bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-dimensional Dirac half-metal in porous carbon nitride C6N7 monolayer via atomic doping
Authors: Bafekry A , Faraji M , Hieu N N , Ang Yee Sin , Karbasizadeh S , Abdolhosseini Sarsari I , Ghergherehchi M
Published: October 2021

Motivated by the recent experimental discovery of C6N7 monolayer (Zhao et al 2021 Science Bulletin
66, 1764), we show that C6N7 monolayer co-doped with C atom is a Dirac half-metal by employing first-principle density functional theory calculations. The structural, mechanical, electronic and magnetic properties of the co-doped C6N7 are investigated by both the PBE and HSE06 functionals. Pristine C6N7 monolayer is a semiconductor with almost isotropic electronic dispersion around the Γ point. As the doping of the C6N7 takes place, the substitution of an N atom with a C atom transforms the monolayer into a dilute magnetic semiconductor, with the spin-up channel showing a band gap of 2.3 eV, while the spin-down channel exhibits a semimetallic phase with multiple Dirac points. The thermodynamic stability of the system is also checked out via AIMD simulations, showing the monolayer to be free of distortion at 500 K. The emergence of Dirac half-metal in carbon nitride monolayer via atomic doping reveals an exciting material platform for designing novel nanoelectronics and spintronics devices.
Structural and magnetic properties of CoFe2O4 ferrite nanoparticles doped by gadolinium
Authors: Nikmanesh Hossein , Jaberolansar Elnaz , Kameli Parviz , Varzaneh Ali Ghotbi , Mehrabi Mohsen , Rostami Momammad
Published: October 2021

This work’s main purpose is to investigate the effect of Gd3+ substitution on the structural, cation distribution, morphological, and magnetic characteristics of cobalt ferrite nanostructures. The nanostructures were synthesized through the sol-gel auto combustion technique. X-ray diffraction (XRD) analysis with the Rietveld refinement through the Material Analysis Using Diffraction (MAUD) program confirmed a single-phase spinel structure for lower contents of Gd3+. However, for higher concentrations, a trace of second phase GdFeO3 was evident. The crystallite size reduction from 17 to 11 nm with Gd3+ doping confirmed the formation of nanocrystalline Co–Gd ferrite. Cation distribution was another parameter inferred from the experimental data of XRD analyzed by the MAUD program. Fourier-transform infrared spectra confirmed the formation of spinel structure through two prominent vibrational modes observed at the desired wavelength range. FESEM analysis confirmed the data obtained from the XRD about the structure and morphology of the nano samples. Saturation magnetization (M
S) of the nano samples evaluated at 10 K showed a decreasing behavior from 94 to 86 emu g−1 by Gd3+ doping, while a fluctuating trend of M
S was observed at room temperature. Coercive field (H
C) evaluated at 10 K reached a maximum value of about 1145 kA m−1 for the sample CoFe1.96Gd0.04O4, and then it decreased. At the same time, H
C experienced no considerable change at 300 K. The possible concepts attributed to such a trend of H
C were also investigated. Overall, the significant impact of Gd3+ doping on the cobalt ferrite nanoparticles causes Gd–Co ferrite to have a desirable capacity of permanent magnet materials and storage of information with high density. As a result, this ferrite may be a proper candidate to be utilized, especially at lower temperatures.
Anatomical atlas of the upper part of the human head for electroencephalography and bioimpedance applications
Authors: Moura Fernando S , Beraldo Roberto G , Ferreira Leonardo A , Siltanen Samuli
Published: October 2021

Objective. The objective of this work is to develop a 4D (3D+T) statistical anatomical atlas of the electrical properties of the upper part of the human head for cerebral electrophysiology and bioimpedance applications. Approach. The atlas was constructed based on 3D magnetic resonance images (MRI) of 107 human individuals and comprises the electrical properties of the main internal structures and can be adjusted for specific electrical frequencies. T1w+T2w MRI images were used to segment the main structures of the head while angiography MRI was used to segment the main arteries. The proposed atlas also comprises a time-varying model of arterial brain circulation, based on the solution of the Navier–Stokes equation in the main arteries and their vascular territories. Main results. High-resolution, multi-frequency and time-varying anatomical atlases of resistivity, conductivity and relative permittivity were created and evaluated using a forward problem solver for EIT. The atlas was successfully used to simulate electrical impedance tomography measurements indicating the necessity of signal-to-noise between 100 and 125 dB to identify vascular changes due to the cardiac cycle, corroborating previous studies. The source code of the atlas and solver are freely available to download. Significance. Volume conductor problems in cerebral electrophysiology and bioimpedance do not have analytical solutions for nontrivial geometries and require a 3D model of the head and its electrical properties for solving the associated PDEs numerically. Ideally, the model should be made with patient-specific information. In clinical practice, this is not always the case and an average head model is often used. Also, the electrical properties of the tissues might not be completely known due to natural variability. Anatomical atlases are important tools for in silico studies on cerebral circulation and electrophysiology that require statistically consistent data, e.g. machine learning, sensitivity analyses, and as a benchmark to test inverse problem solvers.
Synchronising optical emission spectroscopy to spokes in magnetron sputtering discharges
Authors: Maaß Philipp A , Schulz-von der Gathen Volker , von Keudell Achim , Held Julian
Published: October 2021

