424 research outputs found
Strain-inducing mechanism of a rolling nip on a paper stack
The rolling of a cylindrical drum on a stack of separate paper sheets is studied using the finite element method. A two dimensional model under plane strain conditions is considered. The material of the sheets is modeled by a linearly elastic orthotropic constitutive law. The friction between the various contacting surfaces is modeled by the conventional Coulomb's law. As a result of the FEM-calculations the time development of the displacements, stresses and strains of the paper layers is obtained. The slip behavior at the various contacting surfaces is presented. The results indicate the existence of an instant center in the stack demonstrated earlier experimentally. The micro-slip pattern of the contacting surfaces in the nip area and, particularly, at the trailing edge of the nip, seems to be the main reason for the tightening effect of the nip. The results are compared to the corresponding results for a solid elastic block under the rolling cylinder
Study of stress-strain relation for paper roll
In the present method a wound roll of paper is loaded against a nip roller and the measured values of the nip width and the roll indentation are compared with the corresponding calculated values of the non-linear problem. The nip width is measured by a sensitive sensor film and the roll indentation by a laser displacement sensor. The nonlinear numerical problem is solved using the Finite Element Method with four-node isoparametric quadrilateral elements and Newton-Raphson-type iteration. A suitable form of the constitutive equation and the stress state dependence of the moduli of the incremental stress-strain law will be discussed. A least squares fit to the experimental results determines the values of the paper roll elastic moduli
Long-term clinical and economic outcomes in previously untreated paediatric patients with severe haemophilia A : A nationwide real-world study with 700 person-years
AimFor previously untreated patients (PUPs) with severe haemophilia A in Finland for the past 2 decades, the standard practice has been to start early primary prophylaxis. We evaluated the long-term clinical outcomes and costs of treatment with high-dose prophylaxis in PUPs from birth to adolescence, including immune tolerance induction (ITI). MethodsFrom the medical records of all PUPs born between June 1994 and May 2013 in Finland, we retrospectively extracted data on clinical outcomes and healthcare use. Using linear mixed models, we analysed longitudinal clinical outcome data. To analyse skewed cost data, including zero costs, we applied hurdle regression. ResultsAll 62 patients received early regular prophylaxis; totally, they have had treatment for nearly 700 patient-years. The median age of starting home treatment was 1.1years. The mean (SD) annual treatment costs (Europerkg) were 4391Euro (3852). For ages 1-3, ITI comprised over half of the costs; in other groups, prophylactic FVIII treatment dominated. With these high costs, however, clinical outcomes were desirable; median (IQR) ABR was low at 0.19 (0.07-0.46) and so was AJBR at 0.06 (0-0.24). Thirteen (21%) patients developed a clinically significant inhibitor, 10 (16%) with a high titre. All ITIs were successful. The mean costs for ITI were 383448Euro (259085). The expected ITI payback period was 1.81 (95% CI 0.62-12.12) years. ConclusionsEarly high-dose prophylaxis leads to excellent long-term clinical outcomes, and early childhood ITI therapy seems to turn cost-neutral generally already in 2years.Peer reviewe
Time-course of left ventricle function during mild therapeutic hypothermia in out-of-hospital cardiac arrest patients
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Effect of Inhaled Xenon on Cerebral White Matter Damage in Comatose Survivors of Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial
IMPORTANCE: Evidence from preclinical models indicates that xenon gas can prevent the development of cerebral damage after acute global hypoxic-ischemic brain injury but, thus far, these putative neuroprotective properties have not been reported in human studies. OBJECTIVE: To determine the effect of inhaled xenon on ischemic white matter damage assessed with magnetic resonance imaging (MRI). DESIGN, SETTING, AND PARTICIPANTS: A randomized single-blind phase 2 clinical drug trial conducted between August 2009 and March 2015 at 2 multipurpose intensive care units in Finland. One hundred ten comatose patients (aged 24-76 years) who had experienced out-of-hospital cardiac arrest were randomized. INTERVENTIONS: Patients were randomly assigned to receive either inhaled xenon combined with hypothermia (33°C) for 24 hours (n = 55 in the xenon group) or hypothermia treatment alone (n = 55 in the control group). MAIN OUTCOMES AND MEASURES: The primary end point was cerebral white matter damage as evaluated by fractional anisotropy from diffusion tensor MRI scheduled to be performed between 36 and 52 hours after cardiac arrest. Secondary end points included neurological outcome assessed using the modified Rankin Scale (score 0 [no symptoms] through 6 [death]) and mortality at 6 months. RESULTS: Among the 110 randomized patients (mean age, 61.5 years; 80 men [72.7%]), all completed the study. There were MRI data from 97 patients (88.2%) a median of 53 hours (interquartile range [IQR], 47-64 hours) after cardiac arrest. The mean global fractional anisotropy values were 0.433 (SD, 0.028) in the xenon group and 0.419 (SD, 0.033) in the control group. The age-, sex-, and site-adjusted mean global fractional anisotropy value was 3.8% higher (95% CI, 1.1%-6.4%) in the xenon group (adjusted mean difference, 0.016 [95% CI, 0.005-0.027], P = .006). At 6 months, 75 patients (68.2%) were alive. Secondary end points at 6 months did not reveal statistically significant differences between the groups. In ordinal analysis of the modified Rankin Scale, the median (IQR) value was 1 (1-6) in the xenon group and 1 (0-6) in the control group (median difference, 0 [95% CI, 0-0]; P = .68). The 6-month mortality rate was 27.3% (15/55) in the xenon group and 34.5% (19/55) in the control group (adjusted hazard ratio, 0.49 [95% CI, 0.23-1.01]; P = .053). CONCLUSIONS AND RELEVANCE: Among comatose survivors of out-of-hospital cardiac arrest, inhaled xenon combined with hypothermia compared with hypothermia alone resulted in less white matter damage as measured by fractional anisotropy of diffusion tensor MRI. However, there was no statistically significant difference in neurological outcomes or mortality at 6 months. These preliminary findings require further evaluation in an adequately powered clinical trial designed to assess clinical outcomes associated with inhaled xenon among survivors of out-of-hospital cardiac arrest. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00879892
