ -ray detection, while scattered nuclei were observed by the Si detector BAMBINO. For 21Na , Coulomb excitation from the 3/2+ ground state to the first excited 5/2+ state was observed, while for 20Na , Coulomb excitation was observed from the 2+ ground state to the first excited 3+ and 4+ states. For both beams, B ( λ L) values were determined using the 2+ rightarrow 0+ de-excitation in 48Ti as a reference. The resulting B( E2) ↓ value for 21Na is 137±9 e^2fm^4, while the resulting B( λ L) ↓ values for 20Na are 55±6 e^2fm^4 for the 3+ rightarrow 2+ , 35.7±5.7 e^2 fm^4 for the 4+ rightarrow 2+ , and 0.154±0.030 μ_ N^2 for the 4+ rightarrow 3+ transitions. This analysis significantly improves the measurement of the 21Na B( E2) value, and provides the first experimental determination of B( λ L) values for the proton dripline nucleus 20Na .-1
Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries

PubMed Central

Huang, Weifeng; Zhou, Jing; Li, Biao; Ma, Jin; Tao, Shi; Xia, Dingguo; Chu, Wangsheng; Wu, Ziyu

2014-01-01

Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V. PMID:24595232
Evaluating Landscape Connectivity for Puma concolor and Panthera onca Among Atlantic Forest Protected Areas

NASA Astrophysics Data System (ADS)

Castilho, Camila S.; Hackbart, Vivian C. S.; Pivello, Vânia R.; dos Santos, Rozely F.

2015-06-01

Strictly Protected Areas and riparian forests in Brazil are rarely large enough or connected enough to maintain viable populations of carnivores and animal movement over time, but these characteristics are fundamental for species conservation as they prevent the extinction of isolated animal populations. Therefore, the need to maintain connectivity for these species in human-dominated Atlantic landscapes is critical. In this study, we evaluated the landscape connectivity for large carnivores (cougar and jaguar) among the Strictly Protected Areas in the Atlantic Forest, evaluated the efficiency of the Mosaics of Protected Areas linked to land uses in promoting landscape connectivity, identified the critical habitat connections, and predicted the landscape connectivity status under the implementation of legislation for protecting riparian forests. The method was based on expert opinion translated into land use and land cover maps. The results show that the Protected Areas are still connected by a narrow band of landscape that is permeable to both species and that the Mosaics of Protected Areas increase the amount of protected area but fail to increase the connectivity between the forested mountain ranges (Serra do Mar and Serra da Mantiqueira). Riparian forests greatly increase connectivity, more than tripling the cougars' priority areas. We note that the selection of Brazilian protected areas still fails to create connectivity among the legally protected forest remnants. We recommend the immediate protection of the priority areas identified that would increase the structural landscape connectivity for these large carnivores, especially paths in the SE/NW direction between the two mountain ranges.
Evaluating Landscape Connectivity for Puma concolor and Panthera onca Among Atlantic Forest Protected Areas.

PubMed

Castilho, Camila S; Hackbart, Vivian C S; Pivello, Vânia R; dos Santos, Rozely F

2015-06-01

Strictly Protected Areas and riparian forests in Brazil are rarely large enough or connected enough to maintain viable populations of carnivores and animal movement over time, but these characteristics are fundamental for species conservation as they prevent the extinction of isolated animal populations. Therefore, the need to maintain connectivity for these species in human-dominated Atlantic landscapes is critical. In this study, we evaluated the landscape connectivity for large carnivores (cougar and jaguar) among the Strictly Protected Areas in the Atlantic Forest, evaluated the efficiency of the Mosaics of Protected Areas linked to land uses in promoting landscape connectivity, identified the critical habitat connections, and predicted the landscape connectivity status under the implementation of legislation for protecting riparian forests. The method was based on expert opinion translated into land use and land cover maps. The results show that the Protected Areas are still connected by a narrow band of landscape that is permeable to both species and that the Mosaics of Protected Areas increase the amount of protected area but fail to increase the connectivity between the forested mountain ranges (Serra do Mar and Serra da Mantiqueira). Riparian forests greatly increase connectivity, more than tripling the cougars' priority areas. We note that the selection of Brazilian protected areas still fails to create connectivity among the legally protected forest remnants. We recommend the immediate protection of the priority areas identified that would increase the structural landscape connectivity for these large carnivores, especially paths in the SE/NW direction between the two mountain ranges.
Stratigraphy of fluvial sediment sequences and their palaeoenvironmental information in the foreland of the Serra dos Órgãos, southeastern Brazil

NASA Astrophysics Data System (ADS)

Kirchner, André; Nehren, Udo; Heinrich, Jürgen

2013-04-01

In the hinterland of Rio de Janeiro city the rivers Guapiaçu, Macacu and Iconha originate in the Serra dos Órgãos mountain range and drain into the Atlantic Ocean. Since their channelization in the 1950s, higher flow velocities caused an incision of the rivers into the valley fills. These circumstances provide the possibility to study the alluvial deposits along the streams during low water level and allow conclusions on palaeoenvironmental change and landscape history. Sedimentological investigations of 13 exposures as well as AMS 14C measurements were carried out to investigate sediment properties and reconstruct the sedimentation history within the floodplains. These results enable to distinguish three different facies units. A late Pleistocene Unit I can be detected at the base of the observed exposures and consists of clast-supported fine to coarse gravels. It can be assumed that the gravel bodies were formed by a climatically induced erosional-depositional cycle within a braided river system. The gravels are overlaid by Unit II, a grayish to bluish loam mainly of mid-Holocene age. During generally drier climates these loams have been deposited during high water stages or flooding events as a splay facies proximal to the rivers. A reduced flow competence and relatively stable morphodynamic conditions are assumed for that period. Unit III accumulated in the late Holocene typically consists of several meters of planar or cross bedded sands to fine gravels, interfingered by loamy inclusions, buried peat bogs and organic debris. Fining-upward sequences can be frequently studied within Unit III which were completed by loamy sediments in the uppermost parts of the exposures. The increased flow competence from Unit II to Unit III seems to be a fluvial response to the increased humidity of the late Holocene as well as the enhancement of El Niño-Southern Oscillation (ENSO). Heavy rainfall likely caused higher sediment supply from the steep slopes as well as a
Biphasic voltage-dependent inactivation of human NaV 1.3, 1.6 and 1.7 Na+ channels expressed in rodent insulin-secreting cells.

PubMed

Godazgar, Mahdieh; Zhang, Quan; Chibalina, Margarita V; Rorsman, Patrik

2018-05-01

Na + current inactivation is biphasic in insulin-secreting cells, proceeding with two voltage dependences that are half-maximal at ∼-100 mV and -60 mV. Inactivation of voltage-gated Na + (Na V ) channels occurs at ∼30 mV more negative voltages in insulin-secreting Ins1 and primary β-cells than in HEK, CHO or glucagon-secreting αTC1-6 cells. The difference in inactivation between Ins1 and non-β-cells persists in the inside-out patch configuration, discounting an involvement of a diffusible factor. In Ins1 cells and primary β-cells, but not in HEK cells, inactivation of a single Na V subtype is biphasic and follows two voltage dependences separated by 30-40 mV. We propose that Na V channels adopt different inactivation behaviours depending on the local membrane environment. Pancreatic β-cells are equipped with voltage-gated Na + channels that undergo biphasic voltage-dependent steady-state inactivation. A small Na + current component (10-15%) inactivates over physiological membrane potentials and contributes to action potential firing. However, the major Na + channel component is completely inactivated at -90 to -80 mV and is therefore inactive in the β-cell. It has been proposed that the biphasic inactivation reflects the contribution of different Na V α-subunits. We tested this possibility by expression of TTX-resistant variants of the Na V subunits found in β-cells (Na V 1.3, Na V 1.6 and Na V 1.7) in insulin-secreting Ins1 cells and in non-β-cells (including HEK and CHO cells). We found that all Na V subunits inactivated at 20-30 mV more negative membrane potentials in Ins1 cells than in HEK or CHO cells. The more negative inactivation in Ins1 cells does not involve a diffusible intracellular factor because the difference between Ins1 and CHO persisted after excision of the membrane. Na V 1.7 inactivated at 15--20 mV more negative membrane potentials than Na V 1.3 and Na V 1.6 in Ins1 cells but this small difference is insufficient to solely
A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.

PubMed

Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu

2017-08-02

In order to study the dynamics of the reaction H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), a new potential energy surface (PES) for the ground state of the NaH 2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H 2 (X 1 Σ g + ) and NaH(X 1 Σ + ) obtained on the new NaH 2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH 2 system, the NaH 2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction. Because the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction releases more energy, the product molecules can be excited to a higher vibrational state.
The NA62 trigger system

NASA Astrophysics Data System (ADS)

Krivda, M.; NA62 Collaboration

2013-08-01

The main aim of the NA62 experiment (NA62 Technical Design Report, na62.web.cern.ch/NA62/Documents/TD_Full_doc_v1.pdf> [1]) is to study ultra-rare Kaon decays. In order to select rare events over the overwhelming background, central systems with high-performance, high bandwidth, flexibility and configurability are necessary, that minimize dead time while maximizing data collection reliability. The NA62 experiment consists of 12 sub-detector systems and several trigger and control systems, for a total channel count of less than 100,000. The GigaTracKer (GTK) has the largest number of channels (54,000), and the Liquid Krypton (LKr) calorimeter shares with it the largest raw data rate (19 GB/s). The NA62 trigger system works with 3 trigger levels. The first trigger level is based on a hardware central trigger unit, so-called L0 Trigger Processor (L0TP), and Local Trigger Units (LTU), which are all located in the experimental cavern. Other two trigger levels are based on software, and done with a computer farm located on surface. The L0TP receives information from triggering sub-detectors asynchronously via Ethernet; it processes the information, and then transmits a final trigger decision synchronously to each sub-detector through the Trigger and Timing Control (TTC) system. The interface between L0TP and the TTC system, which is used for trigger and clock distribution, is provided by the Local Trigger Unit board (LTU). The LTU can work in two modes: global and stand-alone. In the global mode, the LTU provides an interface between L0TP and TTC system. In the stand-alone mode, the LTU can fully emulate L0TP and so provides an independent way for each sub-detector for testing or calibration purposes. In addition to the emulation functionality, a further functionality is implemented that allows to synchronize the clock of the LTU with the L0TP and the TTC system. For testing and debugging purposes, a Snap Shot Memory (SSM) interface is implemented, that can work
Na7 [Fe2S6 ] , Na2 [FeS2 ] and Na2 [FeSe2 ] : New 'reduced' sodium chalcogenido ferrates

NASA Astrophysics Data System (ADS)

Stüble, Pirmin; Peschke, Simon; Johrendt, Dirk; Röhr, Caroline

2018-02-01

Three new 'reduced' FeII containing sodium chalcogenido ferrates were obtained applying a reductive synthetic route. The mixed-valent sulfido ferrate Na7 [Fe2S6 ] , which forms bar-shaped crystals with metallic greenish luster, was synthesized in pure phase from natural pyrite and elemental sodium at a maximum temperature of 800 °C. Its centrosymmetric triclinic structure (SG P 1 bar , a = 764.15(2), b = 1153.70(2), c = 1272.58(3) pm, α = 62.3325 (7) , β = 72.8345 (8) , γ = 84.6394 (8) ° , Z = 3, R1 = 0.0185) exhibits two crystallographically different [Fe2S6 ] 7 - dimers of edge-sharing [FeS4 ] tetrahedra, with somewhat larger Fe-S distances than in the fully oxidized FeIII dimers of e.g. Na6 [Fe2III S6 ] . In contrast to the localized AFM ordered pure di-ferrates(III), the Curie-Weiss behavior of the magnetic susceptibility proves the rarely observed valence-delocalized S = 9/2 state of the mixed-valent FeIII /FeII dimer. The nearly spin-only value of the magnetic moment combined with the chemical bonding not generally differing from that in pure ferrates(II) and (III), provides a striking argument, that the reduction of the local Fe spin moments observed in all condensed sulfido ferrate moieties is connected with the AFM spin ordering. The two isotypic ferrates(II) Na2 [FeS2 ] and Na2 [FeSe2 ] with chain-like structural units (SG Ibam, a = 643.54(8)/ 660.81(1), b = 1140.2(2)/1190.30(2) c = 562.90(6)/585.59(1) pm, Z = 4, R1 = 0.0372/0.0466) crystallize in the K2 [ZnO2 ] -type structure. Although representing merely further members of the common series of chalcogenido metallates(II) Na2 [MIIQ2 ] , these two new phases, together with Na6 [FeS4 ] and Li2 [FeS2 ] , are the only examples of pure FeII alkali chalcogenido ferrates. The new compounds allow for a general comparison of di- and chain ferrates(II) and (III) and mixed-valent analogs concerning the electronic and magnetic properties (including Heisenberg super-exchange and double-exchange interactions

Ranolazine vs phenytoin: greater effect of ranolazine on the transient Na(+) current than on the persistent Na(+) current in central neurons.

PubMed

Terragni, Benedetta; Scalmani, Paolo; Colombo, Elisa; Franceschetti, Silvana; Mantegazza, Massimo

2016-11-01

Voltage-gated Na(+) channels (NaV) are involved in pathologies and are important targets of drugs (NaV-blockers), e.g. some anti-epileptic drugs (AEDs). Besides the fast inactivating transient Na(+) current (INaT), they generate a slowly inactivating "persistent" current (INaP). Ranolazine, a NaV-blocker approved for treatment of angina pectoris, is considered a preferential inhibitor of INaP and has been proposed as a novel AED. Although it is thought that classic NaV-blockers used as AEDs target mainly INaT, they can also reduce INaP. It is important to disclose specific features of novel NaV-blockers, which could be necessary for their effect as AEDs in drug resistant patients. We have compared the action of ranolazine and of the classic AED phenytoin in transfected cells expressing the neuronal NaV1.1 Na(+) channel and in neurons of neocortical slices. Our results show that the relative block of INaT versus INaP of ranolazine and phenytoin is variable and depends on Na(+) current activation conditions. Strikingly, ranolazine blocks with less efficacy INaP and more efficacy INaT than phenytoin in conditions mimicking pathological states (i.e. high frequency firing and long lasting depolarizations). The effects are consistent with binding of ranolazine to both open/pre-open and inactivated states; larger INaT block at high stimulation frequencies is caused by the induction of a slow inactivated state. Thus, contrary than expected, ranolazine is not a better INaP blocker than phenytoin in central neurons, and phenytoin is not a better INaT blocker than ranolazine. Nevertheless, they show a complementary action and could differentially target specific pathological dysfunctions. Copyright © 2016 Elsevier Ltd. All rights reserved.
A semiclassical study of laser-induced atomic fluorescence from Na2, K2 and NaK

NASA Technical Reports Server (NTRS)

Yuan, J.-M.; Bhattacharyya, D. K.; George, T. F.

1982-01-01

A semiclassical treatment of laser-induced atomic fluorescence for the alkali-dimer systems Na2, K2 and NaK is presented. The variation of the fluorescence intensity with the frequency of the exciting laser photon is studied and a comparison of theoretical results with a set of experimental data is presented.
Na2O-Al2O3 system: Activity of Na2O in (α + β)- and (β + β)-alumina

NASA Astrophysics Data System (ADS)

Kale, G. M.

1992-12-01

The activity of Na2O in a biphasic mixture of (α + β)-alumina has been measured in the temperature range of 700 to 1100 K using the solid-state galvanic cell: 11663_2007_Article_BF02656462_TeX2GIFE1.gif _{(1:1)}^{Pt,CO_2 + O_2 /Na_2 CO_3 /(α + β ) - alumin a//(Y_2 O_3 )ZrO_2 //In + In_2 O_3 ,Ta,Pt} Similarly, the activity of Na2O in a (β + β’’)-alumina two-phase mixture has been measured between 700 and 1100 K employing the galvanic cell: 11663_2007_Article_BF02656462_TeX2GIFE2.gif _{(1:1)}^{Pt,CO_2 + O_2 /Na_2 CO_3 /(β + β ) - alumin a//(Y_2 O_3 )ZrO_2 //In + In_2 O_3 ,Ta,Pt} The reversible electromotive force (emf ) of both the cells was found to vary linearly with temperature over the entire temperature range of measurement. From the measured reversible emf and auxiliary thermodynamic data for In2O2, Na2O, CO2 and Na2CO3 reported in the literature, the temperature dependence of the logarithm of activity of Na2O in (α + β)-alumina is obtained: 11663_2007_Article_BF02656462_TeX2GIFE3.gif log α _{Na_2 O} (α + β ) = 1.85 - 14,750/T(K)( ± 0.015)(700 ≤slant T ≤slant 1100) For (β + β'’)-alumina, 11663_2007_Article_BF02656462_TeX2GIFE4.gif log α _{Na_2 O} (β + β ) = 3.9 - 13,000/T(K)( ± 0.015)(700 ≤slant T ≤slant 1100)
Redetermination of Na(3)TaF(8).

PubMed

Langer, Vratislav; Smrcok, Lubomír; Boca, Miroslav

2010-09-01

The crystal structure of trisodium octafluoridotantalate, Na(3)TaF(8), has been redetermined using diffractometer data collected at 153 K, resulting in more accurate bond distances and angles than obtained from a previous structure determination based on film data. The structure is built from layers running along [101], which are formed by distorted [TaF(8)] antiprisms and [NaF(6)] rectangular bipyramids sharing edges and corners. The individual layers are separated by eight-coordinated Na ions. Two atoms in the asymmetric unit are in special positions: the Ta atom is on a twofold axis in Wyckoff position 4e and one of the Na ions lies on an inversion centre in Wyckoff site 4d.
Na+/H+ exchange activity in the plasma membrane of Arabidopsis.

PubMed

Qiu, Quan-Sheng; Barkla, Bronwyn J; Vera-Estrella, Rosario; Zhu, Jian-Kang; Schumaker, Karen S

2003-06-01

In plants, Na+/H+ exchangers in the plasma membrane are critical for growth in high levels of salt, removing toxic Na+ from the cytoplasm by transport out of the cell. The molecular identity of a plasma membrane Na+/H+ exchanger in Arabidopsis (SOS1) has recently been determined. In this study, immunological analysis provided evidence that SOS1 localizes to the plasma membrane of leaves and roots. To characterize the transport activity of this protein, purified plasma membrane vesicles were isolated from leaves of Arabidopsis. Na+/H+ exchange activity, monitored as the ability of Na to dissipate an established pH gradient, was absent in plants grown without salt. However, exchange activity was induced when plants were grown in 250 mm NaCl and increased with prolonged salt exposure up to 8 d. H+-coupled exchange was specific for Na, because chloride salts of other monovalent cations did not dissipate the pH gradient. Na+/H+ exchange activity was dependent on Na (substrate) concentration, and kinetic analysis indicated that the affinity (apparent Km) of the transporter for Na+ is 22.8 mm. Data from two experimental approaches supports electroneutral exchange (one Na+ exchanged for one proton): (a) no change in membrane potential was measured during the exchange reaction, and (b) Na+/H+ exchange was unaffected by the presence or absence of a membrane potential. Results from this research provide a framework for future studies into the regulation of the plant plasma membrane Na+/H+ exchanger and its relative contribution to the maintenance of cellular Na+ homeostasis during plant growth in salt.
Estudo da região HII galática NGC 2579

NASA Astrophysics Data System (ADS)

Riffel, R.; Copetti, M. V. F.

2003-08-01

Desde a descoberta dos gradientes de abundância química em galáxias espirais, as regiões HII galáticas têm sido intensamente estudadas com o objetivo de determinar a forma do gradiente de abundância química na Via-Láctea. Entretanto, a forma do gradiente galático continua controversa e existem muitas regiões HII que continuam inexploradas. A região HII galática NGC 2579 é um objeto que aparece em imagens Ha, como uma pequena mancha brilhante de aproximadamente 2 segundos de arco de diâmetro a 20 segundos de arco ao leste de RCW 20, sendo NGC 2579 muitas vezes confundida com esta última. Apesar de seu alto brilho superficial, NGC 2579 é um objeto pouco estudado provavelmente por problemas de identificação deste objeto. Como parte de um projeto de reavaliação dos gradientes de abundância química das regiões HII na Via-Láctea, estamos realizando um estudo extensivo das propriedades físicas básicas como temperatura eletrônica, densidade eletrônica e composição química da região HII galática NGC 2579. Analisamos dados espectrofotométricos de fenda longa na faixa de 3700Å a 7750Å obtidos com o telescópio de 1.52 m do ESO, Chile, em 2002. Determinamos a temperatura eletrônica usando a razão entre as linhas do [OIII] (l4959+l5007/l4363) e a densidade eletrônica pela razão entre as linhas do [SII] (l6716/l6731). As abundâncias químicas do O, N, Cl, S, Ne e He foram determinadas. Realizamos um estudo de imagens fotométricas nas bandas UBVRI obtidas em 2000 no observatório astronômico San Pedro Mártir, México, para identificar e classificar as estrelas ionizantes de NGC 2579 e determinar a distância deste objeto.
Raven surgical robot training in preparation for da vinci.

PubMed

Glassman, Deanna; White, Lee; Lewis, Andrew; King, Hawkeye; Clarke, Alicia; Glassman, Thomas; Comstock, Bryan; Hannaford, Blake; Lendvay, Thomas S

2014-01-01

The rapid adoption of robotic assisted surgery challenges the pace at which adequate robotic training can occur due to access limitations to the da Vinci robot. Thirty medical students completed a randomized controlled trial evaluating whether the Raven robot could be used as an alternative training tool for the Fundamentals of Laparoscopic Surgery (FLS) block transfer task on the da Vinci robot. Two groups, one trained on the da Vinci and one trained on the Raven, were tested on a criterion FLS block transfer task on the da Vinci. After robotic FLS block transfer proficiency training there was no statistically significant difference between path length (p=0.39) and economy of motion scores (p=0.06) between the two groups, but those trained on the da Vinci did have faster task times (p=0.01). These results provide evidence for the value of using the Raven robot for training prior to using the da Vinci surgical system for similar tasks.
Construção de um catálogo de aglomerados abertos para estudo da dinâmica da estrutura espiral da Galáxia

NASA Astrophysics Data System (ADS)

Carlos, I. M.; Lépine, J. R. D.

2003-08-01

Os aglomerados abertos são objetos de grande valor para o estudo da dinâmica da Galáxia devido esses objetos terem uma faixa de idade relativamente ampla. O trabalho visa estudar a dinâmica da estrutura espiral da Galáxia principalmente através do uso desses aglomerados, uma vez que o estudo da cinemática desses objetos é fundamental para esse objetivo. Nosso grupo trabalha no sentido de construir uma base de dados de aglomerados abertos contendo coordenadas, distância, idade, movimentos próprios e velocidades radiais e já disponibiliza uma nova versão do catálogo de aglomerados abertos o qual é uma compilação de edições anteriores, principalmente Lynga (1987), Mermilliod (1995) e ESO-B (Lauberts 1982). Nossa amostra possui cerca de 1630 aglomerados, mas nem todos os parâmetros acima citados foram determinados em sua totalidade. Para determinarmos esses parâmetros, derivamos as cores intrínsecas das estrelas membro de cada aglomerado a partir de seus tipos espectrais (busca feita no SIMBAD) obtendo assim o excesso de cor individual. A distribuição dos excessos de cor foi então utilizada para derivarmos o avermelhamento médio para cada aglomerado. De maneira similar, os tipos espectrais foram usados para estimar as magnitudes absolutas, e com as magnitudes absolutas e aparentes determinamos a respectiva distribuição do módulo de distância e finalmente a distância. Para determinar as idades foram confeccionados os diagramas cor-magnitude das estrelas de cada aglomerado onde foram superpostas a Seqüência Principal de Idade Zero (ZAMS). Superpomos a ZAMS de Schmidt-Kaler e isócronas de composição solar. Essas isócronas foram usadas para determinação das idades dos aglomerados. Uma vez que não temos ainda resultados finais, apresentamos então alguns diagramas cor-magnitude os quais foram usados para determinação, principalmente, da distância e idade dos aglomerados.
Osmolality- and Na+ -dependent effects of hyperosmotic NaCl solution on contractile activity and Ca2+ cycling in rat ventricular myocytes.

PubMed

Ricardo, Rafael A; Bassani, Rosana A; Bassani, José W M

2008-01-01

Hypertonic NaCl solutions have been used for small-volume resuscitation from hypovolemic shock. We sought to identify osmolality- and Na(+)-dependent components of the effects of the hyperosmotic NaCl solution (85 mOsm/kg increment) on contraction and cytosolic Ca(2+) concentration ([Ca(2+)](i)) in isolated rat ventricular myocytes. The biphasic change in contraction and Ca(2+) transient amplitude (decrease followed by recovery) was accompanied by qualitatively similar changes in sarcoplasmic reticulum (SR) Ca(2+) content and fractional release and was mimicked by isosmotic, equimolar increase in extracellular [Na(+)] ([Na(+)](o)). Raising osmolality with sucrose, however, augmented systolic [Ca(2+)](i) monotonically without change in SR parameters and markedly decreased contraction amplitude and diastolic cell length. Functional SR inhibition with thapsigargin abolished hyperosmolality effects on [Ca(2+)](i). After 15-min perfusion, both hyperosmotic solutions slowed mechanical relaxation during twitches and [Ca(2+)](i) decline during caffeine-evoked transients, raised diastolic and systolic [Ca(2+)](i), and depressed systolic contractile activity. These effects were greater with sucrose solution, and were not observed after isosmotic [Na(+)](o) increase. We conclude that under the present experimental conditions, transmembrane Na(+) redistribution apparently plays an important role in determining changes in SR Ca(2+) mobilization, which markedly affect contractile response to hyperosmotic NaCl solutions and attenuate the osmotically induced depression of contractile activity.
Double Knockout of the Na+-Driven Cl-/HCO3- Exchanger and Na+/Cl- Cotransporter Induces Hypokalemia and Volume Depletion.

