bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the (Cu,C)Ba2Ca3Cu4O

11+δ

single crystals grown under high pressure
Authors: He Chengping , Ming Xue , Si Jin , Zhu Xiyu , Wang Jinhua , Wen Hai-Hu
Published: October 2021

By using a high pressure and high temperature (3.7 GPa, 1120 ∘C) synthesis technique, we have grown (Cu,C)Ba2Ca3Cu4O

11
+
δ

single crystals. X-ray diffraction, scanning electron microscopy, resistivity, and magnetization measurements are carried out and all show that the samples have good quality. The single crystal has onset and zero-resistance transition temperatures of about 111 and 109.6 K, indicating a very narrow transition width, which is consistent with a rather sharp magnetization transition. Magnetization hysteresis loops (MHLs) are also measured, showing a pronounced second peak effect in the intermediate temperature region. The magnetic critical current density calculated from the MHLs at 77 K and 1.5 T is about 6.4 × 104 A cm−2. By using a criterion of 1

%

normal state resistivity, we have determined the irreversibility line which exhibits an irreversibility field of about 8 T at 77 K. Compared with other layered systems, it is easy to find that the irreversibility line is rather high and could be further improved with the optimized transition temperature of about 118 K as previously discovered in polycrystalline samples.
Phase transitions in four-dimensional AdS black holes with a nonlinear electrodynamics source
Authors: Bécar Ramón , González P A , Saavedra Joel , Vásquez Yerko , Wang Bin
Published: October 2021

In this work we consider black hole solutions to Einstein’s theory coupled to a nonlinear power-law electromagnetic field with a fixed exponent value. We study the extended phase space thermodynamics in canonical and grand canonical ensembles, where the varying cosmological constant plays the role of an effective thermodynamic pressure. We examine thermodynamical phase transitions in such black holes and find that both first- and second-order phase transitions can occur in the canonical ensemble while, for the grand canonical ensemble, Hawking–Page and second-order phase transitions are allowed.
Shell evolution in neutron-rich nuclei: the single particle perspective *
Authors: Ma Wei-Qiang , Qian Yi-Bin
Published: October 2021

The isospin dependence of spin-orbit (SO) splitting becomes increasingly important as N/Z increases in neutron-rich nuclei. Following the initial independent-particle strategy toward explaining the occurrence of magic numbers, we systematically investigated the isospin effect on the shell evolution in neutron-rich nuclei within the Woods-Saxon mean-field potential and the SO term. It is found that new magic numbers N = 14 and N =16 may emerge in neutron-rich nuclei if one changes the sign of the isospin-dependent term in the SO coupling, whereas the traditional magic number, N = 20, may disappear. The magic number N = 28 is expected to be destroyed despite the sign choice of the isospin part in the SO splitting, corresponding to the strength of the SO coupling term. Meanwhile, the N = 50 and 82 shells may persist within the single particle scheme, although there is a decreasing trend of their gaps toward extreme proton-deficient nuclei. Besides, an appreciable energy gap appears at N = 32 and 34 in neutron-rich Ca isotopes. All these results are more consistent with those of the interacting shell model when enhancing the strength of the SO potential in the independent particle model. The present study may provide a more reasonable starting point than the existing one for not only the interacting shell model but also other nuclear many-body calculations toward the neutron-dripline of the Segrè chart.
Geopolymerization: a promising technique for membrane synthesis
Authors: Sadiq Muhammad , Naveed Amir , Arif Muhammad , Hassan Saima , Afridi Shaista , Asif Muhammad , Sultana Sabeeh , Amin Noor-ul , Younas Mohammad , Khan Muhammad Naeem , Jiang Heqing , Gul Saeed
Published: October 2021

Ceramic membranes are considered superior over their polymeric counterparts for applications at high temperature, pressure, and in aggressive environments with additional advantages of cleaning at high temperature. Preparation of porous ceramic membrane is expensive because the ceramic materials cannot be processed in a liquid state as polymers. Ceramic membrane synthesis involved solid powder preparation, consolidation, suspension formation, calcination, and sintering temperature which makes its synthesis very expensive. Geopolymerization is a heterogeneous reaction of aluminosilicate materials and chemical activators to form a three-dimensional structure having high mechanical strength without sintering. The overall percent energy and cost-saving of geopolymeric membranes were compared with conventional ceramic membranes. Recently, the geopolymerization technique has been used for membrane synthesis to replace conventional ceramic membrane synthesis. The objective of this review article is to discuss the potential opportunities and challenges in the synthesis and application of geopolymeric membranes.
Linking the Morphology of Sternal Glands to Rubbing Behavior byVespa soror(Hymenoptera: Vespidae) Workers During Recruitment for Group Predation
Authors: Mattila Heather R , Shimano Satoshi , Otis Gard W , Nguyen Lien T P , Maul Erica R , Billen Johan
Published: October 2021

