La Surface Research Articles

Increased left atrial pressure is associated with fibrosis, elevated mechanical load and ventricular diastolic dysfunction in patients undergoing AF catheter ablation

Abstract Background Increased left atrial filling pressures might be a hallmark feature of atrial cardiomyopathy which has been associated with an increased incidence of atrial fibrillation (AF) recurrence even after successful pulmonary vein isolation (PVI). The interplay between left atrial pressure, measured during the ablation procedure, and other parameters characterising atrial and ventricular remodelling in patients with AF remains elusive. Methods and Results Between 2018 and 2022, 182 patients undergoing PVI for paroxysmal or persistent AF were included in the study. Mean left atrial pressure (mLAP) was measured invasively during the ablation procedure after transseptal puncture. A mLAP higher than 15 mmHg was considered the cut-off value for LA hypertension. Bipolar high-density 3D electro-anatomical maps (Carto) obtained during the procedure were used to manually quantify low-voltage (<0.5 mV) and normal voltage areas of the LA surface and a global low-voltage/normal voltage ratio index was derived. Contemporary transthoracic echocardiography data were included to evaluate LV systolic and diastolic function and blood samples were obtained post-procedurally from all patients. In bivariate linear regression analysis, mLAP reached only modest correlation with E/e’ as an imaging marker of diastolic dysfunction (R=0.31, p=0.005) (Figure 1A), with particular differences in mLAP values between patients with marked diastolic impairment (E/e’ > 15) vs. subgroups with mild dysfunction ( 8 < E/e’ ≤ 15) or normal diastolic function (E/e’ ≤ 8 ) (Figure 1B), log NT proBNP (R=0.34, p<0.001) (Figure 1C) and low-voltage/normal voltage ratio index (R=0.21, p=0.014) (Figure 1D). For a total of 158 patients, data about 1 year recurrence of AF were available, of these 22 (13.9%) had a recurrence after two procedures using cryo-energy for the index PVI and radiofrequency ablation for the re-PVI (second procedure). A Kaplan-Meier analysis and log-rank test showed a trend but no statistical significance regarding an increased AF recurrence rate between patients with and without LA hypertension (χ2 = 2.63, p= 0.09) (Figure 2). Conclusion Direct intra-procedural invasive measurement of LA pressures can offer an important and convenient novel piece of information for patients undergoing catheter ablation procedures for AF, with potential implication for post-procedural recurrence risk stratification. Atrial hypertension is only partially related to LV diastolic impairment, atrial fibrosis and myocardial mechanical load burden.

Observation of parabolic electron bands on superconductor LaRu2As2

Abstract Ru-based superconductor LaRu2As2 has been discovered exhibiting the highest critical temperature of ∼ 7.8 K among iron-free transition metal pnictides with the ThCr2Si2-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu2As2. Two distinct terminating surfaces are identified on the cleaved crystals, namely, the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of ∼ 1.0 meV. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns are attributed to quasiparticle scattering from two electron type parabolic bands.

Maintenance of sinus rhythm after electrical cardioversion to identify patients with persistent atrial fibrillation who respond favorably to pulmonary vein isolation: the pre-pacific study.

Pulmonary vein isolation (PVI) is successful in approximately 50% of patients with persistent atrial fibrillation (PsAF) at one year. Identifying pre-procedurally the patients who respond favorably to a PVI alone strategy could improve their management. The present study aims to assess the predictive value of clinical response to pre-ablation electrical cardioversion (ECV) to identify the responders to PVI. Consecutive patients undergoing catheter ablation for PsAF were retrospectively classified, as "ECV successful" vs. "ECV failure", according to the rhythm of presentation after an ECV performed ≥4 weeks. Clinical and procedural data were analyzed in both groups according to the ablation strategy applied (PVI vs. PVI + substrate modification). In total, 58 patients (39.4%) had successful ECVs and 89 (60.6%) had failed ECV. Preprocedural characteristics were similar in both groups. Compared to the ECV failure group, patients with successful ECV presented less frequently (34% vs. 60%; P = 0.004) and less extended (21.3 ± 22.2% vs. 38.9 ± 27.4% of LA surface, P = 0.008) low-voltage areas. Over 55 ± 19 weeks of follow-up, AF-free survival was similar in both groups (72.7% vs. 67.8%, p = 0.39). PVI alone resulted in 83% AF-free survival among patients in the ECV successful group at 13 months. In approximately 40% of patients with PsAF, sinus rhythm can be restored by ECV and maintained for at least 1 month prior to catheter ablation. This clinical response is associated with less abnormal substrate as identified by left atrial voltage mapping and a procedural success rate of >80% with PVI alone.

Electrochemically Assisted Construction of a La2NiO4+δ@Pt Core-Shell Structure for Enhancing the Performance and Durability of La2NiO4+δ Cathodes.

