2,045 research outputs found

    A New Approach to the Design of CMOS Inductorless Common-gate Low-noise Amplifiers

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    This work proposes a new approach to design a simple and effective LNA reaching very competitive results in 1.2V 65-nm standard CMOS technology. The proposed design uses a transconductance enhancement technique to achieve 2.3 dB of noise figure at the 5 GHz band. The paper exposes the advantages of a reduced number of devices in the circuit and analyses the topology. Simulations with complete technology models and statistical analysis are presented for more precise results

    Dynamical phase transition for a quantum particle source

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    We analyze the time evolution describing a quantum source for noninteracting particles, either bosons or fermions. The growth behaviour of the particle number (trace of the density matrix) is investigated, leading to spectral criteria for sublinear or linear growth in the fermionic case, but also establishing the possibility of exponential growth for bosons. We further study the local convergence of the density matrix in the long time limit and prove the semiclassical limit.Comment: 24 pages; In the new version, we added several references concerning open quantum systems and present an extended result on linear particle production in the fermionic cas

    A Fully-Integrated CMOS LDO Regulator for Battery-Operated On-Chip Measurement Systems

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    This paper presents a fully-integrated 0.18 mu m CMOS low drop-out (LDO) regulator designed to drive on-chip low power frontend sensor nodes. The proposed LDO is based on a simple telescopic amplifier stage with internal cascode compensation driving a PMOS pass-device, providing a high precision 1.8 V output voltage for input voltages from 3.6 V to 1.92 V up to a 50 mA load current with only 22 mu A quiescent current. Line and load regulation are respectively better than 0.017 mV/V and 0.003 mV/mA, while recovery times are below 4 mu s over a (-40 degrees C, 120 degrees C) temperature span

    The non-commutative Landau problem

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    The Landau problem is discussed in two similar but still different non-commutative frameworks. The ``standard'' one, where the coupling to the gauge field is achieved using Poisson brackets, yields all Landau levels. The ``exotic'' approach, where the coupling to the gauge field is achieved using the symplectic structure, only yields lowest-Landau level states, as advocated by Peierls and used in the description of the ground states of the Fractional Quantum Hall Effect. The same reduced model also describes vortex dynamics in a superfluid 4{}^4He film. Remarkably, the spectrum depends crucially on the quantization scheme. The system is symmetric w. r. t. area-preserving diffeomorphisms.Comment: Published with shortened title as Ann. Phys. (N. Y.) 299, pp. 128-140 (2002) 14 pages, LaTex, no figure

    Gemcitabine-induced haemolytic uremic syndrome, although infrequent, can it be prevented: A case report and review of literatureN

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    Gemcitabine is an antineoplastic used to treat several malignancies including pancreatic cancer. Its toxicity profile is well known with myelotoxicity, increased vascular permeability and peripheral oedema as most frequent adverse events. However, several cases of acute renal failure have been reported and haemolytic uremic syndrome (HUS) seems to be the underlying process. The cause of HUS remains unknown but its consequences can be lethal. Therefore, a high grade of suspicion is crucial to diagnose it and promptly treat it. This hopefully will reduce its morbidity. HUS is characterized by progressive renal failure associated with microangiopathic haemolytic anaemia and thrombocytopenia. The primary event is damage to endothelial cells and thrombotic microangiopathy (TMA) is the histopathological lesion. TMA affects mainly renal microvasculature. However, some cases evolve with central nervous or cardiovascular systems involvement. We present here a case of gemcitabine-induced HUS, with renal and cardiovascular system affected at the time of diagnosis which to our knowledge this is the first time of such case to be reported

    The Structure of TGBC_C Phases

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    We study the transition from the cholesteric phase to two TGBC_C phases near the upper critical twist kc2k_{c2}: the Renn-Lubensky TGBC_C phase, with layer normal rotating in a plane perpendicular to the pitch axis, and the Bordeaux TGBC_C phase, with the layer normal rotating on a cone parallel to the pitch axis. We calculate properties, including order-parameter profiles, of both phases.Comment: 4 pages, 4 figures, Submitted to Physical Review E, Rapid Communications, September 5, 2003; Revised manuscript (to the paper submitted on March 18, 2003, cond-mat/0303365)that includes an important missing reference and presents an improved analysis of a generalized mode

