544 research outputs found

    Unreality, Reality, and Themes in Kezilahabi's Rosa Mistika and Mahfouz's Midaq Alley

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    This work provides a close linguistic and thematic analysis of the dialogues in the two novels Midaq Alley by N. Mahfouz and Rosa Mistika by E. Kezilahabi, as they reflect fundamental assumptions about gender, tradition, and modernity. Certain complex clauses that have been traditionally recognized in Logic and Philosophy to be used in argument play a key role in expressing the conflicts that are central to the themes in both works. The data for this analysis come from dialogues and conversations found in the English translation of Midaq Alley and the Swahili of Rosa Mistika, specifically, simple conditionals, contrary-to-facts, and hypotheticals. The merger of Philosophy, Discourse Linguistics and Literature permits a close analysis of literature for cultural and thematic content. The pragmatic information imparted by these structures, such as speaker presuppositions, entailment, perceptions about possible fulfillment add much to the revealing of the themes that are central to the two novels: the urgent need for both societies to confront the roles of women in African societies, the tendency to favor modernity over tradition, and the implications of socio-economic inequality

    Integrin αvβ5 is a primary receptor for adenovirus in CAR-negative cells

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    <p>Abstract</p> <p>Background</p> <p>Viruses bind to specific cellular receptors in order to infect their hosts. The specific receptors a virus uses are important factors in determining host range, cellular tropism, and pathogenesis. For adenovirus, the existing model of entry requires two receptor interactions. First, the viral fiber protein binds Coxsackie and Adenovirus Receptor (CAR), its primary cellular receptor, which docks the virus to the cell surface. Next, viral penton base engages cellular integrins, coreceptors thought to be required exclusively for internalization and not contributing to binding. However, a number of studies reporting data which conflicts with this simple model have been published. These observations have led us to question the proposed two-step model for adenovirus infection.</p> <p>Results</p> <p>In this study we report that cells which express little to no CAR can be efficiently transduced by adenovirus. Using competition experiments between whole virus and soluble viral fiber protein or integrin blocking peptides, we show virus binding is not dependent on fiber binding to cells but rather on penton base binding cellular integrins. Further, we find that binding to low CAR expressing cells is inhibited specifically by a blocking antibody to integrin αvβ5, demonstrating that in these cells integrin αvβ5 and not CAR is required for adenovirus attachment. The binding mediated by integrin αvβ5 is extremely high affinity, in the picomolar range.</p> <p>Conclusions</p> <p>Our data further challenges the model of adenovirus infection in which binding to primary receptor CAR is required in order for subsequent interactions between adenovirus and integrins to initiate viral entry. In low CAR cells, binding occurs through integrin αvβ5, a receptor previously thought to be used exclusively in internalization. We show for the first time that integrin αvβ5 can be used as an alternate binding receptor.</p

    Complex chloroplast RNA metabolism: just debugging the genetic programme?

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    <p>Abstract</p> <p>Background</p> <p>The gene expression system of chloroplasts is far more complex than that of their cyanobacterial progenitor. This gain in complexity affects in particular RNA metabolism, specifically the transcription and maturation of RNA. Mature chloroplast RNA is generated by a plethora of nuclear-encoded proteins acquired or recruited during plant evolution, comprising additional RNA polymerases and sigma factors, and sequence-specific RNA maturation factors promoting RNA splicing, editing, end formation and translatability. Despite years of intensive research, we still lack a comprehensive explanation for this complexity.</p> <p>Results</p> <p>We inspected the available literature and genome databases for information on components of RNA metabolism in land plant chloroplasts. In particular, new inventions of chloroplast-specific mechanisms and the expansion of some gene/protein families detected in land plants lead us to suggest that the primary function of the additional nuclear-encoded components found in chloroplasts is the transgenomic suppression of point mutations, fixation of which occurred due to an enhanced genetic drift exhibited by chloroplast genomes. We further speculate that a fast evolution of transgenomic suppressors occurred after the water-to-land transition of plants.</p> <p>Conclusion</p> <p>Our inspections indicate that several chloroplast-specific mechanisms evolved in land plants to remedy point mutations that occurred after the water-to-land transition. Thus, the complexity of chloroplast gene expression evolved to guarantee the functionality of chloroplast genetic information and may not, with some exceptions, be involved in regulatory functions.</p

    The association between insight and depressive symptoms in schizophrenia: Undirected and Bayesian network analyses

