478 research outputs found

    Gastarbeiter oder AuslÀnder? Ergebnisse des Splits mit den reformulierten Gastarbeiterfragen im ALLBUS 1994

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    'Die von Blank/ Schwarzer (1994) vorgeschlagene Reformulierung der Gastarbeiter-Skala aus dem ALLBUS sowie die klassischen Gastarbeiter-Items wurden in einem ALLBUS-Split 1994 erhoben. Der Aufsatz beschĂ€ftigt sich mit der Analyse der Äquivalenz beider Formulierungen in bezug auf interne und externe GĂŒltigkeit. Diese wird durch konfirmatorische Faktorenanalysen und multiple Gruppenvergleiche nachgewiesen. Die Befunde von Blank/ Schwarzer werden somit an einer reprĂ€sentativen Studie fĂŒr Gesamtdeutschland bestĂ€tigt.' (Autorenreferat)'The revision of the foreign-worker-scale of the ALLBUS suggested by Blank/ Schwarzer (1994) and the origin foreign-worker-scale were collected in an ALLBUS-split 1994. This paper is engaged with the analysis of the equivallence of the question wording effects with regard to internal and external validity. These will be demonstrated by confirmatory factor analyses and the multiple group comparison-option of LISREL. The results of Blank/ Schwarzer are confirmed in a representative study for whole Germany.' (author's abstract)

    Current Challenges to Align Inflammatory Key Events in Animals and Lung Cell Models In Vitro.

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    With numerous novel and innovative in vitro models emerging every year to reduce or replace animal testing, there is an urgent need to align the design, harmonization, and validation of such systems using in vitro-in vivo extrapolation (IVIVE) approaches. In particular, in inhalation toxicology, there is a lack of predictive and prevalidated in vitro lung models that can be considered a valid alternative for animal testing. The predictive power of such models can be enhanced by applying the Adverse Outcome Pathways (AOP) framework, which casually links key events (KE) relevant to IVIVE. However, one of the difficulties identified is that the endpoint analysis and readouts of specific assays in in vitro and animal models for specific toxicants are currently not harmonized, making the alignment challenging. We summarize the current state of the art in endpoint analysis in the two systems, focusing on inflammatory-induced effects and providing guidance for future research directions to improve the alignment

    Staphylococcal Superantigen (TSST-1) Mutant Analysis Reveals that T Cell Activation Is Required for Biological Effects in the Rabbit Including the Cytokine Storm

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    Staphylococcal superantigens (sAgs), such as toxic shock syndrome toxin 1 (TSST-1), induce massive cytokine production, which may result in toxic shock syndrome (TSS) and sepsis. Recently, we reported that in vitro studies in human peripheral blood mononuclear cells (PBMC) do not reflect the immunological situation of the host, because after exposure to superantigens (sAgs) in vivo, mononuclear cells (MNC) leave the circulation and migrate to organs, e.g., the spleen, liver and lung. Our experimental model of choice is the rabbit because it is comparable to humans in its sensitivity to sAg. T cell activation has been assessed by lymphocyte proliferation and IL-2 gene expression after in vivo challenge with TSST-1 and the mutant antigens; expression of the genes of proinflammatory cytokines were taken as indicators for the inflammatory reaction after the combined treatment with TSST-1 and LPS. The question as to whether the biological activities of TSST-1, e.g., lymphocyte extravasation, toxicity and increased sensitivity to LPS, are mediated by T cell activation or activation by MHC II-only, are unresolved and results are contradictory. We have addressed this question by studying these reactions in vivo, with two TSST-1 mutants: one mutated at the MHC binding site (G31R) with reduced MHC binding with residual activity still present, and the other at the T cell binding site (H135A) with no residual function detectable. Here, we report that the mutant G31R induced all the biological effects of the wild type sAg, while the mutant with non-functional TCR binding did not retain any of the toxic effects, proving the pivotal role of T cells in this system

    Selective Phosphorylation Modulates the PIP2 Sensitivity of the CaM-SK Channel Complex

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    Phosphatidylinositol bisphosphate (PIP2) regulates the activities of many membrane proteins including ion channels through direct interactions. However, the affinity of PIP2 is so high for some channel proteins that its physiological role as a modulator has been questioned. Here we show that PIP2 is an important cofactor for activation of small conductance Ca2+-activated potassium channels (SK) by Ca2+-bound calmodulin (CaM). Removal of the endogenous PIP2 inhibits SK channels. The PIP2-binding site resides at the interface of CaM and the SK C-terminus. We further demonstrate that the affinity of PIP2 for its target proteins can be regulated by cellular signaling. Phosphorylation of CaM T79, located adjacent to the PIP2-binding site, by Casein Kinase 2 reduces the affinity of PIP2 for the CaM-SK channel complex by altering the dynamic interactions among amino acid residues surrounding the PIP2-binding site. This effect of CaM phosphorylation promotes greater channel inhibition by G-protein-mediated hydrolysis of PIP2

    Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb−1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K−\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1 MeV,m(Ξc(2939)0)=2938.5±0.9±2.3 MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5 MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5 MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K−\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8 σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5 MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8 MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0→Λc+K−\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7 σ3.7\,\sigma. The relative branching fraction of B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the B−→D+D−K−B^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D∗)≡B(Bˉ→D∗τ−Μˉτ)/B(Bˉ→D∗Ό−ΜˉΌ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)≡B(B−→D0τ−Μˉτ)/B(B−→D0Ό−ΜˉΌ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb−1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ−→Ό−ΜτΜˉΌ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D∗)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=−0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Padroniza??o de um paradigma comportamental de esquiva inibit?ria para Zebrafish (Danio rerio Hamilton, 1822)

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    Made available in DSpace on 2015-04-14T14:50:57Z (GMT). No. of bitstreams: 1 416169.pdf: 1529649 bytes, checksum: 8c095797ae251585e66c0abd34901a5c (MD5) Previous issue date: 2009-08-25Mem?rias s?o armazenadas como modifica??es estruturais e funcionais das conex?es sin?pticas nas regi?es neurais envolvidas no aprendizado e, por sua relev?ncia biol?gica e rela??o com patologias do sistema nervoso humanas, a busca pela elucida??o dos mecanismos respons?veis por sua manuten??o tem recebido interesse de distintas ?reas do conhecimento ao longo dos anos. Estudos sobre os mecanismos neurais das mem?rias de longa dura??o demonstraram que sua forma??o ? um processo gradual que envolve substratos neuroanat?micos e celulares agora conhecidos em grande extens?o, e cujas bases moleculares s?o alvo de intensa investiga??o. O peixe tele?steo zebrafish ? um excelente modelo animal para estudos gen?ticos e de desenvolvimento e v?m mostrando enorme potencial para estudos de aprendizagem e mem?ria. Este vertebrado de f?cil manipula??o apresenta r?pido desenvolvimento externo e manuten??o pr?tica e econ?mica. Em termos neuroanat?micos, apesar das diferen?as entre aspectos do desenvolvimento e resultante disposi??o de regi?es cerebrais de mam?feros e tele?steos, a organiza??o geral do enc?falo do zebrafish segue padr?es t?picos dos vertebrados. Avan?os recentes no conhecimento demonstram que h? uma extensa similaridade, tanto em complexidade quanto em funcionamento entre o c?rebro de peixes tele?steos e os vertebrados terrestres o que valida o uso deste modelo animal para estudo dos mecanismos conservados do aprendizado e mem?ria. Embora j? existam na literatura cient?fica estudos avaliando par?metros comportamentais do zebrafish, na maior parte das vezes o foco principal dos trabalhos n?o ? a cogni??o. Aspectos como locomo??o e explora??o do ambiente s?o tomadas como medidas e os trabalhos publicados n?o mostram const?ncia em rela??o ?s tarefas utilizadas e protocolos adotados. Este trabalho teve como objetivo o desenvolvimento de um novo paradigma de esquiva inibit?ria para zebrafish a fim de permitir a avalia??o dos mecanismos celulares e moleculares da forma??o de mem?ria em vertebrados. Para tanto, o treino consistiu de apenas uma sess?o onde os animais foram colocados individualmente no aqu?rio de esquiva inibit?ria. Ao cruzar para o lado escuro do aqu?rio um choque el?trico foi administrado por 5s e estes animais retirados imediatamente do aqu?rio. Na sess?o de teste, realizada 24 h depois, seguiu-se o mesmo protocolo, por?m nenhum choque foi utilizado. As lat?ncias de entrada no lado escuro para o treino e o teste foram consideradas como indicadoras de reten??o. Para a valida??o da tarefa um grupo de animais foi tratado durante 15 min p?s-treino com o antagonista de receptor NMDA MK-801 numa concentra??o de 20 μM. Os resultados obtidos demonstram que a tarefa de esquiva inibit?ria desenvolvida para zebrafish ? baseada em mecanismos conservados em que o aprendizado, e resultante mem?ria, s?o dependentes de sinaliza??o glutamat?rgica mediada por NMDA, assim como j? evidenciado para outros vertebrados. A tarefa desenvolvida ? r?pida, simples e resulta em um aprendizado robusto, s?lido e persistente, representando um instrumento valioso para se caracterizar diferentes processos que afetam o comportamento no zebrafish, bem como permitir a disseca??o dos eventos tempos-dependentes da forma??o de mem?rias de vertebrados
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