76 research outputs found
On the behavior of CTAB/CTAOH adlayers on gold single crystal surfaces
The behavior of adsorbed CTAB and CTAOH on gold single crystal electrodes has been studied in solutions with different pH values. For the different single crystal electrodes, the adsorbed adlayer formed by CTA+ cations is in contact with the surface, when the electrode charge is negative. As the surface charge becomes positive, the adlayer detaches from the surface and water molecules permeate through it, giving rise to characteristic peaks in the voltammogram. Charge and laser induced jump temperature measurements show that the composition of the adlayer contains not only the CTA+ cations but also anions, which are required to stabilize the adlayer. In alkaline solutions, the higher solubility of CTAB/CTAOH in alkaline solutions leads to the partial desorption of the adlayer when these species are not present in the solution. When CTAB or CTAOH are dissolved in the alkaline cell solution, the adlayer is strongly bonded to the surface in the whole potential window due to the negative charge of the surface.Financial support from Ministerio de Ciencia e InnovaciĂłn (Project PID2019-105653GB-I00) and Generalitat Valenciana (Project PROMETEO/2020/063) is acknowledged
Effects and Optimal Dose of Exercise on Endothelial Function in Patients with Heart Failure: A Systematic Review and MetaâAnalysis
Background Exercise-based cardiac rehabilitation (CR) is considered an effective treatment for enhancing endothelial function in patients with heart failure (HF). However, recent studies have been published and the optimal âdoseâ of exercise required to increase the benefits of exercise-based CR programmes on endothelial function is still unknown.
Objectives (a) To estimate the effect of exercise-based CR on endothelial function, assessed by flow-mediated dilation (FMD), in patients with HF; (b) to determine whether high-intensity interval training (HIIT) is better than moderate-intensity training (MIT) for improving FMD; and (c) to investigate the influence of exercise modality (i.e. resistance exercise vs. aerobic exercise and combined exercise vs. aerobic exercise) on the improvement of endothelial function.
Methods Electronic searches were carried out in PubMed, Embase, and Scopus up to February 2022. Random-effects models of between-group mean differences were estimated. Heterogeneity analyses were performed by means of the chi-square test and I2 index. Subgroup analyses and meta-regressions were used to test the influence of potential moderator variables on the effect of exercise.
Results We found a FMD increase of 3.09% (95% confidence interval [CI] = 2.01, 4.17) in favour of aerobic-based CR programmes compared with control groups in patients with HF and reduced ejection fraction (HFrEF). However, the results of included studies were inconsistent (p < .001; I2 = 95.2%). Higher FMD improvement was found in studies which were randomised, reported radial FMD, or performed higher number of training sessions a week. Moreover, HIIT enhanced FMD to a greater extent than MIT (2.35% [95% CI = 0.49, 4.22]) in patients with HFrEF. Insufficient data prevented pooled analyses for the effect of exercise in patients with HF and preserved ejection fraction and the influence of exercise modality on the improvement of endothelial function.
Conclusion Aerobic-based CR is a non-pharmacological treatment for enhancing endothelial function in patients with HFrEF. However, higher training frequency and HIIT induce greater adaptation of endothelial function in these patients, which should betaken into consideration when designing exercise-based CR programmes. Trial registration The protocol was prospectively registered on the PROSPERO database (CRD42022304687)
Effects of high-intensity interval training on vascular function in patients with cardiovascular disease: a systematic review and meta-analysis
Background: Exercise training improves endothelial function in patients with
cardiovascular disease (CVD). However, the influence of training variables
remains unclear. The aim of this study was to evaluate the effect of highintensity
interval training (HIIT), compared to moderate intensity training (MIT)
and other exercise modalities (i.e., resistance and combined exercise), on
endothelial function, assessed by arterial flow-mediated dilation (FMD) or
endothelial progenitor cells (EPCs), in patients with CVD. Secondly, we
investigated the influence of other training variables (i.e., HIIT protocol).
Methods: The PICOS strategy was used to identify randomised and nonrandomised
studies comparing the effect of HIIT and other exercise modalities
(e.g., MIT) on endothelial function in patients with CVD. Electronic searches were
carried out in Pubmed, Embase, and Web of Science up to November 2022. The
TESTEX scale was used to evaluate the methodological quality of the included
studies. Random-effects models of between-group mean difference (MD) were
estimated. A positive MD indicated an effect in favour of HIIT. Heterogeneity
analyses were performed by the chi-square test and I2 index. Subgroup analyses
evaluated the influence of potential moderator variables.
