Viscoelastic models can be used to better understand arterial wall mechanics in physiological and pathological conditions. The arterial wall reveals very slow time-dependent decays in uniaxial ...stress-relaxation experiments, coherent with weak power-law functions. Quasi-linear viscoelastic (QLV) theory was successfully applied to modeling such responses, but an accurate estimation of the reduced relaxation function parameters can be very difficult. In this work, an alternative relaxation function based on fractional calculus theory is proposed to describe stress relaxation experiments in strips cut from healthy human aortas. Stress relaxation (1 h) was registered at three incremental stress levels. The novel relaxation function with three parameters was integrated into the QLV theory to fit experimental data. It was based in a modified Voigt model, including a fractional element of order alpha, called spring-pot. The stress-relaxation prediction was accurate and fast. Sensitivity plots for each parameter presented a minimum near their optimal values. Least-squares errors remained below 2%. Values of order alpha = 0.1-0.3 confirmed a predominant elastic behavior. The other two parameters of the model can be associated to elastic and viscous constants that explain the time course of the observed relaxation function. The fractional-order model integrated into the QLV theory proved to capture the essential features of the arterial wall mechanical response.
The excited states of unstable ^{20}O were investigated via γ-ray spectroscopy following the ^{19}O(d,p)^{20}O reaction at 8 AMeV. By exploiting the Doppler shift attenuation method, the lifetimes ...of the 2_{2}^{+} and 3_{1}^{+} states were firmly established. From the γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+} and 3_{1}^{+} states, the B(E2) and B(M1) were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of γ-ray transition probabilities with the valence space in medium similarity renormalization group ab initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab initio approaches using chiral effective field theory forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab initio models.
Air pollution in large cities produces numerous diseases and even millions of deaths annually according to the World Health Organization. Pollen exposure is related to allergic diseases, which makes ...its prediction a valuable tool to assess the risk level to aeroallergens. However, airborne pollen concentrations are difficult to predict due to the inherent complexity of the relationships among both biotic and environmental variables. In this work, a stochastic approach based on supervised machine learning algorithms was performed to forecast the daily
Olea
pollen concentrations in the Community of Madrid, central Spain, from 1993 to 2018. Firstly, individual Light Gradient Boosting Machine (LightGBM) and artificial neural network (ANN) models were applied to predict the day of the year (DOY) when the peak of the pollen season occurs, resulting the estimated average peak date 149.1 ± 9.3 and 150.1 ± 10.8 DOY for LightGBM and ANN, respectively, close to the observed value (148.8 ± 9.8). Secondly, the daily pollen concentrations during the entire pollen season have been calculated using an ensemble of two-step GAM followed by LightGBM and ANN. The results of the prediction of daily pollen concentrations showed a coefficient of determination (
r
2
) above 0.75 (goodness of the model following cross-validation). The predictors included in the ensemble models were meteorological variables, phenological metrics, specific site-characteristics, and preceding pollen concentrations. The models are state-of-the-art in machine learning and their potential has been shown to be used and deployed to understand and to predict the pollen risk levels during the main olive pollen season.
Silicon substituted and nanocrystalline hydroxyapatites have attracted the attention of many researchers due to their up-regulation in osteoblast cell metabolism and enhanced bioreactivity, ...respectively. On the other hand, the biomaterial success or failure depends ultimately on the immune response triggered after its implantation. Macrophages are the main components of the innate immune system with an important role in healing and tissue remodelling due to their remarkable functional plasticity, existing in a whole spectrum of functional populations with varying phenotypic features. The effects of nanocrystalline hydroxyapatite (nano-HA) and nanocrystalline silicon substituted hydroxyapatite (nano-SiHA) on the macrophage populations defined as pro-inflammatory (M1) and reparative (M2) phenotypes have been evaluated in the present study using RAW 264.7 cells and mouse peritoneal macrophages as
in vitro
models. M1 and M2 macrophage phenotypes were characterized by flow cytometry and confocal microscopy by the expression of CD80 and CD163, known as M1 and M2 markers, respectively. The polarization of primary macrophages towards the M1 or M2 phenotype was induced with the pro-inflammatory stimulus LPS or the anti-inflammatory stimulus IL-10, respectively, evaluating the biomaterial effects under these conditions. Our results show that both nano-HA and nano-SiHA favour the macrophage polarization towards an M2 reparative phenotype, decreasing M1 population and ensuring an appropriate response in the implantation site of these biomaterials designed for bone repair and bone tissue engineering.
Nanocrystalline hydroxyapatites favour the macrophage polarization towards a M2 reparative phenotype, ensuring an appropriate response in the implantation site.
Composites are prepared by deposition of nanoparticles of RuO
2·
xH
2O (1–4
nm) on two carbons: microporous carbon (1.3
nm of average micropore size) and mesoporous carbon (11
nm of average mesopore ...size). Two-preparation procedures are used: (i) procedure A consisting of repetitive impregnations of the carbons with RuCl
3·0.5H
2O solutions, and (ii) procedure B based on impregnation of the carbons with Ru(acac)
3 vapour. The procedure B leads to supported RuO
2·
xH
2O particles that appear more crystalline than those obtained by the procedure A. Specific capacitance and specific surface area of the composites are discussed as functions of the RuO
2 content, and different dependences for the composites derived from the two carbons are found. Mesoporous carbon is better support than microporous carbon. Procedure A leads to supported RuO
2·
xH
2O particles with higher specific capacitance than the particles deposited by procedure B.