The activities of social insect colonies are supported by exocrine glands and the tremendous functional diversity of the compounds that they secrete. Many social wasps in the subfamilies Vespinae and Polistinae have two sternal glands—the van der Vecht and Richards’ glands—that vary in their features and function across the species in which they are found. Field observations suggest that giant hornets use secretions from the van der Vecht gland to chemically mark targeted nests when workers initiate group attacks on social insect prey. However, descriptions of giant hornets’ sternal glands and details about their recruitment behavior are lacking. We describe the morphology of the sternal glands of the giant hornet Vespa soror du Buysson and consider their potential to contribute to a marking pheromone. We also assess the gastral rubbing behavior of workers as they attacked Apis cerana F. (Hymenoptera: Apidae) colonies. V. soror workers have well-developed van der Vecht and Richards’ glands on their terminal gastral sternites, with morphologies that robustly support the synthesis, storage, and dissemination of their secretory products. Observations confirm that the van der Vecht gland is exposed during gastral rubbing, but that the Richards’ gland and glands associated with the sting apparatus may also contribute to a marking pheromone. Workers briefly but repeatedly rubbed their gasters around hive entrances and on overhead vegetation. Colonies were heavily marked over consecutive attacks. Our findings provide insight into the use of exocrine secretions by giant hornets as they recruit nestmates to prey colonies for group attacks.
Rapid Review of Dermal Penetration and Absorption of Inorganic Lead Compounds for Occupational Risk Assessment
Authors: Niemeier Richard Todd , Maier Andrew , Reichard John F
Published: October 2021

Lead (Pb) exposure continues to be a significant public health issue in both occupational and non-occupational settings. The vast majority of exposure and toxicological studies have focused on effects related to inhalation and gastrointestinal exposure routes. Exposure to inorganic Pb compounds through dermal absorption has been less well studied, perhaps due to the assumption that the dermal pathway is a minor contributor to aggregate exposures to Pb compounds. The aim of this rapid review was to identify and evaluate published literature on dermal exposures to support the estimation of key percutaneous absorption parameters (Kp, flux, diffusion rate) for use in occupational risk assessment. Eleven articles were identified containing information from both in vitro and in vivo systems relevant to percutaneous absorption kinetics. These articles provided 24 individual study summaries and information for seven inorganic Pb compounds. The vast majority of study summaries evaluated (n = 22, 92%) reported detectable amounts of dermal absorption of inorganic Pb. Data were identified for four Pb compounds (Pb acetate, Pb nitrate, Pb oxide, and Pb metal) that may be sufficient to use in evaluating physiologically based pharmacokinetic models. Average calculated diffusion rates for the pool of animal and human skin data ranged from 10−7 to 10−4 mg cm−2 h−1, and Kp values ranged from 10−7 to 10−5 cm h−1. Study design and documentation were highly variable, and only one of the studies identified was conducted using standard test guideline-compliant methodologies. Two studies provided quality estimates on the impacts of dermal absorption from water-insoluble Pb compounds on blood Pb levels. These two studies reported that exposures via dermal routes could elevate blood Pb by over 6 µg dl−1. This estimation could represent over 100% of 5 µg dl−1, the blood Pb associated with adverse health effects in adults. The utility of these estimates to occupational dermal exposures is limited, because the confidence in the estimates is not high. The literature, while of limited quality, overall strongly suggests inorganic Pb has the potential for dermal uptake in meaningful amounts associated with negative health outcomes based on upper bound diffusion rate estimates. Future standard test guideline-compliant studies are needed to provide high-confidence estimates of dermal uptake. Such data are needed to allow for improved evaluation of Pb exposures in an occupational risk assessment context.
Simulated herbivory enhances leaky sex expression in the dioecious herbMercurialis annua
Authors: Villamil Nora , Li Xinji , Seddon Emily , Pannell John R
Published: October 2021

Background and Aims

Plant reproductive traits are widely understood to be responsive to the selective pressures exerted by pollinators, but there is also increasing evidence for an important role for antagonists such as herbivores in shaping these traits. Many dioecious species show leaky sex expression, with males and females occasionally producing flowers of the opposite sex. Here, we asked to what extent leakiness in sex expression in Mercurialis annua (Euphorbiaceae) might also be plastically responsive to simulated herbivory. This is important because enhanced leakiness in dioecious populations could lead to a shift in both the mating system and in the conditions for transitions between combined and separate sexes.

Methods

We examined the effect of simulated herbivory on the sexual expression of males and females of M. annua in two experiments in which different levels of simulated herbivory led to enhanced leakiness in both sexes.

Key Results

We showed that leaky sex expression in both males and females of the wind-pollinated dioecious herb M. annua is enhanced in response to simulated herbivory, increasing the probability for and the degree of leakiness in both sexes. We also found that leakiness was greater in larger females but not in larger males.

