1,344 research outputs found
Introducing alternative-based thresholding for defining functional regions of interest in fMRI
In fMRI research, one often aims to examine activation in specific functional regions of interest (fROIs). Current statistical methods tend to localize fROIs inconsistently, focusing on avoiding detection of false activation. Not missing true activation is however equally important in this context. In this study, we explored the potential of an alternative-based thresholding (ABT) procedure, where evidence against the null hypothesis of no effect and evidence against a prespecified alternative hypothesis is measured to control both false positives and false negatives directly. The procedure was validated in the context of localizer tasks on simulated brain images and using a real data set of 100 runs per subject. Voxels categorized as active with ABT can be confidently included in the definition of the fROI, while inactive voxels can be confidently excluded. Additionally, the ABT method complements classic null hypothesis significance testing with valuable information by making a distinction between voxels that show evidence against both the null and alternative and voxels for which the alternative hypothesis cannot be rejected despite lack of evidence against the null
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Characterization of PolyJet additive manufacturing in support of model-based definition
The versatility, precision, and ability to create complex geometries afforded by Additive Manufacturing (AM) make it a valuable tool for product designers, engineers, and manufacturers. While AM offers several advantages, the lack of recognized product definition and design standards is a significant barrier to widespread adoption. Product definition practices like Model-Based Definition (MBD) make forming a standardized hub for information about an AM process easier.
PolyJet manufacturing, an AM process, has various materials and unique capabilities and would benefit significantly from MBD. To enable the use of MBD, Design for AM (DfAM) guidelines for PolyJet must be formed for communicating design intent and manufacturing requirements. Great strides have been made in forming DfAM guidelines for PolyJet. However, no comprehensive metrology studies have been done to characterize the multi-material printing capabilities unique to PolyJet.
Three metrology test parts are designed to characterize the PolyJet process and its post-processes. Parts #1 and #2 evaluate the performance of single-material vs. multi-material parts, feature resolution, and geometric accuracy. Test part #3 characterizes the survivability of features in the post-processing stage. All parts are evaluated across different feature sizes and build orientations for a robust understanding of the PolyJet process. The results are compiled into graphs, color-coded charts, and data analysis that guide future designers to avoid unnecessary re-design and part failure.Mechanical Engineerin
Variance decomposition for single-subject task-based fMRI activity estimates across many sessions
AbstractHere we report an exploratory within-subject variance decomposition analysis conducted on a task-based fMRI dataset with an unusually large number of repeated measures (i.e., 500 trials in each of three different subjects) distributed across 100 functional scans and 9 to 10 different sessions. Within-subject variance was segregated into four primary components: variance across-sessions, variance across-runs within a session, variance across-blocks within a run, and residual measurement/modeling error. Our results reveal inhomogeneous and distinct spatial distributions of these variance components across significantly active voxels in grey matter. Measurement error is dominant across the whole brain. Detailed evaluation of the remaining three components shows that across-session variance is the second largest contributor to total variance in occipital cortex, while across-runs variance is the second dominant source for the rest of the brain. Network-specific analysis revealed that across-block variance contributes more to total variance in higher-order cognitive networks than in somatosensory cortex. Moreover, in some higher-order cognitive networks across-block variance can exceed across-session variance. These results help us better understand the temporal (i.e., across blocks, runs and sessions) and spatial distributions (i.e., across different networks) of within-subject natural variability in estimates of task responses in fMRI. They also suggest that different brain regions will show different natural levels of test-retest reliability even in the absence of residual artifacts and sufficiently high contrast-to-noise measurements. Further confirmation with a larger sample of subjects and other tasks is necessary to ensure generality of these results
Salud, Ciencia y TecnologÃa (Health, Science and Technology): a space for scientific communication with an interdisciplinary approach
COVID-19, or severe acute respiratory syndrome type 2 coronavirus (SARS-CoV-2), is transmitted through large droplets generated during coughs and sneezes by symptomatic patients, but can also occur in asymptomatic individuals and before onset. of symptoms. Dental services are not unrelated to the COVID-19 pandemic. This article describes some considerations based on dental care in the context of the COVID-19 pandemic. In the scenario we live in today, a lot of uncertainty is generated in the decision-making process. We are aware that the extreme dynamics of the outbreak and the relative speed of information gathering can determine a sudden change of opinion and recommendations for the prevention of SAR-CoV-2 infection in the setting of dental care. Stomatology professionals are extremely exposed to the risk of SAR-CoV-2 infection, so it is necessary to take proactive and preventive measures as a pillar to contain the spread of the virus
