Polysiloxanes with Luminescent Molecular Probes : Synthesis, Characterization and Application of Ordered and Non-Ordered Structures

Katalyse in Interphasen verknüpft die Vorteile der homogenen und heterogenen Katalyse wie beispielsweise kontrollierte Umsätze und Selektivität, sowie die einfache Rückgewinnung der Katalysatoren. Unter Interphasen versteht man Systeme, bestehend aus einer stationären und mobilen Phase, die sich auf molekularer Ebene durchdringen ohne eine homogene Phase zu bilden. Ideale Interphasen gewährleisten eine hohe Mobilität des reaktiven Zentrums ähnlich einer Lösung. Die Vorteile von Polysiloxanen als stationäre Phasen einer Interphase sind die hohe Varianz der darstellbaren Trägermaterialien, durch die Wahl von unterschiedlichen Silanen oder Katalysatoren. Die Katalysatordichte ist leicht steuerbar. Werden mittels Sol-Gel Prozess Sondenmoleküle an solchen Trägermaterialien immobilisiert, kann man mit diesen Lumineszenzsonden als Modellsysteme für Katalysatoren Mobilitäts- und Zugänglichkeitsstudien unter Zuhilfenahme von UV/VIS Spektroskopie betreiben. Diese Studien erlauben es, den Einfluss der Mikroumgebung auf die Sondenmoleküle zu charakterisieren. Die Rotationsbeweglichkeit von immobilisierten Fluoren-Molekülen wurde mittels stationärer- und zeitaufgelöster Fluoreszenz-Spektroskopie bestimmt. An immobilisierten, lumineszierenden Rutheniumpolypyridyl- Komplexen wurde die Zugänglichkeit von reaktiven Zentren charakterisiert. Dies wurde durch die Lumineszenzlöschung des Rutheniumskomplexes unter Einwirkung von Sauerstoff oder Anthracen zeitaufgelöst untersucht.Catalysis in interphases combines the advantages of homogeneous and heterogeneous catalysis like the control of conversion and selectivity to desired products and the recycling of the catalyst. Interphases are systems in which a stationary phase and a mobile component penetrate each other on a molecular level without forming a homogeneous phase. In an ideal interphase the reactive centers remain highly mobile and simulate properties of a solution. The edge of sol-gel materials (polysiloxanes) used to form such an interphase, is the high range of variations which can be attained by the use of several silane monomers and the variation of the catalyst. The density of reactive centers is easily controllable. On sol-gel materials attached fluorophores serve as a model system for covalently attached catalysts, which are non-luminescent. In order to analyze the mobility and accessibility of in very low concentrations covaltently attached fluorophores fluorescence spectroscopy is a powerful tool. The method is profitably used to get new informations about the microenvironment of the fluorophores. It is thus helpful to find polymers with favorable characteristics for catalysis in interphases where small concentrations of catalysts are used and high mobility and accessibility of the catalyst is necessary. The influence of the polymer backbone and the behavior of the fluorophores can be noticed. The rotational mobility behavior of covalently attached fluorene in different non-ordered sol-gel polymers is investigated by the use of steady state and time resolved fluorescence measurements. The use of an covalently attached luminescent ruthenium complex gives more detailed prediction of non-ordered sol-gel polymers concerning the translational mobility of oxygen and anthracene by the reduced metal complex luminescence. These informations were obtained by the use of time resolved luminescence measurements

Inorganic–organic nanocomposites of CdSe nanocrystals surface-modified with oligo- and poly(fluorene) moieties

We report a facile grafting-from strategy towards the synthesis of inorganic–organic composites of semiconductor nanocrystals and wide-bandgap polymers. Amino-functional fluorenes have been used as co-ligands for CdSe nanocrystals, thus enabling us to design their surface directly during the synthesis. Highly monodisperse, strongly emitting CdSe nanocrystals have been obtained. Subsequently, a straightforward Yamamoto C–C coupling protocol was used to carry out surface polymerisation, hence modifying CdSe nanocrystals with oligo- and poly(fluorene) moieties. Both amino-fluorene capped CdSe nanocrystals and the resulting nanocrystal–polymer composites were characterized in detail by optical and FT-IR spectroscopy, TEM, AFM, and gel permeation chromatography, showing their potential as novel functional inorganic–organic hybrid materials

Oxygen and temperature sensitivity of blue to green to yellow light-emitting Pt(II) complexes

The synthesis and photophysical properties of a series of yellow-green to blue-green emitting heteroleptic, cyclometalated Pt(II)(acac) complexes based on substituted phenylpyridine and tetrahydroquinoline ligands is reported. The luminescence intensities and lifetimes of these compounds were also studied in poly(styrene) films with respect to their responses to oxygen and temperature. Particularly, due to the insensitivity to oxygen quenching, these complexes are promising candidates as inert reference dyes in optical sensors. On the other hand, the Pt(II) complex with 2-(4-bromophenyl)-5,6,7,8-tetrahydroquinoline as C^N ligand, displays a strong temperature quenching effect. The distinct response to temperature was additionally calibrated after incorporation in poly(vinylidene chloride-co-acrylonitrile) serving as oxygen-blocking matrix copolymer. The resulting yellow-green-emitting temperature sensor signifies an interesting alternative to the available mostly red emitting temperature-sensitive probes

Pathogenic <i>NR2F1</i> variants cause a developmental ocular phenotype recapitulated in a mutant mouse model.

Funder: National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of OphthalmologyPathogenic NR2F1 variants cause a rare autosomal dominant neurodevelopmental disorder referred to as the Bosch-Boonstra-Schaaf Optic Atrophy Syndrome. Although visual loss is a prominent feature seen in affected individuals, the molecular and cellular mechanisms contributing to visual impairment are still poorly characterized. We conducted a deep phenotyping study on a cohort of 22 individuals carrying pathogenic NR2F1 variants to document the neurodevelopmental and ophthalmological manifestations, in particular the structural and functional changes within the retina and the optic nerve, which have not been detailed previously. The visual impairment became apparent in early childhood with small and/or tilted hypoplastic optic nerves observed in 10 cases. High-resolution optical coherence tomography imaging confirmed significant loss of retinal ganglion cells with thinning of the ganglion cell layer, consistent with electrophysiological evidence of retinal ganglion cells dysfunction. Interestingly, for those individuals with available longitudinal ophthalmological data, there was no significant deterioration in visual function during the period of follow-up. Diffusion tensor imaging tractography studies showed defective connections and disorganization of the extracortical visual pathways. To further investigate how pathogenic NR2F1 variants impact on retinal and optic nerve development, we took advantage of an Nr2f1 mutant mouse disease model. Abnormal retinogenesis in early stages of development was observed in Nr2f1 mutant mice with decreased retinal ganglion cell density and disruption of retinal ganglion cell axonal guidance from the neural retina into the optic stalk, accounting for the development of optic nerve hypoplasia. The mutant mice showed significantly reduced visual acuity based on electrophysiological parameters with marked conduction delay and decreased amplitude of the recordings in the superficial layers of the visual cortex. The clinical observations in our study cohort, supported by the mouse data, suggest an early neurodevelopmental origin for the retinal and optic nerve head defects caused by NR2F1 pathogenic variants, resulting in congenital vision loss that seems to be non-progressive. We propose NR2F1 as a major gene that orchestrates early retinal and optic nerve head development, playing a key role in the maturation of the visual system

Pathogenic NR2F1 variants cause a developmental ocular phenotype recapitulated in a mutant mouse model.

Pathogenic NR2F1 variants cause a rare autosomal dominant neurodevelopmental disorder referred to as the Bosch-Boonstra-Schaaf Optic Atrophy Syndrome. Although visual loss is a prominent feature seen in affected individuals, the molecular and cellular mechanisms contributing to visual impairment are still poorly characterized. We conducted a deep phenotyping study on a cohort of 22 individuals carrying pathogenic NR2F1 variants to document the neurodevelopmental and ophthalmological manifestations, in particular the structural and functional changes within the retina and the optic nerve, which have not been detailed previously. The visual impairment became apparent in early childhood with small and/or tilted hypoplastic optic nerves observed in 10 cases. High-resolution optical coherence tomography imaging confirmed significant loss of retinal ganglion cells with thinning of the ganglion cell layer, consistent with electrophysiological evidence of retinal ganglion cells dysfunction. Interestingly, for those individuals with available longitudinal ophthalmological data, there was no significant deterioration in visual function during the period of follow-up. Diffusion tensor imaging tractography studies showed defective connections and disorganization of the extracortical visual pathways. To further investigate how pathogenic NR2F1 variants impact on retinal and optic nerve development, we took advantage of an Nr2f1 mutant mouse disease model. Abnormal retinogenesis in early stages of development was observed in Nr2f1 mutant mice with decreased retinal ganglion cell density and disruption of retinal ganglion cell axonal guidance from the neural retina into the optic stalk, accounting for the development of optic nerve hypoplasia. The mutant mice showed significantly reduced visual acuity based on electrophysiological parameters with marked conduction delay and decreased amplitude of the recordings in the superficial layers of the visual cortex. The clinical observations in our study cohort, supported by the mouse data, suggest an early neurodevelopmental origin for the retinal and optic nerve head defects caused by NR2F1 pathogenic variants, resulting in congenital vision loss that seems to be non-progressive. We propose NR2F1 as a major gene that orchestrates early retinal and optic nerve head development, playing a key role in the maturation of the visual system

Comprehensive Rare Variant Analysis via Whole-Genome Sequencing to Determine the Molecular Pathology of Inherited Retinal Disease