Conclusions

We discuss hypotheses for a possible functional link between herbivory and leaky sex expression, and consider what simulated herbivory-induced leakiness might imply for the evolutionary ecology of plant reproductive systems, especially the breakdown of dioecy and the evolution of hermaphroditism.
Artificial intelligence in the prediction of protein–ligand interactions: recent advances and future directions
Authors: Dhakal Ashwin , McKay Cole , Tanner John J , Cheng Jianlin
Published: October 2021

New drug production, from target identification to marketing approval, takes over 12 years and can cost around $2.6 billion. Furthermore, the COVID-19 pandemic has unveiled the urgent need for more powerful computational methods for drug discovery. Here, we review the computational approaches to predicting protein–ligand interactions in the context of drug discovery, focusing on methods using artificial intelligence (AI). We begin with a brief introduction to proteins (targets), ligands (e.g. drugs) and their interactions for nonexperts. Next, we review databases that are commonly used in the domain of protein–ligand interactions. Finally, we survey and analyze the machine learning (ML) approaches implemented to predict protein–ligand binding sites, ligand-binding affinity and binding pose (conformation) including both classical ML algorithms and recent deep learning methods. After exploring the correlation between these three aspects of protein–ligand interaction, it has been proposed that they should be studied in unison. We anticipate that our review will aid exploration and development of more accurate ML-based prediction strategies for studying protein–ligand interactions.
Adding Tree Rings to North America's National Forest Inventories: An Essential Tool to Guide Drawdown of Atmospheric CO2
Authors: Evans Margaret E K , DeRose R Justin , Klesse Stefan , Girardin Martin P , Heilman Kelly A , Alexander M Ross , Arsenault André , Babst Flurin , Bouchard Mathieu , Cahoon Sean M P , Campbell Elizabeth M , Dietze Michael , Duchesne Louis , Frank David C , Giebink Courtney L , Gómez-Guerrero Armando , García Genaro Gutiérrez , Hogg Edward H , Metsaranta Juha , Ols Clémentine , Rayback Shelly A , Reid Anya , Ricker Martin , Schaberg Paul G , Shaw John D , Sullivan Patrick F , GaytÁn Sergio Armando Villela
Published: October 2021

Tree-ring time series provide long-term, annually resolved information on the growth of trees. When sampled in a systematic context, tree-ring data can be scaled to estimate the forest carbon capture and storage of landscapes, biomes, and—ultimately—the globe. A systematic effort to sample tree rings in national forest inventories would yield unprecedented temporal and spatial resolution of forest carbon dynamics and help resolve key scientific uncertainties, which we highlight in terms of evidence for forest greening (enhanced growth) versus browning (reduced growth, increased mortality). We describe jump-starting a tree-ring collection across the continent of North America, given the commitments of Canada, the United States, and Mexico to visit forest inventory plots, along with existing legacy collections. Failing to do so would be a missed opportunity to help chart an evidence-based path toward meeting national commitments to reduce net greenhouse gas emissions, urgently needed for climate stabilization and repair.
Machine learning for the life-time risk prediction of Alzheimer’s disease: a systematic review
Authors: Rowe Thomas W , Katzourou Ioanna K , Stevenson-Hoare Joshua O , Bracher-Smith Matthew R , Ivanov Dobril K , Escott-Price Valentina
Published: October 2021

Alzheimer’s disease is a neurodegenerative disorder and the most common form of dementia. Early diagnosis may assist interventions to delay onset and reduce the progression rate of the disease. We systematically reviewed the use of machine learning algorithms for predicting Alzheimer’s disease using single nucleotide polymorphisms and instances where these were combined with other types of data. We evaluated the ability of machine learning models to distinguish between controls and cases, while also assessing their implementation and potential biases. Articles published between December 2009 and June 2020 were collected using Scopus, PubMed and Google Scholar. These were systematically screened for inclusion leading to a final set of 12 publications. Eighty-five per cent of the included studies used the Alzheimer's Disease Neuroimaging Initiative dataset. In studies which reported area under the curve, discrimination varied (0.49–0.97). However, more than half of the included manuscripts used other forms of measurement, such as accuracy, sensitivity and specificity. Model calibration statistics were also found to be reported inconsistently across all studies. The most frequent limitation in the assessed studies was sample size, with the total number of participants often numbering less than a thousand, whilst the number of predictors usually ran into the many thousands. In addition, key steps in model implementation and validation were often not performed or unreported, making it difficult to assess the capability of machine learning models.
Cross-task adaptation effects of bilingual language control on cognitive control: a dual-brain eeg examination of simultaneous production and comprehension
Authors: Liu Huanhuan , Li Wanqing , Zuo Mingyue , Wang Fenqi , Guo Zibin , Schwieter John W
Published: October 2021

For bilinguals, speaking and listening are assisted by complex control processes including conflict monitoring and inhibition. However, the extent to which these processes adapt to linguistic and situational needs has been examined separately for language production and comprehension. In the present study, we use a dual-EEG to record the carry-over effects of language control on general cognitive control in three language contexts (single-first language [L1], single-second language [L2], and mixed). Chinese learners of English were placed in dyads in which one participant was asked to name pictures while the other listened. Interleaved after each naming/listening trial were flanker trials. The results from picture naming and listening revealed higher delta and theta synchronization in the single-L2 and mixed contexts compared with the single-L1 context and higher theta synchronization in the mixed context compared with the single-L2 and single-L1 contexts. The results from the interleaved flanker trials demonstrated that inhibition was adaptively generalized in the single-L2 and mixed contexts. Altogether, the findings support the natural adaptation of language control to cognitive control and underscore the importance of linguistic context. We argue that these adaptive patterns have the potential to affect corresponding control processes across language and cognitive control tasks.
Evidence of Brain Alterations in Noncerebral Falciparum Malaria
Authors: Mohanty Sanjib , Sahu Praveen K , Pattnaik Rajyabardhan , Majhi Megharay , Maharana Sameer , Bage Jabamani , Mohanty Akshaya , Mohanty Anita , Bendszus Martin , Patterson Catriona , Gupta Himanshu , Dondorp Arjen M , Pirpamer Lukas , Hoffmann Angelika , Wassmer Samuel C
Published: October 2021

Background

Cerebral malaria in adults is associated with brain hypoxic changes on magnetic resonance (MR) images and has a high fatality rate. Findings of neuroimaging studies suggest that brain involvement also occurs in patients with uncomplicated malaria (UM) or severe noncerebral malaria (SNCM) without coma, but such features were never rigorously characterized.

