119 research outputs found
A geometric approach to time evolution operators of Lie quantum systems
Lie systems in Quantum Mechanics are studied from a geometric point of view.
In particular, we develop methods to obtain time evolution operators of
time-dependent Schrodinger equations of Lie type and we show how these methods
explain certain ad hoc methods used in previous papers in order to obtain exact
solutions. Finally, several instances of time-dependent quadratic Hamiltonian
are solved.Comment: Accepted for publication in the International Journal of Theoretical
Physic
Isolation of pregnancy-associated glycoproteins (PAG) from water buffalo (Bubalus bubalis) placenta by use of Vicia villosa bound agarose affinity chromatography
The present study describes the isolation and characterisation of new PAG molecules extracted from mid- and late-pregnancy placentas in the water buffalo (Bubalis bubalis). After extraction, acid and ammonium sulphate precipitation and DEAE chromatography water buffalo PAG (wbPAG) were enriched by Vicia villosa agarose (VVA) affininity chromatography. As determined by Western blotting with anti-PAG-sera, apparent molecular masses of immunoreactive bands from VVA peaks ranged from 59.5 to 75.8 kDa and from 57.8 to 80.9 kDa in the mid- and late- pregnancy placenta respectively. Aminoterminal microsequencing of proteins allowed the identification of three distinct wbPAG sequences wich have ben deposed in the SwissProt database: RGSXLTIHPLRNIRDFFYUG (Acc. n. P85048), RGSXLTILPLRNIID (P85049) and RGSXLTHLPLRNI (P85050). Their comparison to those previously identified revealed that two of them were new since they have not been described yet. Our results confirm the suitability of VVA chromatography in enrichment of multiple PAG molecules expressed in buffalo placenta. Productions of specific antisera can be very useful in immonoistochemical and immunocyitochemical studies of PAG expression in fetomaternal interfaces. Purified native PAG are also required for development on specific immoassays (RIA/ELISA) currently used for pregnancy diagnosis and physiological investigation in farm animal
A New Polymeric Minimally Invasive Glaucoma Implant
Glaucoma drainage devices are implanted in the eye to treat glaucoma, a disease that can cause vision loss and blindness. These devices are designed to reduce intraocular pressure (IOP), a major risk factor for the progression of glaucoma, by providing an alternative outflow path for the fluid produced by the eye, the aqueous humor. Here, a novel polymeric minimally invasive glaucoma implant designed to enhance aqueous humor outflow is demonstrated. The implant is made of a unique, potentially biodegradable thermoplastic material, polycarbonate bisamide (PC-BA), and produced through replica molding using hot embossing and femtosecond laser-machined glass molds. Post-mortem experiments demonstrate successful device implantation into a rabbit's eye, with the implant remaining securely in place. Although the mass loss and changes in molecular weight observed in the in vitro degradation experiments are not significant within the tested times and degradation conditions, the PC-BA is a slow-degradation polymer that may take a few years to fully degrade. Thus, the implant will also slowly degrade and be absorbed by the body over time, leaving behind a natural outflow pathway. This potentially biodegradable glaucoma implant may represent a promising new approach for restoring outflow in a more natural way.</p
Supercoherent States, Super K\"ahler Geometry and Geometric Quantization
Generalized coherent states provide a means of connecting square integrable
representations of a semi-simple Lie group with the symplectic geometry of some
of its homogeneous spaces. In the first part of the present work this point of
view is extended to the supersymmetric context, through the study of the
OSp(2/2) coherent states. These are explicitly constructed starting from the
known abstract typical and atypical representations of osp(2/2). Their
underlying geometries turn out to be those of supersymplectic OSp(2/2)
homogeneous spaces. Moment maps identifying the latter with coadjoint orbits of
OSp(2/2) are exhibited via Berezin's symbols. When considered within
Rothstein's general paradigm, these results lead to a natural general
definition of a super K\"ahler supermanifold, the supergeometry of which is
determined in terms of the usual geometry of holomorphic Hermitian vector
bundles over K\"ahler manifolds. In particular, the supergeometry of the above
orbits is interpreted in terms of the geometry of Einstein-Hermitian vector
bundles. In the second part, an extension of the full geometric quantization
procedure is applied to the same coadjoint orbits. Thanks to the super K\"ahler
character of the latter, this procedure leads to explicit super unitary
irreducible representations of OSp(2/2) in super Hilbert spaces of
superholomorphic sections of prequantum bundles of the Kostant type. This work
lays the foundations of a program aimed at classifying Lie supergroups'
coadjoint orbits and their associated irreducible representations, ultimately
leading to harmonic superanalysis. For this purpose a set of consistent
conventions is exhibited.Comment: 53 pages, AMS-LaTeX (or LaTeX+AMSfonts
Variations in plasma matrix metalloproteinases and placental pregnancy - associated glycoproteins during gestation in rabbits
[EN] Adaptation to pregnancy involves major maternal anatomical, physiological and metabolic modifications to support the mother's metabolic needs and those of the growing foetus. Invasion of embryonic territories and implantation in humans and other mammals is the result of an active biochemical process. The invasive faculty of cytotrophoblastic cells depends on their capacity to secrete proteolytic enzymes such as matrix metalloproteinases (MMPs). Many studies have addressed the variations in MMPs in placental tissues, but few have reported on their measurements in plasma. Furthermore, the Pregnancy-Associated Glycoproteins (PAGs), which are synthesized in the syncytiotrophoblast and used as early markers of pregnancy in domestic and wild animals, have not yet been studied in rabbits. In this study, we attempt to purify PAGs from rabbit placenta using a previously described methodology and to measure their concentrations as well as those of MMP-2 and MMP-9 in the plasma throughout pregnancy. In the course of the work, we noted certain modifications of the biochemical parameters in plasma during gestation, essentially in glycemia and lipemia. We detected proteins immunologically-related to PAGs in placental extracts between D14 to D21. Until now, it has been impossible to develop a homologous RIA in order to measure PAGs in rabbit plasma, as the recovery of PAGs during the purification procedure was very low and PAGs were undetectable in rabbit plasma using heterologous RIAs. Finally, we demonstrated a rise in MMP-2 and -9 at the middle and the end of the gestation. However, the small variations presented by these matrix metalloproteinases preclude the use of plasma levels of these enzymes as early markers of pregnancy progress in the rabbit.Financial support for this study was obtained from DRS and INSERM (accord INSERM-DRS) and the authors wish to thank Mary Osbone-Pellegrin for editing the manuscript.Othmani-Mecif, K.; Benazzoug, Y.; Jacob, M.; Beckers, J. (2006). Variations in plasma matrix metalloproteinases and placental pregnancy - associated glycoproteins during gestation in rabbits. World Rabbit Science. 14(1). doi:10.4995/wrs.2006.542SWORD14
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