Spokes are patterns of increased light emission, observed to rotate in front of the targets of magnetron sputtering discharges. They move through the plasma at velocities of several km s−1 in or against the

E

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×

B

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direction of the discharge. The high velocity and their initial creation at arbitrary positions render measurements of spokes challenging. For more demanding plasma diagnostic techniques that require data acquisition over multiple discharge pulses, synchronisation to the spoke movement is necessary. In this publication, we present optical emission spectroscopy of spokes in both high power impulse magnetron sputtering (HiPIMS) as well as direct current magnetron sputtering (DCMS) discharges, performed by triggering a camera on the spoke movement. Optical filters between plasma and camera allow us to isolate emission lines of metal and working gas neutrals and ions. Based on these optical measurements and previous probe studies, the dynamics of electrons drifting through spokes in both DCMS and HiPIMS is discussed. In HiPIMS, the much shorter mean free path for inelastic electron collisions enables strong ionisation inside the spoke, causing a sudden variation in electron density which leads to the distinct spoke shape. In contrast, the spoke shape for DCMS discharges seems to rather be indicative of electron energy variations.
A multifunctional electromagnetic device for vibration energy harvesting and rail corrugation sensing
Authors: Wang Yifeng , Li Shoutai , Wang Peigen , Gao Mingyuan , Ouyang Huajiang , He Qing , Wang Ping
Published: October 2021

A multifunctional electromagnetic device for harvesting rail vibration energy and sensing rail corrugation is proposed. Firstly, the optimal coil position is investigated theoretically and verified through experiments. Then, experimental frequency-sweeping tests are carried out to understand the response characteristics of the harvester. Two sections of a metro line with/without rail corrugations are selected to measure rail roughness and vibration. Using the field-measured rail vibration as excitations, the response characteristics of the harvester are investigated through indoor experiments. Experimental results demonstrate that occurrences of corrugation can be identified through time-frequency analysis of the electromotive forces of the harvester. Besides, electrical load tests under normal rail vibration demonstrate that this harvester will yield its maximum power of 18.6 mW (average power: 1.5 mW) when the resistance of the external electrical load is close to the internal resistance of the coil. The capability to energise small commercial electronic devices is verified by charging a supercapacitor, and driving LEDs, a digital clock, and a thermo-hygrometer to work, respectively. The capabilities of the harvester for powering low-power electronics and sensing rail corrugation pave the wave for designing a self-powered sensing node for rail corrugation monitoring.
Comprehensive kinetic theory of inverse sheath for a strong electron-emitting electrode in a low-pressure isotropic plasma
Authors: Din Alif
Published: October 2021

The basic kinetic theory of an electron emitting inverse sheath was presented in T Gyergyek, J Kovačič, I Gomez, J P Gunn, S Costea and M Mozetič (2020 Phys. of Plasmas
27, 023 520). Here we extend this theory to find the potential profile and kinetic energy flux in inverse sheath for floating and current carrying electron emitting electrode/wall. The values of emitted-electron temperature, number and current densities are explored for the existence and nonexistence of inverse sheath for floating and current carrying electrode/wall. For this we consider half Maxwellian velocity distribution functions of species (emitted-electron, plasma-electron and ions) at their respective emerging boundaries. The species charge densities are calculated self-consistently from the prior assumed positive sheath structure. The Poisson’s equation is then solved numerically for floating and current carrying electrode/wall with varying normalized emitted-electron and ion temperatures. The resulting inverse sheath solution is valid for limited range of emitted-electron and ion temperatures in case of floating electrode/wall. The kinetic energy flux relations for each species are derived in inverse sheath. The numerical solutions of these relations for floating and current carrying electrode/wall are presented for valid range of parameters. These solutions shows that the total or kinetic flux received by floating electrode/wall surface decreases with increasing of emitted-electron temperature and even approaches to zero for equal values of emitted-electron and plasma-electron temperatures.
In-depth research on the interpretable disruption predictor in HL-2A
Authors: Yang Zongyu , Xia Fan , Song Xianming , Gao Zhe , Wang Shuo , Dong Yunbo
Published: October 2021

In-depth research is implemented on the disruption predictor in HL-2A to improve the accuracy and interpretability of the model. For higher accuracy, four adjustments are tried to solve four corresponding problems in a baseline model. Reductive comparison experiments are designed to evaluate their contribution to performance. The result shows that these adjustments together can improve the AUC (area under receiver operating characteristic curve) of the baseline model by 0.039. For interpretability of model, an interpretation method is proposed to evaluate the real-time importance of each input signal. The result of single shot interpretation shows good coherence with the causes of disruptions. To further validate the reasonability of this interpretation method, disruption causes of shot nos. 20000–36000 are analysed to make a disruption cause dataset. Statistical analysis of the output of the interpretation algorithm on this dataset also shows a good coherence with the disruption causes. Then a Bayes classifier is developed to recognize the cause of disruption based on the interpretation algorithm’s output. This classifier has an accuracy of 71.2% on the labelled dataset, which contains 605 disruptive shots categorized into five disruption causes.
Anisotropic porous ceramic material with hierarchical architecture for thermal insulation
Authors: Zhao Nifang , Mao Anran , Shao Ziyu , Bai Hao
Published: October 2021

