Extension of plurisubharmonic currents

Let A be a closed subset of an open subset of ⁿ and T be a negative current on \ A of bidimension (p,p). Assume that T is psh and A is complete pluripolar such that the Hausdorff measure , then T extends to a negative psh current on . We also show that if T is psh or if dd ^cT extends to a current with locally finite mass on , then the trivial extension of T by zero across A exists in both cases: A is the zero set of a k–convex function with kp–1 or . Our basic tool is the following theorem [El3]: Let A be a closed complete pluripolar subset of an open subset of ⁿ and T be a positive current of bidimension (p,p) on \ A. Suppose that and exist (resp. exists and dd ^cT 0 on \ A), then there exists a positive (resp. closed positive) current S supported in A such that . Furthermore, we give a generalization of some theorems done by Siu and Ben Messaoud-El Mir and Alessandrini-Bassanelli without requiring anything from dT.     

Hydride Generation/Condensation System With an Inductively Coupled Argon Plasma Polychromator for Simultaneous Determination of Arsenic,Antimony, Selenium,Lead, Mercury and Tin in Honey

Abstract

An efficient method for the determination of nanogram levels of heavy metals in honey is described. Honey samples obtained in the field from farms located along the coast of the province of Cap-Bon (North Tunisia) were analysed by hydride generation with an inductively coupled argon plasma polychromator after a previous treatment in a microwave acid bomb.

An apparatus for the generation of volatile hydrides, interfaced with an inductively coupled argon plasma polychromator for simultaneous determination of As, Pb, Sb, Hg and Sn, is used. The optimum conditions for generating and determining the compounds and the effect of different parameters are discussed. The parameters investigated include: the chemical nature, form and concentration of the reductant, acid concentration of the sample and the carrier gas flow rate. Detection limits range 0.05 ng/ml for Hg to 1.1 ng/ml for Sb and precision values at 10 ng/ml are less than 6% of the relative standard deviation. Analytical protocols concerning analytical stages are exposed and discussed.     

Synthesis and characterization of new heptacyclic helicenes

New helically chiral substituted heptacyclic systems have been prepared from a simple phenanthrene building block in good yields and purity, via a four-step sequence involving palladium-catalysed Heck coupling and oxidative photocyclization. X-ray crystal structure analysis indicated that the conformation resembled that of the unsubstituted heptahelicene. The optical properties of these heptacyclic helicenes were investigated and show interesting behaviour.     

Synthesis and characterization of a new hexacyclic helicene

A new helically chiral hexacyclic system, bearing an acetoxymethyl group, was prepared from a simple naphthalene building block in good yield and purity, via a four-step sequence involving palladium-catalysed Heck couplings and oxidative photocyclizations. Suitable crystals of the latter indicate that its conformation closely resembles that of unsubstituted [6]helicene, whose idealized symmetry is C₂. The optical properties of the hexacyclic helicene were investigated and show interesting behaviour.     

Untargeted Phytochemical Profile,Antioxidant Capacity and Enzyme Inhibitory Activity of Cultivated and Wild Lupin Seeds from Tunisia

Lupin seeds can represent a valuable source of phenolics and other antioxidant compounds. In this work, a comprehensive analysis of the phytochemical profile was performed on seeds from three Lupinus species, including one cultivar (Lupinus albus) and two wild accessions (Lupinus cossentinii and Lupinus luteus), collected from the northern region of Tunisia. Untargeted metabolomic profiling allowed to identify 249 compounds, with a great abundance of phenolics and alkaloids. In this regard, the species L. cossentinii showed the highest phenolic content, being 6.54 mg/g DW, followed by L. luteus (1.60 mg/g DW) and L. albus (1.14 mg/g DW). The in vitro antioxidant capacity measured by the ABTS assay on seed extracts ranged from 4.67 to 17.58 mg trolox equivalents (TE)/g, recording the highest values for L. albus and the lowest for L. luteus. The DPPH radical scavenging activity ranged from 0.39 to 3.50 mg TE/g. FRAP values varied between 4.11 and 5.75 mg TE/g. CUPRAC values for lupin seeds ranged from 7.20 to 8.95 mg TE/g, recording the highest for L. cossentinii. The results of phosphomolybdenum assay and metal chelation showed similarity between the three species of Lupinus. The acetylcholinesterase (AChE) inhibition activity was detected in each methanolic extract analyzed with similar results. Regarding the butyrylcholinesterase (BChE) enzyme, it was weakly inhibited by the Lupinus extracts; in particular, the highest activity values were recorded for L. albus (1.74 mg GALAE/g). Overall, our results showed that L. cossentinii was the most abundant source of polyphenols, consisting mainly in tyrosol equivalents (5.82 mg/g DW). Finally, significant correlations were outlined between the phenolic compounds and the in vitro biological activity measured, particularly when considering flavones, phenolic acids and lower-molecular-weight phenolics.     

Efficient synthesis of new imidazo[1,2-b][1,2]benzothiazine 4,4-dioxide derivatives via lateral lithiation of N-mesitylenesulfonyl hydantoins

N-Mesitylenesulfonyl hydantoins, readily available from commercial α-amino acids, undergo lateral lithiation with an excess of lithium diisopropylamide and tetramethylethylenediamine in the presence of trimethylsilyl chloride to provide new imidazo[1,2-b][1,2]benzothiazin-2-one 4,4-dioxide derivatives in yields ranging from 44-65%.     

Temporal and spatial assessment of normal cerebrospinal fluid dynamics with MR imaging

The purpose of this study was to measure normal cerebrospinal fluid (CSF) pulsations within the intracranial and upper cervical subarachnoid spaces and the ventricular system. Phase contrast cine MR sequences were performed in sagittal and axial planes on 13 volunteers with flow encoding in the craniocaudal direction. CSF pulsations displayed considerable variations in healthy subjects, depending both on measurements localization and subjects, with CSF peak velocities ranging from 0 to 7 cm/s. In the subarachnoid spaces, the highest velocities occurred in the anterior location and increased from the cerebellar pontine angle cisterns towards the lower cervical spaces. In the ventricular system, the highest velocities occurred through the aqueduct of Sylvius. CSF flow within the third ventricle seemed to reflect a circular motion. There was a caudal net CSF flow in the aqueduct whereas in the upper cervical spaces net CSF flow was caudal anteriorly and cranial laterally. Velocity profiles of CSF pulsations demonstrated arterial morphology. After the R wave, caudal systolic motion was first observed in the posterior subarachnoid spaces, soon after in the anterior subarachnoid spaces and later in the ventricular system. Considering the morphology of CSF pathways, three successively initiated phenomena may explain the temporal course of CSF motion: the systolic expansion of the main arteries at the base of the brain, the systolic expansion of the cerebrospinal axis and, finally, the systolic expansion of the choroid plexuses.     

Task Specific Onium Salts and Ionic Liquids as Soluble Supports in <Emphasis Type="Italic">Grieco</Emphasis>’s Multicomponent Synthesis of Tetrahydroquinolines

Summary. In this work was presented an application of the use of task specific onium salts (TSOSs) as soluble supports in Grieco’s multicomponent synthesis of tetrahydroquinolines. These soluble supports are of wide applicability and combine advantages of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products were cleaved from the supports and obtained in pure form and good yields.