Methods

Twenty patients with UM and 21 with SNCM underwent MR imaging on admission and 44–72 hours later, as well as plasma analysis. Apparent diffusion coefficient (ADC) maps were generated, with values from 5 healthy individuals serving as controls.

Results

Patients with SNCM had a wide spectrum of cerebral ADC values, including both decreased and increased values compared with controls. Patients with low ADC values, indicating cytotoxic edema, showed hypoxic patterns similar to cerebral malaria despite the absence of deep coma. Conversely, high ADC values, indicative of mild vasogenic edema, were observed in both patients with SNCM and patients with UM. Brain involvement was confirmed by elevated circulating levels of S100B. Creatinine was negatively correlated with ADC in SNCM, suggesting an association between acute kidney injury and cytotoxic brain changes.

Conclusions

Brain involvement is common in adults with SNCM and a subgroup of hospitalized patients with UM, which warrants closer neurological follow-up. Increased creatinine in SNCM may render the brain more susceptible to cytotoxic edema.
Successful treatment of calciphylaxis with vitamin K in a patient on haemodialysis
Authors: Wajih Zainab , Singer Richard
Published: October 2021

Calciphylaxis has high mortality. Vitamin K deficiency is common in haemodialysis patients and may be a trigger for calciphylaxis due to its role in activating a tissue inhibitor of calcification, matrix Gla protein. We report a second case of a female haemodialysis patient who developed calciphylaxis twice and was successfully treated with vitamin K supplementation on both occasions. She did not receive sodium thiosulphate or bisphosphonates nor was there a change made to her dialysis time or prescription. This case highlights how supplementation with vitamin K may improve the outcome of this condition.
Sharing roosts but not ectoparasites: high host-specificity in bat flies and wing mites of Miniopterus schreibersii and Rhinolophus ferrumequinum (Mammalia: Chiroptera)
Authors: Pejić Branka , Budinski Ivana , van Schaik Jaap , Blagojević Jelena
Published: October 2021

Schreiber’s bent-winged bat Miniopterus schreibersii and the greater horseshoe bat Rhinolophus ferrumequinum are widespread and common cavernicolous species across southern Europe that host numerous specialized ectoparasite species. The objective of this study was to characterize the species assemblage, genetic diversity, and host specificity of bat flies (Nycteribiidae, Diptera) and wing mites (Spinturnicidae, Acari) found on these bat hosts in Serbia and Bosnia and Herzegovina. Notably, while bat flies lay puparia on the cave walls and can thus be transmitted indirectly, wing mites require direct body contact for transmission. Morphological identification and sequencing of a 710-bp fragment of cytochrome oxidase I gene of 207 bat flies yielded 4 species, 3 on M. schreibersii and 1 on R. ferrumequinum. Sequencing of a 460-bp small subunit ribosomal RNA fragment, in all 190 collected wing mites revealed 2 species, 1 per host. In no case was a parasite associated with 1 host found on the other host. Species and genetic diversity of flies were higher in M. schreibersii, likely reflecting their host’s larger colony sizes and migratory potential. Mite species of both hosts showed similarly low diversity, likely due to their faster life history and lower winter survival. Our findings highlight a remarkably high host-specificity and segregation of ectoparasite species despite direct contact among their hosts in the roost, suggesting a defined host preference in the investigated ectoparasite species. Furthermore, the differences in ectoparasite genetic diversity exemplify the interplay between host and parasite life histories in shaping parasite population genetic structure.
Leveraging the potential of machine learning for assessing vascular ageing: state-of-the-art and future research
Authors: Bikia Vasiliki , Fong Terence , Climie Rachel E , Bruno Rosa-Maria , Hametner Bernhard , Mayer Christopher , Terentes-Printzios Dimitrios , Charlton Peter H
Published: October 2021

Vascular ageing biomarkers have been found to be predictive of cardiovascular risk independently of classical risk factors, yet are not widely used in clinical practice. In this review, we present two basic approaches for using machine learning (ML) to assess vascular age: parameter estimation and risk classification. We then summarize their role in developing new techniques to assess vascular ageing quickly and accurately. We discuss the methods used to validate ML-based markers, the evidence for their clinical utility, and key directions for future research. The review is complemented by case studies of the use of ML in vascular age assessment which can be replicated using freely available data and code.
Stroke prevention with direct oral anticoagulants in high-risk elderly atrial fibrillation patients at increased bleeding risk
Authors: Chao Tze-Fan , Chan Yi-Hsin , Chiang Chern-En , Tuan Ta-Chuan , Liao Jo-Nan , Chen Tzeng-Ji , Lip Gregory Y H , Chen Shih-Ann
Published: October 2021