    Galilean symmetry in noncommutative field theory

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    When the interaction potential is suitably reordered, the Moyal field theory admits two types of Galilean symmetries, namely the conventional mass-parameter-centrally-extended one with commuting boosts, but also the two-fold centrally extended ``exotic'' Galilean symmetry, where the commutator of the boosts yields the noncommutative parameter. In the free case, one gets an ``exotic'' two-parameter central extension of the Schroedinger group. The conformal symmetry is, however, broken by the interaction.Comment: Corrected version. Further remarks and references added. LaTex, 8 pages, no figure

    Combined effect of salinity and led lights on the yield and quality of purslane (Portulaca oleracea l.) microgreens

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    The present work aims to explore the potential to improve quality of purslane microgreens by combining water salinity and LED lighting during their cultivation. Purslane plants were grown in a growth chamber with light insulated compartments, under different lighting sources on a 16 h d-1 photoperiod\u2014fluorescent lamps (FL) and two LED treatments, including a red and blue (RB)) spectrum and a red, blue and far red (RB+IR) LED lights spectrum\u2014while providing all of them a light intensity of 150 umol m-2 s-1. Plants were exposed to two salinity treatments, by adding 0 or 80 mM NaCl. Biomass, cation and anions, total phenolics (TPC) and flavonoids content (TFC), total antioxidant capacity (TAC), total chlorophylls (Chl) and carotenoids content (Car) and fatty acids were determined. The results showed that yield was increased by 21% both in RB and RB+FR lights compared to FL and in salinity compared to non-salinity conditions. The nitrate content was reduced by 81% and 91% when microgreens were grown under RB and RB+FR, respectively, as compared to FL light, and by 9.5% under saline conditions as compared with non-salinity conditions. The lowest oxalate contents were obtained with the combinations of RB or RB+FR lighting and salinity. The content of Cl and Na in the leaves were also reduced when microgreens were grown under RB and RB+FR lights under saline conditions. Microgreens grown under RB light reached the highest TPC, while salinity reduced TFC, Chl and Car. Finally, the fatty acid content was not affected by light or salinity, but these factors slightly influenced their composition. It is concluded that the use of RB and RB+FR lights in saline conditions is of potential use in purslane microgreens production, since it improves the yield and quality of the product, reducing the content of anti-nutritional compounds

    Losartan metabolite EXP3179 blocks NADPH oxidase-mediated superoxide production by inhibiting protein kinase C: potential clinical implications in hypertension

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    Oxidative stress plays a critical role in the pathogenesis of hypertension. The NADPH oxidase constitutes a major source of superoxide anion in phagocytic cells, and its activation is associated with matrix metalloproteinase (MMP)-9 secretion by these cells. We investigated the effects of the angiotensin II type 1 receptor antagonist losartan and its metabolites (EXP3174 and EXP3179) on NADPH oxidase activity and MMP-9 secretion in human phagocytic cells. EXP3179, but not losartan and EXP3174, dose-dependently inhibited (P<0.05) phorbol myristate acetate and insulin-stimulated NADPH oxidase activity. EXP3179 also inhibited phorbol myristate acetate-induced NADPH oxidase in endothelial cells. In addition, EXP3179 inhibited (P<0.05) both phorbol myristate acetate-stimulated p47phox translocation from cytosol to membranes and protein kinase C activity. Affinity experiments and enzymatic assays confirmed that EXP3179 inhibited several protein kinase C isoforms. EXP3179 also inhibited (P<0.05) phorbol myristate acetate-stimulated MMP-9 secretion. In a study performed in 153 hypertensive patients, phagocytic NADPH oxidase activity was lower (P<0.05) in losartan-treated compared with untreated patients and in patients treated with other angiotensin II type 1 receptor antagonists or with angiotensin-converting enzyme inhibitors. Plasma levels of MMP-9 were lower (P<0.05) in losartan-treated hypertensives compared with the other group of patients. Thus, EXP3179 acts as a blocker of the NADPH oxidase in phagocytic cells by a potential mechanism that targets the protein kinase C signaling pathway. This effect can be involved in reduced MMP-9 secretion by these cells. It is proposed that the EXP3179 metabolite may confer to losartan the specific capacity to reduce oxidative stress mediated by phagocytic cells in hypertensive patients
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