4,340 research outputs found

    Unravelling complex systems

    Get PDF

    Sarcoidosis Presenting as Acute Respiratory Distress Syndrome.

    Get PDF
    Sarcoidosis is a multisystem granulomatous disease of unknown origin. It typically involves the lungs and mediastinal lymph nodes in a chronic fashion. However, acute syndrome has been reported possibly in response to systemic release of proinflammatory cytokines. Acute pulmonary manifestations, especially acute respiratory failure or acute respiratory distress syndrome, remain extremely uncommon in individuals without a prior diagnosis. We present the case of a 41-year-old African American female, who presented with ARDS. An extensive workup into the cause of her illness remained negative, and she subsequently succumbed to her illness. A diagnosis of sarcoidosis was made upon autopsy, after exclusion of other granulomatous illness. The case highlights the need to consider this uncommon diagnosis in patients with unexplained ARDS to guide therapy

    Superior Facial Expression, But Not Identity Recognition, in Mirror-Touch Synesthesia

    Get PDF
    Simulation models of expression recognition contend that to understand another's facial expressions, individuals map the perceived expression onto the same sensorimotor representations that are active during the experience of the perceived emotion. To investigate this view, the present study examines facial expression and identity recognition abilities in a rare group of participants who show facilitated sensorimotor simulation (mirror-touch synesthetes). Mirror-touch synesthetes experience touch on their own body when observing touch to another person. These experiences have been linked to heightened sensorimotor simulation in the shared-touch network (brain regions active during the passive observation and experience of touch). Mirror-touch synesthetes outperformed nonsynesthetic participants on measures of facial expression recognition, but not on control measures of face memory or facial identity perception. These findings imply a role for sensorimotor simulation processes in the recognition of facial affect, but not facial identity

    Suppressing sensorimotor activity modulates the discrimination of auditory emotions but not speaker identity

    Get PDF
    Our ability to recognize the emotions of others is a crucial feature of human social cognition. Functional neuroimaging studies indicate that activity in sensorimotor cortices is evoked during the perception of emotion. In the visual domain, right somatosensory cortex activity has been shown to be critical for facial emotion recognition. However, the importance of sensorimotor representations in modalities outside of vision remains unknown. Here we use continuous theta-burst transcranial magnetic stimulation (cTBS) to investigate whether neural activity in the right postcentral gyrus (rPoG) and right lateral premotor cortex (rPM) is involved in nonverbal auditory emotion recognition. Three groups of participants completed same-different tasks on auditory stimuli, discriminating between the emotion expressed and the speakers' identities, before and following cTBS targeted at rPoG, rPM, or the vertex (control site). A task-selective deficit in auditory emotion discrimination was observed. Stimulation to rPoG and rPM resulted in a disruption of participants' abilities to discriminate emotion, but not identity, from vocal signals. These findings suggest that sensorimotor activity may be a modality-independent mechanism which aids emotion discrimination. Copyright © 2010 the authors

    Un système d'information géoscientifique pour la ville de Sherbrooke, Québec

    Get PDF
    Urban planners as well as civil engineers of the town of Sherbrooke, still do not yet have a geoscientific information databank (GSID) that can show, with the help of a geographic information system (GIS), unconsolidated deposits and their three-dimensional aspect (thickness, topography and stratigraphy). Therefore, the main goal of this research project consists in making a detailed geoscientific information system (GSIS) of the Sherbrooke region, covering an area of 150 km 2 approximately. The GSID is elaborated essentially from well and borehole data, geotechnical reports, cartographic data and field observations. The elaboration of the GSIS is first done by setting up a GSID on Excel , using point data from the region. This GSID is then verified and corrected before being integrated finally in the ArcView GIS. In the case of boreholes not reaching the bedrock, further corrections to the thickness of the overburden are effected with the help of data from nearby boreholes and a series of successive interpolations. With ArcView software, interpolation maps can be drawn up. Several types of maps are derived from the GSID: bedrock topography, depth of the upper limit of the water table, total thickness to the overburden, and thickness and topography of different unconsolidated formations. The interpolation method used is Kriging when possible. The computation is based on a theoretical model chosen by the analysis of semi-variogrammes. By integrating the GSID to a GIS, the various municipal authorities can use the GSIS to keep an inventory of the stratigraphy of Sherbrooke's territory and define, among other things, risk zones in accordance with constraints of town planning and building of infrastructures