Evaluating the Assumptions of Surface Reflectance and Aerosol Type Selection Within the MODIS Aerosol Retrieval Over Land: The Problem of Dust Type Selection
Aerosol Optical Depth (AOD) and Angstrom exponent (AE) values derived with the MODIS retrieval algorithm over land (Collection 5) are compared with ground based sun photometer measurements at eleven sites spanning the globe. Although, in general, total AOD compares well at these sites (R2 values generally over 0.8), there are cases (from 2 to 67% of the measurements depending on the site) where MODIS clearly retrieves the wrong spectral dependence, and hence, an unrealistic AE value. Some of these poor AE retrievals are due to the aerosol signal being too small (total AOD<0.3) but in other cases the AOD should have been high enough to derive accurate AE. However, in these cases, MODIS indicates AE values close to 0.6 and zero fine model weighting (FMW), i.e. dust model provides the best fitting to the MODIS observed reflectance. Yet, according to evidence from the collocated sun photometer measurements and back-trajectory analyses, there should be no dust present. This indicates that the assumptions about aerosol model and surface properties made by the MODIS algorithm may have been incorrect. Here we focus on problems related to parameterization of the land-surface optical properties in the algorithm, in particular the relationship between the surface reflectance at 660 and 2130 nm
“Som la Pera,” a School-Based, Peer-Led Social Marketing Intervention to Engage Spanish Adolescents in a Healthy Lifestyle : A Parallel-Cluster Randomized Controlled Study
Acknowledgments This project benefited from valuable collaborations with the National Children's Bureau (the United Kingdom), Companhia de Ideias (Portugal), and Komunikujeme (Czech Republic). The Spanish research project was supported by the Central Market of Reus, Spain (Mercat Central de Reus), which provided fresh food for the intervention, and the Municipality of Reus, Spain [Ajuntament de Reus, Spain]. We thank the teachers, parents, and students of the Reus high schools for their enthusiastic participation in this study. Funding Information This research project was funded by the European Commission (European Directorate General HEALTH-2012 12 19). This funder did not play a role in the Spanish study design, data collection, study management, data analysis, data interpretation, article writing, or decision to submit the report for publication.Peer reviewedPublisher PD
Comparing ECMWF AOD with AERONET observations at visible and UV wavelengths
This paper presents validation results of the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting
System MACC (Monitoring Atmospheric Composition and Climate) re-analysis aerosol optical depth (AOD) for the period 2003–2006.
We evaluate the MACC AOD at a UV wavelength (340 nm) and at
mid-visible (500 and 550 nm) by comparing against ground-based AERONET
measurements at 12 sites. The AERONET sites cover various parts of the globe
and are categorized in three groups: urban/anthropogenic, biomass burning
and dust, depending on the typically dominating aerosol type. This is the
first time a global model such as the ECMWF has been evaluated for the
performance of AOD at a UV wavelength. The results show that the MACC system
generally provides a good representation of the AOD on a monthly basis,
showing a realistic seasonal cycle. The model is mostly able to capture
major dust load events and also the peak months of biomass burning
correctly. For Kanpur and Solar Village, however, the model overestimates
the AOD during the monsoon period when the aerosol load is generally low.
When comparing hourly AOD values, the model–measurement agreement is better
for biomass burning and dust sites than for urban sites, with an average
correlation coefficient around 0.90 for biomass burning sites, around 0.77
for dust sites, and below 0.70 for urban sites. The AOD at 500 nm averaged
over all sites shows only a small systematic difference between modeled and
measured values, with a relative mean bias of 0.02. However, for the AOD at
340 nm the relative mean bias is −0.2. All sites included in the study show
a relative mean bias at 340 nm smaller (or more negative) than that at 500 nm, indicating a strong wavelength dependence in the performance of the AOD
in the MACC system. A comparison against fine and coarse mode AOD of the
AERONET indicates that this has to do with the size distribution of the
model: generally, the ECMWF model overestimates the contribution by coarse
mode particles
Solar UV irradiance in a changing climate: Trends in europe and the significance of spectral monitoring in Italy
Review of the existing bibliography shows that the direction and magnitude of the long-term trends of UV irradiance, and their main drivers, vary significantly throughout Europe. Analysis of total ozone and spectral UV data recorded at four European stations during 1996–2017 reveals that long-term changes in UV are mainly driven by changes in aerosols, cloudiness, and surface albedo, while changes in total ozone play a less significant role. The variability of UV irradiance is large throughout Italy due to the complex topography and large latitudinal extension of the country. Analysis of the spectral UV records of the urban site of Rome, and the alpine site of Aosta reveals that differences between the two sites follow the annual cycle of the differences in cloudiness and surface albedo. Comparisons between the noon UV index measured at the ground at the same stations and the corresponding estimates from the Deutscher Wetterdienst (DWD) forecast model and the ozone monitoring instrument (OMI)/Aura observations reveal differences of up to 6 units between individual measurements, which are likely due to the different spatial resolution of the different datasets, and average differences of 0.5–1 unit, possibly related to the use of climatological surface albedo and aerosol optical properties in the retrieval algorithms
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