Aims

Elderly atrial fibrillation (AF) patients with risk factors of bleeding are often considered ineligible for standard oral anticoagulants (OACs). The Edoxaban Low-Dose for EldeR CARE AF patients (ELDERCARE-AF) trial recently showed that edoxaban 15 mg/day was superior to placebo for preventing stroke or systemic embolism and did not result in a significantly higher incidence of major bleeding. Our aim was to investigate a real-world cohort of AF patients similar to the ELDERCARE-AF cohort, with regard to the impact of direct oral anticoagulant (DOAC) use compared to non-OAC use, in relation to clinical outcomes.

Methods and results

From 1 January 2012 to 31 December 2016, 15 183 AF patients aged ≥80 years (mean age 86.63 years [SD 4.79]; 48.7% male) with a congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and prior stroke or transient ischemic attack (CHADS2) score ≥2 who met the enrolment criteria (generally similar to ELDERCARE-AF) were identified from the Taiwan National Health Insurance Research Database. Patients were categorized into two groups according to their stroke prevention strategies, i.e. without OACs (n = 9084) and DOACs (n = 6099). Patients receiving DOACs were further stratified into reduced-dose- or full-dose-regimen groups. Compared with the non-OAC group as a reference, DOAC use (whether at reduced dose or full dose) was associated with a lower risk of ischaemic stroke (adjusted hazard ratio [aHR] 0.77, 95% confidence interval [CI] 0.67–0.88) and all-cause mortality (aHR 0.39, 95% CI 0.37–0.42), while the risks of intracranial haemorrhage and major bleeding were similar. The risks of composite outcomes of ‘ischaemic stroke or mortality’ (aHR 0.42, 95% CI 0.40–0.45) and ‘ischaemic stroke or major bleeding or mortality’ (aHR 0.49, 95% CI 0.46–0.52) were significantly lower with DOAC use. When compared with the non-OAC group as the reference group, DOACs (whether reduced dose or full dose) showed a positive net clinical benefit. The results were generally consistent even after propensity matching.

Conclusion

In routine clinical care, DOACs (whether reduced or full dose) were associated with a lower risk of ischaemic stroke, mortality, and the composite endpoint, when compared with non-OAC use in high-risk elderly AF patients at increased bleeding risk. Our findings provide complementary ‘real-world’ data to support the generalizability of the results of the ELDERCARE-AF trial to other DOACs in daily clinical practice.
Commemorating the Crusading Past in Late Medieval England: The Worksop Priory Tabula
Authors: Doherty James
Published: October 2021

Memory has featured prominently in recent scholarship on the crusades. In particular, the remembrance of crusaders by their descendants and associated ecclesiastical institutions in the high Middle Ages has attracted considerable attention; however, few studies have concentrated on the commemoration of crusaders in the later Middle Ages. This article examines a late fifteenth-century genealogical poem, which was produced for public display on a tablet at Worksop Priory (Nottinghamshire) and contains unique information about members of the Furnival family on the Barons’ Crusade (1239–41), in order to explore how and why medieval institutions preserved memories of crusaders into the late Middle Ages. It argues that, although inaccurate in its crusade narrative, the poem provides invaluable insights into the mechanisms of aristocratic family memory in medieval England; and it focuses on the important role of material prompts in the process of commemoration. Specifically, it suggests that an effigy of Sir Thomas de Furnival was erected at Worksop soon after his death away from home in 1241. In the absence of a written record, this cenotaph acted as a prompt to an oral narrative tradition which informed the Worksop poet when he came to compose his genealogical work. This study is, therefore, an analysis of crusade memory, but it is also an examination of the presentation of a crusade narrative to a public audience, an opportunity to unravel the confused history of three crusading brothers, and an attempt to understand the response of a medieval community that had suffered losses in overseas ventures.
Prognostic value of atrial fibrillation in COVID-19 admitted patients
Authors: Santos Sanchez A , Gonzalez-Recio P E , Sanchez-Corral E , Jimenez-Nacher J J
Published: October 2021

Introduction/Background

COVID-19 is the disease caused by SARS-Cov2. Various prognostic factors have been studied and described. Atrial fibrillation (AF) is an arrhythmia associated with increased complications and mortality in acute situations. The onset of AF in patients hospitalized for COVID-19 could associate a worse prognosis during admission and in the short term.

Purpose

The objective of this study is to evaluate the adverse events in the population admitted for COVID-19 that develops AF as well as its possible prognostic value.

Methods

Retrospective, cohort study on 391 patients admitted for COVID-19 in a tertiary hospital. Descriptive and comparative analysis between those with new onset AF versus those who had AF previously in terms of: baseline characteristics, In hospital mortality, bleeding and thrombotic phenomena. Follow-up during three months after discharge. Univariate and multivariate analysis of in-hospital and three-months mortality is also performed.