A safety threshold for baseline rhythm R-wave amplitudes during follow-up of implantable cardioverter defibrillators (ICD) has not been established. We aimed to analyse the amplitude distribution and ...undersensing rate during spontaneous episodes of ventricular fibrillation (VF), and define a safety amplitude threshold for baseline R-waves.
Data were obtained from an observational multicentre registry conducted at 48 centres in Spain. Baseline R-wave amplitudes and VF events were prospectively registered by remote monitoring. Signal processing algorithms were used to compare amplitudes of baseline R-waves with VF R-waves. All undersensed R-waves after the blanking period (120 ms) were manually marked.
We studied 2507 patients from August 2011 to September 2014, which yielded 229 VF episodes (cycle length 189.6±29.1 ms) from 83 patients that were suitable for R-wave comparisons (follow-up 2.7±2.6 years). The majority (77.6%) of VF R-waves (n=13953) showed lower amplitudes than the reference baseline R-wave. The decrease in VF amplitude was progressively attenuated among subgroups of baseline R-wave amplitude (≥17; ≥12 to <17; ≥7 to <12; ≥2.2 to <7 mV) from the highest to the lowest: median deviations -51.2% to +22.4%, respectively (p=0.027). There were no significant differences in undersensing rates of VF R-waves among subgroups. Both the normalised histogram distribution and the undersensing risk function obtained from the ≥2.2 to <7 mV subgroup enabled the prediction that baseline R-wave amplitudes ≤2.5 mV (interquartile range: 2.3-2.8 mV) may lead to ≥25% of undersensed VF R-waves.
Baseline R-wave amplitudes ≤2.5 mV during follow-up of patients with ICDs may lead to high risk of delayed detection of VF.
NCT01561144; results.
Caregiving can be a stressful task with severe consequences on caregivers' health. Our aim was to evaluate the profile and the burden of caregivers of patients with home artificial nutrition (HAN) in ...our area.
We conducted a prospective observational study of patients who had started HAN over a period of a year (n=573) and their home caregivers (n=103). Epidemiological characteristics of the patients and the type of HAN were registered. Caregivers' profile data (gender, age and degree of kinship) and Zarit Burden Assessments were recorded.
Care recipients had a median age of 79.0 (IQR 87) years, neurological and oncological diseases in 50% and a high rate of mobility limitations (80%). Oral supplements with high-calorie formulas were predominant (60%). The usual caregiver profile was a patient's daughter with a mean age of 53.1 (s.d. 13.4) years acting as the primary caregiver. Burden was absent in 49.5%, light in 18.4% and intense in 32% of caregivers. Intense burden was more frequent in oral over enteral nutrition (42% versus 22.6%; P=0.036). Supplementary nutrition was also associated with higher caregiver burden scores compared with complete diets. In patients with functional limitations, a tendency toward a slightly higher burden was observed. No differences in caregiver burden were detected according to other patient or caregiver characteristics.
HAN type appears to be a factor influencing caregiver burden and therefore, evaluation of caregiver burden should be part of HAN programs.
Abstract There is a lack of valid instruments to measure empowerment in Spanish-speaking populations. This study aimed to adapt the Netherlands Empowerment List (NEL), a 40-item scale, into Spanish ...and to test its psychometric properties examining its dimensional structure, internal consistency, temporal stability, relationships with other variables, and differential item functioning by gender. Participants were 406 users of mental health community rehabilitation services (52.5% male), with a mean age of 47.8 years. Results confirmed a six first-order factor structure of the scale. Internal consistency was excellent for the total score and ranged from excellent to adequate for subscale scores. Temporal stability was excellent for four subscales and good for the remaining two. The analysis of relationships between the Spanish NEL with other variables (i.e., empowerment, recovery, hope, perceived social support) provided additional evidence of its validity. Although four items showed uniform differential item functioning by gender, the effect size was negligible. The Spanish NEL yields valid and reliable scores, and it may be used to assess empowerment in Spanish-speaking countries.
As-grown and modified single-walled carbon nanotubes (SWCNTs) have been used as electrochemical active materials of electrode for electrochemical capacitors (supercapacitors). A series of modified ...SWCNTs has been obtained by oxidation of the as-grown SWCNTs in air at increasing temperatures in the range 300-550DGC. The as-grown and modified samples have been characterized by Raman spectroscopy, N2 adsorption, and transmission electron microscopy (TEM). Raman spectra of the modified samples show that heating at increasing temperature produces a decrease in the intensity of radial and tangential breathing modes of SWCNTs and an alteration of the structure of SWCNTs up to complete destruction at 550DGC. Heat-treatment at 350DGC leads to the highest specific surface area (644 m2 g-1) and the highest micropore volume (0.288 cm3 g-1). TEM images of the as-grown and 350DGC-oxidized samples show a multicomponent structure with bundles of SWCNTs that are thinner in the oxidized sample compared to the as-grown one. The as-grown and 350DGC-oxidized SWCNTs were mixed with polyvinylidenefluoride and compacted to get electrodes. 6 M KOH and 2 M H2SO4 aqueous solutions were utilized as electrolytes. The specific capacitances (30-140 F g-1) are discussed on the basis of the electrode material and the electrolyte chosen. The specific capacitance is higher for the 350DGC-oxidized SWCNTs and when KOH is used as electrolyte. Typical values of the equivalent series resistance (ESR) are in the range 1-5 Omega, except for the oxidized sample when KOH is used as electrolyte; in this case, ESR is higher. The thermal treatment improves the energy density but does not affect the power density, this last being higher when H2SO4 is used.
PDF