PubMed

Sinning, Anne; Radionov, Nikita; Trepiccione, Francesco; López-Cayuqueo, Karen I; Jayat, Maximilien; Baron, Stéphanie; Cornière, Nicolas; Alexander, R Todd; Hadchouel, Juliette; Eladari, Dominique; Hübner, Christian A; Chambrey, Régine

2017-01-01

We recently described a novel thiazide-sensitive electroneutral NaCl transport mechanism resulting from the parallel operation of the Cl - /HCO 3 - exchanger pendrin and the Na + -driven Cl - /2HCO 3 - exchanger (NDCBE) in β-intercalated cells of the collecting duct. Although a role for pendrin in maintaining Na + balance, intravascular volume, and BP is well supported, there is no in vivo evidence for the role of NDCBE in maintaining Na + balance. Here, we show that deletion of NDCBE in mice caused only subtle perturbations of Na + homeostasis and provide evidence that the Na + /Cl - cotransporter (NCC) compensated for the inactivation of NDCBE. To unmask the role of NDCBE, we generated Ndcbe/Ncc double-knockout (dKO) mice. On a normal salt diet, dKO and single-knockout mice exhibited similar activation of the renin-angiotensin-aldosterone system, whereas only dKO mice displayed a lower blood K + concentration. Furthermore, dKO mice displayed upregulation of the epithelial sodium channel (ENaC) and the Ca 2+ -activated K + channel BKCa. During NaCl depletion, only dKO mice developed marked intravascular volume contraction, despite dramatically increased renin activity. Notably, the increase in aldosterone levels expected on NaCl depletion was attenuated in dKO mice, and single-knockout and dKO mice had similar blood K + concentrations under this condition. In conclusion, NDCBE is necessary for maintaining sodium balance and intravascular volume during salt depletion or NCC inactivation in mice. Furthermore, NDCBE has an important role in the prevention of hypokalemia. Because NCC and NDCBE are both thiazide targets, the combined inhibition of NCC and the NDCBE/pendrin system may explain thiazide-induced hypokalemia in some patients. Copyright © 2016 by the American Society of Nephrology.
Tristan da Cunha Island

NASA Image and Video Library

2018-05-25

Tristan da Cunha is both a remote group of volcanic islands in the south Atlantic, and the main island. It is the most remote inhabited island group in the world, 2400 km from the nearest inhabited land. Tristan has a population of about 250 inhabitants, and is part of the British overseas territory of Saint Helena, Ascension and Tristan da Cunha. In 1961 the eruption of Queen Mary's Peak forced the evacuation of the entire population for two years. The image was acquired October 7, 2017, and is located at 37.1 degrees south, 12.3 degrees west. https://photojournal.jpl.nasa.gov/catalog/PIA22506
Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions.

PubMed

Wang, Yimin; Bowman, Joel M; Kamarchik, Eugene

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na(+)H2O, F(-)H2O, and Cl(-)H2O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H2O potentials are permutationally invariant fits to roughly 20,000 coupled cluster CCSD(T) energies (awCVTZ basis for Na(+) and aVTZ basis for Cl(-) and F(-)), over a large range of distances and H2O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.
Threshold oxygen levels in Na(I) for the formation of NaCrO 2(s) on 18-8 stainless steels from accurate thermodynamic measurements

NASA Astrophysics Data System (ADS)

Sreedharan, O. M.; Madan, B. S.; Gnanamoorthy, J. B.

1983-12-01

The compound NaCrO 2(s) is an important corrosion product in sodium-cooled LMFBRs. The standard Gibbs energy of formation of NaCrO 2(s) is required for the computation of threshold oxygen levels in Na(1) for the formation of NaCrO 2(s) on 18-8 stainless steels. For this purpose the emf of the galvanic cell: Pt, NaCrO 2, Cr 2O 3, Na 2CrO 4/15 YSZ/O 2 ( P O 2 = 0.21 atm, air), Pt was measured over 784-1012 K to be: (E±4.4)(mV) = 483.67-0.34155 T(K). From this, the standard Gibbs energy of formation of NaCrO 2(s) from the elements ( ΔG f,T0) and from the oxides ( ΔG f,OX,T0) was calculated to be: [ΔG f,T0(NaCrO 2, s)±1.86] (kJ/mol) =-869.98 + 0.18575 T(K) , [ΔG f,OX,T0(NaCr0 2, s)±4.8] (kJ/mol) = -104.25-0.00856 T(K) . The molar heat capacity, C P0, of NaCrO 2(s) was measured by DSC to be (350-600 K): C P0(NaCrO 2, s) (J/K mol) = 27.15 + 0.1247 T (K) , From these data, values of -99.3 kJ/mol and 91.6 J/K mol were computed for ΔH f,2980 and S 2980 of NaCrO 2(s). The internal consistency was checked with the use of enthalpy data on Na 2CrO 4(s). From the standard Gibbs energy of formation of NaCrO 2(s) the equation logC 0(wppm) = 3.9905-3147.6 T(K) was derived, where C 0 is the threshold oxygen level for the formation of NaCrO 2(s) on 18-8 stainless steels.
A Versatile Low Temperature Synthetic Route to Zintl Phase Precursors: Na4Si4, Na4Ge4 and K4Ge4 as Examples

PubMed Central

Ma, Xuchu; Xu, Fen; Atkins, Tonya; Goforth, Andrea M.; Neiner, Doinita; Navrotsky, Alexandra; Kauzlarich, Susan M.

2010-01-01

Na4Si4 and Na4Ge4 are ideal chemical precursors for inorganic clathrate structures, clusters, and nanocrystals. The monoclinic Zintl phases, Na4Si4 and Na4Ge4, contain isolated homo-tetrahedranide [Si4]4− and [Ge4]4− clusters surrounded by alkali metal cations. In this study, a simple scalable route has been applied to prepare Zintl phases of composition Na4Si4 and Na4Ge4 using the reaction between NaH and Si or Ge at low temperature (420 °C for Na4Si4 and 270 °C for Na4Ge4). The method was also applied to K4Ge4, using KH and Ge as raw materials, to show the versatility of this approach. The influence of specific reaction conditions on the purity of these Zintl phases has been studied by controlling five factors: the method of reagent mixing (manual or ball milled), the stoichiometry between raw materials, the reaction temperature, the heating time and the gas flow rate. Moderate ball-milling and excess NaH or KH facilitate the formation of pure Na4Si4, Na4Ge4 or K4Ge4 at 420 °C (Na4Si4) or 270 °C (both M4Ge4 compounds, M = Na, K). TG/DSC analysis of the reaction of NaH and Ge indicates that ball milling reduces the temperature for reaction and confirms the formation temperature. This method provides large quantities of high quality Na4Si4 and Na4Ge4 without the need for specialized laboratory equipment, such as Schlenk lines, niobium/tantalum containers, or an arc welder, thereby expanding the accessibility and chemical utility of these phases by making them more convenient to prepare. This new synthetic method may also be extended to lithium-containing Zintl phases (LiH is commercially available) as well as to alkali metal-tetrel Zintl compounds of other compositions, e.g. K4Ge9. PMID:19921060
WRS2 UPA DA Removal

NASA Image and Video Library

2009-11-23

ISS021-E-032275 (23 Nov. 2009) --- NASA astronaut Leland Melvin, STS-129 mission specialist, holds the failed Urine Processor Assembly / Distillation Assembly (UPA DA) in the Destiny laboratory of the International Space Station while space shuttle Atlantis remains docked with the station. Melvin and European Space Agency astronaut Frank De Winne (out of frame), Expedition 21 commander, removed and packed the UPA DA, then transferred it from the Water Recovery System 2 (WRS-2) rack to Atlantis for stowage on the middeck.
NPF MECHANICAL CELL NaK DISPOSAL AND FUME ABATEMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rey, G.

Some of the fuels originally scheduled for processing in the nonproduction fuel (NPF) processing program incorporated sodium or sodium- potassium alloy (NaK) as the bonding material between stainless-steel cladding and the uranium or uranium-molybdenum alloy core. Because of the special hazards involved in handling NaK, studies were made to determine safe methods for processing NaK-containing fuels. An underwater NaK dispensing system was installed, and tests were made to determine the characteristics of the NaK-water reaction. The equipment consisted of a dispenser, reaction pan, and off-gas scrubber. After initinl studies, a prototype test was made wherein U-Mo canned slugs containing NaKmore » reservoirs were hack sawed underwater. The studies demonstrated that the NaK reservoirs can be safely deactivated by hack sawing under a submerged hood in a shallow water bath. (W.L.H.)« less
Influence of exercise on NA- and Hsp72-induced release of IFNγ by the peritoneal suspension of macrophages and lymphocytes from genetically obese Zucker rats.

PubMed

Martín-Cordero, L; García, J J; Hinchado, M D; Bote, E; Ortega, E

2013-03-01

Regular physical exercise is recognized as a nonpharmacological therapeutic strategy in the treatment of metabolic syndrome, and has been proposed for improving obesity, diabetic status, insulin resistance, and immune response. The aim of the present study was to evaluate the effect of a regular exercise program (treadmill running, 5 days/week for 14 weeks at 35 cm/s for 35 min in the last month) on the release of the pro-inflammatory cytokine interferon gamma (IFNγ) by peritoneal cells (macrophages and lymphocytes) from obese Zucker rats (fa/fa) in response to noradrenaline (NA) and heat shock proteins of 72 kDa (Hsp72), and the possible adaptation due to training for a bout acute exercise (a single session of 25-35 min at 35 cm/s). In healthy (lean Fa/fa) and obese animals, peritoneal cells released greater concentrations of IFNγ in response to Hsp72 and lower concentrations in response to NA. The regular exercise training protocol, evaluated in the obese animals, produced a clear change in the regulation of the release of IFNγ. Peritoneal immune cells from trained animals released more IFNγ in response to NA, but there was a reduction in the release of IFNγ in response to Hsp72. In the obese animals, regular exercise caused a change in the inhibitory effect of NA (which now becomes stimulatory) and the stimulatory effect of Hsp72e (which now becomes inhibitory) in relation to the release of IFNγ. This reflects that Hsp72, induced by the prior release of NA following exercise-induced stress, plays a role in the homeostatic balance of release of IFNγ by peritoneal immune cells in obese animals during exercise.
pH-regulative synthesis of Na 3(VPO 4) 2F 3 nanoflowers and their improved Na cycling stability

DOE PAGES

Qi, Yuruo; Mu, Linqin; Zhao, Junmei; ...

2016-04-08

Na-ion batteries are becoming increasingly attractive as a low cost energy storage device. Sodium vanadium fluorophosphates have been studied extensively recently due to their high storage capacity and high discharge voltage. Shape and size often have a crucial influence over the properties. The controlling synthesis of nanoparticles with special microstructures is significant, which becomes a challenging issue and has drawn considerable attention. In this study, Na 3(VPO 4) 2F 3 nanoflowers have been synthesized via a pH-regulative low-temperature (120 °C) hydro-thermal route. In particular, it is a green route without any organic compounds involved. The hydro-thermal reaction time for themore » formation of Na 3(VPO 4) 2F 3 nanoflowers has also been investigated. A weak acid environment (pH = 2.60) with the possible presence of hydrogen fluoride molecules is necessary for the formation of the desired nanoflower microstructures. Moreover, compared to the nanoparticles obtained by Na 2HPO 4·12H 2O, the as-synthesized Na 3(VPO 4) 2F 3 nanoflowers showed an excellent Na-storage performance in terms of superior cycle stability, even without any further carbon coating or high-temperature treatment.« less
Cu(In,Ga)Se2 surface treatment with Na and NaF: A combined photoelectron spectroscopy and surface photovoltage study in ultra-high vacuum

NASA Astrophysics Data System (ADS)

Parvan, V.; Mizrak, A.; Majumdar, I.; Ümsür, B.; Calvet, W.; Greiner, D.; Kaufmann, C. A.; Dittrich, T.; Avancini, E.; Lauermann, I.

2018-06-01

Either metallic Na or NaF were deposited onto Cu(In,Ga)Se2 surfaces and studied by photoelectron spectroscopy and surface photovoltage spectroscopy without breaking the ultra-high vacuum. The deposition of elemental Na at room temperature led to the formation of an intermediate Cu and Ga rich layer at the CIGSe surface, whereas for NaF the composition of the CIGSe surface remained unchanged. A metal like surface induced by an inverted near surface region with a reduced number of defect states was formed after the deposition of Na. Under the chosen experimental conditions, the near surface layer was independent on the amount of Na and stable in time. In contrast, the usage of NaF weakened the inversion and led to an increased band bending compared to the untreated CIGSe sample. The SPV signals decreased with proceeding time after the deposition of NaF.
Identificação de variáveis cataclísmicas eruptivas na direção do bojo galáctico e Nuvens de Magalhães usando dados do OGLE

NASA Astrophysics Data System (ADS)

Cieslinski, D.; Diaz, M. P.; Mennickent, R.; Pietrzyski, G.

2003-08-01

Na década de 90 iniciaram-se vários programas para a pesquisa de matéria escura na Galáxia usando o efeito de microlentes gravitacionais. Entre os projetos mais bem conhecidos podemos mencionar o OGLE (Optical Gravitational Lensing Experiment) e o MACHO (MAssive Compact Halo Objects). A estratégia usada por eles consiste em fazer fotometria de banda larga (normalmente B, R e I) de um grande número de estrelas (dezenas de milhões) tão freqüentemente quanto possí vel e por longos perí odos de tempo (anos). Uma tal sistemática de observação, além de descobrir inúmeras lentes gravitacionais, é também muito apropriada para a descoberta de estrelas variáveis. De fato, inúmeras novas variáveis de vários tipos foram descobertas como subproduto. Exemplos podem ser encontrados nos endereços http://bulge.princeton.edu/~ogle/ e http://wwwmacho.mcmaster.ca/. As variáveis cataclí smicas eruptivas (novas clássicas, novas recorrentes e novas anãs) são objetos que apresentam variabilidade de grande amplitude com escalas de tempo de dias a centenas de dias e, por esta razão, devem ter sido detectadas em grande número nestes "surveys". Para testar esta possibilidade nós procuramos nos dados do OGLE por tais sistemas e o presente trabalho mostra os resultados desta pesquisa. Os objetos foram selecionados entre as variáveis detectadas usando a amplitude de variação de brilho como critério principal. Este critério forneceu 13756 objetos, sendo 2169 na direção da Grande Nuvem de Magalhães, 1162 na direção da Pequena Nuvem de Magalhães e o restante na direção do Bojo Galáctico. A análise foi feita inspecionando-se visualmente cada curva de luz por erupções com as características acima mencionadas. Os resultados obtidos podem ser sumarizados como: descoberta de duas novas clássicas e 33 novas anãs. Além disso, pode-se mencionar a identificação de candidatas a outros tipos de variáveis como: estrelas simbióticas, RV Tauri, R Coronae

Effects of Na2MoO4 and Na2WO4 on molybdenum and tungsten electrodes for the alkali metal thermoelectric converter (AMTEC)

NASA Technical Reports Server (NTRS)

Williams, R. M.; Wheeler, B. L.; Jeffries-Nakamura, B.; Loveland, M. E.; Bankston, C. P.

1988-01-01

The effects of adding Na2MoO4 and Na2WO4 to porous Mo and W electrodes, respectively, on the performance and impedance characteristics of the electrodes in an alkali metal thermoelectric converter (AMTEC) were investigated. It was found that corrosion of the porous electrode by Na2MoO4 or Na2WO4 to form Na2MO3O6 and WO2, respectively, and recrystallization of the Mo or W as the salt evaporates, result in major morphological changes including a loss of columnar structure and a significant increase in porosity. This effect is more pronounced in Na2MoO4/Mo electrodes, due to the lower stability of Na2MoO4.
Functional identification and characterization of sodium binding sites in Na symporters

PubMed Central

Loo, Donald D. F.; Jiang, Xuan; Gorraitz, Edurne; Hirayama, Bruce A.; Wright, Ernest M.

2013-01-01

Sodium cotransporters from several different gene families belong to the leucine transporter (LeuT) structural family. Although the identification of Na+ in binding sites is beyond the resolution of the structures, two Na+ binding sites (Na1 and Na2) have been proposed in LeuT. Na2 is conserved in the LeuT family but Na1 is not. A biophysical method has been used to measure sodium dissociation constants (Kd) of wild-type and mutant human sodium glucose cotransport (hSGLT1) proteins to identify the Na+ binding sites in hSGLT1. The Na1 site is formed by residues in the sugar binding pocket, and their mutation influences sodium binding to Na1 but not to Na2. For the canonical Na2 site formed by two –OH side chains, S392 and S393, and three backbone carbonyls, mutation of S392 to cysteine increased the sodium Kd by sixfold. This was accompanied by a dramatic reduction in the apparent sugar and phlorizin affinities. We suggest that mutation of S392 in the Na2 site produces a structural rearrangement of the sugar binding pocket to disrupt both the binding of the second Na+ and the binding of sugar. In contrast, the S393 mutations produce no significant changes in sodium, sugar, and phlorizin affinities. We conclude that the Na2 site is conserved in hSGLT1, the side chain of S392 and the backbone carbonyl of S393 are important in the first Na+ binding, and that Na+ binding to Na2 promotes binding to Na1 and also sugar binding. PMID:24191006
Fabrication and Luminescence Characterization of a Silica Nanomatrix Embedded with NaYF4:Yb:Er:Tm@NaGdF4/Fe3O4 Nanoparticles

NASA Astrophysics Data System (ADS)

Thangaraju, Dheivasigamani; Santhana, Vedi; Matsuda, Satoshi; Hayakawa, Yasuhiro

2018-05-01

Hexagonal NaYF4:Yb:Er:Tm@NaGdF4 core-shell nanocrystals were synthesized using a seed mediated hot injection method, and monodispersed Fe3O4 (4 nm) nanoparticles were prepared from iron(II) actylacetonate by a precursor thermal decomposition method. Structural and morphology verified NaYF4:Yb:Er:Tm@NaGdF4 and Fe3O4 nanoparticles were utilized for the preparation of NaYF4:Yb:Er:Tm@NaGdF4/Fe3O4@SiO2 nanocomposite using a micro-emulsion method. Existence of Fe3O4 in NaYF4:Yb:Er:Tm@NaGdF4 in SiO2 nano-spheres were confirmed with transmission electron microscopy. Luminescence measurement revealed that NaYF4:Yb:Er:Tm@NaGdF4 exhibited strong emissions at green and red regions, in addition to a weak blue emission also observed under 980 nm excitation. Up-conversion emission of the nanoparticle-embedded silica nanocomposite showed that the up-conversion emission was not affected by Fe3O4 nanoparticles.
Possibility of the transformation of eEF-2 (100 kDa) to eEF-2 (65 kDa) in the peptide elongation process in vitro.

PubMed

Gajko, A; Sredzińska, K; Galasiński, W; Gindzieński, A

1999-02-16

Two active eEF-2 polypeptides of approximately 100 and 65 kDa were copurified from rat liver cells and separated. The fate of eEF-2 (100 kDa) during its binding to ribosomes and in the translocation step of the peptide elongation process was investigated. It was shown that eEF-2 (100 kDa) did not change its form during the process of binding to the ribosomes. In the postribosomal supernatant, obtained from the postincubation mixture of the elongation process, only eEF-2 (65 kDa) was found. These results suggest that the form of eEF-2 (100 kDa), when bound to the ribosome during the elongation process, is transformed to eEF-2 (65 kDa). Copyright 1999 Academic Press.
[Clinical application of Da Vinci surgical system in China].

PubMed

Jin, Zhenyu

2014-01-01

Da Vinci robotic surgical system leads the development of minimally invasive surgical techniques. By using Da Vinci surgical robot for minimally invasive surgery, it brings a lot of advantages to the surgeons. Since 2008, Da Vinci surgeries have been performed in 14 hospitals in domestic cities such as Beijing and Shanghai. Until the end of 2012, 3 551 cases of Da Vinci robotic surgery have been performed, covering various procedures of various surgical departments including the department of general surgery, urology, cardiovascular surgery, thoracic surgery, gynecology, and etc. Robotic surgical technique has made remarkable achievements.
Digging up food: excavation stone tool use by wild capuchin monkeys.

PubMed

Falótico, Tiago; Siqueira, José O; Ottoni, Eduardo B

2017-07-24

Capuchin monkeys at Serra da Capivara National Park (SCNP) usually forage on the ground for roots and fossorial arthropods, digging primarily with their hands but also using stone tools to loosen the soil and aid the digging process. Here we describe the stone tools used for digging by two groups of capuchins on SCNP. Both groups used tools while digging three main food resources: Thiloa glaucocarpa tubers, Ocotea sp roots, and trapdoor spiders. One explanation for the occurrence of tool use in primates is the "necessity hypothesis", which states that the main function of tool use is to obtain fallback food. We tested for this, but only found a positive correlation between plant food availability and the frequency of stone tools' use. Thus, our data do not support the fallback food hypothesis for the use of tools to access burrowed resources.
WRS2 UPA DA Removal

NASA Image and Video Library

2009-11-23

ISS021-E-032273 (23 Nov. 2009) --- European Space Agency astronaut Frank De Winne, Expedition 21 commander, holds the failed Urine Processor Assembly / Distillation Assembly (UPA DA) in the Destiny laboratory of the International Space Station while space shuttle Atlantis remains docked with the station. De Winne and NASA astronaut Leland Melvin (out of frame), STS-129 mission specialist, removed and packed the UPA DA, then transferred it from the Water Recovery System 2 (WRS-2) rack to Atlantis for stowage on the middeck.
Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yimin, E-mail: yimin.wang@emory.edu; Bowman, Joel M., E-mail: jmbowma@emory.edu; Kamarchik, Eugene, E-mail: eugene.kamarchik@gmail.com

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na{sup +}H{sub 2}O, F{sup −}H{sub 2}O, and Cl{sup −}H{sub 2}O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H{sub 2}O potentials are permutationally invariant fits to roughly 20 000more » coupled cluster CCSD(T) energies (awCVTZ basis for Na{sup +} and aVTZ basis for Cl{sup −} and F{sup −}), over a large range of distances and H{sub 2}O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.« less
Secretory NaCl and volume flow in renal tubules.

PubMed

Beyenbach, K W

1986-05-01

This review attempts to give a retrospective survey of the available evidence concerning the secretion of NaCl and fluid in renal tubules of the vertebrate kidney. In the absence of glomerular filtration, epithelial secretory mechanisms, which to this date have not been elucidated, are responsible for the renal excretion of NaCl and water in aglomerular fish. However, proximal tubules isolated from glomerular fish kidneys of the flounder, killifish, and the shark also have the capacity to secrete NaCl and fluid. In shark proximal tubules, fluid secretion appears to be driven via secondary active transport of Cl. In another marine vertebrate, the sea snake, secretion of Na (presumably NaCl) and fluid is observed in freshwater-adapted and water-loaded animals. Proximal tubules of mammals can be made to secrete NaCl in vitro together with secretion of aryl acids. An epithelial cell line derived from dog kidney exhibits secondary active secretion of Cl when stimulated with catecholamines. Tubular secretion of NaCl and fluid may serve a variety of renal functions, all of which are considered here. The occurrence of NaCl and fluid secretion in glomerular proximal tubules of teleosts, elasmobranchs, and reptiles and in mammalian renal tissue cultures suggests that the genetic potential for NaCl secretion is present in every vertebrate kidney.
[da Vinci surgical system].

