628 research outputs found

    Coulomb Corrections for Coherent Electroproduction of Vector Mesons: Eikonal Approximation

    Get PDF
    Virtual radiative corrections due to the long range Coulomb forces of heavy nuclei with charge Z may lead to sizeable corrections to the Born cross section usually used for lepton-nucleus scattering processes. An introduction and presentation of the most important issues of the eikonal approximation is given. We present calculations for forward electroproduction production of rho mesons in a framework suggested by the VDM (vector dominance model), using the eikonal approximation. It turns out that Coulomb corrections may become relatively large. Some minor errors in the literature are corrected.Comment: 14 pages, 6 figures, published versio

    Regulation of stem cell differentiation by histone methyltransferases and demethylases

    Get PDF
    The generation of different cell types from stem cells containing identical genetic information and their organization into tissues and organs during development is a highly complex process that requires defined transcriptional programs. Maintenance of such programs is epigenetically regulated and the factors involved in these processes are often essential for development. The activities required for cell-fate decisions are frequently deregulated in human tumors, and the elucidation of the molecular mechanisms that regulate these processes is therefore important for understanding both developmental processes and tumorigenesis

    Power-controlled phase-matching and instability of CW propagation in multicore optical fibers with a central core

    Get PDF
    We present modulation instability analysis including azimuthal perturbations of steady-state continuous wave (CW) propagation in multicore-fiber configurations with a central core. In systems with a central core, a steady CW evolution regime requires power-controlled phase matching, which offers interesting spatial-division applications. Our results have general applicability and are relevant to a range of physical and engineering systems, including high-power fiber lasers, optical transmission in multicore fiber, and systems of coupled nonlinear waveguides

    A Liposome-Based Mycobacterial Vaccine Induces Potent Adult and Neonatal Multifunctional T Cells through the Exquisite Targeting of Dendritic Cells

    Get PDF
    BACKGROUND: In the search for more potent and safer tuberculosis vaccines, CAF01 was identified as a remarkable formulation. Based on cationic liposomes and including a synthetic mycobacterial glycolipid as TLR-independent immunomodulator, it induces strong and protective T helper-1 and T helper-17 adult murine responses to Ag85B-ESAT-6, a major mycobacterial fusion protein. Here, we assessed whether these properties extend to early life and how CAF01 mediates its adjuvant properties in vivo. METHODS/FINDINGS: Following adult or neonatal murine immunization, Ag85B-ESAT-6/CAF01 similarly reduced the post-challenge bacterial growth of M. bovis BCG, whereas no protection was observed using Alum as control. This protection was mediated by the induction of similarly strong Th1 and Th17 responses in both age groups. Multifunctional Th1 cells were already elicited after a single vaccine dose and persisted at high levels for at least 6 months even after neonatal priming. Unexpectedly, this potent adjuvanticity was not mediated by a massive targeting/activation of dendritic cells: in contrast, very few DCs in the draining lymph nodes were bearing the labeled antigen/adjuvant. The increased expression of the CD40 and CD86 activation markers was restricted to the minute portion of adjuvant-bearing DCs. However, vaccine-associated activated DCs were recovered several days after immunization. CONCLUSION: The potent adult and neonatal adjuvanticity of CAF01 is associated in vivo with an exquisite but prolonged DC uptake and activation, fulfilling the preclinical requirements for novel tuberculosis vaccines to be used in early life

    Digital prosumption labour on social media in the context of the capitalist regime of time

    Get PDF
    So-called social media such as Facebook, Twitter, YouTube, Weibo and LinkedIn are an expression of changing regimes of time in capitalist society. This paper discusses how corporate social media are related to the capitalist organization of time and the changes this organization is undergoing. It uses social theory for conceptualizing changes of society and its time regime and how these changes shape social media. These changes have been described with notions such as prosumption, consumption labour, play labour (playbour) and digital labour. The paper contextualizes digital labour on social media with the help of a model of society that distinguishes three subsystems (the economy, politics, culture) and three forms of power (economic, political, culture). In modern society, these systems are based on the logic of the accumulation of power and the acceleration of accumulation. The paper discusses the role of various dimensions of time in capitalism with the help of a model that is grounded in Karl Marx’s works. It points out the importance of the category of time for a labour theory of value and a digital labour theory of value. Social media are expressions of the changing time regimes that modern society has been undergoing, especially in relation to the blurring of leisure and labour time (play labour), production and consumption time (prosumption), new forms of absolute and relative surplus value production, the acceleration of consumption with the help of targeted online advertising and the creation of speculative, future-oriented forms of fictitious capital

    Emission decay and energy transfer in Yb/Tm Y-codoped fibers based on nano-modified glass

