920 research outputs found

    Epstein-Barr virus nuclear protein EBNA3C directly induces expression of AID and somatic mutations in B cells

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    Activation-induced cytidine deaminase (AID), the enzyme responsible for induction of sequence variation in immunoglobulins (Igs) during the process of somatic hypermutation (SHM) and also Ig class switching, can have a potent mutator phenotype in the development of lymphoma. Using various Epstein-Barr virus (EBV) recombinants, we provide definitive evidence that the viral nuclear protein EBNA3C is essential in EBV-infected primary B cells for the induction of AID mRNA and protein. Using lymphoblastoid cell lines (LCLs) established with EBV recombinants conditional for EBNA3C function, this was confirmed, and it was shown that transactivation of the AID gene (AICDA) is associated with EBNA3C binding to highly conserved regulatory elements located proximal to and upstream of the AICDA transcription start site. EBNA3C binding initiated epigenetic changes to chromatin at specific sites across the AICDA locus. Deep sequencing of cDNA corresponding to the IgH V-D-J region from the conditional LCL was used to formally show that SHM is activated by functional EBNA3C and induction of AID. These data, showing the direct targeting and induction of functional AID by EBNA3C, suggest a novel role for EBV in the etiology of B cell cancers, including endemic Burkitt lymphoma

    Nonperiodic inspections to guarantee a prescribed level of reliability

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    A cost-optimal nonperiodic inspection policy is derived for complex multicomponent systems. The model takes into consideration the degradation of all the components in the system with the use of a Bessel process with drift. The inspection times are determined by a deterministic function and depend on the system’s performance measure. The nonperiodic policy is developed by evaluating the expected lifetime costs and the optimal policy by an optimal choice of inspection function. The model thus gives a guaranteed level of reliability throughout the life of the project

    One-by-one trap activation in silicon nanowire transistors

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    Flicker or 1/f noise in metal-oxide-semiconductor field-effect transistors (MOSFETs) has been identified as the main source of noise at low frequency. It often originates from an ensemble of a huge number of charges trapping and detrapping. However, a deviation from the well-known model of 1/f noise is observed for nanoscale MOSFETs and a new model is required. Here, we report the observation of one-by-one trap activation controlled by the gate voltage in a nanowire MOSFET and we propose a new low-frequency-noise theory for nanoscale FETs. We demonstrate that the Coulomb repulsion between electronically charged trap sites avoids the activation of several traps simultaneously. This effect induces a noise reduction by more than one order of magnitude. It decreases when increasing the electron density in the channel due to the electrical screening of traps. These findings are technologically useful for any FETs with a short and narrow channel.Comment: One file with paper and supplementary informatio

    Nonperiodic Inspections to Guarantee a Prescribed Level of Reliability

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    Raising our sites: Dissemination of supported education

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    In order to promote replication of supported education, an exemplary rehabilitation model for adults with psychiatric disabilities, funds were accessed through a Community Action Grant from the Center for Mental Health Services of the Substance Abuse and Mental Health Services Administration. Three communities in Michigan participated in a multistage process designed to maximize community ownership by encouraging local adaptations involving all stakeholder groups and providing technical assistance. The stages in the process were organizing the community for supported education development, acquiring knowledge about supported education basics, collecting information (needs assessment and barrier identification), and developing the plan. All three sites have begun implementation, providing services to adults with psychiatric disabilities who wish to pursue post-secondary education. The approach employed has applicability for other local communities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45773/1/11414_2005_Article_BF02287778.pd

    TLR7-mediated skin inflammation remotely triggers chemokine expression and leukocyte accumulation in the brain

