Search

Objective: To ascertain the changes of serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) values in relapsing–remitting multiple sclerosis (RRMS) patients treated with ocrelizumab and their association with treatment response. Methods: Multicenter prospective study including 115 RRMS patients initiating ocrelizumab treatment between February 2020 and March 2022 followed during a year. Serum samples were collected at baseline and every 3 months to measure sNfL and sGFAP levels using single-molecule array (SIMOA) technology. Based on age and body mass index, sNfL values were standardized using z-score. NEDA (non-evidence of disease activity)-3 status was defined for patients free of disease activity after a year of follow-up. Inflammation (INFL) was considered when new relapses occurred during follow-up or new MRI lesions were found at 1-year exploration. PIRA (progression independent of relapse activity) was defined as disability progression occurring in the absence of relapses or new MRI activity. Results: After a year on ocrelizumab, 85 patients (73.9%) achieved NEDA-3. Thirty patients did not achieve NEDA: 20 (17.4%) because of INFL and 10 (8.7%) because of PIRA. Of INFL patients, 6 (30.0%) had relapses, and 17 (85.0%) had at least one new MRI lesion at the 12-month examination. At baseline, INFL patients had higher sNfL (p = 0.0003) and sGFAP (p = 0.03) than the NEDA-3 group. PIRA patients mostly exhibited low sNfL and heterogeneous sGFAP levels. After a year, NEDA-3 and INFL patients showed similar decreases in sNfL (p < 0.0001) and sGFAP (p < 0.0001 for NEDA-3 and p = 0.001 for INFL ones). However, the decrease occurred earlier in NEDA-3 patients. Accordingly, sNfL > 1.5 z-score 3 months after ocrelizumab initiation indicated a higher risk of inflammation (OR = 13.6; p < 0.0001). Decrease in sGFAP values occurred later in both groups, with significant reductions observed at 12 months for INFL and 6 and 12 months for NEDA-3. No significant changes in sNfL or sGFAP were observed in PIRA patients. Conclusion: Ocrelizumab induced normalization of sNfL and sGFAP in the majority of NEDA-3 and inflammatory patients but did not cause changes in the PIRA group. Our data suggest that normalization of sNfL and sGFAP is associated with the lack of inflammatory-associated disease progression but it may not affect non-inflammatory PIRA. [ABSTRACT FROM AUTHOR]

Objective: To ascertain the changes of serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) values in relapsing–remitting multiple sclerosis (RRMS) patients treated with ocrelizumab and their association with treatment response. Methods: Multicenter prospective study including 115 RRMS patients initiating ocrelizumab treatment between February 2020 and March 2022 followed during a year. Serum samples were collected at baseline and every 3 months to measure sNfL and sGFAP levels using single-molecule array (SIMOA) technology. Based on age and body mass index, sNfL values were standardized using z-score. NEDA (non-evidence of disease activity)-3 status was defined for patients free of disease activity after a year of follow-up. Inflammation (INFL) was considered when new relapses occurred during follow-up or new MRI lesions were found at 1-year exploration. PIRA (progression independent of relapse activity) was defined as disability progression occurring in the absence of relapses or new MRI activity. Results: After a year on ocrelizumab, 85 patients (73.9%) achieved NEDA-3. Thirty patients did not achieve NEDA: 20 (17.4%) because of INFL and 10 (8.7%) because of PIRA. Of INFL patients, 6 (30.0%) had relapses, and 17 (85.0%) had at least one new MRI lesion at the 12-month examination. At baseline, INFL patients had higher sNfL (p = 0.0003) and sGFAP (p = 0.03) than the NEDA-3 group. PIRA patients mostly exhibited low sNfL and heterogeneous sGFAP levels. After a year, NEDA-3 and INFL patients showed similar decreases in sNfL (p < 0.0001) and sGFAP (p < 0.0001 for NEDA-3 and p = 0.001 for INFL ones). However, the decrease occurred earlier in NEDA-3 patients. Accordingly, sNfL > 1.5 z-score 3 months after ocrelizumab initiation indicated a higher risk of inflammation (OR = 13.6; p < 0.0001). Decrease in sGFAP values occurred later in both groups, with significant reductions observed at 12 months for INFL and 6 and 12 months for NEDA-3. No significant changes in sNfL or sGFAP were observed in PIRA patients. Conclusion: Ocrelizumab induced normalization of sNfL and sGFAP in the majority of NEDA-3 and inflammatory patients but did not cause changes in the PIRA group. Our data suggest that normalization of sNfL and sGFAP is associated with the lack of inflammatory-associated disease progression but it may not affect non-inflammatory PIRA. [ABSTRACT FROM AUTHOR]