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    Background. Greater levels of insight may be linked with depressive symptoms among patients with schizophrenia, however, it would be useful to characterize this association at symptom-level, in order to inform research on interventions. Methods. Data on depressive symptoms (Calgary Depression Scale for Schizophrenia) and insight (G12 item from the Positive and Negative Syndrome Scale) were obtained from 921 community-dwelling, clinically-stable individuals with a DSM-IV diagnosis of schizophrenia, recruited in a nationwide multicenter study. Network analysis was used to explore the most relevant connections between insight and depressive symptoms, including potential confounders in the model (neurocognitive and social-cognitive functioning, positive, negative and disorganization symptoms, extrapyramidal symptoms, hostility, internalized stigma, and perceived discrimination). Bayesian network analysis was used to estimate a directed acyclic graph (DAG) while investigating the most likely direction of the putative causal association between insight and depression. Results. After adjusting for confounders, better levels of insight were associated with greater self-depreciation, pathological guilt, morning depression and suicidal ideation. No difference in global network structure was detected for socioeconomic status, service engagement or illness severity. The DAG confirmed the presence of an association between greater insight and self-depreciation, suggesting the more probable causal direction was from insight to depressive symptoms. Conclusions. In schizophrenia, better levels of insight may cause self-depreciation and, possibly, other depressive symptoms. Person-centered and narrative psychotherapeutic approaches may be particularly fit to improve patient insight without dampening self-esteem

    Evolution of the deaminase fold and multiple origins of eukaryotic editing and mutagenic nucleic acid deaminases from bacterial toxin systems

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    The deaminase-like fold includes, in addition to nucleic acid/nucleotide deaminases, several catalytic domains such as the JAB domain, and others involved in nucleotide and ADP-ribose metabolism. Using sensitive sequence and structural comparison methods, we develop a comprehensive natural classification of the deaminase-like fold and show that its ancestral version was likely to operate on nucleotides or nucleic acids. Consequently, we present evidence that a specific group of JAB domains are likely to possess a DNA repair function, distinct from the previously known deubiquitinating peptidase activity. We also identified numerous previously unknown clades of nucleic acid deaminases. Using inference based on contextual information, we suggest that most of these clades are toxin domains of two distinct classes of bacterial toxin systems, namely polymorphic toxins implicated in bacterial interstrain competition and those that target distantly related cells. Genome context information suggests that these toxins might be delivered via diverse secretory systems, such as Type V, Type VI, PVC and a novel PrsW-like intramembrane peptidase-dependent mechanism. We propose that certain deaminase toxins might be deployed by diverse extracellular and intracellular pathogens as also endosymbionts as effectors targeting nucleic acids of host cells. Our analysis suggests that these toxin deaminases have been acquired by eukaryotes on several independent occasions and recruited as organellar or nucleo-cytoplasmic RNA modifiers, operating on tRNAs, mRNAs and short non-coding RNAs, and also as mutators of hyper-variable genes, viruses and selfish elements. This scenario potentially explains the origin of mutagenic AID/APOBEC-like deaminases, including novel versions from Caenorhabditis, Nematostella and diverse algae and a large class of fast-evolving fungal deaminases. These observations greatly expand the distribution of possible unidentified mutagenic processes catalyzed by nucleic acid deaminases

    A New Look at the Scalar Meson f0(500)f_0(500) via D+π+π+νD^+\to \pi^+\pi^-\ell^+\nu_\ell Decays

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    Using 2.93 fb12.93~\mathrm{fb}^{-1} of e+ee^+e^- collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV, we investigate the semileptonic decays D+π+π+νD^+\to \pi^+\pi^- \ell^+\nu_\ell (=e\ell=e and μ\mu). The D+f0(500)μ+νμD^+\to f_0(500)\mu^+\nu_\mu decay is observed for the first time. By analyzing simultaneously the differential decay rates of D+f0(500)μ+νμD^+\to f_0(500) \mu^+\nu_\mu and D+f0(500)e+νeD^+\to f_0(500) e^+\nu_e in different +ν\ell^+\nu_\ell four-momentum transfer intervals, the product of the relevant hadronic form factor f+f0(0)f^{f_0}_{+}(0) and the magnitude of the cdc\to d Cabibbo-Kobayashi-Maskawa matrix element Vcd|V_{cd}| is determined to be f+f0(0)Vcd=0.0787±0.0060stat±0.0033systf_{+}^{f_0} (0)|V_{cd}|=0.0787\pm0.0060_{\rm stat}\pm0.0033_{\rm syst} for the first time. With the input of Vcd|V_{cd}| from the global fit in the standard model, we determine f+f0(0)=0.350±0.027stat±0.015systf_{+}^{f_0} (0)=0.350\pm0.027_{\rm stat}\pm0.015_{\rm syst}. The absolute branching fractions of D+f0(500)(π+π)μ+νμD^+\to f_0(500)_{(\pi^+\pi^-)}\mu^+\nu_\mu and D+ρ(π+π)0μ+νμD^+\to \rho^0_{(\pi^+\pi^-)} \mu^+\nu_\mu are determined as (0.72±0.13stat±0.10syst)×103(0.72\pm0.13_{\rm stat}\pm0.10_{\rm syst})\times10^{-3} and (1.64±0.13stat±0.11syst)×103(1.64\pm0.13_{\rm stat}\pm0.11_{\rm syst})\times 10^{-3}. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios BD+ρ0μ+νμ/BD+ρ0e+νe=0.88±0.10{\mathcal B}_{D^+\to \rho^0 \mu^+\nu_\mu}/{\mathcal B}_{D^+\to \rho^0 e^+\nu_e}=0.88\pm0.10 and BD+f0(500)μ+νμ/BD+f0(500)e+νe=1.14±0.28{\mathcal B}_{D^+\to f_0(500) \mu^+\nu_\mu}/{\mathcal B}_{D^+\to f_0(500) e^+\nu_e}=1.14\pm0.28, which are compatible with the standard model expectation.Comment: Supplemental Materials added in this versio

