230 research outputs found
Optical Properties of Vanadium in 4H Silicon Carbide for Quantum Technology
We study the optical properties of tetravalent vanadium impurities in 4H
silicon carbide (4H SiC). Emission from two crystalline sites is observed at
wavelengths of 1.28 \mum and 1.33 \mum, with optical lifetimes of 163 ns and 43
ns. Group theory and ab initio density functional supercell calculations enable
unequivocal site assignment and shed light on the spectral features of the
defects. We conclude with a brief outlook on applications in quantum photonics
A physically motivated analytical expression for the temperature dependence of the zero-field splitting of the nitrogen-vacancy center in diamond
The temperature dependence of the zero-field splitting (ZFS) between the
and levels of the nitrogen-vacancy (NV)
center's electronic ground-state spin triplet can be used as a robust nanoscale
thermometer in a broad range of environments. However, despite numerous
measurements of this dependence in different temperature ranges, to our
knowledge no analytical expression has been put forward that captures the
scaling of the ZFS of the NV center across all relevant temperatures. Here we
present a simple, analytical, and physically motivated expression for the
temperature dependence of the NV center's ZFS that matches all experimental
observations, in which the ZFS shifts in proportion to the occupation numbers
of two representative phonon modes. In contrast to prior models our expression
does not diverge outside the regions of fitting. We show that our model
quantitatively matches experimental measurements of the ZFS from 15 to 500 K in
single NV centers in ultra-pure bulk diamond, and we compare our model and
measurements to prior models and experimental data.Comment: Main text: 7 pages, 4 figures, 1 table, 44 references. Supplemental
Material: 12 pages, 5 figures, 2 tables, 23 reference
The New AM Her System RX J0704.2+6203. Northern Twin of BL Hyi
We report here on the identification and study of the optical counterpart of
the ROSAT source RX J0704.2+6203. Extensive spectral and photometric
observation showed that the object belongs to the class of magnetic Cataclysmic
Variables. We determined the orbital period of the system to be 97.27m and
estimated the strength of its magnetic field to be on the order of 20 MG. The
system was observed in both high and low states, common for its class. Other
parameters of the magnetic close binary system were estimated. The spectral and
photometric behavior of the object is similar to that of the well studied polar
BL Hyi.Comment: 9 pages, 9 figures, accepted in A&
Meta-analysis of mould and dampness exposure on asthma and allergy in eight European birth cohorts: an ENRIECO initiative
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Genome-wide association and HLA fine-mapping studies identify risk loci and genetic pathways underlying allergic rhinitis
Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis
Preparation of Active Proteins, Vaccines and Pharmaceuticals as Fine Powders using Supercritical or Near-Critical Fluids
Supercritical or near-critical fluid processes for generating microparticles have enjoyed considerable attention in the past decade or so, with good success for substances soluble in supercritical fluids or organic solvents. In this review, we survey their application to the production of protein particles. A recently developed process known as CO2-assisted nebulization with a Bubble Dryer® (CAN-BD) has been demonstrated to have broad applicability to small-molecule as well as macromolecule substances (including therapeutic proteins). The principles of CAN-BD are discussed as well as the stabilization, micronization and drying of a wide variety of materials. More detailed case studies are presented for three proteins, two of which are of therapeutic interest: anti-CD4 antibody (rheumatoid arthritis), α1-antitrypsin (cystic fibrosis and emphysema), and trypsinogen (a model enzyme). Dry powders were formed in which stability and activity are maintained and which are fine enough to be inhaled and reach the deep lung. Enhancement of apparent activity after CAN-BD processing was also observed in some formulation and processing conditions
Serum 25(OH)D concentrations and atopic diseases at age 10: results from the GINIplus and LISAplus birth cohort studies
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