Model of unidirectional block formation leading to reentrant ventricular tachycardia in the infarct border zone of postinfarction canine hearts

AbstractBackgroundWhen the infarct border zone is stimulated prematurely, a unidirectional block line (UBL) can form and lead to double-loop (figure-of-eight) reentrant ventricular tachycardia (VT) with a central isthmus. The isthmus is composed of an entrance, center, and exit. It was hypothesized that for certain stimulus site locations and coupling intervals, the UBL would coincide with the isthmus entrance boundary, where infarct border zone thickness changes from thin-to-thick in the travel direction of the premature stimulus wavefront.MethodA quantitative model was developed to describe how thin-to-thick changes in the border zone result in critically convex wavefront curvature leading to conduction block, which is dependent upon coupling interval. The model was tested in 12 retrospectively analyzed postinfarction canine experiments. Electrical activation was mapped for premature stimulation and for the first reentrant VT cycle. The relationship of functional conduction block forming during premature stimulation to functional block during reentrant VT was quantified.ResultsFor an appropriately placed stimulus, in accord with model predictions: 1. The UBL and reentrant VT isthmus lateral boundaries overlapped (error: 4.8±5.7mm). 2. The UBL leading edge coincided with the distal isthmus where the center-entrance boundary would be expected to occur. 3. The mean coupling interval was 164.6±11.0ms during premature stimulation and 190.7±20.4ms during the first reentrant VT cycle, in accord with model calculations, which resulted in critically convex wavefront curvature and functional conduction block, respectively, at the location of the isthmus entrance boundary and at the lateral isthmus edges.DiscussionReentrant VT onset following premature stimulation can be explained by the presence of critically convex wavefront curvature and unidirectional block at the isthmus entrance boundary when the premature stimulation interval is sufficiently short. The double-loop reentrant circuit pattern is a consequence of wavefront bifurcation around this UBL followed by coalescence, and then impulse propagation through the isthmus. The wavefront is blocked from propagating laterally away from the isthmus by sharp increases in border zone thickness, which results in critically convex wavefront curvature at VT cycle lengths

Assessment of Portuguese fitness centers: bridging the knowledge gap on harmful microbial contamination with focus on fungi

This research was funded by the Polish Minister of Science and Higher Education, under the program "Regional Initiative of Excellence" in 2019 - 2022 (Grant No. 008/RID/2018/19), by Instituto Politécnico de Lisboa, Lisbon, Portugal for funding the Projects IPL/2023/FoodAIIEU_ESTeSL; IPL/2023/ASPRisk_ESTeSL; IPL/2023/ARAFSawmills_ESTeSL. H&TRC and by FCT – Fundação para a Ciência e a Tecnologia, I.P. (Portugal) for funding the EEA Grants Project “Microbiological contamination in cultural heritage settings: shared experiences for better approaches - FBR_OC2_66”. The authors gratefully acknowledge the FCT/MCTES national support through the UIDB/05608/2020, UIDP/05608/2020, and the Ph.D. Grant UI/BD/151431/2021. This work was also supported by national funds through FCT/MCTES/FSE/UE, UI/BD/153746/2022, and CE3C unit UIDB/00329/2020 within the scope of a PhD Grant. We thank the fitness centers and workers for participating in the study. The work was supported by national funds through FCT/MCTES (PIDDAC) as the following: LEPABE (DOI: 10.54499/UIDB/00511/2020; DOI: 10.54499/UIDP/00511/2020); ALiCE (DOI: 10.54499/LA/P/0045/2020); REQUIMTE (DOI: 10.54499/UIDB/50006/2020; DOI: 10.54499/UIDP/50006/2020; DOI: 10.54499/ LA/P/0008/2020) from the Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES). Additional funding was provided by PCIF/SSO/0017/2018 FCT through national funds. Cátia Peixoto would like to acknowledge FCT for her fellowship SFRH/BD/147185/2019.The lack of knowledge regarding the extent of microbial contamination in Portuguese fitness centers (FC) puts attendees and athletes at risk for bioaerosol exposure. This study intends to characterize microbial contamination in Portuguese FC by passive sampling methods: electrostatic dust collectors (EDC) (N=39), settled dust (N=8), vacuum filters (N=8), and used cleaning mops (N=12). The obtained extracts were plated in selective culture media for fungi and bacteria. Filters, EDC, and mop sample extracts were also screened for antifungal resistance and used for the molecular detection of the selected Aspergillus sections. The detection of mycotoxins was conducted using a high-performance liquid chromatograph (HPLC) system and to determine the cytotoxicity of microbial contaminants recovered by passive sampling, HepG2 (human liver carcinoma) and A549 (human alveolar epithelial) cells were employed. The results reinforce the use of passive sampling methods to identify the most critical areas and identify environmental factors that influence microbial contamination, namely having a swimming pool. The cardio fitness area presented the highest median value of total bacteria (TSA: 9.69x102 CFU.m-2.day-1) and Gram-negative bacteria (VRBA: 1.23 CFU.m-2.day-1), while for fungi it was the open space area, with 1.86x101 CFU.m-2.day-1. Aspergillus sp. was present in EDC and in filters used to collect settled dust. Reduced azole susceptibility was observed in filters, EDC (on ICZ and VCZ), and mops (on ICZ). Fumonisin B2 was the only mycotoxin detected and was present in all sampling matrixes except settled dust. High and moderate cytotoxicity was obtained, suggesting that A549 cells were more sensitive to samples’ contaminants. The observed widespread of critical toxigenic fungal species with clinical relevance, such as Aspergillus section Fumigati, as well as Fumonisin B2 emphasizes the importance of frequent and effective cleaning procedures while using shared mops appeared as a vehicle of cross-contamination.info:eu-repo/semantics/publishedVersio