Results

391 patients were included. 21 of them developed AF. These patients are older, more hypertensive and with more history of cardiopathy. At admission, they presented higher mortality (52.4% vs 19.7%; p<0.001) and bleeding (19% vs 8.4%; p<0.001), also compared to those with previous AF (not significant). New onset AF is not an independent predictor of in-hospital mortality, but rather an independent predictor of three-month mortality. In-hospital mortality predictors are: age >70 years, BCRSS scale >2 points, and severe hypotension. Three-month mortality predictors are: high-sensitive T-troponin <50ng/dl, age >70 years, BCRSS scale >2, creatinine >1.5 mg/dl and new-onset AF.

Conclusions

New onset AF appears in 5,3% of these hospitalized patients, who have greater comorbidity, bleeding and in-hospital mortality as well as three-months mortality. New onset AF is not an independent predictor of in-hospital mortality but rather an independent predictor of mortality during the first three months after discharge

Funding Acknowledgement

Type of funding sources: None. Table 1Figure 1. ROC curves
Risk of atrial fibrillation in young adults aged 20 to 39 years with isolated diastolic, isolated systolic, and systolic-diastolic hypertension: a nationwide population-based study
Authors: Lee S R , Han K D , Choi E K , Ahn H J , Oh S , Lip G Y H
Published: October 2021

Background

There is limited evidence regarding the comparative risks of incident atrial fibrillation (AF) associated with stage 1 isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH), especially amongst young adults aged 20–39 years.

Purpose

To evaluate the association between early-stage of hypertension and AF in young adults aged 20–39 years.

Methods

From the Korean nationwide health screening database, 2,958,544 subjects aged 20–39 years who were not prescribed antihypertensive medication at the index examination in 2009 were included. Subjects were categorized into eight groups according to the 2017 American College of Cardiology/American Heart Association blood pressure (BP) guidelines: normal BP, elevated BP, stage 1 IDH, stage 1 ISH, stage 1 SDH, stage 2 IDH, stage 2 ISH, and stage 2 SDH. The primary outcome was new-onset AF during follow-up.

Results

During a median follow-up of 8.3 years, 7,347 subjects had incident AF (incidence rate, 0.3 per 1,000 person-years). Compared to the normal BP group, stage 1 IDH (adjusted hazard ratio [aHR], 1.160; 95% confidence interval [CI], 1.086–1.240) and stage 1 SDH (1.250; 1.165–1.341) were associated with higher risks of incident AF, but not stage 1 ISH. Stage 2 IDH, ISH, and SDH were associated with higher risks of incident AF by 24%, 37%, and 61%, respectively (Figure).

Conclusion

Among young adults, stage 1 IDH and SDH were associated with higher risks of incident AF compared to normal BP. The risk of incident AF with stage 2 IDH was similar to that of stage 1 SDH. Optimal BP control including diastolic BP is crucial for preventing new-onset AF, even amongst young adults.

Funding Acknowledgement

Type of funding sources: None.
Device for modeling of intra-arterial circulation: application in experimental cardiology
Authors: Germanova O , Germanov V A , Shchukin Y V , Germanov A V , Galati G
Published: October 2021

Purpose of study

Using an original device for modeling of intra-arterial blood circulation, to study the features of intravascular hemodynamics with a regular heart rhythm and with various rhythm disturbances.

Material and methods

We used an original device developed by us to simulate intra-arterial circulation (Document of invention No. RU 202780 U1). The main part of the device is a glass tube of a rotameter with a length of 365 mm, an inlet end with a diameter of 20 mm, an outlet end of 16.5 mm, which is a model of an arterial vessel. Flexible silicone tubes are attached to the rotameter on both sides, with free ends connected to an electric pump, with various modes of operation (imitation of pulse waves with regular rhythm, premature ventricular contractions (PVCs), atrial fibrillation (AF). An aqueous solution of glycerin was introduced into a closed system diluted with water corresponding to the viscosity of the blood. A 5 mm long silk thread was alternately installed inside the tube, an intravascular piezoelectric crystal pressure probe connected to an oscilloscope. Also it was injected inside the tube a dye - clerical ink.

Results

With electric pump, we simulated the spreading of the pulse wave in regular heart rate, PVCs and AF. We observed the effect of a pressure wave (deflection of a silk thread, the appearance of a turbulent flow when using a dye) on the walls of the rotameter, with the formation of standing, reflected waves during the PVCs and AF. The pressure probe registered an increase in pressure inside the tube during the spread of the 1st post-extrasystolic contraction wave up to 58%, the wave after a long pause of more than 2 seconds with AF by 44% compared to the regular rhythm.

Conclusion

A device for modeling of intra-arterial circulation allows a wide range of experimental work in cardiology, normal and pathological physiology, and biophysics.

Funding Acknowledgement

Type of funding sources: None.
Resting ECG measurements can identify abnormalities in children with catecholaminergic polymorphic ventricular tachycardia
Authors: Fridman M D , Tofighi T , Fan C P S , Hamilton R M
Published: October 2021

Background

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a rare inherited disease characterized by exercise- or emotionally-triggered life-threatening ventricular arrhythmias. The resting ECG is considered to be normal and diagnosis has depended on exercise testing that is difficult acutely post-arrest or in young children.

Purpose

To identify resting ECG abnormalities in children with CPVT through assessment of measurement matrix parameters compared to a cohort of normal children.