PubMed

Watanabe, Gou; Ishikawa, Norihiro

2014-07-01

The da Vinci surgical system was developed by Intuitive Surgical Inc. in the United States as an endoscopic surgical device to assist remote control surgeries. In 1998, the Da Vinci system was first used for cardiothoracic procedures. Currently a combination of robot-assisted internal thoracic artery harvest together with coronary artery bypass grafting (CABG) through a mini-incision (ThoraCAB) or totally endoscopic procedures including anastomoses under robotic assistance (TECAB) are being conducted for the treatment of coronary artery diseases. With the recent advances in catheter interventions, hybrid procedures combining catheter intervention with ThoraCAB or TECAB are anticipated in the future.On the other hand, with the decrease in number of coronary artery bypass surgeries, the share of valvular surgeries is expected to increase in the future. Among them, mitral valvuloplasty for mitral regurgitation is anticipated to be conducted mainly by low-invasive procedures, represented by minimally invasive cardiac surgery( MICS) and robot-assisted surgery. Apart from the intrinsic good surgical view, robotic-assisted systems offer additional advantages of the availability of an amplified view and the easy to observe the mitral valve in the physiological position. Thus, robotic surgical surgeries that make complicated procedures easier are expected to accomplish further developments in the future. Furthermore, while the number of surgeries for atrial septal defects has decreased dramatically following the widespread use of Amplatzer septal occluder, robotic surgery may become a good indication for cases in which the Amplatzer device is not indicated. In Japan, clinical trial of the da Vinci robotic system for heart surgeries has been completed. Statutory approval of the da Vinci system for mitral regurgitation and atrial septal defects is anticipated in the next few years.
Low-temperature glasslike properties in (NaCl)1-x(NaCN)x

NASA Astrophysics Data System (ADS)

Watson, Susan K.; Pohl, R. O.

1995-04-01

Thermal conductivity, internal friction, transverse sound velocity (60 mK to 300 K), and specific-heat data (100 mK to 40 K) for (NaCl)1-x(NaCN)x (x=0, 0.025, 0.05, 0.1, 0.76, 1) show a progression from crystalline to glasslike behavior as the CN- concentration is increased from 0 to 76 %. The evolution of glasslike properties is compared to that in other crystals in which glasslike properties evolve with increasing disorder, e.g., (KBr)1-x(KCN)x and Ba1-xLaxF2-x. For (KBr)1-x(KCN)x, Sethna and Chow have shown that as the concentration of the almost freely rotating CN- ions is increased the average potential barrier for CN- reorientation also increases through elastic quadrupolar interactions. For x~0.5, only a small density of low-energy states is left, which equals that observed in structural glasses. In Ba1-xLaxF2-x, on the other hand, the crystal field for small doping x is so large that no atomic motion occurs at low temperatures. (NaCl)1-x(NaCN)x is shown to represent an intermediate case, in that the crystal field is non-negligible at small x, yet glasslike low-energy excitations indicative of very small potential barrier heights evolve with increasing x. It is argued that random internal strains cause a decrease of the barrier heights in these crystals, which lead to the low-energy excitations. It is proposed that random strains have a similar effect in other disordered crystals as in Ba1-xLaxF2-x, which for small x show no low-energy mobile states, yet which for large x become glasslike.
NADH:ubiquinone oxidoreductase from bovine heart mitochondria. cDNA sequences of the import precursors of the nuclear-encoded 39 kDa and 42 kDa subunits.

PubMed Central

Fearnley, I M; Finel, M; Skehel, J M; Walker, J E

1991-01-01

The 39 kDa and 42 kDa subunits of NADH:ubiquinone oxidoreductase from bovine heart mitochondria are nuclear-coded components of the hydrophobic protein fraction of the enzyme. Their amino acid sequences have been deduced from the sequences of overlapping cDNA clones. These clones were amplified from total bovine heart cDNA by means of the polymerase chain reaction, with the use of complex mixtures of oligonucleotide primers based upon fragments of protein sequence determined at the N-terminals of the proteins and at internal sites. The protein sequences of the 39 kDa and 42 kDa subunits are 345 and 320 amino acid residues long respectively, and their calculated molecular masses are 39,115 Da and 36,693 Da. Both proteins are predominantly hydrophilic, but each contains one or two hydrophobic segments that could possibly be folded into transmembrane alpha-helices. The bovine 39 kDa protein sequence is related to that of a 40 kDa subunit from complex I from Neurospora crassa mitochondria; otherwise, it is not related significantly to any known sequence, including redox proteins and two polypeptides involved in import of proteins into mitochondria, known as the mitochondrial processing peptidase and the processing-enhancing protein. Therefore the functions of the 39 kDa and 42 kDa subunits of complex I are unknown. The mitochondrial gene product, ND4, a hydrophobic component of complex I with an apparent molecular mass of about 39 kDa, has been identified in preparations of the enzyme. This subunit stains faintly with Coomassie Blue dye, and in many gel systems it is not resolved from the nuclearcoded 36 kDa subunit. Images Fig. 1. PMID:1832859
Heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(s)

NASA Technical Reports Server (NTRS)

Leu, Ming-Taun; Timonen, Raimo S.; Keyser, Leon F.; Yung, Yuk L.

1995-01-01

The heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(S) (eq 2) were investigated over the temperature range 223-296 K in a flow-tube reactor coupled to a quadrupole mass spectrometer. Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity. In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10(exp -8) - 2 x 10(exp -6) Torr were used. Granule sizes and surface roughness of the solid NaCl substrates were determined by using a scanning electron microscope. For dry NaCl substrates, decay rates of HNO3 were used to obtain gamma(1) = 0.013 +/- 0.004 (1sigma) at 296 K and > 0.008 at 223 K, respectively. The error quoted is the statistical error. After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2. HCl was found to be the sole gas-phase product of reaction 1. The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K. For reaction 2 using dry salts, gamma(2) was found to be less than 1.0 x 10(exp -4) at both 223 and 296 K. The gas-phase reaction product was identified as ClNO2 in previous studies using an infrared spectrometer. An enhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) yields 2HNO3(g). Our results are compared with previous literature values obtained using different experimental techniques and conditions. The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after the El Chichon volcanic eruption and for the chemistry of HCl and HNO3 in the marine troposphere are discussed.
Role of alkali carbonate and salt in topochemical synthesis of K1/2Na1/2NbO3 and NaNbO3 templates

NASA Astrophysics Data System (ADS)

Lee, Jae-Seok; Jeon, Jae-Ho; Choi, Si-Young

2013-11-01

Since the properties of lead-free piezoelectric materials have thus far failed to meet those of lead-based materials, either chemical doping or morphological texturing should be employed to improve the piezoelectric properties of lead-free piezoelectric ceramics. The goal of this study was to synthesize plate-like K1/2Na1/2NbO3 and NaNbO3 particles, which are the most favorable templates for morphological texturing of K1/2Na1/2NbO3 ceramics. To achieve this goal, Bi2.5Na3.5Nb5O18 precursors in a plate-like shape were first synthesized and subsequently converted into K1/2Na1/2NbO3 or NaNbO3 particles that retain the morphology of Bi2.5Na3.5Nb5O18. In this study, we found that sodium or potassium carbonate does not play a major role in converting the Bi2.5Na3.5Nb5O18 precursor to K1/2Na1/2NbO3 or NaNbO3, on the contrary to previous reports; however, the salt contributes to the conversion reaction. All synthesis processes have been performed via a molten salt method, and scanning electron microscopy, scanning probe microscopy, and inductively coupled plasma mass spectroscopy were used to characterize the synthesized K1/2Na1/2NbO3 or NaNbO3 templates.
The 29-kDa proteins phosphorylated ion thrombin-activated human platelets are forms of the estrogen receptor-related 27-kDa heat shock protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendelsohn, M.E.; Yan Zhu; O'Neill, S.

Thrombin plays a critical role in platelet activation, hemostasis, and thrombosis. Cellular activation by thrombin leads to the phosphorylation of multiple proteins, most of which are unidentified. The authors have characterized several 29-kDa proteins that are rapidly phosphorylated following exposure of intact human platelets to thrombin. A murine monoclonal antibody raised to an unidentified estrogen receptor-related 29-kDa protein selectively recognized these proteins as well as a more basic, unphosphorylated 27-kDa protein. Cellular activation by thrombin led to a marked shift in the proportion of protein from the 27-kDa unphosphorylated form to the 29-kDa phosphoprotein species. Using this antibody, they isolatedmore » and sequenced a human cDNA clone encoding a protein that was identical to the mammalian 27-kDa heat shock protein (HSP27), a protein of uncertain function that is known to be phosphorylated to several forms and to be transcriptionally induced by estrogen. The 29-kDa proteins were confirmed to be phosphorylated forms of HSP27 by immunoprecipitation studies. Thus, the estrogen receptor-related protein is HSP27, and the three major 20-kDa proteins phosphorylated in thrombin-activated platelets are forms of HSP27. These data suggest a role for HSP27 in the signal transduction events of platelet activation.« less
Natural variability in Drosophila larval and pupal NaCl tolerance.

PubMed

Riedl, Craig A L; Oster, Sara; Busto, Macarena; Mackay, Trudy F C; Sokolowski, Marla B

2016-05-01

The regulation of NaCl is essential for the maintenance of cellular tonicity and functionality, and excessive salt exposure has many adverse effects. The fruit fly, Drosophila melanogaster, is a good osmoregulator and some strains can survive on media with very low or high NaCl content. Previous analyses of mutant alleles have implicated various stress signaling cascades in NaCl sensitivity or tolerance; however, the genes influencing natural variability of NaCl tolerance remain for the most part unknown. Here, we use two approaches to investigate natural variation in D. melanogaster NaCl tolerance. We describe four D. melanogaster lines that were selected for different degrees of NaCl tolerance, and present data on their survival, development, and pupation position when raised on varying NaCl concentrations. After finding evidence for natural variation in salt tolerance, we present the results of Quantitative Trait Loci (QTL) mapping of natural variation in larval and pupal NaCl tolerance, and identify different genomic regions associated with NaCl tolerance during larval and pupal development. Copyright © 2016 Elsevier Ltd. All rights reserved.
A Chimera Na+-Pump Rhodopsin as an Effective Optogenetic Silencer

PubMed Central

Hoque, Mohammad Razuanul; Ishizuka, Toru; Inoue, Keiichi; Abe-Yoshizumi, Rei; Igarashi, Hiroyuki; Mishima, Takaaki; Kandori, Hideki

2016-01-01

With the progress of optogenetics, the activities of genetically identified neurons can be optically silenced to determine whether the neurons in question are necessary for the network performance of the behavioral expression. This logical induction is expected to be improved by the application of the Na+ pump rhodopsins (NaRs), which hyperpolarize the membrane potential with negligible influence on the ionic/pH balance. Here, we made several chimeric NaRs between two NaRs, KR2 and IaNaR from Krokinobacter eikastus and Indibacter alkaliphilus, respectively. We found that one of these chimeras, named I1K6NaR, exhibited some improvements in the membrane targeting and photocurrent properties over native NaRs. The I1K6NaR-expressing cortical neurons were stably silenced by green light irradiation for a certain long duration. With its rapid kinetics and voltage dependency, the photoactivation of I1K6NaR would specifically counteract the generation of action potentials with less hyperpolarization of the neuronal membrane potential than KR2. PMID:27861619
Co-intercalation of Mg(2+) and Na(+) in Na(0.69)Fe2(CN)6 as a High-Voltage Cathode for Magnesium Batteries.

PubMed

Kim, Dong-Min; Kim, Youngjin; Arumugam, Durairaj; Woo, Sang Won; Jo, Yong Nam; Park, Min-Sik; Kim, Young-Jun; Choi, Nam-Soon; Lee, Kyu Tae

2016-04-06

Thanks to the advantages of low cost and good safety, magnesium metal batteries get the limelight as substituent for lithium ion batteries. However, the energy density of state-of-the-art magnesium batteries is not high enough because of their low operating potential; thus, it is necessary to improve the energy density by developing new high-voltage cathode materials. In this study, nanosized Berlin green Fe2(CN)6 and Prussian blue Na(0.69)Fe2(CN)6 are compared as high-voltage cathode materials for magnesium batteries. Interestingly, while Mg(2+) ions cannot be intercalated in Fe2(CN)6, Na(0.69)Fe2(CN)6 shows reversible intercalation and deintercalation of Mg(2+) ions, although they have the same crystal structure except for the presence of Na(+) ions. This phenomenon is attributed to the fact that Mg(2+) ions are more stable in Na(+)-containing Na(0.69)Fe2(CN)6 than in Na(+)-free Fe2(CN)6, indicating Na(+) ions in Na(0.69)Fe2(CN)6 plays a crucial role in stabilizing Mg(2+) ions. Na(0.69)Fe2(CN)6 delivers reversible capacity of approximately 70 mA h g(-1) at 3.0 V vs Mg/Mg(2+) and shows stable cycle performance over 35 cycles. Therefore, Prussian blue analogues are promising structures for high-voltage cathode materials in Mg batteries. Furthermore, this co-intercalation effect suggests new avenues for the development of cathode materials in hybrid magnesium batteries that use both Mg(2+) and Na(+) ions as charge carriers.
Crystallization kinetics from mixture Na2SO4/glycerol droplets of Na2SO4 by FTIR-ATR

NASA Astrophysics Data System (ADS)

Tan, Dan-Ting; Cai, Chen; Zhang, Yun; Wang, Na; Pang, Shu-Feng; Zhang, Yun-Hong

2016-08-01

The efflorescence of mixed Na2SO4/glycerol aerosols on the ZnSe substrate with various mole ratios (Na2SO4/glycerol = 1:1, 1:2, 1:4) has been studied in the relative humidity (RH) linearly decline process, using a situ Fourier transform infrared attenuated total reflection (FTIR-ATR) technique. The crystal ratio at a given RH can be gained by the absorbance of the band at 1132 cm-1, which shows the incomplete nucleation for mixed Na2SO4/glycerol aerosols and the decreased amount of the droplets crystallized at the lowest RH with the glycerol increase. Using the volume fraction of droplets that have yet to crystallize, the heterogeneous nucleation kinetics has been gained. By the Extended Aerosol Inorganics Model (E-AIM), the nucleation rate as the function of solute saturation degree has been gained for various mixed Na2SO4/glycerol aerosols.
Experimental study of the astrophysically important Na 23 ( α , p ) Mg 26 and Na 23 ( α , n ) Al 26 reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.

The 23Na(α,p) 26Mg and 23Na(α,n) 26Al reactions are important for our understanding of the 26Al abundance in massive stars. The aim of this work is to report on a direct and simultaneous measurement of these astrophysically important reactions using an active target system. The reactions were investigated in inverse kinematics using 4He as the active target gas in the detector. We measured the excitation functions in the energy range of about 2 to 6 MeV in the center of mass. We have found that the cross sections of the 23Na(α,p) 26Mg and the 23Na(α,n) 26Al reactions are in good agreementmore » with previous experiments and with statistical-model calculations. As a result, the astrophysical reaction rate of the 23Na(α,n) 26Al reaction has been reevaluated and it was found to be larger than the recommended rate.« less

Experimental study of the astrophysically important Na 23 ( α , p ) Mg 26 and Na 23 ( α , n ) Al 26 reactions

DOE PAGES

Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; ...

2016-12-19

The 23Na(α,p) 26Mg and 23Na(α,n) 26Al reactions are important for our understanding of the 26Al abundance in massive stars. The aim of this work is to report on a direct and simultaneous measurement of these astrophysically important reactions using an active target system. The reactions were investigated in inverse kinematics using 4He as the active target gas in the detector. We measured the excitation functions in the energy range of about 2 to 6 MeV in the center of mass. We have found that the cross sections of the 23Na(α,p) 26Mg and the 23Na(α,n) 26Al reactions are in good agreementmore » with previous experiments and with statistical-model calculations. As a result, the astrophysical reaction rate of the 23Na(α,n) 26Al reaction has been reevaluated and it was found to be larger than the recommended rate.« less
Double Knockout of the Na+-Driven Cl−/HCO3− Exchanger and Na+/Cl− Cotransporter Induces Hypokalemia and Volume Depletion

PubMed Central

Sinning, Anne; Radionov, Nikita; Trepiccione, Francesco; López-Cayuqueo, Karen I.; Jayat, Maximilien; Baron, Stéphanie; Cornière, Nicolas; Alexander, R. Todd; Hadchouel, Juliette; Eladari, Dominique; Hübner, Christian A.

2017-01-01

We recently described a novel thiazide–sensitive electroneutral NaCl transport mechanism resulting from the parallel operation of the Cl−/HCO3− exchanger pendrin and the Na+–driven Cl−/2HCO3− exchanger (NDCBE) in β-intercalated cells of the collecting duct. Although a role for pendrin in maintaining Na+ balance, intravascular volume, and BP is well supported, there is no in vivo evidence for the role of NDCBE in maintaining Na+ balance. Here, we show that deletion of NDCBE in mice caused only subtle perturbations of Na+ homeostasis and provide evidence that the Na+/Cl− cotransporter (NCC) compensated for the inactivation of NDCBE. To unmask the role of NDCBE, we generated Ndcbe/Ncc double–knockout (dKO) mice. On a normal salt diet, dKO and single-knockout mice exhibited similar activation of the renin-angiotensin-aldosterone system, whereas only dKO mice displayed a lower blood K+ concentration. Furthermore, dKO mice displayed upregulation of the epithelial sodium channel (ENaC) and the Ca2+–activated K+ channel BKCa. During NaCl depletion, only dKO mice developed marked intravascular volume contraction, despite dramatically increased renin activity. Notably, the increase in aldosterone levels expected on NaCl depletion was attenuated in dKO mice, and single-knockout and dKO mice had similar blood K+ concentrations under this condition. In conclusion, NDCBE is necessary for maintaining sodium balance and intravascular volume during salt depletion or NCC inactivation in mice. Furthermore, NDCBE has an important role in the prevention of hypokalemia. Because NCC and NDCBE are both thiazide targets, the combined inhibition of NCC and the NDCBE/pendrin system may explain thiazide-induced hypokalemia in some patients. PMID:27151921
Oxidation of ethanol on NaX zeolite modified with transition metals

NASA Astrophysics Data System (ADS)

Mirzai, J. I.; Nadirov, P. A.; Velieva, A. D.; Muradkhanli, V. G.

2017-06-01

NaLaX, NaX + Co, and NaPdX catalysts are synthesized by modification of NaX zeolite with transition metals (La, Co, Pd). The activity of the prepared materials in catalytic ethanol oxidation is studied in the temperature range of 423-723 K. It is shown that NaPdX and NaX + Co accelerate the reactions of partial and complete oxidation of ethanol as the temperature rises. NaLaX accelerates both intramolecular and intermolecular dehydration of alcohol. It is shown that the NaPdX (1.0% Pd) sample has the highest activity in the complete oxidation of alcohol with the formation of CO2.
Characterization of ZnAl cast alloys with Na addition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gancarz, Tomasz, E-mail: t.gancarz@imim.pl; Cempura, Grzegorz; Skuza, Wojciech

2016-01-15

This study was aimed at evaluating the microstructural change and thermal, electrical and mechanical properties with the addition of Na to eutectic ZnAl alloys. Solders based on eutectic ZnAl containing 0.2 to 3.0 (wt.%) of Na were developed for high temperature solder. Differential scanning calorimetry (DSC) measurements were performed to determine the melting temperatures of the alloys. Thermal linear expansion and electrical resistivity measurements were performed over − 50 °C to 300 °C and 30 °C to 300 °C temperature ranges, respectively. The microstructure of the specimens was analyzed using scanning (SEM) and transmission electron microscopy (TEM) techniques. Chemical microanalysismore » was performed by energy-dispersive X-ray spectroscopy (EDS) on SEM and TEM. The precipitates of NaZn{sub 13} were confirmed by X-ray diffraction (XRD) measurements and selected area electron diffraction (SAED) techniques. The addition of Na to eutectic ZnAl alloy increased the electrical resistivity and reduced the coefficient of thermal expansion; however, the melting point did not change. The mechanical properties, strain and microhardness increased with Na content in alloys. - Highlights: • High temperature soldering materials of ZnAl with Na were designed and characterized. • Precipitates of NaZn{sub 13}were observed and confirmed using TEM and XRD. • Addition of Na to eutectic ZnAl cussed increased mechanical properties. • NaZn{sub 13} caused increased electrical resistivity and microhardness, and reduced the CTE.« less
DaCHS: Data Center Helper Suite

NASA Astrophysics Data System (ADS)

Demleitner, Markus

2018-04-01

DaCHS, the Data Center Helper Suite, is an integrated package for publishing astronomical data sets to the Virtual Observatory. Network-facing, it speaks the major VO protocols (SCS, SIAP, SSAP, TAP, Datalink, etc). Operator-facing, many input formats, including FITS/WCS, ASCII files, and VOTable, can be processed to publication-ready data. DaCHS puts particular emphasis on integrated metadata handling, which facilitates a tight integration with the VO's Registry
Measurements of the liquidus surface and solidus transitions of the NaCl-UCl3 and NaCl-UCl3-CeCl3 phase diagrams

NASA Astrophysics Data System (ADS)

Sooby, E. S.; Nelson, A. T.; White, J. T.; McIntyre, P. M.

2015-11-01

NaCl-UCl3-PuCl3 is proposed as the fuel salt for a number of molten salt reactor concepts. No experimental data exists for the ternary system, and limited data is available for the binary compositions of this salt system. Differential scanning calorimetry is used in this study to examine the liquidus surface and solidus transition of a surrogate fuel-salt (NaCl-UCl3-CeCl3) and to reinvestigate the NaCl-UCl3 eutectic phase diagram. The results of this study show good agreement with previously reported data for the pure salt compounds used (NaCl, UCl3, and CeCl3) as well as for the eutectic points for the NaCl-UCl3 and NaCl-CeCl3 binary systems. The NaCl-UCl3 liquidus surface produced in this study predicts a 30-40 °C increase on the NaCl-rich side of the binary phase diagram. The increase in liquidus temperature could prove significant to molten salt reactor modeling.
Gamma Radiation Dose Rate in Air due to Terrestrial Radionuclides in Southern Brazil: Synthesis by Geological Units and Lithotypes Covered by the Serra do Mar Sul Aero-Geophysical Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bastos, Rodrigo O.; Appoloni, Carlos R.; Pinese, Jose P. P.

2008-08-07

The absorbed dose rates in air due to terrestrial radionuclides were estimated from aerial gamma spectrometric data for an area of 48,600 km{sup 2} in Southern Brazil. The source data was the Serra do Mar Sul Aero-Geophysical Project back-calibrated in a cooperative work among the Geological Survey of Brazil, the Geological Survey of Canada, and Paterson, Grant and Watson Ltd. The concentrations of eU (ppm), eTh (ppm) and K (%) were converted to dose rates in air (nGy{center_dot}h{sup -1}) by accounting for the contribution of each element's concentration. Regional variation was interpreted according to lithotypes and a synthesis was performedmore » according to the basic geological units present in the area. Higher values of total dose were estimated for felsic igneous and metamorphic rocks, with average values varying up to 119{+-}24 nGy{center_dot}h{sup -1}, obtained by Anitapolis syenite body. Sedimentary, metasedimentary and metamafic rocks presented the lower dose levels, and some beach deposits reached the lowest average total dose, 18.5{+-}8.2 nGy{center_dot}h{sup -1}. Thorium gives the main average contribution in all geological units, the highest value being reached by the nebulitic gneisses of Atuba Complex, 71{+-}23 nGy{center_dot}h{sup -1}. Potassium presents the lowest average contribution to dose rate in 53 of the 72 units analyzed, the highest contribution being obtained by intrusive alkaline bodies (28{+-}12 nGy{center_dot}h{sup -1}). The general pattern of geographic dose distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.« less
Kinetin Reversal of NaCl Effects

PubMed Central

Katz, Adriana; Dehan, Klara; Itai, Chanan

1978-01-01

Leaf discs of Nicotiana rustica L. were floated on NaCl in the presence of kinetin or abscisic acid. On the 5th day 14CO2 fixation, [3H]leucine incorporation, stomatal conductance, and chlorophyll content were determined. Kinetin either partially or completely reversed the inhibitory effects of NaCl while ABA had no effect. PMID:16660618
An enhancement to the NA4 gear vibration diagnostic parameter

NASA Technical Reports Server (NTRS)

Decker, Harry J.; Handschuh, Robert F.; Zakrajsek, James J.

1994-01-01

A new vibration diagnostic parameter for health monitoring of gears, NA4*, is proposed and tested. A recently developed gear vibration diagnostic parameter NA4 outperformed other fault detection methods at indicating the start and initial progression of damage. However, in some cases, as the damage progressed, the sensitivity of the NA4 and FM4 parameters tended to decrease and no longer indicated damage. A new parameter, NA4* was developed by enhancing NA4 to improve the trending of the parameter. This allows for the indication of damage both at initiation and also as the damage progresses. The NA4* parameter was verified and compared to the NA4 and FM4 parameters using experimental data from single mesh spur and spiral bevel gear fatigue rigs. The primary failure mode for the test cases was naturally occurring tooth surface pitting. The NA4* parameter is shown to be a more robust indicator of damage.
Magnetism in Na-filled Fe-based skutterudites

DOE PAGES

Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; ...

2015-06-01

The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. We investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe 4Sb 12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for amore » material near an itinerant ferromagnetic quantum critical point. NaFe 4P 12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe 4Sb 12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe 4As 12 shows intermediate behavior. We also present results for skutterudite FeSb 3, which is a metastable phase that has been reported in thin film form.« less
The effect of NaCl 0.9% and NaCl 0.45% on sodium, chloride, and acid-base balance in a PICU population.