The correction notice in the journal "Frontiers in Immunology" addresses an error in the spelling of an author's name, correcting "Fernando Castellanos" to "Fernando Castellanos-Pinedo." The authors acknowledge the mistake but clarify that it does not impact the scientific conclusions of the article. The document lists all authors involved in the study on biomarkers of response to ocrelizumab in relapsing-remitting multiple sclerosis. [Extracted from the article]

In this paper, two different methodologies are applied to the parameter estimation problem of a computational model of a Round-Robin test box. The numerical model is developed using TRNSYS. A global sensitivity analysis is carried out to determine the most important parameters that should be considered in the subsequent calibration procedure. Using the Bayesian (probabilistic) approach, the posterior distribution of the unknown input parameters is estimated via simulation techniques. Using the deterministic approach, executed in GenOpt, the calibration is performed by the minimization of an objective function that measures the differences between model predictions and real measured data. Parameter estimation results obtained with both methodologies are then compared and discussed. A reduction of the Coefficient of Variation of the Root Mean Square Error (CV (RMSE)) after calibration over 40% with both methods has been obtained, being the CV (RMSE) for calibration and validation periods on average 3.21% and 2.40%, respectively. [ABSTRACT FROM AUTHOR]

In this work, fouling and bottom ash were collected from a low-power boiler after wood pellet combustion and studied using several analytical techniques to characterize and compare samples from different areas and determine the suitability of the analysis techniques employed. TGA results indicated that the fouling contained a high amount of organic matter (70%). The XRF and SEM-EDS measurements revealed that Ca and K are the main inorganic elements and exhibit clear tendency in the content of Cl that is negligible in the bottom ash and increased as it penetrated into the innermost layers of the fouling. Calcite, magnesia and silica appeared as the major crystalline phases in all the samples. However, the bottom ash was primarily comprised of calcium silicates. The KCl behaved identically to the Cl, preferably appeared in the adhered fouling samples. This salt, which has a low melting point, condenses upon contact with the low temperature tube and played a crucial role in the early stages of fouling formation. XRD was the most useful technique applied, which provided a semi-quantitative determination of the crystalline phases. FTIR was proven to be inadequate for this type of sample. The XRF and SEM-EDS, techniques yield similar results despite being entirely different. [ABSTRACT FROM AUTHOR]

Although the Stirling engine was invented in 1816, this heat engine still continues to be investigated due to the variety of energy sources that can be used to power it (e.g., solar energy, fossil fuels, biomass, and geothermal energy). To study the performance of these machines, it is necessary to develop and simulate models under different operating conditions. In this paper, we present a one-dimensional dynamic model based on components from Trnsys: principally, a lumped mass and a heat exchanger. The resulting model is calibrated using GenOpt. Furthermore, the obtained model can be used to simulate the machine both under steady-state operation and during a transient response. The results provided by the simulations are compared with data measured in a Stirling engine that has been subjected to different operating conditions. This comparison shows good agreement, indicating that the model is an appropriate method for transient thermal simulations. This new proposed model requires few configuration parameters and is therefore easily adaptable to a wide range of commercial models of Stirling engines. A detailed analysis of the system results reveals that the power is directly related to the difference of temperatures between the hot and cold sources during the transient and steady-state processes. [ABSTRACT FROM AUTHOR]

Many researchers have been working in Spain to document the communal graves of those assassinated during the Spanish Civil War. This article shows the results obtained with two low-cost photogrammetric techniques for the basic documentation of forensic studies. These low-cost techniques are based on single-image rectification and the correction of the original photo displacement due to the projection and perspective distortions introduced by the lens of the camera. The capability of image rectification is tested in an excavation in the village of Loma de Montija ( Burgos, Spain). The results of both techniques are compared with the more accurate data obtained from a laser scanner system RIEGL LMS-Z390i to evaluate the error in the lengths. The first technique uses a camera situated on a triangle-shaped pole at a height of 5 m and the second positions the camera over the grave using a linearly actuated device. The first technique shows measurement errors less than 6%, whereas the second shows greater errors (between 8% and 14%) owing to the positioning of the carbon-fiber cross on an uneven surface. [ABSTRACT FROM AUTHOR]

