41 research outputs found
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Subcellular optogenetic inhibition of G proteins generates signaling gradients and cell migration
Cells sense gradients of extracellular cues and generate polarized responses such as cell migration and neurite initiation. There is static information on the intracellular signaling molecules involved in these responses, but how they dynamically orchestrate polarized cell behaviors is not well understood. A limitation has been the lack of methods to exert spatial and temporal control over specific signaling molecules inside a living cell. Here we introduce optogenetic tools that act downstream of native G protein–coupled receptor (GPCRs) and provide direct control over the activity of endogenous heterotrimeric G protein subunits. Light-triggered recruitment of a truncated regulator of G protein signaling (RGS) protein or a Gβγ-sequestering domain to a selected region on the plasma membrane results in localized inhibition of G protein signaling. In immune cells exposed to spatially uniform chemoattractants, these optogenetic tools allow us to create reversible gradients of signaling activity. Migratory responses generated by this approach show that a gradient of active G protein αi and βγ subunits is sufficient to generate directed cell migration. They also provide the most direct evidence so for a global inhibition pathway triggered by Gi signaling in directional sensing and adaptation. These optogenetic tools can be applied to interrogate the mechanistic basis of other GPCR-modulated cellular functions
Long-Term Effects of the Periconception Period on Embryo Epigenetic Profile and Phenotype: The Role of Stress and How This Effect Is Mediated
Stress represents an unavoidable aspect of human life, and pathologies associated with dysregulation of stress mechanisms - particularly psychiatric disorders - represent a significant global health problem. While it has long been observed that levels of stress experienced in the periconception period may greatly affect the offspring's risk of psychiatric disorders, the mechanisms underlying these associations are not yet comprehensively understood. In order to address this question, this chapter will take a 'top-down' approach, by first defining stress and associated concepts, before exploring the mechanistic basis of the stress response in the form of the hypothalamic-pituitary-adrenal (HPA) axis, and how dysregulation of the HPA axis can impede our mental and physical health, primarily via imbalances in glucocorticoids (GCs) and their corresponding receptors (GRs) in the brain. The current extent of knowledge pertaining to the impact of stress on developmental programming and epigenetic inheritance is then extensively discussed, including the role of chromatin remodelling associated with specific HPA axis-related genes and the possible role of regulatory RNAs as messengers of environmental stress both in the intrauterine environment and across the germ line. Furthering our understanding of the role of stress on embryonic development is crucial if we are to increase our predictive power of disease risk and devise-effective treatments and intervention strategies
Identifying variation in resistance to the take-all fungus, Gaeumannomyces graminis var. tritici, between different ancestral and modern wheat species
Background: Ancestral wheat relatives are important sources of genetic diversity for the introduction of novel traits
for the improvement of modern bread wheat. In this study the aim was to assess the susceptibility of 34 accessions
of the diploid wheat Triticum monococcum (A genome) to Gaeumannomyces graminis var. tritici (Ggt), the causal
agent of take-all disease. The second aim was to explore the susceptibility of tetraploid wheat (T. durum) and the B
genome progenitor species Aegilops speltoides to Ggt.
Results: Field trials, conducted over 5 years, identified seven T. monococcum accessions with a good level of
resistance to take-all when exposed to natural inoculum under UK field conditions. All other accessions were highly
susceptible or did not exhibit a consistent phenotype across years. DArT marker genotyping revealed that whole
genome diversity was not closely related to resistance to take-all within T. monococcum, suggesting that multiple
genetic sources of resistance may exist within the species. In contrast the tetraploid wheat cultivars and Ae. speltoides
were all highly susceptible to the disease, including those with known elevated levels of benzoxazinoids.
Conclusions: The diploid wheat species T. monococcum may provide a genetic source of resistance to take-all disease
that could be utilised to improve the performance of T. aestivum in high disease risk situations. This represents an
extremely valuable resource to achieve economic and sustainable genetic control of this root disease
The kinetics of the 2 pi+2 pi photodimerisation reactions of single-crystalline derivatives of trans-cinnamic acid: A study by infrared micro spectroscopy
An in situ time-dependent study of the Photodimerisation of chloro-derivatives of trans-cinnamic acid using infrared microspectroscopy with a synchrotron radiation source
The experiences of students with learning disabilities in a higher education virtual campus
Cannabis Exposure During Critical Windows of Development: Epigenetic and Molecular Pathways Implicated in Neuropsychiatric Disease
Regulatory Role of MicroRNAs in Brain Development and Function
MicroRNAs (miRNAs) are small non-coding RNA molecules of about 20–22 nucleotides. After their posttranscriptional maturation, miRNAs are loaded into the ribonucleoprotein complex RISC and modulate gene expression by binding to the 3′ untranslated region of their target mRNAs through base-pairing, which in turn triggers mRNA degradation or translational inhibition. There is mounting evidence that miRNAs regulate various biological processes, including cell proliferation, differentiation, and apoptosis. Several studies have shown that miRNAs play an important role in neurogenesis and brain development. This review discusses recent progress on understanding the implication of precisely regulated miRNA expression in normal brain development and function. In addition, it reports known cases of dysregulation of miRNA expression and function implicated in the pathogenesis of neurodevelopmental disorders, craniofacial dysmorphic syndromes, neurodegenerative diseases, and psychiatric disorders. Current knowledge regarding the role of miRNAs in the brain in conjunction with the complex interplay between genetic and epigenetic factors are discussed. © Springer Nature Switzerland AG 2020