    Anion–π Enzymes

    Get PDF
    In this report, we introduce artificial enzymes that operate with anion-π interactions, an interaction that is essentially new to nature. The possibility to stabilize anionic intermediates and transition states on an π-acidic surface has been recently demonstrated, using the addition of malonate half thioesters to enolate acceptors as a biologically relevant example. The best chiral anion-π catalysts operate with an addition/decarboxylation ratio of 4:1, but without any stereoselectivity. To catalyze this important but intrinsically disfavored reaction stereoselectively, a series of anion-π catalysts was equipped with biotin and screened against a collection of streptavidin mutants. With the best hit, the S112Y mutant, the reaction occurred with 95% ee and complete suppression of the intrinsically favored side product from decarboxylation. This performance of anion-π enzymes rivals, if not exceeds, that of the best conventional organocatalysts. Inhibition of the S112Y mutant by nitrate but not by bulky anions supports that contributions from anion-π interactions exist and matter, also within proteins. In agreement with docking results, K121 is shown to be essential, presumably to lower the p K a of the tertiary amine catalyst to operate at the optimum pH around 3, that is below the p K a of the substrate. Most importantly, increasing enantioselectivity with different mutants always coincides with increasing rates and conversion, i.e., selective transition-state stabilization

    Frequency converter implementing an optical analogue of the cosmological redshift

    Full text link
    According to general relativity, the frequency of electromagnetic radiation is altered by the expansion of the universe. This effect--commonly referred to as the cosmological redshift--is of utmost importance for observations in cosmology. Here we show that this redshift can be reproduced on a much smaller scale using an optical analogue inside a dielectric metamaterial with time-dependent material parameters. To this aim, we apply the framework of transformation optics to the Robertson-Walker metric. We demonstrate theoretically how perfect redshifting or blueshifting of an electromagnetic wave can be achieved without the creation of sidebands with a device of finite length.Comment: 6 pages, 3 figure

    Metabolite-dependent regulation of gene expression in trypanosoma brucei

    Get PDF
    Mechanisms regulating gene expression in trypanosomatid protozoa differ significantly from those in other eukaryotes. Transcription of the genome appears to be more or less constitutive with the polyadenylation and trans-splicing of large polycistronic RNAs producing monocistronic RNAs whose translation may then depend upon information within their 3′ untranslated regions (3′UTRs). Various 3′UTR sequences involved in life-cycle stage-dependent differential gene expression have been described. Moreover, several RNA-binding proteins have been implicated in regulating expression of these transcripts through altering either their stability or their ability to interact with ribosomes. In this issue of Molecular Microbiology Xiao et al. report on a regulatory element within the 3′UTR of the transcript that encodes the polyamine pathway regulatory protein called prozyme. It appears that the RNA element controls translation of the prozyme RNA causing expression to be upregulated when levels of decarboxylated S-adenosylmethionine (dcAdoMet) are depleted. Since prozyme activates the enzyme S-adenosylmethionine decarboxylase (AdoMetDC), which is responsible for the production of dcAdoMet, losing this metabolite leads to upregulation of prozyme, activation of AdoMetDC and restoration of optimal levels of dcAdomet. The system thus represents a novel metabolite-sensing regulatory circuit that maintains polyamine homeostasis in these cells

    Efficacy of Three-Week Oxytetracycline or Rifampin Monotherapy Compared with a Combination Regimen against the Filarial Nematode Onchocerca ochengi

    Get PDF
    Onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, is a major cause of visual impairment and dermatitis in sub-Saharan Africa. As O. volvulus contains an obligatory bacterial symbiont (Wolbachia), it is susceptible to antibiotic chemotherapy, although current regimens are considered too prolonged for community-level control programs. The aim of this study was to compare the efficacies of oxytetracycline and rifampin, administered separately or in combination, against a close relative of O. volvulus (Onchocerca ochengi) in cattle. Six animals per group were treated with continuous or intermittent oxytetracycline regimens, and effects on adult worm viability, dermal microfilarial loads, and Wolbachia density in worm tissues were assessed. Subsequently, the efficacies of 3-week regimens of oxytetracycline and rifampin alone and a combination regimen were compared, and rifampin levels in plasma and skin were quantified. A 6-month regimen of oxytetracycline with monthly dosing was strongly adulticidal, while 3-week and 6-week regimens exhibited weaker adulticidal effects. However, all three regimens achieved >2-log reductions in microfilarial load. In contrast, rifampin monotherapy and oxytetracycline-rifampin duotherapy failed to induce substantive reductions in either adult worm burden or microfilarial load, although a borderline effect on Wolbachia density was observed following duotherapy. Dermal rifampin levels were maintained above the MIC for >24 h after a single intravenous dose. We conclude that oxytetracycline-rifampin duotherapy is less efficacious against O. ochengi than oxytetracycline alone. Further studies will be required to determine whether rifampin reduces oxytetracycline bioavailability in this system, as suggested by human studies using other tetracycline-rifampin combinations
    • …
    corecore