    Measurements of the branching fractions of semileptonic Ds+D^{+}_s decays via e+eDs+Dse^+e^-\to D_s^{*+}D_s^{*-}

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    We measure the absolute branching fractions of semileptonic Ds+D^+_s decays via the e+eDs+Dse^+e^-\to D_s^{*+}D_s^{*-} process using e+ee^+e^- collision data corresponding to an integrated luminosity of 10.64 fb110.64~\mathrm{fb}^{-1} collected by the BESIII detector at center-of-mass energies between 4.237 and 4.699 GeV. The branching fractions are B(Ds+ηe+νe)=(2.35±0.11stat±0.10syst)%,{\mathcal B}(D_s^+\to \eta e^+\nu_e)=(2.35\pm0.11_{\rm stat}\pm 0.10_{\rm syst})\%, B(Ds+ηe+νe)=(0.82±0.09stat±0.04syst)%,{\mathcal B}(D_s^+\to \eta^\prime e^+\nu_e)=(0.82\pm0.09_{\rm stat}\pm 0.04_{\rm syst})\%, B(Ds+ϕe+νe)=(2.21±0.16stat±0.11syst)%,{\mathcal B}(D_s^+\to \phi e^+\nu_e)=(2.21\pm0.16_{\rm stat}\pm 0.11_{\rm syst})\%, B(Ds+f0(980)e+νe,f0(980)π+π)=(0.15±0.02stat±0.01syst)%,{\mathcal B}(D_s^+\to f_0(980) e^+\nu_e,f_0(980)\to\pi^+\pi^-)=(0.15\pm0.02_{\rm stat}\pm 0.01_{\rm syst})\%, B(Ds+K0e+νe)=(0.24±0.04stat±0.01syst)%,{\mathcal B}(D_s^+\to K^0 e^+\nu_e)=(0.24\pm0.04_{\rm stat}\pm 0.01_{\rm syst})\%, and B(Ds+K0e+νe)=(0.19±0.03stat±0.01syst)%.{\mathcal B}(D_s^+\to K^{*0} e^+\nu_e)=(0.19\pm0.03_{\rm stat}\pm 0.01_{\rm syst})\%. These results are consistent with those measured via the e+eDs±Dse^+e^-\to D_s^{*\pm}D_s^{\mp} process by BESIII and CLEO. The hadronic transition form factors Ds+ηe+νeD^+_s\to \eta e^+\nu_e, Ds+ηe+νeD^+_s\to \eta^\prime e^+\nu_e, and Ds+K0e+νeD^+_s\to K^0 e^+\nu_e at four-momentum transfer squared q2q^2 = 0 are determined to be f+η(0)=0.482±0.011stat±0.009syst±0.004input,f^{\eta}_+(0) = 0.482 \pm 0.011_{\rm stat} \pm 0.009_{\rm syst}\pm0.004_{\rm input}, f+η(0)=0.562±0.031stat±0.014syst±0.003input,f^{\eta^{\prime}}_+(0) = 0.562 \pm 0.031_{\rm stat} \pm 0.014_{\rm syst}\pm0.003_{\rm input}, and f+K0(0)=0.624±0.052stat±0.013syst±0.002input.f^{K^0}_+(0) = 0.624 \pm 0.052_{\rm stat} \pm 0.013_{\rm syst}\pm0.002_{\rm input}.Comment: 14 pages, 3 figure

    Study of the decays χcJΛΛˉω\chi_{cJ}\to\Lambda\bar{\Lambda}\omega

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    Using (27.12±0.14)×108(27.12\pm 0.14)\times10^{8} ψ(3686)\psi(3686) events collected with the BESIII detector, we present the first observation of the decays χcJΛΛˉω\chi_{cJ}\to\Lambda\bar{\Lambda}\omega, where J=0,1,2J=0, 1, 2, with statistical significances of 11.7σ,11.2σ11.7 \sigma, 11.2 \sigma, and 11.8σ11.8 \sigma. The branching fractions of these decays are determined to be B(χc0ΛΛˉω)=(2.37±0.22±0.23)×104\mathcal{B}(\chi_{c0}\to\Lambda\bar{\Lambda}\omega)=({2.37 \pm 0.22 \pm 0.23}) \times 10^{-4}, B(χc1ΛΛˉω)=(1.01±0.10±0.11)×104\mathcal{B}(\chi_{c1}\to\Lambda\bar{\Lambda}\omega)=({1.01 \pm 0.10 \pm 0.11}) \times 10^{-4}, and B(χc2ΛΛˉω)=(1.40±0.13±0.17)×104\mathcal{B}(\chi_{c2}\to\Lambda\bar{\Lambda}\omega)=({1.40 \pm 0.13 \pm 0.17}) \times 10^{-4}, where the first uncertainties are statistical and the second are systematic. We observe no clear intermediate structures.Comment: 11 pages, 10 figure
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