214 research outputs found
Marine Applications for a Promising New Spectroscopic Method
International Workshop: Applications and Perspectives of Cavity Enhanced Optical Detection Techniques in Ocean Sciences; Kiel, Germany, 20â21 April 201
Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants
Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17-2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3ÎČ-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant.Fil: Cassan, Fabricio Dario. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas FisicoquĂmicas y Naturales. CĂĄtedra de FisiologĂa Vegetal; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba; ArgentinaFil: Bottini, Ambrosio Ruben. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas FisicoquĂmicas y Naturales. CĂĄtedra de FisiologĂa Vegetal; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba; ArgentinaFil: Schneider, Gernot. Leibniz Institut fuÌr Pflanzenbiochemi; AlemaniaFil: Piccoli, Patricia NoemĂ. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas FisicoquĂmicas y Naturales; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba; Argentin
On sets of eigenvalues of matrices with prescribed row sums and prescribed graph
Motivated by a work of Boros, Brualdi, Crama and Hoffman, we consider the
sets of (i) possible Perron roots of nonnegative matrices with prescribed row
sums and associated graph, and (ii) possible eigenvalues of complex matrices
with prescribed associated graph and row sums of the moduli of their entries.
To characterize the set of Perron roots or possible eigenvalues of matrices in
these classes we introduce, following an idea of Al'pin, Elsner and van den
Driessche, the concept of row uniform matrix, which is a nonnegative matrix
where all nonzero entries in every row are equal. Furthermore, we completely
characterize the sets of possible Perron roots of the class of nonnegative
matrices and the set of possible eigenvalues of the class of complex matrices
under study. Extending known results to the reducible case, we derive new sharp
bounds on the set of eigenvalues or Perron roots of matrices when the only
information available is the graph of the matrix and the row sums of the moduli
of its entries. In the last section of the paper a new constructive proof of
the Camion-Hoffman theorem is given.Comment: 22 page
Efficacy and safety outcomes for acute ischemic stroke patients treated with intravenous infusion of tirofiban after emergent carotid artery stenting
Introduction
Emergent stenting of the extracranial internal carotid artery (ICA) in stroke patients requires antiplatelet therapy to prevent in-stent thrombosis with a higher risk of intracranial haemorrhage.
Aim of the Study
Assess the efficacy and safety of emergent carotid stenting with intravenous tirofiban in acute ischemic stroke patients.
Methods
Primary endpoint: symptomatic hemorrhage. Secondary endpoints: 90-day functional outcome and mortality.
Results
Of the 62 patients, 21 (34%) received tirofiban as a single antiplatelet, and 41 (66%) received combined therapy. Premedication with anticoagulants and antiplatelets was significantly more frequent in the tirofiban-only group. The rate of symptomatic haemorrhage was significantly lower in the tirofiban-only group than in the combined group (4.8% vs. 27%, pâŻ=â0.046). The patients with tirofiban alone had a significantly better functional outcome at day 90 than the combined group (52% vs. 24%, pâŻ=â0.028). Mortality was equal (24%) in both groups. Pre-interventional NIHSS score (pâŻ=â0.003), significant blood pressure fluctuations (pâŻ=â0.012), tandem occlusion (pâŻ=â0.023), and thrombolysis (pâŻ=â0.044) showed relevant influence on the rate of symptomatic hemorrhage in the entire patient cohort.
Conclusions
A single antiplatelet therapy with tirofiban regardless of the premedication may improve the functional outcome in patients with stroke due to acute extracranial carotid lesion and emergent carotid stenting with lower rates of serious intracranial haemorrhage.
For patients with high pre-interventional NIHSS score, tandem occlusion and after pre-interventional thrombolysis, caution is advised. Additionally, strict blood pressure monitoring should be conducted during the first 72âŻh after intervention
Comparison of safety and efficacy after emergency stenting in patients exhibiting intracranial atherosclerotic stenosis associated with large-vessel occlusion with and without intravenous infusion of tirofiban
Highly trabeculated structure of the human endocardium underlies asymmetrical response to low-energy monophasic shocks
Novel low-energy defibrillation therapies are thought to be driven by virtual-electrodes (VEs), due to the interaction of applied monophasic electric shocks with fine-scale anatomical structures within the heart. Significant inter-species differences in the cardiac (micro)-anatomy exist, however, particularly with respect to the degree of endocardial trabeculations, which may underlie important differences in response to low-energy defibrillation protocols. Understanding the interaction of monophasic electric fields with the specific human micro-anatomy is therefore imperative in facilitating the translation and optimisation of these promising experimental therapies to the clinic. In this study, we sought to investigate how electric fields from implanted devices interact with the highly trabeculated human endocardial surface to better understand shock success in order to help optimise future clinical protocols. A bi-ventricular human computational model was constructed from high resolution (350âÎŒm) ex-vivo MR data, including anatomically accurate endocardial structures. Monophasic shocks were applied between a basal right ventricular catheter and an exterior ground. Shocks of varying strengths were applied with both anodal [positive right ventricle (RV) electrode] and cathodal (negative RV electrode) polarities at different states of tissue refractoriness and during induced arrhythmias. Anodal shocks induced isolated positive VEs at the distal side of âdetachedâ trabeculations, which rapidly spread into hyperpolarised tissue on the surrounding endocardial surfaces following the shock. Anodal shocks thus depolarised more tissue 10âms after the shock than cathodal shocks where the propagation of activation from VEs induced on the proximal side of âdetachedâ trabeculations was prevented due to refractory endocardium. Anodal shocks increased arrhythmia complexity more than cathodal shocks during failed anti-arrhythmia shocks. In conclusion, multiple detached trabeculations in the human ventricle interact with anodal stimuli to induce multiple secondary sources from VEs, facilitating more rapid shock-induced ventricular excitation compared to cathodal shocks. Such a mechanism may help explain inter-species differences in response to shocks and help to develop novel defibrillation strategies
Facile microwave synthesis of uniform magnetic nanoparticles with minimal sample processing
We present a simple and rapid method for the synthesis of small magnetic nanoparticles (diameters in the order of 5â20 nm) and narrow size distributions (CV's of 20â40%). The magnetite nanoparticles were synthesized in green solvents within minutes and the saturation magnetization of the particles was tunable by changes in the reaction conditions. We show that this particle synthesis method requires minimal processing steps and we present the successful coating of the particles with reactive bisphosphonates after synthesis without washing or centrifugation. We found minimal batch-to-batch variability and show the scalability of the particle synthesis method. We present a full characterization of the particle properties and believe that this synthesis method holds great promise for facile and rapid generation of magnetic nanoparticles with defined surface coatings for magnetic targeting application
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