Title: The Fa(r)st or the Spurious - Pulmonary vein cycle length – Is it the fuel driving persistent AF, or simply just fumes?Authors: Sandeep Prabhu1,2,3 and Louise Segan1,2,3

Abstracts from the 27th Annual International Atrial Fibrillation Symposium January 13-15, 2022

Metadynamics simulation has been used to describe the conformational energy landscapes of several helical quinoline oligoamides bearing β-pinene-derived pyridine at either the C or N terminus. Based on the experimental results, helix-sense preference for four types of foldamers with the chiral terminal group has been verified. To compare to the key factors of inducing handedness to helical-sense preference, a terminal group with three hydrogen bond sites is designed and corresponding foldamers are built. The calculated results show the delocalization effect and steric hindrance mainly responsible for a particular helix-sense preference for the investigated foldamers. The more hydrogen bonds between the terminal group and oligoamide units are formed, the more stable foldamers are.

long-term survival after lung transplantation has increased over recent years, but still fall short of providing extensive life expectancy for more than 10 years.

Detailed theoretical investigations on their structural and electronic properties of two-dimensional (2D) monofluorinating phenethylammonium perovskite are required to deeply understand the origin of the crystal structural and optoelectronic differences caused by organic spacers. Herein, formation energy, non-covalent interaction, band structure, exciton binding energy, carrier mobility and optical absorption spectra of 2D monofluorinating phenethylammonium lead iodide perovskite were calculated using density functional theory. Results show that steric effect leads to the orientational disorder of spacers in ortho-fluorinating phenethylammonium perovskite and weak interaction leads to the herringbone configuration of spacers in meta-fluorinating phenethylammonium perovskite. Exciton binding energy significantly influences the short circuit current density (JSC) of fluorophenethylammonium-based 2D perovskites, which can well explain the experimental trends of JSC. Formation energy analysis of perovskites with the same chemical components but different crystal structures and exciton binding energy calculation can be additional strategies in high-throughput screening for high-performance 2D perovskites.

The gut microbiota of bees affect nutrition, immunity, and host fitness, yet the role of diet, sociality, and geographic variation in determining microbiome structure, including strain-level diversity and relatedness, remain poorly understood. Here, we use full-length 16S amplicon sequencing to compare the crop and gut microbiomes of two incipiently social carpenter bee species, Xylocopa sonorina and Xylocopa tabaniformis, from multiple geographic sites within each species’ range. We found that Xylocopa species share a set of core taxa consisting of Bombilactobacillus, Bombiscardovia, and Lactobacillus apis, found in >95% of all individual bees sampled, and Gilliamella and Apibacter were also detected in the gut of both species with high frequency. The crop bacterial community of both species was comprised nearly entirely of Apilactobacillus with occasionally abundant nectar bacteria. Despite sharing core taxa, Xylocopa species’ microbiomes were distinguished by multiple bacterial lineages, including species-specific strains of core taxa. In both bee species, bacterial species exhibited geographic patterns in the presence of specific sequence variants. The use of long-read amplicons revealed otherwise cryptic species and population-level differentiation in core microbiome members which was masked when a shorter fragment of the 16S (V4) was considered. We conclude that these Xylocopa species host a distinctive microbiome, similar to that of previously characterized social apids, which suggests that further investigation to understand the evolution of bee microbiome and its drivers is warranted.

Background: Pediatric bronchoscopy is an important tool in pediatric pulmonology. However, the practices involved in the procedure are variable. Objective: To evaluate prevalent practice and variations in pediatric flexible bronchoscopy in India. Methods: An online survey conducted between September 2018 to March 2019 via Google forms. The survey was sent to members of the Respiratory Chapter of IAP, personal contacts, and members of Indian Chest Society. Physicians performing flexible bronchoscopy in children were asked to respond. Survey had 95 questions in seven domains including patient preparation, sedation, procedural aspects, monitoring, bronchoscope cleaning, and complications. Results: The survey received 24 (14 in private sector) complete responses from 14 cities. Pediatric bronchoscopy was mainly done for diagnostic purposes. Conscious sedation was used by most (19, 79%). Midazolam plus fentanyl 9 (37.5%) was the preferred sedation regimen. Routine atropine was used by 4 (16%). For topical anaesthesia- nebulized only, both nebulized and spray as go, and spray as go lignocaine only was used by 1 (4.2%), 6 (25%), and 17 (71%) centres, respectively. The methods of providing oxygen during bronchoscopy were free flow (9,37.5%), nasal prongs (8,33.3%), mask (6,25%), and LMA (1,4.2%). Therapeutic procedures included removal of mucus plugs (17, 71%), bronchoscopic intubation (11, 45%) and foreign body removal (10, 41%). The suction for BAL included wall mounted suction in maximum (15, 62.5%). The number of aliquots for BAL varied from 2-6 and volume for each aliquot also varied (1-2 ml/kg or 5-10 ml). The complications rate of less than 5 % was reported by almost all. Conclusion: There is large variation in pediatric flexible bronchoscopy practices across the country highlighting the need to develop a uniform guideline.

A first principle investigation of structural, mechanical, thermodynamical, electronic and thermoelectric properties of PdTiZ (Z = Ge and Pb) was carried out using plane wave pseudopotential (PP-PW) method. The exchange-correlation was considered with the generalized gradient approximation of Perdew-Burke-Ernzerhof (PBE-GGA). The energy band structure of the sample material exhibited semiconducting energy band structure with indirect energy band gaps of 0.66 eV and 0.387 eV in PdTiGe and PdTiPb respectively with density of states being mainly dominated by the p state of Z and d states of Ti atom around the vicinity of the Fermi energy level. The sample compounds were found to be mechanically stable in their non-magnetic cubic phase. PdTiGe was found to be harder and stiffer than PdTiPb. The positive phonon modes of the compounds predicted their dynamical stabilities. Thermodynamic study revealed that pressure has a negative effect on heat capacity whereas Debye temperature increases with enhanced pressure in both the sample compounds. The thermoelectric properties of the sample compounds predicted that p-type nature of the sample compounds possess better thermoelectric performance. The room temperature Seebeck coefficient values are found to be 98.73 µV/K and 94.82 µV/K for PdTiGe and PdTiPb, respectively, whereas they reflected the S values of 245.73 µV/K and 218.77 µV/K at 1200 K at n = 1021 cm-3. The lowest value of lattice thermal conductivity (K_L) of 2.28 W/m-K and 0.98 W/m-K was observed for PdTiGe and PdTiPb respectively. The optimum dimensionless figure of merit of 0.66 (1200 K) and 0.64 (1000 K) were found for p-type PdTiGe and PdTiPb, respectively at optimum carrier concentration.

Left ventricular non-compaction (LVNC) cardiomyopathy is an uncommon unclassified or genetic myocardial disorder. Frequent premature ventricular complexes (PVCs) as unique finding in LVNC cardiomyopathy are rare. We report a case of a 36-year-old woman in whom isolated LVNC was diagnosed due to an incidental finding of PVCs in pre-operative consultation.

As a new type of gas-liquid microreactors, the gas-liquid mini-bubble column have potential applications. However, few studies on the flow fields in the mini-bubble column can be found at present. In this work, Particle Image Velocimetry (PIV) was first used to visually study the velocity fields, vorticity fields and bubble dynamics in the gas-liquid mini-bubble columns with column inner diameters of 1to 3 mm and mini-bubble diameters ranged from 0.7 to 1.3 mm. It is found that with the increase of superficial liquid velocity, bubbles rose from almost straight line to Z-shaped or S-shaped trajectory, and the bubble trajectory changed from 1-D to 3-D; when the bubble velocity changed, the bubble size and gas holdup decreased; bubble terminal velocity was controlled by bubble buoyancy and flow resistance, and increased slightly with bubble coalescence. These findings may provide basic reference for the design and scale-up of such mini-bubble column reactor.