Avaliação da qualidade vocal de crianças sem queixas vocais: estudo prospectivo duplo-cego

OBJECTIVE: To evaluate the vocal quality of children without voice disorders, analyzing the possible presence and type of lesion, glottic coaptation and laryngeal constriction, roughness and breathiness vocal quality.MATERIALS AND METHODS: We evaluated 50 male children, aged 3 to 10, randomly selected, who did not present otorhinolaryngological disorders. All children went through an otorhinolaryngological exam, followed by videofibrolaryngoscopy and speech pathology evaluation.RESULTS: Out of the 50 children, 25 were classified as normal. Eight presented with cysts, and 17 had vocal nodules. We observed that normal vocal quality was significant in the normal group, while roughness and breathness were associated with the pathological group. We did not find a significant difference in vocal quality when we analyzed glottic coaptation and laryngeal constriction.CONCLUSIONS: Roughness and breathness were significantly associated with structural lesions of the vocal fold, while a normal vocal quality was associated with absence of structural lesions. The authors concluded that all signs of roughness or breathness should be considered in order to allow an early diagnosis of laryngeal alterations and, consequently, early treatment.OBJETIVO: Avaliar a qualidade vocal de crianças que não apresentam queixas de distúrbios na voz. As crianças foram analisadas quanto à possível presença e tipo delesão, quanto ao tipo de coaptação das pregas vocais, e quanto à rouquidão, aspereza e soprosidade da voz.MATERIAIS E MÉTODOS: Foram avalidas 50 crianças do sexo masculino, escolhidas aleatoriamente, na faixa etária de 3 a 10 anos, que não apresentavam queixasotorrinolaringológicas. To das as crianças passaram por exame otorrinolaringológico, seguido de videofibrolaringoscopia e avaliação fonoaudiolóigica.RESULTADOS: Das 50 crianças, 25 foram classificadas como normais. Oito eram portadoras de cisto e 17, portadoras de nódulo vocal, todas sem queixas vocais.Observamos que a qualidade vocal normal esteve presente de maneira significativa no grupo normal, enquanto a rouquidão e a soprosidade estiveram associadas de maneira significativa ao grupo patológico. Nós não observamos diferença significativaquanto a qualidade vocal ao analisarmos a coaptação glótica e a constrição laríngea.CONCLUSÕES: A qualidade vocal do tipo rouca e soprosa está associada de maneira significativa às com lesão estrutural das pregas vocais e a qualidade vocal normal, às crianças sem lesão estrutural. Assim, deve-se atentar para a presença de rouquidão em crianças de forma a permitir o diagnóstico precoce de alterações laríngeas e, conseqüentemente, a terapêutica

