2,527 research outputs found

    Space-time discontinuous Galerkin method for the compressible Navier-Stokes equations on deforming meshes

    Get PDF
    An overview is given of a space-time discontinuous Galerkin finite element method for the compressible Navier-Stokes equations. This method is well suited for problems with moving (free) boundaries which require the use of deforming elements. In addition, due to the local discretization, the space-time discontinuous Galerkin method is well suited for mesh adaptation and parallel computing. The algorithm is demonstrated with computations of the unsteady \ud ow field about a delta wing and a NACA0012 airfoil in rapid pitch up motion

    Non-continuous Froude number scaling for the closure depth of a cylindrical cavity

    Get PDF
    A long, smooth cylinder is dragged through a water surface to create a cavity with an initially cylindrical shape. This surface void then collapses due to the hydrostatic pressure, leading to a rapid and axisymmetric pinch-off in a single point. Surprisingly, the depth at which this pinch-off takes place does not follow the expected Froude1/3^{1/3} power-law. Instead, it displays two distinct scaling regimes separated by discrete jumps, both in experiment and in numerical simulations (employing a boundary integral code). We quantitatively explain the above behavior as a capillary waves effect. These waves are created when the top of the cylinder passes the water surface. Our work thus gives further evidence for the non-universality of the void collapse

    User Experience Evaluation in BCI: Filling the Gap

    Get PDF
    Brain-computer interface (BCI) systems can improve the user experience (UX) when used in entertainment technologies. Improved UX can enhance user acceptance, improve quality of life and also increase the system performance of a BCI system. Therefore, the evaluation of UX is essential in BCI research. However, BCI systems are generally evaluated according to the system aspect only so there is no methodology to evaluate UX in BCI systems. This paper gives an overview of such methods from the human-computer interaction field and discusses their possible uses in BCI research

    Near-infrared spectroscopy as a diagnostic tool for necrotizing enterocolitis in preterm infants

    Get PDF
    BACKGROUND: We aimed to investigate whether splanchnic tissue oxygen saturation (rsSO2) measured by near-infrared spectroscopy (NIRS) could contribute to the early diagnosis of necrotizing enterocolitis (NEC). METHODS: We retrospectively included infants with suspected NEC, gestational age <32 weeks and/or birth weight <1200 g in the first 3 weeks after birth. We calculated mean rsSO2, cerebral tissue oxygen saturation (rcSO2), variability of rsSO2 (coefficients of variation [rsCoVAR] = SD/mean), and splanchnic-cerebral oxygenation ratio ([SCOR] = rsSO2/rcSO2) in the period around the abdominal radiograph to confirm or reject NEC. RESULTS: Of the 75 infants, 21 (28%) had NEC (Bell's stage ≥2). Characteristics of infants with and without NEC differed only on mechanical ventilation and nil-per-os status. RsSO2 tended to be higher and rcSO2 lower in infants with NEC. RsCoVAR (median [range]) was lower (0.11 [0.03-0.34]) vs. 0.20 [0.01-0.52], P = 0.002) and SCOR higher (0.64 [0.37-1.36]) vs. 0.47 [0.16-1.09], P = 0.004) in NEC infants. Adjusted for postnatal age, mechanical ventilation, and nil-per-os status, a 0.1 higher rsCoVAR decreased the likelihood of NEC diagnosis with likelihood ratio (LR) 0.38 (95% CI 0.18-0.78) and a 0.1 higher SCOR increased it with LR 1.28 (1.02-1.61). CONCLUSIONS: Using NIRS, high SCOR may confirm NEC and high variability of rsSO2 may rule out NEC, when suspicion arises. IMPACT: Near-infrared spectroscopy may contribute to the diagnosis of necrotizing enterocolitis.When clinical signs are present a high splanchnic-cerebral oxygenation may indicate necrotizing enterocolitis.A low splanchnic-cerebral oxygenation ratio and high variability of splanchnic tissue oxygen saturation may rule out necrotizing enterocolitis.Whether a bedside real-time availability of the splanchnic-cerebral oxygenation ratio and variability of splanchnic tissue oxygen saturation improves NEC diagnosis needs to be further investigated

    Synthesis and biological evaluation of immunoconjugates of adriamycin and a human IgM linked by poly[N5-(2-hydroxyethyl)-l-glutamine

    Get PDF
    The synthesis and purification of radiolabelled immunoconjugates, composed of a human IgM monoclonal antibody (IgM 16.88) directed against an intracellular tumour-associated antigen, the drug carrier poly[N5-(2-hydroxyethyl)--glutamine] (PHEG) and the cytostatic drug adriamycin (ADR) are described. The immunoconjugates were constructed to allow selective release of ADR in the putatively acidic environment of the tumour through a novel acid-labile maleamic acid linker. The conjugate of PHEG and the acid-labile ADR derivative effectively released ADR in cytotoxic amounts at a pH of 6.0 as judged from incubation in buffer and from inhibition of the growth of HT-29 colon tumour cells in vitro. Immunoconjugates were prepared by coupling of PHEG-ADR having a hydrolytically stable amide bond with 131I-labelled antibody through thioether bond formation involving a single thiol group at the C-terminus of the polymer chain and maleimido groups introduced onto th

