248 research outputs found

    [2,6-Bis(dimethyl­amino­meth­yl)phen­yl]selenium bromide monohydrate

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    In the title hydrated molecular salt, C12H19N2Se+·Br−·H2O, the two independent bromide anions lie on a twofold rotation axis. Strong intra­molecular N→Se inter­actions [2.185 (3) and 2.181 (3) Å] are established by both N atoms of the organic group in the cation, in trans positions to each other, with an N—Se—N angle of 161.6 (1)°, resulting in a T-shaped (C,N,N′)Se core. In the crystal, dimeric associations are formed by Br⋯Se [3.662 (2) Å] and Br⋯H inter­actions [2.56 (6) and 2.63 (7) Å] involving two bromide anions, two cations and two water mol­ecules

    Where did all the irrigators go? Trends in irrigation and demographics in Kansas

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    Presented at the 2006 Central Plains irrigation conference on February 21-22 in Colby, Kansas.The 2000 United States Census indicated that Kansas had grown by 8.51 percent in population since 1990, compared to the national average growth rate of 13.15 percent. Only nine (9) of 105 counties in Kansas experienced growth equal to or greater than the national average growth rate. From 2000-2004 only 8 counties grew at or above the national average growth rate. In 1990, Kansans were 1.00 percent of the U.S. population, in 2004 only 0.94% of the population. The 2004 population estimates had 56 of 105 counties in Kansas declining in population since 2000. Of the 54 counties overlying the High Plains aquifer, only three (3) counties had equal or greater growth than the national average. In addition the census also indicated a cultural transition as many counties experienced domestic out-migration and foreign immigration. Agricultural Census data document a 5.26 percent decrease in the total market value of agricultural products from 1997 to 2002, while the total number of farms increased 4.58 percent in Kansas during the same period. The number of Irrigated farms decreased by 3.58 percent with total irrigated acres declining by only 1.07 percent to 2.678 million acres over the same five year period. Total acreage in crop production declined 1.59 percent, while the market value of crops sold decreasing 24.9% from 3.22billionin1997to3.22 billion in 1997 to 2.42 billion in 2002. Since 1990, irrigation technology has dramatically changed to more efficient low pressure pivot and SDI (subsurface drip irrigation) systems. With more efficient water use, irrigators have been able to grow significantly more corn and other water intensive crops. Given the 3.5 percent decrease in the number of irrigated farms since 1997, the resulting 1.08 percent decline in irrigated acres indicates increased acreage efficiency by remaining irrigators. This presentation intends to demonstrate spatial and temporal trends in irrigation and demographics for Kansas, with focus on the 54 counties overlying the High Plains Aquifer

    Spontaneous appearance of de novo intracranial arteriovenous malformation in hepatic cirrhosis

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    BACKGROUND Intracranial arteriovenous malformations (AVMs) are rare lesions that can be congenital or acquired in early childhood, with fatal outcome in approximately 30% of cases. De novo formation during adulthood without established predisposing vascular pathology or previous brain insult is even less frequent. CASE DESCRIPTION We present a case of de novo brain AVM in an alcoholic Child-B cirrhosis setting. Thirty previously reported cases presented de novo AVM in patients of all ages that had another previous brain pathology or insult, such as AVM resection. Seventeen of those cases occurred in adult patients, with only 2 showing no significant predisposing factor. The present pathophysiological review covers and completes Mullan's hemodynamic "two-hit" model, associating probable thrombotic predisposition to AVM with brain insult triggering a later stage based on angiogenic stimuli. CONCLUSIONS This case report and literature review renews previously discussed hemodynamic theories and contributes to a fuller understanding of the pathogenesis and progression of AVM. We postulate a causal link between hepatopathy and de novo AVM, which should be strengthened and interpreted based on recent genetic data and future prospective studies

    Electrical resistivity image of the South Atlantic continental margin derived from onshore and offshore magnetotelluric data

