118 research outputs found
Strain and correlation of self-organized Ge_(1-x)Mn_x nanocolumns embedded in Ge (001)
We report on the structural properties of Ge_(1-x)Mn_x layers grown by
molecular beam epitaxy. In these layers, nanocolumns with a high Mn content are
embedded in an almost-pure Ge matrix. We have used grazing-incidence X-ray
scattering, atomic force and transmission electron microscopy to study the
structural properties of the columns. We demonstrate how the elastic
deformation of the matrix (as calculated using atomistic simulations) around
the columns, as well as the average inter-column distance can account for the
shape of the diffusion around Bragg peaks.Comment: 9 pages, 7 figure
High-contrast quantum-confined Stark effect in Ge/SiGe quantum well stacks on Si with ultra-thin buffer layers
rBCG Induces Strong Antigen-Specific T Cell Responses in Rhesus Macaques in a Prime-Boost Setting with an Adenovirus 35 Tuberculosis Vaccine Vector
BACKGROUND: BCG vaccination, combined with adenoviral-delivered boosts, represents a reasonable strategy to augment, broaden and prolong immune protection against tuberculosis (TB). We tested BCG (SSI1331) (in 6 animals, delivered intradermally) and a recombinant (rBCG) AFRO-1 expressing perfringolysin (in 6 animals) followed by two boosts (delivered intramuscullary) with non-replicating adenovirus 35 (rAd35) expressing a fusion protein composed of Ag85A, Ag85B and TB10.4, for the capacity to induce antigen-specific cellular immune responses in rhesus macaques (Macaca mulatta). Control animals received diluent (3 animals). METHODS AND FINDINGS: Cellular immune responses were analyzed longitudinally (12 blood draws for each animal) using intracellular cytokine staining (TNF-alpha, IL-2 and IFN-gamma), T cell proliferation was measured in CD4(+), CD8alpha/beta(+), and CD8alpha/alpha(+) T cell subsets and IFN-gamma production was tested in 7 day PBMC cultures (whole blood cell assay, WBA) using Ag85A, Ag85B, TB10.4 recombinant proteins, PPD or BCG as stimuli. Animals primed with AFRO-1 showed i) increased Ag85B-specific IFN-gamma production in the WBA assay (median >400 pg/ml for 6 animals) one week after the first boost with adenoviral-delivered TB-antigens as compared to animals primed with BCG (<200 pg/ml), ii) stronger T cell proliferation in the CD8alpha/alpha(+) T cell subset (proliferative index 17%) as compared to BCG-primed animals (proliferative index 5% in CD8alpha/alpha(+) T cells). Polyfunctional T cells, defined by IFN-gamma, TNF-alpha and IL-2 production were detected in 2/6 animals primed with AFRO-1 directed against Ag85A/b and TB10.4; 4/6 animals primed with BCG showed a Ag85A/b responses, yet only a single animal exhibited Ag85A/b and TB10.4 reactivity. CONCLUSION: AFRO-1 induces qualitatively and quantitatively different cellular immune responses as compared with BCG in rhesus macaques. Increased IFN-gamma-responses and antigen-specific T cell proliferation in the CD8alpha/alpha+ T cell subset represents a valuable marker for vaccine-take in BCG-based TB vaccine trials
Thin Film (High Temperature) Superconducting Radiofrequency Cavities for the Search of Axion Dark Matter
5 pages, 6 figures. v2: minor updates after referee comments, matches
published version in IEEEThe axion is a hypothetical particle which is a candidate for cold dark
matter. Haloscope experiments directly search for these particles in strong
magnetic fields with RF cavities as detectors. The Relic Axion Detector
Exploratory Setup (RADES) at CERN in particular is searching for axion dark
matter in a mass range above 30 eV. The figure of merit of our detector
depends linearly on the quality factor of the cavity and therefore we are
researching the possibility of coating our cavities with different
superconducting materials to increase the quality factor. Since the experiment
operates in strong magnetic fields of 11 T and more, superconductors with high
critical magnetic fields are necessary. Suitable materials for this application
are for example REBaCuO, NbSn or NbN. We designed a
microwave cavity which resonates at around 9~GHz, with a geometry optimized to
facilitate superconducting coating and designed to fit in the bore of available
high-field accelerator magnets at CERN. Several prototypes of this cavity were
coated with different superconducting materials, employing different coating
techniques. These prototypes were characterized in strong magnetic fields at
4.2 K.This project has received funding from the European Unionâs Horizon 2020
Research and Innovation programme under Grant Agreement No 730871
(ARIES-TNA). BD and JG acknowledge funding through the European
Research Council under grant ERC-2018-StG-802836 (AxScale). We also
acknowledge funding via the Spanish Agencia Estatal de Investigacion (AEI)
and Fondo Europeo de Desarrollo Regional (FEDER) under project PID2019-
108122GB-C33, and the grant FPI BES-2017-079787 (under project FPA2016-76978-C3-2-P). Furthermore we acknowledge support from SuMaTe
RTI2018-095853-B-C21 from MICINN co-financed by the European Regional
Development Fund, Center of Excellence award Severo Ochoa CEX2019-
000917-S and CERN under Grant FCCGOV-CC-0208 (KE4947/ATS).With funding from the Spanish government through the âSevero Ochoa Centre of Excellenceâ accreditation (CEX2019-000917-S).Peer reviewe
Comparative genetic analysis: the utility of mouse genetic systems for studying human monogenic disease
One of the long-term goals of mutagenesis programs in the mouse has been to generate mutant lines to facilitate the functional study of every mammalian gene. With a combination of complementary genetic approaches and advances in technology, this aim is slowly becoming a reality. One of the most important features of this strategy is the ability to identify and compare a number of mutations in the same gene, an allelic series. With the advent of gene-driven screening of mutant archives, the search for a specific series of interest is now a practical option. This review focuses on the analysis of multiple mutations from chemical mutagenesis projects in a wide variety of genes and the valuable functional information that has been obtained from these studies. Although gene knockouts and transgenics will continue to be an important resource to ascertain gene function, with a significant proportion of human diseases caused by point mutations, identifying an allelic series is becoming an equally efficient route to generating clinically relevant and functionally important mouse models
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