Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Synthesis and study of organic fluorophores for the detection of neurodegenerative diseases

Ces travaux de thèse concernent la synthèse et l’étude des propriétés optiques de fluorophores organiques appliqués à la détection de deux biomarqueurs de la maladie d’Alzheimer : la protéine kinase C (PKC) et les fibrilles de peptides amyloïdes Aβ42. La détection de la PKC est réalisée à l’aide de dyades comprenant un émetteur de type boradiazaindacène (BODIPY) relié de manière covalente à un inhibiteur de cette enzyme. Ces composés obtenus via une synthèse multi-étape présentent des coefficients d’absorption molaires et des rendements quantiques de fluorescence en solution importants. Ces sondes ont ensuite été utilisées en cytométrie de flux par la société Amoneta Diagnostics afin de détecter la PKC en surface des globules rouges et d’évaluer le potentiel de ces sondes dans le diagnostic de la maladie d’Alzheimer par test sanguin. Pour la détection des fibrilles de peptides amyloïdes, deux séries de fluorophores de la famille des 2-(2’-hydroxyphényl)-benzoxazoles ont été étudiées. Ces molécules présentent un phénomène de transfert de proton intramoléculaire à l’état excité (ESIPT) qui leur confère des propriétés optiques remarquables, telles que d’importants déplacements de Stokes et une émission duale. Enfin, un test de détection in vitro a été mis au point. Une interaction entre ces fluorophores et les fibrilles amyloïdes a pu être observée permettant la détection de ces peptides en solution.This research concerns the synthesis and photophysical studies of organic fluorescent probes applied to the detection of two Alzheimer’s disease biomarkers: the protein kinase C and fibrils of amyloid Aβ42 peptides. PKC detection is achieved by dyads composed of boradiazaindacene dye (BODIPY) covalently linked to an inhibitor of this enzyme. These compounds afforded by a multistep synthesis display high molar absorption coefficients and quantum yields in solution. These probes were then used in flow cytometry by Amoneta Diagnostics to detect PKC on the surface of red blood cells in order to asses the potential of these molecules for the diagnostic of Alzheimer’s disease by blood test. Two series of fluorophores from the 2-(2’-hydroxyphenyl)-benzazole family have been studied for the detection of amyloid fibrils. These molecules display an excited state intramolecular proton transfer (ESIPT) phenomenon which confer them remarkable optical properties such as important Stokes shifts and dual emission. Finally, an in vitro detection test has been developed. Interactions between these dyes and amyloid fibrils has been observed, allowing the detection of these peptides in solution

Fluorine-18-Labeled Fluorescent Dyes for Dual-Mode Molecular Imaging

Recent progress realized in the development of optical imaging (OPI) probes and devices has made this technique more and more affordable for imaging studies and fluorescence-guided surgery procedures. However, this imaging modality still suffers from a low depth of penetration, thus limiting its use to shallow tissues or endoscopy-based procedures. In contrast, positron emission tomography (PET) presents a high depth of penetration and the resulting signal is less attenuated, allowing for imaging in-depth tissues. Thus, association of these imaging techniques has the potential to push back the limits of each single modality. Recently, several research groups have been involved in the development of radiolabeled fluorophores with the aim of affording dual-mode PET/OPI probes used in preclinical imaging studies of diverse pathological conditions such as cancer, Alzheimer’s disease, or cardiovascular diseases. Among all the available PET-active radionuclides, 18F stands out as the most widely used for clinical imaging thanks to its advantageous characteristics (t1/2 = 109.77 min; 97% β+ emitter). This review focuses on the recent efforts in the synthesis and radiofluorination of fluorescent scaffolds such as 4,4-difluoro-4-bora-diazaindacenes (BODIPYs), cyanines, and xanthene derivatives and their use in preclinical imaging studies using both PET and OPI technologies

Synthesis and study of organic fluorophores for the detection of neurodegenerative diseases