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    We present a deep electrical resistivity image from the passive continental margin in Namibia. The approximately 700 km long magnetotelluric profile follows the Walvis Ridge offshore, continues onshore across the Kaoko Mobile Belt and reaches onto the Congo Craton. Two-dimensional inversion reveals moderately resistive material offshore, atypically low for oceanic lithosphere, reaching depths of 15–20 km. Such moderate resistivities are consistent with seismic P wave velocity models, which suggest up to 35 km thick crust. The Neoproterozoic rocks of the Kaoko Mobile Belt are resistive, but NNW-striking major shear-zones are imaged as subvertical, conductive structures in the upper and middle crust. Since the geophysical imprint of the shear zones is intact, opening of the South Atlantic in the Cretaceous did not alter the middle crust. The transition into the cratonic region coincides with a deepening of the high-resistive material to depths of more than 60 km

    Controlled-source electromagnetic and seismic delineation of sub-seafloor fluid flow structures in a gas hydrate province, offshore Norway

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    Deep sea pockmarks underlain by chimney-like or pipe structures that contain methane hydrate are abundant along the Norwegian continental margin. In such hydrate provinces the interaction between hydrate formation and fluid flow has significance for benthic ecosystems and possibly climate change. The Nyegga region, situated on the western Norwegian continental slope, is characterized by an extensive pockmark field known to accommodate substantial methane gas hydrate deposits. The aim of this study is to detect and delineate both the gas hydrate and free gas reservoirs at one of Nyegga's pockmarks. In 2012, a marine controlled-source electromagnetic (CSEM) survey was performed at a pockmark in this region, where high-resolution three-dimensional seismic data were previously collected in 2006. Two-dimensional CSEM inversions were computed using the data acquired by ocean bottom electrical field receivers. Our results, derived from unconstrained and seismically constrained CSEM inversions, suggest the presence of two distinctive resistivity anomalies beneath the pockmark: a shallow vertical anomaly at the underlying pipe structure, likely due to gas hydrate accumulation, and a laterally extensive anomaly attributed to a free gas zone below the base of the gas hydrate stability zone. This work contributes to a robust characterization of gas hydrate deposits within sub-seafloor fluid flow pipe structures

    Asymmetric emission of high energy electrons in the two-dimensional hydrodynamic expansion of large xenon clusters irradiated by intense laser fields

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    Energy spectra and angular distributions have been measured of electrons that are emitted upon disassembly of Xe150000Xe_{150000} following irradiation by intense (10151016^{15}-10^{16} W cm2^{-2}) laser pulses whose durations are varied over the 100-2200 fs range. The cluster explosion dynamics occur in the hydrodynamic regime. Electron emission is found to be unexpectedly asymmetric and exhibits a resonance when the laser pulse duration is \sim1 ps. These results are rationalized by extending the hydrodynamic model to also take into account the force that the light field exerts on the polarization charge that is induced on surface of the cluster. We show that the magnitude of this electrostrictive force is comparable to those of Coulombic and the hydrodynamic forces, and it exhibits resonance behavior. Contrary to earlier understanding, we find that low-energy electrons are connected to the resonance in energy absorption by the cluster. The high-energy electrons seem to be produced by a mechanism that is not so strongly influenced by the resonance.Comment: 1 Revtex file, 8 figs. in eps forma

    Novel (Hetero)arylalkenyl propargylamine compounds are protective in toxin-induced models of Parkinson's disease

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    Background: Mitochondrial dysfunction, oxidative stress and their interplay are core pathological features of Parkinson's disease. In dopaminergic neurons, monoamines and their metabolites provide an additional source of reactive free radicals during their breakdown by monoamine oxidase or auto-oxidation. Moreover, mitochondrial dysfunction and oxidative stress have a supraadditive impact on the pathological, cytoplasmic accumulation of dopamine and its subsequent release. Here we report the effects of a novel series of potent and selective MAO-B inhibitory (hetero)arylalkenylpropargylamine compounds having protective properties against the supraadditive effect of mitochondrial dysfunction and oxidative stress. Results: The (hetero)arylalkenylpropargylamines were tested in vitro, on acute rat striatal slices, pretreated with the complex I inhibitor rotenone and in vivo, using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced acute, subchronic, and chronic experimental models of Parkinson's disease in mice. The compounds exhibited consistent protective effects against i) in vitro oxidative stress induced pathological dopamine release and the formation of toxic dopamine quinone in the rat striatum and rescued tyrosine hydroxylase positive neurons in the substantia nigra after rotenone treatment; ii) in vivo MPTP-induced striatal dopamine depletion and motor dysfunction in mice using acute and subchronic, delayed application protocols. One compound (SZV558) was also examined and proved to be protective in a chronic mouse model of MPTP plus probenecid (MPTPp) administration, which induces a progressive loss of nigrostriatal dopaminergic neurons. Conclusions: Simultaneous inhibition of MAO-B and oxidative stress induced pathological dopamine release by the novel propargylamines is protective in animal models and seems a plausible strategy to combat Parkinson's disease

