121 research outputs found
Investigation of the Charge Symmetry Breaking Reaction ddâ4HeÏ0 with the WASA-at-COSY Facility
Probing elementary symmetries and symmetry breaking tests our understanding of the theory of strong forces, Quantum Chromodynamics. The presented study concentrates on the charge symmetry forbidden reaction ddâ4HeÏ0. The aim is to provide experimental results for comparison with predictions from Chiral Perturbation Theory (ÏPT) to study effects induced by quark masses on the hadronic level, e.g., the proton-neutron mass difference.
First calculations showed that in addition to the existing high-precision data from TRIUMF and IUCF, more data are required for a precise determination of the parameters of ÏPT. These new data should comprise the measurement of the charge symmetry forbidden ddâ4HeÏ0 reaction at sufficiently high energy, where the p-wave contribution becomes important. A first measurement with the WASA-at-COSY experiment at an excess energy of Δ = 60 MeV was performed, but the results did not allow for a decisive interpretation because of limited statistics.
This thesis reports on a second measurement of the ddâ4HeÏ0 reaction at Δ = 60 MeV using an improved WASA detector setup aiming at higher statistics. A sample of 336 ± 43 event candidates have been extracted using a data set from an eight-week long beamtime, and total and differential cross sections have been determined. The angular distribution has been described with a function of the form dÏ/dΩ = a + bcos^2Ξ*, where Ξ* is the scattering angle of the pion in the c.m. coordinate system. The obtained parameters a and b and the total cross section are:
a = (1.75 ± 0.46(stat.) +0.31-0.8(syst.)) pb/sr,
b = (13.6 ± 2.2(stat.) +0.9-2.7(syst.)) pb/sr,
Ï_tot = (79.1 ± 7.3(stat.) +1.2-10.5(syst.) ± 8.1(norm.) ± 2.0(lumi. syst.)) pb.
For this experiment a modified detector setup optimized for a time-of-flight measurement of the forward going particles has been used. After detector calibration and track reconstruction, signal events have been selected using a chain of cuts and a kinematic fit. For absolute normalization the integrated luminosity has been obtained using the ddâ3HenÏ0 reaction. The final acceptance correction has been performed using a Monte Carlo signal generator with the measured angular distribution.
The obtained differential cross section indicates the presence of higher partial waves in the final state. A combined interpretation of these results with the other measurements of the ddâ4HeÏ0 reaction allowed to determine the square of the magnitude of the p-wave amplitude |C|^2 = (520 ± 290(stat.)+50-430(syst.)) pb/(srâ(GeV/c)^2) and the real part of the s-d interference term Re(A0*A2) = (1670 ± 320(stat.) +80-430(syst.)) pb/(srâ(GeV/c)^2) neglecting any further initial and final state interactions. The result shows that any theoretical attempt to describe the reaction has to include, in addition to p-waves, also d-wave contributions
Deciphering the Transcriptomic Heterogeneity of Duodenal Coeliac Disease Biopsies
Coeliac disease (CD) is a clinically heterogeneous autoimmune disease with variable presentation
and progression triggered by gluten intake. Molecular or genetic factors contribute to disease
heterogeneity, but the reasons for different outcomes are poorly understood. Transcriptome studies
of tissue biopsies from CD patients are scarce. Here, we present a high-resolution analysis of the
transcriptomes extracted from duodenal biopsies of 24 children and adolescents with active CD and
21 individuals without CD but with intestinal afflictions as controls. The transcriptomes of CD patients
divide into three groupsâa mixed group presenting the control cases, and CD-low and CD-high
groups referring to lower and higher levels of CD severity. Persistence of symptoms was weakly
associated with subgroup, but the highest marsh stages were present in subgroup CD-high, together
with the highest cell cycle rates as an indicator of virtually complete villous atrophy. Considerable
variation in inflammation-level between subgroups was further deciphered into immune cell types
using cell type de-convolution. Self-organizing maps portrayal was applied to provide high-resolution
landscapes of the CD-transcriptome. We find asymmetric patterns of miRNA and long non-coding
RNA and discuss the effect of epigenetic regulation. Expression of genes involved in interferon
gamma signaling represent suitable markers to distinguish CD from non-CD cases. Multiple pathways
overlay in CD biopsies in different ways, giving rise to heterogeneous transcriptional patterns,
which potentially provide information about etiology and the course of the disease
A specific structure and high richness characterize intestinal microbiota of HIVexposed seronegative individuals
