A Variational Approach to the Macroscopic Electrodynamics of Anisotropic Hard Superconductors

We consider Bean’s critical state model for anisotropic superconductors. A variational problem solved by the quasi-static evolution of the internal magnetic field is obtained as the Γ-limit of functionals arising from Maxwell’s equations combined with a power law for the dissipation. Moreover, the quasi-static approximation of the internal electric field is recovered, using a first order necessary condition. If the sample is a long cylinder subjected to an axial uniform external field, the macroscopic electrodynamics is explicitly determined.     

Sesquiterpenoids of the Sponge Dysidea fragilis of the North-Brittany Sea

The title sponge is shown to contain eight new sesquiterpenoids for which a common, unusual biogenetic origin is postulated. The compounds are shown to be: (–)-(1R*,4R*)-3-(3′-furyl)methyl-2-p-menthen-7-yl acetate ((–)- 8b ); two diols separated as the monoacetates (–)-(1S*,4R*)-3-(3′-furyl)methyl-l-hydroxy-2-p-menthen-7-yl acetate ((–)- 13a ) and the (–)-(1R*,4R*)-epimer (–)- 13b , the two C(4)-epimeric 4-ethoxy-3-(1′(7′),2′-p-menthadien-3′-yl)methyl-2-buten-4-olides ((+)- 14a and (–)- 14b ), (–)-3-(3′-furyl)methyl-7-nor-2-p-menthen-l-one ((–)- 11 ), (–)-(3Z)-1-(3′-furyl)-4,8-dimethylnona-3, 7-dien-2-yl acetate ((–)- 17 ), and (+)-3-(5′,7′-seco-2′(10′)-pinen-7′-yl)methylfuran ((+)- 15 ).     

A new solution for an old problem: the regiochemical distribution of the acyl chains in galactolipids can be established by electrospray ionization tandem mass spectrometry

Electrospray ionization-quadrupole ion trap mass spectrometry (ESI-QITMS), either in positive- or in negative-ion mode, has been used to establish the chemical structures (chain length, degree of unsaturation, positional distribution) of the fatty acids attached to the primary (sn-1) and secondary (sn-2) hydroxyl groups of the glycerol moiety of natural monogalactosyl- (MGDG) and digalactosyldiacylglycerols (DGDG), isolated from the freshwater dinoflagellate Glenodinium sanguineum and from a marine diatom belonging to the genus Chaetoceros. Fragmentation by collision-induced dissociation of a single component in MGDG and DGDG mixtures, separated by high-performance liquid chromatography (HPLC) and detected on-line by tandem positive-ion ESI-MS, leads to a clear-cut determination of the positional distribution of the sn-glycerol-bound fatty acyl chains. Reversed-phase liquid chromatography allowed a partial resolution of the component mixture before ESI-MS/MS analysis. These results were validated by comparison with ESI-MS data obtained for the sn-2 lysoglyceroglycolipids synthesized via regiospecific enzymatic hydrolysis of the corresponding diacylglycerols by Rhizopus arrhizus lipase.     

Magnetic dipolar coupling and collective effects for binary information codification in cost-effective logic devices

Physical limitations foreshadow the eventual end to traditional Complementary Metal Oxide Semiconductor (CMOS) scaling. Therefore, interest has turned to various materials and technologies aimed to succeed to traditional CMOS. Magnetic Quantum dot Cellular Automata (MQCA) are one of these technologies. Working MQCA arrays require very complex techniques and an excellent control on the geometry of the nanomagnets and on the quality of the magnetic thin film, thus limiting the possibility for MQCA of representing a definite solution to cost-effective, high density and low power consumption device demand. Counter-intuitively, moving towards bigger sizes and lighter technologies it is still possible to develop multi-state logic devices, as we demonstrated, whose main advantage is cost-effectiveness. Applications may be seen in low cost logic devices where integration and computational power are not the main issue, eventually using flexible substrates and taking advantage of the intrinsic mechanical toughness of systems where long range interactions do not need wirings. We realized cobalt micrometric MQCA arrays by means of Electron Beam Lithography, exploiting cost-effective processes such as lift-off and RF sputtering that usually are avoided due to their low control on array geometry and film roughness. Information relative to the magnetic configuration of MQCA elements including their eventual magnetic interactions was obtained from Magnetic Force Microscope (MFM) images, enhanced by means of a numerical procedure and presented in differential maps. We report the existence of bi-stable magnetic patterns, as detected by MFM while sampling the z-component of magnetic induction field, arising from dipolar inter-element magnetostatic coupling, able to store and propagate binary information. This is achieved despite the array quality and element magnetic state, which are low and multi-domain, respectively. We discuss in detail shape, inter-element spacing and dot profile effects on the magnetic coupling. Numerical Finite Element Method (FEM) simulations show a possible microspin arrangement producing such magnetostatic coupling.     

