796 research outputs found
A poroelastic model coupled to a fluid network with applications in lung modelling
Here we develop a lung ventilation model, based a continuum poroelastic
representation of lung parenchyma and a 0D airway tree flow model. For the
poroelastic approximation we design and implement a lowest order stabilised
finite element method. This component is strongly coupled to the 0D airway tree
model. The framework is applied to a realistic lung anatomical model derived
from computed tomography data and an artificially generated airway tree to
model the conducting airway region. Numerical simulations produce
physiologically realistic solutions, and demonstrate the effect of airway
constriction and reduced tissue elasticity on ventilation, tissue stress and
alveolar pressure distribution. The key advantage of the model is the ability
to provide insight into the mutual dependence between ventilation and
deformation. This is essential when studying lung diseases, such as chronic
obstructive pulmonary disease and pulmonary fibrosis. Thus the model can be
used to form a better understanding of integrated lung mechanics in both the
healthy and diseased states
Detection and Analysis of Gasoline Residues on Household Samples by Using Gas Chromatography
Arson is an easy to commit crime. The required supplies are easily and cheaply available to the general public and no special knowledge such as hacking and marksmanship is required. It is also effective, as fires can quickly cause huge monetary damages and loss of life. Arson can be problematic to forensic investigators, as the nature of flames can destroy evidence such as fingerprints and hair at the scene of the crime. In nearly all cases of arson a liquid accelerant is used. Liquid accelerants, such as gasoline, speed up the process and increase the damage done during the time.
Our research focuses on the detection of gasoline residues on different household samples over various intervals of time. For this goal, regular unleaded regular gasoline (87 octane number) and four common household materials: carpet, plywood, newspaper, and cotton fabric were chosen. These household samples were cut into the same size pieces (1.5 x 1.5 cm2). 50 µL of gasoline was splashed on them, and they were dried at room temperature for various time intervals (10 min, 30 min, 1 h, 2 h, 4 h, 6 h, 12 h, 24 h, and 48 h) prior to chemical analysis. Detection of gasoline residues from these samples were conducted via gas chromatography with headspace sampling and flame ionization detector. Our preliminary data has shown that a trace amount of gasoline was identified from a cotton fabric sample even after 48 hours of staying at room temperature.
Key Words: arson, gas chromatography, chemistry, gasoline, forensic scienc
Nexo agua-energÃa: desde el nacimiento del rÃo Llobregat hasta Manresa
En este trabajo se estudia el nexo agua-energÃa en el tramo del rÃo Llobregat desde Castellar de N’hug hasta Manresa. Se lleva a cabo una evaluación de la cantidad de energÃa necesaria en las estaciones potabilizadoras y depuradoras para adecuar el agua del rÃo, además de determinar la cantidad de energÃa que generan las centrales mini-hidroeléctricas. Estos dos valores de energÃa finales son comparados para demostrar si se consume más energÃa que la que se genera, o al contrario.
Se estudia la necesidad de agua para la producción de energÃa a partir de las centrales mini-hidroeléctricas, es decir, aquellas centrales que tienen una potencia instalada de entre 100 i 1.000 kW ya que son las que mayoritariamente, encontramos en este tramo del rÃo. Asà mismo, también se estudia la necesidad o consumo de energÃa para la depuración y el acondicionamiento del agua, teniendo como base los procesos de depuración y potabilización del agua.
Para ello, se analizan las tendencias de consumos energéticos de las EDAR, asà como de las ETAP y se intenta encontrar una relación entre el caudal de agua tratado y el consumo energético en ambos casos.
Además, a partir del ratio con unidades kWh/m3 (cantidad de energÃa producida o consumida por unidad de volumen de agua), se puede conocer por un lado, si las EDAR y las ETAP tienen mayor o menor consumo por unidad de agua tratada y por otro lado, si las mini-hidroeléctricas necesitan más o menos cantidad de agua para producir energÃa
Superación personal en adolescentes desde la educabilidad y la enseñabilidad en escenarios pedagógicos rurales.
This article deals with the subject of self-overcoming in adolescents from the processes of education and teaching, designing and applying strategies for their promotion in a specific rural context of the municipality of Monteria, Córdoba. The socio-economic, cultural and educational characteristics of the family and school environment were taken into account, identifying and analyzing conceptions, practices, meanings and expectations of the student’s educational and training process.The research was qualitative, type action- participation; working with techniques such as the interview, participant observation, documentary review and discussion workshops, applied to students, teachers and parents. This allowed obtaining information for discussion, analysis and reflection of the educational process as a praxis. As a result, the article presents the analysis and reflection of the issue from the process of construction of self-overcoming actions through active and participatory classroom activities; its application within the educational process at the school and into the family environment and its evaluation. En este artÃculo se aborda la temática de la superación personal en adolescentes desde los procesos de educabilidad y enseñabilidad, diseñando y aplicando estrategias para su fomento en un contexto rural especÃfico del municipio de MonterÃa, Córdoba. Se tuvieron en cuenta las caracterÃsticas socioeconómicas, culturales y educativas del entorno familiar y escolar, identificando y analizando concepciones, prácticas, significados y expectativas del proceso educativo y formativo del estudiante.Investigación de corte cualitativo, tipo investigación acción participación, utilizando como técnicas la entrevista, observación participante, revisión documental y talleres de discusión, aplicadas a estudiantes, docentes y padres de familia que permitieron obtener información para la discusión, análisis y reflexión del proceso educativo desde su quehacer. Como resultados presenta el análisis y reflexión de la problemática desde el proceso de construcción de acciones generadoras de superación personal a partir de actividades de aula, activas y participativas, su aplicación en el proceso educativo desde el ámbito escolar y familiar, y su evaluación, respondiendo a los propósitos de la investigación
Investigating the prevalence of reactive online searching in the COVID-19 pandemic
Background:
The ongoing coronavirus disease (COVID-19) pandemic has placed an unprecedented strain on global society, healthcare, governments and mass media. Public dissemination of government policies, medical interventions and misinformation has been remarkably rapid and largely unregulated during the COVID-19 pandemic, resulting in increased misinterpretations, miscommunication, and public panic. Being the first full-scale global pandemic of the digital age, COVID-19 has presented novel challenges pertinent to government advice, the spread of news and misinformation, and the trade-off between the accessibility of science and the premature public use of unproven medical interventions.
