817 research outputs found

    Resonance lamp absorption measurement of OH number density and temperature in expansion tube scramjet engine tests

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    In this paper, we report results of hydroxyl radical and static temperature measurements performed in the General Applied Science Laboratories-NASA HYPULSE expansion tube facility using the microwave resonance lamp absorption technique. Data were obtained as part of a series of hydrogen/air and hydrogen/oxygen combustion tests at stagnation enthalpies corresponding to Mach 17 flight speeds. Data from a representative injector configuration is compared to a full Navier-Stokes CFD solution

    Visualization of hydrogen injection in a scramjet engine by simultaneous PLIF imaging and laser holographic imaging

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    Flowfield characterization has been accomplished for several fuel injector configurations using simultaneous planar laser induced fluorescence (PLIF) and laser holographic imaging (LHI). The experiments were carried out in the GASL-NASA HYPULSE real gas expansion tube facility, a pulsed facility with steady test times of about 350 microsec. The tests were done at simulated Mach numbers 13.5 and 17. The focus of this paper is on the measurement technologies used and their application in a research facility. The HYPULSE facility, the models used for the experiments, and the setup for the LHI and PLIF measurements are described. Measurement challenges and solutions are discussed. Results are presented for experiments with several fuel injector configurations and several equivalence ratios

    Multistationary and Oscillatory Modes of Free Radicals Generation by the Mitochondrial Respiratory Chain Revealed by a Bifurcation Analysis

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    The mitochondrial electron transport chain transforms energy satisfying cellular demand and generates reactive oxygen species (ROS) that act as metabolic signals or destructive factors. Therefore, knowledge of the possible modes and bifurcations of electron transport that affect ROS signaling provides insight into the interrelationship of mitochondrial respiration with cellular metabolism. Here, a bifurcation analysis of a sequence of the electron transport chain models of increasing complexity was used to analyze the contribution of individual components to the modes of respiratory chain behavior. Our algorithm constructed models as large systems of ordinary differential equations describing the time evolution of the distribution of redox states of the respiratory complexes. The most complete model of the respiratory chain and linked metabolic reactions predicted that condensed mitochondria produce more ROS at low succinate concentration and less ROS at high succinate levels than swelled mitochondria. This prediction was validated by measuring ROS production under various swelling conditions. A numerical bifurcation analysis revealed qualitatively different types of multistationary behavior and sustained oscillations in the parameter space near a region that was previously found to describe the behavior of isolated mitochondria. The oscillations in transmembrane potential and ROS generation, observed in living cells were reproduced in the model that includes interaction of respiratory complexes with the reactions of TCA cycle. Whereas multistationarity is an internal characteristic of the respiratory chain, the functional link of respiration with central metabolism creates oscillations, which can be understood as a means of auto-regulation of cell metabolism. © 2012 Selivanov et al

    Contributions of Caregiver Management Styles to the Discrepancy Between Reported and Observed Task Performance in People with Dementia

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    Background: The identification and understanding of the discrepancy between caregivers’ reports of people with dementia’s (PwD) performance of activities of daily living (ADLs) and observed performance, could clarify what kind of support a PwD effectively needs when completing tasks. Strategies used by caregivers have not been included in the investigation of this discrepancy. Objectives: To (1) investigate if caregivers’ report of PwD’s ADL performance are consistent with PwD’s observed performance; (2) explore if caregiver management styles, depression, and anxiety, contribute to this discrepancy. Methods: PwD (n=64) were assessed with standardised performance-based (AMPS) and informant-based (DAD) ADL assessments. Caregivers completed depression (PHQ-9), anxiety (GAD-7), and dementia management style (DMSS: criticism, active-management, and encouragement) questionnaires. Cohen’s kappa determined agreement/disagreement in ADL performance. To investigate the potential discrepancy between the DAD and AMPS, a continuous variable was generated: comparative ADL score. Multiple linear regression analysis explored whether caregivers’ management styles, depression or anxiety could explain the ADL discrepancy. Results: Poor level of agreement between observed and reported ADL performance [k= -0.025 (95%CI -0.123 – 0.073)] was identified, with most caregivers underestimating ADL performance. The combined model explained 18% (R2=0.18, F(5, 55)=2.52,p=<0.05) of the variance of the comparative ADL score. Active-management (β=-0.037,t(60)=-3.363, p=0.001) and encouragement (β=0.025,t(60)=2.018, p=0.05) styles made the largest and statistically significant contribution to the model. Conclusions: Encouragement style could be advised for caregivers who underestimate ADL performance, while active management style for those who overestimate it. Findings have scope to increase caregivers’ abilities to support PwD activity engagement in daily life

    A New and Tidier Setting How Does Environmental Clutter Affect People With Dementia’s Ability to Perform Activities of Daily Living?

