High density mapping guided partial antral ablation for a pulmonary vein isolation

The muscular discontinuities at the pulmonary vein (PV)–left atrial (LA) junction are known. The high-density mapping may help to find the muscular discontinuity. This study evaluated the efficacy of a partial antral ablation for a pulmonary vein (PV) isolation using high density (HD) mapping. A total of 60 drug-refractory atrial fibrillation (AF) patients undergoing catheter ablation were enrolled. The detailed activation mapping of each PV and LA junction was performed using an HD mapping system, and each PV segment’s activation pattern was classified into a “directly-activated from the LA” or “passively-activated from an adjacent PV segment” pattern. The antral ablations were performed at the directly-activated PV segments only when the PV had “passively-activated segments”. If the PV did not contain passively-activated segments, a circumferential antral ablation was performed on those PVs. A “successful partial antral ablation” was designated if the electrical isolation of targeted PV was achieved by ablation at the directly-activated segments only. If the isolation was not achieved even though all directly-activated segments were ablated, a “failed partial antral ablation” was designated, and then a circumferential ablation was performed. Among 240 PVs, passively-activated segments were observed in 140 (58.3%) PVs. Both inferior PVs had more passively-activated segments than superior PVs, and the posteroinferior segments had the highest proportion of passive activation. The overall rate of successful partial antral ablation was 85%. The atrial tachyarrhythmia recurrence was observed in 10 patients (16.7%) at 1-year. HD mapping allowed the evaluation of the detailed activation patterns of the PVs, and passively-activated segments may represent muscular discontinuity. Partial antral ablation of directly-activated antral segments only was feasible and effective for a PVI.

Growth zone segmentation in the milkweed bug Oncopeltus fasciatus sheds light on the evolution of insect segmentation

One of the best studied developmental processes is the Drosophila segmentation cascade. However, this cascade is generally considered to be highly derived and unusual. We present a detailed analysis of the sequential segmentation cascade of the milkweed bug Oncopletus fasciatus, as a comparison to Drosophila, with the aim of reconstructing the evolution of insect segmentation. We analyzed the expression of 12 genes, representing different phases during segmentation. We reconstruct the spatio-temporal relationships among these genes And their roles and position in the cascade. We conclude that sequential segmentation in the Oncopeltus germband includes three phases: Primary pair-rule genes generate segmental gene expression in the anterior growth zone, followed by secondary pair-rule genes, expressed in the transition between the growth zone and the segmented germband. Segment polarity genes are expressed in the segmented germband. This process generates a single-segment periodicity, and does not have a double-segment pattern at any stage.

Research on Phase Synchronization Strategies for Diesel Engines to Startup Quickly

Valid and quick phase synchronization is essential to diesel engine operation, with impacts on the starting time and emissions. This paper presents an innovative wheel shape of camshaft with four long teeth and four short teeth, which plays a fundamental role in the proposed phase synchronization strategies. A dynamic validity-check algorithm of camshaft and crankshaft sensor signals is developed as a premise. Specifically, the segment pattern matching method is used in the rapid phase synchronization strategy that is applicable given valid camshaft and crankshaft signals. A combination of trial injections and the pattern matching method is applied when either the camshaft or crankshaft sensor signal is missing in the limp home mode. Bench test results showed that phase synchronization could be realized within 180 crankshaft angles, and that the phase synchronization strategies in the limp home mode were feasible.

RNase reverses segment sequence in the anterior of a beetle egg (Callosobruchus maculatus, Coleoptera)

The genetic regulation of anterior-posterior segment pattern development has been elucidated in detail for Drosophila, but it is not canonical for insects. A surprising diversity of regulatory mechanisms is being uncovered not only between insect Orders, but also within the Order of the Diptera. This raises the question whether the same diversity of regulatory mechanisms exists within other insect Orders. This paper draws attention to the promise of the pea beetle Callosobruchus maculatus for elucidating the evolution of pattern regulation mechanisms in Coleoptera and other insect Orders. Introduction of RNase in eggs of Callosobruchus replaces anterior segments with posterior segments oriented in mirror image symmetry to the original posterior segments (double abdomens). Reversal is specific for RNase activity, for treatment of the anterior egg pole and for cytoplasmic RNA. Yield depends on developmental stage, enzyme concentration and temperature. A maximum of 30% of treated eggs reversed segment sequence after puncture in 10.0 μg/ml RNase S reconstituted from S-protein and S-peptide at 30 °C. This result sets the stage for an analysis of the genetic regulation of segment pattern formation in the long germ embryo of the Coleopteran Callosobruchus and for comparison with the short germ embryo of the Coleopteran Tribolium.