PubMed

Almeida, Helena Isabel; Mascarenhas, Maria Inês; Loureiro, Helena Cristina; Abadesso, Clara S; Nunes, Pedro S; Moniz, Marta S; Machado, Maria Céu

2015-01-01

To study the effect of two intravenous maintenance fluids on plasma sodium (Na), and acid-base balance in pediatric intensive care patients during the first 24h of hospitalization. A prospective randomized controlled study was performed, which allocated 233 patients to groups: (A) NaCl 0.9% or (B) NaCl 0.45%. Patients were aged 1 day to 18 years, had normal electrolyte concentrations, and suffered an acute insult (medical/surgical). change in plasma sodium. Parametric tests: t-tests, ANOVA, X(2) statistical significance level was set at α=0.05. Group A (n=130): serum Na increased by 2.91 (±3.9)mmol/L at 24h (p<0.01); 2% patients had Na higher than 150 mmol/L. Mean urinary Na: 106.6 (±56.8)mmol/L. No change in pH at 0 and 24h. Group B (n=103): serum Na did not display statistically significant changes. Fifteen percent of the patients had Na<135 mmol/L at 24h. The two fluids had different effects on respiratory and post-operative situations. The use of saline 0.9% was associated with a lower incidence of electrolyte disturbances. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.
ATP Dependence of Na+/H+ Exchange

PubMed Central

Demaurex, Nicolas; Romanek, Robert R.; Orlowski, John; Grinstein, Sergio

1997-01-01

We studied the ATP dependence of NHE-1, the ubiquitous isoform of the Na+/H+ antiporter, using the whole-cell configuration of the patch-clamp technique to apply nucleotides intracellularly while measuring cytosolic pH (pHi) by microfluorimetry. Na+/H+ exchange activity was measured as the Na+-driven pHi recovery from an acid load, which was imposed via the patch pipette. In Chinese hamster ovary (CHO) fibroblasts stably transfected with NHE-1, omission of ATP from the pipette solution inhibited Na+/H+ exchange. Conversely, ATP perfusion restored exchange activity in cells that had been metabolically depleted by 2-deoxy-d-glucose and oligomycin. In cells dialyzed in the presence of ATP, no “run-down” was observed even after extended periods, suggesting that the nucleotide is the only diffusible factor required for optimal NHE-1 activity. Half-maximal activation of the antiporter was obtained at ∼5 mM Mg-ATP. Submillimolar concentrations failed to sustain Na+/H+ exchange even when an ATP regenerating system was included in the pipette solution. High ATP concentrations are also known to be required for the optimal function of other cation exchangers. In the case of the Na/Ca2+ exchanger, this requirement has been attributed to an aminophospholipid translocase, or “flippase.” The involvement of this enzyme in Na+/H+ exchange was examined using fluorescent phosphatidylserine, which is actively translocated by the flippase. ATP depletion decreased the transmembrane uptake of NBD-labeled phosphatidylserine (NBD-PS), indicating that the flippase was inhibited. Diamide, an agent reported to block the flippase, was as potent as ATP depletion in reducing NBD-PS uptake. However, diamide had no effect on Na+/H+ exchange, implying that the effect of ATP is not mediated by changes in lipid distribution across the plasma membrane. K-ATP and ATPγS were as efficient as Mg-ATP in sustaining NHE-1 activity, while AMP-PNP and AMP-PCP only partially substituted for ATP. In
Na+ Interactions with the Neutral Amino Acid Transporter ASCT1*

PubMed Central

Scopelliti, Amanda J.; Heinzelmann, Germano; Kuyucak, Serdar; Ryan, Renae M.; Vandenberg, Robert J.

2014-01-01

The alanine, serine, cysteine transporters (ASCTs) belong to the solute carrier family 1A (SLC1A), which also includes the excitatory amino acid transporters (EAATs) and the prokaryotic aspartate transporter GltPh. Acidic amino acid transport by the EAATs is coupled to the co-transport of three Na+ ions and one proton, and the counter-transport of one K+ ion. In contrast, neutral amino acid exchange by the ASCTs does not require protons or the counter-transport of K+ ions and the number of Na+ ions required is not well established. One property common to SLC1A family members is a substrate-activated anion conductance. We have investigated the number and location of Na+ ions required by ASCT1 by mutating residues in ASCT1 that correspond to residues in the EAATs and GltPh that are involved in Na+ binding. Mutations to all three proposed Na+ sites influence the binding of substrate and/or Na+, or the rate of substrate exchange. A G422S mutation near the Na2 site reduced Na+ affinity, without affecting the rate of exchange. D467T and D467A mutations in the Na1 site reduce Na+ and substrate affinity and also the rate of substrate exchange. T124A and D380A mutations in the Na3 site selectively reduce the affinity for Na+ and the rate of substrate exchange without affecting substrate affinity. In many of the mutants that reduce the rate of substrate transport the amplitudes of the substrate-activated anion conductances are not substantially affected indicating altered ion dependence for channel activation compared with substrate exchange. PMID:24808181
Neuronal Na+ Channels Are Integral Components of Pro-arrhythmic Na+/Ca2+ Signaling Nanodomain That Promotes Cardiac Arrhythmias During β-adrenergic Stimulation

PubMed Central

Radwański, Przemysław B.; Ho, Hsiang-Ting; Veeraraghavan, Rengasayee; Brunello, Lucia; Liu, Bin; Belevych, Andriy E.; Unudurthi, Sathya D.; Makara, Michael A.; Priori, Silvia G.; Volpe, Pompeo; Armoundas, Antonis A.; Dillmann, Wolfgang H.; Knollmann, Bjorn C.; Mohler, Peter J.; Hund, Thomas J.; Györke, Sándor

2016-01-01

Background Cardiac arrhythmias are a leading cause of death in the US. Vast majority of these arrhythmias including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with increased levels of circulating catecholamines and involve abnormal impulse formation secondary to aberrant Ca2+ and Na+ handling. However, the mechanistic link between β-AR stimulation and the subcellular/molecular arrhythmogenic trigger(s) remains elusive. Methods and Results We performed functional and structural studies to assess Ca2+ and Na+ signaling in ventricular myocyte as well as surface electrocardiograms in mouse models of cardiac calsequestrin (CASQ2)-associated CPVT. We demonstrate that a subpopulation of Na+ channels (neuronal Na+ channels; nNav) that colocalize with RyR2 and Na+/Ca2+ exchanger (NCX) are a part of the β-AR-mediated arrhythmogenic process. Specifically, augmented Na+ entry via nNav in the settings of genetic defects within the RyR2 complex and enhanced sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA)-mediated SR Ca2+ refill is both an essential and a necessary factor for the arrhythmogenesis. Furthermore, we show that augmentation of Na+ entry involves β-AR-mediated activation of CAMKII subsequently leading to nNav augmentation. Importantly, selective pharmacological inhibition as well as silencing of Nav1.6 inhibit myocyte arrhythmic potential and prevent arrhythmias in vivo. Conclusion These data suggest that the arrhythmogenic alteration in Na+/Ca2+ handling evidenced ruing β-AR stimulation results, at least in part, from enhanced Na+ influx through nNav. Therefore, selective inhibition of these channels and Nav1.6 in particular can serve as a potential antiarrhythmic therapy. PMID:27747307
Feasibility study for a secondary Na/S battery

NASA Technical Reports Server (NTRS)

Abraham, K. M.; Schiff, R.; Brummer, S. B.

1979-01-01

The feasibility of a moderate temperature Na battery was studied. This battery is to operate at a temperature in the range of 100-150 C. Two kinds of cathode were investigated: (1) a soluble S cathode consisting of a solution of Na2Sn in an organic solvent and (2) an insoluble S cathode consisting of a transition metal dichalcogenide in contact with a Na(+)ion conducting electrolyte. Four amide solvents, dimethyl acetamide, diethyl acetamide, N-methyl acetamide and acetamide, were investigated as possible solvents for the soluble S cathode. Results of stability and electrochemical studies using these solvents are presented. The dialkyl substituted amides were found to be superior. Although the alcohol 1,3-cyclohexanediol was found to be stable in the presence of Na2Sn at 130 C, its Na2Sn solutions did not appear to have suitable electrochemical properties.
PCA as a practical indicator of OPLS-DA model reliability.

PubMed

Worley, Bradley; Powers, Robert

Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) are powerful statistical modeling tools that provide insights into separations between experimental groups based on high-dimensional spectral measurements from NMR, MS or other analytical instrumentation. However, when used without validation, these tools may lead investigators to statistically unreliable conclusions. This danger is especially real for Partial Least Squares (PLS) and OPLS, which aggressively force separations between experimental groups. As a result, OPLS-DA is often used as an alternative method when PCA fails to expose group separation, but this practice is highly dangerous. Without rigorous validation, OPLS-DA can easily yield statistically unreliable group separation. A Monte Carlo analysis of PCA group separations and OPLS-DA cross-validation metrics was performed on NMR datasets with statistically significant separations in scores-space. A linearly increasing amount of Gaussian noise was added to each data matrix followed by the construction and validation of PCA and OPLS-DA models. With increasing added noise, the PCA scores-space distance between groups rapidly decreased and the OPLS-DA cross-validation statistics simultaneously deteriorated. A decrease in correlation between the estimated loadings (added noise) and the true (original) loadings was also observed. While the validity of the OPLS-DA model diminished with increasing added noise, the group separation in scores-space remained basically unaffected. Supported by the results of Monte Carlo analyses of PCA group separations and OPLS-DA cross-validation metrics, we provide practical guidelines and cross-validatory recommendations for reliable inference from PCA and OPLS-DA models.
Mechanistic origin of low polarization in aprotic Na-O2 batteries.

PubMed

Ma, Shunchao; McKee, William C; Wang, Jiawei; Guo, Limin; Jansen, Martin; Xu, Ye; Peng, Zhangquan

2017-05-21

Research interest in aprotic sodium-air (Na-O 2 ) batteries is growing because of their considerably high theoretical specific energy and potentially better reversibility than lithium-air (Li-O 2 ) batteries. While Li 2 O 2 has been unequivocally identified as the major discharge product in Li-O 2 batteries containing relatively stable electrolytes, a multitude of discharge products, including NaO 2 , Na 2 O 2 and Na 2 O 2 ·2H 2 O, have been reported for Na-O 2 batteries and the corresponding cathodic electrochemistry remains incompletely understood. Herein, we provide molecular-level insights into the key mechanistic differences between Na-O 2 and Li-O 2 batteries based on gold electrodes in strictly dry, aprotic dimethyl sulfoxide electrolytes through a combination of in situ spectroelectrochemistry and density functional theory based modeling. While like Li-O 2 batteries, the formation of oxygen reduction products (i.e., O 2 - , NaO 2 and Na 2 O 2 ) in Na-O 2 batteries depends critically on the electrode potential, two factors lead to a better reversibility of Na-O 2 electrochemistry, and are therefore highly beneficial to a viable rechargeable metal-air battery design: (i) only O 2 - and NaO 2 , and no Na 2 O 2 , form down to as low as ∼1.5 V vs. Na/Na + during discharge; (ii) solid NaO 2 is quite soluble and its formation and oxidation can proceed through micro-reversible EC (a chemical reaction of the product after the electron transfer) and CE (a chemical reaction preceding the electron transfer) processes, respectively, with O 2 - as the key intermediate.
Mutations in the Na+/Citrate Cotransporter NaCT (SLC13A5) in Pediatric Patients with Epilepsy and Developmental Delay

PubMed Central

Klotz, Jenna; Porter, Brenda E; Colas, Claire; Schlessinger, Avner; Pajor, Ana M

2016-01-01

Mutations in the SLC13A5 gene that codes for the Na+/citrate cotransporter, NaCT, are associated with early onset epilepsy, developmental delay and tooth dysplasia in children. In this study, we identify additional SLC13A5 mutations in nine epilepsy patients from six families. To better characterize the syndrome, families with affected children answered questions about the scope of illness and the treatment strategies. Currently, there are no effective treatments, but some antiepileptic drugs targeting the γ-aminobutyric acid system reduce seizure frequency. Acetazolamide, a carbonic anhydrase inhibitor and atypical antiseizure medication, decreases seizures in four patients. In contrast to previous reports, the ketogenic diet and fasting resulted in worsening of symptoms. The effects of the mutations on NaCT transport function and protein expression were examined by transient transfections of COS-7 cells. There was no transport activity from any of the mutant transporters, although some of the mutant transporter proteins were present on the plasma membrane. The structural model of NaCT suggests that these mutations can affect helix packing or substrate binding. We tested various treatments, including chemical chaperones and low temperatures, but none improved transport function in the NaCT mutants. Interestingly, coexpression of NaCT and the mutants results in decreased protein expression and activity of the wild-type transporter, indicating functional interaction. In conclusion, this study has identified additional SLC13A5 mutations in patients with chronic epilepsy starting in the neonatal period, with the mutations producing inactive Na+/citrate transporters. PMID:27261973
DA-6034 Induces [Ca(2+)]i Increase in Epithelial Cells.

PubMed

Yang, Yu-Mi; Park, Soonhong; Ji, Hyewon; Kim, Tae-Im; Kim, Eung Kweon; Kang, Kyung Koo; Shin, Dong Min

2014-04-01

DA-6034, a eupatilin derivative of flavonoid, has shown potent effects on the protection of gastric mucosa and induced the increases in fluid and glycoprotein secretion in human and rat corneal and conjunctival cells, suggesting that it might be considered as a drug for the treatment of dry eye. However, whether DA-6034 induces Ca(2+) signaling and its underlying mechanism in epithelial cells are not known. In the present study, we investigated the mechanism for actions of DA-6034 in Ca(2+) signaling pathways of the epithelial cells (conjunctival and corneal cells) from human donor eyes and mouse salivary gland epithelial cells. DA-6034 activated Ca(2+)-activated Cl(-) channels (CaCCs) and increased intracellular calcium concentrations ([Ca(2+)]i) in primary cultured human conjunctival cells. DA-6034 also increased [Ca(2+)]i in mouse salivary gland cells and human corneal epithelial cells. [Ca(2+)]i increase of DA-6034 was dependent on the Ca(2+) entry from extracellular and Ca(2+) release from internal Ca(2+) stores. Interestingly, these effects of DA-6034 were related to ryanodine receptors (RyRs) but not phospholipase C/inositol 1,4,5-triphosphate (IP3) pathway and lysosomal Ca(2+) stores. These results suggest that DA-6034 induces Ca(2+) signaling via extracellular Ca(2+) entry and RyRs-sensitive Ca(2+) release from internal Ca(2+) stores in epithelial cells.
Study of HMG-CoA Reductase Inhibition Activity of the Hydrolyzed Product of Snakehead Fish (Channa striata) Skin Collagen with 50 kDa Collagenase from Bacillus licheniformis F11.4

PubMed Central

Virginia, Agnes; Rachmawati, Heni; Riani, Catur; Retnoningrum, Debbie S.

2016-01-01

Bioactive peptides produced from enzymatic hydrolysis fibrous protein have been proven to have several biological activities. Previous study showed that the hydrolysis product of snakehead fish skin collagen with 26 kDa collagenase from Bacillus licheniformis F11.4 showed HMG-CoA (HMGR) inhibition activity. The aim of this research was to determine the ability of the hydrolysis product produced from snakehead fish skin collagen hydrolysed by 50 kDa collagenase from B. licheniformis F11.4 in inhibiting HMGR activity. Snakehead fish skin collagen was extracted using an acid method and collagenase was produced from B. licheniformis F11.4 using half-strength Luria Bertani (LB) medium containing 5% collagen. Crude collagenase was concentrated and fractionated using the DEAE Sephadex A-25 column eluted with increasing gradient concentrations of NaCl. Collagen, collagenase, and fractions were analyzed using SDS-PAGE and collagenolytic activity was analyzed by the zymography method. Collagenase with 50 kDa molecular weight presented in fraction one was used to hydrolyze the collagen. The reaction was done in 18 hours at 50°C. The hydrolysis product using 3.51 μg collagen and 9 ng collagenase showed 25.8% inhibition activity against pravastatin. This work shows for the first time that the hydrolysis product of snakehead fish skin collagen and 50 kDa collagenase from B. licheniformis F11.4 has potential as an anticholesterol agent. PMID:27110500

Study of HMG-CoA Reductase Inhibition Activity of the Hydrolyzed Product of Snakehead Fish (Channa striata) Skin Collagen with 50 kDa Collagenase from Bacillus licheniformis F11.4.

PubMed

Virginia, Agnes; Rachmawati, Heni; Riani, Catur; Retnoningrum, Debbie S

2016-01-01

Bioactive peptides produced from enzymatic hydrolysis fibrous protein have been proven to have several biological activities. Previous study showed that the hydrolysis product of snakehead fish skin collagen with 26 kDa collagenase from Bacillus licheniformis F11.4 showed HMG-CoA (HMGR) inhibition activity. The aim of this research was to determine the ability of the hydrolysis product produced from snakehead fish skin collagen hydrolysed by 50 kDa collagenase from B. licheniformis F11.4 in inhibiting HMGR activity. Snakehead fish skin collagen was extracted using an acid method and collagenase was produced from B. licheniformis F11.4 using half-strength Luria Bertani (LB) medium containing 5% collagen. Crude collagenase was concentrated and fractionated using the DEAE Sephadex A-25 column eluted with increasing gradient concentrations of NaCl. Collagen, collagenase, and fractions were analyzed using SDS-PAGE and collagenolytic activity was analyzed by the zymography method. Collagenase with 50 kDa molecular weight presented in fraction one was used to hydrolyze the collagen. The reaction was done in 18 hours at 50°C. The hydrolysis product using 3.51 μg collagen and 9 ng collagenase showed 25.8% inhibition activity against pravastatin. This work shows for the first time that the hydrolysis product of snakehead fish skin collagen and 50 kDa collagenase from B. licheniformis F11.4 has potential as an anticholesterol agent.
Hydrogen Sulfide Induced Disruption of Na+ Homeostasis in the Cortex

PubMed Central

Chao, Dongman; He, Xiaozhou; Yang, Yilin; Balboni, Gianfranco; Salvadori, Severo; Kim, Dong H.; Xia, Ying

2012-01-01

Maintenance of ionic balance is essential for neuronal functioning. Hydrogen sulfide (H2S), a known toxic environmental gaseous pollutant, has been recently recognized as a gasotransmitter involved in numerous biological processes and is believed to play an important role in the neural activities under both physiological and pathological conditions. However, it is unclear if it plays any role in maintenance of ionic homeostasis in the brain under physiological/pathophysiological conditions. Here, we report by directly measuring Na+ activity using Na+ selective electrodes in mouse cortical slices that H2S donor sodium hydrosulfide (NaHS) increased Na+ influx in a concentration-dependent manner. This effect could be partially blocked by either Na+ channel blocker or N-methyl-D-aspartate receptor (NMDAR) blocker alone or almost completely abolished by coapplication of both blockers but not by non-NMDAR blocker. These data suggest that increased H2S in pathophysiological conditions, e.g., hypoxia/ischemia, potentially causes a disruption of ionic homeostasis by massive Na+ influx through Na+ channels and NMDARs, thus injuring neural functions. Activation of delta-opioid receptors (DOR), which reduces Na+ currents/influx in normoxia, had no effect on H2S-induced Na+ influx, suggesting that H2S-induced disruption of Na+ homeostasis is resistant to DOR regulation and may play a major role in neuronal injury in pathophysiological conditions, e.g., hypoxia/ischemia. PMID:22474073
Differential migratory properties of monocytes isolated from human subjects naïve and non-naïve to Cannabis

PubMed Central

Silvestroni, Aurelio; Möller, Thomas; Stella, Nephi

2015-01-01

This study evaluates the migratory potential of monocytes isolated from two groups of human subjects: naïve and non-naïve to Cannabis. Phytocannabinoids (pCB), the bioactive agents produced by the plant Cannabis, regulate the phenotype and function of immune cells by interacting with CB1 and CB2 receptors. It has been shown that agents influencing the phenotype of circulating monocytes influence the phenotype of macrophages and the outcome of immune responses. To date, nothing is known about the acute and long-term effects of pCB on human circulating monocytes. Healthy subjects were recruited for a single blood draw. Monocytes were isolated, fluorescently labeled and their migration quantified using a validated assay that employs near infrared fluorescence and modified Boyden chambers. CB1 and CB2 receptor mRNA expression was quantified by qPCR. Monocytes from all subjects (n = 10) responded to chemokine (c–c motif) ligand 2 (CCL2) and human serum stimuli. Acute application of pCB significantly inhibited both the basal and CCL2-stimulated migration of monocytes, but only in subjects non-naïve to Cannabis. qPCR analysis indicates that monocytes from subjects non-naïve to Cannabis express significantly more CB1 mRNA. The phenotype of monocytes isolated from subjects non-naïve to Cannabis is significantly different from monocytes isolated from subjects naïve to Cannabis. Only monocytes from subjects non-naïve to Cannabis respond to acute exposure to pCB by reducing their overall migratory capacity. Our study suggests that chronic exposure to Cannabis affects the phenotype of circulating monocytes and accordingly could influence outcome of inflammatory responses occurring in injured tissues. PMID:22492174
Differential migratory properties of monocytes isolated from human subjects naïve and non-naïve to Cannabis.

PubMed

Sexton, Michelle; Silvestroni, Aurelio; Möller, Thomas; Stella, Nephi

2013-06-01

This study evaluates the migratory potential of monocytes isolated from two groups of human subjects: naïve and non-naïve to Cannabis. Phytocannabinoids (pCB), the bioactive agents produced by the plant Cannabis, regulate the phenotype and function of immune cells by interacting with CB1 and CB2 receptors. It has been shown that agents influencing the phenotype of circulating monocytes influence the phenotype of macrophages and the outcome of immune responses. To date, nothing is known about the acute and long-term effects of pCB on human circulating monocytes. Healthy subjects were recruited for a single blood draw. Monocytes were isolated, fluorescently labeled and their migration quantified using a validated assay that employs near infrared fluorescence and modified Boyden chambers. CB1 and CB2 receptor mRNA expression was quantified by qPCR. Monocytes from all subjects (n = 10) responded to chemokine (c-c motif) ligand 2 (CCL2) and human serum stimuli. Acute application of pCB significantly inhibited both the basal and CCL2-stimulated migration of monocytes, but only in subjects non-naïve to Cannabis. qPCR analysis indicates that monocytes from subjects non-naïve to Cannabis express significantly more CB1 mRNA. The phenotype of monocytes isolated from subjects non-naïve to Cannabis is significantly different from monocytes isolated from subjects naïve to Cannabis. Only monocytes from subjects non-naïve to Cannabis respond to acute exposure to pCB by reducing their overall migratory capacity. Our study suggests that chronic exposure to Cannabis affects the phenotype of circulating monocytes and accordingly could influence outcome of inflammatory responses occurring in injured tissues.
Relationship between Na+-dependent respiration and Na+ + K+-adenosine triphosphatase activity in the action of thyroid hormone on rat jejunal mucosa.

PubMed Central

Liberman, U A; Asano, Y; Lo, C S; Edelman, I S

1979-01-01

Administration of three successive doses of triiodothyronine (T3) (50 micrograms/100 g body wt), given on alternate days to thyroidectomized and euthyroid rats, stimulated oxygen consumption (QO2) and Na+ transport-dependent respiration (QO2 [5]) in the stripped jejunal mucosa, a preparation that consisted mostly of epithelial cells. The increase in QO2(t) accounted for 57% of the increment in QO2 in the transition from the hypothyroid to the euthyroid state and for 29% of the increment in the transition from the euthyroid to the hyperthyroid state. Administration of T3 to hypothyroid rats also increased the yield of epithelial cells. Injection of T3 into thyroidectomized and euthyroid rats increased the specific activity (at Vmax) of the (Na+ + K+)-dependent adenosine triphosphatase (NaK-ATPase) in jejunal crude membrane preparations. No significant change was recorded in the activity of Mg-ATPase in the same preparation. The ratio of QO2/NaK-ATPase and QO2(t)/NaK-ATPase in the various thyroid states remained constant, indicating proportionate increased in the respiratory and enzymatic indices. The effect of administration of T3 to thyroidectomized rats on the number of NaK-ATPase units (recovered in the crude membrane preparation) was estimated by: (a) Na+ + Mg++ + ATP-dependent binding of [3H]-ouabain to crude membrane fractions, and (b) the amount of the phosphorylated intermediate formed in the NaK-ATPase reaction from AT32P(gamma). Estimates were obtained of the maximal number of [3H]ouabain binding sites (Nm) and dissociation constants (Kd). Nm for [3H]ouabain and Nak-ATPase specific activity increased to about the same extent after T3 administration to thyroidectomized rats, with no change in the apparent Kd values. The amount of phosphorylated intermediate formed in jejunal crude membrane preparations also increased significantly. Thus, thyroid hormone administration may increase the number of active Na+pump sites in the plasma membrane. The apparent
Relationship between Na+-dependent respiration and Na+ + K+-adenosine triphosphatase activity in the action of thyroid hormone on rat jejunal mucosa.

