Search results for "square"
showing 10 items of 1317 documents
Science based calibration for the extraction of 'analyte-specific' HPLC-DAD chromatograms in environmental analysis
2010
Multivariate science based calibration (SBC) has been applied to the resolution of overlapped peaks in liquid chromatography with diode array detection (LC-DAD). Complex river water samples spiked with 11 pharmaceutical substances resulted in poorly resolved chromatograms containing additional peaks from interfering matrix compounds and a change in the background absorbance due to the mobile phase gradient. Applying the present multivariate approach it was possible to resolve all 11 analytes from overlapping peaks, obtaining linear calibration lines (R2 > 0.96). Recovery percentages on spiked samples ranged between 74.6 and 113.5%, which are quite satisfactory taking into account the low co…
Multivariate optimization approach for chiral resolution of drugs using human serum albumin in affinity electrokinetic chromatography-partial filling…
2005
The enantiomeric resolution of chiral compounds using HSA by means of affinity EKC (AEKC)-partial filling technique is the result of a delicate balance between different experimental variables such as protein concentration, running pH (background electrophoretic buffer, protein and compound solutions) and protein solution plug length. In this paper multivariate optimization approaches for chiral separation of four basic drugs (alprenolol, oxprenolol, promethazine and propranolol) using HSA as chiral selector in AEKC-partial filling technique are studied. The experimental conditions to achieve maximum resolution are optimized using the Box-Behnken experimental design. Partial least squares a…
Determination of biochemical parameters in human serum by near-infrared spectroscopy
2014
NIR offers multiple advantages for serum analysis, permitting a fast and direct determination of several parameters simultaneously, with low sample handling and without the need for reagents during the measurement step. The aim of this paper was to provide an evaluation of this technique in a real world scale, for the simultaneous determination of several parameters and based on a considerable number of samples. Direct near infrared (NIR) absorbance measurements were used to determine the concentration of clinical parameters in human serum that are required in routine biochemical tests. Total protein, albumin, total cholesterol, high-density lipoprotein (HDL cholesterol), low-density lipopr…
A circular mesh scheme for the non-orthogonal finite difference time domain method
2002
Beam forming networks (BFN) are an important component of a complex satellite antenna system because they are used to provide accurate amplitude and phase excitation to the elements of the feed network. The need for handling high power and the need for a high degree of integrability, often leads one to choose square coaxial metal lines for constructing BFNs. BFNs usually require variable power dividers such as the rat-race (or ring) couplers with constant or variable divider ratios in order to deliver a prescribed amount of power to a certain element of an antenna array to steer the beam in a desired direction. However, modeling of such circular structures in square coaxial form is not an e…
Dinuclear and tetranuclear complexes of copper coordinated by an anthracene-based new μ-bis(tridentate) ligand: Synthesis, structure, spectroscopy an…
2016
Abstract Copper(II) complexes of an anthracene-based new μ-bis(tridentate) ligand, N,N′-bis[anthracene-2-ylmethyl]-N,N′-bis[carboxymethyl]-1,3-diaminopropan-2-ol (H3acdp) with mixed donating groups, have been studied in solid state as well as in solution. The reaction of stoichiometric amounts of CuSO4·5H2O and the ligand H3acdp in the presence of NaOH at ambient temperature in methanol-dichloromethane, afforded a new dinuclear copper complex, [Cu2(acdp)(MeO)(MeOH)2] (1). On the other hand, the reaction of stoichiometric amounts of Cu(OAc)2·H2O and the ligand H3acdp in the presence of NaOH at ambient temperature in methanol-dichloromethane yielded, a novel tetranuclear copper complex, [Cu4(…
Thermodynamic and fluorescence emission studies on chemosensors containing anthracene fluorophores. Crystal structure of {[CuL1Cl]Cl}2·2H2O [L1 = N-(…
1999
The co-ordination capabilities toward hydrogen ions, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+ of the novel receptor 2,6,9,13-tetraaza[14](9,10)anthracenophane (L) and of its open-chain counterpart N-(3-aminopropyl)-N′-3-(anthracen-9-ylmethyl)aminopropylethane-1,2-diamine (L1) is described. Stepwise protonation constants of the cyclic receptor (L) are lower than those of the open-chain receptor (L1) . Quenching effects of the fluorescence emission occur upon first and second deprotonation of L and upon second deprotonation of L1. Stability constants of the Co2+, Ni2+, Cu2+, Zn2+ and Cd2+ complexes follow the Irving–Williams trend and are intermediate between those of triethylenetetraamine with termin…
Adherence to antithrombotic therapy guidelines improves mortality among elderly patients with atrial fibrillation: insights from the REPOSI study
2016
Background: Atrial fibrillation (AF) is associated with a substantial risk of thromboembolism and mortality, significantly reduced by oral anticoagulation. Adherence to guidelines may lower the risks for both all cause and cardiovascular (CV) deaths. Methods: Our objective was to evaluate if antithrombotic prophylaxis according to the 2012 European Society of Cardiology (ESC) guidelines is associated to a lower rate of adverse outcomes. Data were obtained from REPOSI; a prospective observational study enrolling inpatients aged ≥65 years. Patients enrolled in 2012 and 2014 discharged with an AF diagnosis were analysed. Results: Among 2535 patients, 558 (22.0 %) were discharged with a diagnos…
Gender-related effect of clinical and genetic variables on the cognitive impairment in multiple sclerosis
2004
BACKGROUND: Cognitive impairment may occur at any time during the course of multiple sclerosis (MS), and it is often a major cause of disability in patients with the disease. The APOE-epsilon4 allele is the major known genetic risk factor for late onset familial and sporadic Alzheimer's Disease (AD), and it seems to be implicated in cognitive decline in normal elderly persons. OBJECTIVE: To investigate the clinical and genetic variables that can be associated with the cognitive decline in patients with MS. METHODS: Five-hundred and three patients with clinically definite MS underwent a battery of neuropsychological tests and, according to the number of failed tests, were divided into cognit…
An APOE haplotype associated with decreased ε4 expression increases the risk of late onset Alzheimer's disease.
2011
This paper addresses a tenet of the literature on APOE, i.e., the relationship between the effects of the e4, one of the established genetic risk factor for Alzheimer's disease (AD), and its expression levels as determined by APOE promoter polymorphisms. Five polymorphisms (-491 rs449647, -427 rs769446, -219 rs405509, and e rs429358-rs7412) were studied in 1308 AD patients and 1082 control individuals from the Central-Northern Italy. Major findings of the present study are the following: 1) the variants -219T and e4 increase the risk for late onset AD (LOAD) when they are both present in cis on the same chromosome (in phase); 2) the correlation between the haplotype (-219T/e4) and AD risk p…
No association between Glu298Asp endothelial nitric oxide synthase polymorphism and Italian sporadic Alzheimer's disease.
2003
A great amount of evidence suggests that neuroinflammation may be a major pathogenetic mechanism in the pathophysiology of sporadic Alzheimer's Disease (sAD). Recently, polymorphisms in the endothelial nitric oxide synthase (NOS3) gene have been associated to late onset Alzheimer's Disease in a British population. However, other groups failed to replicate this finding in Asiatic and Caucasian populations. We conducted a case-control study including a clinically well-defined group of 149 sAD patients and 149 age and sex matched controls to test the association between NOS3 Glu298Asp polymorphism and sAD in an ethnically homogenous Italian population. All subjects were genotyped at NOS3 and a…