Impact of goal directed therapy in head and neck oncological surgery with microsurgical reconstruction: free flap viability and complications
Background: Surgical outcomes in free flap reconstruction of head and neck defects in cancer patients have improved steadily in recent years; however, correct anaesthesia management is also important. The aim of this study has been to show whether goal directed therapy can improve flap viability and morbidity and mortality in surgical patients. Methods: we performed an observational case control study to analyse the impact of introducing a semi invasive device (Flo Trac®) during anaesthesia management to optimize fluid management. Patients were divided into two groups: one received goal directed therapy (GDT group) and the other conventional fluid management (CFM group). Our objective was to compare surgical outcomes, complications, fluid management, and length of stay between groups. Results: We recruited 140 patients. There were no differences between groups in terms of demographic data. Statistically significant differences were observed in colloid infusion (GDT 53.1% vs. CFM 74.1%, p = 0.023) and also in intraoperative and postoperative infusion of crystalloids (CFM 5.72 (4.2, 6.98) vs. GDT 3.04 (2.29, 4.11), p < 0.001), which reached statistical significance. Vasopressor infusion in the operating room (CFM 25.5% vs. GDT 74.5%, p < 0.001) and during the first postoperative 24h (CFM 40.6% vs. GDT 75%, p > 0.001) also differed. Differences were also found in length of stay in the intensive care unit (hours: CFM 58.5 (40, 110) vs. GDT 40.5 (36, 64.5), p = 0.005) and in the hospital (days: CFM 15.5 (12, 26) vs. GDT 12 (10, 19), p = 0.009). We found differences in free flap necrosis rate (CMF 37.1% vs. GDT 13.6%, p = 0.003). One-year survival did not differ between groups (CFM 95.6% vs. GDT 86.8%, p = 0.08). Conclusions: Goal directed therapy in oncological head and neck surgery improves outcomes in free flap reconstruction and also reduces length of stay in the hospital and intensive care unit, with their corresponding costs. It also appears to reduce morbidity, although these differences were not significant. Our results have shown that optimizing intraoperative fluid therapy improves postoperative morbidity and mortalit
Robust Ensemble Classification Methodology for I123-Ioflupane SPECT Images and Multiple Heterogeneous Biomarkers in the Diagnosis of Parkinson’s Disease
In last years, several approaches to develop an effective Computer-Aided-Diagnosis
(CAD) system for Parkinson’s Disease (PD) have been proposed. Most of these methods
have focused almost exclusively on brain images through the use of Machine-Learning
algorithms suitable to characterize structural or functional patterns. Those patterns
provide enough information about the status and/or the progression at intermediate
and advanced stages of Parkinson’s Disease. Nevertheless this information could be
insufficient at early stages of the pathology. The Parkinson’s ProgressionMarkers Initiative
(PPMI) database includes neurological images along with multiple biomedical tests.
This information opens up the possibility of comparing different biomarker classification
results. As data come from heterogeneous sources, it is expected that we could include
some of these biomarkers in order to obtain new information about the pathology. Based
on that idea, this work presents an Ensemble Classification model with Performance
Weighting. This proposal has been tested comparing Healthy Control subjects (HC)
vs. patients with PD (considering both PD and SWEDD labeled subjects as the same
class). This model combines several Support-Vector-Machine (SVM) with linear kernel
classifiers for different biomedical group of tests—including CerebroSpinal Fluid (CSF),
RNA, and Serum tests—and pre-processed neuroimages features (Voxels-As-Features
and a list of definedMorphological Features) fromPPMI database subjects. The proposed
methodology makes use of all data sources and selects the most discriminant features
(mainly from neuroimages). Using this performance-weighted ensemble classification
model, classification results up to 96% were obtained.This work was supported by the MINECO/FEDER under
the TEC2015-64718-R project and the Ministry of Economy,
Innovation, Science and Employment of the Junta de AndalucÃa
under the Excellence Project P11-TIC-7103
An Analysis of Research Trends and Knowledge Structure in the Field of Affordable and Clean Energy
INTRODUCTION: Energy is the foundation of all human endeavors and is intertwined with human progress. The access to sustainable energy services is a fundamental requirement for sustainable development, encompassing poverty eradication, food security, health, well-being, and education quality. Affordable and clean energy is explicitly recognized as one of the 17 sustainable development goals.
OBJECTIVE: to analyse research trends and the knowledge structure in the field of affordable and clean energy.
METHODS: This study was based on a descriptive bibliometric analysis of SDGs 7 "Affordable and Clean Energy". The Scopus database was used as a source of information, between 2012 and 2021.
RESULTS: The trend of documents on Affordable and Clean Energy reveals a steady increase in the number of published papers related to this topic, indicating a growing interest and activity in researching and disseminating information about sustainable energy. It is observed that international collaboration accounts for 21.8% of the analyzed documents, indicating a significant involvement of researchers from different countries. Engineering emerges as the leading subject area with 591,146 scholarly outputs, indicating a strong focus on technological advancements and innovation.