Some estimates of the minimizing properties of web functions

We study a general class of functionals over and we approximate their infimum by means of the minimum in the space of web functions. We provide several tools for estimating this approximation and we study in detail some meaningful models. Received: 13 July 2000 / Accepted: 11 May 2001 / Published online: 19 October 2001     

Clinical evaluation of Moro (Citrus sinensis (L.) Osbeck) orange juice supplementation for the weight management

In the last years, several studies have recently evaluated the beneficial effects of red orange juice (Citrus sinensis (L.) Osbeck) and its active components in weight management and obesity. Moro orange is a cultivar of red orange, particularly rich in active compounds such as anthocyanins, hydroxycinnamic acids, flavone glycosides and ascorbic acid, which displays anti-obesity effects in in vitro and in vivo studies. In this clinical study, the effect of a Moro juice extract (Morosil^®, 400 mg/die) supplementation was evaluated in overweight healthy human volunteers for 12 weeks. Results showed that Moro juice extract intake was able to induce a significant reduction in body mass index (BMI) after 4 weeks of treatment (p < 0.05). Moreover, in subjects treated with Moro extract, body weight, BMI, waist and hip circumference were significantly different from the placebo group (p < 0.05). In conclusion, it could be suggested that the active compounds contained in Moro juice have a synergistic effect on fat accumulation in humans and Moro juice extract can be used in weight management and in the prevention of human obesity.     

Structure of Solutions of Multidimensional Conservation Laws with Discontinuous Flux and Applications to Uniqueness

We investigate the structure of solutions of conservation laws with discontinuous flux under quite general assumption on the flux. We show that any entropy solution admits traces on the discontinuity set of the coefficients and we use this to prove the validity of a generalized Kato inequality for any pair of solutions. Applications to uniqueness of solutions are then given.     

Rarisetenolide,Epoxyrarisetenolide, and Epirarisetenolide,New-Skeleton Sesquiterpene Lactones as Taxonomic Markers and Defensive Agents of the Marine Ciliated Morphospecies Euplotes rariseta

Rarisetenolide ( 3 ) and epoxyrarisetenolide ( 4 ), new-skeleton α,β-conjugated sesquiterpene lactones, were isolated from various strains of the unicellular ciliated protist Euplotes rariseta collected from marine coasts widely far apart from each other: northern and southern Australia, southern Brazil, and Canary Islands. A strain of E. rariseta from New Zealand gave epirarisetenolide ( 5 ) instead, revealing a subtle variability in secondary metabolism for this ciliated morphospecies. Nonetheless, these metabolites – which are the first non-aldehydic terpenoids so far isolated from ciliates – represent a unique whole that constitutes a reliable taxonomic tool at the morphospecies level. Epirarisetenolide ( 5 ) and rarisetenolide ( 3 ), in this order, showed higher toxicity towards nonproductive ciliates than the chemically more reactive natural epoxide 4 and the semisynthetic aldehyde/protected-aldehyde froms 8/7a/7b . This inverse trend of biological vs. chemical effectiveness suggests that these cytotoxic agents interact noncovalently with membrane receptors.     

PENTACOORDINATE SPIROCYCLIC DERIVATIVES OF THE 2H-1,2,3-DIAZAPHOSPHOLE SYSTEM

Abstract

Stable spirocyclic phosphoranes 2 have been prepared stereospecifically in high yields (90–95%) by reaction of o-azidophenol with cis and trans-diazaphosphole derivatives 1. Slow isomerization of pure diastereoisomer 2 was observed in acidic conditions.