Publications by authors named "Martin O"

Excitations of three-dimensional spin glasses are computed numerically. We find that one can flip a finite fraction of an LxLxL lattice with an O(1) energy cost, confirming the mean-field picture of a nontrivial spin overlap distribution P(q). These low energy excitations are not domain-wall-like, rather they are topologically nontrivial and they reach out to the boundaries of the lattice.

View Article and Find Full Text PDF

The efficient synthesis of the iminoalditols derivatives 1 and 2 (nojirimycin alpha-C-glycosides) has been achieved in 10 steps from commercially available 2,3;4,6-di-O-isopropylidene-alpha-L-sorbofuranose in an overall yield of 23-27%.

View Article and Find Full Text PDF

Autocrine expression of VEGF has been detected in endothelial cells under hypoxia or oxidative stress. However, the functional significance of this VEGF autocrine expression remains undefined. To analyze the role of autocrine VEGF in the endothelial response against injury, cultured bovine aorta endothelial cells (BAEC) were challenged with potentially cytotoxic substances with different chemical structure and pharmacologic properties, namely cytochalasin D (CyD), hydrogen peroxide (H2O2) and cyclosporine A (CsA).

View Article and Find Full Text PDF

Reticular dysgenesis is a rare inherited immunodeficiency characterized by the lack of blood monocytes and neutrophils and low lymphocyte counts, contrasting with normal red blood cell counts and normal or decreased platelet counts. Whether dendritic cells or macrophages, both of which derive primarily from blood monocytes, are affected in this condition remains unknown. We studied 7 patients with reticular dysgenesis.

View Article and Find Full Text PDF

Fabry disease is a lysosomal storage disorder caused by deficient lysosomal alpha-galactosidase A (alpha-Gal A) activity. Deficiency of the enzyme activity results in progressive deposition of neutral glycosphingolipids with terminal alpha-galactosyl residue in vascular endothelial cells. We recently proposed a chemical chaperone therapy for this disease by administration of 1-deoxygalactonojirimycin, a potent inhibitor of the enzyme, at subinhibitory intracellular concentrations [Fan, J.

View Article and Find Full Text PDF

The N-terminal region of parathyroid hormone (PTH) and PTH-related protein (PTHrP) interacts with a common PTH/PTHrP receptor in osteoblasts. These cells synthesize PTHrP, but its role in bone turnover is unclear. Intermittent treatment with N-terminal PTHrP or PTH stimulates bone growth in vivo, possibly by increasing local bone factors.

View Article and Find Full Text PDF

We study the plasmon resonances of 10 (nm)--100 (nm) two-dimensional metal particles with a non-regular shape. Movies illustrate the spectral response of such particles in the optical range. Contrary to particles with a simple shape (cylinder, ellipse) non-regular particles exhibit many distinct resonances over a large spectral range.

View Article and Find Full Text PDF

Human subjects performed, from a standing position, rapid hand pointings to visual targets located within or beyond the prehension space. To examine the interaction between posture and the goal-directed movement we introduced a visual double-step perturbation requiring a reprogramming of the hand movement. Trials directed towards the same spatial goal but differentiated only by the likeliness of a visual double-step were compared.

View Article and Find Full Text PDF

The structure of a homonojirimycin isomer isolated from Aglaonema treublii and originally proposed as alpha-3,4-di-epi-homonojirimycin was revised to alpha-4-epi-homonojirimycin 3 ("alpha-homoallonojirimycin") on the basis of NMR analysis and synthetic studies. Its activity as a glycosidase inhibitor is compared to that of other homonojirimycin isomers.

View Article and Find Full Text PDF

Currently, two different formulations of Ty21a live oral typhoid vaccine are commercialized. The enteric-coated capsule formulation was licensed based on results of three years of follow-up of a randomized, placebo-controlled, double-blind field trial in Area Occidente, Santiago, Chile, which demonstrated that three doses of this formulation, given on an every other day immunization schedule, conferred the best protection among several options evaluated. Subsequently, a liquid formulation (lyophilized vaccine organisms reconstituted with buffer and water into a vaccine cocktail) was commercialized after it was shown to provide superior protection than enteric-coated capsules over three years of follow-up in a randomized, placebo-controlled field trial in Area Sur Oriente and Area Norte, Santiago.