Background: In this pilot study, we investigated whether induced sputum (IS) could serve as a viable alternative to bronchoalveolar lavage (BAL) and yield robust inflammatory biomarkers in toddlers with cystic fibrosis (CF) featuring minimal structural lung disease. Methods: We collected IS, BAL (right middle lobe and lingula) and blood, and performed chest computed tomography (CT) scans from 2-year-olds with CF (N=11), all within a single visit. Inflammatory biomarkers included 20 soluble immune mediators and neutrophil elastase (NE), as well as frequency and phenotype of T cells, monocytes / macrophages and neutrophils. Results: At the molecular level, nine mediators showed similar levels in IS and BAL (CXCL1, CXCL8, IL-1, IL-1RA, IL-6, CCL2, CXCL10, M-CSF, VEGF-A), four were higher in IS than in BAL (CXCL5, IL-1, CXCL11, TNFSF10) and two were present in IS but undetectable in BAL (IL-10, IFN-). Meanwhile, soluble NE had lower activity in IS than in BAL. At the cellular level, T-cell frequency was lower in IS than in BAL. Monocytes / macrophages were dominant in IS and BAL with similar frequencies but differing expression of CD16 (lower in IS), CD115 and surface-associated NE (higher in IS). Neutrophil frequency and phenotype did not differ between IS and BAL. Conclusions: IS collected from 2-year-olds with CF yields biomarkers of early airway inflammation with good agreement with BAL notably with regards to molecular and cellular outcomes related to neutrophils and monocytes/macrophages.

Understanding the environmental impact on the assembly of local communities in relation to their spatial and temporal connectivity is still a challenge in metacommunity ecology. This study aims to unravel underlying metacommunity processes and environmental factors that result in observed zooplankton communities. Unlike most metacommuniy studies, we jointly examine active and dormant communities using a DNA metabarcoding approach to overcome limitations of morphological species identification. We applied two-fragment (COI and 18S) metabarcoding to monitor communities of 24 kettle holes over a two-year period to unravel (I) spatial and temporal connectivity of the communities, (II) environmental factors influencing local communities, and (III) dominant underlying metacommunity processes in this system. We found a strong separation of zooplankton communities from kettle holes of different hydroperiods (degree of permanency) throughout the season, while the community composition within single kettle holes did not differ between years. Species richness was primarily dependent on pH and permanency, while species diversity (Shannon Index) was influenced by kettle hole location. Community composition was impacted by kettle hole size and surrounding field crops. Environmental processes dominated temporal and spatial processes. Sediment communities showed a different composition compared to water samples, but did not differ between ephemeral and permanent kettle holes. Our results suggest that communities are mainly structured by environmental filtering based on pH, kettle hole size, surrounding field crops, and permanency. Environmental filtering based on specific conditions in individual kettle holes seems to be the dominant process in community assembly in the studied zooplankton metacommunity. Understanding the environmental impact on the assembly of local communities in relation to their spatial and temporal connectivity is still a challenge in metacommunity ecology. This study aims to unravel underlying metacommunity processes and environmental factors that result in observed zooplankton communities. Unlike most metacommunity studies, we jointly examine active and dormant zooplankton communities using a DNA metabarcoding approach to overcome limitations of morphological species identification. We applied two-fragment (COI and 18S) metabarcoding to monitor communities of 24 kettle holes over a two-year period to unravel (I) spatial and temporal connectivity of the communities, (II) environmental factors influencing local communities, and (III) dominant underlying metacommunity processes in this system. We found a strong separation of zooplankton communities from kettle holes of different hydroperiods (degree of permanency) throughout the season, while the community composition within single kettle holes did not differ between years. Species richness was primarily dependent on pH and permanency, while species diversity (Shannon Index) was influenced by kettle hole location. Community composition was impacted by kettle hole size and surrounding field crops. Environmental processes dominated temporal and spatial processes. Sediment communities showed a different composition compared to water samples, but did not differ between ephemeral and permanent kettle holes. Our results suggest that communities are mainly structured by environmental filtering based on pH, kettle hole size, surrounding field crops, and permanency. Environmental filtering based on specific conditions in individual kettle holes seems to be the dominant process in community assembly in the studied zooplankton metacommunity.    

We report a new case of chronic recurrent annular neutrophilic dermatosis in a woman. Through our observation, we aim to make the clinician aware of this rare entity, in order to consider it among the diagnostic hypotheses of annular dermatosis, with centrifugal, recurrent and chronic evolution.