Porous ceramic materials are attractive candidates for thermal insulation. However, effective ways to develop porous ceramics with high mechanical and thermal insulation performances are still lacking. Herein, an anisotropic porous silica ceramic with hierarchical architecture, i.e. long-range aligned lamellar layers composed of hollow silica spheres, was fabricated applying a facile bidirectional freezing method. Due to such anisotropic structure, the as-prepared porous silica ceramic displays low thermal conductivity across the layers and high compressive strength along the layers. Additionally, the anisotropic porous silica ceramic is fire-resistant. As a proof of concept, a mini-house was roofed with the anisotropic porous silica ceramic, showing that the indoor temperature could be stabilized against environmental temperature change, making this porous ceramic a promising candidate for energy efficient buildings and other industrial applications. Our study highlights the possibility of combining intrinsically exclusive properties in engineering materials through constructing biomimetic porous structures.
Biocide effect against SARS-CoV-2 and ESKAPE pathogens of a noncytotoxic silver–copper nanofilm
Authors: Bello-Lopez J M , Silva-Bermudez P , Prado G , Martínez A , Ibáñez-Cervantes Gabriela , Cureño-Díaz Mónica Alethia , Rocha-Zavaleta L , Manzo-Merino J , Almaguer-Flores A , Ramos-Vilchis C , Rodil S E
Published: October 2021

Nanometric materials with biocidal properties effective against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) and pathogenic bacteria could be used to modify surfaces, reducing the risk of touching transmission. In this work, we showed that a nanometric layer of bimetallic AgCu can be effectively deposited on polypropylene (PP) fibers. The virucidal properties of the AgCu nanofilm were evaluated by comparing the viral loads remaining on uncoated and coated PP after contact times between 2 and 24 h. Quantification of virion numbers for different initial concentrations indicated a reduction of more than 95% after 2 h of contact. The bactericidal action of the AgCu nanofilm was also confirmed by inoculating uncoated and coated PP with a pool of pathogenic bacteria associated with pneumonia (ESKAPE). Meanwhile, no cytotoxicity was observed for human fibroblasts and keratinocyte cells, indicating that the nanofilm could be in contact with human skin without threat. The deposition of the AgCu nanofilm on the nonwoven component of reusable cloth masks might help to prevent virus and bacterial infection while reducing the pollution burden related to the disposable masks. The possible mechanism of biocide contact action was studied by quantum chemistry calculations that show that the addition of Ag and/or Cu makes the polymeric fiber a better electron acceptor. This can promote the oxidation of the phospholipids present at both the virus and bacterial membranes. The rupture at the membrane exposes and damages the genetic material of the virus. More studies are needed to determine the mechanism of action, but the results reported here indicate that Cu and Ag ions are good allies, which can help protect us from the virus that has caused this disturbing pandemic.
Asymmetric impacts of El Niño and La Niña on the Pacific–North American teleconnection pattern: the role of subtropical jet stream
Authors: Wang Ya , Hu Kaiming , Huang Gang , Tao Weichen
Published: October 2021

The asymmetric impacts of El Niño and La Niña on the Pacific–North American teleconnection pattern in boreal winter have important implications for the surface air temperature and precipitation anomalies in North America. Previous studies have shown that the varying tropical convective heating contributes to the zonal shift of the teleconnection pattern during different El Niño/Southern Oscillation phases. In this study, using reanalysis, atmospheric general circulation model (AGCM) simulations, and a linear baroclinic model, we further present that the discrepancy of the subtropical jet stream (STJ) during El Niño and La Niña also contributes to the asymmetry. The atmospheric anomalies readily extract kinetic energy and effectively develop at the exit of the STJ. During El Niño (La Niña) years, as the central-eastern tropical Pacific warms up (cools down), the meridional temperature gradient in central subtropical Pacific increases (decreases), leading to the eastward (westward) shift of the STJ. The movement of the STJ leads to the shift of the location where disturbance develops most efficiently, ultimately contributing to the asymmetry of the teleconnection pattern.
A comprehensive review of the analysis and integration of omics data for SARS-CoV-2 and COVID-19
Authors: Zhu Zijun , Zhang Sainan , Wang Ping , Chen Xinyu , Bi Jianxing , Cheng Liang , Zhang Xue
Published: October 2021

Since the first report of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, over 100 million people have been infected by COVID-19, millions of whom have died. In the latest year, a large number of omics data have sprung up and helped researchers broadly study the sequence, chemical structure and function of SARS-CoV-2, as well as molecular abnormal mechanisms of COVID-19 patients. Though some successes have been achieved in these areas, it is necessary to analyze and mine omics data for comprehensively understanding SARS-CoV-2 and COVID-19. Hence, we reviewed the current advantages and limitations of the integration of omics data herein. Firstly, we sorted out the sequence resources and database resources of SARS-CoV-2, including protein chemical structure, potential drug information and research literature resources. Next, we collected omics data of the COVID-19 hosts, including genomics, transcriptomics, microbiology and potential drug information data. And subsequently, based on the integration of omics data, we summarized the existing data analysis methods and the related research results of COVID-19 multi-omics data in recent years. Finally, we put forward SARS-CoV-2 (COVID-19) multi-omics data integration research direction and gave a case study to mine deeper for the disease mechanisms of COVID-19.
Early preantral follicles of the domestic cat express gonadotropin and sex steroid signaling potential
Authors: Kehoe S , Jewgenow K , Johnston P R , Braun B C
Published: October 2021