Ruddlesden-Popper oxide La2NiO4+δ (LNO) has a high ionic conductivity and good thermal match with the electrolyte of solid oxide fuel cells (SOFCs); however, LNO suffers from performance decay owing to the La surface segregation under the operation conditions of SOFCs. Herein, we report an in situ electrochemical decoration strategy to improve the electrocatalytic activity and durability of LNO cathodes. We show that the electrochemical polarization leads to in situ construction of the LNO@Pt core-shell structure, significantly suppressing the detrimental effect of La surface segregation on the LNO cathode. The initial peak power density of a single cell with the LNO cathode is 0.71 W cm-2 at 750 °C, increasing to 1.39 W cm-2 by the in situ construction of the LNO@Pt core-shell structure after polarization at 0.5 A cm-2 for 20 h. The LNO@Pt core-shell structure is also highly durable without noticeable performance degradation over the duration of the test for 180 h. The findings shed light on the design and fabrication of highly active and durable LNO-based cathodes for SOFCs.

Tunability of Hybrid Silica Xerogels: Surface Chemistry and Porous Texture Based on the Aromatic Precursor.

The interest in new materials with specific properties has increased because they are essential for the environmental and technological needs of our society. Among them, silica hybrid xerogels have emerged as promising candidates due to their simple preparation and tunability: when they are synthesised, depending on the organic precursor and its concentration, their properties can be modulated, and thus, it is possible to prepare materials with à la carte porosity and surface chemistry. This research aims to design two new series of silica hybrid xerogels by co-condensation of tetraethoxysilane (TEOS) with triethoxy(p-tolyl)silane (MPhTEOS) or 1,4-bis(triethoxysilyl)benzene (Ph(TEOS)2 and to determine their chemical and textural properties based on a variety of characterisation techniques (FT-IR, 29Si NMR, X-ray diffraction and N2, CO2 and water vapour adsorption, among others). The information gathered from these techniques reveals that depending on the organic precursor and its molar percentage, materials with different porosity, hydrophilicity and local order are obtained, evidencing the easy modulation of their properties. The ultimate goal of this study is to prepare materials suitable for a variety of applications, such as adsorbents for pollutants, catalysts, films for solar cells or coatings for optic fibre sensors.

PO-03-095 SEX-RELATED DIFFERENCES IN ATRIAL SUBSTRATE IN PATIENTS UNDERGOING PULMONARY VEIN ISOLATION; A PROSPECTIVE, MULTICENTER STUDY

Sex-related differences have been reported among patients undergoing pulmonary vein isolation (PVI). Atrial substrate plays a major role in the outcomes after ablation but sex-related differences in atrial substrate have never been described in detail. We sought to analyze sex-related differences in atrial remodeling (spontaneous low-voltage zones (LVZ)) and their clinical relevance after PVI. We conducted a prospective multicenter study, including consecutive patients undergoing first PVI-only AF ablation. LVZs were analyzed on high-density electroanatomical maps collected with multipolar catheter, prior to PVI. 262 patients (61±11 years, 31% females, 50% persistent AF) were followed for 28 months. In women, LVZs were larger (10% vs. 4% of LA surface (p < 0.001)) and more women had high-burden (>15%) LVZs (24% vs. 8% (p < 0.001)). In spite of women having more advanced atrial remodeling, AF recurrence-free survival was similar between men and women (Log-Rank p=0.2). The presence of >5% LVZ was significantly associated with recurrence in men (HR:3.0, p<0.001) but not in women (HR:1.9, p=0.07). In women, only >15% LVZ was associated with recurrence (HR: 2.7, p=0.02). Women have more widespread LVZ in all LA regions. Despite more extensive atrial remodeling, the efficacy of first PVI-only ablation is similar in men and women, and LVZs become prognostic in women only at high burden (>15%). LVZs seem to have a different prognostic role in men and women.

How do the skin barrier and microbiome adapt to the extra-uterine environment after birth? Implications for the clinical practice.

The multiple protective functions of the skin derive from the interactions between epithelial skin and immune cells as well as the commensal microbiota. Developed in the last trimester of intra-uterine life, the skin barrier adapts dynamically after birth. Specific differences in the structure and physiology have been disclosed between infant and adult skin. The stratum corneum of infants is thinner and structured by thicker corneocytes with a more anisotropic surface in comparison to adult skin. Lower levels of the natural moisturizing factor and its constituents, together with the increased protease activity in the epidermis result in dry baby skin and ongoing adaptation of the desquamation to the extra-uterine environment. Infant epidermis is characterized by an accelerated proliferation rate and clinically competent permeability barrier in term neonates, despite the higher baseline values of transepidermal water loss in infants. The skin surface of newborns is less acidic, which could increase susceptibility to diaper and atopic dermatitis. Immediately after birth, skin is colonized by commensal bacteria-a process dependent on the mode of delivery and of major importance for the maturation of the immune system. Skin bacterial diversity and dysbiosis have been related to different pathology such as atopic and seborrheic dermatitis. This paper focuses on the ongoing structural, functional and biochemical adaptation of the human skin barrier after birth. We discuss the interactions on the 'skin barrier/ microbiota/ immune system' axis and their role in the development of competent functional integrity of the epidermal barrier.

Enlarged rete pegs with excessive accumulation of melanosomes leading to darker aging spots revealed by histomorphological measurements of internal structures of the epidermis.

