51 research outputs found
Mitochondrial fission factor (MFF) frameshift variant in Bullmastiffs with mitochondrial fission encephalopathy.
Familial cerebellar ataxia with hydrocephalus in Bullmastiffs was described almost 40 years ago as a monogenic autosomal recessive trait. We investigated two young Bullmastiffs showing similar clinical signs. They developed progressive gait and behavioural abnormalities with an onset at around 6 months of age. Neurological assessment was consistent with a multifocal brain disease. Magnetic resonance imaging of the brain showed intra-axial bilateral symmetrical focal lesions localised to the cerebellar nuclei. Based on the juvenile age, nature of neurological deficits and imaging findings, an inherited disorder of the brain was suspected. We sequenced the genome of one affected Bullmastiff. The data were compared with 782 control genomes of dogs from diverse breeds. This search revealed a private homozygous frameshift variant in the MFF gene in the affected dog, XM_038574000.1:c.471_475delinsCGCTCT, that is predicted to truncate 55% of the wild type MFF open reading frame, XP_038429928.1: p.(Glu158Alafs*14). Human patients with pathogenic MFF variants suffer from 'encephalopathy due to defective mitochondrial and peroxisomal fission 2'. Archived samples from two additional affected Bullmastiffs related to the originally described cases were obtained. Genotypes in a cohort of four affected and 70 unaffected Bullmastiffs showed perfect segregation with the disease phenotype. The available data together with information from previous disease reports allow classification of the investigated MFF frameshift variant as pathogenic and probably causative defect of the observed neurological phenotype. In analogy to the human phenotype, we propose to rename this disease 'mitochondrial fission encephalopathy (MFE)'
Scalable photonic integrated circuits for programmable control of atomic systems
Advances in laser technology have driven discoveries in atomic, molecular,
and optical (AMO) physics and emerging applications, from quantum computers
with cold atoms or ions, to quantum networks with solid-state color centers.
This progress is motivating the development of a new generation of
"programmable optical control" systems, characterized by criteria (C1) visible
(VIS) and near-infrared (IR) wavelength operation, (C2) large channel counts
extensible beyond 1000s of individually addressable atoms, (C3) high intensity
modulation extinction and (C4) repeatability compatible with low gate errors,
and (C5) fast switching times. Here, we address these challenges by introducing
an atom control architecture based on VIS-IR photonic integrated circuit (PIC)
technology. Based on a complementary metal-oxide-semiconductor (CMOS)
fabrication process, this Atom-control PIC (APIC) technology meets the system
requirements (C1)-(C5). As a proof of concept, we demonstrate a 16-channel
silicon nitride based APIC with (5.80.4) ns response times and -30 dB
extinction ratio at a wavelength of 780 nm. This work demonstrates the
suitability of PIC technology for quantum control, opening a path towards
scalable quantum information processing based on optically-programmable atomic
systems
A full degree-of-freedom photonic crystal spatial light modulator
Harnessing the full complexity of optical fields requires complete control of
all degrees-of-freedom within a region of space and time -- an open goal for
present-day spatial light modulators (SLMs), active metasurfaces, and optical
phased arrays. Here, we solve this challenge with a programmable photonic
crystal cavity array enabled by four key advances: (i) near-unity vertical
coupling to high-finesse microcavities through inverse design, (ii) scalable
fabrication by optimized, 300 mm full-wafer processing, (iii)
picometer-precision resonance alignment using automated, closed-loop
"holographic trimming", and (iv) out-of-plane cavity control via a high-speed
micro-LED array. Combining each, we demonstrate near-complete spatiotemporal
control of a 64-resonator, two-dimensional SLM with nanosecond- and
femtojoule-order switching. Simultaneously operating wavelength-scale modes
near the space- and time-bandwidth limits, this work opens a new regime of
programmability at the fundamental limits of multimode optical control.Comment: 25 pages, 20 figure
Hyperfine Spectroscopy of Isotopically Engineered Group-IV Color Centers in Diamond
A quantum register coupled to a spin-photon interface is a key component in
quantum communication and information processing. Group-IV color centers in
diamond (SiV, GeV, and SnV) are promising candidates for this application,
comprising an electronic spin with optical transitions coupled to a nuclear
spin as the quantum register. However, the creation of a quantum register for
these color centers with deterministic and strong coupling to the spin-photon
interface remains challenging. Here, we make first-principles predictions of
the hyperfine parameters of the group-IV color centers, which we verify
experimentally with a comprehensive comparison between the spectra of spin
active and spin neutral intrinsic dopant nuclei in single GeV and SnV emitters.
In line with the theoretical predictions, detailed spectroscopy on large sample
sizes reveals that hyperfine coupling causes a splitting of the optical
transition of SnV an order of magnitude larger than the optical linewidth and
provides a magnetic-field insensitive transition. This strong coupling provides
access to a new regime for quantum registers in diamond color centers, opening
avenues for novel spin-photon entanglement and quantum sensing schemes for
these well-studied emitters
The Protist Ribosomal Reference database (PR2): a catalog of unicellular eukaryote Small Sub-Unit rRNA sequences with curated taxonomy
International audienceThe interrogation of genetic markers in environmental meta-barcoding studies is currently seriously hindered by the lack of taxonomically curated reference data sets for the targeted genes. The Protist Ribosomal Reference database (PR2, http://ssu-rrna.org/) provides a unique access to eukaryotic small sub-unit (SSU) ribosomal RNA and DNA sequences, with curated taxonomy. The database mainly consists of nuclear-encoded protistan sequences. However, metazoans, land plants, macrosporic fungi and eukaryotic organelles (mitochondrion, plastid and others) are also included because they are useful for the analysis of high-troughput sequencing data sets. Introns and putative chimeric sequences have been also carefully checked. Taxonomic assignation of sequences consists of eight unique taxonomic fields. In total, 136 866 sequences are nuclear encoded, 45 708 (36 501 mitochondrial and 9657 chloroplastic) are from organelles, the remaining being putative chimeric sequences. The website allows the users to download sequences from the entire and partial databases (including representative sequences after clustering at a given level of similarity). Different web tools also allow searches by sequence similarity. The presence of both rRNA and rDNA sequences, taking into account introns (crucial for eukaryotic sequences), a normalized eight terms ranked-taxonomy and updates of new GenBank releases were made possible by a long-term collaboration between experts in taxonomy and computer scientists
The Protist Ribosomal Reference database (PR2): a catalog of unicellular eukaryote Small Sub-Unit rRNA sequences with curated taxonomy
The interrogation of genetic markers in environmental meta-barcoding studies is currently seriously hindered by the lack of taxonomically curated reference data sets for the targeted genes. The Protist Ribosomal Reference database (PR2, http://ssu-rrna.org/) provides a unique access to eukaryotic small sub-unit (SSU) ribosomal RNA and DNA sequences, with curated taxonomy. The database mainly consists of nuclear-encoded protistan sequences. However, metazoans, land plants, macrosporic fungi and eukaryotic organelles (mitochondrion, plastid and others) are also included because they are useful for the analysis of high-troughput sequencing data sets. Introns and putative chimeric sequences have been also carefully checked. Taxonomic assignation of sequences consists of eight unique taxonomic fields. In total, 136 866 sequences are nuclear encoded, 45 708 (36 501 mitochondrial and 9657 chloroplastic) are from organelles, the remaining being putative chimeric sequences. The website allows the users to download sequences from the entire and partial databases (including representative sequences after clustering at a given level of similarity). Different web tools also allow searches by sequence similarity. The presence of both rRNA and rDNA sequences, taking into account introns (crucial for eukaryotic sequences), a normalized eight terms ranked-taxonomy and updates of new GenBank releases were made possible by a long-term collaboration between experts in taxonomy and computer scientist
Marine protist diversity in European coastal waters and sediments as revealed by high-throughput sequencing
International audienceAlthough protists are critical components of marine ecosystems, they are still poorly characterized. Here we analysed the taxonomic diversity of planktonic and benthic protist communities collected in six distant European coastal sites. Environmental deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) from three size fractions (pico-, nano- and micro/mesoplankton), as well as from dissolved DNA and surface sediments were used as templates for tag pyrosequencing of the V4 region of the 18S ribosomal DNA. Beta-diversity analyses split the protist community structure into three main clusters: picoplankton-nanoplankton-dissolved DNA, micro/mesoplankton and sediments. Within each cluster, protist communities from the same site and time clustered together, while communities from the same site but different seasons were unrelated. Both DNA and RNA-based surveys provided similar relative abundances for most class-level taxonomic groups. Yet, particular groups were overrepresented in one of the two templates, such as marine alveolates (MALV)-I and MALV-II that were much more abundant in DNA surveys. Overall, the groups displaying the highest relative contribution were Dinophyceae, Diatomea, Ciliophora and Acantharia. Also, well represented were Mamiellophyceae, Cryptomonadales, marine alveolates and marine stramenopiles in the picoplankton, and Monadofilosa and basal Fungi in sediments. Our extensive and systematic sequencing of geographically separated sites provides the most comprehensive molecular description of coastal marine protist diversity to date
Developing a research strategy to better understand, observe, and simulate urban atmospheric processes at kilometer to subkilometer scales
A Met Office/Natural Environment Research Council Joint Weather and Climate Research Programme workshop brought together 50 key international scientists from the UK and international community to formulate the key requirements for an Urban Meteorological Research strategy. The workshop was jointly organised by University of Reading and the Met Office
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