Key biomolecular processes, which regulate primordial ovarian follicle dormancy and early folliculogenesis in mammalian ovaries, are not fully understood. The domestic cat is a useful model to study ovarian folliculogenesis and is the most relevant for developing in vitro growth methods to be implemented in wild felid conservation breeding programs. Previously, RNA-sequencing of primordial (PrF), primary (PF), and secondary follicle (SF) samples from domestic cat implicated ovarian steroidogenesis and steroid reception during follicle development. Here, we aimed to identify which sex steroid biosynthesis and metabolism enzymes, gonadotropin receptors, and sex steroid receptors are present and may be potential regulators. Differential gene expression, functional annotation, and enrichment analyses were employed and protein localization was studied too. Gene transcripts for PGR, PGRMC1, AR (steroid receptors), CYP11A1, CYP17A1, HSD17B1 and HSD17B17 (steroidogenic enzymes), and STS (steroid metabolizing enzyme) were significantly differentially expressed (Q values of ≤0.05). Differential gene expression increased in all transcripts during follicle transitions apart from AR which decreased by the secondary stage. Immunohistochemistry localized FSHR and LHCGR to oocytes at each stage. PGRMC1 immunostaining was strongest in granulosa cells, whereas AR was strongest in oocytes throughout each stage. Protein signals for steroidogenic enzymes were only detectable in SFs. Products of these significantly differentially expressed genes may regulate domestic cat preantral folliculogenesis. In vitro growth could be optimized as all early follicles express gonadotropin and steroid receptors meaning hormone interaction and response may be possible. Protein expression analyses of early SFs supported its potential for producing sex steroids.
NRG COSIA Carbon XPRIZE: carbon-dioxide mineralization in recycled concrete wash water
Authors: Monkman Sean , Janke Travis , Hanmore Alex
Published: October 2021

Wash water is generated as a waste stream from ready-mixed-concrete production. Reuse of the water as mixture water is limited, in practice, by the negative material performance impacts associated with the water chemistry and properties; the effects are intensified with increasing content of suspended solids and age. However, this waste material can be used as a beneficial additive to concrete by profiting from the cementitious properties of the suspended solids, if variability can be reduced. A method of stabilizing this material is through CO2 treatment. The added CO2 is mineralized through a reaction with the calcium from the cement particles. This provides a calcium-carbonate coating that prevents further cement hydration, making the material predictable. This has been shown to alleviate concerns with set acceleration and inconsistencies in compressive strength. A method of CO2 treatment was tested as part of the NRG COSIA Carbon XPRIZE at a site in Calgary, Alberta. The slurry for the treatment was provided by a local concrete plant and had a specific gravity of 1.15. The simulated wash water was treated in 1000-L quantities with each treatment mineralizing an average of 40 kg of CO2. The system ran for 1600 hours of operation over 127 treatment cycles and converted 14.5 tonnes of CO2 at an average mineralization efficiency of 80%. The treated slurry was used as an additive in >300 batches of concrete where the concrete met the necessary requirements for fresh properties and setting time, while achieving a strength benefit. Replacement of 5% and 10% of batch water with treated slurry (9.4 and 18.8 kg slurry/m3 concrete) showed a strength benefit of 3% and 6% compared to a reference. The technology was selected as the winner of the NRG COSIA Carbon XPRIZE (Track B: Natural Gas) in April 2021.
Methodology for the economic evaluation of CO2 derived materials
Authors: Wong Tiffany , Zilnik Dan , Extavour Marcius , Leitch Michael
Published: October 2021

Scoring the technologies in competition for the NRG Canada’s Oil Sands Innovation Alliance Carbon XPRIZE required an economic evaluation to estimate the value created through the conversion of CO2 emissions into products. Across all of the Teams participating in the competition, 58 different materials were consumed and produced. Standardized prices and market sizes needed to be established for each of these materials to ensure a consistent evaluation across all Teams. The Standards Data Set (SDS) was created as a standardized database of economic data used in the competition. The rationale for the SDS project and the methodology for researching each material is described. Ultimately, credible material definitions using the SDS methodology were created for all materials, and some research and methodological customization were required for materials that did not have credible, publicly available market data. The methodologies for establishing credible values and market sizes for concrete, concrete admixtures and syngas are highlighted as examples of materials whose value and markets are not easily defined.
Best practices for measurement and impact on performance evaluation for novel carbon-utilization process technologies
Authors: Hansen Tim , McCabe Kevin , Chatterton Bill , Leitch Michael , Woolcock Patrick
Published: October 2021

The NRG COSIA Carbon XPRIZE—a $20 million prize competition focused on the development and scaling of innovative carbon-capture and -utilization technologies—placed credible data at the forefront of its scoring and ranking approach for the selection of prize-winners. To guarantee the quality of the submitted data, independent third-party verifiers reviewed each candidate technology and data set. While the Carbon XPRIZE contenders demonstrated a variety of CO2-utilization technologies at various levels of technical maturity and scale, it was found that early evaluation of the impact of measurements on process performance parameters via sensitivity analysis should influence the selection of instruments that have appropriate accuracy. In addition to appropriate accuracy, this assessment can lead to reduced costs associated with instrumentation rather than simply buying the ‘best’ instrument while simultaneously ensuring that uncertainties are kept as low as possible. With proper pre-planning, good engineering practice and good measurement practice, it is possible to optimize uncertainty against the costs and usability of instrumentation and data systems.
Higher order visual areas enhance stimulus responsiveness in mouse primary visual cortex
Authors: Oude Lohuis Matthijs N , Canton Alexis Cervan , Pennartz Cyriel M A , Olcese Umberto
Published: October 2021