This article describes a simple model obtained from a commercial Stirling engine and used for heating a caravan. The Stirling engine has been tested in the lab under different electrical load conditions, and the operating points obtained are presented. As an application of the model, a series of transient simulations was performed using TRNSYS. During these simulations, the caravan is traveling throughout the day and is stationary at night. Therefore, during the night-time hours, the heating system is turned on by means of the Stirling engine. The study was performed for each month of the year in different European cities. The different heating demand profiles for different cities induce variation in the electricity production, as it has been assumed that electricity is only generated when the thermal demand requires the operation of the Stirling system. As a result, a comparison of the expected power generation in different European cities is presented. [ABSTRACT FROM AUTHOR]

An experimental analysis of the ignition front propagation of eight biomass fuels in a one-dimensional fixed-bed combustor (batch reactor) is carried out and these biomass materials are also researched by thermogravimetry to study their thermal behaviour during devolatilization. The analysis of the thermogravimetric data has been centered on the results obtained for 50 °C · min-1 (maximun heating rate of the thermogravimetric (TG) equipment), taking into consideration that it is the nearest heating rate value to the one at which the heating process is carried out in the batch reactor. The influence of the TG-determined devolatilization rate in the burning behaviour of biomass in situations of packed bed combustion is analyzed. This study reveals that the biomass fuels with higher devolatilization rates during pyrolysis are the ones with a higher velocity of propagation of the ignition front during combustion processes in the fixed-bed combustor. The thermal decomposition characteristics during devolatilization are also evaluated, revealing that the most reactive biomass fuels upon pyrolysis are the ones which also produce the higher volatile yield during TG experiments at 50 °C · min-1. [ABSTRACT FROM AUTHOR]

In this work, a CFD-based model is proposed to analyse the effect of phase change materials (PCMs) on the thermal behaviour of the walls of a cubicle exposed to the environment and on the resistance of the walls to climate changes. The effect of several days of exposure to the environment was simulated using the proposed method. The results of the simulation are compared with experimental data to contrast the models. The effects of exposure on the same days were simulated for several walls of a cubicle made of a mixture of concrete and PCM. The results show that the PCM stabilizes temperatures within the cubicle and decreases energy consumption of refrigeration systems. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to simulate the combustion of fixed beds of biomass particles using computational fluid dynamics (CFD) techniques. The models presented were used in the simulation of a domestic pellet boiler working under operating conditions and the model predictions were compared with measurements of heat transfer, temperature and species concentration. The same procedure was then used to simulate the same domestic boiler working with different values of water temperature and the influence of water temperature variations on the main variables was analyzed. [ABSTRACT FROM AUTHOR]

PEM fuel cells are nonlinear, multi-input and multi-output, time-varying, and strongly coupled systems that are hard to model via conventional methods. A suitable model is needed for PEM fuel cells to predict how they will behave under various operating conditions. Usually, modelling of fuel cell systems requires a good knowledge of the parameters involved in the processes that, in many cases, are difficult to determine. A solution to avoid this difficulty consists in using black-box models, such as those based on artificial neural networks (ANN). This paper presents the modelling of a PEM fuel cell system, using ANNs. The selected ANN structure has been validated for the transient state, during the start up of the system, and in steady state. Results are shown for a commercial PEM fuel cell system. The ANN model developed can be applied to any PEM fuel cell, applying the principle of similarity. [ABSTRACT FROM AUTHOR]

This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD) web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes. [ABSTRACT FROM AUTHOR]

This paper investigates a method for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG analysis) for several lignocellulosic materials (ground olive stone, almond shell, pine pellets and oak pellets), completing previous work of the same authors. A comparison has been made between results of TG analysis and prompt analysis. Levels of uncertainty and errors were obtained, demonstrating that properties evaluated by TG analysis were representative of the overall fuel composition, and no correlation between prompt and TG analysis exists. Additionally, a study of trends and time correlations is indicated. These results are particularly interesting for biomass energy applications. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a methodology for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG), including moisture, volatile matter, fixed carbon and ash content. The sampling procedure of the TG analysis was of particular interest and was conducted with care. The results of the present study were compared to those of a prompt analysis, and a correlation between the mean values and maximum sampling errors of the methods were not observed. In general, low and acceptable levels of uncertainty and error were obtained, demonstrating that the properties evaluated by TG analysis were representative of the overall fuel composition. The accurate determination of the thermal properties of biomass with precise confidence intervals is of particular interest in energetic biomass applications. [ABSTRACT FROM AUTHOR]