3,674 research outputs found
Acylsulfonamide safety-catch linker : promise and limitations for solid-phase oligosaccharide synthesis
Safety-catch linkers are useful for solid-phase oligosaccharide synthesis as they are orthogonal to many common protective groups. A new acylsulfonamide safety-catch linker was designed, synthesized and employed during glycosylations using an automated carbohydrate synthesizer. The analysis of the cleavage products revealed shortcomings for oligosaccharide synthesis
GePEToS : A Geant4 Monte Carlo simulation package for Positron Emission Tomography
GePEToS is a simulation framework developed over the last few years for
assessing the instrumental performance of future PET scanners. It is based on
Geant4, written in Object-Oriented C++ and runs on Linux platforms. The
validity of GePEToS has been tested on the well-known Siemens ECAT EXACT HR+
camera. The results of two application examples are presented : the design
optimization of a liquid Xe micro-PET camera dedicated to small animal imaging
as well as the evaluation of the effect of a strong axial magnetic field on the
image resolution of a Concorde P4 micro-PET camera.Comment: 5 pages, 12 figures, submitted to IEEE Transactions on Nuclear
Scienc
Glycosylation efficiencies on different solid supports using a hydrogenolysis-labile linker
Optical microsphere resonators: optimal coupling to high-Q whispering gallery modes
A general model is presented for coupling of high- whispering-gallery
modes in optical microsphere resonators with coupler devices possessing
discrete and continuous spectrum of propagating modes. By contrast to
conventional high-Q optical cavities, in microspheres independence of high
intrinsic quality-factor and controllable parameters of coupling via evanescent
field offer variety of regimes earlier available in RF devices. The theory is
applied to the earlier-reported data on different types of couplers to
microsphere resonators and complemented by experimental demonstration of
enhanced coupling efficiency (about 80%) and variable loading regimes with
Q>10^8 fused silica microspheres.Comment: 14 pages, 4 figure
Experimental study of a liquid Xenon PET prototype module
A detector using liquid Xenon in the scintillation mode is studied for
Positron Emission Tomography (PET). The specific design aims at taking full
advantage of the liquid Xenon properties. It does feature a promising
insensitive to any parallax effect. This work reports on the performances of
the first LXe prototype module, equipped with a position sensitive PMT
operating in the VUV range (178 nm).Comment: Proc. of the 7th International Workshops on Radiation Imaging
Detectors (IWORID-7), Grenoble, France 4-7 July 200
Mode structure and ray dynamics of a parabolic dome microcavity
We consider the wave and ray dynamics of the electromagnetic field in a
parabolic dome microcavity. The structure of the fundamental s-wave involves a
main lobe in which the electromagnetic field is confined around the focal point
in an effective volume of the order of a cubic wavelength, while the modes with
finite angular momentum have a structure that avoids the focal area and have
correspondingly larger effective volume. The ray dynamics indicates that the
fundamental s-wave is robust with respect to small geometrical deformations of
the cavity, while the higher order modes are associated with ray chaos and
short-lived. We discuss the incidence of these results on the modification of
the spontaneous emission dynamics of an emitter placed in such a parabolic dome
microcavity.Comment: 50 pages, 17 figure
A liquid Xenon Positron Emission Tomograph for small animal imaging : first experimental results of a prototype cell
A detector using liquid Xenon (LXe) in the scintillation mode is studied for
Positron Emission Tomography (PET) of small animals. Its specific design aims
at taking full advantage of the Liquid Xenon scintillation properties. This
paper reports on energy, time and spatial resolution capabilities of the first
LXe prototype module equipped with a Position Sensitive Photo- Multiplier tube
(PSPMT) operating in the VUV range (178 nm) and at 165 K. The experimental
results show that such a LXe PET configuration might be a promising solution
insensitive to any parallax effect.Comment: 34 pages, 18 pages, to appear in NIM
Ca-NIR: a ratiometric near-infrared calcium probe based on a dihydroxanthene-hemicyanine fluorophore.
Fluorescent calcium probes are essential tools for studying the fluctuation of calcium ions in cells. Herein, we developed Ca-NIR, the first ratiometric calcium probe emitting in the near infrared region. This probe arose from the fusion of a BAPTA chelator and a dihydroxanthene-hemicyanine fluorophore. It is efficiently excited with common 630-640 nm lasers and displays two distinct emission bands depending on the calcium concentration (Kd = ∼8 μM). The physicochemical and spectroscopic properties of Ca-NIR allowed for ratiometric imaging of calcium distribution in live cells.journal article2017 Jun 01imported"Supporting information" disponible sur le site de l'éditeu
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