Methods

A discovery cohort of 65 CPVT patients from the Electrophysiology program were identified. After excluding those on antiarrhythmics or in an arrhythmia at the time of their baseline ECG, 31 cases were matched 3:1 by age and sex with 93 healthy controls. Each individual had baseline ECG parameters and 180 machine-derived ECG amplitudes and durations (measurement matrix) measured. Statistical differences between ECG measures were assessed using Student's T-Test adjusted with a False Detection Rate of 1%. Significant measures were processed in a machine-learning algorithm to derive a Tree Model to differentiate individuals with and without CPVT.

Results

No significant differences were detected between CPVT patients who had and did not have a cardiac arrest. Comparing the CPVT and control cohorts, significant repolarization differences were seen in the amplitudes of lateral (I, negative aVR, V5, V6) and anterior leads (V2, V3, V4) at the J-point, ST midpoint, ST endpoint, and T-wave. Specifically, individuals with CPVT had significantly lower mean amplitudes in all aforementioned leads except aVR where the mean amplitudes were higher. These data were then used to create a Tree Model of the discovery cohort displayed in Figure 1 with a resulting R2 of 0.74, sensitivity of 0.81, and specificity of 0.98.

Conclusions

Baseline differences in repolarization are detectable in the left and anterior chest leads using machine-derived measurements of baseline ECGs in patients with CPVT, which may guide clinical suspicion when evaluating the resting ECG. These results warrant further analysis including testing of the Tree Model with a validation cohort.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Scholar Award from the Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada to Trainee Dr. Taraneh TofighiCanadian Institute for Health Research Figure 1. CPVT Tree Model
Beat-to-beat P-wave analysis outperforms conventional P-wave indices in identifying patients with a history of paroxysmal atrial fibrillation, during sinus rhythm
Authors: Tachmatzidis D , Filos D , Tsarouchas A , Mouselimis D , Bakogiannis C , Antoniadis A , Chouvarda I , Lazaridis C , Triantafyllou C , Fragkakis N , Maglaveras N , Vassilikos V
Published: October 2021

Introduction

Atrial fibrillation (AF) is the most common arrhythmia and is associated with high risk of morbidity and mortality. In many patients, AF is of episodic character (paroxysmal AF – PAF), which makes the identification of these patients during sinus rhythm (SR) challenging.

Purpose

The aim of the present study is to compare the performance of beat-to-beat P-wave analysis with P-wave indices used as predictors of PAF, such as P-wave duration, area, voltage, axis, terminal force in V1, inter-atrial block or orthogonal type, in identifying patients with history of PAF during sinus rhythm.

Methods

Standard 12-lead ECG and 10-minute orthogonal ECG recordings were obtained from 40 consecutive patients with short history of PAF under no antiarrhythmic medication and 60 age- and sex- matched healthy controls. The P-waves on the 10-minute recordings were analyzed on a beat-to-beat basis and classified as belonging to a primary or secondary morphology according to previous study. Wavelet transform used to further analyze P-wave orthogonal signals of main morphology on a beat-to-beat basis.

Results

38 out of 327 studied features were found to differ significantly among the two groups. These features were tested for their diagnostic ability and receiver operating characteristic curves were ploted. Only 3 of them performed adequetly, with an area under curve (AUC) above 0.65; Two of them came from morphology analysis (percentage of beats following main morphology in axis X and Y) and one from wavelet analysis (max energy in high frequency zone -Y axis). Among standard P-wave indices, P-wave area in lead II was the one with the highest AUC (0.64).

Conclusion

Novel indices derived from beat-to-beat analysis outperform stadard P-wave markers in identifying patients with PAF history during sinus rhythm.

Funding Acknowledgement

Type of funding sources: None. ROC curves of most significant featuresAUC characteristics of P-wave indices
A new method for ECG recording in the prone position
Authors: Cobos Gil M A , Diz J , Islas F
Published: October 2021

Introduction

Prone ventilation is frequently used in critical patients. ECG is usually recorded transposing the precordial positions to the back (Fig. 1A). The resultant precordial leads are unpredictably different from the supine ECG and difficult to interpret.

According to the dipole theory and the concept of mirror image electrocardiogram, each precordial point has an antipodal area where a mirror precordial lead can be recorded. Fig. 1B shows the location of the antipodal areas for the precordial points

Purpose

Based on this theoretical background we propose to use these antipodal areas to record inverted precordial leads (mirror leads M1 – M6) with diagnostic and monitoring potential.

Patients and methods

We have placed the precordial electrodes in the corresponding antipodal area for each precordial point (Fig. 1B) and we have recorded prone ECG in 20 subjects (10 healthy volunteers, 10 cardiac patients) The resultant ECGs (leads M1-M6) were compared with the standard supine ECGs (v1-V6).

Results

Mirror leads show low amplitude (especially V2-V4) compared to standard precordials, but are qualitatively quite similar (but inverted) to the supine precordial leads (Fig. 2).

