Non-invasive Spatial Mapping of Frequencies in Atrial Fibrillation: Correlation With Contact Mapping

Introduction: Regional differences in activation rates may contribute to the electrical substrates that maintain atrial fibrillation (AF), and estimating them non-invasively may help guide ablation or select anti-arrhythmic medications. We tested whether non-invasive assessment of regional AF rate accurately represents intracardiac recordings. Methods: In 47 patients with AF (27 persistent, age 63 ± 13 years) we performed 57-lead non-invasive Electrocardiographic Imaging (ECGI) in AF, simultaneously with 64-pole intracardiac signals of both atria. ECGI was reconstructed by Tikhonov regularization. We constructed personalized 3D AF rate distribution maps by Dominant Frequency (DF) analysis from intracardiac and non-invasive recordings. Results: Raw intracardiac and non-invasive DF differed substantially, by 0.54 Hz [0.13 - 1.37] across bi-atrial regions (R2 = 0.11). Filtering by high spectral organization reduced this difference to 0.10 Hz (cycle length difference of 1 - 11 ms) [0.03 - 0.42] for patient-level comparisons (R2 = 0.62), and 0.19 Hz [0.03 - 0.59] and 0.20 Hz [0.04 - 0.61] for median and highest DF, respectively. Non-invasive and highest DF predicted acute ablation success (p = 0.04). Conclusion: Non-invasive estimation of atrial activation rates is feasible and, when filtered by high spectral organization, provide a moderate estimate of intracardiac recording rates in AF. Non-invasive technology could be an effective tool to identify patients who may respond to AF ablation for personalized therapy

Relating Electron Donor and Carboxylic Acid Anchoring Substitution Effects in Azo Dyes to Dye-Sensitized Solar Cell Performance

The relationship between the molecular structures of a series of azo dyes and their operational performance when applied to dye-sensitized solar cells (DSSCs) is probed via experimental and computational analysis. Seven azo dyes, with three different donating groups (dimethylamino, diethylamino, and dipropylamino) and carboxylic acid anchoring positions (<i>ortho</i>-, <i>meta</i>-, and <i>para</i>-substituted phenyl rings) are studied. Single-crystal X-ray diffraction is employed in order to analyze the effects of conformation and quantify the contribution of quinoidal resonance forms to the intramolecular charge transfer (ICT), which controls their intrinsic photovoltaic potential from an electronic standpoint. Harmonic oscillator stabilization energy (HOSE) calculations indicate that the <i>para</i>- and <i>ortho</i>-azo dyes exhibit potential for DSSC application. However, from a geometrical standpoint, the crystal structure data, proton nuclear magnetic resonance spectroscopy (¹H NMR), and density functional theory (DFT) all indicate that intramolecular hydrogen bonds form in <i>ortho</i>-dyes within both solid and solution states, impeding their intrinsic ICT-based photovoltaic potential, and offering insights into the photostability of azo dyes and the dye···TiO₂ anchoring mechanism in DSSCs. Donor effects are manifested in the packing mode and molecular planarity revealed by X-ray crystallography and in the UV/vis absorption spectra. DFT and time-dependent density functional theory (TDDFT) were performed to understand the electronic and optical properties of these azo dyes; these calculations compare well with experimental findings. Operational tests of DSSCs, functionalized by these azo dyes, show that the carboxylic acid anchoring position plays a crucial role in DSSC performance, while donating groups offer a much less obvious effect on the overall DSSC device efficiency

Relating Electron Donor and Carboxylic Acid Anchoring Substitution Effects in Azo Dyes to Dye-Sensitized Solar Cell Performance

The relationship between the molecular structures of a series of azo dyes and their operational performance when applied to dye-sensitized solar cells (DSSCs) is probed via experimental and computational analysis. Seven azo dyes, with three different donating groups (dimethylamino, diethylamino, and dipropylamino) and carboxylic acid anchoring positions (<i>ortho</i>-, <i>meta</i>-, and <i>para</i>-substituted phenyl rings) are studied. Single-crystal X-ray diffraction is employed in order to analyze the effects of conformation and quantify the contribution of quinoidal resonance forms to the intramolecular charge transfer (ICT), which controls their intrinsic photovoltaic potential from an electronic standpoint. Harmonic oscillator stabilization energy (HOSE) calculations indicate that the <i>para</i>- and <i>ortho</i>-azo dyes exhibit potential for DSSC application. However, from a geometrical standpoint, the crystal structure data, proton nuclear magnetic resonance spectroscopy (¹H NMR), and density functional theory (DFT) all indicate that intramolecular hydrogen bonds form in <i>ortho</i>-dyes within both solid and solution states, impeding their intrinsic ICT-based photovoltaic potential, and offering insights into the photostability of azo dyes and the dye···TiO₂ anchoring mechanism in DSSCs. Donor effects are manifested in the packing mode and molecular planarity revealed by X-ray crystallography and in the UV/vis absorption spectra. DFT and time-dependent density functional theory (TDDFT) were performed to understand the electronic and optical properties of these azo dyes; these calculations compare well with experimental findings. Operational tests of DSSCs, functionalized by these azo dyes, show that the carboxylic acid anchoring position plays a crucial role in DSSC performance, while donating groups offer a much less obvious effect on the overall DSSC device efficiency

Radial glia promote microglial development through integrin α V β 8 -TGFβ1 signaling

Summary Microglia diversity emerges from interactions between intrinsic genetic programs and environment-derived signals, but how these processes unfold and interact in the developing brain remains unclear. Here, we show that radial glia-expressed integrin beta 8 (ITGB8) expressed in radial glia progenitors activates microglia-expressed TGFβ1, permitting microglial development. Domain-restricted deletion of Itgb8 in these progenitors establishes complementary regions with developmentally arrested “dysmature” microglia that persist into adulthood. In the absence of autocrine TGFβ1 signaling, we find that microglia adopt a similar dysmature phenotype, leading to neuromotor symptoms almost identical to Itgb8 mutant mice. In contrast, microglia lacking the TGFβ signal transducers Smad2 and Smad3 have a less polarized dysmature phenotype and correspondingly less severe neuromotor dysfunction. Finally, we show that non-canonical (Smad-independent) signaling partially suppresses disease and development associated gene expression, providing compelling evidence for the adoption of microglial developmental signaling pathways in the context of injury or disease

A clinical prediction rule for classifying patients with low back pain who demonstrate short-term improvement with mechanical lumbar traction

The objective of the study was to develop a clinical prediction rule for identifying patients with low back pain, who improved with mechanical lumbar traction. A prospective, cohort study was conducted in a physiotherapy clinic at a local hospital. Patients with low back pain, referred to physiotherapy were included in the study. The intervention was a standardized mechanical lumbar traction program, which comprised three sessions provided within 9 days. Patient demographic information, standard physical examination, numeric pain scale, fear-avoidance beliefs questionnaire and Oswestry low back pain disability index (pre- and post-intervention) were recorded. A total of 129 patients participated in the study and 25 had positive response to the mechanical lumbar traction. A clinical prediction rule with four variables (non-involvement of manual work, low level fear-avoidance beliefs, no neurological deficit and age above 30 years) was identified. The presence of all four variables (positive likelihood ratio = 9.36) increased the probability of response rate with mechanical lumbar traction from 19.4 to 69.2%. It appears that patients with low back pain who were likely to respond to mechanical lumbar traction may be identified