Over the past few years, the various areas that surround the primary visual cortex (V1) in the mouse have been associated with many functions, ranging from higher order visual processing to decision-making. Recently, some studies have shown that higher order visual areas influence the activity of the primary visual cortex, refining its processing capabilities. Here, we studied how in vivo optogenetic inactivation of two higher order visual areas with different functional properties affects responses evoked by moving bars in the primary visual cortex. In contrast with the prevailing view, our results demonstrate that distinct higher order visual areas similarly modulate early visual processing. In particular, these areas enhance stimulus responsiveness in the primary visual cortex, by more strongly amplifying weaker compared with stronger sensory-evoked responses (for instance specifically amplifying responses to stimuli not moving along the direction preferred by individual neurons) and by facilitating responses to stimuli entering the receptive field of single neurons. Such enhancement, however, comes at the expense of orientation and direction selectivity, which increased when the selected higher order visual areas were inactivated. Thus, feedback from higher order visual areas selectively amplifies weak sensory-evoked V1 responses, which may enable more robust processing of visual stimuli.
Real Effects of Financial Distress: The Role of Heterogeneity
Authors: Buera Francisco , Karmakar Sudipto
Published: October 2021

Which firms are more sensitive to an aggregate financial shock? What can be learnt from these heterogeneous responses? We evaluate and answer these questions from both empirical and theoretical perspectives. Using microdata from Portugal during the sovereign debt crisis we find that highly leveraged firms and firms with a larger share of short-term debt on their balance sheets contracted more in the aftermath of the financial shock. We analyse the conditions under which leverage and debt maturity determine the sensitivity of firms’ investment decisions to financial shocks in standard models of investment under financial frictions. In doing so, we extend these models to feature a maturity choice. We show that simple versions of these models are not consistent with the observed heterogeneous responses. The model needs the presence of frictions when issuing long-term debt to rationalise the empirical findings.
Predictive model for in-hospital mortality following cardiogenic shock
Authors: Garcia-Rodeja Arias F , Perez Dominguez M , Martinon Martinez J , Garcia Acuna J M , Abou Joch Casas C , Rigueiro Veloso P , Agra Bermejo R M , Iglesias Alvarez D , Alvarez Alvarez B , Gonzalez Ferrero T , Cacho Antonio C , Antunez Muinos P J , Gonzalez Juanatey J R
Published: October 2021

Introduction and objectives

Cardiogenic shock is a condition caused by reduced cardiac output and hypotension, resulting in end-organ damage and multiorgan failure. Although prognosis has been improved in recent years, this state is still associated with high morbidity and mortality. The aim of our study was to perform a predictive model for in-hospital mortality that allows stratifying the risk of death in patients with cardiogenic shock.

Methods

This is a retrospective analysis from a prospective registry, that included 135 patients from one Spanish Universitary Hospital between 2011 and 2020. Multivariate analysis was performed among those variables with significant association with short-term outcome of univariate analysis with a p-value <0.2. Those variables which had a p-value >0.1 in the multivariable analysis were excluded of the final model. Our method was assessed using the area under the ROC-curve (AUC). Goodness of fit was tested using Hosmer-Lemeshow statistic test. Finally, we performed a risk score using the pondered weight of the coefficients of a simplified model created after categorizing the continuous quantitative variables included in the final model, giving a maximum of 16 points and creating three categories of risk.

Results

The in-hospital mortality rate was 41.5%, the average of age was 74.2 years, 35.6% were females and acute coronary syndrome (ACS) was the main cause of shock (60.7%). Mitral regurgitation (moderate-severe), age, ACS etiology, NT-proBNP, blood hemoglobin and lactate at admission were included in the final model. Risk-adjustment model had good accuracy in predicting in-hospital mortality (AUC 0.85; 95% CI 0,78–0,90) and the goodness of fit test was p-value>0.10. According to the risk score made with the simplified model, these patients were stratified into three categories: low (scores 0–6), intermediate (scores 7–10), and high (scores 11–16) risk with observed mortality of 12.9%, 49.1% and 87.5% respectively (p<0,001).

Conclusions

Our predictive model using six variables, shows good discernment for in-hospital mortality and the risk score has identified three groups with significant differences in prognosis. This model could help in guiding treatments and clinical decision-making, so it needs external validation and to be compared with other models already published.

Funding Acknowledgement

Type of funding sources: None. ROC curveRisk Score
Atherosclerosis associated pathways are upregulated in stenotic aortic valves from patients with severe concomitant coronary artery disease
Authors: Plunde O , Sarajlic P , Franco-Cereceda A , Back M
Published: October 2021

Aortic valve stenosis (AVS) share pathobiology and risk factors with atherosclerosis. However, medical treatment effective against atherosclerosis lack ability to halt the progression of AVS. The aims of this study were to (i) determine the prevalence of coronary artery disease (CAD) in surgical AVS patients and (ii) to establish predictors of CAD in AVS patients and (iii) to identify differential aortic valve transcriptomic profiles depending on concomitant CAD.