Objective:
This study aims to assess the use of internet search terms relating to COVID-19 information and misinformation during the global pandemic, identify which were most used in six affected countries, investigate any temporal trends and the likely propagators of key search terms, and determine any correlation between the per capita cases and deaths with the adoption of these search terms in each of the six countries.
Methods:
This study uses relative search volume data extracted from Google Trends for search terms linked to the COVID-19 pandemic alongside per capita case and mortality data extracted from the European Open Data Portal, to identify the temporal dynamics of the spread of news and misinformation during the global pandemic in six affected countries (Australia, Germany, Italy, Spain, United Kingdom, United States of America). A correlation analysis was carried out to ascertain any correlation between the temporal trends of search term use and the rise of per capita mortality and disease cases.
Results:
Of the selected search terms, most were searched immediately following promotion by governments, public figures or viral circulation of unfounded claims, but also relating to the publication of scientific resources, which were sometimes misinterpreted before further dissemination. Strong correlations were identified between the volume of these COVID-19-related search terms, and per capita mortality and cases.
Conclusions:
These findings illustrate the increased rate and volume of public consumption of novel information during a global healthcare crisis. The strong positive correlation between mortality and online searching, particularly in countries with lower COVID-19 testing rates, may demonstrate the imperative to safeguard official communications and dispel misinformation in these countries. Online news, government briefings and social media provide a powerful tool for the dissemination of important information to the public during pandemics, but their misuse, and the presentation of misrepresented medical information, should be monitored, minimised and addressed to safeguard public safety. Ultimately, governments, public health authorities and scientists have a moral imperative to safeguard the truth and maintain an accessible discourse with the public to inhibit fear
Fuzzy Segmentation of the Left Ventricle in Cardiac MRI Using Physiological Constraints
We describe a general framework for adapting existing segmentation algorithms, such that the need for optimisation of intrinsic, potentially unintuitive parameters is minimized, focusing instead on applying intuitive physiological constraints. This allows clinicians to easily influence existing tools of their choice towards outcomes with physiological properties that are more relevant to their particular clinical contexts, without having to deal with the optimisation specifics of a particular algorithm’s intrinsic parameters. This is achieved by a structured exploration of the parameter space resulting in a subspace of relevant segmentations, and by subsequent fusion biased towards segmentations that best adhere to the imposed constraints. We demonstrate this technique on an algorithm used by a validated, and freely available cardiac segmentation suite (Segment – http://segment.heiberg.se)
Adipose tissue glycogen accumulation is associated with obesity-linked inflammation in humans
Objective: glycogen metabolism has emerged as a mediator in the control of energy homeostasis and studies in murine models reveal that adipose tissue might contain glycogen stores. Here we investigated the physio(patho)logical role of glycogen in human adipose tissue in the context of obesity and insulin resistance. Methods: we studied glucose metabolic flux of hypoxic human adipoctyes by nuclear magnetic resonance and mass spectrometry-based metabolic approaches. Glycogen synthesis and glycogen content in response to hypoxia was analyzed in human adipocytes and macrophages. To explore the metabolic effects of enforced glycogen deposition in adipocytes and macrophages, we overexpressed PTG, the only glycogen-associated regulatory subunit (PP1-GTS) reported in murine adipocytes. Adipose tissue gene expression analysis was performed on wild type and homozygous PTG KO male mice. Finally, glycogen metabolism gene expression and glycogen accumulation was analyzed in adipose tissue, mature adipocytes and resident macrophages from lean and obese subjects with different degrees of insulin resistance in 2 independent cohorts. Results: we show that hypoxia modulates glucose metabolic flux in human adipocytes and macrophages and promotes glycogenesis. Enforced glycogen deposition by overexpression of PTG re-orients adipocyte secretion to a pro-inflammatory response linked to insulin resistance and monocyte/lymphocyte migration. Furthermore, glycogen accumulation is associated with inhibition of mTORC1 signaling and increased basal autophagy flux, correlating with greater leptin release in glycogen-loaded adipocytes. PTG-KO mice have reduced expression of key inflammatory genes in adipose tissue and PTG overexpression in M0 macrophages induces a pro-inflammatory and glycolytic M1 phenotype. Increased glycogen synthase expression correlates with glycogen deposition in subcutaneous adipose tissue of obese patients. Glycogen content in subcutaneous mature adipocytes is associated with BMI and leptin expression. Conclusion: our data establish glycogen mishandling in adipose tissue as a potential key feature of inflammatory-related metabolic stress in human obesity
Detrimental effect of zwitterionic buffers on lysosomal homeostasis in cell lines and iPSC-derived neurons
Good’s buffers are commonly used for cell culture and, although developed to have minimal to no biological impact, they cause alterations in cellular processes such as autophagy and lysosomal enzyme activity. Using Chinese hamster ovary cells and induced pluripotent stem cell-derived neurons, this study explores the effect of zwitterionic buffers, specifically HEPES, on lysosomal volume and Ca2+ levels. Certain zwitterionic buffers lead to lysosomal expansion and reduced lysosomal Ca2+. Care should be taken when selecting buffers for growth media to avoid detrimental impacts on lysosomal function
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