Yb-Doped Silicate Glasses as Optical Sensor Materials for Cryogenic Thermometry.

Optical sensors constitute attractive alternatives to resistive probes for the sensing and monitoring of temperature (). In this work, we investigated, in the range from 2 to 300 K, the thermal behavior of Yb ion photoluminescence (PL) in glass hosts for cryogenic thermometry. To that end, two kinds of Yb-doped preforms, with aluminosilicate and aluminophosphosilicate core glasses, were made using the modified chemical vapor deposition (MCVD) technique.

Performance Study of a Zirconia-Doped Fiber for Distributed Temperature Sensing by OFDR at 800 °C.

Optical Frequency Domain Reflectometry (OFDR) is used to make temperature distributed sensing measurements along a fiber by exploiting Rayleigh backscattering. This technique presents high spatial and high temperature resolutions on temperature ranges of several hundred of degrees Celsius. With standard telecommunications fibers, measurement errors coming from the correlation between a high temperature Rayleigh trace and the one taken as a reference at room temperature could be present at extremely high temperatures.

Investigation of the Incorporation of Cerium Ions in MCVD-Silica Glass Preforms for Remote Optical Fiber Radiation Dosimetry.

The incorporation of Ce ions in silicate glasses is a crucial issue for luminescence-based sensing applications. In this article, we report on silica glass preforms doped with cerium ions fabricated by modified chemical vapor deposition (MCVD) under different atmospheres in order to favor the Ce oxidation state. Structural analysis and photophysical investigations are performed on the obtained glass rods.

Discovery of a Potent Dual Inhibitor of Acetylcholinesterase and Butyrylcholinesterase with Antioxidant Activity that Alleviates Alzheimer-like Pathology in Old APP/PS1 Mice.

The combination of the scaffolds of the cholinesterase inhibitor huprine Y and the antioxidant capsaicin results in compounds with nanomolar potencies toward human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) that retain or improve the antioxidant properties of capsaicin. Crystal structures of their complexes with AChE and BChE revealed the molecular basis for their high potency. Brain penetration was confirmed by biodistribution studies in C57BL6 mice, with one compound () displaying better brain/plasma ratio than donepezil.

Functional characterization of multifunctional ligands targeting acetylcholinesterase and alpha 7 nicotinic acetylcholine receptor.

Alzheimer's disease (AD) is a neurodegenerative disorder associated with cholinergic dysfunction, provoking memory loss and cognitive dysfunction in elderly patients. The cholinergic hypothesis provided over the years with molecular targets for developing palliative treatments for AD, acting on the cholinergic system, namely, acetylcholinesterase and α7 nicotinic acetylcholine receptor (α7 nAChR). In our synthetic work, we used "click-chemistry" to synthesize two Multi Target Directed Ligands (MTDLs) MB105 and MB118 carrying tacrine and quinuclidine scaffolds which are known for their anticholinesterase and α7 nAChR agonist activities, respectively.

Near-infrared emitting lanthanide(iii) complexes as prototypes of optical imaging agents with peptide targeting ability: a methodological approach.

A methodological approach to design prototypes of specific near-infrared emitting imaging agents based on a small molecular compound combining a lanthanide(iii) ion, the cyclen derivative as a coordinating unit and the azo-dye as a sensitizer with a Arg-Gly-Asp cyclopeptide as a targeting moiety, is presented here.

Increasing Polarity in Tacrine and Huprine Derivatives: Potent Anticholinesterase Agents for the Treatment of Myasthenia Gravis.

Symptomatic treatment of myasthenia gravis is based on the use of peripherally-acting acetylcholinesterase (AChE) inhibitors that, in some cases, must be discontinued due to the occurrence of a number of side-effects. Thus, new AChE inhibitors are being developed and investigated for their potential use against this disease. Here, we have explored two alternative approaches to get access to peripherally-acting AChE inhibitors as new agents against myasthenia gravis, by structural modification of the brain permeable anti-Alzheimer AChE inhibitors tacrine, 6-chlorotacrine, and huprine Y.

PET and SPECT Radiotracers for Alzheimer's Disease.

The two main pathological hallmarks of Alzheimer's disease (AD) in the brain are senile plaques (SPs) composed of beta-amyloid (Aβ) peptides and neurofibrillary tangles (NFTs) of hyperphosphorylated tau protein. These hallmarks are associated with a cholinergic deficit. While the process leading to the development of AD is complex and multifactorial, and the etiology of AD is not completely known, it is nowadays clear that AD is a multifaceted illness requiring the combination of synergetic treatment strategies.

Enantiomeric separation of original heterocyclic organophosphorus compounds in supercritical fluid chromatography.

New and original heterocyclic α-enamido phosphine chiral solutes were prepared: four structurally similar racemates with the chirality center placed on the phosphorus atom, and four other related pairs of enantiomers with chirality borne by the carbon atoms of the phospholane ring. The structural variations were placed on an aliphatic heterocycle (six- or seven-member rings) and on the carbamate function (methyl or t-butyl). Their separation was achieved on a commercial cellulose tris-(3,5-dimethylphenylcarbamate) stationary phase (Lux Cellulose-1, Phenomenex) in supercritical fluid chromatography (SFC).