Various histological studies of facial pigmented spot sites such as solar lentigo have been reported, but few studies have used quantitative indices by histomorphometric analysis of the internal structure of pigmented spot sites using non-invasive methods. In the present study, to quantitatively elucidate morphological changes in the epidermis in male, darker-pigmented spots and female, light-pigmented spots, indices that characterize the internal structure of the epidermis in pigmented spot sites were measured using in vivo confocal laser scanning microscopy (CLSM). The darkness of pigmented spots on the cheeks of 69 women and 43 men was analysed using image analysis software. The L* value was calculated from RGB values obtained from facial images. The internal structures of pigmented spots on the cheeks of 13 subjects were observed by CLSM. Various parameters were measured using CLSM images from the surface of the stratum corneum to the bottom of the dermal papillae, including the thickness of the epidermis, melanosome content, and shape of the dermal papillae. Mean ΔL* values between pigmented spots and non-pigmented areas of male subjects were significantly increased in the 40s and 50s compared with those of female subjects. Conspicuous pigmented spots increased in the 40s in male subjects and the 50s in female subjects. In CLSM observations, significant increases in the thickness of the epidermis and melanosome content were confirmed in pigmented spots compared with surrounding non-pigmented areas. In particular, melanosome content in the male subject group with dark-coloured pigmented spots increased significantly to about eight times that of non-pigmented areas, and more than double that of the male subject group with light-coloured pigmented spots. From the measurements of quantitative parameters, morphological changes in the epidermis were clearly related to the surface colour tone of pigmented spots. Darker pigmented spot sites tended to show longer rete pegs in the epidermis. Accumulation of melanosomes in epidermal basal cells could be considered to increase with the degree of elongation of rete pegs at pigmented spot sites and, thus, induce darker pigmented spots.

Chronic Ablation Lesions after Cryoballoon and Hot Balloon Ablation of Atrial Fibrillation.

Chronological changes in ablation lesions after cryoballoon ablation (CBA) and hot balloon ablation (HBA) of atrial fibrillation (AF) remain unclear. Of 90 patients who underwent initial balloon-based catheter ablation of AF and cardiac magnetic resonance imaging (cMRI) 3 months after ablation, data from 48 propensity score-matched patients (24 per group; 34 males; age 62±10 years) were analyzed. High-density pulmonary vein-left antrum (PV-LA) voltage mapping was performed after PV isolation, and low voltage areas around the PV ostia were defined as the total acute ablation lesion area (cm2). cMRI-derived dense fibrotic tissue localized around PVs was defined as the total chronic ablation lesion area (cm2). The percentage of total ablation lesion areas to total PV-LA surface area (%ablation lesion) was calculated during each phase, and %acute ablation lesion and %chronic ablation lesion areas were compared in patients who had undergone CBA and HBA. The %acute ablation lesion area was larger for the CBA group than for the HBA group (30.8±5.8% vs. 23.0±5.5%, p < 0.001). There was no difference in %chronic cMRI-derived ablation lesion area (24.8±10.8% vs. 21.1±11.6%, p = 0.26) between groups. The rates of chronic AF recurrence were 12.5% and 8.3%, respectively (p = 0.45; log-rank test). LA volume and LA surface area were strongly associated with AF recurrence, but %chronic ablation lesion area was not (27±8% vs. 23±12%, p = 0.39). Large acute ablation lesions after CBA were smaller during the chronic phase. The size of chronic ablation lesions and the rate of AF recurrence were both similar for CBA and HBA.

Systematic identification of low voltage-high frequency electrogram zones at sites of left atrial reentrant tachycardia termination

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abbott Background Localization of the narrow isthmus of conduction of left atrial local and macro reentrant tachycardia (LAMRT) circuits within scar tissue is challenging. (Panel A). Near-field (NF) electrograms are often obscured by and difficult to distinguish from far-field (FF) activation. The peak frequency (PF) associated with bipolar electrograms is a novel parameter which may distinguish between NF and FF signals. (Panel B). However, the potential value of PF for LAMRT ablation has never been evaluated. Purpose 1) To quantify the percentage of LA surface with low voltage (LV) and NF signals. 2) To study the proportion of LAMRT ablation sites which were located within a LV-NF region or in the vicinity of it (&amp;lt;10 mm away). Methods LART bipolar voltage and activation maps were generated with a 16-pole grid catheter (HD-Grid) during tachycardia. (Panels A,B). PF maps were retrospectively computed (Panels C,D). LV zones were defined according to a cutoff &amp;lt;0.3mV. Four different PF cut-off values (&amp;gt;250, &amp;gt;300, &amp;gt;350 and &amp;gt;400 Hz) were assessed in the delineation of overlapping LV-NF regions. (Panel E) Results 16 consecutive patients with 24 LAMRT’s targeted for ablation were prospectively enrolled. 21/24 LAMRT’s were terminated by radiofrequency application. (Panel F). The LV area represented 47.7±14% of the LA surface. The LV-NF area represented 8.2±6.2%, 5.2±5.4%, 3.4±7.4% and 3.3±4.1% of the LA surface by using 250, 300, 350, and 400 Hz PF cutoffs respectively. There were 2.1±1 (range 0-3), 0.9±0.8(range 0-3), 0.5±0.6 (range 0-2) and 0.5±0.6 (range 0-2) LV-NF areas per patient using 250, 300, 350 and 400 Hz PF cutoffs respectively. At the optimal PF cutoff &amp;gt; 250Hz and voltage &amp;lt; 0.3mV, the site of tachycardia termination by radiofrequency application was found inside of a LV-NF region in 13/21 LAMRTs (sensitivity 68.4%), and within 1cm of a LV-NF region in 19/21 LAMRTs (sensitivity 89.5%) respectively. Conclusion 1. Left atrial reentry termination sites by radiofrequency application are often within or nearby LV-NF areas as identified by the PF and voltage analysis of bipolar electrograms. 2. Beyond conventional substrate mapping, the systematic identification of high frequency activity within the low voltage zone holds promise for rapid identification of isthmus conduction critical to LAMRTs.

The Reliability of Automated Three-Dimensional Echocardiography-HeartModelA.I. Versus 2D Echocardiography Simpson Methods in Evaluation of Left Ventricle Volumes and Ejection Fraction in Patients With Left Ventricular Dysfunction.

Background:Two-dimensional echocardiography (2DE) Simpson methods is the most frequently used imaging modality to assess Left ventricular ejection fraction (LVEF). LVEF is an important predictor of morbidity and mortality in a wide range of patients and clinical scenarios. Despite its importance in prognosis and clinical decision making, most echocardiography laboratories currently determine EF primarily by visual estimation, which is highly experience-dependent and sensitive to intra- and inter-observer variability and suboptimal accuracy and repeatability. Over the last decade, 3-dimensional echocardiography (3DE) has become increasingly implemented in clinical practice. The automated 3D HeartModelA.I. tracks every frame over the cardiac cycle using 3D speckle technology. HeartModelA.I. is a fully automated program that simultaneously detects LA and LV endocardial surfaces using an adaptive analytics algorithm that consists of knowledge-based identification of initial global shape and orientation followed by patient-specific adaptation.Objective:The objective of the study was to compare the automated 3D HeartModelA.I echocardiography and 2D Simpson methods echocardiography in evaluation of the left ventricular ejection fraction and left ventricular volumes in patients with left heart dysfunction.Methods:The study prospectively enrolled 165 patients with symptoms of LV dysfunction (ischemic or nonischemic) and New York Heart Association (NYHA) functional class I-III, referred for an echocardiographic study to evaluate the LV volumes and LV ejection fraction (LVEF) during the period from March 2020 to March 2022. Echocardiographic images were acquired by experienced echocardiographers using a commercially available Philips EPIQ machine (Koninklijke Philips Ultrasound, USA) equipped with X5-1 Matrix probe for 2DE and DHM 3DE acquisitions, respectively.Results:2D Simpson methods echocardiography results for estimated LVEF were 38.43 ± 1.70 in patients with NYHA class I-II, 30.53 ± 1.60 in patients with NYHA class III. Using 3D Heart Model, LVEF were 38.23 ± 1.71 in patients with NYHA class I-II and 30.27 ± 1.50 in patients with NYHA class III. The results of 2D Simpson methods echocardiography for estimated LVEDVi in NYHA class I-II and NYHA class III were 99.06 ± 6.36 ml/m2, 121.96 ± 2.93 ml/m2 respectively, LVESVi were 60.91 ± 3.91 ml/m2, 84.74 ± 2.70 ml/m2 respectively, for 3D Heart Model, LVEDVi in NYHA class I-II and NYHA class III were 100.07 ± 6.72, 121.38 ± 3.01 ml/m2 respectively, LVESVi were 61.75 ± 3.94 ml/m2, 84.73 ± 2.33 ml/m2 respectively. 2DE measurement of LV volumes and EF was completed in 6.1 ± 0.8 min. per patient. 3DE HeartModelA.I acquisition and analysis in most patients was completed in <3.2 min., an average time of 2.9 ± 1.3 min. per patient. The result of our study shows that the 3D HeartModelA.I. is a reliable and robust method for LVEF and LV volume analysis, which has similar results to 2D echocardiography performed by experienced sonographers. In this study, we found that 3DE DHM fully automated tool is also significantly faster than 2DE analysis and thus can help overcome the time-consuming nature and its present a strong argument for its incorporation into the clinical workflow. In this study, we found that 3DE DHM fully automated tool is also significantly faster than 2DE analysis and thus can help overcome the time-consuming nature and its present a strong argument for its incorporation into the clinical workflow.Conclusion:3D DHM provides fast and accurate LV volumes and LVEF quantitation, as it avoids geometric assumptions and left ventricular foreshortening, has better reproducibility and has incremental value to predict adverse outcomes in comparison with conventional 2DE. In the future major benefit of AI in echocardiography is expected from improvements in automated analysis and interpretation to reduce workload and improve clinical outcome.

Direct Seeding and Transplanting Influence Root Dynamics, Morpho-Physiology, Yield, and Head Quality of Globe Artichoke.

The objective of this two-year field study was to assess the influence of stand establishment methods (direct seeding or transplanting) on root growth dynamics, shoot morphology, leaf physiology, yield, and quality of globe artichoke (Cynara cardunculus). Three artichoke cultivars were evaluated, ‘Green Globe Improved’ (GGI), ‘Imperial Star’ (IS), and ‘Romolo’ (ROM). Plants established with the transplanting method had higher mean root length intensity (La), root length, and root surface area as compared to plants established by direct seeding. The topsoil (0–20 cm) had on average higher La, root length, and root surface area than deeper soil profiles. Transplanted plants had higher plant shoot width and leaf area index (LAI) chlorophyll content index (SPAD) than direct seeded plants at the vegetative stage in 2015. The improvement of root and shoot growth in transplants (compared to direct seeding) also resulted in higher (p < 0.05) marketable yield (21.1 vs. 19.9 ton ha−1 in 2015 and 18.3 vs. 13.7 ton ha−1 in 2016). Additionally, 46–50% of the total yield occurred during the first 30 days of harvest in the transplanting method compared to 13–38% for direct seeding. No significant differences were found between planting methods or cultivars in leaf-level gas exchange (photosynthesis, stomatal conductance, and transpiration) and cynarin concentration in the marketable heads. Although chlorogenic acid was similar in both establishment methods in 2015, direct seeding had higher concentration in 2016. Comparing cultivars, GGI had higher root length, surface area, root volume, and earlier and higher marketable yield than ROM. However, ROM had higher mean root length intensity (La; total root length per specific area in soil profile) than GGI in both growing seasons. This study showed significant and consistent improvements in root and shoot traits, and yield for transplants as compared to direct seeded plants.

Standardised computed tomographic assessment of left atrial morphology and tissue thickness in humans.

AimsLeft atrial (LA) remodelling is a common feature of many cardiovascular pathologies and is a sensitive marker of adverse cardiovascular outcomes. The aim of this study was to establish normal ranges for LA parameters derived from coronary computed tomographic angiography (CCTA) imaging using a standardised image processing pipeline to establish normal ranges in a previously described cohort.MethodsCCTA imaging from 193 subjects recruited to the Budapest GLOBAL twin study was analysed. Indexed LA cavity volume (LACVi), LA surface area (LASAi), wall thickness and LA tissue volume (LATVi) were calculated. Wall thickness maps were combined into an atlas. Indexed LA parameters were compared with clinical variables to identify early markers of pathological remodelling.ResultsLACVi is similar between sexes (31 ml/m2 v 30 ml/m2) and increased in hypertension (33 ml/m2 v 29 ml/m2, p = 0.009). LASAi is greater in females than males (47.8 ml/m2 v 45.8 ml/m2 male, p = 0.031). Median LAWT was 1.45 mm. LAWT was lowest at the inferior portion of the posterior LA wall (1.14 mm) and greatest in the septum (median = 2.0 mm) (p < 0.001). Conditions known to predispose to the development of AF were not associated with differences in tissue thickness.ConclusionsThe reported LACVi, LASAi, LATVi and tissue thickness derived from CCTA may serve as reference values for this age group and clinical characteristics for future studies. Increased LASAi in females in the absence of differences in LACVi or LATVi may indicate differential LA shape changes between the sexes. AF predisposing conditions, other than sex, were not associated with detectable changes in LAWT.Clinical trial registration:http://www.ClinicalTrials.gov/NCT01738828.

Heterolithic Lower Rewa Sandstone of the Neoproterozoic Rewa Group, Vindhyan Basin, U. P., India: An example of tidal point bar

The Lower Rewa Sandstone of the Rewa Group exposed in Drummondganj ghat area is about 15 m thick; it shows well developed features of tidal and wave origin. The sandstone succession characterized by Inclined Heterolithic Strata (IHS) is composed of three lithofacies associations namely, i) Sandstone lithofacies association (A), ii) Siltstone lithofacies association (B) and iii) Shale lithofacies association (C). These three lithofacies associations are repetitive and signify vertically stacked parasequences, which are further divisible into smaller hemicycles showing fining upward in terms of grains size and lithology. The studied section is characterized by heterolithic facies, lateral accretion elements (LA surfaces) with tide generated features such as cross-beddings with mudstone drapes, lenticular and wavy bedding, often of wave origin, suggesting a tidal point bar of a sinuous estuarine channel formed along coast line having momentous tidal action, superimposed by significant wave action. The upper part of the section, characterized by erosionally based cross-bedded sand-bodies with occasional mudstone drapes and current modified wave ripples, indicates translation of river-dominated inner part of an estuarine channel over the mixed-energy zone of the estuary in the sense of Dalrymple et al. (1992). The complete Lower Rewa Sandstone represents a 3rd order Highstand Systems Tract (HST). Palaeocurrent pattern is polymodal suggesting subtidal to intertidal sedimentation whereby sediment was moved mainly by tidal action with intermittent wave activity. Petrographic study reveals that the fine to very-fine grained sandstone is quartzarenite, which has been derived from a stable cratonic uplifted basement.

Long-range focusing of magnetic bound states in superconducting lanthanum

Quantum mechanical systems with long-range interactions between quasiparticles provide a promising platform for coherent quantum information technology. Superconductors are a natural choice for solid-state based quantum devices, while magnetic impurities inside superconductors give rise to quasiparticle excitations of broken Cooper pairs that provide characteristic information about the host superconductor. Here, we reveal that magnetic impurities embedded below a superconducting La(0001) surface interact via quasiparticles extending to very large distances, up to several tens of nanometers. Using low-temperature scanning probe techniques, we observe the corresponding anisotropic and giant oscillations in the LDOS. Theoretical calculations indicate that the quasi-two-dimensional surface states with their strongly anisotropic Fermi surface play a crucial role for the focusing and long-range extension of the magnetic bound states. The quasiparticle focusing mechanism should facilitate the design of versatile magnetic structures with tunable and directed magnetic interactions over large distances, thereby paving the way toward the design of low-dimensional magnet–superconductor hybrid systems exhibiting topologically non-trivial quantum states as possible elements of quantum computation schemes based on Majorana quasiparticles.

The surface of complex oxides; ion beam based analysis of energy materials

LEIS depth profiles, obtained by low energy (0.5 keV) Ar+ sputtering, have been analysed for the mixed conducting oxide material La0.6Sr0.4Co0.2Fe0.8O3-δ. Samples have been examined after differing thermal treatments to examine the sub-surface reorganisation of the cation species. The profiles have shown considerable changes, but these are not strongly correlated with the thermal treatments. The similarity between the profiles suggests that preferential sputtering effects can dominate the sub-surface region (~1–3 nm) where sputtering has not reached equilibrium. Preferential sputtering of oxygen in oxide materials is well known, but here we provide evidence of the preferential sputtering of the cationic species in a complex multicomponent oxide. Of note is strong enrichment (~30%) of the sputtered surface with the heaviest of the elements, La. Simulations using the code TRIDYN have confirmed the observations, in particular, La surface enrichment and the fluence needed to achieve steady state sputtering of > 3 × 1016cm−2.

Chaos Many-Body Engine module for estimating pentaquark production in proton–proton collisions at CBM energies

In Grossu et al., (2019) we proposed a Chaos Many-Body Engine (CMBE) quark toy-model for the Compressed Baryonic Matter (CBM) energies. We started from the following assumptions: (1) the system can be decomposed into a set of two or three-body quark “elementary systems”, i.e. “white” color charged, mesonic or baryonic systems; (2) the bi-particle force is limited to the domain of each elementary system; (3) the physical solution conforms to the minimum potential energy requirement. In the present work we used graph theory for identifying those sets (clusters) of elementary systems close enough to form a bound system (through the exchange of same color charged quarks). In this approach, the cluster production could be understood as an effect of the chaotic behavior of the system. As a direct application, we estimated the pentaquark production probability obtained in p + p collisions, at a center-of-mass energy between 10 and 100 GeV New version program summaryProgram Title: Chaos Many-Body Engine (CMBE)CPC Library link to program files:http://dx.doi.org/10.17632/rh5txj3n4g.2Licensing provisions: GPLv2Programming language: C# 7.3.External routines: BigRational structure (Microsoft).Journal reference of previous version: Computer Physics Communications 239C (2019) 149-152Does the new version supersede the previous version?: Yes.Nature of problem: Estimate the Pentaquark production in nuclear relativistic collisions.Solution method: Clustering algorithm for identifying all five-body quark white systems.Reasons for the new version: Added the Pentaquark identification new feature.Summary of revisions:•Migration from .Net Framework 4.0 to .Net Framework 4.7.1•In [1] we implemented a quark confinement algorithm for decomposing the system into a set of two or three-body quark “elementary systems”, i.e. “white” color charged, mesonic or respectively, baryonic systems, in agreement with the minimum potential energy requirement. In this work we added a new O(n3) algorithm (QcdQuarkBagPentaQuarkAlgorithm class), developed in agreement with the SOLID principles, for the identification of those sets (clusters) of elementary systems close enough to form a bound system (through the exchange of same color charged quarks). Taking this into account the system was associated with an undirected graph G [2,3], whose nodes are the elementary systems. Two nodes are connected if the distance between their geometrical centers is lower than the sum of their radii. Thus, each cluster could be associated to a maximal connected subgraph of G.•Unit tests (QcdQuarkBagPentaQuarkAlgorithmTests class) for checking the new algorithm.•In [1] we proposed a quark toy-model for proton–proton collisions at CBM energies [4]. The model was extended for estimating the pentaquark [5] production probability, as seen in Fig. 1. In this approach, the pentaquark production could be understood as a direct effect of the chaotic behavior of the system [6,7]. Thus, for each center-of-mass energy (s∈10,100GeV) we simulated 2,000 events by choosing Simulations\\Quark Collision from the menu and storing the pentaquark multiplicity at t=300 Fm/c in the quark.pentaquark.log.csv file, generated into the simulation output folder. The collision parameter was given random values in the [0.2, 1.1] Fm range.ReferencesI.V. Grossu, C. Besliu, Al. Jipa, D. Felea, E. Stan, T. Esanu, Implementation of quark confinement and retarded interactions algorithms for Chaos Many-Body Engine, Computer Physics Communications 239C (2019) pp. 149-152, DOI: https://doi.org/10.1016/j.cpc.2019.01.023Alan Gibbons, Algorithmic Graph Theory, Cambridge University Press, 1985.I.V. Grossu, C. Besliu, Al. Jipa, C.C. Bordeianu, D. Felea, E. Stan, T. Esanu, Code C# for chaos analysis of relativistic many-body systems, Computer Physics Communications 181 (2010) 1464–1470, https://doi.org/10.1016/j.cpc.2010.04.015A. Abuhoza et al, The CBM Collaboration, Nuclear Physics A, Volumes 904--905, 2 May 2013, Pages 1059c-1062cA. Abdivaliev, C. Besliu et al., Yad.Fiz.29, v.6, 1979.St. Grosu, Quelques effets des fluctuations de la barrière de potentiel a la surface des conducteurs, Studii si cercetari de fizica, 1, XI, 1960D. Felea, C.C. Bordeianu, I.V. Grossu, C. Besliu, Al. Jipa, A.-A. Radu and E. Stan, Intermittency route to chaos for the nuclear Billiard, EPL, 93 (2011) 42001, DOI: 10.1209∕0295−5075∕93∕42001