Ces travaux de thèse concernent la synthèse et l’étude des propriétés optiques de fluorophores organiques appliqués à la détection de deux biomarqueurs de la maladie d’Alzheimer : la protéine kinase C (PKC) et les fibrilles de peptides amyloïdes Aβ42. La détection de la PKC est réalisée à l’aide de dyades comprenant un émetteur de type boradiazaindacène (BODIPY) relié de manière covalente à un inhibiteur de cette enzyme. Ces composés obtenus via une synthèse multi-étape présentent des coefficients d’absorption molaires et des rendements quantiques de fluorescence en solution importants. Ces sondes ont ensuite été utilisées en cytométrie de flux par la société Amoneta Diagnostics afin de détecter la PKC en surface des globules rouges et d’évaluer le potentiel de ces sondes dans le diagnostic de la maladie d’Alzheimer par test sanguin. Pour la détection des fibrilles de peptides amyloïdes, deux séries de fluorophores de la famille des 2-(2’-hydroxyphényl)-benzoxazoles ont été étudiées. Ces molécules présentent un phénomène de transfert de proton intramoléculaire à l’état excité (ESIPT) qui leur confère des propriétés optiques remarquables, telles que d’importants déplacements de Stokes et une émission duale. Enfin, un test de détection in vitro a été mis au point. Une interaction entre ces fluorophores et les fibrilles amyloïdes a pu être observée permettant la détection de ces peptides en solution.This research concerns the synthesis and photophysical studies of organic fluorescent probes applied to the detection of two Alzheimer’s disease biomarkers: the protein kinase C and fibrils of amyloid Aβ42 peptides. PKC detection is achieved by dyads composed of boradiazaindacene dye (BODIPY) covalently linked to an inhibitor of this enzyme. These compounds afforded by a multistep synthesis display high molar absorption coefficients and quantum yields in solution. These probes were then used in flow cytometry by Amoneta Diagnostics to detect PKC on the surface of red blood cells in order to asses the potential of these molecules for the diagnostic of Alzheimer’s disease by blood test. Two series of fluorophores from the 2-(2’-hydroxyphenyl)-benzazole family have been studied for the detection of amyloid fibrils. These molecules display an excited state intramolecular proton transfer (ESIPT) phenomenon which confer them remarkable optical properties such as important Stokes shifts and dual emission. Finally, an in vitro detection test has been developed. Interactions between these dyes and amyloid fibrils has been observed, allowing the detection of these peptides in solution

Interrupted Aza-Wittig Reactions Using Iminophosphoranes to Synthesize 11C-Carbonyls

Iminophosphoranes are reported as convenient precursors to amides, ureas, carbamates and other carbonyl-containing molecules through CO2-fixation. Key to this transformation with stable isotopes and carbon-11 is interception of the reactive isocyanate intermediate. Automated synthesis and isolation of PET radiopharmaceuticals is achieved

Fast Carbon Isotope Exchange of Carboxylic Acids Enabled by Organic Photoredox Catalysis

Carbazole/cyanobenzene photocatalysts promote the direct isotopic carboxylate exchange of C(sp3 )-acids with labelled CO2. Substrates that are not compatible with transition metal catalyzed degradation-reconstruction approaches or prone to thermally induced reversible decarboxylation undergo isotopic incorporation at room temperature in short reaction times. The radiolabelling of drug molecules and precursors with [11C]CO2 is demonstrated

Ethynyl-Tolyl Extended 2-(2 `-Hydroxyphenyl)benzoxazole Dyes: Solution and Solid-state Excited-State Intramolecular Proton Transfer (ESIPT) Emitters

Dual solution/solid-state emissive fluorophores based on a 2-(2 `-Hydroxyphenyl)benzoxazole (HBO) core bearing one or two ethynyl-tolyl moieties at different positions were synthesized via an expedite two-step synthetic procedure. HBO derivatives are known to display intense Excited-State Intramolecular Proton Transfer (ESIPT) emission in the solid-state but are mildly emissive in solution due to the detrimental flexibility of the excited-state opening efficient non-radiative pathways. The sole introduction of a rigid ethynyl moiety led to a sizeable enhancement of the fluorescence quantum yield in solution, up to a 15-fold increase in toluene as compared to unsubstituted HBO dyes while keeping the high solid-state fluorescence efficiency. The position of the substitution on the pi-conjugated core led to subtle fine-tuning of maximum emission wavelengths and quantum yields. Moreover, we show that the ethynyl tolyl substituent at the para position of the phenol ring is a suitable moiety for an efficient stabilization of the corresponding emissive anionic HBO derivatives in dissociative solvents like DMF THF or EtOH. These observations were confirmed in CH3CN by a basic titration. For all dyes, the nature of the excited-state involved in the fluorescence emission was rationalized using ab initio calculations