    Use of SSRIs during pregnancy and possible consequences for the development of the child

    Get PDF
    Infants of depressed mothers are at increased risk for developing cognitive and behavioural problems. Medication is often prescribed for pregnant women suffering from a major depression. Approximately 2% of Dutch pregnant women is using a selective serotonin reuptake inhibitor (SSRI). SSRIs cross the placenta easily. The consequences of prenatal exposure to SSRIs for the developing child remain to be determined. In the postnatal period, increased incidence of respiratory distress, feeding and digestive disturbances, irritability and convulsions, and admission to a neonatal intensive care unit have been described. Long-term effects have not yet been thoroughly examined in humans. Animal studies have shown permanent changes in specific parts of the brain and altered behaviour in adulthood after perinatal exposure to SSRIs. Research into motor and cognitive development at school age and adolescence in children prenatally exposed to SSRIs is urgently needed.</p

    Use of SSRIs during pregnancy and possible consequences for the development of the child

    Get PDF
    Infants of depressed mothers are at increased risk for developing cognitive and behavioural problems. Medication is often prescribed for pregnant women suffering from a major depression. Approximately 2% of Dutch pregnant women is using a selective serotonin reuptake inhibitor (SSRI). SSRIs cross the placenta easily. The consequences of prenatal exposure to SSRIs for the developing child remain to be determined. In the postnatal period, increased incidence of respiratory distress, feeding and digestive disturbances, irritability and convulsions, and admission to a neonatal intensive care unit have been described. Long-term effects have not yet been thoroughly examined in humans. Animal studies have shown permanent changes in specific parts of the brain and altered behaviour in adulthood after perinatal exposure to SSRIs. Research into motor and cognitive development at school age and adolescence in children prenatally exposed to SSRIs is urgently needed.</p

    Use of SSRIs during pregnancy and possible consequences for the development of the child

    Get PDF
    Infants of depressed mothers are at increased risk for developing cognitive and behavioural problems. Medication is often prescribed for pregnant women suffering from a major depression. Approximately 2% of Dutch pregnant women is using a selective serotonin reuptake inhibitor (SSRI). SSRIs cross the placenta easily. The consequences of prenatal exposure to SSRIs for the developing child remain to be determined. In the postnatal period, increased incidence of respiratory distress, feeding and digestive disturbances, irritability and convulsions, and admission to a neonatal intensive care unit have been described. Long-term effects have not yet been thoroughly examined in humans. Animal studies have shown permanent changes in specific parts of the brain and altered behaviour in adulthood after perinatal exposure to SSRIs. Research into motor and cognitive development at school age and adolescence in children prenatally exposed to SSRIs is urgently needed.</p

    Exploring the emotional dynamics of subclinically depressed individuals with and without anhedonia:An experience sampling study

    Get PDF
    Background: Anhedonia has been linked to worse prognosis of depression. The present study aimed to construct personalized models to elucidate the emotional dynamics of subclinically depressed individuals with versus without symptoms of anhedonia. Methods: Matched subclinically depressed individuals with and without symptoms of anhedonia (N = 40) of the HowNutsAreTheDutch sample completed three experience sampling methodology assessments per day for 30 days. For each individual, the impact of physical activity, stress experience, and high/low arousal PA/NA on each other was estimated through automated impulse response function analysis (IRF). These individual IRF associations were combined to compare anhedonic versus non-anhedonic individuals. Results: Physical activity had low impact on affect in both groups. In non-anhedonic individuals, stress experience increased NA and decreased PA and physical activity more strongly. In anhedonic individuals, PA high arousal showed a diminished favorable impact on affect (increasing NA/stress experience, decreasing PA/physical activity). Finally, large heterogeneity in the personalized models of emotional dynamics were found. Limitations: Stress experience was measured indirectly by assessing level of distress; the timeframe in between measurements was relatively long with 6 h; and only information on one of the two hallmarks of anhedonia, loss of interest, was gathered. Conclusions: Our results suggest different pathways of emotional dynamics underlie depressive symptomatology. Subclinically depressed individuals with anhedonic complaints are more strongly characterized by diminished favorable impact of PA high arousal and heightened NA reactivity, whereas subclinically depressed individuals without these anhedonic complaints seem more characterized by heightened stress reactivity. The automatically generated personalized models may offer patient-specific insights in emotional dynamics, which may show clinical relevance
    • …
    corecore