Waiting time distributions of the volatility in the Italian MIB30 index: Clustering or Poisson functions?

We investigate the time behaviour of the Italian MIB30 stock index collected every minute during two months in the period from May 17, 2006, up to July 24, 2006. We find short-range correlations in the price returns and, on the contrary, a long persistent time lag and slow decay in the autocorrelation functions of volatility. Besides, we find that the probability density functions (PDFs) of returns show fat tails, which are well fit by the log-normal model of Castaing [B. Castaing, Y. Gagne, E.J. Hopfinger, Physica D 46 (1990) 177], and a convergence toward a normal distribution for large time scales; we also find that the PDFs of volatility, for short time horizons, fit better with a log-normal distribution than with a Gaussian. Most of these features characterize the indexes and stocks of the largest American, European and Asian markets.We also investigate the distribution of stochastic separation between isolated strong events in the volatility signal. This is interesting because this gives us a deeper understanding about the price formation process. By using a test for the occurrence of local Poisson hypothesis, we show that the process we examined strongly departs from a Poisson statistics, the origin of this failure stemming from the presence of temporal clustering and of a certain amount of memory.     

Manganese dioxide oxidation of 3,4,4a,5-tetrahydro[1,2,4]triazino[6,1-c][1,4]benzoxazines

Since we developed [1] a synthetic entry to 3,4,4a,5-tetrahydro[1,2,4]triazino[6,1-c][1,4]benzoxazines 1 , we decided to explore the chemistry of this novel ring system. Its behaviour towards manganese dioxide is here described.     

Assessment of Growth Factors,Cytokines, and Cellular Markers in Saliva of Patients with Trigeminal Neuralgia

We proposed to perform a comparative analysis of growth factors, cytokines, and chemokine receptors on the salivary cells in the saliva obtained from trigeminal neuralgia (TN) and normal subjects. Saliva was collected from TN and healthy subjects. Salivary cells were isolated by centrifugation. The expression of the cell surface marker was analyzed by flow cytometry. A cytometric bead array was done to measure the levels of cytokines and growth factors on the flow cytometer. Saliva from TN subjects showed lower growth factor levels of Angiopoietin-2, bFGF, HGF, SCF, TGF-α, and VEGF and higher cytokine levels of IL-1β, TNF-α, CCL2, IL-17A, IL-6, and CXCL8, as well as higher expression levels of chemokine receptors CCR1 (CD191), CR3 (CD11b), CCR2 (CD192), CXCR5 (CD185), and CCR5 (CD196) in the cells from TN saliva. A certain set of cytokines and growth factors in the saliva, as well as chemokine receptors on salivary cells, could be a useful tool in the diagnostics and prognostics of trigeminal neuralgia. Trigeminal neuralgia is one of the significant pathological conditions in the class of chronic diseases around the world. Many targeted approaches are being tried by various research groups to utilize the information of the inflammatory microenvironment to resolve the pathology of chronic TN.     

Isolation and epimerization kinetics of the first diastereoisomer of an inherently chiral uranyl-salophen complex

The first diastereoisomeric mixture of an inherently chiral uranyl-salophen complex was prepared using (S)-naproxen as a chiral derivatizing agent. Slow crystallization from diisopropyl ether-chloroform afforded one pure diastereoisomer in 45% yield. Kinetic studies allowed the determination of the epimerization rate. [reaction--see text]     

Photophysical and electrochemical properties of chlorophyll a-cyclodextrins complexes

In this work, we have studied the interactions between two different cyclodextrins (CDs) and chlorophyll a (Chl a) in the presence of electrolyte by means of absorption, fluorescence spectroscopy, circular dichroism and cyclic voltammetry. The results obtained indicate that the presence of both CDs gives rise to an increase of Chl a solubility in water. In particular, heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin (TRIMEB) favours the dissolution of Chl a monomer in aqueous solution, whereas the presence of hydroxypropyl-beta-cyclodextrin (beta-HP-CD) promotes the pigment aggregation.     