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    Background: The relationship between the brain and the immune system has become increasingly topical as, although it is immune-specialised, the CNS is not free from the influences of the immune system. Recent data indicate that peripheral immune stimulation can significantly affect the CNS. But the mechanisms underpinning this relationship remain unclear. The standard approach to understanding this relationship has relied on systemic immune activation using bacterial components, finding that immune mediators, such as cytokines, can have a significant effect on brain function and behaviour. More rarely have studies used disease models that are representative of human disorders. Methods: Here we use a well-characterised animal model of psoriasis-like skin inflammation—imiquimod—to investigate the effects of tissue-specific peripheral inflammation on the brain. We used full genome array, flow cytometry analysis of immune cell infiltration, doublecortin staining for neural precursor cells and a behavioural read-out exploiting natural burrowing behaviour. Results: We found that a number of genes are upregulated in the brain following treatment, amongst which is a subset of inflammatory chemokines (CCL3, CCL5, CCL9, CXCL10, CXCL13, CXCL16 and CCR5). Strikingly, this model induced the infiltration of a number of immune cell subsets into the brain parenchyma, including T cells, NK cells and myeloid cells, along with a reduction in neurogenesis and a suppression of burrowing activity. Conclusions: These findings demonstrate that cutaneous, peripheral immune stimulation is associated with significant leukocyte infiltration into the brain and suggest that chemokines may be amongst the key mediators driving this response

    Comparative analysis of long-haul system based on SSB modulation utilising dual parallel Mach–Zehnder modulators

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    In this paper, we have proposed a long-haul optical transmission system, based on a single sideband (SSB) modulation scheme. Analytical and simulation models have been developed, optimised and demonstrated for the proposed SSB system configurations. The SSB modulation scheme was proposed to overcome dispersion in the fibre. We have shown that the related link losses can be minimized by increasing the quality of the optical signal at the modulation. We have optimised the radio over fibre configuration scheme based on dual parallel dual drive Mach–Zehnder Modulator, thereby increasing transmission length of the fibre. With the proposed SSB, by suppressing some of the harmonics and cancelling one of the sidebands, we have halved the RF power fading and interference. The developed analytical (theoretical/mathematical) model agrees very well with the simulation results using two (both) different commercial simulation tools. The optical signal is boosted while minimizing the number of repeaters. We report a SSB configuration, compensation and amplification with individual spans of 150 km, by extending the length of the link up to 3250 km. The proposed system configuration exhibits high performance with less complexity and lower cost

    Visuo-tactile integration in autism: atypical temporal binding may underlie greater reliance on proprioceptive information

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    BackgroundEvidence indicates that social functioning deficits and sensory sensitivities in autism spectrum disorder (ASD) are related to atypical sensory integration. The exact mechanisms underlying these integration difficulties are unknown; however, two leading accounts are (1) an over-reliance on proprioception and (2) atypical visuo-tactile temporal binding. We directly tested these theories by selectively manipulating proprioceptive alignment and visuo-tactile synchrony to assess the extent that these impact upon body ownership.MethodsChildren with ASD and typically developing controls placed their hand into a multisensory illusion apparatus, which presented two, identical live video images of their own hand in the same plane as their actual hand. One virtual hand was aligned proprioceptively with the actual hand (the veridical hand), and the other was displaced to the left or right. While a brushstroke was applied to the participants’ actual (hidden) hand, they observed the two virtual images of their hand also being stroked and were asked to identify their real hand. During brushing, one of three different temporal delays was applied to either the displaced hand or the veridical hand. Thus, only one virtual hand had synchronous visuo-tactile inputs.ResultsResults showed that visuo-tactile synchrony overrides incongruent proprioceptive inputs in typically developing children but not in autistic children. Evidence for both temporally extended visuo-tactile binding and a greater reliance on proprioception are discussed.ConclusionsThis is the first study to provide definitive evidence for temporally extended visuo-tactile binding in ASD. This may result in reduced processing of amodal inputs (i.e. temporal synchrony) over modal-specific information (i.e. proprioception). This would likely lead to failures in appropriately binding information from related events, which would impact upon sensitivity to sensory stimuli, body representation and social processes such as empathy and imitation
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