    Expressão de proteínas SMAD, mediadores da sinalização de TGF-beta/activina, em tecidos de tiroide humana

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    OBJECTIVE: To investigate the expression of SMAD proteins in human thyroid tissues since the inactivation of TGF-β/activin signaling components is reported in several types of cancer. Phosphorylated SMAD 2 and SMAD3 (pSMAD2/3) associated with the SMAD4 induce the signal transduction generated by TGF-β and activin, while SMAD7 inhibits this intracellular signaling. Although TGF-β and activin exert antiproliferative roles in thyroid follicular cells, thyroid tumors express high levels of these proteins. MATERIALS AND METHODS: The protein expression of SMADs was evaluated in multinodular goiter, follicular adenoma, papillary and follicular carcinomas by immunohistochemistry. RESULTS: The expression of pSMAD2/3, SMAD4 and SMAD7 was observed in both benign and malignant thyroid tumors. Although pSMAD2/3, SMAD4 and SMAD7 exhibited high cytoplasmic staining in carcinomas, the nuclear staining of pSMAD2/3 was not different between benign and malignant lesions. CONCLUSIONS: The finding of SMADs expression in thyroid cells and the presence of pSMAD2/3 and SMAD4 proteins in the nucleus of tumor cells indicates propagation of TGF-β/activin signaling. However, the high expression of the inhibitory SMAD7, mostly in malignant tumors, could contribute to the attenuation of the SMADs antiproliferative signaling in thyroid carcinomas.OBJETIVO: Investigar a expressão de proteínas SMAD em tecidos de tiroide humana desde que a inativação dos componentes da sinalização de TGF-β/activina é relatada em diversos tipos de câncer. SMAD 2 e SMAD3 fosforilados (pSMAD2/3) associados com SMAD4 induzem a transmissão do sinal gerado por TGF-β e activina, enquanto SMAD7 inibe essa sinalização intracelular. Embora TGF-β e activina exerçam efeitos antiproliferativos nas células foliculares da tiroide, tumores de tiroide expressam altos níveis dessas proteínas. MATERIAIS E MÉTODOS: A expressão proteica de SMADs foi avaliada em bócio multinodular, adenoma folicular, carcinomas papilífero e folicular por imuno-histoquímica. RESULTADOS: A expressão de pSMAD2/3, SMAD4 e SMAD7 foi observada tanto em tumores benignos como malignos da tiroide. Embora pSMAD2/3, SMAD4 e SMAD7 exibissem alta positividade citoplasmática em carcinomas, a positividade nuclear de pSMAD2/3 não foi diferente entre lesões benignas e malignas da tiroide. CONCLUSÕES: O achado da expressão de SMADs em células tiroidianas e a presença das proteínas pSMAD2/3 e SMAD4 no núcleo de células tumorais indicam propagação da sinalização TGF-β/activina. Contudo, a alta expressão de SMAD7 inibitório, principalmente em tumores malignos, poderia contribuir para atenuação da sinalização antiproliferativa de SMADs em carcinomas de tiroide.(FAPESP) São Paulo Research Foundation(CAPES) Coordination for the Improvement of Higher Education PersonnelCNPq National Counsel of Technological and Scientific Developmen

    Role of surface roughness in hard x-ray emission from femtosecond laser produced copper plasmas

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    The hard x-ray emission in the energy range of 30-300 keV from copper plasmas produced by 100 fs, 806 nm laser pulses at intensities in the range of 10151016^{15}-10^{16} W cm2^{-2} is investigated. We demonstrate that surface roughness of the targets overrides the role of polarization state in the coupling of light to the plasma. We further show that surface roughness has a significant role in enhancing the x-ray emission in the above mentioned energy range.Comment: 5 pages, 4 figures, to appear in Phys. Rev.
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