Towards targeted MRI: new MRI contrast agents for sialic acid detection

The detection of sialic acid in living systems is of importance for the diagnosis of several types of malignancy. We have designed and synthesized two new lanthanide ion ligands (L1 and L2) that are capable of molecular recognition of sialic acid residues. The basic structure of these ligands consists of a DTPA-bisamide (DTPA, diethylenetriamine pentaacetic acid) whose amide moieties each bear both a boronic function for interaction with the diol groups in the side chain of sialic acid, and a functional group that is positively charged at physiologic pH values and is designed to interact with the carboxylate anion of sialic acid. The relaxometric properties of the Gd3+ complexes of these two ligands were evaluated. The relaxivity of the GdL1 complex has a significant second-sphere contribution at pH values above the pKa of its phenylboronic acid moiety. The interaction of the Gd3+ complexes of L1 and L2 with each of several saccharides was investigated by means of a competitive fluorescent assay. The results show that both complexes recognize sialic acid with good selectivity in the presence of other sugars. The adduct formed by GdL2 with sialic acid has the higher conditional formation constant (50.43+/-4.61 M(-1) at pH 7.4). The ability of such complexes to recognize sialic acid was confirmed by the results of a study on the interaction of corresponding radiolabeled complexes (153SmL1 and 153SmL2) with C6 glioma rat cells. 153SmL2 in particular is retained on the cell surface in significant amounts.     

Electrochemistry and electrochemiluminescence of [Ru(II)-tris(bathophenanthroline-disulfonate)]4- in aprotic conditions and aqueous buffers

In this work, the electrochemical and ECL properties of tris[1,10-phenanthrolinediyl-4,7-di(benzenesulfonate)]Ru(II) ([Ru(BPS)3]4-) have been addressed in both strictly aprotic conditions and aqueous buffers. A combined theoretical and experimental approach is presented to focus thermodynamics and kinetic effects of electro-generated species possessing highly negative charge. The complex, prepared as the sodium salt by using a newly developed procedure, was subsequently converted to the tetrabutylammonium salt by ion exchange, thus making it soluble in organic media and allowing, for the first time, its thorough electrochemical investigation in ultra-dry aprotic media. The electrochemically induced luminescence (ECL) of Na 4[Ru(BPS)3] in phosphate buffer, using the co-reactant method (tripropylamine), was investigated as a function of the electrode material and halide addition, and ECL intensities six times higher than that of [Ru(bpy)3]2+ were found. In addition, the ECL behavior of this promising dye for biomolecule recognition was investigated in aprotic media and, for the first time, the direct radical anion-radical cation annihilation ECL was obtained.     

Spatially resolved multidimensional cross-correlation relaxometry

Novel protocols are presented for acquiring one- and two-dimensional relaxation time spectra from selected subvolumes of a macroscopically heterogeneous sample. Although the protocols are generally applicable, special emphasis is given to their implementation on low-cost, low-field bench-top relaxometers lacking pulse shaping or pulsed gradient facilities.     

Multisliced ultrafast 2D relaxometry

By associating each slice in a spatially homogeneous sample with a different inversion-recovery delay time, multislice methods are used to reduce the acquisition times of 2D inversion-recovery T₁-T₂ relaxation spectra to just a few minutes. The increased speed comes at the expense of reduced signal/noise and this is reflected most noticeably in shifts in the component longitudinal relaxation times. Nevertheless, the major features of the 2D relaxation spectra are reproduced.     

Occurrence of aflatoxin M1 in milk samples from Italy analysed by online-SPE UHPLC-MS/MS

The occurrence of aflatoxin M1 in 69 milk samples collected in a south region of Italy in 2016 was evaluated. The samples were analysed using an automated method based on online SPE coupled with UHPLC tandem mass spectrometry. After a salt induced liquid–liquid extraction with acetonitrile to remove protein from milk, the extract was diluted with water and analysed using an automated online SPE MS/MS method. Among the analysed samples no one had AFM1 higher than the legally allowable limits whereas 71.4% of the other analysed samples were above the LOD of the method. The highest contamination level of AFM1 was found in pasteurised milk (44.39 ng kg^?1). The results show the worrying and widespread of AFM1 contamination, highlighting the necessity of monitoring studies in order to evaluate the reduction of the maximum legal limit.