Benzalkonium chloride (BAC) is a quaternary ammonium compound commonly employed as a preservative in several multidose eye drops. Its use is associated with several adverse events, particularly when used chronically. Topically instilled BAC acts not only on superficial structures but also reaches deeper tissues (trabecular meshwork, optic nerve) and can be deleterious in patient under chronic treatment. In glaucomatous patients, BAC is the primary cause of ocular surface disease (OSD), and it can lead to significant morbidity, influence treatment compliance, quality of life, and surgical outcomes. Clinical and experimental evidence demonstrates that BAC causes instability of the tear layer, loss of goblet cells, apoptosis, subclinical neuroinflammation, and antibiotic resistance. Considering the validity of the alternative formulations (alternative preservatives or preservative-free formulations) it is unreasonable to persist in using such toxic compounds and, perhaps it is time for a moratorium on the use of BAC in eye drops.

A document by Arsalan Nadeem. Click on the document to view its contents.

High-throughput DNA sequencing technologies make it possible now to sequence entire genomes relatively easily. Complete genomic information obtained by whole genome resequencing (WGS) can aid in identifying and delineating species even if they are extremely young, cryptic or morphologically difficult to discern and closely related. Yet for taxonomic or conservation biology purposes WGS can remain cost-prohibitive, too time-consuming, and often constitute a “data overkill”. Rapid and reliable identification of species (and populations) that is also cost-effective is possible based on species-specific markers that can be discovered by WGS. Based on WGS data we designed a PCR restriction fragment length polymorphism (PCR-RFLP) assay for 19 Neotropical Midas cichlid populations (Amphilophus cf. citrinellus), that includes all 13 described species of this species complex. Our work illustrates that identification of species and populations (i.e., fish from different lakes) can be greatly improved by designing genetic markers using available “high resolution” genomic information. Yet, our work also shows that even in the best-case scenario, when whole-genome resequencing information is available, unequivocal assignments remain challenging when species or populations diverged very recently, or gene flow persists. In summary, we provide a comprehensive workflow on how to design RFPL markers based on genome re-sequencing data, how to test and evaluate their reliability, and discuss the benefits and pitfalls of our approach.

Coronary artery fistulas are rare congenital anomalies for which the ideal management strategies remain under study, with surgical repair being the mainstay of treatment in complex, aneurysmal fistulas.

Crustaceans comprise an ecologically and morphologically diverse taxonomic group. They are typically considered resilient to many environmental perturbations found in marine and coastal environments, due to effective physiological regulation of ions and hemolymph pH, and a robust exoskeleton. Ocean acidification can affect the ability of marine calcifying organisms to build and maintain mineralized tissue and poses a threat for all marine calcifying taxa. Currently, there is no consensus on how ocean acidification will alter the ecologically-relevant exoskeletal properties of crustaceans. Here, we present a systematic review and meta-analysis on the effects of ocean acidification on the crustacean exoskeleton, assessing both exoskeletal ion content (calcium and magnesium) and functional properties (biomechanical resistance and cuticle thickness). Our results suggest that the effect of ocean acidification on crustacean exoskeletal properties varies based upon seawater pCO2 and species identity, with significant levels of heterogeneity for all analyses. Calcium and magnesium content were significantly lower in animals held at pCO2 levels of 1500-1999 μatm as compared to those under ambient pCO2. At lower pCO2 levels, however, statistically significant relationships between changes in calcium and magnesium content within the same experiment were observed: a negative relationship between calcium and magnesium content at pCO2 of 500-999 μatm and a positive relationship at 1000-1499 μatm. Exoskeleton biomechanics, such as resistance to deformation (microhardness) and shell strength, also significantly decreased under pCO2 regimes of 500-999 μatm and 1500-1999 μatm, indicating functional exoskeletal change coincident with decreases in calcification. Overall, these results suggest that the crustacean exoskeleton can be susceptible to ocean acidification at the biomechanical level, potentially predicated on changes in ion content, when exposed to high influxes of CO2. Future studies will need to accommodate the high variability of crustacean responses to ocean acidification, as well as ecologically-relevant ranges of pCO2 conditions, when designing experiments with conservation-level endpoints.