882 research outputs found

    A Multistage Method for SCMA Codebook Design Based on MDS Codes

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    Sparse Code Multiple Access (SCMA) has been recently proposed for the future generation of wireless communication standards. SCMA system design involves specifying several parameters. In order to simplify the procedure, most works consider a multistage design approach. Two main stages are usually emphasized in these methods: sparse signatures design (equivalently, resource allocation) and codebook design. In this paper, we present a novel SCMA codebook design method. The proposed method considers SCMA codebooks structured with an underlying vector space obtained from classical block codes. In particular, when using maximum distance separable (MDS) codes, our proposed design provides maximum signal-space diversity with a relatively small alphabet. The use of small alphabets also helps to maintain desired properties in the codebooks, such as low peak-to-average power ratio and low-complexity detection.Comment: Submitted to IEEE Wireless Communication Letter

    The new nitric oxide donor cyclohexane nitrate induces vasorelaxation, hypotension, and antihypertensive effects via NO/cGMP/PKG pathway

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    We investigated the cardiovascular effects induced by the nitric oxide donor Cyclohexane Nitrate (HEX). Vasodilatation, NO release and the effects of acute or sub-chronic treatment with HEX on cardiovascular parameters were evaluated. HEX induced endothelium-independent vasodilatation (Maximum effect- [efficacy, ME] = 100.4±4.1%; potency [pD2] = 5.1±0.1). Relaxation was attenuated by scavenging nitric oxide (ME = 44.9±9.4% vs. 100.4±4.1%) or by inhibiting the soluble guanylyl cyclase (ME = 38.5±9.7% vs. 100.4±4.1%). In addition, pD2 was decreased after non-selective blockade of K+ channels (pD2 = 3.6±0.1 vs. 5.1±0.1) or by inhibiting KATP channels (pD2 = 4.3±0.1 vs. 5.1±0.1). HEX increased NO levels in mesenteric arteries (33.2±2.3 au vs. 10.7±0.2 au, p<0.0001). Intravenous acute administration of HEX (1-20 mg/kg) induced hypotension and bradycardia in normotensive and hypertensive rats. Furthermore, starting at six weeks after the induction of 2K1C hypertension, oral treatment with the HEX (10 mg/Kg/day) for seven days reduced blood pressure in hypertensive animals (134±6 vs 170±4 mmHg, respectively). Our data demonstrate that HEX is a NO donor able to produce vasodilatation via NO/cGMP/PKG pathway and activation of the ATP-sensitive K+ channels. Furthermore, HEX acutely reduces blood pressure and heart rate as well as produces antihypertensive effect in renovascular hypertensive rats

    Determination of Escitalopram in Human Plasma by High Performance Liquid Chromatography-Tandem Mass Spectrometry

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    A rapid (3.0 min) and sensitive (LLOQ 0.5 ng/mL) analytical method for the quantitation of Escitalopram (ETP) in human plasma is described. The method is based on High-Performance Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) using paroxetine as internal standard (I.S.). Sample preparation involved precipitation extraction with acetonitrile. The chromatographic separation was achieved on a ACE C18 (125 x 4,6 mm) reversed-phase column and a mobile phase containing acetonitrile/water (60:50 v/v, add 0.2 % formic acid), in isocratic conditions. The target analytes were transferred into a triple quadrupole mass spectrometer equipped with an electrospray ionization source for mass detection. The ion transitions selected for MRM detection were: m/z 325.2 > 109.2 and 330.0 > 192.0 for ETP and I.S., respectively. The assay was linear in the concentration range of 0.5-50 ng/mL. The mean recovery for ETP was 97.69 %. Intra- and inter-day precision (R.S.D.) were < 10.5 % and <8.2 %, respectively and the accuracy (R.E.) was in the range ± 12.23 %. The method was successfully applied to a single oral dose pharmacokinetics study in 28 healthy Brazilian human volunteers.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Contribution of the institutions in the Northern region of Brazil to the development of plant cultivars and their impact on agriculture

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    This paper describes the development of breeding programs in northern Brazil and their main impacts on agriculture. Their contribution to the breeding of the species palm oil, acai fruit, cacao, cupuaçu, guarana, tomato, camu-camu, cocona, peach palm, and rubber was laid out in detail. Advances in breeding programs of institutions such as Embrapa, Ceplac, Inpa, and Universities require investments in infrastructure and in human and financial resources to ensure continuity and efficiency in economic, social and environmental gains. The improvement of native species, the main focus of the breeding programs of the institutions in the Northern region of Brazil, is a form of exploiting the Amazonian biodiversity for the benefit of society. Therefore, policies to foster research institutions should be a subject of deliberation and action of the scientific and technological community in Brazil

    Incidence and risk factors for Preeclampsia in a cohort of healthy nulliparous pregnant women: a nested case-control study

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    The objective of this study is to determine the incidence, socio-demographic and clinical risk factors for preeclampsia and associated maternal and perinatal adverse outcomes. This is a nested case-control derived from the multicentre cohort study Preterm SAMBA, in five different centres in Brazil, with nulliparous healthy pregnant women. Clinical data were prospectively collected, and risk factors were assessed comparatively between PE cases and controls using risk ratio (RR) (95% CI) plus multivariate analysis. Complete data were available for 1,165 participants. The incidence of preeclampsia was 7.5%. Body mass index determined at the first medical visit and diastolic blood pressure over 75 mmHg at 20 weeks of gestation were independently associated with the occurrence of preeclampsia. Women with preeclampsia sustained a higher incidence of adverse maternal outcomes, including C-section (3.5 fold), preterm birth below 34 weeks of gestation (3.9 fold) and hospital stay longer than 5 days (5.8 fold) than controls. They also had worse perinatal outcomes, including lower birthweight (a mean 379 g lower), small for gestational age babies (RR 2.45 [1.52-3.95]), 5-minute Apgar score less than 7 (RR 2.11 [1.03-4.29]), NICU admission (RR 3.34 [1.61-6.9]) and Neonatal Near Miss (3.65 [1.78-7.49]). Weight gain rate per week, obesity and diastolic blood pressure equal to or higher than 75 mmHg at 20 weeks of gestation were shown to be associated with preeclampsia. Preeclampsia also led to a higher number of C-sections and prolonged hospital admission, in addition to worse neonatal outcomes9CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ401636/2013-5Bill and Melinda Gates FoundationGates Foundation [OPP1107597]; CNPqNational Council for Scientific and Technological Development (CNPq) [401636/2013-5
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