87 research outputs found

    Modelling of high pressure binary droplet collisions

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    AbstractDroplet collision efficiency is a rather uncharted area for real hydrocarbon systems under non-atmospheric conditions. It is also of great interest in many industrial applications. In this work binary head-on droplet collisions at high pressure have been simulated using the lattice Boltzmann method. A model that captures the physics of the coalescence process is used where no external criterion for coalescence is needed. The collision process is described in terms of hydrodynamic variables and through a quantitative study of energy loss. At high pressures, low inertia collisions are the most frequent. Distinguishing between bouncing and coalescence under these conditions is needed in order to provide closure conditions for macroscopic CFD models. A limit of Re<170ρlg is found to predict coalescence in all the cases simulated. In addition this paper explains the stochastic behaviour of low inertia coalescence at high pressure. This has major implications both when building macroscopic models for predicting industrial process efficiencies and in the optimization of equipment internals working with droplets at high pressure as is the case for combustion chambers and gas–liquid separators

    Cortisol-Induced Masculinization: Does Thermal Stress Affect Gonadal Fate in Pejerrey, a Teleost Fish with Temperature-Dependent Sex Determination?

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    BACKGROUND: Gonadal fate in many reptiles, fish, and amphibians is modulated by the temperature experienced during a critical period early in life (temperature-dependent sex determination; TSD). Several molecular processes involved in TSD have been described but how the animals "sense" environmental temperature remains unknown. We examined whether the stress-related hormone cortisol mediates between temperature and sex differentiation of pejerrey, a gonochoristic teleost fish with marked TSD, and the possibility that it involves glucocorticoid receptor- and/or steroid biosynthesis-modulation. METHODOLOGY/PRINCIPAL FINDINGS: Larvae maintained during the period of gonadal sex differentiation at a masculinizing temperature (29 degrees C; 100% males) consistently had higher cortisol, 11-ketotestoterone (11-KT), and testosterone (T) titres than those at a feminizing temperature (17 degrees C; 100% females). Cortisol-treated animals had elevated 11-KT and T, and showed a typical molecular signature of masculinization including amh upregulation, cyp19a1a downregulation, and higher incidence of gonadal apoptosis during sex differentiation. Administration of cortisol and a non-metabolizable glucocorticoid receptor (GR) agonist (Dexamethasone) to larvae at a "sexually neutral" temperature (24 degrees C) caused significant increases in the proportion of males. CONCLUSIONS/SIGNIFICANCE: Our results suggest a role of cortisol in the masculinization of pejerrey and provide a possible link between stress and testicular differentiation in this gonochoristic TSD species. Cortisol role or roles during TSD of pejerrey seem(s) to involve both androgen biosynthesis- and GR-mediated processes. These findings and recent reports of cortisol effects on sex determination of sequential hermaphroditic fishes, TSD reptiles, and birds provide support to the notion that stress responses might be involved in various forms of environmental sex determination

    Cortical dynamics and subcortical signatures of motor-language coupling in Parkinson’s disease

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    ABSTRACT: Impairments of action language have been documented in early stage Parkinson’s disease (EPD). The action-sentence compatibility effect (ACE) paradigm has revealed that EPD involves deficits to integrate action-verb processing and ongoing motor actions. Recent studies suggest that an abolished ACE in EPD reflects a cortico-subcortical disruption, and recent neurocognitive models highlight the role of the basal ganglia (BG) in motor-language coupling. Building on such breakthroughs, we report the first exploration of convergent cortical and subcortical signatures of ACE in EPD patients and matched controls. Specifically, we combined cortical recordings of the motor potential, functional connectivity measures, and structural analysis of the BG through voxelbased morphometry. Relative to controls, EPD patients exhibited an impaired ACE, a reduced motor potential, and aberrant frontotemporal connectivity. Furthermore, motor potential abnormalities during the ACE task were predicted by overall BG volume and atrophy. These results corroborate that motor-language coupling is mainly subserved by a cortico-subcortical network including the BG as a key hub. They also evince that action-verb processing may constitute a neurocognitive marker of EPD. Our findings suggest that research on the relationship between language and motor domains is crucial to develop models of motor cognition as well as diagnostic and intervention strategies

    Effects of endocrine disrupting chemicals on gonad development: Mechanistic insights from fish and mammals

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    Over the past century, evidence has emerged that endocrine disrupting chemicals (EDCs) have an impact on reproductive health. An increased frequency of reproductive disorders has been observed worldwide in both wildlife and humans that is correlated with accidental exposures to EDCs and their increased production. Epidemiological and experimental studies have highlighted the consequences of early exposures and the existence of key windows of sensitivity during development. Such early in life exposures can have an immediate impact on gonadal and reproductive tract development, as well as on long-term reproductive health in both males and females. Traditionally, EDCs were thought to exert their effects by modifying the endocrine pathways controlling reproduction. Advances in knowledge of the mechanisms regulating sex determination, differentiation and gonadal development in fish and rodents have led to a better understanding of the molecular mechanisms underlying the effects of early exposure to EDCs on reproduction. In this manuscript, we review the key developmental stages sensitive to EDCs and the state of knowledge on the mechanisms by which model EDCs affect these processes, based on the roadmap of gonad development specific to fish and mammals.The authors are grateful to the Intersectoral Centre for Endocrine Disruptor Analysis (ICEDA)'s researcher network that facilitated this Special Issue. LNM was supported by a H2020-Marie Skłodowska-Curie Action MSCA-IF-RI- 2017 awarded by the European Commission (ref. 797725-EpiSTOX).With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

    Decoding Brain Activity Associated with Literal and Metaphoric Sentence Comprehension Using Distributional Semantic Models

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    Recent years have seen a growing interest within the natural language processing (NLP)community in evaluating the ability of semantic models to capture human meaning representation in the brain. Existing research has mainly focused on applying semantic models to de-code brain activity patterns associated with the meaning of individual words, and, more recently, this approach has been extended to sentences and larger text fragments. Our work is the first to investigate metaphor process-ing in the brain in this context. We evaluate a range of semantic models (word embeddings, compositional, and visual models) in their ability to decode brain activity associated with reading of both literal and metaphoric sentences. Our results suggest that compositional models and word embeddings are able to capture differences in the processing of literal and metaphoric sentences, providing sup-port for the idea that the literal meaning is not fully accessible during familiar metaphor comprehension

    Interim 2017/18 influenza seasonal vaccine effectiveness: Combined results from five European studies

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    Between September 2017 and February 2018, influenza A(H1N1)pdm09, A(H3N2) and B viruses (mainly B/Yamagata, not included in 2017/18 trivalent vaccines) co-circulated in Europe. Interim results from five European studies indicate that, in all age groups, 2017/18 influenza vaccine effectiveness was 25 to 52% against any influenza, 55 to 68% against influenza A(H1N1)pdm09, -42 to 7% against influenza A(H3N2) and 36 to 54% against influenza B. 2017/18 influenza vaccine should be promoted where influenza still circulates
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