The study cohort consisted of 256 consecutive AVS patients with surgically verified tricuspid aortic valves, of which 74 aortic valves were collected. CAD defined as coronary artery stenosis requiring concomitant bypass surgery or previous acute coronary syndrome or percutaneous coronary intervention Transcriptomic data were obtained from microarray analysis of tissues from three different stages of AVS process (healthy, intermediate, and calcified tissue). All comparisons were sex and tissue adjusted. Non-coding probes were removed and a variance filter was applied prior to analysis which yielded 5121 genes.

The prevalence of CAD in AVS was 49%. A logistic regression model revealed male sex, claudication, diabetes and current smoking as significant predictors of CAD when age, sex, peak transaortic velocity, hsCRP, eGFR and BMI were held constant.

28 genes were significantly (q<0.05) differentially expressed when aortic valves from patients with (n=43) and without (n=31) CAD were compared. A comparison of patients with concomitant multi vessel disease (2–3 affected vessel territories, n=20) and patients without CAD or single vessel disease (n=54) revealed 189 significantly expressed genes and an optimal visual separation on heatmap (Figure 2). Active-subnetwork-oriented-enrichment analysis identified upregulated aortic valve atherosclerosis associated pathways in multi vessel disease patients related to reactive oxygen species and cytokine signaling.

This study provides a novel observation of differential aortic valve gene expression profile depending on concomitant severe CAD. The results revealed that patients with concomitant severe CAD exhibited underlying atherosclerosis-related mechanisms to their aortic valve disease. Therefore, future precision medicine against AVS may be facilitated by assessing concomitant CAD.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Karolinska Institute - Clinical Science Training ProgrammeSwedish Heart Lung Foundation Predictors of concomitant CADDEGs in AVs stratified on severe CAD
Routine advanced echocardiography in the evaluation of cardiovascular sequelae of COVID19 survivors with elevated cardiovascular biomarkers
Authors: Rodenas Alesina E , Rodriguez-Palomares J , Oller-Bach M , Jordan P , Badia C , Herrador L , Garcia-De-Acilu M , Clau-Terre F , Gonzalez-Del-Hoyo M , Fernandez-Galera R , Servato L , Casas G , Baneras J , Ferreira-Gonzalez I
Published: October 2021

Background

COVID19 has been related to elevated CVB and biventricular dysfunction during hospitalization. However, it is unknown whether patients with biomarker elevation exhibit long-lasting abnormalities in cardiac function.

Purpose

To determine, using advanced echocardiography, the prevalence and type of cardiovascular sequelae after COVID19 infection with marked elevation of cardiovascular biomarkers (CVB), and their prognostic implications.

Methods

All patients admitted from March 1st to May 25th, 2020 to a tertiary referral hospital were included. Patients with cardiovascular disease antecedent, death during admission, or the first 30 days after discharge were excluded. Patients with hs-TnI >45 ng/L, NT-proBNP >300 pg/ml, and D-dimer >8000 ng/ml were separated based on each CVB elevation and matched with COVID controls (three biomarkers within the normal range) based on intensive care requirements and age.

Results

From a total of 2025 hospitalized COVID19 patients, 80 patients with significantly elevated CVB and 29 controls were finally included. No differences in baseline characteristics were observed among groups, but elevated CVB patients were sicker. Follow-up echocardiograms showed no differences among groups regarding LVEF or RV diameters, but TAPSE was lower if hs-TnI or D-dimer were elevated. Hs-TnI patients also had lower global myocardial work and global longitudinal strain. The presence of an abnormal echocardiogram was more frequent in the elevated CVB group compared to controls (23.8 vs 10.3%, P=0.123) but mainly associated with mild abnormalities in deformation parameters. Management did not change in any case and no major cardiovascular events except deep vein thrombosis occurred after a median follow-up of 7 months (Figure 1).

Conclusions

Minimal abnormalities in cardiac structure and function are observed in COVID19 survivors without previous cardiovascular diseases who presented a significant CVB rise at admission, with no impact on patient management or short-term prognosis. These results do not support a routine screening program after discharge in this population.

Funding Acknowledgement

Type of funding sources: None. Figure 1
Prognostic value of three dimensional-vena contracta area in patients with secondary mitral regurgitation
Authors: Yedidya I , Mantegazza V , Namazi F , Lustosa R , Butcher S C , Milhorini Pio S , Vo N M , Tamborini G , Garlasche A , Pepi M , Bax J J , Ajmone Marsan N , Delgado V
Published: October 2021

Background

Effective regurgitant orifice area (EROA) is an important quantitative measurement for mitral regurgitation (MR) grading. Yet, the accuracy of this method is limited in patients with secondary mitral regurgitation (SMR). Three-dimensional (3D) color Doppler echocardiography allows for the direct assessment of the vena contracta area (VCA). The prognostic value of 3D-VCA in patients with secondary MR has not been investigated.

Purpose

The aim of the present study was to assess the association between 3D-VCA and prognosis of patients with SMR.

Methods

A total of 218 patients (69% men, median age 74 years) with significant SMR were retrospectively analyzed. 3D-VCA was measured offline with dedicated software, from restored 3D color Doppler full volume datasets of the mitral valve (Figure 1). The population was divided according to the American College of Cardiology expert recommendation for the grading of severe MR (VCA ≥50 mm2 and VCA <50 mm2). Patients were followed up for the combined end point of all-cause mortality or heart failure hospitalization.