Results: Fourteen studies (13; 92.9% randomised) were included. Most of the
studies trained 3 days a week for 12 weeks and performed long HIIT. No
statistically significant differences were found between HIIT and MIT for
improving brachial FMD in patients with coronary artery disease (CAD) and
heart failure with reduced ejection fraction (HFrEF) (8 studies; MD+ = 0.91%
[95% confidence interval (CI) = â0.06, 1.88]). However, subgroup analyses
showed that long HIIT (i.e., > 1 min) is better than MIT for enhancing FMD
(5 studies; MD+ = 1.46% [95% CI = 0.35, 2.57]), while no differences were
found between short HIIT (i.e., †1 min) and MIT (3 studies; MD+ = â0.41%
[95% CI = â1.64, 0.82]). Insufficient data prevented pooled analysis for EPCs,
and individual studies failed to find statistically significant differences (p > .050)
between HIIT and other exercise modalities in increasing EPCs. Discussion: Poor methodological quality could limit the precision of the current
results and increase the inconsistency. Long HIIT is superior to MIT for improving
FMD in patients with CAD or HFrEF. Future studies comparing HIIT to other exercise
modalities, as well as the effect on EPCs and in HF with preserved ejection fraction
are required
Working together: a review on safe human-robot collaboration in industrial environments
After many years of rigid conventional procedures of production, industrial manufacturing is going through a process of change toward flexible and intelligent manufacturing, the so-called Industry 4.0. In this paper, human-robot collaboration has an important role in smart factories since it contributes to the achievement of higher productivity and greater efficiency. However, this evolution means breaking with the established safety procedures as the separation of workspaces between robot and human is removed. These changes are reflected in safety standards related to industrial robotics since the last decade, and have led to the development of a wide field of research focusing on the prevention of human-robot impacts and/or the minimization of related risks or their consequences. This paper presents a review of the main safety systems that have been proposed and applied in industrial robotic environments that contribute to the achievement of safe collaborative human-robot work. Additionally, a review is provided of the current regulations along with new concepts that have been introduced in them. The discussion presented in this paper includes multidisciplinary approaches, such as techniques for estimation and the evaluation of injuries in human-robot collisions, mechanical and software devices designed to minimize the consequences of human-robot impact, impact detection systems, and strategies to prevent collisions or minimize their consequences when they occur
Bayesian estimation of incomplete data using conditionally specified priors
In this paper, a class of conjugate prior for estimating incomplete count data based on a broad class of conjugate prior distributions is presented. The new class of prior distributions arises from a conditional perspective, making use of the conditional specification methodology and can be considered as the generalisation of the form of prior distributions that have been used previously in the estimation of in- complete count data well. Finally, some examples of simulated and real data are given
International Physical Activity Questionnaire Short Form and accelerometer-assessed physical activity: concurrent validity using six cut-points in HF patients
Aims Physical activity (PA) is an important target for improving clinical outcomes in heart failure (HF) patients. Nonetheless, assessing the daily PA profile in this population is a challenging task, traditionally performed using self-report questionnaires such as the International PA Questionnaire Short Form (IPAQ-SF). This study aimed to evaluate the concurrent validity of the IPAQ-SF and accelerometer-assessed PA using six published cut-points in patients with HF and reduced or mildly reduced ejection
fraction.
Methods and results The concordance between the IPAQ-SF and a hip-worn accelerometer regarding daily time spent performing moderate to vigorous PA in bouts of at least 10 min was assessed in 53 participants for seven consecutive days using six different cut-points (Barnett, Dibben, Mark, Sanders, Troiano, and Vaha-Ypya). Spearmanâs correlation and BlandâAltman plots were used to evaluate concurrent validity between methods. Regressions were used to study the association between patient variables, wear protocol (waking hour or 24 h), and absolute bias. The kappa index was used to evaluate the concordance between IPAQ-SF and accelerometry for classifying patients as active or non-active. All analyses were re-run using non-bouted metrics to investigate the effect of bouted versus non-bouted analysis. The IPAQ-SF and accelerometry showed
low to negligible correlation (Ï = 0.12 to 0.37), depending on the cut-point used. The regression analysis showed that the absolute bias was higher in participants following the waking-hour protocol at all cut-points except Dibbenâs (P †0.007). The concordance between the two methods to classify patients as active and non-active was low when using Mark (Îș = 0.23) and Barnett (Îș = 0.34) cut-points and poor for the remaining cut-points (Îș = 0.03 to 0.18). The results of the sensitivity analysis showed negligible to low correlation using non-bouted metrics (Ï = 0.27 to 0.33). Conclusions Moderate to vigorous PA measures using IPAQ-SF and accelerometers are not equivalent, and we do not encourage researchers to use IPAQ-SF alone when assessing PA in HF patients. Moreover, applying personalized collection and processing criteria is important when assessing PA in HF patients. We recommend following the 24 h protocol and selecting cut-points calibrated in patients with cardiovascular diseases. Finally, it is necessary to develop a new tailored questionnaire
that considers walking intensity and is adjusted to the current World Health Organisation recommendations, which use non-bouted metrics
Coherent Bragg imaging of 60â nm Au nanoparticles under electrochemical control at the NanoMAX beamline
Nanoparticles are essential electrocatalysts in chemical production, water treatment and energy conversion, but engineering efficient and specific catalysts requires understanding complex structureâreactivity relations. Recent experiments have shown that Bragg coherent diffraction imaging might be a powerful tool in this regard. The technique provides three-dimensional lattice strain fields from which surface reactivity maps can be inferred. However, all experiments published so far have investigated particles an order of magnitude larger than those used in practical applications. Studying smaller particles quickly becomes demanding as the diffracted intensity falls. Here, in situ nanodiffraction data from 60â
nm Au nanoparticles under electrochemical control collected at the hard X-ray nanoprobe beamline of MAX IV, NanoMAX, are presented. Two-dimensional image reconstructions of these particles are produced, and it is estimated that NanoMAX, which is now open for general users, has the requisites for three-dimensional imaging of particles of a size relevant for catalytic applications. This represents the first demonstration of coherent X-ray diffraction experiments performed at a diffraction-limited storage ring, and illustrates the importance of these new sources for experiments where coherence properties become crucial.This work was supported by the AForsk Foundation through grant 17-408. JS-G acknowledges financial support from VITC (Vicerrectorado de InvestigaciĂłn y Transferencia de Conocimiento) of the University of Alicante (UATALENTO16-02). The MAX IV Laboratory receives funding through the Swedish Research Council under grant no 2013-02235
Inventario de Daños y Efectos GeolĂłgicos Co y/o Post-SĂsmicos del Sismo Ocurrido el 18 de mayo de 1875, en la Frontera entre Colombia y Venezuela
On the border between Colombia and Venezuela, have occurred seismic events with important records of damage in both countries. In this paper, we study the historical earthquake that took place on May 18, 1875 between 11.15 and 11.30 in the morning (the time was the same for communities in both countries since there was no time zone difference), which is catalogued as a border earthquake due to the report of damages in the cities of both nations. The community of San JosĂ© de CĂșcuta, current capital of the Northern State of Santander, Colombia, registered the greatest number of deaths and damage to buildings.
An inventory of the geological damage and co -seismic and postseismic effects was created based on information of previous studies and data obtained from archival primary sources from Colombia and Venezuela. The result is a bi-national database, which includes the summaries of historical descriptions with the effects in the persons and objects, the geological damages and effects observed during the seismic event. These data has led to the creation of a table of MM and EMS-98 intensities, which enables the identification and delimitation of the regions of greater damages. The maximum level intensity is I=10 in the cities of San JosĂ© de CĂșcuta, Villa del Rosario, Pueblo de CĂșcuta (San Luis) in Colombia and San Antonio, San Juan de Ureña in Venezuela. Moreover, we formulated a table of intensities using the ESI-2007 INQUA scale, based on the information of geological observations described in historical documents. These data are related to the epicentral zone with an approximate radius of 30 km.Published105-2635T. Sismologia, geofisica e geologia per l'ingegneria sismicaN/A or not JC
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