PubMed

Liberman, U A; Asano, Y; Lo, C S; Edelman, I S

1979-07-01

Administration of three successive doses of triiodothyronine (T3) (50 micrograms/100 g body wt), given on alternate days to thyroidectomized and euthyroid rats, stimulated oxygen consumption (QO2) and Na+ transport-dependent respiration (QO2 [5]) in the stripped jejunal mucosa, a preparation that consisted mostly of epithelial cells. The increase in QO2(t) accounted for 57% of the increment in QO2 in the transition from the hypothyroid to the euthyroid state and for 29% of the increment in the transition from the euthyroid to the hyperthyroid state. Administration of T3 to hypothyroid rats also increased the yield of epithelial cells. Injection of T3 into thyroidectomized and euthyroid rats increased the specific activity (at Vmax) of the (Na+ + K+)-dependent adenosine triphosphatase (NaK-ATPase) in jejunal crude membrane preparations. No significant change was recorded in the activity of Mg-ATPase in the same preparation. The ratio of QO2/NaK-ATPase and QO2(t)/NaK-ATPase in the various thyroid states remained constant, indicating proportionate increased in the respiratory and enzymatic indices. The effect of administration of T3 to thyroidectomized rats on the number of NaK-ATPase units (recovered in the crude membrane preparation) was estimated by: (a) Na+ + Mg++ + ATP-dependent binding of [3H]-ouabain to crude membrane fractions, and (b) the amount of the phosphorylated intermediate formed in the NaK-ATPase reaction from AT32P(gamma). Estimates were obtained of the maximal number of [3H]ouabain binding sites (Nm) and dissociation constants (Kd). Nm for [3H]ouabain and Nak-ATPase specific activity increased to about the same extent after T3 administration to thyroidectomized rats, with no change in the apparent Kd values. The amount of phosphorylated intermediate formed in jejunal crude membrane preparations also increased significantly. Thus, thyroid hormone administration may increase the number of active Na+pump sites in the plasma membrane. The apparent
Na+/H+ Exchange Activity in the Plasma Membrane of Arabidopsis1

PubMed Central

Qiu, Quan-Sheng; Barkla, Bronwyn J.; Vera-Estrella, Rosario; Zhu, Jian-Kang; Schumaker, Karen S.

2003-01-01

In plants, Na+/H+ exchangers in the plasma membrane are critical for growth in high levels of salt, removing toxic Na+ from the cytoplasm by transport out of the cell. The molecular identity of a plasma membrane Na+/H+ exchanger in Arabidopsis (SOS1) has recently been determined. In this study, immunological analysis provided evidence that SOS1 localizes to the plasma membrane of leaves and roots. To characterize the transport activity of this protein, purified plasma membrane vesicles were isolated from leaves of Arabidopsis. Na+/H+ exchange activity, monitored as the ability of Na to dissipate an established pH gradient, was absent in plants grown without salt. However, exchange activity was induced when plants were grown in 250 mm NaCl and increased with prolonged salt exposure up to 8 d. H+-coupled exchange was specific for Na, because chloride salts of other monovalent cations did not dissipate the pH gradient. Na+/H+ exchange activity was dependent on Na (substrate) concentration, and kinetic analysis indicated that the affinity (apparent Km) of the transporter for Na+ is 22.8 mm. Data from two experimental approaches supports electroneutral exchange (one Na+ exchanged for one proton): (a) no change in membrane potential was measured during the exchange reaction, and (b) Na+/H+ exchange was unaffected by the presence or absence of a membrane potential. Results from this research provide a framework for future studies into the regulation of the plant plasma membrane Na+/H+ exchanger and its relative contribution to the maintenance of cellular Na+ homeostasis during plant growth in salt. PMID:12805632
Electron scattering in graphene with adsorbed NaCl nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drabińska, Aneta, E-mail: Aneta.Drabinska@fuw.edu.pl; Kaźmierczak, Piotr; Bożek, Rafał

2015-01-07

In this work, the results of contactless magnetoconductance and Raman spectroscopy measurements performed for a graphene sample after its immersion in NaCl solution were presented. The properties of the immersed sample were compared with those of a non-immersed reference sample. Atomic force microscopy and electron spin resonance experiments confirmed the deposition of NaCl nanoparticles on the graphene surface. A weak localization signal observed using contactless magnetoconductance showed the reduction of the coherence length after NaCl treatment of graphene. Temperature dependence of the coherence length indicated a change from ballistic to diffusive regime in electron transport after NaCl treatment. The mainmore » inelastic scattering process was of the electron-electron type but the major reason for the reduction of the coherence length at low temperatures was additional, temperature independent, inelastic scattering. We associate it with spin flip scattering, caused by NaCl nanoparticles present on the graphene surface. Raman spectroscopy showed an increase in the D and D′ bands intensities for graphene after its immersion in NaCl solution. An analysis of the D, D′, and G bands intensities proved that this additional scattering is related to the decoration of vacancies and grain boundaries with NaCl nanoparticles, as well as generation of new on-site defects as a result of the decoration of the graphene surface with NaCl nanoparticles. The observed energy shifts of 2D and G bands indicated that NaCl deposition on the graphene surface did not change carrier concentration, but reduced compressive biaxial strain in the graphene layer.« less
Arrestins and Spinophilin Competitively Regulate Na+,K+-ATPase Trafficking through Association with a Large Cytoplasmic Loop of the Na+,K+-ATPase

PubMed Central

Kimura, Tohru; Allen, Patrick B.; Nairn, Angus C.

2007-01-01

The activity and trafficking of the Na+,K+-ATPase are regulated by several hormones, including dopamine, vasopressin, and adrenergic hormones through the action of G-protein–coupled receptors (GPCRs). Arrestins, GPCR kinases (GRKs), 14-3-3 proteins, and spinophilin interact with GPCRs and modulate the duration and magnitude of receptor signaling. We have found that arrestin 2 and 3, GRK 2 and 3, 14-3-3 ε, and spinophilin directly associate with the Na+,K+-ATPase and that the associations with arrestins, GRKs, or 14-3-3 ε are blocked in the presence of spinophilin. In COS cells that overexpressed arrestin, the Na+,K+-ATPase was redistributed to intracellular compartments. This effect was not seen in mock-transfected cells or in cells expressing spinophilin. Furthermore, expression of spinophilin appeared to slow, whereas overexpression of β-arrestins accelerated internalization of the Na+,K+-ATPase endocytosis. We also find that GRKs phosphorylate the Na+,K+-ATPase in vitro on its large cytoplasmic loop. Taken together, it appears that association with arrestins, GRKs, 14-3-3 ε, and spinophilin may be important modulators of Na+,K+-ATPase trafficking. PMID:17804821
32 CFR 516.25 - DA Form 4.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 3 2013-07-01 2013-07-01 false DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC... attached to a properly prepared and sealed DA Form 4 are self-authenticating. (See Fed. R. Evid. 902). (b...
32 CFR 516.25 - DA Form 4.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 3 2014-07-01 2014-07-01 false DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC... attached to a properly prepared and sealed DA Form 4 are self-authenticating. (See Fed. R. Evid. 902). (b...
32 CFR 516.25 - DA Form 4.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 3 2011-07-01 2009-07-01 true DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC RELATIONS... properly prepared and sealed DA Form 4 are self-authenticating. (See Fed. R. Evid. 902). (b) Preparation at...
32 CFR 516.25 - DA Form 4.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 3 2012-07-01 2009-07-01 true DA Form 4. 516.25 Section 516.25 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC RELATIONS... properly prepared and sealed DA Form 4 are self-authenticating. (See Fed. R. Evid. 902). (b) Preparation at...
Sodium ion transport mechanisms in antiperovskite electrolytes Na 3OBr and Na 4OI 2: An in Situ neutron diffraction study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jinlong; Wang, Yonggang; Li, Shuai

Na-rich antiperovskites are recently developed solid electrolytes with enhanced sodium ionic conductivity and show promising functionality as a novel solid electrolyte in an all solid-stat battery. In this work, the sodium ionic transport pathways of the parent compound Na 3OBr, as well as the modified layered antiperovskite Na 4OI 2, were studied and compared through temperature dependent neutron diffraction combined with the maximum entropy method. In the cubic Na 3OBr antiperovskite, the nuclear density distribution maps at 500 K indicate that sodium ions ho within and among oxygen octahedra, and Br - ions are not involved in the tetragonal Namore » 4OI 2 antiperovskite, Na ions, which connect octahedra in the ab plane, have the lowest activation energy barrier. In conclusion, the transport of sodium ions along the c axis is assisted by I - ions.« less
Sodium ion transport mechanisms in antiperovskite electrolytes Na 3OBr and Na 4OI 2: An in Situ neutron diffraction study

DOE PAGES

Zhu, Jinlong; Wang, Yonggang; Li, Shuai; ...

2016-06-02

Na-rich antiperovskites are recently developed solid electrolytes with enhanced sodium ionic conductivity and show promising functionality as a novel solid electrolyte in an all solid-stat battery. In this work, the sodium ionic transport pathways of the parent compound Na 3OBr, as well as the modified layered antiperovskite Na 4OI 2, were studied and compared through temperature dependent neutron diffraction combined with the maximum entropy method. In the cubic Na 3OBr antiperovskite, the nuclear density distribution maps at 500 K indicate that sodium ions ho within and among oxygen octahedra, and Br - ions are not involved in the tetragonal Namore » 4OI 2 antiperovskite, Na ions, which connect octahedra in the ab plane, have the lowest activation energy barrier. In conclusion, the transport of sodium ions along the c axis is assisted by I - ions.« less
DA1 receptors modulation in rat isolated trachea.

PubMed

Cabezas, Gloria A; Velasco, Manuel

2010-01-01

We have previously demonstrated that low dose of inhaled dopamine (0.5-2 microg kg(-1) min(-1)) induces broncodilatacion in patients with acute asthma attack, suggesting that this dopamine effect is mediated by dopaminergic rather than by adrenergic receptors. To understand better these dopamine effect, rat tracheal smooth muscle was used as a model to evaluate the responses of beta2-, alpha1-, alpha2-adrenergic and DA1 and DA2 dopaminergic antagonists. Tracheal rings from male Sprague-Dawley rats (n = 90) were excised and placed in an organ bath containing modified Krebs-Ringer bicarbonate buffer at 37 degrees C, and gassed with O2 (95%) and CO2 (5%). Contractile responses were recorded with an isometric transducer in a polygraph (Letica, Spain). Contraction was induced by accumulative doses of acetylcholine (0.1, 0.3, 1, 3, 10 mM) or by electric field stimulation (10 Hz at 2 milliseconds), and accumulative doses of dopamine were added to the bath. Low concentration (0.1-0.3 mM) elicited a small initial contraction, followed by a marked relaxation. Cholinergic contraction was completely reversed at 6 mM of dopamine. This biphasic dopaminergic response was not blocked by incubation with beta2-adrenergic antagonist propranolol (0.1 microM), alpha1-antagonist, terazosin (0.1 mM), alpha2-antagonist, yohimbine (0.1 mM), or by DA2 antagonist metoclopramide (1-8 mM); DA1 antagonist SCH23390 (0.1 microM) produced a sustained increase of basal tone but did not block initial dopaminergic contraction and partially inhibited bronchodilator effect of dopamine. Dopaminergic relaxation in rat trachea is mediated by DA1 rather than by DA2 receptors; and adrenergic receptors are not involved in such dopamine-induced response. Finally, DA1 antagonist SCH23390 exerts intrinsic contractile activity on airway smooth muscle that deserves further research.
Design and implementation of the NaI(Tl)/CsI(Na) detectors output signal generator

NASA Astrophysics Data System (ADS)

Zhou, Xu; Liu, Cong-Zhan; Zhao, Jian-Ling; Zhang, Fei; Zhang, Yi-Fei; Li, Zheng-Wei; Zhang, Shuo; Li, Xu-Fang; Lu, Xue-Feng; Xu, Zhen-Ling; Lu, Fang-Jun

2014-02-01

We designed and implemented a signal generator that can simulate the output of the NaI(Tl)/CsI(Na) detectors' pre-amplifier onboard the Hard X-ray Modulation Telescope (HXMT). Using the development of the FPGA (Field Programmable Gate Array) with VHDL language and adding a random constituent, we have finally produced the double exponential random pulse signal generator. The statistical distribution of the signal amplitude is programmable. The occurrence time intervals of the adjacent signals contain negative exponential distribution statistically.
The Douro estuarine plume: Detection, processes and dynamics =

NASA Astrophysics Data System (ADS)

Mendes, Renato Paulo dos Santos

O Douro e um dos maiores rios da Peninsula Iberica, constituindo a maior descarga de agua doce para o Oceano Atlântico na costa noroeste portuguesa. A sua pluma estuarina tem particular relevância na dinâmica costeira e na modulacao de fenomenos biogeoquimicos. Sao objetivos desta dissertacao contribuir para a compreensao dos processos fisicos associados a geracao e propagacao da pluma estuarina do Rio Douro no oceano, assim como para o conhecimento dos seus padroes de dispersao e da forma como estes alteram a hidrologia e a circulacao costeira, considerando os agentes forcadores tipicos deste fenomeno (caudal fluvial, vento e mare) e indices climaticos relevantes. Para concretizacao destes objetivos foram desenvolvidas e aplicadas metodologias inovadoras de processamento de dados de detecao remota, assim como novas implementacoes estuarinas e costeiras de modelos numericos. Atraves de imagens MODIS, otimizadas para o estudo de fenomenos costeiros, efetuou-se uma detecao rigorosa da pluma. Identificou-se uma relacao entre o sinal turbido nLw555 e o caudal, demonstrando-se este produto como um bom proxy para a observacao da pluma no oceano. As escalas temporais e espaciais da pluma foram caraterizadas atraves destas imagens, combinadas com dados de caudal fluvial, mare, vento e precipitacao, e tambem com indices climaticos relevantes. Para compreender a propagacao da pluma e caracterizar a sua dinâmica e impacto na circulacao costeira, foi desenvolvida uma aplicacao 3D de modelos estuarinos e costeiros com malhas aninhadas de resolucao variavel. Definiramse e analisaram-se diferentes cenarios de vento e descarga fluvial. A interacao da pluma do Rio Douro e do Minho foi ainda analisada atraves dos resultados de simulacoes baseadas num evento de inverno. Os compositos turbidos mostraram que a pluma e facilmente detetada quando o caudal e maior que 500 m3 s??1. A descarga fluvial e o vento sao os principais forcadores da sua propagacao, enquanto a mare e apenas
Enhancing Catalyzed Decomposition of Na2CO3 with Co2MnO x Nanowire-Decorated Carbon Fibers for Advanced Na-CO2 Batteries.

PubMed

Fang, Cong; Luo, Jianmin; Jin, Chengbin; Yuan, Huadong; Sheng, Ouwei; Huang, Hui; Gan, Yongping; Xia, Yang; Liang, Chu; Zhang, Jun; Zhang, Wenkui; Tao, Xinyong

2018-05-23

The metal-CO 2 batteries, especially Na-CO 2 , batteries come into sight owing to their high energy density, ability for CO 2 capture, and the abundance of sodium resource. Besides the sluggish electrochemical reactions at the gas cathodes and the instability of the electrolyte at a high voltage, the final discharge product Na 2 CO 3 is a solid and poor conductor of electricity, which may cause the high overpotential and poor cycle performance for the Na-CO 2 batteries. The promotion of decomposition of Na 2 CO 3 should be an efficient strategy to enhance the electrochemical performance. Here, we design a facile Na 2 CO 3 activation experiment to screen the efficient cathode catalyst for the Na-CO 2 batteries. It is found that the Co 2 MnO x nanowire-decorated carbon fibers (CMO@CF) can promote the Na 2 CO 3 decomposition at the lowest voltage among all these metal oxide-decorated carbon fiber structures. After assembling the Na-CO 2 batteries, the electrodes based on CMO@CF show lower overpotential and better cycling performance compared with the electrodes based on pristine carbon fibers and other metal oxide-modified carbon fibers. We believe this catalyst screening method and the freestanding structure of the CMO@CF electrode may provide an important reference for the development of advanced Na-CO 2 batteries.
NaCl intake and preference threshold of spontaneously hypertensive rats.

PubMed

Fregly, M J

1975-09-01

Both male and female spontaneously hypertensive (SH) rats have an appetite for NaCl solution. The appetite is present when a choice is offered between distilled water and either isotonic or hypertonic (0.25 M) NaCl solution to drink. Total fluid intake (water plus NaCl solution) was greater for SH rats than for controls while food intakes (g/100 g body wt/day) of SH rats were not different from controls. Mean body weight of SH rats was always less than that of controls. The appetite for NaCl solution was accompanied by a significant reduction in preference (detection) threshold. SH rats could detect the difference between distilled water and NaCl solution when the concentration of the latter was 12 mEq/liter compared to a control threshold of 30 mEq/liter. The NaCl appetite and reduced NaCl preference threshold induced by spontaneous hypertension is in marked contrast to the NaCl aversion induced by other types of experimentally induced hypertension in rats. The mechanism or mechanisms responsible for these differences remain for further study.

High-Pressure Polymorph of NaBiO3.

PubMed

Naa, Octavianti; Kumada, Nobuhiro; Miura, Akira; Takei, Takahiro; Azuma, Masaki; Kusano, Yoshihiro; Oka, Kengo

2016-06-20

A new high-pressure polymorph of NaBiO3 (hereafter β-NaBiO3) was synthesized under the conditions of 6 GPa and 600 °C. The powder X-ray diffraction pattern of this new phase was indexed with a hexagonal cell of a = 9.968(1) Å and c = 3.2933(4) Å. Crystal structure refinement using synchrotron powder X-ray diffraction data led to RWP = 8.53% and RP = 5.55%, and the crystal structure was closely related with that of Ba2SrY6O12. No photocatalytic activity for phenol decomposition was observed under visible-light irradiation in spite of a good performance for its mother compound, NaBiO3. The optical band-gap energy of β-NaBiO3 was narrower than that of NaBiO3, which was confirmed with density of states curves simulated by first-principles density functional theory calculation.
Na[superscript +] binding to meizothrombin desF1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papaconstantinou, M.E.; Gandhi, P.S.; Chen, Z.

2009-06-10

Meizothrombin is the physiologically active intermediate generated by a single cleavage of prothrombin at R320 to separate the A and B chains. Recent evidence has suggested that meizothrombin, like thrombin, is a Na{sup +}-activated enzyme. In this study we present the first X-ray crystal structure of human meizothrombin desF1 solved in the presence of the active site inhibitor PPACK at 2.1 {angstrom} resolution. The structure reveals a Na{sup +} binding site whose architecture is practically identical to that of human thrombin. Stopped-flow measurements of Na{sup +} binding to meizothrombin desF1 document a slow phase of fluorescence change with a kmore » obs decreasing hyperbolically with increasing [Na{sup +}], consistent with the existence of three conformations in equilibrium, E*, E and E:Na{sup +}, as for human thrombin. Evidence that meizothrombin exists in multiple conformations provides valuable new information for studies of the mechanism of prothrombin activation.« less
Caries-Preventive Effect of NaF, NaF plus TCP, NaF plus CPP-ACP, and SDF Varnishes on Sound Dentin and Artificial Dentin Caries in vitro.

PubMed

Wierichs, Richard J; Stausberg, Sabrina; Lausch, Julian; Meyer-Lueckel, Hendrik; Esteves-Oliveira, Marcella

2018-01-01

The aim of this study was to compare the caries-preventive effect of different fluoride varnishes on sound dentin as well as on artificial dentin caries-like lesions. Bovine dentin specimens (n = 220) with one sound surface (ST) and one artificial caries lesion (DT) were prepared and randomly allocated to 11 groups. The interventions before pH cycling were as follows: application of a varnish containing NaF (22,600 ppm F-; Duraphat [NaF0/NaF1]), NaF plus tricalcium phosphate (22,600 ppm F-; Clinpro White Varnish Mint [TCP0/TCP1]), NaF plus casein phosphopeptide-stabilized amorphous calcium phosphate complexes (CPP-ACP; 22,600 ppm F-; MI Varnish [CPP0/CPP1]), or silver diamine fluoride (SDF; 35,400 ppm F-; Cariestop 30% [SDF0/SDF1]) and no intervention (NNB/N0/N1). During pH cycling (14 days, 6 × 120 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 times/day) with either fluoride-free ("0"; e.g., TCP0) or 1,100 ppm F- ("1"; e.g., TCP1) dentifrice slurry. In another subgroup, the specimens were pH cycled but not brushed (NNB). Differences in integrated mineral loss (ΔΔZ), lesion depth (ΔLD), and colorimetric values (ΔΔE) were calculated between the values after initial demineralization and those after pH cycling, using transversal microradiography and photographic images. After pH cycling, no discoloration could be observed. Furthermore, NNB, N0, and N1 showed significantly increased ΔZDT/LDDT and ΔZST/LDST values, indicating further demineralization. In contrast, CPP0, CPP1, SDF0, and SDF1 showed significantly decreased ΔZDT/LDDT values, indicating remineralization (p ≤ 0.004; paired t test). CPP0, CPP1, SDF0, and SDF1 showed significantly higher changes in ΔΔZDT/ΔLDDT and ΔΔZST/ΔLDST than NNB, N0, and N1 (p < 0.001; Bonferroni post hoc test). In conclusion, under the conditions chosen, all fluoride varnishes prevented further demineralization. However, only NaF plus CPP-ACP and SDF could remineralize artificial
An empirical NaKCa geothermometer for natural waters

USGS Publications Warehouse

Fournier, R.O.; Truesdell, A.H.

1973-01-01

An empirical method of estimating the last temperature of water-rock interaction has been devised. It is based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340??C. The data for most geothermal waters cluster near a straight line when plotted as the function log ( Na K) + ?? log [ ??? (Ca) Na] vs reciprocal of absolute temperature, where ?? is either 1 3 or 4 3 depending upon whether the water equilibrated above or below 100??C. For most waters tested, the method gives better results than the Na K methods suggested by other workers. The ratio Na K should not be used to estimate temperature if ??? ( MCa) MNa is greater than 1. The Na K values of such waters generally yield calculated temperatures much higher than the actual temperature at which water interacted with the rock. A comparison of the composition of boiling hot-spring water with that obtained from a nearby well (170??C) in Yellowstone Park shows that continued water-rock reactions may occur during ascent of water even though that ascent is so rapid that little or no heat is lost to the country rock, i.e. the water cools adiabatically. As a result of such continued reaction, waters which dissolve additional Ca as they ascend from the aquifer to the surface will yield estimated aquifer temperatures that are too low. On the other hand, waters initially having enough Ca to deposit calcium carbonate during ascent may yield estimated aquifer temperatures that are too high if aqueous Na and K are prevented from further reaction with country rock owing to armoring by calcite or silica minerals. The Na-K-Ca geothermometer is of particular interest to those prospecting for geothermal energy. The method also may be of use in interpreting compositions of fluid inclusions. ?? 1973.
Enhanced upconversion emission in colloidal (NaYF4:Er(3+))/NaYF4 core/shell nanoparticles excited at 1523 nm.

PubMed

Shao, Wei; Chen, Guanying; Damasco, Jossana; Wang, Xianliang; Kachynski, Aliaksandr; Ohulchanskyy, Tymish Y; Yang, Chunhui; Ågren, Hans; Prasad, Paras N

2014-03-15

In this work, we report on efficient visible and near-IR upconversion emissions in colloidal hexagonal-phase core/shell NaYF4:Er(3+)/NaYF4 nanoparticles (∼38 nm) under IR laser excitation at 1523 nm. Varying amounts of Er(3+) dopants were introduced into the core NaYF4:Er(3+) nanoparticles, revealing an optimized Er(3+) concentration of 10% for the highest luminescent efficiency. An inert epitaxial shell layer of NaYF4 grown onto the core of the NaYF4:Er(3+) 10% nanoparticle increased its upconversion emission intensity fivefold due to suppression of surface-related quenching mechanisms, yielding the absolute upconversion efficiency to be as high as ∼3.9±0.3% under an excitation density of 18 W/cm(2). The dependence of the intensity of upconversion emission peaks on laser excitation density in the core/shell nanoparticle displayed "saturation effects" at low excitation density in the range of 1.5-18 W/cm(2), which again demonstrates high upconversion efficiency.
Constraining the astrophysical 23Mg(p, γ)24Al reaction rate using the 23Na(d,p)24Na reaction

NASA Astrophysics Data System (ADS)

Bennett, E. A.; Catford, W. N.; Christian, G.; Dede, S.; Hallam, S.; Lotay, G.; Ota, S.; Saastamoinen, A.; Wilkinson, R.

2017-09-01

The 23Mg(p, γ)24Al reaction provides an escape from the Ne-Na cycle in classical novae and is therefore important in understanding nova nucleosynthesis in the A > 20 mass range. Although several resonances may contribute to the overall rate at novae temperatures, the resonance at 475 keV is thought to be dominant. The strength of this resonance has been directly measured using a radioactive 23Mg beam impinging on a windowless H2 gas target; however, recent high-precision 24Al mass measurements have called this result into question. Here we make an indirect measurement using the 23Na(d,p)24Na reaction in inverse kinematics to study the mirror state of the 475 keV resonance in 24Na. The experiment, performed at the Texas A&M Cyclotron Institute, utilized the TIARA silicon array, four HPGe detectors, and the MDM spectrometer to measure the excited states of the 24Na nucleus. Preliminary results from the experiment will be presented along with progress from the ongoing analysis.
Growth responses and ion accumulation in the halophytic legume Prosopis strombulifera are determined by Na2SO4 and NaCl.