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    Background: The relationship between the physical environment and the person with dementia’s (PwD) activities of daily living (ADLs) task performance is controversial. Although the general assumption is that this population benefits from their home environment when performing ADLs, very few experimental studies have been conducted to date. Objectives: The aim was to investigate the influence of the environment (home vs. Research-lab) and the role of clutter on ADL performance. Methods: Sixty-five PwD were evaluated with a performance-based ADL assessment (at home and clutter-free Research-lab). Paired t tests compared ADL performance and level of clutter in both environments. Multiple regression analysis investigated factors associated with better ADL performance. Results: Overall, PwD performed better at home even though clutter was significantly lower in the Research-lab. When stratified by dementia stage, PwD in the moderate stage of the disease performed better at home. Conclusion: Absence of clutter in the Research-Lab did not appear to play a beneficial role in ADLs. When stratified by dementia stage, only PwD in the moderate stage appeared to benefit from their home environment when performing ADL tasks. Future studies are required to elucidate the wider role of the environment in supporting engagement in daily activities in different dementia stages

    Analysis of particle size distribution in municipal wastewaters

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    Innovative membrane filtration plants for municipal wastewaters are being developed and need the support of reliable filtration models in the designing phase. In the past, semi-empirical filtration models for membrane processes have been proposed. At present, the most prominent works point out the importance of particle poly-dispersity in the development of reliable models but fail into the implementation of probability density functions (PDFs) capable of an accurate fitting of the experimental particle size distribution (PSD). We report the experimental PSDs of two different municipal wastewater samples, obtained through the laser diffraction technique. The experimental results show that the laser diffraction technique can characterize wastewater particle dimensions both in the colloidal and supra-colloidal regions. The experimental study is complemented by a comparative analysis in which many PDFs are used to fit the experimental PSDs through a least-squares approach. Some of these PDFs are proposed here for the first time to fit experimental wastewater PSDs. Among the PDFs considered for the statistical modeling, the three-parameter lognormal and the Burr PDFs are demonstrated to provide satisfactory fitting, whereas the other considered functions fail. This result is confirmed by the analysis of both the available wastewater samples

    External validation of ADO, DOSE, COTE and CODEX at predicting death in primary care patients with COPD using standard and machine learning approaches

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    Background Several models for predicting the risk of death in people with chronic obstructive pulmonary disease (COPD) exist but have not undergone large scale validation in primary care. The objective of this study was to externally validate these models using statistical and machine learning approaches. Methods We used a primary care COPD cohort identified using data from the UK Clinical Practice Research Datalink. Age-standardised mortality rates were calculated for the population by gender and discrimination of ADO (age, dyspnoea, airflow obstruction), COTE (COPD-specific comorbidity test), DOSE (dyspnoea, airflow obstruction, smoking, exacerbations) and CODEX (comorbidity, dyspnoea, airflow obstruction, exacerbations) at predicting death over 1–3 years measured using logistic regression and a support vector machine learning (SVM) method of analysis. Results The age-standardised mortality rate was 32.8 (95%CI 32.5–33.1) and 25.2 (95%CI 25.4–25.7) per 1000 person years for men and women respectively. Complete data were available for 54879 patients to predict 1-year mortality. ADO performed the best (c-statistic of 0.730) compared with DOSE (c-statistic 0.645), COTE (c-statistic 0.655) and CODEX (c-statistic 0.649) at predicting 1-year mortality. Discrimination of ADO and DOSE improved at predicting 1-year mortality when combined with COTE comorbidities (c-statistic 0.780 ADO + COTE; c-statistic 0.727 DOSE + COTE). Discrimination did not change significantly over 1–3 years. Comparable results were observed using SVM. Conclusion In primary care, ADO appears superior at predicting death in COPD. Performance of ADO and DOSE improved when combined with COTE comorbidities suggesting better models may be generated with additional data facilitated using novel approaches

    The enzymatic transformation of galactose into glucose derivatives

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    originalFil: Caputto, Ranwel. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Leloir, Luis Federico. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Trucco, Raúl E.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Cardini, Carlos E.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Paladini, Alejandro C.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaBlanco y negro2 páginas en pdfLFL-PI-O-ART. Artículos científicosUnidad documental simpleAR-HYL-201

    A coenzyme for phosphoglucomutase

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    originalFil: Caputto, Ranwel. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Leloir, Luis Federico. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Trucco, Raúl E.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Cardini, Carlos E.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Paladini, Alejandro C.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaBlanco y negro2 páginas en pdfLFL-PI-O-ART. Artículos científicosUnidad documental simpleAR-HYL-201

    The isolation of the coenzyme of phosphoglucomutase

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    originalFil: Cardini, Carlos E.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Paladini, Alejandro C.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Caputto, Ranwel. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Leloir, Luis Federico. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaFil: Trucco, Raúl E.. Instituto de Investigaciones Bioquímicas Fundación Campomar; ArgentinaBlanco y negro8 páginas en pdfLFL-PI-O-ART. Artículos científicosUnidad documental simpleAR-HYL-201
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