CONCLUSIONS: Scientific production in the field of affordable and clean energy has experienced steady growth, reflecting an increasing interest in research and development of sustainable energy solutions. However, it is important to recognize that this increase in the number of published papers has not translated into greater impact and recognition in the scientific community. Although more knowledge is being generated, its influence seems to be diminishing. Countries that participate in joint research obtain a higher number of citations, indicating the importance of establishing international linkages to maximize the visibility and impact of research
Tendencias, colaboración e impacto de la producción cientÃfica en Web of Science sobre cáncer bucal
Introduction: oncological diseases, including oral cancer, are the object of study of various institutions; for this reason it is necessary to analyze the behavior of this published science.Objective: to analyze the scientific production on oral cancer in the Web of Science in the period 2000 to 2020.Methods: a bibliometric study of the articles on oral cancer published in the Core Collections of Web of Science was conducted. The co-occurrence matrices for the analysis of the networks were pre-processed in Bibexel, and VOSviewer v1.6.15 was used its analysis. Visibility, impact and cooperation indicators were analyzed.Results: the documents analyzed (10349), where 76,50 % were original articles. The citations received were 198 302, for an average of 19, 9 citations per article. The variation rate in terms of the number of articles was 82,91 %. Publications written in English   language reached 98,96 %. The United States was the most productive country, with 23,92 %. The documents were published in 1416 resources and signed by 5160 institutions; at least 138 collaborated on one article.Conclusions: there is an increasing interest in research on oral cancer, concentrated in a small number of countries which exhibit genuine leadership capabilities in this field. Progress was evidenced in terms of international collaboration. The analysis of the co-occurrence of terms reflects the interest of the international scientific community in the prevention, diagnosis and treatment of this disease at a global level.Introducción: las enfermedades oncológicas, entre ellas el cáncer bucal, constituyen el objeto de estudio de diversas instituciones, de ahà que sea necesario analizar el comportamiento de esta ciencia publicada. Objetivo: analizar la producción cientÃfica sobre cáncer bucal en la Web of Science en el periodo 2000 a 2020.Métodos: se realizó un estudio bibliométrico de los artÃculos sobre cáncer bucal publicados en la Core Collections de la Web of Science. Las matrices de co-ocurrencia para el análisis de las redes fueron pre-procesados en Bibexel, y se empleó VOSviewer v1.6.15 para analizar. Se analizaron indicadores de visibilidad, impacto y cooperación.Resultados: se analizaron 10 349 documentos, donde el 76,50 % fueron originales. Se recibieron 198 302 citas, para un promedio de 19,99 citas por artÃculos. La tasa de variación en cuanto al número de artÃculos fue del 82,91 %. Las publicaciones redactadas en idioma inglés constituyeron el 98,96 %. Estados Unidos resultó el paÃs más productivo, con el 23,92 %. Los documentos se publicaron en 1 416 recursos y se firmaron por 5 160 instituciones, de ellas 138 colaboraron al menos en 1un artÃculo.Conclusiones: existe un interés creciente en la investigación sobre el cáncer bucal, concentrada en un pequeño número de paÃses, los que exhiben genuinas capacidades de liderazgo en este campo. Se evidenció un avance en cuanto a la colaboración internacional. El análisis de la co-ocurrencia de términos refleja el interés de la comunidad cientÃfica internacional en función de la prevención, diagnóstico y tratamiento de esta enfermedad a nivel global
Increased severity in SARS-CoV-2 infection of minorities in Spain
Introduction: With the global spread of COVID-19, studies in the US and UK have shown that certain communities have been strongly impacted by COVID-19 in terms of incidence and mortality. The objective of the study was to determine social determinants of health among COVID-19 patients hospitalized in the two major cities of Spain. Material and methods: A multicenter retrospective case series study was performed collecting administrative databases of all COVID-19 patients ≥18 years belonging to two centers in Madrid and two in Barcelona (Spain) collecting data from 1st March to 15th April 2020. Variables obtained age, gender, birthplace and residence ZIP code. From ZIP code we obtained per capita income of the area. Predictors of the outcomes were explored through generalized linear mixed-effects models, using center as random effect. Results: There were 5,235 patients included in the analysis. After multivariable analysis adjusted by age, sex, per capita income, population density, hospital experience, center and hospital saturation, patients born in Latin American countries were found to have an increase in ICU admission rates (OR 1.56 [1.13-2.15], p<0.01) but no differences were found in the same model regarding mortality (OR 1.35 [0.95-1.92], p=0.09). Conclusions: COVID-19 severity varies widely, not only depending on biological but also socio-economic factors. With the emerging evidence that this subset of population is at higher risk of poorer outcomes, targeted public health strategies and studies are needed
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