Results

Of the total population, 63% had an ischemic etiology, 60% had atrial fibrillation and 25% cardiac resynchronization therapy. Patients with 3D-VCA ≥50 mm2 needed more diuretic therapy, had a larger left ventricle and atrium, and had more post-procedural residual MR. A total of 82% of patients underwent MitraClip device implantation, 17% had mitral valve repair and 1% had mitral valve replacement. During a median follow-up of 28 months, 130 (60%) met the combined end point (101 (46%) patients died and 81 (37%) were hospitalized due to heart failure). When dividing the population according to the cut-off of 3D-VCA, patients with a 3D-VCA≥50 mm2 had a worse prognosis compared with their counterparts (Figure 2). In a multivariable Cox regression analysis, 3D-VCA≥50 mm2 remained independently associated with the composite endpoint of all-cause mortality or heart failure hospitalization (HR=1.454, 95% CI 1.020–2.072, p=0.038).

Conclusion

In patients with SMR, a 3D-VCA ≥50 mm2 was independently associated with a combined endpoint of death or heart failure hospitalization.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Method of 3D-VCA measurementFigure 2. Kaplan-Meier survival curve
Use of left ventricular support devices during transcatheter aortic valve replacement and balloon aortic valvuloplasty: a single center experience
Authors: Mahmood S , Gelovani D , Nona P , Lemor A , Basir M , Frisoli T , Lee J , Wang D , O'Neill B , Eng M , O'Neill W , Villablanca P
Published: October 2021

Background

Transcatheter aortic valve replacement (TAVR) and balloon aortic valvuloplasty (BAV) are definitive and bridging therapies in patients with aortic stenosis. Data on utilization of mechanical circulatory support (MCS) in this population is scarce. This study sought to evaluate the clinical outcomes of the use of Impella (Abiomed, Danvers, MA) in patients undergoing TAVR or BAV at a tertiary-care center.

Methods

We reviewed all TAVRs and BAVs that required Impella from 2012 and 2020. Patient demographics, procedural outcomes, complications, and 30-day mortality were analyzed.

Results

A total of 1,965 TAVR and 715 BAV cases were performed in the study period. 30 TAVR and 94 BAV cases required an Impella. 65% of these cases were due to cardiogenic shock (CS) (100% of TAVR and 55% of BAV). 31% were performed in female patients. Transfemoral access was utilized in 98% of cases. Impella CP was used in 98% of cases, other types of MCS were used in 8.7% of cases. 32.2% of cases required MCS for more than 24 hours. In the TAVR population the indication for MCS was 46.6% profound hypotension post valve deployment requiring vasopressors, 16.6% cardiac arrest, 10% sustained ventricular arrhythmia, 10% cardiac tamponade [Office1] and 10% coronary occlusion. In the BAV group the indication was 44% high-risk PCI and 56% CS. The 30-day mortality in TAVR was 40% and 28% in BAV; from the BAV group in CS the mortality was 45%. VARC-2 vascular complications and bleeding complications were observed in 4.8% and 1.5%, respectively. 0.7% of the total cohort required conversion to open-heart surgery.

Conclusions

Impella support is required in a minority of TAVR or BAV cases. In those who require MCS with Impella for either BAV or TAVR, the total mortality remains high especially in those experiencing CS.

Funding Acknowledgement

Type of funding sources: None.
Primary hemostatic disorders drive early and late major bleedings of patients with atrial fibrillation after transcatheter aortic valve replacement
Authors: Matsushita K , Marchandot B , Hess S , Kibler M , Sato C , Heger J , Truong D P , Trimaille A , Sattler L , Grunebaum L , Reydel A , Jesel L , Ohlmann P , Morel O
Published: October 2021

Introduction

Patients with atrial fibrillation (AF) are likely to have multiple co-morbidities and receive anticoagulants after TAVR, which lead to a poor prognosis including bleeding events. Closure time adenosine diphosphate (CT-ADP) is a primary hemostasis point-of-care test used as a surrogate marker of high molecular weight (HMW) multimers defect of Von Willebrand factor (VWF). Our prior studies suggest that prolongation of CT-ADP (>180 seconds) after TAVR is a major determinant of early and late major/life-threatening bleeding complications (MLBCs).

Purpose

To evaluate the impact of post-procedural CT-ADP >180sec on bleeding events in AF patients.

Methods

We included 878 patients from our prospective TAVR registry between 2010 and 2019. Bleeding complications were assessed according to the VARC-2 (Valve Academic Research Consortium-2) criteria. Major adverse cardiac and cerebrovascular events (MACCE) was defined as a composite of all-cause death, myocardial infarction, stroke, and heart failure hospitalization within 1-year after TAVR. Ongoing primary haemostasis disorder was defined by post-procedure CT-ADP >180sec. Primary endpoint was the occurrence of MLBCs during the first year and the second endpoint was 1-year MACCE.