Inherited retinal disease is a common cause of visual impairment and represents a highly heterogeneous group of conditions. Here, we present findings from a cohort of 722 individuals with inherited retinal disease, who have had whole-genome sequencing (n = 605), whole-exome sequencing (n = 72), or both (n = 45) performed, as part of the NIHR-BioResource Rare Diseases research study. We identified pathogenic variants (single-nucleotide variants, indels, or structural variants) for 404/722 (56%) individuals. Whole-genome sequencing gives unprecedented power to detect three categories of pathogenic variants in particular: structural variants, variants in GC-rich regions, which have significantly improved coverage compared to whole-exome sequencing, and variants in non-coding regulatory regions. In addition to previously reported pathogenic regulatory variants, we have identified a previously unreported pathogenic intronic variant in $\textit{CHM}$ in two males with choroideremia. We have also identified 19 genes not previously known to be associated with inherited retinal disease, which harbor biallelic predicted protein-truncating variants in unsolved cases. Whole-genome sequencing is an increasingly important comprehensive method with which to investigate the genetic causes of inherited retinal disease.This work was supported by The National Institute for Health Research England (NIHR) for the NIHR BioResource – Rare Diseases project (grant number RG65966). The Moorfields Eye Hospital cohort of patients and clinical and imaging data were ascertained and collected with the support of grants from the National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital, National Health Service Foundation Trust, and UCL Institute of Ophthalmology, Moorfields Eye Hospital Special Trustees, Moorfields Eye Charity, the Foundation Fighting Blindness (USA), and Retinitis Pigmentosa Fighting Blindness. M.M. is a recipient of an FFB Career Development Award. E.M. is supported by UCLH/UCL NIHR Biomedical Research Centre. F.L.R. and D.G. are supported by Cambridge NIHR Biomedical Research Centre

Phenotypic Characterization of EIF2AK4 Mutation Carriers in a Large Cohort of Patients Diagnosed Clinically With Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease with an emerging genetic basis. Heterozygous mutations in the gene encoding the bone morphogenetic protein receptor type 2 (BMPR2) are the commonest genetic cause of PAH, whereas biallelic mutations in the eukaryotic translation initiation factor 2 alpha kinase 4 gene (EIF2AK4) are described in pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Here, we determine the frequency of these mutations and define the genotype-phenotype characteristics in a large cohort of patients diagnosed clinically with PAH. METHODS: Whole-genome sequencing was performed on DNA from patients with idiopathic and heritable PAH and with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis recruited to the National Institute of Health Research BioResource-Rare Diseases study. Heterozygous variants in BMPR2 and biallelic EIF2AK4 variants with a minor allele frequency of <1:10 000 in control data sets and predicted to be deleterious (by combined annotation-dependent depletion, PolyPhen-2, and sorting intolerant from tolerant predictions) were identified as potentially causal. Phenotype data from the time of diagnosis were also captured. RESULTS: Eight hundred sixty-four patients with idiopathic or heritable PAH and 16 with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis were recruited. Mutations in BMPR2 were identified in 130 patients (14.8%). Biallelic mutations in EIF2AK4 were identified in 5 patients with a clinical diagnosis of pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Furthermore, 9 patients with a clinical diagnosis of PAH carried biallelic EIF2AK4 mutations. These patients had a reduced transfer coefficient for carbon monoxide (Kco; 33% [interquartile range, 30%-35%] predicted) and younger age at diagnosis (29 years; interquartile range, 23-38 years) and more interlobular septal thickening and mediastinal lymphadenopathy on computed tomography of the chest compared with patients with PAH without EIF2AK4 mutations. However, radiological assessment alone could not accurately identify biallelic EIF2AK4 mutation carriers. Patients with PAH with biallelic EIF2AK4 mutations had a shorter survival. CONCLUSIONS: Biallelic EIF2AK4 mutations are found in patients classified clinically as having idiopathic and heritable PAH. These patients cannot be identified reliably by computed tomography, but a low Kco and a young age at diagnosis suggests the underlying molecular diagnosis. Genetic testing can identify these misclassified patients, allowing appropriate management and early referral for lung transplantation

Prevalence and architecture of de novo mutations in developmental disorders.

The genomes of individuals with severe, undiagnosed developmental disorders are enriched in damaging de novo mutations (DNMs) in developmentally important genes. Here we have sequenced the exomes of 4,293 families containing individuals with developmental disorders, and meta-analysed these data with data from another 3,287 individuals with similar disorders. We show that the most important factors influencing the diagnostic yield of DNMs are the sex of the affected individual, the relatedness of their parents, whether close relatives are affected and the parental ages. We identified 94 genes enriched in damaging DNMs, including 14 that previously lacked compelling evidence of involvement in developmental disorders. We have also characterized the phenotypic diversity among these disorders. We estimate that 42% of our cohort carry pathogenic DNMs in coding sequences; approximately half of these DNMs disrupt gene function and the remainder result in altered protein function. We estimate that developmental disorders caused by DNMs have an average prevalence of 1 in 213 to 1 in 448 births, depending on parental age. Given current global demographics, this equates to almost 400,000 children born per year