P1020Persistent AF patients with limited areas of low voltage have a similar benefit from pulmonary vein isolation as compared to paroxysmal AF patients: insight from the SMOP study

Abstract Background Pulmonary vein isolation (PVI) performed with radio-frequency catheter ablation (CA) is an effective therapy for atrial fibrillation (AF). However previous data have suggested that PVI is less effective in persistent (PER) vs. paroxysmal (PAR) AF. Atrial fibrosis and scar, indeed, are an important substrate involved in persistent AF, and some author correlate them to an increased rate of recurrences after CA. For this reason several adjunctive ablation strategies have been suggested for invasive treatment in PER AF pts. However, there is a lack of evidence on their effectivness in current literature. Objective the aim of our study was to assess the rate of AF recurrences in PAR and PER AF patients after a first pulmonary vein isolation (IVP) procedure, and their relationship with low voltage areas of the left atrium assessed by means of high density mapping performed before CA. Methods we analyzed 214 patients of the SMOP-AF study (Substrate Mapping as Outcome Predictor in Atrial Fibrillation Ablation), a prospective multi-centric registry enrolling patients with both PAR and PER AF undergoing a first radio-frequency CA procedure aimed to obtain permanent PVI . High-density mapping was performed in sinus rhythm using the CARTO system before PVI. Areas with less than 0,5 mV on mapping were defined as low voltage zone (LVZ); LVZ was indexed on the atrial area. Comparisons were made by cross-tables and Chi-square test or Student T test. Results Patients with PER AF (n = 44, 21%) were older (63 ± 9 vs 58 ± 10 yrs, p = 0.01), but notably with no difference in LVEF and atrial dimensions as compared to pts with PAR AF. In addition no statistical difference was observed in procedural variables, except for a greater LVZ area on atrial mapping (8 ± 18 % vs. 5 ± 15 %, p = 0.04) and a longer p wave duration (115 ± 21 msec vs. 103 ± 18 msec, p = 0.01) in pts with PER AF. The incidence of recurrence in the overall population was 15.3% at 3 months and 13.7% from 3 to 12 months: there was no statistical difference in success-rate between PER and PAR pts (respectively 79,5% vs 86% p value = 0.315 in blanking period and 85,3% vs 86,5% p value = 0.8 at 3-12 months follow-up). No statistical difference was observed for ablation variables (number of lesion, contact force, force time integral) in pts with vs. without recurrences. Conclusion Our study showed that pulmonary vein isolation alone seems to be as effective in paroxismal and persistent AF patients with low degree of left atrial fibrosis. Our data call into question the idea that PVI alone is not effective in PER AF. High density mapping of the LA could help to identify a subset of PER AF patients with a limited extension of low voltage areas (i.e around 10% of the overall LA surface) that could benefit from PVI without adjunctive ablation strategies. Our data needs to be confirmed in a longer follow-up.

P318 Left atrial dysfunction assessed by echocardiography in relation to left atrial fibrosis in patients undergoing ablation for atrial fibrillation