    Get PDF
    We report the results of an experimental investigation and theoretical analysis of luminescence decay in Yb/Tm Y-codoped fibers based on nano-modified glass. Based on the experimental results, numerical simulations allowed us to estimate the energy transfer efficiency between Yb3+ and Tm3+ ions. It was shown that yttria enhances the Yb/Tm energy transfer making fibers with Y-codoping a promising candidate for the development of light sources for laser applications and up-conversion emitters for visualization applications. These fibers demonstrate energy transfer efficiency of ∼50%, which makes them attractive for diode-pumping of Yb-ions at a wavelength of 975 nm

    The C. elegans H3K27 Demethylase UTX-1 Is Essential for Normal Development, Independent of Its Enzymatic Activity

    Get PDF
    Epigenetic modifications influence gene expression and provide a unique mechanism for fine-tuning cellular differentiation and development in multicellular organisms. Here we report on the biological functions of UTX-1, the Caenorhabditis elegans homologue of mammalian UTX, a histone demethylase specific for H3K27me2/3. We demonstrate that utx-1 is an essential gene that is required for correct embryonic and postembryonic development. Consistent with its homology to UTX, UTX-1 regulates global levels of H3K27me2/3 in C. elegans. Surprisingly, we found that the catalytic activity is not required for the developmental function of this protein. Biochemical analysis identified UTX-1 as a component of a complex that includes SET-16(MLL), and genetic analysis indicates that the defects associated with loss of UTX-1 are likely mediated by compromised SET-16/UTX-1 complex activity. Taken together, these results demonstrate that UTX-1 is required for many aspects of nematode development; but, unexpectedly, this function is independent of its enzymatic activity

    Occupational Therapy Intervention with Children Survivors of War

    Get PDF
    A preventive occupational therapy program with children surviving the Kosovo conflict is examined. The objective of the program was to facilitate the emotional expression of traumatic experiences in order to prevent the development of future psychological problems. The intervention was based on a community-centred approach with spirituality as a central focus of the intervention.The Model of Human Occupation and the Occupational Performance Process Model were utilized to guide the identification and intervention of occupational performance issues.The children’s return from a land of war to a land of children demonstrates the potential of occupational therapy intervention in this field. With increasing awareness of populations facing social and political challenges, there is a growing importance of the concept of occupational justice and the need to work against occupational apartheid.Cet article décrit un programme de prévention en ergothérapie qui était destiné aux enfants ayant survécu au conflit du Kosovo. L’objectif du programme était d’aider les enfants à exprimer les émotions qu’ils avaient ressenties lors d’expériences traumatiques afin de prévenir l’apparition de problèmes psychologiques. L’intervention était basée sur une approche communautaire s’articulant autour de la spiritualité. Le Modèle de l’occupation humaine et le Modèle du processus d’intervention dans le rendement occupationnel ont été utilisés pour cibler les difficultés en matière de rendement occupationnel et pour déterminer les interventions requises. Le retour des enfants d’un monde de guerre vers le monde de l’enfance démontre la possibilité de proposer une intervention ergothérapique dans ce domaine. La conscientisation de plus en plus grand face à la détresse des populations confrontées à des problèmes politiques et sociaux entraîne une augmentation de l’importance du concept de la justice occupationnelle et du besoin de lutter contre l’apartheid occupationnel

    CAF01 Potentiates Immune Responses and Efficacy of an Inactivated Influenza Vaccine in Ferrets

    Get PDF
    Trivalent inactivated vaccines (TIV) against influenza are given to 350 million people every year. Most of these are non-adjuvanted vaccines whose immunogenicity and protective efficacy are considered suboptimal. Commercially available non-adjuvanted TIV are known to elicit mainly a humoral immune response, whereas the induction of cell-mediated immune responses is negligible. Recently, a cationic liposomal adjuvant (dimethyldioctadecylammonium/trehalose 6,6′-dibehenate, CAF01) was developed. CAF01 has proven to enhance both humoral and cell-mediated immune responses to a number of different experimental vaccine candidates. In this study, we compared the immune responses in ferrets to a commercially available TIV with the responses to the same vaccine mixed with the CAF01 adjuvant. Two recently circulating H1N1 viruses were used as challenge to test the vaccine efficacy. CAF01 improved the immunogenicity of the vaccine, with increased influenza-specific IgA and IgG levels. Additionally, CAF01 promoted cellular-mediated immunity as indicated by interferon-gamma expressing lymphocytes, measured by flow cytometry. CAF01 also enhanced the protection conferred by the vaccine by reducing the viral load measured in nasal washes by RT-PCR. Finally, CAF01 allowed for dose-reduction and led to higher levels of protection compared to TIV adjuvanted with a squalene emulsion. The data obtained in this human-relevant challenge model supports the potential of CAF01 in future influenza vaccines
    • …
    corecore