Intestinal microbiota facilitates food breakdown for energy metabolism and influences the im-mune response and maintaining mucosal homeostasis. Overall, HIV infection is associated with intestinal dysbiosis and immune activation, which has been related to seroconversion in HIV-exposed individuals. However, to date, it is unclear whether microbiota dysbiosis is the cause or the effect of immune alterations and disease progression. We characterize the intestinal microbiota and determine its association with immune regulation in HIV-exposed seronegative individuals (HESN), HIV-infected progressors (HIV+), and healthy control (HC) subjects. For this, feces and blood were collected. The microbiota composition of HESN showed a significantly higher alpha and beta diversity compared to HC, but similar to HIV+. A lower Treg percentage was observed in HESN than HC and HIV+, with enrichment of the genus Butyrivibrio being characteristic of this profile. Interestingly, an increase in Succinivibrio and Prevotella and a re-duction in Bacteroides genus were observed in HESN compared to HC, which is typical of HIV-infected individuals. Thus, HESNs have a microbiota profile, similar to that observed in HIV+, most likely because HESN are cohabiting with their HIV+ partners.Intestinal microbiota facilitates food breakdown for energy metabolism and influences the im-mune response and maintaining mucosal homeostasis. Overall, HIV infection is associated with intestinal dysbiosis and immune activation, which has been related to seroconversion in HIV-exposed individuals. However, to date, it is unclear whether microbiota dysbiosis is the cause or the effect of immune alterations and disease progression. We characterize the intestinal microbiota and determine its association with immune regulation in HIV-exposed seronegative individuals (HESN), HIV-infected progressors (HIV+), and healthy control (HC) subjects. For this, feces and blood were collected. The microbiota composition of HESN showed a significantly higher alpha and beta diversity compared to HC, but similar to HIV+. A lower Treg percentage was observed in HESN than HC and HIV+, with enrichment of the genus Butyrivibrio being characteristic of this profile. Interestingly, an increase in Succinivibrio and Prevotella and a re-duction in Bacteroides genus were observed in HESN compared to HC, which is typical of HIV-infected individuals. Thus, HESNs have a microbiota profile, similar to that observed in HIV+, most likely because HESN are cohabiting with their HIV+ partners.https://scienti.minciencias.gov.co/cvlac/EnProdArticulo/query.do?cod_producto=73&cod_rh=0000157775https://scholar.google.com.co/citations?hl=en&user=VLZxl1UAAAAJCOL0112548https://orcid.org/0000-0002-7351-873
A priori procedure to establish spinodal decomposition in alloys
Spinodal decomposition can improve a number of essential properties in
materials, especially hardness. Yet, the theoretical prediction of the onset of
this phenomenon (e.g., temperature) and its microstructure (e.g., wavelength)
often requires input parameters coming from costly and time-consuming
experimental efforts, hindering rational materials optimization. Here, we
present a procedure where such parameters are not derived from experiments.
First, we calculate the spinodal temperature by modeling nucleation in the
solid solution while approaching the spinode boundary. Then, we compute the
spinodal wavelength self-consistently using a few reasonable approximations.
Our results show remarkable agreement with experiments and, for NiRh, the
calculated yield strength due to spinodal microstructures surpasses even those
of Ni-based superalloys. We believe that this procedure will accelerate the
exploration of the complex materials experiencing spinodal decomposition,
critical for their macroscopic properties.Comment: 10 pages, 4 figure
Disordered enthalpyâentropy descriptor for high-entropy ceramics discovery
The need for improved functionalities in extreme environments is fuelling interest in high-entropy ceramics1,2,3. Except for the computational discovery of high-entropy carbides, performed with the entropy-forming-ability descriptor4, most innovation has been slowly driven by experimental means1,2,3. Hence, advancement in the field needs more theoretical contributions. Here we introduce disordered enthalpyâentropy descriptor (DEED), a descriptor that captures the balance between entropy gains and enthalpy costs, allowing the correct classification of functional synthesizability of multicomponent ceramics, regardless of chemistry and structure. To make our calculations possible, we have developed a convolutional algorithm that drastically reduces computational resources. Moreover, DEED guides the experimental discovery of new single-phase high-entropy carbonitrides and borides. This work, integrated into the AFLOW computational ecosystem, provides an array of potential new candidates, ripe for experimental discoveries
Dark sectors 2016 Workshop: community report
This report, based on the Dark Sectors workshop at SLAC in April 2016,
summarizes the scientific importance of searches for dark sector dark matter
and forces at masses beneath the weak-scale, the status of this broad
international field, the important milestones motivating future exploration,
and promising experimental opportunities to reach these milestones over the
next 5-10 years