View Article and Find Full Text PDF

The performances of a deafferented patient and five control subjects have been studied during a self-driven passing task in which one hand has to grasp an object transported by the other hand and in a unimanual reach-to-grasp task. The kinematics of the reach and grasp components and the scaling of the grip aperture recorded for the self-driven passing task were very similar in controls and the deafferented subject (GL). In contrast, for the unimanual task when vision was absent, GL's coordination between reaching and grasping was delayed in space and time compared with the control subjects.

View Article and Find Full Text PDF

The capability of reprogramming movement responses following changes in the visual goal has been studied through the double-step paradigm. These studies have shown that: (a) continuous internal feedback-loops correct unconsciously the dynamic errors throughout the movement; (b) proprioceptive information and/or the efference copy have a privileged status among central processes, insuring on-line regulation of the initial motor commands; and (c) generation of the motor program starts after target presentation, and is continuously updated in the direction of the current internal representation of the target, at least until the onset of hand movement. This main corrective process of the initial program appears to be basically independent of visual reafference from the moving hand.

View Article and Find Full Text PDF

In the post-embryonic life, physiological angiogenesis is tightly controlled. Angiogenesis also occurs in pathological circumstances such as tumor vessel proliferation, retinal neovascularization and ischemia. The development of collateral circulation is not only not deleterious, but life saving.

View Article and Find Full Text PDF

We illustrate the propagation of light in a new type of coupling mask for lensless optical lithography. Our investigation shows how the different elements comprising such masks contribute to the definition of an optical path that allows the exposure of features in the 100-nm-size range in the photoresist.

View Article and Find Full Text PDF

Background And Study Aims: Endoscopic sphincterotomy is a widely used and safe procedure for the management of common bile duct stones, but little attention has been paid to the design of the sphincterotome and its influence upon risk of sphincterotomy. This study was undertaken to evaluate a sphincterotome, designed to incorporate known and original aspects which may contribute to safety.

Patients And Methods: 144 patients with bile duct stones were evaluated in an open prospective study of the use of the sphincterotome in performing endoscopic sphincterotomy.

View Article and Find Full Text PDF

In daily living, we continuously interact with our environment. This environment is rarely stable and living beings show remarkable adaptive capacities. When we reach for an object, it is necessary to localize the position of this object with respect to our own body before programming an adequate arm movement.

View Article and Find Full Text PDF

Previous studies indicate that gamma tubulin ring complex (gammaTuRC) can nucleate microtubule assembly and may be important in centrosome formation. gammaTuRC contains approximately eight subunits, which we refer to as Xenopus gamma ring proteins (Xgrips), in addition to gamma tubulin. We found that one gammaTuRC subunit, Xgrip109, is a highly conserved protein, with homologues present in yeast, rice, flies, zebrafish, mice, and humans.

View Article and Find Full Text PDF

The interactions of Bombyx mori nucleopolyhedrovirus (BmNPV) with Spodoptera frugiperda cells (Sf9) were investigated. S. frugiperda cells are usually considered nonpermissive for BmNPV.

View Article and Find Full Text PDF

The French psychologist Alfred Binet is at the origin of the development of the mental test intended for diagnosing the intellectual level of children. Initially conceived as clinical tests their importation to the United States during the 1910's has considerably altered their use, significance and interpretation. Turned into political tools by eugenicists and hereditarists and used in large-scale selection operations, the tests have changed the psychologists' conception of intelligence: initially conceived as multifacted and qualitative, intelligence had become a single quantifiable entity.

View Article and Find Full Text PDF

N-[5-(5, 7-dimethyl Bodipy)-1-pentanoyl]-D-erythro-sphingosylphosphorylcholine (C5-DMB-SM), a fluorescent analog of sphingomyelin, has been used in a study of the formation of very early endosomes in human skin fibroblasts. This lipid exhibits a shift in its fluorescence emission maximum from green (approximately 515 nm) to red (approximately 620 nm) wavelengths with increasing concentrations in membranes. When cells were incubated with 5 microM C5-DMB-SM at 4 degrees C and washed, only plasma membrane fluorescence (yellow-green) was observed.

View Article and Find Full Text PDF

beta-Homonojirimycin (2) was prepared by the highly stereoselective double reductive amination of a 2,6-heptodiulose derivative (6 or 13) using ammonium formate and NaBH(3)CN. The process was unsuccessful with primary amines. The synthesis of N-butyl-beta-homonojirimycin (19) was achieved by the N-butanoylation of a derivative of 2 followed by the reduction of the resulting tertiary amide.

View Article and Find Full Text PDF