PubMed

Reginato, M; Sosa, L; Llanes, A; Hampp, E; Vettorazzi, N; Reinoso, H; Luna, V

2014-01-01

Halophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera (Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina (Na2SO4, NaCl, or their iso-osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso-osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na(+) accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K(+) supply by maintaining high K(+)/Na(+) discrimination, and maintenance of normal Ca(2+) levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi-saline-treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO4(2-)-induced toxicity by Cl(-). Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.
Elaboration and characterization of solid materials of types zeolite NaA and faujasite NaY exchanged by zinc metallic ions Zn2+

NASA Astrophysics Data System (ADS)

Nibou, D.; Amokrane, S.; Mekatel, H.; Lebaili, N.

2009-11-01

The present work deals with the elaborated of NaA and faujasite NaY solid materials according to a hydrothermal crystallization of amorphous gels composed of solutions of silicon, aluminum and sodium. The process elaboration has been achieved in autoclaves made of steel lined in Teflon under different operating conditions of temperature of heating, time of contact and stirring. After crystallization, the samples were characterized by different techniques such as X ray diffraction, scanning electronic microscopy, infrared spectroscopy, thermal analysis, and chemical analysis. Pure solid materials NaA and NaY zeolites were obtained and were impregnated by (Zn2+) ions by ion exchange process. The effects of various parameters such as initial metal concentration, pH, solid-liquid ratio (R) and temperature on the exchange percentage are studied. The equilibrium isotherms of zinc ions sorption are also evaluated using Langmuir and Freundlich models. Thermodynamic parameters, i.e. enthalpy of adsorption ΔHads∘, entropy change ΔSads∘ and Gibbs free energy ΔGads∘ for the sorption of zinc ions on NaA and NaY zeolites were examined.
The system Na2CO3-CaCO3 at 3 GPa

NASA Astrophysics Data System (ADS)

Podborodnikov, Ivan V.; Shatskiy, Anton; Arefiev, Anton V.; Rashchenko, Sergey V.; Chanyshev, Artem D.; Litasov, Konstantin D.

2018-04-01

It was suggested that alkali-alkaline earth carbonates may have a substantial role in petrological processes relevant to metasomatism and melting of the Earth's mantle. Because natrite, Na2CO3, Na-Ca carbonate (shortite and/or nyerereite), and calcite, CaCO3, have been recently reported from xenoliths of shallow mantle (110-115 km) origin, we performed experiments on phase relations in the system Na2CO3-CaCO3 at 3 GPa and 800-1300 °C. We found that the system has one intermediate compound, Na2Ca3(CO3)4, at 800 °C, and two intermediate compounds, Na2Ca(CO3)2 and Na2Ca3(CO3)4, at 850 °C. CaCO3 crystals recovered from experiments at 950 and 1000 °C are aragonite and calcite, respectively. Maximum solid solution of CaCO3 in Na2CO3 is 20 mol% at 850 °C. The Na-carbonate-Na2Ca(CO3)2 eutectic locates near 860 °C and 56 mol% Na2CO3. Na2Ca(CO3)2 melts incongruently near 880 °C to produce Na2Ca3(CO3)4 and a liquid containing about 51 mol% Na2CO3. Na2Ca3(CO3)4 disappears above 1000 °C via incongruent melting to calcite and a liquid containing about 43 mol% Na2CO3. At 1050 °C, the liquid, coexisting with Na-carbonate, contains 87 mol% Na2CO3. Na-carbonate remains solid up to 1150 °C and melts at 1200 °C. The Na2CO3 content in the liquid coexisting with calcite decreases to 15 mol% as temperature increases to 1300 °C. Considering the present and previous data, a range of the intermediate compounds on the liquidus of the Na2CO3-CaCO3 join changes as pressure increases in the following sequence: Na2Ca(CO3)2 (0.1 GPa) → Na2Ca(CO3)2, Na2Ca3(CO3)4 (3 GPa) → Na4Ca(CO3)3, Na2Ca3(CO3)4 (6 GPa). Thus, the Na2Ca(CO3)2 nyerereite stability field extends to the shallow mantle pressures. Consequently, findings of nyerereite among daughter phases in the melt inclusions in olivine from the sheared garnet peridotites are consistent with their mantle origin.
Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

PubMed Central

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065
Tree branching: Leonardo da Vinci's rule versus biomechanical models.

PubMed

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.
Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na{sub 3}OBr and Na{sub 4}OI{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yonggang, E-mail: yyggwang@gmail.com, E-mail: yangwg@hpstar.ac.cn, E-mail: yusheng.zhao@unlv.edu; Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006; High Pressure Synergetic Consortium

2016-01-14

The structure stability under high pressure and thermal expansion behavior of Na{sub 3}OBr and Na{sub 4}OI{sub 2}, two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temperature. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na{sub 3}OBr and Na{sub 4}OI{sub 2}, respectively. The cubic Na{sub 3}OBr structure and tetragonal Na{sub 4}OI{sub 2} with intergrowth K{sub 2}NiF{sub 4} structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na{sub 4}OI{sub 2} exhibits nearly isotropic compressibility. Negative thermal expansion was observed at lowmore » temperature range (20–80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined and confirmed by first-principles calculations among various possible polymorphisms qualitatively. The results provide in-depth understanding of the negative thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications.« less
Effect of salts (NaCl and Na2CO3) on callus and suspension culture of Stevia rebaudiana for Steviol glycoside production.

PubMed

Gupta, Pratibha; Sharma, Satyawati; Saxena, Sanjay

2014-03-01

Steviol glycosides are natural non-caloric sweeteners which are extracted from the leaves of Stevia rebaudiana plant. Present study deals the effect of salts (NaCl and Na2CO3) on callus and suspension culture of Stevia plant for steviol glycoside (SGs) production. Yellow-green and compact calli obtained from in vitro raised Stevia leaves sub-cultured on MS medium supplemented with 2.0 mg l(-1) NAA and different concentrations of NaCl (0.05-0.20%) and Na2CO3 (0.0125-0.10%) for 2 weeks, and incubated at 24 ± 1 °C and 22.4 μmol m(-2) s(-1) light intensity provided by white fluorescent tubes for 16 h. Callus and suspension biomass cultured on salts showed less growth as well as browning of medium when compared with control. Quantification of SGs content in callus culture (collected on 15th day) and suspension cultures (collected at 10th and 15th days) treated with and without salts were analyzed by HPLC. It was found that abiotic stress induced by the salts increased the concentration of SGs significantly. In callus, the quantity of SGs got increased from 0.27 (control) to 1.43 and 1.57% with 0.10% NaCl, and 0.025% Na2CO3, respectively. However, in case of suspension culture, the same concentrations of NaCl and Na2CO3 enhanced the SGs content from 1.36 (control) to 2.61 and 5.14%, respectively, on the 10th day.
40 CFR 60.42Da - Standard for particulate matter (PM).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for particulate matter (PM). 60.42Da Section 60.42Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR....42Da Standard for particulate matter (PM). (a) On and after the date on which the initial performance...
40 CFR 60.42Da - Standard for particulate matter (PM).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for particulate matter (PM). 60.42Da Section 60.42Da Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR....42Da Standard for particulate matter (PM). (a) On and after the date on which the initial performance...
Raman spectroscopic study of synthesized Na-bearing majoritic garnets

NASA Astrophysics Data System (ADS)

Okamoto, K.

2003-12-01

Majoritic garnets in diamond have been considered as the sample from mantle transition zone (e.g. Moore and Gurney, 1985). For non-destructive, in-situ Raman analysis, Gillet et al. (2002) systematically checked chemistry and Raman peak of various majoritic garnets in diamond. They treated majoritic component as number of excess-silica than 3.0 per formula unit. However, in the basaltic system, majorite garnets also have significant amounts of Na. Na substitution is coupled with Si and Ti as follows; Na +Ti = Ca +Al (Ringwood and Lovering, 1970), Na +Si = Ca + Al (Sobolev and Labrentav, 1971; Ringwood and Major, 1971) or Na + Si = Mg + Al (Gasparik, 1989). Each component in garnet is defined as follows; Mj (majorite) component = ((Si-3)-Na)/2), NaSi (Na2MSi5O12 where M= Ca, Mg, Fe2+) component = (Na-T)/2, and NaTi component = Ti/2. Okamoto and Maruyama (2003) conducted UHP experiments in the MORB + H2O system (KNCFMATSH) at 10-19 GPa. They show that 1) Mj and NaTi component are constant and lower than 0.1 at T = 900 \\deg C, and 2) NaSi component increases drastically above 15 GPa although it is neglibly small at P<15 GPa. Raman spectra was newly analyzed using Okamoto and Maruyama (2003)'s run charges. Above 15 GPa, there is a characteristic sharp peak at 910 cm-1 and broad shoulder between 800 and 900 cm-1 as well as broad band near 960 cm-1. Gillet et at (2002) concluded that the former peak at 910cm-1 is the only reliable signature for the majoritic garnet (Si>3). They also implied that the latter two broad peaks are diagnostic feature for Ti rich garnet (> 1wt% of TiO2) as well as peak at 1030 cm-1. However, in all P range (10-19 GPa) of the present study, TiO2 is higher than 1wt%, and there is a peak at 1030 cm-1. Additional Ti-free experiment at 16 GPa, 1200 \\deg C clearly revealed that Na-bearing majoritic garnet has a significant shoulder at 800-900 cm-1. Ref; Gasparik (1989) CMP, 102,389, Gillet et al. (2002) Am.Min., 87, 312, Moore and Gurney (1985
Thermodynamic Study of Solid-Liquid Equilibrium in NaCl-NaBr-H2O System at 288.15 K

NASA Astrophysics Data System (ADS)

Li, Dan; Meng, Ling-zong; Deng, Tian-long; Guo, Ya-fei; Fu, Qing-Tao

2018-06-01

The solubility data, composition of the solid solution and refractive indices of the NaCl-NaBr-H2O system at 288.15 K were studied with the isothermal equilibrium dissolution method. The solubility diagram and refractive index diagram of this system were plotted at 288.15 K. The solubility diagram consists of two crystallization zones for solid solution Na(Cl,Br) · 2H2O and Na(Cl,Br), one invariant points cosaturated with two solid solution and two univariant solubility isothermal curves. On the basis of Pitzer and Harvie-Weare (HW) chemical models, the composition equations and solubility equilibrium constant equations of the solid solutions at 288.15 K were acquired using the solubility data, the composition of solid solutions, and binary Pitzer parameters. The solubilities calculated using the new method combining the equations are in good agreement with the experimental data.
A Kinetic Characterization of the Gill (Na+, K+)-ATPase from the Semi-terrestrial Mangrove Crab Cardisoma guanhumi Latreille, 1825 (Decapoda, Brachyura).

PubMed

Farias, Daniel L; Lucena, Malson N; Garçon, Daniela P; Mantelatto, Fernando L; McNamara, John C; Leone, Francisco A

2017-10-01

We provide a kinetic characterization of (Na + , K + )-ATPase activity in a posterior gill microsomal fraction from the semi-terrestrial mangrove crab Cardisoma guanhumi. Sucrose density gradient centrifugation reveals two distinct membrane fractions showing considerable (Na + , K + )-ATPase activity, but also containing other microsomal ATPases. The (Na + , K + )-ATPase, notably immuno-localized to the apical region of the epithelial pillar cells, and throughout the pillar cell bodies, has an M r of around 110 kDa and hydrolyzes ATP with V M = 146.8 ± 6.3 nmol Pi min -1 mg protein -1 and K M = 0.05 ± 0.003 mmol L -1 obeying Michaelis-Menten kinetics. While stimulation by Na + (V M = 139.4 ± 6.9 nmol Pi min -1 mg protein -1 , K M = 4.50 ± 0.22 mmol L -1 ) also follows Michaelis-Menten kinetics, modulation of (Na + , K + )-ATPase activity by MgATP (V M = 136.8 ± 6.5 nmol Pi min -1 mg protein -1 , K 0.5 = 0.27 ± 0.04 mmol L -1 ), K + (V M = 140.2 ± 7.0 nmol Pi min -1 mg protein -1 , K 0.5 = 0.17 ± 0.008 mmol L -1 ), and NH 4 + (V M = 149.1 ± 7.4 nmol Pi min -1 mg protein -1 , K 0.5 = 0.60 ± 0.03 mmol L -1 ) shows cooperative kinetics. Ouabain (K I = 52.0 ± 2.6 µmol L -1 ) and orthovanadate (K I = 1.0 ± 0.05 µmol L -1 ) inhibit total ATPase activity by around 75%. At low Mg 2+ concentrations, ATP is an allosteric modulator of the enzyme. This is the first study to provide a kinetic characterization of the gill (Na + , K + )-ATPase in C. guanhumi, and will be useful in better comprehending the biochemical underpinnings of osmoregulatory ability in a semi-terrestrial mangrove crab.
Phase diagram of the LiNO3-NaNO3-NaCl-Sr(NO3)2 salt system

NASA Astrophysics Data System (ADS)

Rasulov, A. I.; Gasanaliev, A. M.; Mamedova, A. K.; Gamataeva, B. Yu.

2015-04-01

The phase diagram of the quaternary LiNO3-NaNO3-NaCl-Sr(NO3)2 system is studied by means of differential thermal analysis, and the compositions and crystallization temperatures of nonvariant equilibrium phases are revealed. The temperature dependence of conductivity in eutectic and peritectic salt compositions is investigated.
33 CFR 147.833 - Na Kika FDS safety zone.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description. Na...

33 CFR 147.833 - Na Kika FDS safety zone.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description. Na...
Intracellular Requirements for Passive Proton Transport through the Na+,K+-ATPase.

PubMed

Stanley, Kevin S; Meyer, Dylan J; Gatto, Craig; Artigas, Pablo

2016-12-06

The Na + ,K + -ATPase (NKA or Na/K pump) hydrolyzes one ATP to exchange three intracellular Na+ (Na + i ) for two extracellular K+ (K + o ) across the plasma membrane by cycling through a set of reversible transitions between phosphorylated and dephosphorylated conformations, alternately opening ion-binding sites externally (E2) or internally (E1). With subsaturating [Na + ] o and [K + ] o , the phosphorylated E2P conformation passively imports protons generating an inward current (I H ), which may be exacerbated in NKA-subunit mutations associated with human disease. To elucidate the mechanisms of I H , we studied the effects of intracellular ligands (transported ions, nucleotides, and beryllium fluoride) on I H and, for comparison, on transient currents measured at normal Na + o (Q Na ). Utilizing inside-out patches from Xenopus oocytes heterologously expressing NKA, we observed that 1) in the presence of Na + i , I H and Q Na were both activated by ATP, but not ADP; 2) the [Na + ] i dependence of I H in saturating ATP showed K 0.5,Na = 1.8 ± 0.2 mM and the [ATP] dependence at saturating [Na + ] i yielded K 0.5,ATP = 48 ± 11 μM (in comparison, Na + i -dependent Q Na yields K 0.5,Na = 0.8 ± 0.2 mM and K 0.5,ATP = 0.43 ± 0.03 μM; 3) ATP activated I H in the presence of K + i (∼15% of the I H observed in Na + i ) only when Mg 2+ i was also present; and 4) beryllium fluoride induced maximal I H even in the absence of nucleotide. These data indicate that I H occurs when NKA is in an externally open E2P state with nucleotide bound, a conformation that can be reached through forward Na/K pump phosphorylation of E1, with Na + i and ATP, or by backward binding of K + i to E1, which drives the pump to the occluded E2(2K), where free P i (at the micromolar levels found in millimolar ATP solutions) promotes external release of occluded K + by backdoor NKA phosphorylation. Maximal I H through beryllium-fluorinated NKA indicates that this complex mimics ATP
Dependence of renal (Na+ + k+)-adenosine triphosphatase activity on thyroid status.

PubMed

Lo, S C; August, T R; Liberman, U A; Edelman, I S

1976-12-25

In thyroidectomized rats, a single injection of L-2,,5,2'-triiodothyronine (T3) (50mug/100 g body weight) elicited at 45% increase in (Na+ + k+)-dependent adenosine triphosphatase (NaK-ATPase) activity of the membrane-rich fraction of renal cortex at the optimal time of response, 48 h after injection. Three successive doses of T3 (50 mug/100 g body weight), given on alternate days, increased NaK-ATPase by 67% in the renal cortex but had no significant effect on the outer medulla or the papilla. Moreover, T3 had no effect on Mg2+-dependent adenosine trisphatase (MgATPase) in cortex, cedulla, or papilla. Three doses of T3 (50 mug/100 g body weight) given on alternate days to thyroidectomized rats elecited a 134, 79, and 46% increase in Vmax for ATP, Na4, and K+, respectively. There were no changes in the Km for ATP or the K1/2 values for Na+ and K+. Two methods were used to estimate the effect of T3 on the number of NaK-ATPase units (assumed to represent the number of Na+ pump sites); rat renal plasma membrane fractions were incubated with [gamma-32P]ATP, Mg2+, and Na+; the 32P-labeled membrane protein yeild was quantitatively dependent on Na+ and was hydrolyzed on addition of K+. There was a linear correlation between the specific activity of NaK-ATPase (Vmax) and the amount of phosphorylated intermediate formed, in renal cortical membrane fractions from thyroidectomized rats given T3 or the diluent. There was also a linear correlation between the specific activity of NaK-ATPase (Vmax) and the amount of [3H]ouabain specifically bound (Na+-, Mg2+-, APT-dependent) to the NaK-ATPase preparation. Injection of T3 resulted in a 70% increase in NaK-ATPase activity, a 79% increase in formation of the phosphorylated intermediate, and a 65% increase in the [H]ouabain specifically bound to the NaK-ATPase system. The T3-dependent increases in Vmax for ATP, Na+, and K+ and the proportionate increases in the phosphorylated intermediate and in the amount of [3H]ouabain bound
Risk factors for left ventricular hypertrophy: role of Na(+)-Li+ countertransport.

PubMed

Neves, P L; Faisca, M; Gomes, V; Cacodcar, S; Bernardo, I; Anunciada, A I; Viegas, E; Martins, H; da Silva, A M

1996-06-01

Left ventricular hypertrophy (LVH) is associated with an increase in cardiovascular death in essential hypertension (EH). The factors involved in LVH are multiple and complex. We looked for risk factors of LVH in a group of 28 nonobese patients with EH (mean age = 45.3 years). We analyzed the activity of several erythrocyte ion transports (Vmax of NaLi countertransport, NaKCl cotransport and NaK-pump, and the Na-leak Kp Na), the intracellular Na and the insulin sensitivity index. All these parameters were used as independent variables whereas the left ventricular mass index (LVMI) was used as the dependent variable. Variables showing a significant univariate correlation (age, time of EH, mean blood pressure and Vmax of NaLi countertransport) were introduced in a stepwise multiple regression model. Only age (P = 0.014), time of EH (P = 0.038) and Vmax of NaLi countertransport (P = 0.032) were independently associated with LVMI (R2 = 0.581, P = 0.0001). The NaLi CT, an operating mode of the NaH exchanger that facilitates cellular growth, may be a marker of LVH, and consequently a marker of increased cardiovascular risk.
Effect of Solids-To-Liquids, Na2SiO3-To-NaOH and Curing Temperature on the Palm Oil Boiler Ash (Si + Ca) Geopolymerisation System

PubMed Central

Yahya, Zarina; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Abd Razak, Rafiza; Sandu, Andrei Victor

2015-01-01

This paper investigates the effect of the solids-to-liquids (S/L) and Na2SiO3/NaOH ratios on the production of palm oil boiler ash (POBA) based geopolymer. Sodium silicate and sodium hydroxide (NaOH) solution were used as alkaline activator with a NaOH concentration of 14 M. The geopolymer samples were prepared with different S/L ratios (0.5, 1.0, 1.25, 1.5, and 1.75) and Na2SiO3/NaOH ratios (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0). The main evaluation techniques in this study were compressive strength, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM). The results showed that the maximum compressive strength (11.9 MPa) was obtained at a S/L ratio and Na2SiO3/NaOH ratio of 1.5 and 2.5 at seven days of testing.
Biochemical characterization of L-asparaginase in NaCl-tolerant Staphylococcus sp. OJ82 isolated from fermented seafood.

PubMed

Han, Sangwon; Jung, Jaejoon; Park, Woojun

2014-08-01

L-Asparaginase from gram-positive bacteria has been poorly explored. We conducted recombinant overexpression and purification of L-asparaginase from Staphylococcus sp. OJ82 (SoAsn) isolated from Korean fermented seafood to evaluate its biotechnological potential as an antileukemic agent. SoAsn was expressed in Escherichia coli BL21 (DE3) with an estimated molecular mass of 37.5 kDa, determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Consistent with asparaginases in gram-negative bacteria, size-exclusion chromatography determined SoAsn as a homodimer. Interestingly, the optimal temperature of SoAsn was 37°C and over 90% of activity was retained between 37°C and 50°C, and its thermal stability range was narrower than that of commercial E. coli L-asparaginase (EcAsn). Both SoAsn and EcAsn were active between pH 9 and 10, although their overall pH-dependent enzyme activities were slightly different. The Km value of SoAsn was 2.2 mM, which is higher than that of EcAsn. Among eight metals tested for enzyme activity, cobalt and magnesium greatly enhanced the SoAsn and EcAsn activity, respectively. Interestingly, SoAsn retained more than 60% of its activity under 2 M NaCl condition, but the activity of EcAsn was reduced to 48%. Overall, the biochemical characteristics of SoAsn were similar to those of EcAsn, but its kinetics, cofactor requirements, and NaCl tolerance differed from those of EcAsn.
Na intercalation in Fe-MIL-100 for aqueous Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chavez, James S.; Harrison, Katharine L.; Sava Gallis, Dorina F.

Here we report for the first time the feasibility of using metal–organic frameworks (MOFs) as electrodes for aqueous Na-ion batteries. We show that Fe-MIL-100, a known redox-active MOF, is electrochemically active in a Na aqueous electrolyte, under various compositions. Emphasis was placed on investigating the electrode–electrolyte interface, with a focus on identifying the relationship between additives in the composition of the working electrode, particle size and overall performance. We found that the energy storage capacity is primarily dependent on the binder additive in the composite; the best activity for this MOF is obtained with Nafion as a binder, owing tomore » its hydrophilic and ion conducting nature. Kynar-bound electrodes are clearly less effective, due to their hydrophobic character, which impedes wetting of the electrode. The binder-free systems show the poorest electrochemical activity. There is little difference in the overall performance as function of particle size (micro vs. nano), implying the storage capacities in this study are not limited by ionic and/or electronic conductivity. Excellent reversibility and high coulombic efficiency are achieved at higher potential ranges, observed after cycle 20. That is despite progressive capacity decay observed in the initial cycles. Importantly, structural analyses of cycled working electrodes confirm that the long range crystallinity remains mainly unaltered with cycling. These findings suggest that limited reversibility of the intercalated Na ions in the lower potential range, together with the gradual lack of available active sites in subsequent cycles is responsible for the rapid decay in capacity retention.« less
Na intercalation in Fe-MIL-100 for aqueous Na-ion batteries

DOE PAGES

Chavez, James S.; Harrison, Katharine L.; Sava Gallis, Dorina F.

2017-05-04

Here we report for the first time the feasibility of using metal–organic frameworks (MOFs) as electrodes for aqueous Na-ion batteries. We show that Fe-MIL-100, a known redox-active MOF, is electrochemically active in a Na aqueous electrolyte, under various compositions. Emphasis was placed on investigating the electrode–electrolyte interface, with a focus on identifying the relationship between additives in the composition of the working electrode, particle size and overall performance. We found that the energy storage capacity is primarily dependent on the binder additive in the composite; the best activity for this MOF is obtained with Nafion as a binder, owing tomore » its hydrophilic and ion conducting nature. Kynar-bound electrodes are clearly less effective, due to their hydrophobic character, which impedes wetting of the electrode. The binder-free systems show the poorest electrochemical activity. There is little difference in the overall performance as function of particle size (micro vs. nano), implying the storage capacities in this study are not limited by ionic and/or electronic conductivity. Excellent reversibility and high coulombic efficiency are achieved at higher potential ranges, observed after cycle 20. That is despite progressive capacity decay observed in the initial cycles. Importantly, structural analyses of cycled working electrodes confirm that the long range crystallinity remains mainly unaltered with cycling. These findings suggest that limited reversibility of the intercalated Na ions in the lower potential range, together with the gradual lack of available active sites in subsequent cycles is responsible for the rapid decay in capacity retention.« less
The role of transparency in da Vinci stereopsis.