Genome-wide variant calling in reanalysis of exome sequencing data uncovered a pathogenic TUBB3 variant
Almost half of all individuals affected by intellectual disability (ID) remain undiagnosed. In the Solve-RD project, exome sequencing (ES) datasets from unresolved individuals with (syndromic) ID (n = 1,472 probands) are systematically reanalyzed, starting from raw sequencing files, followed by genome-wide variant calling and new data interpretation. This strategy led to the identification of a disease-causing de novo missense variant in TUBB3 in a girl with severe developmental delay, secondary microcephaly, brain imaging abnormalities, high hypermetropia, strabismus and short stature. Interestingly, the TUBB3 variant could only be identified through reanalysis of ES data using a genome-wide variant calling approach, despite being located in protein coding sequence. More detailed analysis revealed that the position of the variant within exon 5 of TUBB3 was not targeted by the enrichment kit, although consistent high-quality coverage was obtained at this position, resulting from nearby targets that provide off-target coverage. In the initial analysis, variant calling was restricted to the exon targets +/- 200 bases, allowing the variant to escape detection by the variant calling algorithm. This phenomenon may potentially occur more often, as we determined that 36 established ID genes have robust off-target coverage in coding sequence. Moreover, within these regions, for 17 genes (likely) pathogenic variants have been identified before. Therefore, this clinical report highlights that, although compute-intensive, performing genomewide variant calling instead of target-based calling may lead to the detection of diagnostically relevant variants that would otherwise remain unnoticed
TRIM27 Negatively Regulates NOD2 by Ubiquitination and Proteasomal Degradation
NOD2, the nucleotide-binding domain and leucine-rich repeat containing gene family (NLR) member 2 is involved in mediating antimicrobial responses. Dysfunctional NOD2 activity can lead to severe inflammatory disorders, but the regulation of NOD2 is still poorly understood. Recently, proteins of the tripartite motif (TRIM) protein family have emerged as regulators of innate immune responses by acting as E3 ubiquitin ligases. We identified TRIM27 as a new specific binding partner for NOD2. We show that NOD2 physically interacts with TRIM27 via the nucleotide-binding domain, and that NOD2 activation enhances this interaction. Dependent on functional TRIM27, ectopically expressed NOD2 is ubiquitinated with K48-linked ubiquitin chains followed by proteasomal degradation. Accordingly, TRIM27 affects NOD2-mediated pro-inflammatory responses. NOD2 mutations are linked to susceptibility to Crohns disease. We found that TRIM27 expression is increased in Crohns disease patients, underscoring a physiological role of TRIM27 in regulating NOD2 signaling. In HeLa cells, TRIM27 is partially localized in the nucleus. We revealed that ectopically expressed NOD2 can shuttle to the nucleus in a Walker A dependent manner, suggesting that NOD2 and TRIM27 might functionally cooperate in the nucleus. We conclude that TRIM27 negatively regulates NOD2-mediated signaling by degradation of NOD2 and suggest that TRIM27 could be a new target for therapeutic intervention in NOD2-associated diseases.Funding Agencies|German Research Foundation (DFG)|SFB670-NG01|Swedish Society of Medicine||Regional Research Council of South-East Sweden (FORSS)||Swedish Research Council division of Medicine||Gustav V 90th anniversary foundation||Italian Telethon Foundation||DFG|SE 1122/2-1|</p
A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing
Purpose: Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the "ClinVar low-hanging fruit" reanalysis, reasons for the failure of previous analyses, and lessons learned. Methods: Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted. Results: We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency). Conclusion: The "ClinVar low-hanging fruit" analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock.The Solve-RD project has received funding from the European Unionâs Horizon 2020 research and innovation program under grant agreement number 779257. Data were analyzed using the RD-Connect Genome-Phenome Analysis Platform, which received funding from the EU projects RD-Connect, Solve-RD, and European Joint Programme on Rare Diseases (grant numbers FP7 305444, H2020 779257, H2020 825575), Instituto de Salud Carlos III (grant numbers PT13/0001/0044, PT17/0009/0019; Instituto Nacional de BioinformĂĄtica), and ELIXIR Implementation Studies. The collaborations in this study were facilitated by the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies, one of the 24 European Reference Networks approved by the European Reference Network Board of Member States, cofunded by the European Commission. This project was supported by the Czech Ministry of Health (number 00064203) and by the Czech Ministry of Education, Youth and Sports (number - LM2018132) to M.M.S
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