Results

Patients with AF had a higher incidence of all-cause mortality (15% vs. 8%, p=0.002), MACCE (29% vs. 20%, p=0.002), and MLBCs (20% vs. 12%, p=0.001) within 1-year compared to non-AF patients. When the cohort was split into 4 subgroups according to AF and CT-ADP >180sec, patients with AF and CT-ADP >180sec had the highest risk of MLBCs (log-rank test; p<0.001) (Figure). Multivariate Cox regression analysis confirmed that the patients with AF and CT-ADP >180sec had 4.6-fold higher risk of MLBCs within 1 year compared to non-AF patients with CT-ADP ≤180sec (hazard ratio: 4.60; 95% confidence interval: 2.18 - 9.68; p<0.001).

Conclusion

Among TAVR patients, AF with post-procedural CT-ADP >180 sec was identified as a strong independent predictor of MLBCs at 1-year follow-up. Our study suggest that persistent primary haemostasis disorders contribute to a higher risk of bleeding events particularly in AF patients and may be considered for a tailored and risk-adjusted antithrombotic therapy after TAVR.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Matsushita received a grant from Edwards Lifesciences.
How to distinguish between hypertrophic cardiomyopathy and left ventricular hypertrophy secondary to Fabry disease?
Authors: Menezes Fernandes R , Azevedo O , Cordeiro F , Lourenco M R , Lourenco A
Published: October 2021

Introduction

Fabry disease (FD) commonly leads to left ventricular hypertrophy (LVH) that could mimic sarcomeric hypertrophic cardiomyopathy (HCM).

Purpose

To determine the differences in echocardiographic parameters between FD patients with LVH and HCM patients.

Methods

We conducted a prospective study encompassing FD patients followed in a Reference Center of Lysosomal Storage Disorders. All patients performed a complete echocardiographic evaluation, including left ventricular strain analysis by two-dimensional speckle tracking imaging. Demographic, clinical characteristics and echocardiographic parameters were analysed. FD patients with LVH were compared with HCM patients, using Chi-square test for categorical variables and Student's T-test for continuous variables. The significance level was 0,05.

Results

A total of 91 FD patients were included, with a median age of 51 years-old and 62,6% of female predominance. 16,5% of patients were under enzymatic replacement therapy with agalsidase alpha and 7,7% were treated with chaperone therapy (migalastat). 33 FD patients (36%) had LVH and were older than HCM patients (63,6 vs 59,3 years-old; p=0,106). FD patients with LVH had lower interventricular septum (IVS) thickness (16,4 vs 19,6 mm, p<0,001), IVS/posterior wall ratio (1,3 vs 1,8, p<0,001), and left atrial volume index (34,45 vs 42,2 ml/m2; p=0,014). Left ventricle mass index was similar between the two groups (157,7 vs 155,5 g/m2; p=0,819), with lower left ventricular ejection fraction in FD patients (64,5% vs 70,5%; p<0,001). There were no significant differences in global longitudinal strain (−15,6% vs 15,9%; p=0,687), global circumferential strain (−19,9% vs −21,1%; p=0,218) and global radial strain (35,3% vs 33,7%; p=0,623). Interestingly, FD patients had lower base-to-apex circumferential strain gradient (5,7% vs 9,1%; p=0,002) and lower twist (17,5° vs 26,1°; p=0,001) than HCM patients. No significant differences were reported regarding mechanical dispersion (72,4 vs 71,2 ms; p=0,841).

Conclusion

The pattern of LVH is different between FD and HCM patients. In our study, we revealed that base-to-apex circumferential strain gradient and twist are echocardiographic parameters that could help distinguish both entities.

Funding Acknowledgement

Type of funding sources: None.
Development of a risk-score for pericarditis recurrence in patients with a first episode of acute pericarditis
Authors: Lazarou E , Lazaros G , Antonopoulos A S , Imazio M , Vasileiou P , Karavidas A , Toutouzas K , Vassilopoulos D , Tsioufis C , Tousoulis D , Vlachopoulos C
Published: October 2021

Background/Introduction

Currently we remain uncertain about which patients are at increased risk for recurrent pericarditis.

Purpose

We developed a risk score for pericarditis recurrence in patients with acute pericarditis.

Methods

We prospectively recruited 262 patients with acute pericarditis. Patients' demographics, clinical, imaging and laboratory data at presentation, were collected. Patients were followed-up for a median of 51 months (interquartile range 21–71) for recurrence. Variables with <10% missingness were entered into multivariable logistic regression models with stepwise elimination to explore independent predictors of recurrence. The performance of the final model was assessed by the c-index and model's calibration and the optimism corrected c-index were evaluated after 10-fold cross-validation.

Results

We identified six independent predictors for pericarditis recurrence i.e., age, effusion size, platelet count (negative predictors) and reduced inferior vena cava collapse, in-hospital use of corticosteroids, and heart rate (positive predictors). The final model had good performance for recurrence, c-index 0.783 (95% CI 0.725–0.842), while the optimism corrected c-index after cross-validation was 0.752. Based on these variables we developed a risk score point system for recurrence (0–22 points) with equally good performance (c-index 0.740, 95% CI 0.677–0.803). Patients with a low score (0–7 points) had 21.3% risk for recurrence, while those with high score (≥12 points) had a 69.8% risk for recurrence (Figure 1). The score was predictive of recurrence among most patient subgroups.

Conclusions

A simple risk score point system based on 6 variables can be used to predict the individualized risk for pericarditis recurrence among patients with a first episode of acute pericarditis.

Funding Acknowledgement

Type of funding sources: None. Figure 1