PubMed

Zannoli, Marina; Mamassian, Pascal

2011-10-15

The majority of natural scenes contains zones that are visible to one eye only. Past studies have shown that these monocular regions can be seen at a precise depth even though there are no binocular disparities that uniquely constrain their locations in depth. In the so-called da Vinci stereopsis configuration, the monocular region is a vertical line placed next to a binocular rectangular occluder. The opacity of the occluder has been mentioned to be a necessary condition to obtain da Vinci stereopsis. However, this opacity constraint has never been empirically tested. In the present study, we tested whether da Vinci stereopsis and perceptual transparency can interact using a classical da Vinci configuration in which the opacity of the occluder varied. We used two different monocular objects: a line and a disk. We found no effect of the opacity of the occluder on the perceived depth of the monocular object. A careful analysis of the distribution of perceived depth revealed that the monocular object was perceived at a depth that increased with the distance between the object and the occluder. The analysis of the skewness of the distributions was not consistent with a double fusion explanation, favoring an implication of occlusion geometry in da Vinci stereopsis. A simple model that includes the geometry of the scene could account for the results. In summary, the mechanism responsible to locate monocular regions in depth is not sensitive to the material properties of objects, suggesting that da Vinci stereopsis is solved at relatively early stages of disparity processing. Copyright © 2011 Elsevier Ltd. All rights reserved.
Pacemaker rate and depolarization block in nigral dopamine neurons: a somatic sodium channel balancing act

PubMed Central

Tucker, Kristal R.; Huertas, Marco A.; Horn, John P.; Canavier, Carmen C.; Levitan, Edwin S.

2012-01-01

Midbrain dopamine (DA) neurons are slow intrinsic pacemakers that undergo depolarization (DP) block upon moderate stimulation. Understanding DP block is important because it has been correlated with the clinical efficacy of chronic antipsychotic drug treatment. Here we describe how voltage-gated sodium (NaV) channels regulate DP block and pacemaker activity in DA neurons of the substantia nigra using rat brain slices. The distribution, density and gating of NaV currents were manipulated by blocking native channels with tetrodotoxin and by creating virtual channels and anti-channels with dynamic clamp. Although action potentials initiate in the axon initial segment (AIS) and NaV channels are distributed in multiple dendrites, selective reduction of NaV channel activity in the soma was sufficient to decrease pacemaker frequency and increase susceptibility to DP block. Conversely, increasing somatic NaV current density raised pacemaker frequency and lowered susceptibility to DP block. Finally, when NaV currents were restricted to the soma, pacemaker activity occurred at abnormally high rates due to excessive local subthreshold NaV current. Together with computational simulations, these data show that both the slow pacemaker rate and the sensitivity to DP block that characterizes DA neurons result from the low density of somatic NaV channels. More generally, we conclude that the somatodendritic distribution of NaV channels is a major determinant of repetitive spiking frequency. PMID:23077037
High Pressure Strength Study on NaCl

NASA Astrophysics Data System (ADS)

Mi, Z.; Shieh, S. R.; High Pressure Mineral Physics Group

2010-12-01

Yield strength is regarded as one important property related to rheological characteristics of minerals in the Earth’s interior. The strength study of NaCl, a popular pressure medium in static high pressure experiments, has been carried out under non-hydrostatic conditions in a diamond anvil cell up to 43 GPa at room temperature using radial energy dispersive X-ray diffraction technique. Phase transformation from B1 (rock salt structure) to B2 (CsCl structure) starts at 29.4 GPa, and is complete at 32.1 GPa. Bulk modulus obtained by third order Birch-Manurgham equation of state is 25.5 GPa with pressure derivative 4.6 for B1 phase, and 30.78 GPa with pressure derivative 4.32 GPa for B2 phase, which are in a good agreement with previous studies. The differential stress of NaCl B1 phase shows very gentle increase with pressure, which indicates that NaCl is a very good pressure-transmitting medium at pressure below 30 GPa. However, the differential stress increases more abruptly for B2 phase and this may imply that NaCl can no longer be regarded as a “soft” pressure medium at very high pressures. For B1 phase, (111) is the strongest plane and (200) is the weakest plane, while (200) becomes the strongest plane in B2 phase. Pure NaCl is weaker than mixture MgO and NaCl, which indicates that soft material become stronger when mixed with hard material. The yield strength of B2 obtained through energy dispersive X-ray diffraction technique increase linearly, while the value derived by pressure gradient method shows jagged trend.
POLYCYCLIC AROMATIC HYDROCARBONS ASSESSMENT IN SEDIMENT OF NATIONAL PARKS IN SOUTHEAST BRAZIL

PubMed Central

Meire, Rodrigo Ornellas; Azeredo, Antonio; de Souza Pereira, Márcia; Paulo, João; Torres, Machado; Malm, Olaf

2008-01-01

The aim of this work was to assess the levels of polycyclic aromatic hydrocarbons (PAHs) in the environment and their sources found in protected regions of southeastern Brazil. Samples of sediments were collected at four National Parks: Itatiaia National Park (PNIT), Serra da Bocaina National Park (PNSB), Serra dos Orgãos National Park (PNSO) and Jurubatiba National Park (PNJUB). The National Parks studied comprise rainforests, altitudinal fields and ‘restinga’ environments located in the Minas Gerais, Rio de Janeiro and São Paulo states. The sampling was conducted between 2002 and 2004 from June to September. In general, the environmental levels of PAHs found were similar to those in other remote areas around the globe. PNIT exhibited the highest median values of total PAHs in sediment (97 ng·g−1), followed by PNJUB (89 ng·g−1), PNSO (57 ng·g−1) and PNSB (27 ng·g−1). The highest levels of total PAHs (576 and 24430 ng·g−1) could be associated to a point source contamination where are characterizated for human activities. At PNSB and PNIT the PAH profiles were richer in 2 and 3 ring compounds, whereas at PNSO and PNJUB, the profiles exhibited 3 and 4 ring compounds. The phenanthrene predominance in most samples could indicate the influence of biogenic synthesis. The samples with a petrogenic pattern found in this study might be associated with the vicinity of major urban areas, highway traffic and/or industrial activities close to PNSO and PNIT. At PNIT and PNJUB, forest fires and slash and burn agricultural practices may drive the results towards a pyrolytic pattern. PMID:18472130
Polycyclic aromatic hydrocarbons assessment in sediment of national parks in southeast Brazil.

PubMed

Meire, Rodrigo Ornellas; Azeredo, Antonio; Pereira, Márcia de Souza; Torres, João Paulo Machado; Malm, Olaf

2008-08-01

The aim of this work was to assess the levels of polycyclic aromatic hydrocarbons (PAHs) in the environment and their sources found in protected regions of southeastern Brazil. Samples of sediments were collected at four National Parks: Itatiaia National Park (PNIT), Serra da Bocaina National Park (PNSB), Serra dos Orgãos National Park (PNSO) and Jurubatiba National Park (PNJUB). The National Parks studied comprise rainforests, altitudinal fields and 'restinga' environments located in the Minas Gerais, Rio de Janeiro and São Paulo states. The sampling was conducted between 2002 and 2004 from June to September. In general, the environmental levels of PAHs found were similar to those in other remote areas around the globe. PNIT exhibited the highest median values of total PAHs in sediment (97 ng g(-1)), followed by PNJUB (89 ng g(-1)), PNSO (57 ng g(-1)) and PNSB (27 ng g(-1)). The highest levels of total PAHs (576 and 24430 ng g(-1)) could be associated to a point source contamination where are characterized for human activities. At PNSB and PNIT the PAH profiles were richer in 2 and 3 ring compounds, whereas at PNSO and PNJUB, the profiles exhibited 3 and 4 ring compounds. The phenanthrene predominance in most samples could indicate the influence of biogenic synthesis. The samples with a petrogenic pattern found in this study might be associated with the vicinity of major urban areas, highway traffic and/or industrial activities close to PNSO and PNIT. At PNIT and PNJUB, forest fires and slash and burn agricultural practices may drive the results towards a pyrolytic pattern.
Mercury Na exospheric emission related to solar disturbances

NASA Astrophysics Data System (ADS)

Orsini, S.; Mangano, V.; Milillo, A.; Plainaki, C.; Mura, A.; Massetti, S.; Raines, J. M.; De Angelis, E.; Rispoli, R.; Lazzarotto, F.; Aronica, A.

2017-09-01

A first attempt to use Na exospheric emission at Mercury as a proxy of CME transit is presented, in a kind of planetary space weather. The link existing between the dayside exosphere Na pattern at Mercury and the solar wind-magnetosphere-surface interactions is investigated. This goal is pursued by analyzing the Na hourly average distributions, as observed by the ground-based THEMIS solar telescope during 10 selected periods between 2012 and 2013 (seeing <2"), when also data from MESSENGER were available. Very often a two-peak pattern of variable intensity is observed, symmetrically located at high latitudes in both hemispheres. Occasionally, the signal is instead diffused above the sub-solar region. We compare these different Na emission patterns with the time profiles of proton fluxes and magnetic field data, as measured in-situ by MESSENGER. Among these 10 cases, only in one occasion the Na signal is all the time diffused above the subsolar region, and only in this case the MESSENGER data indicate the occurrence of significant solar CME perturbations.
Localization and Function of the Membrane-bound Riboflavin in the Na+-translocating NADH:Quinone Oxidoreductase (Na+-NQR) from Vibrio cholerae*

PubMed Central

Casutt, Marco S.; Huber, Tamara; Brunisholz, René; Tao, Minli; Fritz, Günter; Steuber, Julia

2010-01-01

The sodium ion-translocating NADH:quinone oxidoreductase (Na+-NQR) from the human pathogen Vibrio cholerae is a respiratory membrane protein complex that couples the oxidation of NADH to the transport of Na+ across the bacterial membrane. The Na+-NQR comprises the six subunits NqrABCDEF, but the stoichiometry and arrangement of these subunits are unknown. Redox-active cofactors are FAD and a 2Fe-2S cluster on NqrF, covalently attached FMNs on NqrB and NqrC, and riboflavin and ubiquinone-8 with unknown localization in the complex. By analyzing the cofactor content and NADH oxidation activity of subcomplexes of the Na+-NQR lacking individual subunits, the riboflavin cofactor was unequivocally assigned to the membrane-bound NqrB subunit. Quantitative analysis of the N-terminal amino acids of the holo-complex revealed that NqrB is present in a single copy in the holo-complex. It is concluded that the hydrophobic NqrB harbors one riboflavin in addition to its covalently attached FMN. The catalytic role of two flavins in subunit NqrB during the reduction of ubiquinone to ubiquinol by the Na+-NQR is discussed. PMID:20558724
Growth mechanism and magnetic and electrochemical properties of Na{sub 0.44}MnO{sub 2} nanorods as cathode material for Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demirel, S.; Oz, E.; Altin, E.

Nanorods of Na{sub 0.44}MnO{sub 2} are a promising cathode material for Na-ion batteries due to their large surface area and single crystalline structure. We report the growth mechanism of Na{sub 0.44}MnO{sub 2} nanorods via solid state synthesis and their physical properties. The structure and the morphology of the Na{sub 0.44}MnO{sub 2} nanorods are investigated by X-ray diffraction (XRD), scanning and tunneling electron microscopy (SEM and TEM), and energy-dispersive X-ray (EDX) techniques. The growth mechanism of the rods is investigated and the effects of vapor pressure and partial melting of Na-rich regions are discussed. The magnetic measurements show an antiferromagnetic phasemore » transition at 25 K and the μ{sub eff} is determined as 3.41 and 3.24 μ{sub B} from the χ–T curve and theoretical calculation, respectively. The electronic configuration and spin state of Mn{sup 3+} and Mn{sup 4+} are discussed in detail. The electrochemical properties of the cell fabricated using the nanorods are investigated and the peaks in the voltammogram are attributed to the diffusion of Na ions from different sites. Na intercalation process is explained by one and two Margules and van Laar models. - Highlights: • We synthesized Na{sub 0.44}MnO{sub 2} nanorods via a simple solid state reaction technique. • Our studies show that excess Na plays a crucial role in the nanorod formation. • Magnetization measurements show that Mn{sup 3+} ions are in LS and HS states. • The electrochemical properties of the cell fabricated using the nanorods are investigated. • Na intercalation process is explained by one and two Margules and van Laar models.« less
Recent results and prospects for NA62 experiment

NASA Astrophysics Data System (ADS)

Martellotti, Silvia; Aglieri Rinella, G.; Aliberti, R.; Ambrosino, F.; Ammendola, R.; Angelucci, B.; Antonelli, A.; Anzivino, G.; Arcidiacono, R.; Azhinenko, I.; Balev, S.; Barbanera, M.; Bendotti, J.; Biagioni, A.; Bician, L.; Biino, C.; Bizzeti, A.; Blazek, T.; Blik, A.; Bloch-Devaux, B.; Bolotov, V.; Bonaiuto, V.; Boretto, M.; Bragadireanu, M.; Britton, D.; Britvich, G.; Brunetti, M. B.; Bryman, D.; Bucci, F.; Butin, F.; Capitolo, E.; Capoccia, C.; Capussela, T.; Cassese, A.; Catinaccio, A.; Cecchetti, A.; Ceccucci, A.; Cenci, P.; Cerny, V.; Cerri, C.; Checcucci, B.; Chikilev, O.; Chiozzi, S.; Ciaranfi, R.; Collazuol, G.; Conovaloff, A.; Cooke, P.; Cooper, P.; Corradi, G.; Cortina Gil, E.; Costantini, F.; Cotorobai, F.; Cotta Ramusino, A.; Coward, D.; D'Agostini, G.; Dainton, J.; Dalpiaz, P.; Danielsson, H.; Degrange, J.; De Simone, N.; Di Filippo, D.; Di Lella, L.; Di Lorenzo, S.; Dixon, N.; Doble, N.; Dobrich, B.; Duk, V.; Elsha, V.; Engelfried, J.; Enik, T.; Estrada, N.; Falaleev, V.; Fantechi, R.; Fascianelli, V.; Federici, L.; Fedotov, S.; Fiorini, M.; Fry, J.; Fu, J.; Fucci, A.; Fulton, L.; Gallorini, S.; Galeotti, S.; Gamberini, E.; Gatignon, L.; Georgiev, G.; Gianoli, A.; Giorgi, M.; Giudici, S.; Glonti, L.; Goncalves Martins, A.; Gonnella, F.; Goudzovski, E.; Guida, R.; Gushchin, E.; Hahn, F.; Hallgren, B.; Heath, H.; Herman, F.; Husek, T.; Hutanu, O.; Hutchcroft, D.; Iacobuzio, L.; Iacopini, E.; Imbergamo, E.; Jamet, O.; Jarron, P.; Jones, E.; Kampf, K.; Kaplon, J.; Kekelidze, V.; Kholodenko, S.; Khoriauli, G.; Khotyantsev, A.; Khudyakov, A.; Kiryushin, Yu.; Kleimenova, A.; Kleinknecht, K.; Kluge, A.; Koval, M.; Kozhuharov, V.; Krivda, M.; Kucerova, Z.; Kudenko, Y.; Kunze, J.; Lamanna, G.; Latino, G.; Lazzeroni, C.; Lehmann-Miotto, G.; Lenci, R.; Lenti, M.; Leonardi, E.; Lichard, P.; Lietava, R.; Litov, L.; Lollini, R.; Lomidze, D.; Lonardo, A.; Lupi, M.; Lurkin, N.; McCormick, K.; Madigozhin, D.; Maire, G.; Mandeiro, C.; Mannelli, I.; Mannocchi, G.; Mapelli, A.; Marchetto, F.; Marchevski, R.; Martellotti, S.; Massarotti, P.; Massri, K.; Matak, P.; Maurice, E.; Mefodev, A.; Menichetti, E.; Minucci, E.; Mirra, M.; Misheva, M.; Molokanova, N.; Morant, J.; Morel, M.; Moulson, M.; Movchan, S.; Munday, D.; Napolitano, M.; Neri, I.; Newson, F.; Norton, A.; Noy, M.; Nuessle, G.; Numao, T.; Obraztsov, V.; Ostankov, A.; Padolski, S.; Page, R.; Palladino, V.; Paoluzzi, G.; Parkinson, C.; Pedreschi, E.; Pepe, M.; Perez Gomez, F.; Perrin-Terrin, M.; Peruzzo, L.; Petrov, P.; Petrucci, F.; Piandani, R.; Piccini, M.; Pietreanu, D.; Pinzino, J.; Polenkevich, I.; Pontisso, L.; Potrebenikov, Yu.; Protopopescu, D.; Raffaelli, F.; Raggi, M.; Riedler, P.; Romano, A.; Rubin, P.; Ruggiero, G.; Russo, V.; Ryjov, V.; Salamon, A.; Salina, G.; Samsonov, V.; Santoni, C.; Saracino, G.; Sargeni, F.; Semenov, V.; Sergi, A.; Serra, M.; Shaikhiev, A.; Shkarovskiy, S.; Skillicorn, I.; Soldi, D.; Sotnikov, A.; Sougonyaev, V.; Sozzi, M.; Spadaro, T.; Spinella, F.; Staley, R.; Sturgess, A.; Sutcliffe, P.; Szilasi, N.; Tagnani, D.; Trilov, S.; Valdata-Nappi, M.; Valente, P.; Vasile, M.; Vassilieva, T.; Velghe, B.; Veltri, M.; Venditti, S.; Vicini, P.; Volpe, R.; Vormstein, M.; Wahl, H.; Wanke, R.; Wertelaers, P.; Winhart, A.; Winston, R.; Wrona, B.; Yushchenko, O.; Zamkovsky, M.; Zinchenko, A.; NA62 Collaboration

2017-04-01

The K+ →π+ ν ν ‾ decay is theoretically one of the cleanest meson decays and so a good place to look for indirect effects of new physics complementary to LHC searches. The NA62 experiment at CERN is designed to measure the branching ratio of this decay with 10% precision. NA62 was commissioned in October 2014, took data in pilot runs in 2014 and 2015. The NA62 experimental setup is illustrated and data quality is reported.
Origin of high Coulombic loss during sodiation in Na-Sn battery

NASA Astrophysics Data System (ADS)

Byeon, Young-Woon; Choi, Yong-Seok; Ahn, Jae-Pyoung; Lee, Jae-Chul

2017-03-01

Electrochemical sodiation is performed in crystalline Sn foil using in situ scanning electron microscopy (SEM) to simultaneously measure the changes in the electrical resistivity and volume of the Sn anode in a Na-Sn battery. We observe that sodiation causes an increase in the Sn anode resistivity by six orders of magnitude. Ab initio molecular dynamics simulations of the Na-Sn alloy system demonstrate that the increased resistivity of the anode is caused by the formation of an electrically resistive amorphous NaSn phase (a-NaSn) with a pseudogap. It is also observed that the formation of a-NaSn is always accompanied by a large volume expansion of ∼200%, causing the development of residual tensile stress. The residual stress in turn alters the electronic structure of the a-NaSn phase, further increasing the resistivity of a-NaSn and thus decreasing the energy efficiency of the Na-Sn battery.
Effect of shorter dark adaptation on ISCEV standard DA 0.01 and DA 3 skin ERGs in healthy adults.

PubMed

Hamilton, R; Graham, K

2016-08-01

To quantify dark-adapted (DA) skin ERG changes during 20 min of dark adaptation. Sixteen healthy adult subjects were dark-adapted for 20 min during which ISCEV standard dim (0.01 phot cd s m(-2)) white flash ERGs were recorded at 1, 2, 3, 4, 5, 10, 15 and 20 min, and bright (3 phot cd s m(-2)) white ERGs were recorded at 2, 5, 10, 15 and 20 min without mydriasis and using skin electrodes. Amplitudes and peak times were normalised to 20 min values. Halving dark adaptation from 20 to 10 min had no measureable effect on the DA 3 ERG and caused a 10 % amplitude loss (range 0-23 %) only for the DA 0.01 ERG b-wave amplitude. No significant peak time changes resulted, nor increased parameter variability. Reducing dark adaptation from 20 to 10 min or even less has an effect on only DA 0.01 ERGs. Shorter dark adaptation than 20 min may not compromise the clinical utility of the ERG providing clinics adhere to the usual standards of adequate reference data.
Mutant N143P Reveals How Na[superscript +] Activates Thrombin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Weiling; Chen, Zhiwei; Bush-Pelc, Leslie A.

2010-01-12

The molecular mechanism of thrombin activation by Na{sup +} remains elusive. Its kinetic formulation requires extension of the classical Botts-Morales theory for the action of a modifier on an enzyme to correctly account for the contribution of the E*, E, and E:Na{sup +} forms. The extended scheme establishes that analysis of k{sub cat} unequivocally identifies allosteric transduction of Na{sup +} binding into enhanced catalytic activity. The thrombin mutant N143P features no Na{sup +}-dependent enhancement of k{sub cat} yet binds Na{sup +} with an affinity comparable to that of wild type. Crystal structures of the mutant in the presence and absencemore » of Na{sup +} confirm that Pro{sup 143} abrogates the important H-bond between the backbone N atom of residue 143 and the carbonyl O atom of Glu{sup 192}, which in turn controls the orientation of the Glu{sup 192}-Gly{sup 193} peptide bond and the correct architecture of the oxyanion hole. We conclude that Na{sup +} activates thrombin by securing the correct orientation of the Glu{sup 192}-Gly{sup 193} peptide bond, which is likely flipped in the absence of cation. Absolute conservation of the 143-192 H-bond in trypsin-like proteases and the importance of the oxyanion hole in protease function suggest that this mechanism of Na{sup +} activation is present in all Na{sup +}-activated trypsin-like proteases.« less

Validation of estimating food intake in gray wolves by 22Na turnover

USGS Publications Warehouse

DelGiudice, G.D.; Duquette, L.S.; Seal, U.S.; Mech, L.D.

1991-01-01

We studied 22sodium (22Na) turnover as a means of estimating food intake in 6 captive, adult gray wolves (Canis lupus) (2 F, 4 M) over a 31-day feeding period. Wolves were fed white-tailed deer (Odocoileus virginianus) meat only. Mean mass-specific exchangeable Na pool was 44.8 .+-. 0.7 mEq/kg; there was no differeence between males and females. Total exchangeable Na was related (r2 = 0.85, P < 0.009) to body mass. Overall, 22Na turnover overestimated Na intake by 9.8 .+-. 2.4% after 32 days. Actual Na intake was similar in males and females; however, Na turnover (P < 0.05) and the discrepancy (P < 0.01) between turnover and actual Na intake were greater in females than males. From Day 8 to the end of the study, the absolute difference (mEq) between Na intake and Na turnover remained stable. Sodium turnover (mEq/kg/day) was a reliable (r2 = 0.91, P < 0.001) estimator of food consumption (g/kg/day) in wolves over a 32-day period. Sampling blood and weighing wolves every 1-4 days permitted identification of several potential sources of error, including changes in size of exchangeable Na pools, exchange of 22Na with gastrointestinal and bone Na, and rapid loss of the isotope by urinary excretion.
Spray-dried chitosan/acid/NaCl microparticles enhance saltiness perception.

PubMed

Yi, Cheng; Tsai, Min-Lang; Liu, Tristan

2017-09-15

The composition, physicochemical properties and salinity of spray-dried chitosan/acid/NaCl microparticles were tested to ensure a low-sodium and high-salinity salty agent. The spray-dried chitosan/acid/NaCl microparticles were hollow and had a favourable hygroscopicity, and increased NaCl content and decreased organic acid content. Their size of the microparticles was 15.4-32.0μm and increased with NaCl concentration. The microparticles of acetic and lactic acid groups had a NaCl crystal size of 1-2 and 1-4μm, respectively. The NaCl crystals of acetic, lactic and citric acid group microparticles were distributed on the microparticle matrices, mostly on the microparticle surface and mainly on the inner walls of the microparticles walls, respectively. The acetic and lactic acid group microparticles were relatively smaller than general salt, with NaCl crystals distributed on the particle surfaces. Consequently, they were perceived as saltier than general salt and could potentially be regarded as a low-sodium salt for surface-salted foods. Copyright © 2017 Elsevier Ltd. All rights reserved.
β decay of Na32

NASA Astrophysics Data System (ADS)

Mattoon, C. M.; Sarazin, F.; Hackman, G.; Cunningham, E. S.; Austin, R. A. E.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Koopmans, K. A.; Leslie, J. R.; Phillips, A. A.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Svensson, C. E.; Waddington, J. C.; Walker, P. M.; Washbrook, B.; Zganjar, E.

2007-01-01

The β-decay of Na32 has been studied using β-γ coincidences. New transitions and levels are tentatively placed in the level scheme of Mg32 from an analysis of γ-γ and β-γ-γ coincidences. The observation of the indirect feeding of the 2321 keV state in Mg32 removes some restrictions previously placed on the spin assignment for this state. No evidence of a state at 2117 keV in Mg32 is found. Previously unobserved weak transitions up to 5.4 MeV were recorded but could not be placed in the decay scheme of Na32.
Effect of Na+ on surface fractal dimension of compacted bentonite

NASA Astrophysics Data System (ADS)

Xiang, G. S.; Xu, Y. F.; Jiang, H.

