59 research outputs found

    Gender and age differences in polysomnography findings and sleep complaints of patients referred to a sleep laboratory

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    Our objective was to examine the effet of gender on the sleep pattern of patients referred to a sleep laboratory. The data (questionnaires and polysomnographic recordings) were collected from a total of 2365 patients (1550 men and 815 women). The polysomnography permits an objective assessment of the sleep pattern. We included only polysomnography exams obtained with no more than one recording system in order to permit normalization of the data. Men had a significantly higher body mass index than women (28.5 ± 4.8 vs 27.7 ± 6.35 kg/m²) and had a significantly higher score on the Epworth Sleepiness Scale (10.8 ± 5.3 vs 9.5 ± 6.0), suggesting daytime sleepiness. Women had a significantly higher sleep latency than men, as well as a higher rapid eye movement (REM) latency. Men spent more time in stages 1 (4.6 ± 4.1 vs 3.9 ± 3.8) and 2 (57.0 ± 10.5 vs 55.2 ± 10.1) of non-REM sleep than women, whereas women spent significantly more time in deep sleep stages (3 and 4) than men (22.6 ± 9.0 vs 19.9 ± 9.0). The apnea/hypopnea and arousal indexes were significantly higher and more frequent in men than in women (31.0 ± 31.5 vs 17.3 ± 19.7). Also, periodic leg movement index did not differ significantly between genders, but rather differed among age groups. We did not find significant differences between genders in the percentage of REM sleep and sleep efficiency. The results of the current study suggest that there are specific gender differences in sleep pattern.1067107

    Fractional-orderuniaxial visco-elasto-plastic models for structural analysis

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    Three fractional-order models for uniaxial large strains and rate-dependent plastic behavior of materials instructural analysis are proposed. Our approach is a menable to modeling nonlinear and more sophisticated effects namely visco-elasto-plastic response of materials. This approach seamlessly interpolates between the standard elasto-plastic and visco-plastic models in plasticity, taking in to account the history-dependency of the accumulated plastic strain to specify the state of stress. To this end, we propose three models namely i) viscoelasto-plastic with linear hardening plastic model, ii )elasto-viscoplastic model, and iii) visco-elasto-plastic model, which combines the first the second models. We employ afractional-order constitutive law that relates the Kirchhoff stress to its Caputo time-fractional derivative of order α ∈ (0,1]. When α → 0 the standard elasto-plastic (rate-independent) model and when α = 1, the corresponding visco-plastic model is recovered. Since the material behavior is path-dependent the evolution of the plastic strainis achieved by fractional-order time integration of the plastic strain rate with respect to time. The strain rate is then obtained by means of the corresponding plastic multiplier and deriving proper consistency conditions. Finally, we develop a so called fractional return-mapping algorithm for solving the nonlinear system of the equilibrium equations developing in each model

    Outcome of children with multiply relapsed B-cell acute lymphoblastic leukemia: a therapeutic advances in childhood leukemia & lymphoma study.

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    The survival of pediatric patients with multiply relapsed and/or refractory (R/R) B-cell acute lymphoblastic leukemia has historically been very poor; however, data are limited in the current era. We conducted a retrospective study to determine the outcome of multiply R/R childhood B-ALL treated at 24 TACL institutions between 2005 and 2013. Patient information, treatment, and response were collected. Prognostic factors influencing the complete remission (CR) rate and event-free survival (EFS) were analyzed. The analytic set included 578 salvage treatment attempts among 325 patients. CR rates (mean ± SE) were 51 ± 4% for patients with bone marrow R/R B-ALL who underwent a second salvage attempt, 37 ± 6% for a third attempt, and 31 ± 6% for the fourth through eighth attempts combined. For patients achieving a CR after their second, third, and fourth through eighth attempts, the 2 year EFS was 41 ± 6%, 13 ± 7%, and 27 ± 13% respectively. Our results showed slight improvement when compared to previous studies. This is the largest and most recent study to date that evaluates the outcome of this patient population. Our data will provide detailed reference for the evaluation of new agents being developed for childhood B-ALL

    A fourth-order degradation tensor for an anisotropic damage phase-field model

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    This work proposes a thermodynamically consistent phase-field model for anisotropic brittle material under the hypotheses of plane stress, small deformation and constant temperature. The model is derived from the principle of virtual power, the first and second laws of thermodynamics in the form of the Clausius-Duhem inequality. The degradation effect on the material behavior is given by a fourth-order degradation tensor introduced as an internal variable that evolves according to the current strain state rather than the conventional scalar degradation function of phase-field models. Therefore, local anisotropy can be induced, changing the material mechanical behavior differently in all directions organically. The proposed degradation tensor is defined in the global coordinate system and therefore is sensitive to any change in the principal directions of the strain and stress states. To demonstrate the model’s capability of representing damage in isotropic and transversely isotropic materials, some benchmark examples were carried out and the evolution of the damage components was analyzed

    Fractional-orderuniaxial visco-elasto-plastic models for structural analysis

    No full text
    Three fractional-order models for uniaxial large strains and rate-dependent plastic behavior of materials instructural analysis are proposed. Our approach is a menable to modeling nonlinear and more sophisticated effects namely visco-elasto-plastic response of materials. This approach seamlessly interpolates between the standard elasto-plastic and visco-plastic models in plasticity, taking in to account the history-dependency of the accumulated plastic strain to specify the state of stress. To this end, we propose three models namely i) viscoelasto-plastic with linear hardening plastic model, ii )elasto-viscoplastic model, and iii) visco-elasto-plastic model, which combines the first the second models. We employ afractional-order constitutive law that relates the Kirchhoff stress to its Caputo time-fractional derivative of order α ∈ (0,1]. When α → 0 the standard elasto-plastic (rate-independent) model and when α = 1, the corresponding visco-plastic model is recovered. Since the material behavior is path-dependent the evolution of the plastic strainis achieved by fractional-order time integration of the plastic strain rate with respect to time. The strain rate is then obtained by means of the corresponding plastic multiplier and deriving proper consistency conditions. Finally, we develop a so called fractional return-mapping algorithm for solving the nonlinear system of the equilibrium equations developing in each model
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