Abstract PURPOSE Left atrial (LA) fibrosis is the hallmark of LA remodeling in atrial fibrillation (AF), alters LA function and may predict poor catheter ablation (CA) outcome. LA fibrosis may be assessed invasively using electroanatomical mapping (EAM) during electrophysiological study. The aim was to assess LA function parameters in relation to degree of LA fibrosis derived from EAM in patients with AF. METHODS Patients (pts) n = 39 (79% males, mean age 56+/-10) with non-valvular AF were studied with TTE and TEE before first CA during sinus rhythm. LA strain (LAS) and strain rate (LASR) were analyzed in reservoir (r), conduit (cd) and contractile (ct) phases. The velocities of mitral A, E" and A" were measured with Doppler. E/E" and LA stiffness index - the ratio of E/E" to LASr were assessed. LA appendage flow velocity (LAAv) was measured in TEE. LA volume using biplane area-length method was calculated. The EAM of LA was build using Carto System before CA. Low amplitude potentials area (LAPA) was quantitatively analyzed and expressed as a percentage of LA surface using the cut-off &amp;lt;0.5 mV to detect sites of fibrosis. LA parameters were compared between mild (LAPA &amp;lt;10%) moderate (LAPA 10-40%) and extensive degree of LA fibrosis (LAPA &amp;gt;40%) (table). RESULTS The mean LA volume was 35 ± 11 mL/m². The LAPA ranged from 2 to 78 % of LA surface. Reduced LA function was observed in the LAPA &amp;gt;40% group. Extensive LAPA altered mainly LA compliance parameters. Traditional LA systolic function parameters did not differ in relation to degree of LAPA. CONCLUSION LA compliance is mostly affected by LA fibrosis, thus LA diastolic parameters may be useful in the noninvasive assessment of LA fibrosis. Whether these parameters should be a part of the proper selection of candidates for CA requires further studies. LA function parameters LA parameters Group 1 LAPA &amp;lt;10% n = 13 Group 2 LAPA &amp;gt;10% &amp;lt;40% n = 13 Group 3 LAPA &amp;gt;40% n = 13 P-value Group 1 + 2 vs 3 Mitral A 0.55 ± 0.10 0.55 ± 0.24 0.73 ± 0.32 0.077 A" 9.19 ± 1.74 7.85 ± 1.43 7.92 ± 2.40 0.376 LASr 31.48 ± 4.52 26.48 ± 8.79 19.63 ± 6.76 &amp;lt;0.001 LAScd 17.30 ± 3.05 15.44 ± 6.93 10.91 ± 4.04 0.003 LASct 14.18 ± 5.36 11.05 ± 3.67 8.72 ± 4.78 0.024 LASRr 1.22 ± 0.19 1.24 ± 0.21 0.92 ± 0.20 &amp;lt;0.001 LASRct -1.71 ± 0.46 -1.37 ± 0.34 -1.04 ± 0.33 &amp;lt;0.001 LA stiffness 0.20 ± 0.07 0.34 ± 0.17 0.63 ± 0.29 &amp;lt;0.001 LAAv 0.83 ± 0.18 0.55 ± 0.17 0.60 ± 0.16 0.178

Lung Ultrasound–Guided Dry Weight Assessment and Echocardiographic Measures in Hypertensive Hemodialysis Patients: A Randomized Controlled Study

Left ventricular (LV) hypertrophy and dysfunction are associated with adverse outcomes in hemodialysis patients. Hypertension and hypervolemia play important roles in these cardiac abnormalities. We report on the prespecified secondary outcome, echocardiographic indexes of LV function, from a previously reported study of the effect of lung ultrasound (US)-guided dry weight reduction on systolic blood pressure. Single-blind randomized trial. 71 clinically euvolemic hypertensive hemodialysis patients in Greece and Slovenia. The active intervention group's (n=35) volume removal was guided by the total number of lung US B-lines observed every week before a midweek dialysis session. The usual-care group (n=36) was treated using standard-of-care processes that did not include acquisition of US data. 2-dimensional and tissue Doppler echocardiographic indexes at baseline and study end (8 weeks) that evaluated left and right heart chamber sizes, as well as systolic and diastolic function. Overall, 19 (54%) patients in the activeintervention and 5 (14%) in the usual-care group hadultrafiltration intensification (P<0.001) during follow-up; changes in US B-lines (-5.3±12.5 vs+2.2±7.6; P<0.001) and dry weight (-0.71±1.39 vs+0.51±0.98kg; P<0.001) significantly differed between the active and usual-care groups. Inferior vena cava diameter decreased in the active compared with theusual-care group (-0.43±4.00 vs 0.71±4.82cm; P=0.03) at study end. Left (LA) and right (RA) atrial dimensions decreased moreinthe activegroup (LA surface, -1.09±4.61vs 0.93±3.06cm2; P=0.03; RA surface-1.56±6.17 vs 0.47±2.31; P=0.02). LA volume index nominally decreased more in the active group (-2.43±13.14 vs 2.95±9.42mL/m2), though this was of borderline statistical significance (P=0.05). Reductions in LVend-diastolic diameter and volume were marginally greater in the active group. The change in LV fillingpressures was significantly different in theactive compared with the usual-care group(earlytransmitral diastolic velocities ratio [E/e'],-0.38±3.14 vs 1.36±3.54; P=0.03; Ewavedeceleration time, 35.43±85.25 vs-18.44±50.69; P=0.002]. Systolic function indexes were unchanged in both groups. In multivariable analysis, US B-line reduction was associated with a reduction in the E/e' LV ratio (OR, 4.542; 95% CI, 1.266-16.292; P=0.02). Exploratory study; small sample size. A US-guided strategy for dry weight reduction is associated with decreased cardiac chamber dimensions and LV filling pressure, but no difference in systolic performance compared with usual care in hypertensive hemodialysis patients. European Renal Association-European Dialysis and Transplant Association. Registered at ClinicalTrials.gov with study number NCT03058874.