2015-05-01

Compacted Tsukinuno bentonite was immersed into NaCl solutions of different concentrations in oedometers, and the surface fractal dimension of bentonite-saline association was measured by nitrogen adsorption isotherms. The application of the Frenkel-Halsey-Hill equation and the Neimark thermodynamic method to nitrogen adsorption isotherms indicated that the surface roughness was greater for the bentonite-saline association. The surface fractal dimension of bentonite increased in the NaCl solution with low Na+ concentration, but decreased at high Na+ concentration. This process was accompanied by the same tendency in specific surface area and microporosity with the presence of Na+ coating in the clay particles.
Physical Biologycal Interactions Controlling Larvae Dispersion: Application to Regions in the Neighbourhood of the Estuaries of North Portugal

NASA Astrophysics Data System (ADS)

Almeida, Martinho Marta

Um modelo numerico tridimensional oceânico foi usado para estudar a influencia das condicoes fisicas na dispersao e recrutamento de larvas com migracao vertical diaria (MVD) activa na plataforma continental noroeste de Portugal. As primeiras simulacoes foram forcadas por mares e verificou-se que a interaccao entre MVD e correntes de mare nao e importante para o transporte de larvas na plataforma continental oeste portuguesa. O trabalho realizado com forcamento de mares incrementou o presente conhecimento da dinâmica da mare na regiao. A analise da variacao vertical dos parâmetros das elipses de mare mostra uma separacao clara entre os harmonicos diurnos e semi-diurnos, e entre a circulacao oceânica quase barotropica e as correntes com dependencia vertical na plataforma. Desprezando a interaccao entre MVD e as mares o proximo passo foi a construcao e validacao dum modelo realistico forcado por fluxos atmosfera-oceano, capaz de reproduzir as correntes dominantes, geradas pelo vento, na plataforma continental. Na configuracao criada a MVD das larvas foi simulada com quatro cenarios de distribuicao e migracao vertical. Foram feitas duas simulacoes, uma para o final do Inverno e outra para a Primavera, abrangendo os meses de Fevereiro a Abril e Abril a Junho de 2002. Estes periodos foram escolhidos pois exibem diferentes regimes de vento, nao favoravel e favoravel ao afloramento costeiro. Os resultados mostram que as particulas com MVD sofreram maior retencao na plataforma continental interna durante condicoes de afloramento do que em qualquer outra combinacao de cenario de migracao e regime de vento. Na costa noroeste da Peninsula Iberica, que nao exibe irregularidades topograficas que poderiam criar areas de concentracao e retencao, a MVD pode constituir um mecanismo importante para evitar a dispersao de larvas em direccao ao mar aberto. None
An improvement of LLNA:DA to assess the skin sensitization potential of chemicals.

PubMed

Zhang, Hongwei; Shi, Ying; Wang, Chao; Zhao, Kangfeng; Zhang, Shaoping; Wei, Lan; Dong, Li; Gu, Wen; Xu, Yongjun; Ruan, Hongjie; Zhi, Hong; Yang, Xiaoyan

2017-01-01

We developed a modified local lymph node assay based on ATP (LLNA:DA), termed the Two-Stage LLNA:DA, to further reduce the animal numbers in the identification of sensitizers. In the Two-Stage LLNA:DA procedure, 13 chemicals ranging from non-sensitizers to extreme sensitizers were selected. The first stage used reduced LLNA:DA (rLLNA:DA) to screen out sensitive chemicals. The second stage used LLNA:DA based on OECD 442 (A) to classify those potential sensitizers screened out in the first stage. In the first stage, the SIs of the methyl methacrylate, salicylic acid, methyl salicylate, ethyl salicylate, isopropanol and propanediol were below 1.8 and need not to be tested in the second step. Others continued to be tested by LLNA:DA. In the second stage, sodium lauryl sulphate and xylene were classified as weak sensitizers. a-hexyl cinnamic aldehyde and eugenol were moderate sensitizers. Benzalkonium chloride and glyoxal were strong sensitizers, and phthalic anhydride was an extreme sensitizer. The 9/9, 11/12, 10/11, and 8/13 (positive or negative only) categories of the Two-Stage LLNA:DA were consistent with those from the other methods (LLNA, LLNA:DA, GPMT/BT and HMT/HPTA), suggesting that Two-Stage LLNA:DA have a high coincidence rate with reported data. In conclusion, The Two-Stage LLNA:DA is in line with the "3R" rules, and can be a modification of LLNA:DA but needs more study.
Homogeneous synthesis of quaternized chitin in NaOH/urea aqueous solution as a potential gene vector.

PubMed

Peng, Na; Ai, Ziye; Fang, Zehong; Wang, Yanfeng; Xia, Zhiping; Zhong, Zibiao; Fan, Xiaoli; Ye, Qifa

2016-10-05

Water-soluble quaternized chitins (QCs) were homogeneously synthesized by reacting chitin with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) in 8wt% NaOH/4wt% urea aqueous solutions. The chemical structure and solution properties of the quaternized chitins were characterized by (1)H NMR, FT-IR, elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The results demonstrated that the water-soluble QCs, with a degree of substitution (DS) values of 0.27-0.54, could be obtained by varying the concentration of chitin, the molar ratio of CHPTAC to chitin unit, and the reaction time at room temperature (25°C). Two QCs (DS=0.36 and 0.54) were selected and studied as gene carriers. Agarose gel retardation assay revealed that both QCs could condense DNA efficiently when N/P ratio>3. The results of particle size and zeta potential indicated that both QCs had a good ability of condensing plasmid DNA into compact nanoparticles with the size of 100-200nm and zeta potential of +18 to +36mV. Compared to polyethylenimine (PEI, 25kDa), the QCs exhibited outstanding low cytotoxicity. Transfection efficiencies of the QCs/DNA complexes were measured using pGL-3 encoding luciferase as the foreign DNA, and the QCs/DNA complexes showed effective transfection efficiencies in 293T cells. These results revealed that the QCs prepared in NaOH/urea aqueous solutions could be used as promising non-viral gene carriers owing to their excellent characteristics. Copyright © 2016. Published by Elsevier Ltd.
Music and the nucleus accumbens.

PubMed

Mavridis, Ioannis N

2015-03-01

Music is a universal feature of human societies over time, mainly because it allows expression and regulation of strong emotions, thus influencing moods and evoking pleasure. The nucleus accumbens (NA), the most important pleasure center of the human brain (dominates the reward system), is the 'king of neurosciences' and dopamine (DA) can be rightfully considered as its 'crown' due to the fundamental role that this neurotransmitter plays in the brain's reward system. Purpose of this article was to review the existing literature regarding the relation between music and the NA. Studies have shown that reward value for music can be coded by activity levels in the NA, whose functional connectivity with auditory and frontal areas increases as a function of increasing musical reward. Listening to music strongly modulates activity in a network of mesolimbic structures involved in reward processing including the NA. The functional connectivity between brain regions mediating reward, autonomic and cognitive processing provides insight into understanding why listening to music is one of the most rewarding and pleasurable human experiences. Musical stimuli can significantly increase extracellular DA levels in the NA. NA DA and serotonin were found significantly higher in animals exposed to music. Finally, passive listening to unfamiliar although liked music showed activations in the NA.
Naïve Bayes classification in R.

PubMed

Zhang, Zhongheng

2016-06-01

Naïve Bayes classification is a kind of simple probabilistic classification methods based on Bayes' theorem with the assumption of independence between features. The model is trained on training dataset to make predictions by predict() function. This article introduces two functions naiveBayes() and train() for the performance of Naïve Bayes classification.
Campo de velocidade peculiar na teoria linear

NASA Astrophysics Data System (ADS)

Pires, N.

2003-08-01

Aglomerados e superaglomerados de galáxias são responsáveis pela chamada velocidade peculiar (movimentos relativos à expansão pura do universo) das galáxias. A amplitude destas perturbações depende da densidade de matéria do universo e do contraste de densidade no interior do volume onde está localizada a galáxia. Em 1980, Peebles introduziu o fator "f", que relaciona a amplitude das perturbações da velocidade com o campo gravitacional peculiar, no contexto da teoria linear. No presente trabalho obtemos uma solução geral analítica para o fator "f" de Peebles do campo de velocidades peculiares, em termos de funções hipergeométricas, válida para qualquer geometria do universo. Como um teste de nossa solução, os resultados encontrados originalmente por Peebles em 1980 e os resultados mais gerais encontrados por O. Lahav e colaboradores em 1991, são reobtidos.
Arrhenius Behavior of the Bulk Na-Ion Conductivity in Na3Sc2(PO4)3 Single Crystals Observed by Microcontact Impedance Spectroscopy.

PubMed

Rettenwander, Daniel; Redhammer, Günther J; Guin, Marie; Benisek, Artur; Krüger, Hannes; Guillon, Olivier; Wilkening, Martin; Tietz, Frank; Fleig, Jürgen

2018-03-13

NASICON-based solid electrolytes with exceptionally high Na-ion conductivities are considered to enable future all solid-state Na-ion battery technologies. Despite 40 years of research the interrelation between crystal structure and Na-ion conduction is still controversially discussed and far from being fully understood. In this study, microcontact impedance spectroscopy combined with single crystal X-ray diffraction, and differential scanning calorimetry is applied to tackle the question how bulk Na-ion conductivity σ bulk of sub-mm-sized flux grown Na 3 Sc 2 (PO 4 ) 3 (NSP) single crystals is influenced by supposed phase changes (α, β, and γ phase) discussed in literature. Although we found a smooth structural change at around 140 °C, which we assign to the β → γ phase transition, our conductivity data follow a single Arrhenius law from room temperature (RT) up to 220 °C. Obviously, the structural change, being mainly related to decreasing Na-ion ordering with increasing temperature, does not cause any jumps in Na-ion conductivity or any discontinuities in activation energies E a . Bulk ion dynamics in NSP have so far rarely been documented; here, under ambient conditions, σ bulk turned out to be as high as 3 × 10 -4 S cm -1 at RT ( E a, bulk = 0.39 eV) when directly measured with microcontacts for individual small single crystals.
Arrhenius Behavior of the Bulk Na-Ion Conductivity in Na3Sc2(PO4)3 Single Crystals Observed by Microcontact Impedance Spectroscopy

PubMed Central

2018-01-01

NASICON-based solid electrolytes with exceptionally high Na-ion conductivities are considered to enable future all solid-state Na-ion battery technologies. Despite 40 years of research the interrelation between crystal structure and Na-ion conduction is still controversially discussed and far from being fully understood. In this study, microcontact impedance spectroscopy combined with single crystal X-ray diffraction, and differential scanning calorimetry is applied to tackle the question how bulk Na-ion conductivity σbulk of sub-mm-sized flux grown Na3Sc2(PO4)3 (NSP) single crystals is influenced by supposed phase changes (α, β, and γ phase) discussed in literature. Although we found a smooth structural change at around 140 °C, which we assign to the β → γ phase transition, our conductivity data follow a single Arrhenius law from room temperature (RT) up to 220 °C. Obviously, the structural change, being mainly related to decreasing Na-ion ordering with increasing temperature, does not cause any jumps in Na-ion conductivity or any discontinuities in activation energies Ea. Bulk ion dynamics in NSP have so far rarely been documented; here, under ambient conditions, σbulk turned out to be as high as 3 × 10–4 S cm–1 at RT (Ea, bulk = 0.39 eV) when directly measured with microcontacts for individual small single crystals. PMID:29606799
Diffusion and the dynamics of displacive phase transitions in cryolite (Na3AlF6) and chiolite (Na5Al3F14): Multi-nuclear NMR studies

NASA Astrophysics Data System (ADS)

Spearing, Dane R.; Stebbins, Jonathan F.; Farnan, Ian

1994-10-01

Cryolite is a mixed-cation perovskite (Na2(NaAl)F6) which undergoes a monoclinic to orthorhombic displacive phase transition at ˜550° C. Chiolite (Na5Al3F14) is associated with cryolite in natural deposits, and consists of sheets of corner sharing [AlF6] octahedra interlayered with edge-sharing [NaF6] octahedra. Multi-nuclear NMR line shape and relaxation time (T1) studies were performed on cryolite and chiolite in order to gain a better understanding of the atomic motions associated with the phase transition in cryolite, and Na diffusion in cryolite and chiolite. 27Al, 23Na, and 19F static NMR spectra and T1's in cryolite suggest that oscillatory motions of the [AlF6] octahedra among four micro-twin and anti-phase domains in α-cryolite begin at least 150° C below the transition temperature and persist above it. Variable temperature 23Na MAS NMR further indicates diffusional exchange at a rate of at least 13 kHz between the Na sites by the time the transition temperature is reached. 27Al and 23Na T1's show the same behavior with increasing temperature, indicating the same relaxation mechanisms are responsible for both. The first order nature of the cryolite transition is apparent as a jump in the 23Na and 27Al T1's. Above the transition temperature, the T1's decrease slightly indicating that the motions responsible for the drop in T1, are still present above the transition, further supporting the dynamic nature of the high temperature phase of cryolite. Chiolite 23Na static spectra decrease in linewidth with increasing temperature, indicating increased Na diffusion, which is interpreted as occurring within the [NaF6] sheets in the chiolite structure, but not between the two different Na sites. 27Al and 23Na T1's show similar behavior as in cryolite, but there is no discontinuity due to a phase transition. 19F T1's are constant from room temperature to 150° C indicating no oscillatory motion of the [AlF6] octahedra in chiolite.
A dual-stage sodium thermal electrochemical converter (Na-TEC)

NASA Astrophysics Data System (ADS)

Limia, Alexander; Ha, Jong Min; Kottke, Peter; Gunawan, Andrey; Fedorov, Andrei G.; Lee, Seung Woo; Yee, Shannon K.

2017-12-01

The sodium thermal electrochemical converter (Na-TEC) is a heat engine that generates electricity through the isothermal expansion of sodium ions. The Na-TEC is a closed system that can theoretically achieve conversion efficiencies above 45% when operating between thermal reservoirs at 1150 K and 550 K. However, thermal designs have confined previous single-stage devices to thermal efficiencies below 20%. To mitigate some of these limitations, we consider dividing the isothermal expansion into two stages; one at the evaporator temperature (1150 K) and another at an intermediate temperature (650 K-1050 K). This dual-stage Na-TEC takes advantage of regeneration and reheating, and could be amenable to better thermal management. Herein, we demonstrate how the dual-stage device can improve the efficiency by up to 8% points over the best performing single-stage device. We also establish an application regime map for the single- and dual-stage Na-TEC in terms of the power density and the total thermal parasitic loss. Generally, a single-stage Na-TEC should be used for applications requiring high power densities, whereas a dual-stage Na-TEC should be used for applications requiring high efficiency.
The enhancement of neutral metal Na layer above thunderstorms

NASA Astrophysics Data System (ADS)

Yu, Bingkun; Xue, Xianghui; Lu, Gaopeng; Kuo, Chengling; Dou, Xiankang; Gao, Qi; Qie, Xiushu; Wu, Jianfei; Tang, Yihuan

2017-04-01

Na (sodium) exists as layers of atoms in the mesosphere/lower thermosphere (MLT) at altitudes between 80 and 105 km. It has lower ionization potential of 5.139 eV than atmospheric species, such as O2 (12.06 eV). Tropospheric thunderstorms affect the lower ionosphere and the ionospheric sporadic E (Es) at 100 km can also be influenced by lightning. The mechanism is expected to be associated with transient luminous events (TLE) as red sprites and gigantic jets at upper atmosphere. However, measurements of ionospheric electric fields of 20mV·m-1 above thunderstorms are less than estimated value (>48 0mV·m-1) to excite ionization in the lower ionosphere. We found an enhancement of Na layer above thunderstorms. The increase of Na density in the statistical result can be as much as 500 cm-3 and it will have an impact on ionospheric chemistry and modify the conductivity properties of the MLT region. The ionospheric observations made with two digisondes near the Na lidar, the thunderstorm model, ionosphere model, and Na chemistry model are all used to discuss the possible mechanisms responsible for the enhancement of Na layer after thunderstorms.
Myelin management by the 18.5–kDa and 21.5–kDa classic myelin basic protein isoforms

PubMed Central

Harauz, George; Boggs, Joan M.

2013-01-01

The classic myelin basic protein (MBP) splice isoforms range in nominal molecular mass from 14 to 21.5 kDa, and arise from the gene in the oligodendrocyte lineage (Golli) in maturing oligodendrocytes. The 18.5-kDa isoform that predominates in adult myelin adheres the cytosolic surfaces of oligodendrocyte membranes together, and forms a two-dimensional molecular sieve restricting protein diffusion into compact myelin. However, this protein has additional roles including cytoskeletal assembly and membrane extension, binding to SH3-domains, participation in Fyn-mediated signaling pathways, sequestration of phosphoinositides, and maintenance of calcium homeostasis. Of the diverse post-translational modifications of this isoform, phosphorylation is the most dynamic, and modulates 18.5-kDa MBP’s protein-membrane and protein-protein interactions, indicative of a rich repertoire of functions. In developing and mature myelin, phosphorylation can result in microdomain or even nuclear targeting of the protein, supporting the conclusion that 18.5-kDa MBP has significant roles beyond membrane adhesion. The full-length, early-developmental 21.5-kDa splice isoform is predominantly karyophilic due to a non-traditional P-Y nuclear localization signal, with effects such as promotion of oligodendrocyte proliferation. We discuss in vitro and recent in vivo evidence for multifunctionality of these classic basic proteins of myelin, and argue for a systematic evaluation of the temporal and spatial distributions of these protein isoforms, and their modified variants, during oligodendrocyte differentiation. PMID:23398367
Na+-H+ exchange activity in taste receptor cells.

PubMed

Vinnikova, Anna K; Alam, Rammy I; Malik, Shahbaz A; Ereso, Glenn L; Feldman, George M; McCarty, John M; Knepper, Mark A; Heck, Gerard L; DeSimone, John A; Lyall, Vijay

2004-03-01

mRNA for two Na(+)-H(+)-exchanger isoforms 1 and 3 (NHE-1 and NHE-3) was detected by RT-PCR in fungiform and circumvallate taste receptor cells (TRCs). Anti-NHE-1 antibody binding was localized to the basolateral membranes, and the anti-NHE-3 antibody was localized in the apical membranes of fungiform and circumvallate TRCs. In a subset of TRCs, NHE-3 immunoreactivity was also detected in the intracellular compartment. For functional studies, an isolated lingual epithelium containing a single fungiform papilla was mounted with apical and basolateral sides isolated and perfused with nominally CO(2)/HCO(3)(-)-free physiological media (pH 7.4). The TRCs were monitored for changes in intracellular pH (pH(i)) and Na(+) ([Na(+)](i)) using fluorescence ratio imaging. At constant external pH, 1) removal of basolateral Na(+) reversibly decreased pH(i) and [Na(+)](i); 2) HOE642, a specific blocker, and amiloride, a nonspecific blocker of basolateral NHE-1, attenuated the decrease in pH(i) and [Na(+)](i); 3) exposure of TRCs to basolateral NH(4)Cl or sodium acetate pulses induced transient decreases in pH(i) that recovered spontaneously to baseline; 4) pH(i) recovery was inhibited by basolateral amiloride, 5-(N-methyl-N-isobutyl)-amiloride (MIA), 5-(N-ethyl-N-isopropyl)-amiloride (EIPA), HOE642, and by Na(+) removal; 5) HOE642, MIA, EIPA, and amiloride inhibited pH(i) recovery with K(i) values of 0.23, 0.46, 0.84, and 29 microM, respectively; and 6) a decrease in apical or basolateral pH acidified TRC pH(i) and inhibited spontaneous pH(i) recovery. The results indicate the presence of a functional NHE-1 in the basolateral membranes of TRCs. We hypothesize that NHE-1 is involved in sour taste transduction since its activity is modulated during acid stimulation.
Is the Dark Side of the Moon Ever Illuminated by the Sun? (Breton Title: O Lado Escuro da Lua Nunca Apanha Sol?) El Lado Oscuro de la Luna Nunca Toma Sol?

NASA Astrophysics Data System (ADS)

Giovannini, Odilon; Pellenz, Daiana; Catelli, Francisco

2014-07-01

This work presents the elaboration of an answer to the question "Is the dark side of the moon ever illuminated by the sun?", in which issues related to the students' conceptions, how they arise, and the core elements that constitute a "good answer" are considered. These issues are initially elaborated from a literature review of the research in the field; then, and also based on this review, a didactic model that involves the relative motions of the Earth - Moon - Sun system is proposed. A description of the application of this model in a learning environment within middle school students is described. This work confirms the students' initial concepts described in the literature; on the other hand, the questions asked by students during the activity provide evidence that meaningful learning, at least to some degree, has occurred. Este trabalho apresenta a elaboração de uma resposta à pergunta "O lado escuro da Lua nunca apanha sol?" na qual são consideradas questões relacionadas às concepções iniciais dos alunos, de onde elas surgem e os elementos centrais que constituem uma "boa resposta". Essas questões são tratadas, inicialmente, a partir de uma revisão da literatura sobre pesquisas na área e, em seguida, também com base nessa revisão, um objeto modelo didático que envolve os movimentos relativos do sistema Terra - Lua - Sol é proposto. Uma descrição detalhada da aplicação deste modelo em um ambiente de aprendizagem com alunos do ensino fundamental é relatada. As concepções iniciais apresentadas na literatura se confirmam e os questionamentos feitos pelos estudantes por ocasião da aplicação do modelo fornecem indícios de que uma aprendizagem significativa, pelo menos em algum grau, ocorreu. El artículo se presenta el desarrollo de una respuesta a la pregunta "¿El lado oscuro de la luna nunca toma sol?", en la que se consideran algunas cuestiones vinculadas que se refieren a las concepciones iniciales de los estudiantes, dónde surgen
3 Tesla 23Na Magnetic Resonance Imaging During Acute Kidney Injury.

PubMed

Hammon, Matthias; Grossmann, Susan; Linz, Peter; Seuss, Hannes; Hammon, Rebecca; Rosenhauer, Daniela; Janka, Rolf; Cavallaro, Alexander; Luft, Friedrich C; Titze, Jens; Uder, Michael; Dahlmann, Anke

2017-09-01

Sodium and proton magnetic resonance imaging ( 23 Na/ 1 H-MRI) have shown that muscle and skin can store Na + without water. In chronic renal failure and in heart failure, Na + mobilization occurs, but is variable depending on age, dialysis vintage, and other features. Na + storage depots have not been studied in patients with acute kidney injury (AKI). We studied 7 patients with AKI (mean age: 51.7 years; range: 25-84) and 14 age-matched and gender-matched healthy controls. All underwent 23 Na/ 1 H-MRI at the calf. Patients were studied before and after acute hemodialysis therapy within 5-6 days. The 23 Na-MRI produced grayscale images containing Na + phantoms, which served to quantify Na + contents. A fat-suppressed inversion recovery sequence was used to quantify H 2 O content. Plasma Na + levels did not change. Mean Na + contents in muscle and skin did not significantly change following four to five cycles of hemodialysis treatment (before therapy: 32.7 ± 6.9 and 44.2 ± 13.5 mmol/L, respectively; after dialysis: 31.7 ± 10.2 and 42.8 ± 11.8 mmol/L, respectively; P > .05). Water content measurements did not differ significantly before and after hemodialysis in muscle and skin (P > .05). Na + contents in calf muscle and skin of patients before hemodialysis were significantly higher than in healthy subjects (16.6 ± 2.1 and 17.9 ± 3.2) and remained significantly elevated after hemodialysis. Na + in muscle and skin accumulates in patients with AKI and, in contrast to patients receiving chronic hemodialysis and those with acute heart failure, is not mobilized with hemodialysis within 5-6 days. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.
Na+ extrusion from the cytosol and tissue-specific Na+ sequestration in roots confer differential salt stress tolerance between durum and bread wheat.

PubMed

Wu, Honghong; Shabala, Lana; Azzarello, Elisa; Huang, Yuqing; Pandolfi, Camilla; Su, Nana; Wu, Qi; Cai, Shengguan; Bazihizina, Nadia; Wang, Lu; Zhou, Meixue; Mancuso, Stefano; Chen, Zhonghua; Shabala, Sergey

2018-06-11

The progress in plant breeding for salinity stress tolerance is handicapped by the lack of understanding of the specificity of salt stress signalling and adaptation at the cellular and tissue levels. In this study, we used electrophysiological, fluorescence imaging, and real-time quantitative PCR tools to elucidate the essentiality of the cytosolic Na+ extrusion in functionally different root zones (elongation, meristem, and mature) in a large number of bread and durum wheat accessions. We show that the difference in the root's ability for vacuolar Na+ sequestration in the mature zone may explain differential salinity stress tolerance between salt-sensitive durum and salt-tolerant bread wheat species. Bread wheat genotypes also had on average 30% higher capacity for net Na+ efflux from the root elongation zone, providing the first direct evidence for the essentiality of the root salt exclusion trait at the cellular level. At the same time, cytosolic Na+ accumulation in the root meristem was significantly higher in bread wheat, leading to the suggestion that this tissue may harbour a putative salt sensor. This hypothesis was then tested by investigating patterns of Na+ distribution and the relative expression level of several key genes related to Na+ transport in leaves in plants with intact roots and in those in which the root meristems were removed. We show that tampering with this sensing mechanism has resulted in a salt-sensitive phenotype, largely due to compromising the plant's ability to sequester Na+ in mesophyll cell vacuoles. The implications of these findings for plant breeding for salinity stress tolerance are discussed.

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