Conclusion

We proposed a new method to obtain ECGs in prone patients. The resultant precordial leads are comparable to the standard precordial leads.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2
High frame rate speckle tracking echocardiography to assess diastolic function
Authors: Papangelopoulou K , Orlowska M , Bezy S , Petrescu A , Werner A , Ramalli A , Voigt J U , D'hooge J
Published: October 2021

Background

Left ventricular (LV) strain rate (SR) during isovolumic relaxation (SRIVR) and early diastolic filling (SRe) has previously been shown to correlate with the invasive gold standard for LV diastolic function (i.e. the time constant of LV pressure decay tau). However, the translation of these biomarkers to the clinic has been hampered by technical limitations. Indeed, conventional speckle tracking (STE) is limited by its temporal resolution, whereas tissue Doppler imaging (TDI) is angle-dependent, labor-intensive and thus rarely used clinically nowadays.

Purpose

The aim of this study was to show that these limitations could be overcome by using a recently proposed STE algorithm operating on high frame rate (HFR) imaging data.

Methods

37 subjects (age: 64±12, 81% male) were included in the study; 16 had cardiac amyloidosis, 12 were undergoing clinically indicated left and/or right heart cardiac catheterization and 9 were healthy volunteers. Since the sequence of left ventricular activation and thus the repolarization process (i.e. relaxation) starts at mid septum, we measured SRIVR and SRe in the mid septal segment in an apical 4 chamber view using a commercially available clinical system with: (1) TDI (frame rate (FR) ∼142 Hz); (2) STE (FR ∼65 Hz). Moreover, subjects were scanned with HD-PULSE, an experimental high frame ultrasound scanner (FR ∼915 Hz) and then a manually placed contour was tracked during the cardiac cycle by a custom-made 2D HFR STE algorithm, to compute and extract SRIVR and SRe from the mid septum. Since TDI is considered the reference method to assess SR, conventional as well as HFR STE values were correlated against the TDI SR values.

Results

In 3 subjects, SRIVR could not be reliably assessed with the clinical STE approach, which we attributed to the relatively low temporal resolution of the images; all other measurements could be made in all subjects. For both biomarkers, HFR STE values correlated better with the TDI reference measurements than the clinical STE estimates (Fig.1). The latter estimates showed a systematic underestimation (bias −0.19 1/s (p<0.01) and −0.46 1/s (p<0.01) for SRIVR and SRe respectively) while no significant bias was observed for the HFR STE values. Similarly, the limits of agreement of the HFR STE values were narrower (−0.45 to +0.54 1/s and −0.94 to +0.86 1/s) than those of the clinical STE measurements (−0.85 to +0.48 1/s and −1.32 to +0.41 1/s).

Conclusions

These results show that HFR STE offers a reliable way to assess novel biomarkers of diastolic function in a user-friendly manner and can therefore facilitate their incorporation to the clinical practice.

Funding Acknowledgement

Type of funding sources: None.
Heart rate turbulence as potential adjuvant index for optimal treatment guidance in severe pulmonary artery hypertension
Authors: Simeonidou E , Triantafyllidi H , Varounis C , Ntai K , Katogiannis K , Apostolopoulou O , Orphanos S , Armaganidis A , Lekakis J
Published: October 2021

Purpose

Despite significant progress achieved in the management of pulmonary arterial hypertension (PAH), the prognosis remains poor. Sudden cardiac death is one main cause of death in advanced disease. It is already known that in pts with PAH there is an alteration in cardiac autonomic nervous activity. Heart rate turbulence (HRT) is an ECG–related autonomic marker, helpful in risk stratification of proarrhythmia and sudden cardiac death. Aim of the study was to examine HRT in patients with severe idiopathic PAH (IPAH) and its relation to disease's progress.

Methods

The study population consisted of 46 pts, (32 men and 14 women), mean age 50±9 years, Group A 20 pts: NYHA III, III–IV diagnosed as severe IPAH and Group B 26 pts: NYHA II, II–III diagnosed as moderately severe IPAH. They underwent 24h Holter monitoring-HRT analysis with calculation of 2 parameters, turbulence onset (TO) and turbulence slope (TS) (Abnormal values: TO>0, TS<2.5msec/RR). Pts were defined as HRT(+) when TO and/or TS were abnormal and as HRT(−) when both TO and TS were normal or when HRT could not be calculated because of none or too few suitable PVCs. Reassessment of HRT was undertaken in 6 mo and 1 year in case of change in clinical status. Six pts from group A and 7 pts from group B underwent HRT reassessment because of change in clinical status.

Results

Initially abnormal HRT was found in 12 out of 20 pts (n=12, 60%) in group A and in none out of 26 (n=0, 0%) in group B (p=0,001). In 5 pts out of 8 with clinical improvement and 4 pts with clinical deterioration who had HRT reassessed, significant positive correlation was found between TS and change of clinical status (r=0,64, p=0,04). There was a tendency to greater normal TS mean values with clinical improvement even in group where TS was already normal (6,95±4,5 vs 3±0,3 p=0.077).

Conclusion

In severe IPAH cardiac autonomic system impairment was demonstrated mainly as abnormal TS in HRT. Significant positive correlation between normalization of TS and clinical improvement was revealed and that raises promises for use of HRT optimization as adjuvant index to guide optimal IPAH therapy and efficacy.

Funding Acknowledgement

Type of funding sources: None.