Nonperturbative transverse-momentum-dependent effects in dihadron and direct photon-hadron angular correlations in p+p collisions at s =200 GeV

Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at s=200 GeV. The correlations are sensitive to nonperturbative initial-state and final-state transverse momenta kT and jT in the azimuthal nearly back-to-back region Δφ∼π. To have sensitivity to small transverse momentum scales, nonperturbative momentum widths of pout, the out-of-plane transverse-momentum component perpendicular to the trigger particle, are measured. In this region, the evolution of pout can be studied when several different hard scales are measured. These widths are used to investigate possible effects from transverse-momentum-dependent factorization breaking. When accounting for the longitudinal-momentum fraction of the away-side hadron with respect to the near-side trigger particle, the widths are found to increase with the hard scale; this is qualitatively similar to the observed behavior in Drell-Yan and semi-inclusive deep-inelastic scattering interactions, where factorization is predicted to hold. The momentum widths are also studied as a function of center-of-mass energy by comparing to previous measurements at s=510 GeV. The nonperturbative jet widths also appear to increase with s at a similar xT, which is qualitatively consistent to similar measurements in Drell-Yan interactions. Future detailed global comparisons between measurements of processes where transverse-momentum-dependent factorization is predicted to hold and be broken will provide further insight into the role of color in hadronic interactions

Nonperturbative-transverse-momentum broadening in dihadron angular correlations in sNN =200 GeV proton-nucleus collisions

The PHENIX collaboration has measured high-pT dihadron correlations in p+p, p+Al, and p+Au collisions at sNN=200 GeV. The correlations arise from inter- and intrajet correlations and thus have sensitivity to nonperturbative effects in both the initial and final states. The distributions of pout, the transverse-momentum component of the associated hadron perpendicular to the trigger hadron, are sensitive to initial- and final-state transverse momenta. These distributions are measured multidifferentially as a function of xE, the longitudinal momentum fraction of the associated hadron with respect to the trigger hadron. The near-side pout widths, sensitive to fragmentation transverse momentum, show no significant broadening between p+Au, p+Al, and p+p. The away-side nonperturbative pout widths are found to be broadened in p+Au when compared to p+p; however, there is no significant broadening in p+Al compared to p+p collisions. The data also suggest that the away-side pout broadening is a function of Ncoll, the number of binary nucleon-nucleon collisions, in the interaction. The potential implications of these results with regard to initial- and final-state transverse-momentum broadening and energy loss of partons in a nucleus, among other nuclear effects, are discussed

Pseudorapidity Dependence of Particle Production and Elliptic Flow in Asymmetric Nuclear Collisions of p+Al, p+Au, d+Au, and ^{3}He+Au at sqrt[s_{NN}]=200 GeV.

Asymmetric nuclear collisions of p+Al, p+Au, d+Au, and ^{3}He+Au at sqrt[s_{NN}]=200  GeV provide an excellent laboratory for understanding particle production, as well as exploring interactions among these particles after their initial creation in the collision. We present measurements of charged hadron production dN_{ch}/dη in all such collision systems over a broad pseudorapidity range and as a function of collision multiplicity. A simple wounded quark model is remarkably successful at describing the full data set. We also measure the elliptic flow v_{2} over a similarly broad pseudorapidity range. These measurements provide key constraints on models of particle emission and their translation into flow

Measurements of μμ pairs from open heavy flavor and Drell-Yan in p+p collisions at s =200 GeV

PHENIX reports differential cross sections of μμ pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in p+p collisions at s=200 GeV at forward and backward rapidity (1.2<|η|<2.2). The μμ pairs from cc, bb, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and pT. The azimuthal opening angle correlation between the muons from cc and bb decays and the pair-pT distributions are compared to distributions generated using pythia and powheg models, which both include next-to-leading order processes. The measured distributions for pairs from cc are consistent with pythia calculations. The cc data present narrower azimuthal correlations and softer pT distributions compared to distributions generated from powheg. The bb data are well described by both models. The extrapolated total cross section for bottom production is 3.75±0.24(stat)±0.500.35(syst)±0.45(global) [μb], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy and is approximately a factor of 2 higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations