Publications by authors named "Tobon C"

Atrial fibrillation (AF) is the most common cardiac arrhythmia with mechanisms of initiation and sustaining that are not fully understood. The clinical procedure for AF contemplates the analysis of the atrial electrograms, whose morphology has been correlated with the underlying structure of the atrial myocardium. This study employs a mathematical model incorporating fractional calculus to simulate cardiac electrical conduction, accounting for tissue structural inhomogeneities using complex-valued orders.

View Article and Find Full Text PDF
Article Synopsis
  • * Traditional ablation methods may not fully utilize dynamic features in electrogram (EGM) signals, but using the fractional Fourier transform (FrFT) can help capture these time-varying aspects, improving the understanding of AF mechanisms and treatment strategies.
  • * A new FrFT-based algorithm enhances analysis of EGM signals from simulated AF, optimizing the representation of frequency changes, which helps identify areas of abnormal heart activity and can guide more effective ablation techniques.
View Article and Find Full Text PDF

Air pollution is associated with around 6.5 million premature deaths annually, which are directly related to cardiovascular diseases, and the most dangerous atmospheric pollutants to health are as follows: NO, SO, CO, and PM. The mechanisms underlying the observed effects have not yet been clearly defined.

View Article and Find Full Text PDF

Particle matter (PM) is a complex mixture of particles suspended in the air, mainly caused by fuel combustion from vehicles and industry, and has been related to pulmonary and cardiovascular diseases. The Metropolitan Area of Aburrá Valley in Colombia is the second most populous urban agglomeration in the country and the third densest in the world, composed of ten municipalities. Examining the physicochemical properties of PM is crucial in comprehending its composition and its effects on human health, as it varies based on the socioeconomic dynamics specific to each city.

View Article and Find Full Text PDF

Objective: To describe the main retinal alterations detected by non-mydriatic retinal camera screening and to evaluate factors related to referral to ophthalmology in a population at high cardiovascular risk in Palmira, Colombia.

Materials And Methods: Cross-sectional observational study, which included 11,983 photographic imaging records of patients with hypertension and diabetes mellitus from Gesencro's S.A.

View Article and Find Full Text PDF

Introduction: The Alzheimer's Prevention Initiative Autosomal-Dominant Alzheimer's Disease (API ADAD) Trial evaluated the anti-oligomeric amyloid beta (Aβ) antibody therapy crenezumab in cognitively unimpaired members of the Colombian presenilin 1 (PSEN1) E280A kindred. We report availability, methods employed to protect confidentiality and anonymity of participants, and process for requesting and accessing baseline data.

Methods: We developed mechanisms to share baseline data from the API ADAD Trial in consultation with experts and other groups sharing data from Alzheimer's disease (AD) prevention trials, balancing the need to protect anonymity and trial integrity with making data broadly available to accelerate progress in the field.

View Article and Find Full Text PDF
Article Synopsis
  • The study looked at how being male or female affects the risk and symptoms of Alzheimer's disease in people who carry a certain genetic mutation.
  • They analyzed data from 167 people with the mutation and 75 without it, all aged 30 to 53, using brain scans and memory tests.
  • The results showed that females had better memory than males, especially in recalling information, which suggests that women might be better at fighting off some effects of Alzheimer's compared to men.
View Article and Find Full Text PDF

Remodeling in atrial fibrillation (AF) underlines the electrical and structural changes in the atria, where fibrosis is a hallmark of arrhythmogenic structural alterations. Fibrosis is an important feature of the AF substrate and can lead to abnormal conduction and, consequently, mechanical dysfunction. The fibrotic process comprises the presence of fibrotic cells, including fibroblasts, myofibroblasts and fibrocytes, which play an important role during fibrillatory dynamics.

View Article and Find Full Text PDF

Particulate matter (PM) is considered the most severe environmental pollution problem due to its serious effects on human health associated with an increased risk of cardiovascular morbidity and mortality. In this work, a physicochemical characterization of PM10 from the city of Medellin was developed. The results evince that lead (Pb) is one of the most abundant elements since it is present in all analyzed samples.

View Article and Find Full Text PDF

Introduction: The API AutosomalDominant AD (ADAD) Colombia Trial is a placebo-controlled clinical trial of crenezumab in 252 cognitively unimpaired 30 to 60-year-old Presenilin 1 (PSEN1) E280A kindred members, including mutation carriers randomized to active treatment or placebo and non-carriers who receive placebo.

Methods: Of the 252 enrolled, we present data on a total of 242 mutation carriers and non-carriers matched by age range, excluding data on 10 participants to protect participant confidentiality, genetic status, and trial integrity.

Results: We summarize demographic, clinical, cognitive, and behavioral data from 167 mutation carriers and 75 non-carriers, 30 to 53 years of age.

View Article and Find Full Text PDF

In clinical practice, reducing the burden of persistent atrial fibrillation by pharmacological means is challenging. We explored if blocking the background and the acetylcholine-activated inward rectifier potassium currents (I and I) could be antiarrhythmic in persistent atrial fibrillation. We thus tested the hypothesis that blocking I and I with chloroquine decreases the burden of persistent atrial fibrillation.

View Article and Find Full Text PDF
Article Synopsis
  • The text discusses a new method for locating important areas on the atrial surface in patients with atrial fibrillation (AF) to help guide heart ablation procedures.
  • This method creates an electroanatomical map using complex electrogram (EGM) signals, which involves analyzing various features of these signals without predefined morphological classifications.
  • Initial testing shows promise in identifying critical AF sites and rotor pivot points through clustering, but more clinical research is necessary to confirm its effectiveness and understand its relationship with AF conditions.
View Article and Find Full Text PDF

Catheter ablation of critical electrical propagation sites is a promising tool for reducing the recurrence of atrial fibrillation (AF). The spatial identification of the arrhythmogenic mechanisms sustaining AF requires the evaluation of electrograms (EGMs) recorded over the atrial surface. This work aims to characterize functional reentries using measures of entropy to track and detect a reentry core.

View Article and Find Full Text PDF

A search for new heavy particles that decay into top-quark pairs is performed using data collected from proton-proton collisions at a centre-of-mass energy of 13  by the ATLAS detector at the Large Hadron Collider. The integrated luminosity of the data sample is 36.1 fb .

View Article and Find Full Text PDF

A search for new phenomena in final states containing an or pair, jets, and large missing transverse momentum is presented. This analysis makes use of proton-proton collision data with an integrated luminosity of , collected during 2015 and 2016 at a centre-of-mass energy with the ATLAS detector at the Large Hadron Collider. The search targets the pair production of supersymmetric coloured particles (squarks or gluinos) and their decays into final states containing an or pair and the lightest neutralino ( ) via one of two next-to-lightest neutralino ( ) decay mechanisms: , where the boson decays leptonically leading to a peak in the dilepton invariant mass distribution around the boson mass; and with no intermediate resonance, yielding a kinematic endpoint in the dilepton invariant mass spectrum.

View Article and Find Full Text PDF

The mechanisms of atrial fibrillation (AF) are a challenging research topic. The rotor hypothesis states that the AF is sustained by a reentrant wave that propagates around an unexcited core. Cardiac tissue heterogeneities, both structural and cellular, play an important role during fibrillatory dynamics, so that the ionic characteristics of the currents, their spatial distribution and their structural heterogeneity determine the meandering of the rotor.

View Article and Find Full Text PDF

Introduction: Autosomal-dominant Alzheimer's disease (ADAD) represents a crucial population for identifying prevention strategies that might modify disease course for cognitively unimpaired individuals at high imminent risk for developing symptoms due to Alzheimer's disease (AD), that is, who have "preclinical" AD. Crenezumab is an antiamyloid monoclonal antibody that binds monomeric and aggregated forms of amyloid β, with highest affinity for oligomers; it is in development for early stages of sporadic AD and for ADAD.

Methods: This is a prospective, randomized, double-blind, placebo-controlled phase 2 study of the efficacy of crenezumab versus placebo in asymptomatic E280A mutation carriers from family kindreds with ADAD in Colombia.

View Article and Find Full Text PDF
Article Synopsis
  • The internal conflict in Colombia has significant implications for both civilians and ex-combatants, with studies indicating that ex-combatants often exhibit traits of antisocial personality disorder (ASPD).
  • Quantitative EEG (qEEG) was used to compare brain activity patterns between ex-combatants and a control group, while psychopathy and other mental disorders were assessed using established psychological tools.
  • Findings revealed notable differences in psychopathy levels and specific brain wave patterns (alpha-2 and beta waves) between groups, suggesting a link between these brain activities and traits associated with ASPD.
View Article and Find Full Text PDF

The Alzheimer's Prevention Initiative (API) Autosomal Dominant Alzheimer's Disease (ADAD) trial evaluates the anti-amyloid-β antibody crenezumab in cognitively unimpaired persons who, based on genetic background and age, are at high imminent risk of clinical progression, and provides a powerful test of the amyloid hypothesis. The Neurosciences Group of Antioquia implemented a pre-screening process with the goals of decreasing screen failures and identifying participants most likely to adhere to trial requirements of the API ADAD trial in cognitively unimpaired members of Presenilin1 E280A mutation kindreds. The pre-screening failure rate was 48.

View Article and Find Full Text PDF

This paper presents a direct measurement of the decay width of the top quark using events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb .

View Article and Find Full Text PDF

A measurement of and production is presented. It is based on a data sample from Pb+Pb collisions at and collisions at recorded by the ATLAS detector at the LHC in 2015, corresponding to an integrated luminosity of and in Pb+Pb and , respectively. The measurements of per-event yields, nuclear modification factors, and non-prompt fractions are performed in the dimuon decay channel for GeV in dimuon transverse momentum, and in rapidity.

View Article and Find Full Text PDF
Article Synopsis
  • PBDEs were previously used as flame retardants in household products until they were phased out, and new chemicals like TBB and TBPH have taken their place.
  • A study measured the levels of PBDEs, TBB, and TBPH in dust and handwipes from mothers and children in New York City, finding widespread presence in both samples.
  • The results showed that children had higher concentrations of these flame retardants on their handwipes compared to their mothers, indicating significant exposure to these chemicals in their environment.
View Article and Find Full Text PDF